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Sample records for fluid temperature transient

  1. Determination of transient fluid temperature using the inverse method

    NASA Astrophysics Data System (ADS)

    Jaremkiewicz, Magdalena

    2014-03-01

    This paper proposes an inverse method to obtain accurate measurements of the transient temperature of fluid. A method for unit step and linear rise of temperature is presented. For this purpose, the thermometer housing is modelled as a full cylindrical element (with no inner hole), divided into four control volumes. Using the control volume method, the heat balance equations can be written for each of the nodes for each of the control volumes. Thus, for a known temperature in the middle of the cylindrical element, the distribution of temperature in three nodes and heat flux at the outer surface were obtained. For a known value of the heat transfer coefficient the temperature of the fluid can be calculated using the boundary condition. Additionally, results of experimental research are presented. The research was carried out during the start-up of an experimental installation, which comprises: a steam generator unit, an installation for boiler feed water treatment, a tray-type deaerator, a blow down flashvessel for heat recovery, a steam pressure reduction station, a boiler control system and a steam header made of martensitic high alloy P91 steel. Based on temperature measurements made in the steam header using the inverse method, accurate measurements of the transient temperature of the steam were obtained. The results of the calculations are compared with the real temperature of the steam, which can be determined for a known pressure and enthalpy.

  2. Transient Wellbore Fluid Flow Model

    Energy Science and Technology Software Center (ESTSC)

    1982-04-06

    WELBORE is a code to solve transient, one-dimensional two-phase or single-phase non-isothermal fluid flow in a wellbore. The primary thermodynamic variables used in solving the equations are the pressure and specific energy. An equation of state subroutine provides the density, quality, and temperature. The heat loss out of the wellbore is calculated by solving a radial diffusion equation for the temperature changes outside the bore. The calculation is done at each node point in themore » wellbore.« less

  3. General Transient Fluid Flow Algorithm

    Energy Science and Technology Software Center (ESTSC)

    1992-03-12

    SALE2D calculates two-dimensional fluid flows at all speeds, from the incompressible limit to highly supersonic. An implicit treatment of the pressure calculation similar to that in the Implicit Continuous-fluid Eulerian (ICE) technique provides this flow speed flexibility. In addition, the computing mesh may move with the fluid in a typical Lagrangian fashion, be held fixed in an Eulerian manner, or move in some arbitrarily specified way to provide a continuous rezoning capability. This latitude resultsmore » from use of an Arbitrary Lagrangian-Eulerian (ALE) treatment of the mesh. The partial differential equations solved are the Navier-Stokes equations and the mass and internal energy equations. The fluid pressure is determined from an equation of state and supplemented with an artificial viscous pressure for the computation of shock waves. The computing mesh consists of a two-dimensional network of quadrilateral cells for either cylindrical or Cartesian coordinates, and a variety of user-selectable boundary conditions are provided in the program.« less

  4. Low temperature fluid blender

    NASA Technical Reports Server (NTRS)

    Repas, G. A.

    1971-01-01

    Blender supplies hydrogen at temperatures from 289 deg K to 367 deg K. Hydrogen temperature is controlled by using blender to combine flow from liquid hydrogen tank /276 deg K/ and gaseous hydrogen cylinder /550 deg K/. Blenders are applicable where flow of controlled low-temperature fluid is desired.

  5. Automated Fluid Feature Extraction from Transient Simulations

    NASA Technical Reports Server (NTRS)

    Haimes, Robert; Lovely, David

    1999-01-01

    In the past, feature extraction and identification were interesting concepts, but not required to understand the underlying physics of a steady flow field. This is because the results of the more traditional tools like iso-surfaces, cuts and streamlines were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of much interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one "snap-shot" of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments like pV3). And methods must be developed to abstract the feature and display it in a manner that physically makes sense. The following is a list of the important physical phenomena found in transient (and steady-state) fluid flow: (1) Shocks, (2) Vortex cores, (3) Regions of recirculation, (4) Boundary layers, (5) Wakes. Three papers and an initial specification for the (The Fluid eXtraction tool kit) FX Programmer's guide were included. The papers, submitted to the AIAA Computational Fluid Dynamics Conference, are entitled : (1) Using Residence Time for the Extraction of Recirculation Regions, (2) Shock Detection from Computational Fluid Dynamics results and (3) On the Velocity Gradient Tensor and Fluid Feature Extraction.

  6. High temperature drilling fluids

    SciTech Connect

    Stong, R.E.; Walinsky, S.W.

    1986-01-28

    This patent describes an aqueous drilling fluid suitable for high-temperature use. This fluid is composed of a water base. Clay is suspended in the base and from about 0.01-25 pounds per barrel total composition of a hydrolyzed terpolymer of maleic anhydride, styrene and a third monomer selected from acrylamide, methacrylamide, acrylic acid and metacrylic acid. The molar ratio of maleic anhydride to styrene to the third monomer is from about 30:10:60 to 50:40:10, and the alkali metal, ammonium and lower aliphatic amine salts thereof, the weight-average molecular weight of the hydrolyzed terpolymer is from about 500-10,000.

  7. Automated Fluid Feature Extraction from Transient Simulations

    NASA Technical Reports Server (NTRS)

    Haimes, Robert

    1998-01-01

    In the past, feature extraction and identification were interesting concepts, but not required to understand the underlying physics of a steady flow field. This is because the results of the more traditional tools like iso-surfaces, cuts and streamlines were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of much interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one 'snap-shot' of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments like pV3). And methods must be developed to abstract the feature and display it in a manner that physically makes sense. The following is a list of the important physical phenomena found in transient (and steady-state) fluid flow: Shocks; Vortex ores; Regions of Recirculation; Boundary Layers; Wakes.

  8. Stability Test for Transient-Temperature Calculations

    NASA Technical Reports Server (NTRS)

    Campbell, W.

    1984-01-01

    Graphical test helps assure numerical stability of calculations of transient temperature or diffusion in composite medium. Rectangular grid forms basis of two-dimensional finite-difference model for heat conduction or other diffusion like phenomena. Model enables calculation of transient heat transfer among up to four different materials that meet at grid point.

  9. Accurate measurement of unsteady state fluid temperature

    NASA Astrophysics Data System (ADS)

    Jaremkiewicz, Magdalena

    2016-07-01

    In this paper, two accurate methods for determining the transient fluid temperature were presented. Measurements were conducted for boiling water since its temperature is known. At the beginning the thermometers are at the ambient temperature and next they are immediately immersed into saturated water. The measurements were carried out with two thermometers of different construction but with the same housing outer diameter equal to 15 mm. One of them is a K-type industrial thermometer widely available commercially. The temperature indicated by the thermometer was corrected considering the thermometers as the first or second order inertia devices. The new design of a thermometer was proposed and also used to measure the temperature of boiling water. Its characteristic feature is a cylinder-shaped housing with the sheath thermocouple located in its center. The temperature of the fluid was determined based on measurements taken in the axis of the solid cylindrical element (housing) using the inverse space marching method. Measurements of the transient temperature of the air flowing through the wind tunnel using the same thermometers were also carried out. The proposed measurement technique provides more accurate results compared with measurements using industrial thermometers in conjunction with simple temperature correction using the inertial thermometer model of the first or second order. By comparing the results, it was demonstrated that the new thermometer allows obtaining the fluid temperature much faster and with higher accuracy in comparison to the industrial thermometer. Accurate measurements of the fast changing fluid temperature are possible due to the low inertia thermometer and fast space marching method applied for solving the inverse heat conduction problem.

  10. Transient response of high temperature PEM fuel cell

    NASA Astrophysics Data System (ADS)

    Peng, J.; Shin, J. Y.; Song, T. W.

    A transient three-dimensional, single-phase and non-isothermal numerical model of polymer electrolyte membrane (PEM) fuel cell with high operating temperature has been developed and implemented in computational fluid dynamic (CFD) code. The model accounts for transient convective and diffusive transport, and allows prediction of species concentration. Electrochemical charge double-layer effect is considered. Heat generation according to electrochemical reaction and ohmic loss are involved. Water transportation across membrane is ignored due to low water electro-osmosis drag force of polymer polybenzimidazole (PBI) membrane. The prediction shows transient in current density which overshoots (undershoots) the stabilized state value when cell voltage is abruptly decreased (increased). The result shows that the peak of overshoot (undershoot) is related with cathode air stoichiometric mass flow rate instead of anode hydrogen stoichiometric mass flow rate. Current is moved smoothly and there are no overshoot or undershoot with the influence of charge double-layer effect. The maximum temperature is located in cathode catalyst layer and both fuel cell average temperature and temperature deviation are increased with increasing of current load.

  11. Finite element solution of transient fluid-structure interaction problems

    NASA Technical Reports Server (NTRS)

    Everstine, Gordon C.; Cheng, Raymond S.; Hambric, Stephen A.

    1991-01-01

    A finite element approach using NASTRAN is developed for solving time-dependent fluid-structure interaction problems, with emphasis on the transient scattering of acoustic waves from submerged elastic structures. Finite elements are used for modeling both structure and fluid domains to facilitate the graphical display of the wave motion through both media. For the liquid, the use of velocity potential as the fundamental unknown results in a symmetric matrix equation. The approach is illustrated for the problem of transient scattering from a submerged elastic spherical shell subjected to an incident tone burst. The use of an analogy between the equations of elasticity and the wave equation of acoustics, a necessary ingredient to the procedure, is summarized.

  12. Transient elasticity and polymeric fluids: Small-amplitude deformations.

    PubMed

    Müller, Oliver; Liu, Mario; Pleiner, Harald; Brand, Helmut R

    2016-02-01

    Transient elasticity (TE) is a concept useful for a systematic generalization of viscoelasticity. Due to its thermodynamic consistency, it naturally leads to a simple description of non-Newtonian effects displayed by polymeric fluids, granular media, and other soft matter. We employ a continuum-mechanical theory that is derived from TE and tailored to polymeric fluids, showing how it captures a surprisingly large number of phenomena in shear and elongational flows, including stationary, oscillatory, and transient ones, as well as the flow down an inclined channel. Even the Weissenberg effect is well accounted for. This theory is applicable for small- as well as large-amplitude deformations. We concentrate on the former in the present article, leaving the latter to a companion article. PMID:26986419

  13. TRUMP. Transient & S-State Temperature Distribution

    SciTech Connect

    Elrod, D.C.; Turner, W.D.

    1992-03-03

    TRUMP solves a general nonlinear parabolic partial differential equation describing flow in various kinds of potential fields, such as fields of temperature, pressure, or electricity and magnetism; simultaneously, it will solve two additional equations representing, in thermal problems, heat production by decomposition of two reactants having rate constants with a general Arrhenius temperature dependence. Steady-state and transient flow in one, two, or three dimensions are considered in geometrical configurations having simple or complex shapes and structures. Problem parameters may vary with spatial position, time, or primary dependent variables, temperature, pressure, or field strength. Initial conditions may vary with spatial position, and among the criteria that may be specified for ending a problem are upper and lower limits on the size of the primary dependent variable, upper limits on the problem time or on the number of time-steps or on the computer time, and attainment of steady state.

  14. Numerical Modeling of Fluid Transient in Cryogenic Fluid Network of Rocket Propulsion System

    NASA Technical Reports Server (NTRS)

    Majumdar, Alok; Flachbart, Robin

    2003-01-01

    Fluid transients, also known as water hammer, can have a significant impact on the design and operation of both spacecraft and launch vehicles propulsion systems. These transients often occur at system activation and shut down. For ground safety reasons, many spacecrafts are launched with the propellant lines dry. These lines are often evacuated by the time the spacecraft reaches orbit. When the propellant isolation valve opens during propulsion system activation, propellant rushes into lines creating a pressure surge. During propellant system shutdown, a pressure surge is created due to sudden closure of a valve. During both activation and shutdown, pressure surges must be predicted accurately to ensure structural integrity of the propulsion system fluid network. The method of characteristics is the most widely used method of calculating fluid transients in pipeline [ 1,2]. The method of characteristics, however, has limited applications in calculating flow distribution in complex flow circuits with phase change, heat transfer and rotational effects. A robust cryogenic propulsion system analyzer must have the capability to handle phase change, heat transfer, chemical reaction, rotational effects and fluid transients in conjunction with subsystem flow model for pumps, valves and various pipe fittings. In recent years, such a task has been undertaken at Marshall Space Flight Center with the development of the Generalized Fluid System Simulation Program (GFSSP), which is based on finite volume method in fluid network [3]. GFSSP has been extensively verified and validated by comparing its predictions with test data and other numerical methods for various applications such as internal flow of turbo-pump [4], propellant tank pressurization [5,6], chilldown of cryogenic transfer line [7] and squeeze film damper rotordynamics [8]. The purpose of the present paper is to investigate the applicability of the finite volume method to predict fluid transient in cryogenic flow

  15. Configurational temperature profile in confined fluids. II. Molecular fluids

    NASA Astrophysics Data System (ADS)

    Delhommelle, Jerome; Evans, Denis J.

    2001-04-01

    In an earlier paper, we applied configurational expressions of the temperature to the calculation of temperature profiles within a confined atomic fluid. This paper focuses on the application of these expressions to confined molecular fluids using ethane and hexane as examples. We first give configurational expressions for the temperature for these constrained systems. The configurational temperature profiles so obtained are compared to the kinetic temperature calculated using the equipartition principle, in equilibrium systems. These expressions are then used in nonequilibrium molecular dynamics (NEMD) simulations of fluids undergoing planar Poiseuille flow. We show that these configurational expressions provide a direct and accurate determination of the temperature profile for these systems.

  16. Scaling temperature dependent rheology of magnetorheological fluids

    NASA Astrophysics Data System (ADS)

    Sherman, Stephen G.; Powell, Louise A.; Becnel, Andrew C.; Wereley, Norman M.

    2015-05-01

    Magnetorheological (MR) fluids are suspensions of micron-scale magnetizable particles suspended in a carrier fluid. When field is applied, MR fluids develop a field controllable yield stress and a field independent post-yield viscosity. However, this viscosity has substantial temperature dependence, varying by up to an order of magnitude over the operating temperature range of MR fluid devices. We apply non-Brownian suspension theory to explain this result and find that the majority of this effect should be caused by the temperature dependent behavior of the carrier fluid. Thus, if two fluids share the same carrier fluid, then their fluid properties should scale in temperature similarly. This result is first validated by measuring viscosity across temperature for custom model fluids designed to conform to theory, showing temperature scaling within 5% for both the MR fluids and their carrier fluid. Then, on a series of related commercially available fluids with unknown additive content, we show that the MR fluids exhibit common scaling to within 4%. We also investigate the effects of magnetic hysteresis and find that it induces a negligible increase in yield stress and no measurable change in viscosity. We conclude that our non-dimensional analysis enables the temperature dependence of novel MR fluids to be characterized with fewer experiments.

  17. Application of a Differential Transform Method to the Transient Natural Convection Problem in a Vertical Tube with Variable Fluid Properties

    NASA Astrophysics Data System (ADS)

    Chiba, Ryoichi

    2016-02-01

    The transient natural convection of a viscous fluid in a heated vertical tube is studied using the two-dimensional differential transform method (DTM). A time-dependent Dirichlet boundary condition is imposed for tube wall temperature. The partial differential equations for the velocity and temperature fields within the tube are solved by the DTM while considering temperature-dependent viscosity and thermal conductivity of the fluid. As a result, tractable solutions in double-series form are derived for the temperature and flow velocity. The transformed functions included in the solutions are obtained through a simple recursive procedure. Numerical results illustrate the effects of temperature-dependent properties on transient temperature and flow behaviour, including the Nusselt number and volumetric flow rate. The DTM gives accurate series solutions without any special functions for nonlinear transient heat transfer problems which are advantageous in finding the derivative or integral.

  18. Nanoscale transient porosity controls large-scale metamorphic fluid flow

    NASA Astrophysics Data System (ADS)

    Plümper, Oliver; Botan, Alexandru; Los, Catharina; Malthe-Sørenssen, Anders; Jamtveit, Bjørn

    2016-04-01

    investigations we used non-equilibrium thermodynamics and molecular dynamics simulations to investigate the influence of nanoscale pore transport phenomena on metamorphic mineral replacement reactions. Our findings suggest that fluid transport through nanoscale transient pore networks may control regional-scale metamorphism and metasomatism, at least in the feldspar-dominated crust.

  19. Network Flow Simulation of Fluid Transients in Rocket Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Bandyopadhyay, Alak; Hamill, Brian; Ramachandran, Narayanan; Majumdar, Alok

    2011-01-01

    Fluid transients, also known as water hammer, can have a significant impact on the design and operation of both spacecraft and launch vehicle propulsion systems. These transients often occur at system activation and shutdown. The pressure rise due to sudden opening and closing of valves of propulsion feed lines can cause serious damage during activation and shutdown of propulsion systems. During activation (valve opening) and shutdown (valve closing), pressure surges must be predicted accurately to ensure structural integrity of the propulsion system fluid network. In the current work, a network flow simulation software (Generalized Fluid System Simulation Program) based on Finite Volume Method has been used to predict the pressure surges in the feed line due to both valve closing and valve opening using two separate geometrical configurations. The valve opening pressure surge results are compared with experimental data available in the literature and the numerical results compared very well within reasonable accuracy (< 5%) for a wide range of inlet-to-initial pressure ratios. A Fast Fourier Transform is preformed on the pressure oscillations to predict the various modal frequencies of the pressure wave. The shutdown problem, i.e. valve closing problem, the simulation results are compared with the results of Method of Characteristics. Most rocket engines experience a longitudinal acceleration, known as "pogo" during the later stage of engine burn. In the shutdown example problem, an accumulator has been used in the feed system to demonstrate the "pogo" mitigation effects in the feed system of propellant. The simulation results using GFSSP compared very well with the results of Method of Characteristics.

  20. Groundwater temperature transients on the Armutlu peninsula, eastern Marmara region

    NASA Astrophysics Data System (ADS)

    Woith, Heiko; Caka, Deniz; Seyis, Cemil; Italiano, Francesco; Celik, Cengiz; Wang, Rongjiang; Baris, Serif

    2016-04-01

    Since many years MAM and GFZ in co-operation with Kocaeli University (KU) operate fluid monitoring stations around the Sea of Marmara. In the frame of MARsite (MARsite has received funding from the European Union's Seventh Programme for research, technological development and demonstration under grant agreement No 308417) these networks were jointly evaluated for the first time. The on-land fluid monitoring networks continuously monitor the following parameters: soil radon (21 sites), temperature and conductivity of thermal springs (9 sites) operated by MAM covering the whole Marmara region; fluid pressure and water level/temperature (8 sites) within ARNET operated by GFZ/KU. ARNET is a combined seismological/hydrogeological monitoring network covering the Armutlu peninsula located SE of Istanbul. Additional to the geothermal wells and springs - our main target to detect transients of potentially seismo-tectonic origin - three shallow groundwater wells (tenth of meters deep) are being operated to identify and quantify seasonal variations, and meteorological influences like rainfall and snowmelt. But it turned out that these shallow aquifer systems showed very stable conditions with very small annual temperature amplitudes (0.2 - 0.3°C). One of these shallow monitoring wells is located just south of Lake Iznik (in the village of Sölöz) very close to the southern branch of the North Anatolian Fault Zone. Water level showed a steady decreasing trend since June 2012. This trend resulted in a data gap starting in January 2014, when the water level dropped below the sensor position. After adjusting the sensor position, positive spikes in the borehole temperature were recorded in June and August 2014, and again in 2015. The spikes are characterised by a sharp temperature increase followed by a decay lasting several days until the pre-event temperature was reached again. Since the spikes occurred on two independent logger systems, and since they lasted several days, a

  1. Temperature controller for a fluid cooled garment

    NASA Technical Reports Server (NTRS)

    Chambers, A. B.; Blackaby, J. R.; Billingham, J. (Inventor)

    1973-01-01

    An automatic controller for controlling the inlet temperature of the coolant to a fluid cooled garment without requiring skin sensors is described. Temperature is controlled by the wearer's evaporative water loss rate.

  2. Temperature stability and durability of MR fluids

    NASA Astrophysics Data System (ADS)

    Zhang, Ping; Tang, Long; Yue, En; Luo, Shun-An; Zhao, Guang-ming

    2012-04-01

    Temperature stability and durability of magnetorheological fluids are important for engineering application. The damper with magnetorheological fluids were put in environment of -40°C to 130°C and the forces were measured under different currents. Durability was evaluated by performance experiments of 2×106, 3.5×106,and 5×106 cycles. The results show that magnetorheological fluids have ideal temperature stability and durability.

  3. Temperature stability and durability of MR fluids

    NASA Astrophysics Data System (ADS)

    Zhang, Ping; Tang, Long; Yue, En; Luo, Shun-An; Zhao, Guang-ming

    2011-11-01

    Temperature stability and durability of magnetorheological fluids are important for engineering application. The damper with magnetorheological fluids were put in environment of -40°C to 130°C and the forces were measured under different currents. Durability was evaluated by performance experiments of 2×106, 3.5×106,and 5×106 cycles. The results show that magnetorheological fluids have ideal temperature stability and durability.

  4. Imaging hydraulic fractures using temperature transients in the Belridge Diatomite

    SciTech Connect

    Shahin, G.T.; Johnston, R.M.

    1995-12-31

    Results of a temperature transient analysis of Shell`s Phase 1 and Phase 2 Diatomite Steamdrive Pilots are used to image hydraulic injection fracture lengths, angles, and heat injectivities into the low-permeability formation. The Phase 1 Pilot is a limited-interval injection test. In Phase 2, steam is injected into two 350 ft upper and lower zones through separate hydraulic fractures. Temperature response of both pilots is monitored with sixteen logging observation wells. A perturbation analysis of the non-linear pressure diffusion and heat transport equations indicates that at a permeability of about 0.1 md or less, heat transport in the Diatomite tends to be dominated by thermal diffusivity, and pressure diffusion is dominated by the ratio of thermal expansion to fluid compressibility. Under these conditions, the temperature observed at a logging observation well is governed by a dimensionless quantity that depends on the perpendicular distance between the observation well and the hydraulic fracture, divided by the square root of time. Using this dependence, a novel method is developed for imaging hydraulic fracture geometry and relative heat injectivity from the temperature history of the pilot.

  5. Configurational temperature profile in confined fluids. I. Atomic fluid

    NASA Astrophysics Data System (ADS)

    Delhommelle, Jerome; Evans, Denis J.

    2001-04-01

    Two configurational expressions for the temperature are applied to the calculation of temperature profiles within a confined atomic fluid in a narrow slit pore. The configurational temperatures profiles so obtained are compared to the kinetic temperature, calculated from the equipartition principle, in equilibrium (EMD), and nonequilibrium molecular dynamics (NEMD) simulations of planar Poiseuille flow. We show that one of the configurational expressions exhibits a system-size dependence which prevents its application to the determination of high-resolution temperature profiles. The other expression yields good agreement with the kinetic temperature profile in both equilibrium and nonequilibrium systems.

  6. Transient Thermal Model and Analysis of the Lunar Surface and Regolith for Cryogenic Fluid Storage

    NASA Technical Reports Server (NTRS)

    Christie, Robert J.; Plachta, David W.; Yasan, Mohammad M.

    2008-01-01

    A transient thermal model of the lunar surface and regolith was developed along with analytical techniques which will be used to evaluate the storage of cryogenic fluids at equatorial and polar landing sites. The model can provide lunar surface and subsurface temperatures as a function of latitude and time throughout the lunar cycle and season. It also accounts for the presence of or lack of the undisturbed fluff layer on the lunar surface. The model was validated with Apollo 15 and Clementine data and shows good agreement with other analytical models.

  7. Transient Thermo-fluid Model of Meniscus Behavior and Slag Consumption in Steel Continuous Casting

    NASA Astrophysics Data System (ADS)

    Jonayat, A. S. M.; Thomas, Brian G.

    2014-10-01

    The behavior of the slag layer between the oscillating mold wall, the slag rim, the slag/liquid steel interface, and the solidifying steel shell, is of immense importance for the surface quality of continuous-cast steel. A computational model of the meniscus region has been developed, that includes transient heat transfer, multi-phase fluid flow, solidification of the slag, and movement of the mold during an oscillation cycle. First, the model is applied to a lab experiment done with a "mold simulator" to verify the transient temperature-field predictions. Next, the model is verified by matching with available literature and plant measurements of slag consumption. A reasonable agreement has been observed for both temperature and flow-field. The predictions show that transient temperature behavior depends on the location of the thermocouple during the oscillation relative to the meniscus. During an oscillation cycle, heat transfer variations in a laboratory frame of reference are more severe than experienced by the moving mold thermocouples, and the local heat transfer rate is increased greatly when steel overflows the meniscus. Finally, the model is applied to conduct a parametric study on the effect of casting speed, stroke, frequency, and modification ratio on slag consumption. Slag consumption per unit area increases with increase of stroke and modification ratio, and decreases with increase of casting speed while the relation with frequency is not straightforward. The match between model predictions and literature trends suggests that this methodology can be used for further investigations.

  8. Inference of permeability heterogeneity from joint inversion of transient flow and temperature data

    NASA Astrophysics Data System (ADS)

    Zhang, Zhishuai; Jafarpour, Behnam; Li, Lianlin

    2014-06-01

    Characterization of the rock permeability distribution in compartmentalized deep aquifers, enhanced geothermal systems, and hydrocarbon reservoirs is important for predicting the flow and transport behavior in these formations. Reliable prediction of the fluid flow and transport processes can, in turn, lead to effective development of the subsurface energy and environmental resources. In deep formations where thermal gradients are significant, the transient temperature data can provide valuable information about the permeability distribution with depth and about the vertical fluid displacement. This paper examines the importance of temperature data in resolving the distribution of permeability with depth by jointly, and individually, integrating the transient temperature and flow data. We demonstrate that when estimating permeability distributions in deep geothermal reservoirs, incorporating temperature data can increase the resolution of the permeability distribution profile with depth. To illustrate the importance of temperature measurements, we adopt a coupled transient heat and fluid flow as a forward model to predict the heat and fluid transport in a geothermal reservoir and develop an adjoint model for efficient computation of the gradient information for model calibration. We perform a series of numerical experiments for integration of flow and pressure data alone, temperature data alone, and flow and pressure jointly with temperature data. In each case, we apply the maximum A-posteriori (MAP) method and the randomized maximum likelihood (RML) method for inversion and uncertainty quantification. Analysis of the sensitivity of temperature and production data to heterogeneous permeability distributions reveals that the temperature of fluid, even when measured at the surface, is sensitive to the permeability distribution in the vertical extent of the reservoir. Hence, temperature measurements can be augmented with flow-related data to enhance the resolution of

  9. Low temperature breakers for gelled fracturing fluids

    SciTech Connect

    Syrinek, A.R.; Lyon, L.B.

    1989-01-03

    A method is described for breaking gelled viscosities of oil-based gelled fracturing fluids containing a gellant comprising aluminum complexes of alkyl phosphate esters and a proppant. The fracturing fluids are used in low-temperature formations having operating temperatures ranging between 60/sup 0/ - 120/sup 0/F. The oil-based gelled fracturing fluids are treated with an effective viscosity breaking amount of a chemical breaker consisting essentially of an admixture of hydrated lime and sodium bicarbonate containing a weight ratio ranging between 100/0 to about 20/80 hydrated lime to sodium bicarbonate.

  10. Plasma-Catalysis During Temperature Transient Testing

    SciTech Connect

    Hoard, John

    2001-08-05

    A combination of catalysts is used together with nonthermal plasma in simulated diesel exhaust, while the gas temperature is varied. The catalysts both store and convert pollutants. As a result, pollutant concentrations during temperature ramps are different than those at steady state conditions. The data are presented for plasma followed by BaY, alumina, and Pt catalysts in simulated exhaust. When temperature ramps from high to low, apparent NOx conversion is quite high. However, when temperature is ramped from low to high, lower apparent conversions are seen. In a typical test cycle, average NOx conversion between 100 and 400 C is 60%. Peak conversion during the down ramp is over 90%, and minimum conversion during the up ramp is 30%. The composition of the effluent gas also varies during the temperature cycle. Intermediates such as methyl nitrate and hydrogen cyanide are not present following the combination of catalysts.

  11. Intermediate Temperature Fluids Life Tests - Experiments

    NASA Technical Reports Server (NTRS)

    Anderson, William G.; Bonner, Richard W.; Dussinger, Peter M.; Hartenstine, John R.; Sarraf, David B.; Locci, Ivan E.

    2007-01-01

    There are a number of different applications that could use heat pipes or loop heat pipes (LHPs) in the intermediate temperature range of 450 to 725 K (170 to 450 C), including space nuclear power system radiators, fuel cells, and high temperature electronics cooling. Historically, water has been used in heat pipes at temperatures up to about 425 K (150 C). Recent life tests, updated below, demonstrate that titanium/water and Monel/water heat pipes can be used at temperatures up to 550 K (277 C), due to water's favorable transport properties. At temperatures above roughly 570 K (300 C), water is no longer a suitable fluid, due to high vapor pressure and low surface tension as the critical point is approached. At higher temperatures, another working fluid/envelope combination is required, either an organic or halide working fluid. An electromotive force method was used to predict the compatibility of halide working fluids with envelope materials. This procedure was used to reject aluminum and aluminum alloys as envelope materials, due to their high decomposition potential. Titanium and three corrosion resistant superalloys were chosen as envelope materials. Life tests were conducted with these envelopes and six different working fluids: AlBr3, GaCl3, SnCl4, TiCl4, TiBr4, and eutectic diphenyl/diphenyl oxide (Therminol VP-1/Dowtherm A). All of the life tests except for the GaCl3 are ongoing; the GaCl3 was incompatible. As the temperature approaches 725 K (450 C), cesium is a potential heat pipe working fluid. Life tests results are also presented for cesium/Monel 400 and cesium/70-30 copper/nickel heat pipes operating near 750 K (477 C). These materials are not suitable for long term operation, due to copper transport from the condenser to the evaporator.

  12. Transient dynamics of a colloidal particle driven through a viscoelastic fluid

    NASA Astrophysics Data System (ADS)

    Ruben Gomez-Solano, Juan; Bechinger, Clemens

    2015-10-01

    We study the transient motion of a colloidal particle actively dragged by an optical trap through different viscoelastic fluids (wormlike micelles, polymer solutions, and entangled λ-phage DNA). We observe that, after sudden removal of the moving trap, the particle recoils due to the recovery of the deformed fluid microstructure. We find that the transient dynamics of the particle proceeds via a double-exponential relaxation, whose relaxation times remain independent of the initial particle velocity whereas their amplitudes strongly depend on it. While the fastest relaxation mirrors the viscous damping of the particle by the solvent, the slow relaxation results from the recovery of the strained viscoelastic matrix. We show that this transient information, which has no counterpart in Newtonian fluids, can be exploited to investigate linear and nonlinear rheological properties of the embedding fluid, thus providing a novel method to perform transient rheology at the micron-scale.

  13. Fracturing fluids for low temperature wells

    SciTech Connect

    Montgomery, C.T.; Dollarhide, F.E.

    1980-01-01

    Highly viscous fluids are used to initiate and propagate fractures and to place proppant in the fractures during the hydraulic stimulation process. These fluids can cause damage to the conductivity of the induced fractures if they are not properly cleaned out after the fracturing treatment. The clean-up process is aided by the degradation of the polymers, and in low temperature wells the breakdown of the polymer must be chemically induced. This work presents data on a new fracturing fluid aimed specifically at stimulating low temperature and low pressure reservoirs. The system consists of a CO/sub 2/-energized, cross-linked hydroxypropyl guar fluid. The gel is degraded by a traditional breaker that is activated by a new, low temperature breaker activator. The fluid is effective in wells as cool as 60 F and with bhp as low as 100 psi and should be particularly applicable to the shallow gas wells in the Alberta Medicine Hat and high level Keg River areas.

  14. Restricted versus Standard Maintenance Fluid Volume in Management of Transient Tachypnea of Newborn: A Clinical Trial

    PubMed Central

    Dehdashtian, Masoud; Aramesh, Mohammad-Reza; Melekian, Arash; Aletayeb, Mohammad-Hasan; Ghaemmaghami, Anahita

    2014-01-01

    Objective: The incidence of Transient Tachypnea of Newborn (TTN) is higher in infants born by cesarean section than with  vaginal delivery. Treatment of transient tachypnea of newborn is supportive. The purpose of this study was to assess the effect of restricted fluid volume intake on the course of respiratory distress in patients with TTN. Methods: This is a quasi-experimental clinical trial of 83 neonates diagnosed with TTN admitted to a neonatal intensive care unit in south west Iran. In this study the effect of restriction of maintenance fluid volume in the course of respiratory distress in newborns with transient tachypnea was assessed. Findings: In the standard fluid volume intake group 18 (42.8%) cases needed nasal continuous positive airway pressure (NCPAP) and one (2.38%) case mechanical ventilation, and in restricted fluid volume intake group 13 (32.5%) cases needed NCPAP and two (5%) cases mechanical ventilation. 54.82% of cases were supported with oxyhood in the standard fluid volume and 62.5% in the restricted fluid volume intake group. Differences in duration of the needed NCPAP and oxygen hood between the two groups were significant. Fluid restriction had no adverse effect on the urine specific gravity or weight loss of the studied newborns. Conclusion: Limited fluid administered to newborns with transient tachypnea of newborn is safe and resulted in shorter duration of respiratory support. PMID:25793064

  15. Micromechanical transient sensor for measuring viscosity and density of a fluid

    DOEpatents

    Thundat, Thomas G.; Oden, Patrick I.; Warmack, Robert J.; Finot, Eric Laurent

    2001-01-01

    A method and apparatus for measuring the viscosity and/or specific density of a fluid utilizes a microcantilever vibrated in the analyte fluid. The source of vibration is switched on and off and the transient behavior or decay in amplitude of the vibration is monitored. The method is particularly useful for the measurement of process conditions in remote locations in real time.

  16. Fluid-Rock Dynamic Interaction in Magmatic Conduits: Modelling Transients Using an Analytical Solution

    NASA Astrophysics Data System (ADS)

    Arciniega-Ceballos, Alejandra; Scheu, Bettina; Sanchez-Sesma, Francisco; Dingwell, Donald

    2014-05-01

    We compute transients fluid-rock dynamic interaction in a fluid driven axisymmetric conduit embedded in an infinite, homogeneous elastic space. Both fluid and solid are dynamically coupled fulfilling continuity of velocities and radial stresses at the conduit's wall. The calculation model considers the viscosity as a key parameter leading to non-linear scheme. A pressure transient at a point of the conduit, that perturbs a steady flow of incompressible viscous fluid, produces the interaction between the fluid and motion at the conduit's walls. The fluid motion induces the elastic response of the conduit forcing it to oscillate radially. The fluid-filled conduit dynamics is governed by three second-order, ordinary non-linear differential equations, which are solved numerically by applying a fifth-order Runge-Kutta scheme. Boundary conditions satisfy the Bernoulli's principle allowing coupling several pipe segments which may present smooth variation in fluid properties. The nature of the source involves different pressure excitations functions including those measuring during simulations of gas burst and fragmentation of volcanic rocks under controlled laboratory conditions. Far-field velocity synthetics radiated by motion of the conduit's walls and fluid flows ascending to the surface, display characteristic waveforms and frequency content that are similar to those of long-period signals and tremor observed at active volcanoes. Results suggest that transient fluid flow induced oscillations may explain long-period and tremor signals. Advantages and limitations of this approach are discussed.

  17. Intermediate Temperature Fluids Life Tests - Theory

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Sarraf, David B.; Locci, Ivan E.; Anderson, William G.

    2008-01-01

    There are a number of different applications that could use heat pipes or loop heat pipes (LHPs) in the intermediate temperature range of 450 to 750 K, including space nuclear power system radiators, and high temperature electronics cooling. Potential working fluids include organic fluids, elements, and halides, with halides being the least understood, with only a few life tests conducted. Potential envelope materials for halide working fluids include pure aluminum, aluminum alloys, commercially pure (CP) titanium, titanium alloys, and corrosion resistant superalloys. Life tests were conducted with three halides (AlBr3, SbBr3, and TiCl4) and water in three different envelopes: two aluminum alloys (Al-5052, Al-6061) and Cp-2 titanium. The AlBr3 attacked the grain boundaries in the aluminum envelopes, and formed TiAl compounds in the titanium. The SbBr3 was incompatible with the only envelope material that it was tested with, Al-6061. TiCl4 and water were both compatible with CP2-titanium. A theoretical model was developed that uses electromotive force differences to predict the compatibility of halide working fluids with envelope materials. This theory predicts that iron, nickel, and molybdenum are good envelope materials, while aluminum and titanium halides are good working fluids. The model is in good agreement with results form previous life tests, as well as the current life tests.

  18. Numerical simulation of transient temperature field during laser keyhole welding of 304 stainless steel sheet

    NASA Astrophysics Data System (ADS)

    Wang, Renping; Lei, Yongping; Shi, Yaowu

    2011-06-01

    A three-dimensional transient numerical model was developed to study the temperature field and molten pool shape during continuous laser keyhole welding. The volume-of-fluid (VOF) method was employed to track free surfaces. Melting and evaporation enthalpy, recoil pressure, surface tension, and energy loss due to evaporating materials were considered in this model. The enthalpy-porosity technique was employed to account for the latent heat during melting and solidification. Temperature fields and weld pool shape were calculated using FLUENT software. The calculated weld dimensions agreed reasonable well with the experimental results. The effectiveness of the developed computational procedure had been confirmed.

  19. Ignition transient analysis of a solid rocket motor using a one dimensional two fluid model

    NASA Astrophysics Data System (ADS)

    Pardue, Byron A.; Han, Samuel S.

    1992-07-01

    A one dimensional two fluid numerical model has been used to study the ignition transient stage of a Space Shuttle solid rocket motor. During the ignition phase of a solid rocket motor a pressure transient is induced by complex transport processes involving the igniter gas heat transfer to the propellant, chemical reactions at the propellant surface, and the interaction of the fluid with the attached rocket nozzle. One dimensional models used in the past neglected the aluminum oxide particles which are present in the combustion gases. The current model uses the IPSA (Inter-Phase-Slip-Algorithm) to solve the transient compressible flow equations for the rocket chamber and attached nozzle. Numerical results for head end pressure changes and overall thrust are compared with both measurement data and predictions of a one dimensional one fluid model.

  20. FLUID TRANSIENTS IN A PIPELINE WITH ONE END OPEN

    SciTech Connect

    Leishear, R

    2008-06-09

    Water hammer during multi-phase flow is rather complex, but in some cases an upper limit to the pressure surge magnitude during water hammer can be estimated. In the case considered here, a two mile long pipeline with a single high point was permitted to partially drain. Due to gravitational effects, air bubbles up through the pipe line to its highest point, but the time required for air to reach the top of the pipe is rather long. Consequently, some transients caused by valve operations are affected by air entrapment and some are not. The intent of this research was to investigate the complex interactions between air, water vapor, and liquid during water hammer in a long pipe with one end of the pipe open to atmospheric conditions. To understand the system dynamics, experimental data was obtained from a long pipeline with an open end and also from a short, transparent tube. Transient calculations were performed for valve closures and pump operations as applicable. The limitations of available calculation techniques were considered in detail.

  1. Modeling quantum fluid dynamics at nonzero temperatures

    PubMed Central

    Berloff, Natalia G.; Brachet, Marc; Proukakis, Nick P.

    2014-01-01

    The detailed understanding of the intricate dynamics of quantum fluids, in particular in the rapidly growing subfield of quantum turbulence which elucidates the evolution of a vortex tangle in a superfluid, requires an in-depth understanding of the role of finite temperature in such systems. The Landau two-fluid model is the most successful hydrodynamical theory of superfluid helium, but by the nature of the scale separations it cannot give an adequate description of the processes involving vortex dynamics and interactions. In our contribution we introduce a framework based on a nonlinear classical-field equation that is mathematically identical to the Landau model and provides a mechanism for severing and coalescence of vortex lines, so that the questions related to the behavior of quantized vortices can be addressed self-consistently. The correct equation of state as well as nonlocality of interactions that leads to the existence of the roton minimum can also be introduced in such description. We review and apply the ideas developed for finite-temperature description of weakly interacting Bose gases as possible extensions and numerical refinements of the proposed method. We apply this method to elucidate the behavior of the vortices during expansion and contraction following the change in applied pressure. We show that at low temperatures, during the contraction of the vortex core as the negative pressure grows back to positive values, the vortex line density grows through a mechanism of vortex multiplication. This mechanism is suppressed at high temperatures. PMID:24704874

  2. Measurement of the thermal properties of electrically conducting fluids using coated transient hot wires

    SciTech Connect

    Perkins, R.A.

    1994-12-31

    Measurements of fluid thermal properties using the transient hot-wire technique are described. When bare hot wires are used in electrically conducting fluids there are additional measurement uncertainties due to the formation of electric double layers on the surfaces of the wires and the cell wall. If the electrical conductivity of the fluid is large enough there is also significant power generation in the fluid. These measurement uncertainties can be eliminated by electrically insulating the hot wires with a thin film. The use of tantalum hot wires with an anodized layer of tantalum pentoxide is demonstrated with measurements on nonpolar argon and polar 1,1,1,2 tetrafluoroethane (R134a). Although coated tantalum hot wires have been used previously in a transient mode to measure the thermal conductivity of liquids, this work is the first demonstration of the use of coated wires to measure thermal conductivity in the liquid, vapor, and supercritical gas phases.

  3. Measurement of the thermal properties of electrically conducting fluids using coated transient hot wires

    SciTech Connect

    Perkins, R.A.

    1994-09-01

    Measurements of fluid thermal properties using the transient hot-wire technique are described. When bare hot wires are used in electrically conducting fluids there are additional measurement uncertainties due to the formation of electric double layers on the surfaces of the wires and the cell wall. If the electrical conductivity of the fluid is large enough there is also significant power generation in the fluid. These measurement uncertainties can be eliminated by electrically insulating the hot wires with a thin film. The use of tantalum hot wires with an anodized layer of tantalum pentoxide is demonstrated with measurements on nonpolar argon and polar 1,1,1,2 tetrafluorethane (R134a). Although coated tantalum hot wires have been used previously in a transient mode to measure the thermal conductivity of liquids, this work is the first demonstration of the use of coated wires to measure thermal conductivity in the liquid, vapor, and supercritical gas phases.

  4. Thermal stresses in the wall of pipes caused by periodic change of temperature of medium fluid

    NASA Astrophysics Data System (ADS)

    Atefi, Gholamali; Mahmoudi, Hamid

    2012-06-01

    The problem of thermal stresses induced in pipes due to periodic change of medium fluid temperature has never been considered completely. In this paper an analytical solution for obtaining thermal stresses in a pipe caused by periodic time varying of temperature of medium fluid is offered. Transient heat conduction equation in cylindrical coordinates for a long hollow cylinder under periodic change of ambient temperature condition is solved analytically using Fourier series and Temperature distribution in the wall of pipe as a function of time and radial direction is specified. Then resulting thermal stresses are obtained using thermoelasticity relations. Because of the use of Fourier series expansion in obtaining the transient temperature field the proposed method is very comprehensive and covers many theoretical and practical problems. The results for thermal stresses have been compared with former works and show excellent agreement for the same conditions.

  5. Fluid-solid coupled simulation of the ignition transient of solid rocket motor

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Liu, Peijin; He, Guoqiang

    2015-05-01

    The first period of the solid rocket motor operation is the ignition transient, which involves complex processes and, according to chronological sequence, can be divided into several stages, namely, igniter jet injection, propellant heating and ignition, flame spreading, chamber pressurization and solid propellant deformation. The ignition transient should be comprehensively analyzed because it significantly influences the overall performance of the solid rocket motor. A numerical approach is presented in this paper for simulating the fluid-solid interaction problems in the ignition transient of the solid rocket motor. In the proposed procedure, the time-dependent numerical solutions of the governing equations of internal compressible fluid flow are loosely coupled with those of the geometrical nonlinearity problems to determine the propellant mechanical response and deformation. The well-known Zeldovich-Novozhilov model was employed to model propellant ignition and combustion. The fluid-solid coupling interface data interpolation scheme and coupling instance for different computational agents were also reported. Finally, numerical validation was performed, and the proposed approach was applied to the ignition transient of one laboratory-scale solid rocket motor. For the application, the internal ballistics were obtained from the ground hot firing test, and comparisons were made. Results show that the integrated framework allows us to perform coupled simulations of the propellant ignition, strong unsteady internal fluid flow, and propellant mechanical response in SRMs with satisfactory stability and efficiency and presents a reliable and accurate solution to complex multi-physics problems.

  6. Temperature-dependent transient creep and dynamics of cratonic lithosphere

    NASA Astrophysics Data System (ADS)

    Birger, Boris I.

    2013-11-01

    Large-scale mantle convection forms the upper boundary layer (lithosphere) where the vertical temperature drop is about 1300 K. Theoretical rheology and laboratory experiments with rock samples show that transient creep occurs while creep strains are sufficiently small. The transient creep is described by the temperature-dependent Andrade rheological model. Since plate tectonics allows only small deformations in lithospheric plates, creep of the lithosphere plates is transient whereas steady-state creep, described by non-Newtonian power-law rheological model, takes place in the underlying mantle. The solution of stability problem shows that the lithosphere is stable but small-scale convective oscillations are attenuated very weakly in regions of thickened lithosphere beneath continental cratons (subcratonic roots) where the thickness of the lithosphere is about 200 km. These oscillations create small-scale convective cells (the horizontal dimensions of the cells are of the order of the subcratonic lithosphere thickness). Direction of motion within the cells periodically changes (the period of convective oscillations is of the order of 3 × 108 yr). In this study, the oscillations of cratonic lithosphere caused by initial relief perturbation are considered. This relief perturbation is assumed to be created by overthrusting in orogenic belts surrounding cratons. The perturbation of the Earth's surface relief leads to a fast isothermal process of isostatic recovery. In the presence of vertical temperature gradient, vertical displacements, associated with the recovery process in the lithosphere interior, instantly produce the initial temperature perturbations exciting thermoconvective oscillations in the cratonic lithosphere. These small-amplitude convective oscillations cause oscillatory crustal movements which form sedimentary basins on cratons.

  7. Transient growth in Taylor-Couette flow of a Bingham fluid

    NASA Astrophysics Data System (ADS)

    Chen, Cheng; Wan, Zhen-Hua; Zhang, Wei-Guo

    2015-04-01

    In this paper we investigate linear transient growth of perturbation energy in Taylor-Couette flow of a Bingham fluid. The effects of yield stress on transient growth and the structure of the optimal perturbation are mainly considered for both the wide-gap case and the narrow-gap case. For this purpose we complement the linear stability of this flow subjected to axisymmetric disturbances, presented by Landry et al. [M. P. Landry, I. A. Frigaard, and D. M. Martinez, J. Fluid Mech. 560, 321 (2006), 10.1017/S0022112006000620], with the transient growth characteristics of both axisymmetric and nonaxisymmetric perturbations. We obtain the variations of the relative amplitude of optimal perturbation with yield stress, analyze the roles played by the Coriolis force and the additional stress in the evolution of meridional perturbations for the axisymmetric modes, and give the explanations for the possible change of the optimal azimuthal mode (featured by the maximum optimal energy growth Gopt) with yield stress. These results might help us in the understanding of the effect of fluid rheology on transient growth mechanism in vortex flows.

  8. Transient growth in Taylor-Couette flow of a Bingham fluid.

    PubMed

    Chen, Cheng; Wan, Zhen-Hua; Zhang, Wei-Guo

    2015-04-01

    In this paper we investigate linear transient growth of perturbation energy in Taylor-Couette flow of a Bingham fluid. The effects of yield stress on transient growth and the structure of the optimal perturbation are mainly considered for both the wide-gap case and the narrow-gap case. For this purpose we complement the linear stability of this flow subjected to axisymmetric disturbances, presented by Landry et al. [M. P. Landry, I. A. Frigaard, and D. M. Martinez, J. Fluid Mech. 560, 321 (2006)], with the transient growth characteristics of both axisymmetric and nonaxisymmetric perturbations. We obtain the variations of the relative amplitude of optimal perturbation with yield stress, analyze the roles played by the Coriolis force and the additional stress in the evolution of meridional perturbations for the axisymmetric modes, and give the explanations for the possible change of the optimal azimuthal mode (featured by the maximum optimal energy growth G(opt)) with yield stress. These results might help us in the understanding of the effect of fluid rheology on transient growth mechanism in vortex flows. PMID:25974605

  9. Rabbit tendon cells produce MMP-3 in response to fluid flow without significant calcium transients.

    PubMed

    Archambault, Joanne M; Elfervig-Wall, Michelle K; Tsuzaki, Mari; Herzog, Walter; Banes, Albert J

    2002-03-01

    Forces applied to tendon during movement cause cellular deformation, as well as fluid movement. The goal of this study was to test the hypothesis that rabbit tendon fibroblasts detect and respond to fluid-induced shear stress. Cells were isolated from the paratenon of the rabbit Achilles tendon and then subjected to fluid flow at 1 dyn/cm(2) for 6h in a specially designed multi-slide flow device. The application of fluid flow led to an increased expression of the collagenase-1 (MMP-1), stromelysin-1 (MMP-3), cyclooxygenase II (COX-2) and interleukin-1beta (IL-1beta) genes. The release of proMMP-3 into the medium exhibited a dose-response with the level of fluid shear stress. However, not all cells aligned in the direction of flow. In other experiments, the same cells were incubated with the calcium-reactive dye FURA-2 AM, then subjected to laminar fluid flow in a parallel plate flow chamber. The cells did not significantly increase intracellular calcium concentration when exposed to fluid shear stress levels of up to 25 dyn/cm(2). These results show that gene expression in rabbit tendon cells is sensitive to fluid flow, but that signal transduction is not dependent on intracellular calcium transients. The upregulation of the MMP-1, MMP-3 and COX-2 genes shows that fluid flow could be an important mechanical stimulus for tendon remodelling or injury. PMID:11858805

  10. Transient Middle Eocene atmospheric CO₂ and temperature variations.

    PubMed

    Bijl, Peter K; Houben, Alexander J P; Schouten, Stefan; Bohaty, Steven M; Sluijs, Appy; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S; Brinkhuis, Henk

    2010-11-01

    The long-term warmth of the Eocene (~56 to 34 million years ago) is commonly associated with elevated partial pressure of atmospheric carbon dioxide (pCO(2)). However, a direct relationship between the two has not been established for short-term climate perturbations. We reconstructed changes in both pCO(2) and temperature over an episode of transient global warming called the Middle Eocene Climatic Optimum (MECO; ~40 million years ago). Organic molecular paleothermometry indicates a warming of southwest Pacific sea surface temperatures (SSTs) by 3° to 6°C. Reconstructions of pCO(2) indicate a concomitant increase by a factor of 2 to 3. The marked consistency between SST and pCO(2) trends during the MECO suggests that elevated pCO(2) played a major role in global warming during the MECO. PMID:21051636

  11. Transient analysis and burnout of high temperature superconducting current leads

    NASA Astrophysics Data System (ADS)

    Seol, S. Y.; Hull, J. R.

    The transient behaviour of high-temperature superconductor (HTS) current leads operated between liquid helium and liquid nitrogen temperatures is analysed for burnout conditions upon transition of the HTS into the normal state. Leads composed of HTS only and of HTS sheathed by pure silver or silver alloy are investigated numerically for temperature-dependent properties and analytically for temperature-independent properties. For lower values of shape factor (current density times length), the lead can be operated indefinitely without burnout. At higher values of shape factor, the lead reaches burnout in a finite time. With high current densities, the leads heat adiabatically. For a fixed shape factor, low current densities are desired to achieve long burnout times. To achieve a low helium boil-off rate in the superconducting state without danger of burnout, there is a preferred temperature dependence for thermal conductivity, and silver alloy sheaths are preferred to pure silver sheaths. However, for a given current density, pure silver sheaths take longer to burn out.

  12. Laboratory experiments and continuous fluid monitoring at Campi Flegrei to understand pressure transients in hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Woith, Heiko; Mangiacapra, Annarita; Chiodini, Giovanni; Pilz, Marco; Walter, Thomas

    2015-04-01

    The hydrothermal system beneath Campi Flegrei is strongly affected by sub-surface processes as manifested by the existence of a geothermal "plume" below Solfatara (Bruno et al. 2007), associated with formation of new fumaroles and the spatial pattern of exhalation vents. Within the frame of MED-SUV (The MED-SUV project has received funding from the European Union Seventh Framework Programme (FP7) under Grant agreement no 308665), pressure tansients in the hydrothermal system of Campi Flegrei shall be studied using a combination of laboratory experiments and continuous pressure/temperature monitoring at fumaroles, mudpools, hot springs, and geothermal wells. Four groundwater monitoring sites were installed in September 2013: one in the Fangaia mud pool inside Solfatara and three within the geothermal area of Agnano, which is located roughly 3 km to the East of the Solfatara crater. In 2014 additional sensors were installed in Pisciarelli. Autonomous devices are being used to record the water level and water temperature at 10 minute intervals. Records reveal significant changes of the hydrothermal system in September 2013 at the Agnano main spring during the night from 23 to 24 September. Both, the water level and the water temperature dropped significantly, confirmed by visual inspection of the spa operators. The pool of the main spring almost emptied and the flow rate was significantly reduced, implying a profound change in the system. Similar water level drops occurred in the following months. Gas bubbles are likely to play a major role with respect to spatio-temporal variations in shallow fluid systems below Solfatara. Thus, additional to the field measurements we investigate potential bubble-related mechanisms capable to increase fluid pressure. The BubbleLab at GFZ has been setup. We are able to simulate earthquake ground motions with a shaking table, track the size and velocity of rising bubbles via a camera system, and quantify transients with a set of

  13. Analysis of reactivity and temperature transient experiments at the AVR high-temperature reactor

    SciTech Connect

    Scherer, W.; Gerwin, H.; Kindt, T.; Patscher, W.

    1987-09-01

    In the Arbeitsgemeinschaft Versuchsreaktor high-temperature reactor low-enriched fuel elements have been loaded for several years, replacing about half of the initial highly enriched uranium-thorium fuel. This changeover is accompanied by an elaborate experimental program wherein changes in the neutronic and thermohydraulics behavior of the system are monitored. Within this program reactor transients are induced by means of either circulator speed reduction or control rod movement. The resulting transients in neutron flux and temperatures are recorded and used as a basis for detailed theoretical analysis. Working groups at several institutions have carried out transient calculations using different dynamic codes. The results are presented and differences are discussed. In general, the experimental values were reproduced in a very satisfactory way.

  14. Analysis of transient flow and starting pressure gradient of power-law fluid in fractal porous media

    NASA Astrophysics Data System (ADS)

    Tan, Xiao-Hua; Li, Xiao-Ping; Zhang, Lie-Hui; Liu, Jian-Yi; Cai, Jianchao

    2015-09-01

    A transient flow model for power-law fluid in fractal porous media is derived by combining transient flow theory with the fractal properties of tortuous capillaries. Pressure changes of transient flow for power-law fluid in fractal porous media are related to pore fractal dimension, tortuosity fractal dimension and the power-law index. Additionally, the starting pressure gradient model of power-law fluid in fractal porous media is established. Good agreement between the predictions of the present model and that of the traditional empirical model is obtained, the sensitive parameters that influence the starting pressure gradient are specified and their effects on the starting pressure gradient are discussed.

  15. Development of single fluid volume element method for simulation of transient fluid flow in self-siphons

    NASA Astrophysics Data System (ADS)

    Viridi, S.; Novitrian, Nurhayati, Hidayat, W.; Latief, F. D. E.; Zen, F. P.

    2014-09-01

    A simple model for transient flow in a narrow pipe is presented in this work. The model is simply derived from Newton's second law of motion. As an example it is used to predict flow occurrence in two forms of self-siphon, which are inverted-U and M-like forms. Simulation for system consists only a vertical pipe is also presented since it is actually part of the both siphon systems. For the simple systems the model can have good predictions but for the complex system it can only have 89.6 % good prediction. Its simplicity can be used to illustrate how the interface between fluid and air, single fluid volume element (SFVE) moves along the siphon. The method itself is named as SFVE method.

  16. Temperature Measurement in Supersonic Flows by Predissociative Transient Thermal Gratings

    NASA Astrophysics Data System (ADS)

    Barker, Peter; Miles, Richard

    1998-11-01

    We present temporally resolved measurements of temperature in a range of supersonic flows by measuring the acoustic decay of laser created transient gratings. This is an extension of the LITA (Laser-Induced Thermal Acoustics) technique. A thermal density grating is created in the flow folloing absorption and thermalization of light from an interference pattern created by the crossed beams of a short-pulsed laser. Rapid thermalization occurs by collisions with energetic 0 photofragments following predissociation of O^2 in air by absorption of 193 nm light. The grating relaxes to local equilibrium by acoustic and diffusive decay. The acoustic decay launches two counter- propagating gratings traveling at the speed-of-sound. The interference of the stationary thermal grating with the two counter-propagating acoustic gratings creates a variation in grating modulation depth with time. The modulation frequency is proportional to the speed-of-sound and is used in our measurements to determine temperature. Bragg diffraction off the grating by a cw probe laser is observed as an oscillatory decay over hundreds of nanoseconds; the modulation frequency is extracted from this signal by Fourier analysis. We present single laser pulse measurements of temperature in a Mach 2.0 and 3.9 nozzle flows, and in weakly ionized flows for which this technique has been developed.

  17. Numerical Analysis of Transient Temperature Response of Soap Film

    NASA Astrophysics Data System (ADS)

    Tanaka, Seiichi; Tatesaku, Akihiro; Dantsuka, Yuki; Fujiwara, Seiji; Kunimine, Kanji

    2015-11-01

    Measurements of thermophysical properties of thin liquid films are important to understand interfacial phenomena due to film structures composed of amphiphilic molecules in soap film, phospholipid bilayer of biological cell and emulsion. A transient hot-wire technique for liquid films less than 1 \\upmu m thick such as soap film has been proposed to measure the thermal conductivity and diffusivity simultaneously. Two-dimensional heat conduction equations for a solid cylinder with a liquid film have been solved numerically. The temperature of a thin wire with liquid film increases steeply with its own heat generation. The feasibility of this technique is verified through numerical experiments for various thermal conductivities, diffusivities, and film thicknesses. Calculated results indicate that the increase in the volumetric average temperature of the thin wire sufficiently varies with the change of thermal conductivity and diffusivity of the soap film. Therefore, the temperature characteristics could be utilized to evaluate both the thermal conductivity and diffusivity using the Gauss-Newton method.

  18. Thermal fluids in low temperature systems. Part 2

    SciTech Connect

    Lynde, P.G.; Yonkers, E.D.

    1996-02-01

    This article focuses on the lifeblood of these systems, the thermal transfer fluid itself. Low-temperature heat-transfer fluids are used to condition engine fluids, test chambers, cooling fluids, or a combination of these in environmental test facilities. To meet the specific test criteria, these fluids may be required to maintain pumpability and function with thermal efficiency at temperatures as low as {minus}120 F. This article presents information related to heat-transfer fluids used in low-temperature cooling applications. Three general groups of fluids are discussed: water-based antifreezes (ethylene and propylene glycol solutions); chlorinated solvents (methylene chloride and trichloroethylene); organic and synthetic coolants (diethylbenzene, two forms of dimethylpolysiloxane, heavy naphtha hydrotreated, and citrus terpene).

  19. Code System to Calculate Transient 2-Dimensional 2-Fluid Flow Dynamics.

    Energy Science and Technology Software Center (ESTSC)

    1999-07-19

    Version 00 The transient dynamics of two-dimensional, two-phase flow with interfacial exchange are calculated at all flow speeds. Each phase is described in terms of its own density, velocity, and temperature. Separate sets of field equations govern the gas and liquid phase dynamics. The six field equations for the two phases couple through mass, momentum, and energy exchange.

  20. Transient temperature distributions in a cylinder heated by microwaves

    SciTech Connect

    Jackson, H.W.; Barmatz, M.; Wagner, P.

    1996-12-31

    Transient temperature distributions were calculated for a lossy dielectric cylinder coaxially aligned in a cylindrical microwave cavity excited in a single mode. Results were obtained for sample sizes that range from fibers to large cylinders. Realistic values for temperature dependent complex dielectric constants and thermophysical properties of the samples were used. Losses in cavity walls were taken into account as were realistic thermal emissivities at all surfaces. For a fine mesh of points in time, normal mode properties and microwave power absorption profiles were evaluated using analytic expressions. Those expressions correspond to exact solutions of Maxwell`s equations within the framework of a cylindrical shell model. Heating produced by the microwave absorption was included in self-consistent numerical solutions of thermal equations. In this model, both direct microwave heating and radiant heating of the sample (hybrid heating) were studied by including a lossy dielectric tube surrounding the sample. Calculated results are discussed within the context of two parametric studies. One is concerned with relative merits of microwave and hybrid heating of fibers, rods, and larger cylinders. The other is concerned with thermal runaway.

  1. Validation of a fluid-structure interaction numerical model for predicting flow transients in arteries.

    PubMed

    Kanyanta, V; Ivankovic, A; Karac, A

    2009-08-01

    Fluid-structure interaction (FSI) numerical models are now widely used in predicting blood flow transients. This is because of the importance of the interaction between the flowing blood and the deforming arterial wall to blood flow behaviour. Unfortunately, most of these FSI models lack rigorous validation and, thus, cannot guarantee the accuracy of their predictions. This paper presents the comprehensive validation of a two-way coupled FSI numerical model, developed to predict flow transients in compliant conduits such as arteries. The model is validated using analytical solutions and experiments conducted on polyurethane mock artery. Flow parameters such as pressure and axial stress (and precursor) wave speeds, wall deformations and oscillating frequency, fluid velocity and Poisson coupling effects, were used as the basis of this validation. Results show very good comparison between numerical predictions, analytical solutions and experimental data. The agreement between the three approaches is generally over 95%. The model also shows accurate prediction of Poisson coupling effects in unsteady flows through flexible pipes, which up to this stage have only being predicted analytically. Therefore, this numerical model can accurately predict flow transients in compliant vessels such as arteries. PMID:19482285

  2. Transient response of an electrorheological fluid under square-wave electric field excitation.

    PubMed

    Tian, Yu; Li, Cuihong; Zhang, Minliang; Meng, Yonggang; Wen, Shizhu

    2005-08-01

    The transient process of an electrorheological (ER) fluid based on zeolite and silicone oil sheared between two parallel plates to which a square-wave electric field is applied has been experimentally studied. The transient shear stress response to the strain or time is tested. The characteristic constants of time under different applied electric fields and shear rates have been determined. The response time is found to be proportional to shear rate with an exponent of about -0.75 in the tested shear rate range, which agrees with the theoretical predictions made by others. But it only shows a small dependence on the strength of the applied electric field. The results show that the transient process of ER fluids is related to the structure formation in the shearing. When the required shear strain is reached, the shear stress rises to a stable value under constant electric field. Although the electric field strength greatly affects the yield strength, it shows little effect on the stress response time. Also, experiments showed the electric field-induced shear stress decreased with an increase of shear rate. PMID:15927589

  3. Steady and transient fluid shear stress stimulate NO release in osteoblasts through distinct biochemical pathways

    NASA Technical Reports Server (NTRS)

    McAllister, T. N.; Frangos, J. A.

    1999-01-01

    Fluid flow has been shown to be a potent stimulus in osteoblasts and osteocytes and may therefore play an important role in load-induced bone remodeling. The objective of this study was to investigate the characteristics of flow-activated pathways. Previously we reported that fluid flow stimulates rapid and continuous release of nitric oxide (NO) in primary rat calvarial osteoblasts. Here we demonstrate that flow-induced NO release is mediated by shear stress and that this response is distinctly biphasic. Transients in shear stress associated with the onset of flow stimulated a burst in NO production (8.2 nmol/mg of protein/h), while steady flow stimulated sustained NO production (2.2 nmol/mg of protein/h). Both G-protein inhibition and calcium chelation abolished the burst phase but had no effect on sustained production. Activation of G-proteins stimulated dose-dependent NO release in static cultures of both calvarial osteoblasts and UMR-106 osteoblast-like cells. Pertussis toxin had no effect on NO release. Calcium ionophore stimulated low levels of NO production within 15 minutes but had no effect on sustained production. Taken together, these data suggest that fluid shear stress stimulates NO release by two distinct pathways: a G-protein and calcium-dependent phase sensitive to flow transients, and a G-protein and calcium-independent pathway stimulated by sustained flow.

  4. Fracturing fluid high-temperature breaker for improving well performance

    SciTech Connect

    McConnell, B.

    1994-05-01

    Oxidative breakers are currently being used in fracturing treatments to reduce polymeric gel damage in high-temperature reservoirs. Dissolved high-temperature oxidative breakers are very reactive at high temperatures (275 to 350 F), typically requiring less than 0.25 lbm/1,000 gal of fluid. Recent introduction of a new nonpersulfate oxidative high-temperature encapsulated breaker (HTEB) provides controlled degradation of the fracturing fluid polymers. Laboratory tests show viscosity reduction and delayed release of active oxidizer breaker. HTEB conductivity data show a two-fold increase in retained permeability at 300 F in a borate-crosslinked fluid system.

  5. Draft tube pressure pulsation predictions in Francis turbines with transient Computational Fluid Dynamics methodology

    NASA Astrophysics Data System (ADS)

    Melot, M.; Nennemann, B.; Désy, N.

    2014-03-01

    An automatic Computational Fluid Dynamics (CFD) procedure that aims at predicting Draft Tube Pressure Pulsations (DTPP) at part load is presented. After a brief review of the physics involved, a description of the transient numerical setup is given. Next, the paper describes a post processing technique, namely the separation of pressure signals into synchronous, asynchronous and random pulsations. Combining the CFD calculation with the post-processing technique allows the quantification of the potential excitation of the mechanical system during the design phase. Consequently it provides the hydraulic designer with a tool to specifically target DTPP and thus helps in the development of more robust designs for part load operation of turbines.

  6. TEMPEST: A computer code for three-dimensional analysis of transient fluid dynamics

    SciTech Connect

    Fort, J.A.

    1995-06-01

    TEMPEST (Transient Energy Momentum and Pressure Equations Solutions in Three dimensions) is a powerful tool for solving engineering problems in nuclear energy, waste processing, chemical processing, and environmental restoration because it analyzes and illustrates 3-D time-dependent computational fluid dynamics and heat transfer analysis. It is a family of codes with two primary versions, a N- Version (available to public) and a T-Version (not currently available to public). This handout discusses its capabilities, applications, numerical algorithms, development status, and availability and assistance.

  7. Transient shutdown analysis of low-temperature thermal diodes

    NASA Technical Reports Server (NTRS)

    Williams, R. J.

    1979-01-01

    The various thermal diodes available for use in cryogenic systems are described. Two diode types, liquid-trap and liquid-blockage diodes, were considered to be the most attractive, and thermal models were constructed to predict their behavior in the reverse mode. The diodes, which are of similar size and throughput, were also examined experimentally in a parallel test setup under nominally identical conditions. Their characteristics were ascertained in terms of forward-mode and reverse-mode conductances, shutdown times and energies, and recovery to forward-mode operation with ethane as the working fluid in the temperature range 170 K to 220 K. Results show that the liquid-blockage diode is the quicker of the two diodes to shut down from the forward mode (8 min as opposed to 10 min). However, the liquid-blockage diode has a larger reverse-mode conductance which results in a greater overall evaporator temperature rise. The importance of the relative size and heat inputs to the condenser/reservoir configuration of the liquid-blockage diode and the evaporator trap configuration for the liquid-trap diode are demonstrated. Also included are data which show the susceptibility of the diodes to recovery to forward-mode operation. Guidelines for the choice of a particular diode for an actual application are given.

  8. Transient electrokinetic response of finely layered, fluid-filled porous media

    NASA Astrophysics Data System (ADS)

    Dietrich, M.; Delprat-Jannaud, F.; Garambois, S.

    2012-04-01

    Transient electrokinetic coupling phenomena created at the microscopic scale by the passage of seismic waves through fluid-saturated porous media generate conversions between seismic and electromagnetic (EM) energy which can be observed at the macroscopic scale. Far from being a mere scientific curiosity, transient seismoelectric or electroseismic phenomena are especially appealing to oil and gas exploration and hydrogeology as they open up the (fairly unique) possibility to characterize fluid-bearing geological formations with the resolution of seismic methods. Indeed, electrokinetic effects are likely to reconcile the sensitivity of electromagnetic exploration methods to fluids with the high resolving power of seismic prospecting techniques for structural imaging, thus naturally bridging the gap between these two important geophysical investigation means. Accounting for the electromagnetic dimension of the seismic wave propagation, or conversely, accounting for the seismic dimension of electromagnetic wave propagation gives new insights into the microstructure and physico-chemistry of fluid-filled porous or fractured media. We present full-waveform simulations of the coupled seismoelectromagnetic wave propagation in fluid-saturated, finely stratified porous media of interest to oil and gas exploration. Our simulation code uses the macroscopic governing equations derived by Pride [1994], which couple Biot's theory and Maxwell equations via flux/force transport equations. The synthetic seismoelectrograms and seismomagnetrograms are computed by extending the generalized reflection and transmission matrix method and by using a discrete wave number integration of the global reflectivity obtained in the frequency wave number domain. The theoretical signals clearly display the coseismic electric and magnetic fields travelling with the seismic disturbances as well as the seismic-to-electromagnetic conversions taking place at contrasts in solid and fluid properties. Our

  9. WHTSubmersible: a simulator for estimating transient circulation temperature in offshore wells with the semi-submersible platform

    NASA Astrophysics Data System (ADS)

    Song, Xun-cheng; Liu, Yong-wang; Guan, Zhi-chuan

    2015-10-01

    Offshore wellbore temperature field is significant to drilling fluids program, equipment selection, evaluations on potential risks caused by casing thermal stress, etc. This paper mainly describes the theoretical basis, module structure and field verification of the simulator WHTSubmersible. This computer program is a useful tool for estimating transient temperature distribution of circulating drilling fluid on semi-submersible platform. WHTSubmersible is based on a mathematical model which is developed to consider radial and axial two-dimensional heat exchange of the inner drill pipe, the annulus, the drill pipe wall, the sea water and the formation in the process of drilling fluid circulation. The solution of the discrete equations is based on finite volume method with an implicit scheme. This scheme serves to demonstrate the numerical solution procedure. Besides, the simulator also considers the heating generated by drilling fluid circulation friction, drill bit penetrating rocks, friction between the drill column and the borehole wall, and the temperature effect on thermal physical properties and rheology of the drilling fluid. These measures ensure more accurate results. The simulator has been programmed as a dynamic link library using Visual C++, the routine interface is simple, which can be connected with other computer programs conveniently. The simulator is validated with an actual well temperature filed developed on a semi-submersible platform in South China, and the error is less than 5 %.

  10. Thermo-Physical Properties of Intermediate Temperature Heat Pipe Fluids

    NASA Technical Reports Server (NTRS)

    Beach, Duane E. (Technical Monitor); Devarakonda, Angirasa; Anderson, William G.

    2005-01-01

    Heat pipes are among the most promising technologies for space radiator systems. The paper reports further evaluation of potential heat pipe fluids in the intermediate temperature range of 400 to 700 K in continuation of two recent reports. More thermo-physical property data are examined. Organic, inorganic, and elemental substances are considered. The evaluation of surface tension and other fluid properties are examined. Halides are evaluated as potential heat pipe fluids. Reliable data are not available for all fluids and further database development is necessary. Many of the fluids considered are promising candidates as heat pipe fluids. Water is promising as a heat pipe fluid up to 500 to 550 K. Life test data for thermo-chemical compatibility are almost non-existent.

  11. Volume and density changes of biological fluids with temperature

    NASA Technical Reports Server (NTRS)

    Hinghofer-Szalkay, H.

    1985-01-01

    The thermal expansion of human blood, plasma, ultrafiltrate, and erythrocycte concentration at temperatures in the range of 4-48 C is studied. The mechanical oscillator technique which has an accuracy of 1 x 10 to the -5 th g/ml is utilized to measure fluid density. The relationship between thermal expansion, density, and temperature is analyzed. The study reveals that: (1) thermal expansion increases with increasing temperature; (2) the magnitude of the increase declines with increasing temperature; (3) thermal expansion increases with density at temperatures below 40 C; and (4) the thermal expansion of intracellular fluid is greater than that of extracellular fluid in the temperature range of 4-10 C, but it is equal at temperatures greater than or equal to 40 C.

  12. 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).

  13. [Testing Research of Transient Temperature Distribution for the Barrel Surface by Speckle Pattern Interferometry].

    PubMed

    Lang, Wen-jie; Chen, Guo-guang; Tian, Xiao-li; Xin, Chang-fan

    2016-02-01

    There are some problems in the traditional transient temperature test equipment. The thermal inertia is great, and can only be a single point of detection. To be able to achieve real-time monitoring for transient temperature distribution change of the gun body surface, the test system for transient temperature distribution was designed based on Speckle Pattern Interferometry (SPI) and spectroscopy. In the system, transient temperature change of the barrel led to slight deformation, and it was converted into speckle interference fringes by SPI technology. Spectral distribution function was obtained by the interference fringes by the Fourier transform, so the information of interference fringe deformation was incorporated into the frequency domain. The data of temperature distribution can be inverted on any sampling time by spectral distribution function. In experiments, the ZX-FB1 fiber optic thermometer was used to test transient temperature on a single point as the standard value. The center wavelength of the laser was 555 nm, and the speckle pattern interference fringes were collected by area array CCD. Image Recognition-Speckle Pattern Interferometry (IR-SPI) and Fourier Transform-Speckle Pattern Interferometry (FT-SPI) were used in experiments, the calculation of transient temperature was completed through two methods. Experimental results are that both methods can achieve transient temperature detection. But the FT-SPI is higher in terms of accuracy, and it can effectively overcome the gross error caused by the surface defects, paint wear and other similar problems. PMID:27209730

  14. Effect of temperature on rotational viscosity in magnetic nano fluids.

    PubMed

    Patel, R

    2012-10-01

    Flow behavior of magnetic nano fluids with simultaneous effect of magnetic field and temperature is important for its application for cooling devices such as transformer, loud speakers, electronic cooling and for its efficiency in targeted drug delivery and hyperthermia treatment. Using a specially designed horizontal capillary viscometer, temperature-sensitive and non-temperature-sensitive magnetic nano fluids are studied. In both these case the temperature-dependent rotational viscosity decreases, but follows a quite different mechanism. For temperature-sensitive magnetic nano fluids, the reduction in rotational viscosity is due to the temperature dependence of magnetization. Curie temperature ((T)(c)) and pyromagnetic coefficient are extracted from the study. A fluid with low T(c) and high pyromagnetic coefficient is useful for thermo-sensitive cooling devices and magnetic hyperthermia. For non-temperature-sensitive magnetic nano fluids, reduction in rotational viscosity is due to removal of physisorbed secondary surfactant on the particle because of thermal and frictional effects. This can be a good analogy for removal of drug from the magnetic particles in the case of targeted drug delivery. PMID:23096152

  15. Temperature dependence of fluid transport in nanopores

    NASA Astrophysics Data System (ADS)

    Xu, Baoxing; Wang, Binglei; Park, Taehyo; Qiao, Yu; Zhou, Qulan; Chen, Xi

    2012-05-01

    Understanding the temperature-dependent nanofluidic transport behavior is critical for developing thermomechanical nanodevices. By using non-equilibrium molecular dynamics simulations, the thermally responsive transport resistance of liquids in model carbon nanotubes is explored as a function of the nanopore size, the transport rate, and the liquid properties. Both the effective shear stress and the nominal viscosity decrease with the increase of temperature, and the temperature effect is coupled with other non-thermal factors. The molecular-level mechanisms are revealed through the study of the radial density profile and hydrogen bonding of confined liquid molecules. The findings are verified qualitatively with an experiment on nanoporous carbon.

  16. Streptococcus mutans biofilm transient viscoelastic fluid behaviour during high-velocity microsprays.

    PubMed

    Fabbri, S; Johnston, D A; Rmaile, A; Gottenbos, B; De Jager, M; Aspiras, M; Starke, E M; Ward, M T; Stoodley, P

    2016-06-01

    Using high-speed imaging we assessed Streptococcus mutans biofilm-fluid interactions during exposure to a 60-ms microspray burst with a maximum exit velocity of 51m/s. S. mutans UA159 biofilms were grown for 72h on 10mm-length glass slides pre-conditioned with porcine gastric mucin. Biofilm stiffness was measured by performing uniaxial-compression tests. We developed an in-vitro interproximal model which allowed the parallel insertion of two biofilm-colonized slides separated by a distance of 1mm and enabled high-speed imaging of the removal process at the surface. S. mutans biofilms were exposed to either a water microspray or an air-only microburst. High-speed videos provided further insight into the mechanical behaviour of biofilms as complex liquids and into high-shear fluid-biofilm interaction. We documented biofilms extremely transient fluid behaviour when exposed to the high-velocity microsprays. The presence of time-dependent recoil and residual deformation confirmed the pivotal role of viscoelasticity in biofilm removal. The air-only microburst was effective enough to remove some of the biofilm but created a smaller clearance zone underlying the importance of water and the air-water interface of drops moving over the solid surface in the removal process. Confocal and COMSTAT analysis showed the high-velocity water microspray caused up to a 99.9% reduction in biofilm thickness, biomass and area coverage, within the impact area. PMID:26771168

  17. Fluids at high dynamic pressures and temperatures

    SciTech Connect

    Nellis, W.J.; Hamilton, D.C.; Trainor, R.J.; Radousky, H.B.; Mitchell, A.C.; Holmes, N.C.

    1985-06-01

    Electrical conductivity data for shocked liquid nitrogen, Hugoniot data for liquid air, shock temperatures for liquid ammonia, and double-shock equation-of-state data for Al are discussed. 15 refs., 2 figs.

  18. Temperature dependence of particle-particle interactions in electrorheological fluids

    NASA Astrophysics Data System (ADS)

    Gonon, P.; Foulc, J.-N.

    2000-04-01

    We report on the temperature dependence of particle-particle interactions in electrorheological (ER) fluids for the temperature range 20-100 °C. The attraction force between polyamide spheres immersed in silicone oil is measured as a function of temperature. The force-temperature characteristic shows a broad maximum around 40 °C, corresponding to an increase of about 30% compared to the force measured at room temperature. In view of these results we proposed that the temperature dependence of the shear stress in ER fluids is directly related to the variation of the local particle-particle attraction forces. Data are discussed in light of models which were proposed in the literature to describe particle-particle interactions. At high electric fields "conduction models" could explain the observed temperature dependence through the variations of the oil breakdown field with temperature. However, limitations of such models are also clearly evidenced by data obtained at low electric fields.

  19. Hydrostatic fluid bearing gyro. [temperature control

    NASA Technical Reports Server (NTRS)

    Brello, E. Y.

    1975-01-01

    The design, fabrication, and testing are described of a thermal control assembly capable of precisely controlling the LDG-540 Gyro case temperature at 50 C over an ambient environment range of 23 C and atmosphere pressure to 5 C and a vacuum of 0.00001 torr. The thermal control assembly is a hermetically sealed enclosure about the LDG-540 Gyro with envelope dimensions not to exceed those of the Saturn K8-AB5 Gyro. The heaters are capable of delivery 30 watts at 28 V.D.C. and have dual temperature sensors rated at 750 ohms at 50 C. All six (6) LGD-540 Gyros will be equipped with a fine control heater and a resistance thermometer to monitor the gyro cast temperature. All six gyros will be interchangeable in the thermal control assembly by means of simply assembly techniques.

  20. Adiabatic Compression of Oxygen: Real Fluid Temperatures

    NASA Technical Reports Server (NTRS)

    Barragan, Michelle; Wilson, D. Bruce; Stoltzfus, Joel M.

    2000-01-01

    The adiabatic compression of oxygen has been identified as an ignition source for systems operating in enriched oxygen atmospheres. Current practice is to evaluate the temperature rise on compression by treating oxygen as an ideal gas with constant heat capacity. This paper establishes the appropriate thermodynamic analysis for the common occurrence of adiabatic compression of oxygen and in the process defines a satisfactory equation of state (EOS) for oxygen. It uses that EOS to model adiabatic compression as isentropic compression and calculates final temperatures for this system using current approaches for comparison.

  1. Fluid-temperature logs for selected wells in eastern Washington

    SciTech Connect

    Stoffel, K.L.; Widness, S.

    1983-12-01

    This Open-File Report consists of fluid temperature logs compiled during studies of the geohydrology and low temperature geothermal resources of eastern Washington. The fluid temperature logs are divided into two groups. Part A consists of wells which are concentrated in the Moses Lake-Ritzville-Connell area. Full geophysical log suites for many of these wells are presented in Stoffel and Widness (1983) and discussed in Widness (1983, 1984). Part B consists of wells outside of the Moses Lake-Ritzville-Connell study area.

  2. Transient elasticity and the rheology of polymeric fluids with large amplitude deformations.

    PubMed

    Müller, Oliver; Liu, Mario; Pleiner, Harald; Brand, Helmut R

    2016-02-01

    Transient elasticity is a systematic generalization of viscoelasticity. Its purpose is to give a coherent description of non-Newtonian effects displayed by soft-matter systems, especially polymer melts and solutions. Using the concept of transient elasticity we describe here a hydrodynamic model for polymeric fluids, which is applicable for large amplitude deformations. We present an energy density with only two independent parameters, which is compatible with all thermodynamic requirements and which reduces for small deformations to models studied previously. The expression discussed is simple enough to allow full analytic treatment and shows semiquantitative agreement with experimental data. This model is used to capture many of the interesting effects thought to be characteristic of polymer rheology for large deformations including viscosity overshoot near the onset of shear flow, the onset of elongational flows in situations for which there is no stationary solution as well as shear thinning and normal stress differences for a large range of shear rates. In addition, we analyze how well our model accounts for empirical relations including the Cox-Merz rule, the Yamamoto relation, and Gleißle's mirror relations. PMID:26986420

  3. Transient elasticity and the rheology of polymeric fluids with large amplitude deformations

    NASA Astrophysics Data System (ADS)

    Müller, Oliver; Liu, Mario; Pleiner, Harald; Brand, Helmut R.

    2016-02-01

    Transient elasticity is a systematic generalization of viscoelasticity. Its purpose is to give a coherent description of non-Newtonian effects displayed by soft-matter systems, especially polymer melts and solutions. Using the concept of transient elasticity we describe here a hydrodynamic model for polymeric fluids, which is applicable for large amplitude deformations. We present an energy density with only two independent parameters, which is compatible with all thermodynamic requirements and which reduces for small deformations to models studied previously. The expression discussed is simple enough to allow full analytic treatment and shows semiquantitative agreement with experimental data. This model is used to capture many of the interesting effects thought to be characteristic of polymer rheology for large deformations including viscosity overshoot near the onset of shear flow, the onset of elongational flows in situations for which there is no stationary solution as well as shear thinning and normal stress differences for a large range of shear rates. In addition, we analyze how well our model accounts for empirical relations including the Cox-Merz rule, the Yamamoto relation, and Gleißle's mirror relations.

  4. Nonvolcanic Tremors and Intraslab Fluid Migration in Guerrero, Mexico, During Slow Slip Transients

    NASA Astrophysics Data System (ADS)

    Cruz-Atienza, V. M.; Husker, A. L.; Villafuerte, C. D.; Caballero, E.; Legrand, D.; Kostoglodov, V.

    2014-12-01

    migration speeds. We conclude that fluid diffusive transport is not responsible of the NVT and LFE migration during the SSEs but instead that slip transients act as a long-term pumping process decreasing the effective pressure where the seismicity takes place as a consequence of small stress perturbations associated to the propagation of the aseismic slip.

  5. Extended Vofire algorithm for fast transient fluid-structure dynamics with liquid-gas flows and interfaces

    NASA Astrophysics Data System (ADS)

    Faucher, Vincent; Kokh, Samuel

    2013-05-01

    The present paper is dedicated to the simulation of liquid-gas flows with interfaces in the framework of fast transient fluid-structure dynamics. The two-fluid interface is modelled as a discontinuity surface in the fluid property. We use an anti-dissipative Finite-Volume discretization strategy for unstructured meshes in order to capture the position of the interface within a thin diffused volume. This allows to control the numerical diffusion of the artificial mixing between components and provide an accurate capture of complex interface motions. This scheme is an extension of the Vofire numerical solver. We propose specific developments in order to handle flows that involved high density ratio between liquid and gas. The resulting scheme capabilities are validated on basic examples and also tested against large scale fluid-structure test derived from the MARA 10 experiment. All simulations are performed using EUROPLEXUS fast transient dynamics software.

  6. Bond homolysis in high-temperature fluids

    SciTech Connect

    Stein, S.E.; Robaugh, D.A.; Alfieri, A.D.; Miller, R.E.

    1982-12-01

    Rate constants for the homolysis of 1,2-diphenylethane have been determined in tetralin, in dodecahydrotriphenylene, and in the gas phase at temperatures above 350/sup 0/C. The least-squares-derived Arrhenius expression for this reaction in the gas phase is k/sub 1//s/sup -1/ = 10/sup (15.25+-0.15)-(62.31+-0.50)/theta (theta = 0.004576T/K) and is consistent with available thermokinetic data. In liquid tetralin up to its critical temperature and in liquid dodecahydrotriphenylene Arrhenius parameters for this reaction were found to be distinctly higher than gas-phase values, and rate constants to be somewhat lower. These differences between gas- and liquid-phase kinetics are attributed to recombination of nascent free radicals in solution (the cage effect), the probability of which decreases with decreasing viscosity.

  7. Convective heat transfer to low-temperature fluids

    NASA Technical Reports Server (NTRS)

    Graham, R. W.; Hendricks, R. C.; Simoneau, R. J.

    1974-01-01

    Research into forced and natural convection processes in low-temperature (cryogenic) fluids is reviewed with primary emphasis on forced convection. Boundaries of the near-critical region are defined, fluid properties near the critical state are discussed, and heat-transfer processes around the critical point are described. The thermodynamics of the critical point is analyzed together with transport properties of a near-critical fluid, and the quantum states of low-temperature molecular hydrogen (para and ortho) are discussed. Experimental work on heat transfer in free, natural, and forced convection systems is briefly summarized. Graham's (1969) penetration model for near-critical fluids is outlined, near-critical heat transfer is discussed in relation to conventional geometric effects, and the effects of curvature on the properties of near-critical hydrogen are noted. Theoretical considerations in free and forced convection are examined.

  8. On the Ginzburg temperature of ionic and dipolar fluids

    NASA Astrophysics Data System (ADS)

    Weiss, V. C.; Schröer, W.

    1997-02-01

    Critical fluctuations in fluids are investigated within the framework of the generalized van der Waals theory. The square-gradient term—added to the Landau expansion of the Helmholtz free energy density—is obtained following a procedure similar to that originally proposed by van der Waals in the theory of surface tension, however replacing the Heaviside step function originally used by an approximative pair distribution function. Representative for ionic fluids we choose the restricted primitive model (RPM) and treat it within the Debye-Hückel theory, thus neglecting effects of ion pairing. The other approximative extreme—complete ion pairing resulting in a fluid of hard dipolar dumbbells—is mimicked by a fluid composed of dipolar hard spheres (DHS). For this case we use the Onsager reaction field and the second pressure virial coefficient. We calculate the amplitudes of the correlation length and the Ginzburg temperatures, and find (in reduced quantities) ξ0*=3.50 and ΔTGi*=0.0087 for the ionic system, and ξ0*=0.82 and ΔTGi*=1.63 for the dipolar fluid. For calibration we compute the same quantities for simple neutral fluids and obtain ξ0*=0.50 and ΔTGi*=2.89 for a Sutherland fluid (hard core term plus attractive r-6-potential) and ξ0*=0.43 and ΔTGi*=8.50 for a square-well fluid. The result of a smaller Ginzburg temperature for the ionic fluid than for nonionic fluids in a treatment that neglects ion pairing is clearly at variance with the results of other groups. The correlation length in the low-density limit obtained from our approach has the same functional dependencies as the Lee-Fisher expression, but differs by a numerical factor of 5.7.

  9. Vibrational spectroscopy in high temperature dense fluids

    SciTech Connect

    Moore, D.S.; Schmidt, S.C.

    1992-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) in conjunction with a two-stage light-gas gun has been used to obtain vibrational spectra of shock-compressed liquid N{sub 2}, O{sub 2}, CO, and their mixtures, as well as liquid N{sub 2}O. The experimental spectra are compared to spectra calculated using a semiclassical model for CARS intensities to obtain vibrational frequencies, peak Raman susceptibilities, and linewidths. The derived spectroscopic parameters suggest thermal equilibrium of the vibrational populations is established in less than a few nanoseconds after shock passage. Vibrational temperatures obtained are compared to those derived from equation-of-state calculations. The variation of the vibrational frequency shift at pressure with species concentration in mixtures is investigated.

  10. Effect of Non-Uniform Inlet Temperature on Flow Stagnation in a Pumped Fluid Tube Radiator

    NASA Astrophysics Data System (ADS)

    Reavis, Gretchen

    2008-01-01

    The effect of a non-uniform inlet temperature on the panel fluid tube flow stagnation point is examined using a spacecraft radiator panel model with 20 fluid tubes constructed in Thermal Desktop®. Fluid temperature variations due to panel edge effect and localized hot and cold spots in the flow path were simulated by varying the fluid inlet temperature on one or more tubes. Results show that a large fluid inlet temperature difference between tubes can decrease the fluid system stability and increase the possibility of fluid stagnation with the coldest fluid tube initiating stagnation. Conversely, a small fluid inlet temperature difference between tubes can, in some cases, increase the fluid system stability and decrease the possibility of fluid stagnation. A uniform fluid inlet temperature provides for a near optimization of the stagnation point as compared to fluid temperature gradients across the panel.

  11. Controllable Fluids:. the Temperature Dependence of Post-Yield Properties

    NASA Astrophysics Data System (ADS)

    Weiss, Keith D.; Duclos, Theodore G.

    This paper represents the first detailed description of the affect of temperature on the properties exhibited by state-of-the-art electrorheological (ER) and magnetorheological (MR) fluids. In particular, shear stress versus shear strain rate curves, dynamic and static yield stress values, zero-field viscosity data, and current density measurements are discussed. Specific comments concerning the stability of both mechanical and electrical properties over broad temperature ranges are provided. Finally, insight into the advantages associated with using electrorheological and magnetorheological fluids in a controllable device is provided.

  12. Numerical simulation on influence of bonding temperature in transient liquid phase bonding

    NASA Astrophysics Data System (ADS)

    Hynes, N. Rajesh Jesudoss; Raja, M. Karthick

    2016-05-01

    In this article, numerical simulation of transient liquid phase bonding of ceramic/metal joint has been carried out by using Finite Element Analysis (FEA) software. To increase the wettability, aluminium sheet was used as an interlayer. Hence, numerical simulation of TLP bonding process is done by varying the bonding temperature. Transient thermal analysis had been carried out for each cases and temperature distribution was predicted by the developed numerical model. From the simulation studies, it is found that the decrease in bonding temperature enhances favourable temperature distribution and eventually improves the joint efficiency of graphite/copper joints.

  13. Measurements of seismic attenuation and transient fluid pressure in partially saturated Berea sandstone: evidence of fluid flow on the mesoscopic scale

    NASA Astrophysics Data System (ADS)

    Tisato, Nicola; Quintal, Beatriz

    2013-10-01

    A novel laboratory technique is proposed to investigate wave-induced fluid flow on the mesoscopic scale as a mechanism for seismic attenuation in partially saturated rocks. This technique combines measurements of seismic attenuation in the frequency range from 1 to 100 Hz with measurements of transient fluid pressure as a response of a step stress applied on top of the sample. We used a Berea sandstone sample partially saturated with water. The laboratory results suggest that wave-induced fluid flow on the mesoscopic scale is dominant in partially saturated samples. A 3-D numerical model representing the sample was used to verify the experimental results. Biot's equations of consolidation were solved with the finite-element method. Wave-induced fluid flow on the mesoscopic scale was the only attenuation mechanism accounted for in the numerical solution. The numerically calculated transient fluid pressure reproduced the laboratory data. Moreover, the numerically calculated attenuation, superposed to the frequency-independent matrix anelasticity, reproduced the attenuation measured in the laboratory in the partially saturated sample. This experimental-numerical fit demonstrates that wave-induced fluid flow on the mesoscopic scale and matrix anelasticity are the dominant mechanisms for seismic attenuation in partially saturated Berea sandstone.

  14. Modeling and analysis of transient vehicle underhood thermo- hydrodynamic events using computational fluid dynamics and high performance computing.

    SciTech Connect

    Tentner, A.; Froehle, P.; Wang, C.; Nuclear Engineering Division

    2004-01-01

    This work has explored the preliminary design of a Computational Fluid Dynamics (CFD) tool for the analysis of transient vehicle underhood thermo-hydrodynamic events using high performance computing platforms. The goal of this tool will be to extend the capabilities of an existing established CFD code, STAR-CD, allowing the car manufacturers to analyze the impact of transient operational events on the underhood thermal management by exploiting the computational efficiency of modern high performance computing systems. In particular, the project has focused on the CFD modeling of the radiator behavior during a specified transient. The 3-D radiator calculations were performed using STAR-CD, which can perform both steady-state and transient calculations, on the cluster computer available at ANL in the Nuclear Engineering Division. Specified transient boundary conditions, based on experimental data provided by Adapco and DaimlerChrysler were used. The possibility of using STAR-CD in a transient mode for the entire period of time analyzed has been compared with other strategies which involve the use of STAR-CD in a steady-state mode at specified time intervals, while transient heat transfer calculations would be performed for the rest of the time. The results of these calculations have been compared with the experimental data provided by Adapco/DaimlerChrysler and recommendations for future development of an optimal strategy for the CFD modeling of transient thermo-hydrodynamic events have been made. The results of this work open the way for the development of a CFD tool for the transient analysis of underhood thermo-hydrodynamic events, which will allow the integrated transient thermal analysis of the entire cooling system, including both the engine block and the radiator, on high performance computing systems.

  15. Modeling and analysis of transient vehicle underhood thermo - hydrodynamic events using computational fluid dynamics and high performance computing.

    SciTech Connect

    Froehle, P.; Tentner, A.; Wang, C.

    2003-09-05

    This work has explored the preliminary design of a Computational Fluid Dynamics (CFD) tool for the analysis of transient vehicle underhood thermo-hydrodynamic events using high performance computing platforms. The goal of this tool will be to extend the capabilities of an existing established CFD code, STAR-CD, allowing the car manufacturers to analyze the impact of transient operational events on the underhood thermal management by exploiting the computational efficiency of modern high performance computing systems. In particular, the project has focused on the CFD modeling of the radiator behavior during a specified transient. The 3-D radiator calculations were performed using STAR-CD, which can perform both steady-state and transient calculations, on the cluster computer available at ANL in the Nuclear Engineering Division. Specified transient boundary conditions, based on experimental data provided by Adapco and DaimlerChrysler were used. The possibility of using STAR-CD in a transient mode for the entire period of time analyzed has been compared with other strategies which involve the use of STAR-CD in a steady-state mode at specified time intervals, while transient heat transfer calculations would be performed for the rest of the time. The results of these calculations have been compared with the experimental data provided by Adapco/DaimlerChrysler and recommendations for future development of an optimal strategy for the CFD modeling of transient thermo-hydrodynamic events have been made. The results of this work open the way for the development of a CFD tool for the transient analysis of underhood thermo-hydrodynamic events, which will allow the integrated transient thermal analysis of the entire cooling system, including both the engine block and the radiator, on high performance computing systems.

  16. Experimental transient turbine blade temperatures in a research engine for gas stream temperatures cycling between 1067 and 1567 k

    NASA Technical Reports Server (NTRS)

    Gauntner, D. J.; Yeh, F. C.

    1975-01-01

    Experimental transient turbine blade temperatures were obtained from tests conducted on air-cooled blades in a research turbojet engine, cycling between cruise and idle conditions. Transient data were recorded by a high speed data acquisition system. Temperatures at the same phase of each transient cycle were repeatable between cycles to within 3.9 K (7 F). Turbine inlet pressures were repeatable between cycles to within 0.32 N/sq cm (0.47 psia). The tests were conducted at a gas stream temperature of 1567 K (2360 F) at cruise, and 1067 K (1460 F) at idle conditions. The corresponding gas stream pressures were about 26.2 and 22.4 N/sq cm (38 and 32.5 psia) respectively. The nominal coolant inlet temperature was about 811 K (1000 F).

  17. Measuring transient high temperature thermal phenomena in hostile environment

    SciTech Connect

    Brenden, B.B.; Hartman, J.S.; Reich, F.R.

    1980-01-01

    The design of equipment for measuring temperature and strain in a rapidly heated and pressurized cylinder of stainless steel is discussed. Simultaneous cinematography of the full circumference of the cylinder without interference with temperature and strain measurements is also illustrated. The integrated system uses a reflective chamber for the sample and requires careful consideration of the spectral energy distribution utilized by each instrument.

  18. 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.

  19. 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.

  20. Transient solid-fluid interactions in rat brain tissue under combined translational shear and fixed compression.

    PubMed

    Haslach, Henry W; Leahy, Lauren N; Hsieh, Adam H

    2015-08-01

    An external mechanical insult to the brain may create internal deformation waves, which have shear and longitudinal components that induce combined shear and compression of the brain tissue. To isolate such interactions and to investigate the role of the extracellular fluid (ECF) in the transient mechanical response, translational shear stretch up to 1.25 under either 0 or 33% fixed normal compression is applied without preconditioning to heterogeneous sagittal slices which are nearly the full length of the rat brain cerebrum. The normal stress contribution is estimated by separate unconfined compression stress-stretch curves at 0.0667/s and 1/s engineering strain rates to 33% strain. Unconfined compression deformation causes lateral dimension expansion less than that predicted for an incompressible material under large deformation and often a visible loss of internal fluid from the specimen so that the bulk brain tissue is not incompressible in vitro, as sometimes assumed for mathematical modeling. The response to both slow 0.001/s and moderate 1/s shear translational stretch rates is deformation rate dependent and hardening under no compression but under 33% compression is nearly linear perhaps because of increased solid-solid friction. Both shear and normal stress relaxation are faster after the fast rate deformation possibly because higher deformation rates produce higher ECF hydrostatic pressure that primarily drives stress relaxation. The experimental results on ECF behavior guide the form of our nonlinear viscoelastic mathematical model. Our data are closely fit by non-equilibrium evolution equations that involve at most three specimen-specific empirical parameters and that are based on the idea that stretch of axons and glial processes resists load-induced ECF pressure. PMID:25913604

  1. 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.

  2. Transient Dynamic Response and Failure of Sandwich Composite Structures under Impact Loading with Fluid Structure Interaction

    NASA Astrophysics Data System (ADS)

    Kwon, Y. W.; Violette, M. A.; McCrillis, R. D.; Didoszak, J. M.

    2012-12-01

    The objective of this study is to examine the Fluid Structure Interaction (FSI) effect on transient dynamic response and failure of sandwich composite structures under impact loading. The primary sandwich composite used in this study consisted of a 6.35 mm balsa core and a multi-ply symmetrical plain weave 6 oz E-glass skin. Both clamped sandwich composite plates and beams were studied using a uniquely designed vertical drop-weight testing machine. There were three impact conditions on which these experiments focused. The first of these conditions was completely dry (or air surrounded) testing. The second condition was completely water submerged. The final condition was also a water submerged test with air support at the backside of the plates. The tests were conducted sequentially, progressing from a low to high drop height to determine the onset and spread of damage to the sandwich composite when impacted with the test machine. The study showed the FSI effect on sandwich composite structures is very critical such that impact force, strain response, and damage size are generally much greater with FSI under the same impact condition. As a result, damage initiates at much lower impact energy conditions with the effect of FSI. Neglecting to account for FSI effects on sandwich composite structures results in very non-conservative analysis and design. Additionally, it was observed that the damage location changed for sandwich composite beams with the effect of FSI.

  3. High vacuum measurements and calibrations, molecular flow fluid transient effects

    DOE PAGESBeta

    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

  4. Evidence that transient changes in sudomotor output with cold and warm fluid ingestion are independently modulated by abdominal, but not oral thermoreceptors

    PubMed Central

    Morris, Nathan B.; Bain, Anthony R.; Cramer, Matthew N.

    2014-01-01

    Two studies were performed to 1) characterize changes in local sweat rate (LSR) following fluid ingestion of different temperatures during exercise, and 2) identify the potential location of thermoreceptors along the gastrointestinal tract that independently modify sudomotor activity. In study 1, 12 men cycled at 50% V̇o2peak for 75 min while ingesting 3.2 ml/kg of 1.5°C, 37°C, or 50°C fluid 5 min before exercise; and after 15, 30, and 45-min of exercise. In study 2, 8 men cycled at 50% V̇o2peak for 75 min while 3.2 ml/kg of 1.5°C or 50°C fluid was delivered directly into the stomach via a nasogastric tube (NG trials) or was mouth-swilled only (SW trials) after 15, 30, and 45 min of exercise. Rectal (Tre), aural canal (Tau), and mean skin temperature (Tsk); and LSR on the forehead, upper-back, and forearm were measured. In study 1, Tre, Tau, and Tsk were identical between trials, but after each ingestion, LSR was significantly suppressed at all sites with 1.5°C fluid and was elevated with 50°C fluid compared with 37°C fluid (P < 0.001). The peak difference in mean LSR between 1.5°C and 50°C fluid after ingestion was 0.29 ± 0.06 mg·min−1·cm−2. In study 2, LSR was similar between 1.5°C and 50°C fluids with SW trials (P = 0.738), but lower at all sites with 1.5°C fluid in NG trials (P < 0.001) despite no concurrent differences in Tre, Tau, and Tsk. These data demonstrate that 1) LSR is transiently altered by cold and warm fluid ingestion despite similar core and skin temperatures; and 2) thermoreceptors that independently and acutely modulate sudomotor output during fluid ingestion probably reside within the abdominal area, but not the mouth. PMID:24577060

  5. Measurement of transient surface temperatures during rubbing using infrared thermography

    NASA Astrophysics Data System (ADS)

    You, Tau; Yu, Jianwei; Yu, Xiaofen

    2013-10-01

    Infrared thermometer could provide IR radiance information to get the corresponding temperature as the machine is working. But the emissivity coefficient, which converts IR radiance to temperature, would vary with change of surface properties during rubbing, and this would bring dynamic error in measurement. In this study, we introduced a special tester, in the side of which compact IR thermometer are mounted. The thermometer enables us to measure contact surface temperature directly during tests of a rotating ring and a flat block which had a laser diode fixed under its contact surface. Based on Kirchhoff theory, the calculate model of the spectral emissivity is constructed. The normal emissivity at target region are measured through trigonometric ray consisted of InGaAsP laser source, PbSe detector and objective surface. So the temperature value from the IR thermometer could be corrected dynamically according to the real-time emissivity. The structure and the principle of the apparatus are described. The key technologies and the corresponding solution methods are briefly discussed. The error due to the rapid variations of emissivity value with change in contact conditions was shown, and it must be taken into consideration in radiometric temperature measurement in rubbing and could be especially useful in the verification of friction surface temperature predictions.

  6. Computer program simplifies transient and steady-state temperature prediction for complex body shapes

    NASA Technical Reports Server (NTRS)

    Giebler, K. N.

    1966-01-01

    Computer program evaluates heat transfer modes and calculates either the transient or steady-state temperature distributions throughout an object of complex shape when heat sources are applied to specified points on the object. It uses an electrothermal model to simulate the conductance, heat capacity, and temperature potential of the object.

  7. Surface temperature transients from pulsed laser heating of UO 2

    NASA Astrophysics Data System (ADS)

    Yagnik, S. K.; Olander, D. R.

    1988-07-01

    Surface heating of UO 2 by a pulsed laser was investigated theoretically and experimentally. Targets of solid uranium dioxide in vacuum were rapidly heated to peak temperatures of 3700 K, as measured by a fast-response automatic optical pyrometer. The measured target surface temperatures were compared with a one-dimensional heat transport model that accounts for conduction and melting in the solid and ablation and radiation from the surface. Congruent vaporization of UO 2 was assumed. The measured temporal and spatial characteristics of the laser beam as well as temperature-dependent physical and thermodynamic properties of UO 2 are used as input to the calculations. Agreement of the theory with the measurements was further validated by post-irradiation microscopic examination of the target surface. Additional tests were performed to assess qualitatively the attenuation of laser light and thermal radiation from the surface by the vapor blow-off from the target. This effect was found to be insignificant.

  8. Transient temperature and mixing times of quantum walks on cycles

    NASA Astrophysics Data System (ADS)

    Díaz, Nicolás; Donangelo, Raul; Portugal, Renato; Romanelli, Alejandro

    2016-07-01

    The definition of entanglement temperature for a quantum walk on a line is extended to N cycles, which are more amenable to a physical implementation. We show that, for these systems, there is a linear connection between the thermalization time and the mixing time and, also, that these characteristic times become insensitive to the system size when N is larger than a few units.

  9. Application of computational fluid dynamics and fluid structure interaction techniques for calculating the 3D transient flow of journal bearings coupled with rotor systems

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Yu, Guichang; Liu, Shulian; Zheng, Shuiying

    2012-09-01

    Journal bearings are important parts to keep the high dynamic performance of rotor machinery. Some methods have already been proposed to analysis the flow field of journal bearings, and in most of these methods simplified physical model and classic Reynolds equation are always applied. While the application of the general computational fluid dynamics (CFD)-fluid structure interaction (FSI) techniques is more beneficial for analysis of the fluid field in a journal bearing when more detailed solutions are needed. This paper deals with the quasi-coupling calculation of transient fluid dynamics of oil film in journal bearings and rotor dynamics with CFD-FSI techniques. The fluid dynamics of oil film is calculated by applying the so-called "dynamic mesh" technique. A new mesh movement approach is presented while the dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings. The proposed mesh movement approach is based on the structured mesh. When the journal moves, the movement distance of every grid in the flow field of bearing can be calculated, and then the update of the volume mesh can be handled automatically by user defined function (UDF). The journal displacement at each time step is obtained by solving the moving equations of the rotor-bearing system under the known oil film force condition. A case study is carried out to calculate the locus of the journal center and pressure distribution of the journal in order to prove the feasibility of this method. The calculating results indicate that the proposed method can predict the transient flow field of a journal bearing in a rotor-bearing system where more realistic models are involved. The presented calculation method provides a basis for studying the nonlinear dynamic behavior of a general rotor-bearing system.

  10. Feasibility Assessment of Thermal Barrier Seals for Extreme Transient Temperatures

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

    1998-01-01

    The assembly joints of modem solid rocket motor cases are generally sealed using conventional O-ring type seals. The 5500+ F combustion gases produced by rocket motors are kept a safe distance away from the seals by thick layers of phenolic insulation. Special compounds are used to fill insulation gaps leading up to the seals to prevent a direct flowpath to them. Design criteria require that the seals should not experience torching or charring during operation, or their sealing ability would be compromised. On limited occasions, NASA has observed charring of the primary O-rings of the Space Shuttle solid rocket nozzle assembly joints due to parasitic leakage paths opening up in the gap-fill compounds during rocket operation. NASA is investigating different approaches for preventing torching or charring of the primary O-rings. One approach is to implement a braided rope seal upstream of the primary O-ring to serve as a thermal barrier that prevents the hot gases from impinging on the O-ring seals. This paper presents flow, resiliency, and thermal resistance for several types of NASA rope seals braided out of carbon fibers. Burn tests were performed to determine the time to burn through each of the seals when exposed to the flame of an oxyacetylene torch (5500 F), representative of the 5500 F solid rocket motor combustion temperatures. Rope seals braided out of carbon fibers endured the flame for over six minutes, three times longer than solid rocket motor burn time. Room and high temperature flow tests are presented for the carbon seals for different amounts of linear compression. Room temperature compression tests were performed to assess seal resiliency and unit preloads as a function of compression. The thermal barrier seal was tested in a subscale "char" motor test in which the seal sealed an intentional defect in the gap insulation. Temperature measurements indicated that the seal blocked 2500 F combustion gases on the upstream side with very little temperature

  11. Transient fuel-pin temperature calculations using describing functions. Final report. [PWR; BWR

    SciTech Connect

    Guidotti, T.E.; Peddicord, K.L.; Nielsen, L.H.

    1982-02-01

    Temperature dependent properties make the transient thermal analysis of reactor fuel pins nonlinear. Traditionally, finite difference or finite element methods have been used to solve this system. An analytically based method is presented in which the transient temperature profiles are calculated using describing functions to characterize the system nonlinearities. In the past the describing functions approach has been used exclusively in the solution of ordinary differential equation systems. This study appears to be the first application of describing functions in the solution of partial differential equations.

  12. A Method for Calculating Transient Surface Temperatures and Surface Heating Rates for High-Speed Aircraft

    NASA Technical Reports Server (NTRS)

    Quinn, Robert D.; Gong, Leslie

    2000-01-01

    This report describes a method that can calculate transient aerodynamic heating and transient surface temperatures at supersonic and hypersonic speeds. This method can rapidly calculate temperature and heating rate time-histories for complete flight trajectories. Semi-empirical theories are used to calculate laminar and turbulent heat transfer coefficients and a procedure for estimating boundary-layer transition is included. Results from this method are compared with flight data from the X-15 research vehicle, YF-12 airplane, and the Space Shuttle Orbiter. These comparisons show that the calculated values are in good agreement with the measured flight data.

  13. Method of Generating Transient Equivalent Sink and Test Target Temperatures for Swift BAT

    NASA Technical Reports Server (NTRS)

    Choi, Michael K.

    2004-01-01

    The NASA Swift mission has a 600-km altitude and a 22 degrees maximum inclination. The sun angle varies from 45 degrees to 180 degrees in normal operation. As a result, environmental heat fluxes absorbed by the Burst Alert Telescope (BAT) radiator and loop heat pipe (LHP) compensation chambers (CCs) vary transiently. Therefore the equivalent sink temperatures for the radiator and CCs varies transiently. In thermal performance verification testing in vacuum, the radiator and CCs radiated heat to sink targets. This paper presents an analytical technique for generating orbit transient equivalent sink temperatures and a technique for generating transient sink target temperatures for the radiator and LHP CCs. Using these techniques, transient target temperatures for the radiator and LHP CCs were generated for three thermal environmental cases: worst hot case, worst cold case, and cooldown and warmup between worst hot case in sunlight and worst cold case in the eclipse, and three different heat transport values: 128 W, 255 W, and 382 W. The 128 W case assumed that the two LHPs transport 255 W equally to the radiator. The 255 W case assumed that one LHP fails so that the remaining LHP transports all the waste heat from the detector array to the radiator. The 382 W case assumed that one LHP fails so that the remaining LHP transports all the waste heat from the detector array to the radiator, and has a 50% design margin. All these transient target temperatures were successfully implemented in the engineering test unit (ETU) LHP and flight LHP thermal performance verification tests in vacuum.

  14. Numerical Model of Hydraulic Fracturing Fluid Transport in the Subsurface with Pressure Transient, Density Effects, and Imbibition

    NASA Astrophysics Data System (ADS)

    Birdsell, D.; Rajaram, H.; Dempsey, D.; Viswanathan, H.

    2014-12-01

    Understanding the transport of hydraulic fracturing (HF) fluid that is injected into the deep subsurface for shale gas extraction is important to ensure that shallow drinking water aquifers are not contaminated from an environmental and public health perspective and to understand formation damage from an oil and gas production perspective. Upward pressure gradients, permeable pathways such as faults or improperly abandoned wellbores, and the density contrast of the HF fluid to the surrounding brine encourages upward HF fluid migration. In contrast, the very low shale permeability and the imbibition of water into partially-saturated shale may sequester much of the HF fluid. Using the Finite Element Heat and Mass Transfer Code (FEHM), single-phase flow and transport simulations are performed to quantify how much HF fluid is removed via the wellbore as flowback and produced water and how much reaches overlying aquifers; imbibition is calculated with a semi-analytical one-dimensional solution and treated as a sink term. The travel time for HF fluid to reach the shallow aquifers is highly dependent on the amount of water imbibed and the suction applied to the well. If imbibition rates and suction are small, the pressure transient due to injection and the density contrast allows rapid upward plume migration at early times. The density contrast diminishes considerably within tens to hundreds of years as mixing occurs. We present estimates of HF fluid migration to shallow aquifers during the first 1,000 years after hydraulic fracturing begins for ranges of subsurface properties.

  15. Transient solution for a plane-strain fracture driven by a shear-thinning, power-law fluid

    NASA Astrophysics Data System (ADS)

    Garagash, D. I.

    2006-12-01

    This paper analyses the problem of a fluid-driven fracture propagating in an impermeable, linear elastic rock with finite toughness. The fracture is driven by injection of an incompressible viscous fluid with power-law rheology. The relation between the fracture opening and the internal fluid pressure and the fracture propagation in mobile equilibrium are described by equations of linear elastic fracture mechanics (LEFM), and the flow of fluid inside the fracture is governed by the lubrication theory. It is shown that for shear-thinning fracturing fluids, the fracture propagation regime evolves in time from the toughness- to the viscosity-dominated regime. In the former, dissipation in the viscous fluid flow is negligible compared to the dissipation in extending the fracture in the rock, and in the later, the opposite holds. Corresponding self-similar asymptotic solutions are given by the zero-viscosity and zero-toughness (J. Numer. Anal. Meth. Geomech. 2002; 26:579-604) solutions, respectively. A transient solution in terms of the crack length, the fracture opening, and the net fluid pressure, which describes the fracture evolution from the early-time (toughness-dominated) to the large-time (viscosity-dominated) asymptote is presented and some of the implications for the practical range of parameters are discussed. Copyright

  16. Circular radiation heat shields with temperature dependent emissivities: transient and steady-state analyses

    NASA Astrophysics Data System (ADS)

    Yu, H.; Li, X.; Hu, S.; Li, Z.; Chen, A.

    2016-03-01

    Radiation heat loss is an important type of heat loss in thermal systems. In this work, a numerical study of the transient response of two circular radiation heat shields inserted between two parallel and circular surfaces of emissivities ɛ1 and ɛ2 is presented. The same dimensions have been assumed for the two main radiating surfaces and the two radiation shields. The radiation shields are assumed to have different emissivities on their top (ɛ3 and ɛ5) and bottom ( ɛ4 and ɛ6) surfaces, and both are assumed to be different but linear functions of temperature. A specific configuration is investigated in detail to highlight the transient temperature and heat transfer characteristics of the system. Some new results for the transient temperature and heat transfer characteristics of the system such as the effect of shield location, shield emissivities, the temperature dependence of shield emissivities, system dimensions, temperatures of the hot and cold surfaces and emissivities of the hot and cold surfaces are presented for future references. It has been observed that increasing the temperature of the first radiation shield by changing a parameter such as surface emissivity or distance between the radiation shield or the temperature of the hot surface, will not necessarily decrease the temperature of the second radiation shield.

  17. Transient tachypnea - newborn

    MedlinePlus

    TTN; Wet lungs - newborns; Retained fetal lung fluid; Transient RDS; Prolonged transition; Neonatal - transient tachypnea ... As the baby grows in the womb, the lungs make a special fluid. This fluid fills the ...

  18. Constraints on the transient climate response from observed global temperature and ocean heat uptake

    NASA Astrophysics Data System (ADS)

    Knutti, Reto; Tomassini, Lorenzo

    2008-05-01

    Projections of future transient global temperature increase in climate models for a known forcing depend on the strength of the atmospheric feedbacks and the rate of transient ocean heat uptake. A Bayesian framework and an intermediate complexity climate model are used to calculate a probability density function (PDF) of the transient climate response (TCR), constrained by observations of global surface warming and ocean heat uptake. The PDF constrained by observations is wider than the TCR range of current climate models, and has a slightly lower mean. Uncertainties in the observed ocean warming are shown to potentially affect the TCR. It is proposed, however, that even if models were found to overestimate ocean heat uptake, correcting that bias would lead to revisions in surface temperature projections over the twenty-first century that are smaller than the uncertainties introduced by poorly quantified atmospheric feedbacks.

  19. TEMLOPI/V.2: a computer program for estimation of fully transient temperatures in geothermal wells during circulation and shut-in

    NASA Astrophysics Data System (ADS)

    Espinosa-Paredes, G.; Garcia, A.; Santoyo, E.; Hernandez, I.

    2001-04-01

    This paper describes the development, validation and application of the TEMLOPI/V.2 computer program. This program is a useful tool for estimating in-situ the transient temperature distribution of the fluids employed for drilling geothermal wells. TEMLOPI/V.2 is based on a mathematical model which is developed to consider two-dimensional transient heat transfer during drilling and shut-in conditions in and around a geothermal well. The solution of the partial differential equations is based on the finite-difference technique with an implicit scheme. This scheme serves to demonstrate the numerical solution procedure. Each radial grid node is placed in a different thermal region: flow inside the pipe, metal pipe wall, flow inside annulus, and the surrounding formation. The program was written in FORTRAN 77 using modular programming and runs on most IBM compatible personal computers. The software code, its architecture, input and output files, the solution algorithm, flow diagrams and source programs are described in detail. From validation tests, computed temperatures differ by less than 5°C from analytically obtained temperatures. Comparison of results from the fully transient TEMLOPI/V.2 simulator and the pseudo-transient version, TEMLOPI/V.1, with measured data shows that the fully transient model provides better results. Application of TEMLOPI/V.2 is demonstrated in a practical application study of well EAZ-2 from Los Azufres Mexican geothermal field.

  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. 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.

  2. Effect of irrigation fluid temperature on body temperature during arthroscopic elbow surgery in dogs

    PubMed Central

    Thompson, K.R.; MacFarlane, P.D.

    2013-01-01

    This prospective randomised clinical trial evaluated the effect of warmed irrigation fluid on body temperature in anaesthetised dogs undergoing arthroscopic elbow surgery. Nineteen dogs undergoing elbow arthroscopy were included in the study and were randomly allocated to one of two groups. Group RT received irrigation fluid at room temperature (RT) while dogs in group W received warmed (W) irrigation fluid (36°C). A standardised patient management and anaesthetic protocol was used and body temperature was measured at four time points; (T1) pre-anaesthetic examination, (T2) arrival into theatre, (T3) end of surgery and (T4) arrival into recovery. There was no significant difference in body temperature at any time point between the groups. The mean overall decrease in body temperature between pre-anaesthetic examination (T1) and return to the recovery suite (T4) was significant in both groups, with a fall of 1.06±0.58°C (p<0.001) in group RT and 1.53±0.76°C (p<0.001) group W. There was no significant difference between the groups. At the end of surgery (T3) 4/19 (21.1%) of dogs were hypothermic (<37°C). The addition of warmed irrigation fluids to a temperature management protocol in dogs undergoing elbow arthroscopy during general anaesthesia did not lead to decreased temperature losses. PMID:26623323

  3. Effects of temperature on performance of a compressible magnetorheological fluid damper-liquid spring suspension system

    NASA Astrophysics Data System (ADS)

    McKee, Michael; Wang, Xiaojie; Gordaninejad, Faramarz

    2011-03-01

    A compact compressible magnetorheological (MR) fluid damper-liquid spring (CMRFD-LS) suspension system is designed, developed and tested. The performances of the CMRFD-LS are investigated under room temperature. However, MR fluids are temperature dependent. The effect of temperature is observed in both the viscosity and the compressibility of the MR fluid. This study is to experimentally determine how temperature affects the performance of a CMRFD-LS device. A test setup is developed to measure the stiffness and energy dissipated by the system under various frequency loadings, magnetic fields and temperatures. The experimental results demonstrate that both the stiffness and the energy dissipated by the CMRFD-LS are inversely related to the temperature of the MR fluid. These changes in damper characteristics show that the compressibility of MR fluid is proportional to the fluid temperature, while the viscosity of the MR fluid is inversely related to the fluid temperature.

  4. COMPARING SIMULATED AND EXPERIMENTAL HYSTERETIC TWO- PHASE TRANSIENT FLUID FLOW PHENOMENA

    EPA Science Inventory

    A hysteretic model for two-phase permeability (k)-saturation (S)-pressure (P) relations is outlined that accounts for effects of nonwetting fluid entrapment. The model can be employed in unsaturated fluid flow computer codes to predict temporal and spatial fluid distributions. Co...

  5. Analytical solution and computer program (FAST) to estimate fluid fluxes from subsurface temperature profiles

    NASA Astrophysics Data System (ADS)

    Kurylyk, Barret L.; Irvine, Dylan J.

    2016-02-01

    This study details the derivation and application of a new analytical solution to the one-dimensional, transient conduction-advection equation that is applied to trace vertical subsurface fluid fluxes. The solution employs a flexible initial condition that allows for nonlinear temperature-depth profiles, providing a key improvement over most previous solutions. The boundary condition is composed of any number of superimposed step changes in surface temperature, and thus it accommodates intermittent warming and cooling periods due to long-term changes in climate or land cover. The solution is verified using an established numerical model of coupled groundwater flow and heat transport. A new computer program FAST (Flexible Analytical Solution using Temperature) is also presented to facilitate the inversion of this analytical solution to estimate vertical groundwater flow. The program requires surface temperature history (which can be estimated from historic climate data), subsurface thermal properties, a present-day temperature-depth profile, and reasonable initial conditions. FAST is written in the Python computing language and can be run using a free graphical user interface. Herein, we demonstrate the utility of the analytical solution and FAST using measured subsurface temperature and climate data from the Sendia Plain, Japan. Results from these illustrative examples highlight the influence of the chosen initial and boundary conditions on estimated vertical flow rates.

  6. Comparison of digital holographic interferometry and constant temperature anemometry for measurement of temperature field in fluid

    NASA Astrophysics Data System (ADS)

    Doleček, Roman; Psota, Pavel; Lédl, Vít.; Vít, Tomáś; Dančová, Petra; Kopecký, Václav

    2015-05-01

    The presented paper shows possibility of using digital holographic interferometry (DHI) for temperature field measurement in moving fluids. This method uses a modified Twymann-Green setup having double sensitivity instead of commonly used Mach-Zehnder type of interferometer in order to obtain sufficient phases change of the field. On the other hand this setup is not light efficient as Mach-Zehnder interferometer. For measurement of the fast periodical phenomenon is not necessary to use always the high speed camera. One can consider this field to coherent phenomenon. With employing one digital camera synchronized to periodic field and external triggered one can capture whole period of the phenomenon. However the projections form one viewing direction of asymmetrical temperature field maybe misguided. Hence for sufficient examination of the asymmetrical field one should capture a large number of the phenomenon's projections from different viewing directions. This projections are later used for 3D tomographic reconstruction of the whole temperature field and its time evolution. One of the commonly used method for temperature field measurement in moving fluids is hot wire method - constant temperature anemometry (CTA). In contrast to whole field measurement of DHI it is an invasive point temperature measurement method. One of the limiting factor of using CTA in moving fluids is frequency of temperature changes. This changes should not exceed 1 kHz. This limitation could be overcome by using of optical methods such as DHI. The results of temperature field measurement achieved by both method are compared in the paper.

  7. Thermal transient anemometer

    DOEpatents

    Bailey, J.L.; Vresk, J.

    1989-07-18

    A thermal transient anemometer is disclosed having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe. 12 figs.

  8. Thermal transient anemometer

    DOEpatents

    Bailey, James L.; Vresk, Josip

    1989-01-01

    A thermal transient anemometer having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe.

  9. High-temperature organic-fluid fouling unit

    SciTech Connect

    Kuru, W.C.; Panchal, C.B.

    1997-06-01

    A new type of fouling unit is developed for high-temperature (500 C) and high-pressure (70 atmosphere) fouling experiments by modifying a commercial autoclave. Key modifications are the installation of a helical impeller in a flow tube and a fouling probe in the autoclave to simulate the fluid dynamics and heat transfer of typical heat-exchange equipment. A calibration technique is described, and fouling results are presented for experimental runs with indene and kerosene. The results are compared with those obtained using other types of fouling test units. Other potential applications of the fouling unit, such as corrosion and micro-scale reaction experiments, are discussed.

  10. Transient response of sheared magnetic powder excited by a stepwise magnetic field and its comparison with ER and MR fluids

    NASA Astrophysics Data System (ADS)

    Chen, KaiKai; Tian, Yu; Shan, Lei; Jiang, Jile

    2013-09-01

    The transient shear behavior of magnetic powder (MP) excited by a stepwise magnetic field in a rotational magnetic powder clutch (MPC) was experimentally studied. The experiment showed that the stable shear stress was approximately proportional to the applied magnetic flux density. The characteristic rising time of the shear stress was independent of the strength of the magnetic field and was affected by the shear rate. It took less than 0.1 s for the shear stress to rise to 63% (1 - e-1) of the stable value. The transient shear stress rising process consisted of two subprocesses: the chain forming process which was less than 100 ms, and the chain coarsening process lasting for dozens of seconds. Upon switching the field off, the shear stress fell rapidly to zero in 0.1 s. Control methods to improve the transient response time of the MPC were discussed and experimentally verified: applying a low voltage in advance; applying a high level voltage for the torque to rise to the target torque and then a desired voltage. These transient characteristics of MP were compared with those of electrorheological (ER) and magneto-rheological (MR) fluids and actuators. The study provides a better understanding of MP excited by a magnetic field and the implications for application.

  11. Low Temperature Transient Performance of Polymer Organic Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Burnett, Karl

    2009-11-01

    Polymer Organic Light-Emitting Diodes (p-OLEDs) are conjugated polymers that conduct electric charges, enabling their use as semiconductors. Typical applications for p-OLEDs include high-resolution, high-efficiency displays, and when printed onto plastic substrates, thin and flexible patterned light sources such as vehicle dashboard displays and telephone keypads. We are investigating turn-on and turn-off transient effects in p-OLEDs that vary with temperature and the electrical driver. We have found that the turn-on transient is thermally activated, that light output is immediately proportional to current flow into the device, and that light emission continues from the device even after bias is removed. When these phenomena are fully characterized, they may explain transient effects seen in previous work, help describe the activation energies and rate kinetics in the device, and broaden the range of environments in which p-OLED devices may be used.

  12. An earthquake transient method for pebble-bed reactors and a fuel temperature model for TRISO fueled reactors

    NASA Astrophysics Data System (ADS)

    Ortensi, Javier

    This investigation is divided into two general topics: (1) a new method for analyzing the safe shutdown earthquake event in a pebble bed reactor core, and (2) the development of an explicit tristructural-isotropic fuel model for high temperature reactors. The safe shutdown earthquake event is one of the design basis accidents for the pebble bed reactor. The new method captures the dynamic geometric compaction of the pebble bed core. The neutronic and thermal-fluids grids are dynamically re-meshed to simulate the re-arrangement of the pebbles in the reactor during the earthquake. Results are shown for the PBMR-400 assuming it is subjected to the Idaho National Laboratory's design basis earthquake. The study concludes that the PBMR-400 can safely withstand the reactivity insertions induced by the slumping of the core and the resulting relative withdrawal of the control rods. This characteristic stems from the large negative Doppler feedback of the fuel. This Doppler feedback mechanism is a major contributor to the passive safety of gas-cooled, graphite-moderated, high-temperature reactors that use fuel based on TRISO particles. The correct prediction of the magnitude and time-dependence of this feedback effect is essential to the conduct of safety analyses for these reactors. An explicit TRISO fuel temperature model named THETRIS has been developed in this work and incorporated in the CYNOD-THERMIX-KONVEK suite of coupled codes. The new model yields similar results to those obtained with more complex methods, requiring multi-TRISO calculations within one control volume. The performance of the code during fast and moderately-slow transients is verified. These analyses show how explicit TRISO models improve the predictions of the fuel temperature, and consequently, of the power escalation. In addition, a brief study of the potential effects on the transient behavior of high-temperature reactors due to the presence of a gap inside the TRISO particles is included

  13. Rayleigh light scattering measurements of transient gas temperature in a rapid chemical vapor deposition reactor

    SciTech Connect

    Horton, J.F.; Peterson, J.E.

    2000-02-01

    A laser-induced Rayleigh light scattering (RLS) system was used to measure transient gas temperatures in a simulated rapid chemical vapor deposition (RCVD) reactor. The test section geometry was an axisymmetric jet of carrier gas directed down, impinging on a heated water surface. RLS was used to measure instantaneous gas temperature at several locations above the wafer as it was heated from room temperature to 475 K. Gas flow rate and wafer temperature correspond to jet Reynolds number Re{sub i} = 60, wafer maximum Grashof number Gr{sub H} = 4.4 x 10{sup 6}, and a maximum mixed convection parameter Gr{sub H}/Re{sub i}{sup 2} = 1200; all conditions typical of impinging jet reactors common in the numerical literature. Uncertainty of RLS transient temperature from a propagated error analysis was {+-}2--4 K. Peak gas temperature fluctuations were large (in the order of 25 to 75 C). Both flow visualization and RLS measurements showed that the flow field was momentum dominated prior to heating initiation, but became unstable by Gr{sub H}/Re{sub i}{sup 2} = 5. It then consisted of buoyancy-induced plumes and recirculations. Up to the peak wafer temperature, the flow field continued to be highly three-dimensional, unsteady, and dominated by buoyancy. RLS measurements are shown to provide information on carrier gas instantaneous temperature and flow field stability, both critical issues in RCVD processing.

  14. Method and apparatus for controlling combustor temperature during transient load changes

    DOEpatents

    Clingerman, Bruce J.; Chalfant, Robert W.

    2002-01-01

    A method and apparatus for controlling the temperature of a combustor in a fuel cell apparatus includes a fast acting air bypass valve connected in parallel with an air inlet to the combustor. A predetermined excess quantity of air is supplied from an air source to a series connected fuel cell and combustor. The predetermined excess quantity of air is provided in a sufficient amount to control the temperature of the combustor during start-up of the fuel processor when the load on the fuel cell is zero and to accommodate any temperature transients during operation of the fuel cell.

  15. Biodegradation of aircraft deicing fluids in soil at low temperatures.

    PubMed

    Klecka, G M; Carpenter, C L; Landenberger, B D

    1993-06-01

    The effects of substrate concentration and temperature on the biodegradation of five different aircraft deicing fluids was examined in soil samples obtained from an area adjacent to an airport runway. The principle organic constituents, which included ethylene, propylene, and diethylene glycols, were shown to be mineralized to carbon dioxide in soil microcosms incubated at temperatures ranging from -2 to 25 degrees C. No lag period was observed, and biological transformation of the test chemicals began immediately after addition to the soil. Glycol biodegradation was observed in soil at concentrations ranging from 392 to 5278 mg/kg, suggesting that high levels of the deicing fluids are unlikely to be inhibitory to soil microorganisms. All three glycols were readily degraded in soil at 8 and 25 degrees C, regardless of whether the compounds were present singly or as a component of a mixture. In addition, the biodegradation rates for the three compounds were very similar. Average rates were in the range of 19.7 to 27.0 mg/kg soil per day at 8 degrees C and 66.3 to 93.3 mg/kg soil per day for soil samples incubated at 25 degrees C. The soil biodegradation rates were reduced in soils at -2 degrees C to between 2.3 and 4.5 mg/kg per day. Based on these results, biodegradation is expected to play a major role in removing residual levels of glycols from soils adjacent to airport taxiways and runways. PMID:7691522

  16. The effect of transient temporal pulse shape on surface temperature and tungsten damage

    NASA Astrophysics Data System (ADS)

    Yu, J. H.; De Temmerman, G.; Doerner, R. P.; Pitts, R. A.; van den Berg, M. A.

    2015-09-01

    The plasma-facing components (PFCs) in future fusion devices such as ITER will receive intense transient heat fluxes from plasma instabilities, such as edge localized modes (ELMs) and disruptions, which will limit material lifetime. The energy density and transient pulse duration are typically used to characterize the PFC damage threshold. However, these parameters are not sufficient to define a damage threshold, because different transient pulse shapes with the same energy density and same pulse duration produce different peak surface temperatures (and thus stresses, which ultimately determine material damage). The surface temperature and damage of tungsten (the material to be used for the ITER divertor target armor) in the form of surface roughening and melting are investigated using various temporal pulse shapes from an Nd:YAG laser in the PISCES-B facility. The heat flux factor is examined and shown to be an inadequate parameter to characterize the temperature rise except for square temporal pulse shapes. For ELM-like heat pulses, the long tail in the temporal shape results in a lower peak surface temperature and less damage compared to a symmetric triangle pulse with equal energy density.

  17. Transient formation characteristics of temperature stratified flow in a horizontal water pipe with an injection of hot water from a hole of a pipe

    SciTech Connect

    Okinotani, Takeshi; Ozoe, Hiroyuki

    1999-07-01

    Temperature stratified flow was numerically analyzed in a horizontal pipe. Initially cold water is running and developed in a pipe. From a part of a pipe wall, hot water is injected. Subsequent transient velocity and temperature stratification process was numerically analyzed. This process is a model for such transfer phenomena as follows, i.e., blowing of fresh air into a long tunnel, replacing process of hazardous fluids from a pipeline of an industrial plant with safer fluids, ventilation of a large construction house or ducts, transient combustion process in a tunnel or huge duct, transient flow and temperature characteristics in a canal or river with multiple sub channels. These various cases become more complicated and more serious for the larger scale systems. Temperature stratified flow is everywhere established which makes the prediction difficult. This paper presents transient three-dimensional numerical analyses for a horizontal pipe in which laminar cold water runs steadily. Hot water is injected from a lower side corner of a pipe. Model equations consist of fully three-dimensional balance equations in a cylindrical coordinate. Total tube length computed is 10 times of a pipe diameter d{sub 0}. Hot water inlet hole is 0.4d{sub 0} long in an axial direction and {pi}d{sub 0}/8 in a circumferential direction near the entrance of the system. Reynolds number in a pipe is 1000. Reynolds number of the hot water at the injection hole is 447. Grashof number based on the temperature difference is 5 x 10{sup 7} and Pr = 5.41. Transient three-dimensional velocity profiles and isotherms are presented. The instantaneous water temperature represents oscillatory fluctuation depending on the level in a pipe and on the axial distance from the injection hole. For the tube diameter 0.1m, an average temperature arrived a quasi-steady state after 5 minutes with strong temperature stratification even at 1m from an injection hole. Near the injection hole, hot water makes

  18. Predicting the Reliability of Ceramics Under Transient Loads and Temperatures With CARES/Life

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Jadaan, Osama M.; Palfi, Tamas; Baker, Eric H.

    2003-01-01

    A methodology is shown for predicting the time-dependent reliability of ceramic components against catastrophic rupture when subjected to transient thermomechanical loads (including cyclic loads). The methodology takes into account the changes in material response that can occur with temperature or time (i.e., changing fatigue and Weibull parameters with temperature or time). This capability has been added to the NASA CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code. The code has been modified to have the ability to interface with commercially available finite element analysis (FEA) codes executed for transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

  19. 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

  20. Transient modeling of the thermohydraulic behavior of high temperature heat pipes for space reactor applications

    NASA Technical Reports Server (NTRS)

    Hall, Michael L.; Doster, Joseph M.

    1986-01-01

    Many proposed space reactor designs employ heat pipes as a means of conveying heat. Previous researchers have been concerned with steady state operation, but the transient operation is of interest in space reactor applications due to the necessity of remote startup and shutdown. A model is being developed to study the dynamic behavior of high temperature heat pipes during startup, shutdown and normal operation under space environments. Model development and preliminary results for a hypothetical design of the system are presented.

  1. Ductile creep and compaction: A mechanism for transiently increasing fluid pressure in mostly sealed fault zones

    USGS Publications Warehouse

    Sleep, N.H.; Blanpied, M.L.

    1994-01-01

    A simple cyclic process is proposed to explain why major strike-slip fault zones, including the San Andreas, are weak. Field and laboratory studies suggest that the fluid within fault zones is often mostly sealed from that in the surrounding country rock. Ductile creep driven by the difference between fluid pressure and lithostatic pressure within a fault zone leads to compaction that increases fluid pressure. The increased fluid pressure allows frictional failure in earthquakes at shear tractions far below those required when fluid pressure is hydrostatic. The frictional slip associated with earthquakes creates porosity in the fault zone. The cycle adjusts so that no net porosity is created (if the fault zone remains constant width). The fluid pressure within the fault zone reaches long-term dynamic equilibrium with the (hydrostatic) pressure in the country rock. One-dimensional models of this process lead to repeatable and predictable earthquake cycles. However, even modest complexity, such as two parallel fault splays with different pressure histories, will lead to complicated earthquake cycles. Two-dimensional calculations allowed computation of stress and fluid pressure as a function of depth but had complicated behavior with the unacceptable feature that numerical nodes failed one at a time rather than in large earthquakes. A possible way to remove this unphysical feature from the models would be to include a failure law in which the coefficient of friction increases at first with frictional slip, stabilizing the fault, and then decreases with further slip, destabilizing it. ?? 1994 Birkha??user Verlag.

  2. Simulation of transient fluid flow in mold region during steel continuous casting

    NASA Astrophysics Data System (ADS)

    Liu, R.; Thomas, B. G.; Sengupta, J.

    2012-07-01

    A system of models has been developed to study transient flow during continuous casting and applied to simulate an event of multiple stopper-rod movements. It includes four sub-models to incorporate different aspects in this transient event. A three-dimensional (3-D) porous-flow model of the nozzle wall calculates the rate argon gas flow into the liquid steel, and the initial mean bubble size is estimated. Transient CFD models simulate multiphase flow of steel and gas bubbles in the Submerged Entry Nozzle (SEN) and mold and have been validated with experimental data from both nail dipping and Sub-meniscus Velocity Control (SVC) measurements. To obtain the transient inlet boundary conditions for the simulation, two semi-empirical models, a stopper-rod-position based model and a metal-level-based model, predict the liquid steel flow rate through the SEN based on recorded plant data. Finally the model system was applied to study the effects of stopper rod movements on SEN/mold flow patterns. Meniscus level fluctuations were calculated using a simple pressure method and compared well with plant measurements. Insights were gained from the simulation results to explain the cause of meniscus level fluctuations and the formation of sliver defects during stopper rod movements.

  3. A New Correction Technique for Strain-Gage Measurements Acquired in Transient-Temperature Environments

    NASA Technical Reports Server (NTRS)

    Richards, W. Lance

    1996-01-01

    Significant strain-gage errors may exist in measurements acquired in transient-temperature environments if conventional correction methods are applied. As heating or cooling rates increase, temperature gradients between the strain-gage sensor and substrate surface increase proportionally. These temperature gradients introduce strain-measurement errors that are currently neglected in both conventional strain-correction theory and practice. Therefore, the conventional correction theory has been modified to account for these errors. A new experimental method has been developed to correct strain-gage measurements acquired in environments experiencing significant temperature transients. The new correction technique has been demonstrated through a series of tests in which strain measurements were acquired for temperature-rise rates ranging from 1 to greater than 100 degrees F/sec. Strain-gage data from these tests have been corrected with both the new and conventional methods and then compared with an analysis. Results show that, for temperature-rise rates greater than 10 degrees F/sec, the strain measurements corrected with the conventional technique produced strain errors that deviated from analysis by as much as 45 percent, whereas results corrected with the new technique were in good agreement with analytical results.

  4. Monotonic and transient creep experiments for single phase gamma TiAl at intermediate temperatures

    SciTech Connect

    Lu, M.; Hemker, K.J.

    1997-12-31

    Monotonic creep experiments (constant stress and constant temperature) of a single phase {gamma} Ti{sub 47}Al{sub 51}Mn{sub 2} were conducted within a temperature region where the yield stress anomaly is observed (500 C--600 C). The creep strength was found to have a normal temperature dependence. In addition to the monotonic creep experiments, temperature change experiments were performed. The creep activation energy obtained by the transient experiments was found to be significantly lower than that obtained from the monotonic experiments. TEM observations indicate that the microstructure evolves throughout creep, and no evidence of the formation of subgrains was observed. Instead, the mobility and the multiplication of ordinary dislocations were found to play a dominant role in intermediate temperature creep of single phase {gamma}TiAl.

  5. Estimation of changes in dynamic hydraulic force in a magnetically suspended centrifugal blood pump with transient computational fluid dynamics analysis.

    PubMed

    Masuzawa, Toru; Ohta, Akiko; Tanaka, Nobuatu; Qian, Yi; Tsukiya, Tomonori

    2009-01-01

    The effect of the hydraulic force on magnetically levitated (maglev) pumps should be studied carefully to improve the suspension performance and the reliability of the pumps. A maglev centrifugal pump, developed at Ibaraki University, was modeled with 926 376 hexahedral elements for computational fluid dynamics (CFD) analyses. The pump has a fully open six-vane impeller with a diameter of 72.5 mm. A self-bearing motor suspends the impeller in the radial direction. The maximum pressure head and flow rate were 250 mmHg and 14 l/min, respectively. First, a steady-state analysis was performed using commercial code STAR-CD to confirm the model's suitability by comparing the results with the real pump performance. Second, transient analysis was performed to estimate the hydraulic force on the levitated impeller. The impeller was rotated in steps of 1 degrees using a sliding mesh. The force around the impeller was integrated at every step. The transient analysis revealed that the direction of the radial force changed dynamically as the vane's position changed relative to the outlet port during one circulation, and the magnitude of this force was about 1 N. The current maglev pump has sufficient performance to counteract this hydraulic force. Transient CFD analysis is not only useful for observing dynamic flow conditions in a centrifugal pump but is also effective for obtaining information about the levitation dynamics of a maglev pump. PMID:19894088

  6. Steady state and transient temperature distributions in the human thigh covered with a cooling pad

    NASA Technical Reports Server (NTRS)

    Leo, R. J.; Shitzer, A.; Chato, J. C.; Hertig, B. A.

    1971-01-01

    An analytical and experimental study was done on the performance of cooling pads attached to a human thigh. Each cooling pad consisted of a long, water cooled tube formed into a serpentine shape with uniform spacing between the parallel sections. The analytical work developed a cylindrical model for the human thigh. The transient times predicted by this model ranged from 25 to 80 minutes, which is reasonably close to the experimental results. Calculated and measured steady state temperature profiles were in fair agreement. The transient times associated with a change from a high metabolic rate of 1800 Btu/hr (528 w) to a low level of 300 Btu/hr (88 w), were found to be about 120 minutes. A change from 300 Btu/hr (264 w) to 300 Btu/hr (88 w) resulted in 90 to 100 minute transients. However, the transient times for a change in metabolic rate in the opposite direction from 300 Btu/hr (88 w) to 1800 Btu/hr (528 w) were 40 to 60 minutes.

  7. Transient simulations of large-scale hydrogeological processes causing temperature and salinity anomalies in the Tiberias Basin

    NASA Astrophysics Data System (ADS)

    Magri, Fabien; Inbar, Nimrod; Siebert, Christian; Rosenthal, Eliahu; Guttman, Joseph; Möller, Peter

    2015-01-01

    Hot and salty waters occur in the surroundings of the Lake Tiberias. Transient numerical simulations of thermally-driven flow without salinity effects show that mixed convection can explain the upsurge of thermal waters through permeable faults and the high temperature gradient in the Lower Yarmouk Gorge (LYG). It turns out that by including salinity effects, the flow patterns differ from those of a purely thermal regime because heavy brines dampen upward buoyant flow and convective cells. Accordingly, the fault permeability had to be increased to restore a good fit with the measured temperatures. This further supports the hypothesis that the high temperature gradient in the LYG is likely due to fractures or faults in that area. The thermohaline simulations also suggest that the derivatives of relic seawater brines are the major source of salinity. Deep brines leaching salt diapirs cannot reach the surface. However, the presence of local shallower salt bodies below the lake can potentially contribute to the salinity of the western spring and well waters, though in very small amount. This is in agreement with geochemical data according to which the major source of the brines of the Tiberias Basin represents seawater evaporation brines. Besides being of importance for understanding the hydrogeological processes that salinize Lake Tiberias, the presented simulations provide a real-case example illustrating large-scale fluid patterns due to only one source of buoyancy (heat) and those that are additionally coupled to salinity.

  8. Fluid simulations of toroidal ion temperature gradient turbulence

    SciTech Connect

    Sandberg, I.; Isliker, H.; Pavlenko, V.P.; Hizanidis, K.; Vlahos, L.

    2006-02-15

    The evolution of the toroidal ion temperature gradient mode instability is numerically studied by using the equations based on the standard reactive fluid model. The long-term dynamics of the instability are investigated using random-phase, small-amplitude fluctuations for initial conditions. The main events during the evolution of the instability that lead to the formation of large-scale coherent structures are described and the role of the dominant nonlinearities is clarified. The polarization drift nonlinearity leads to the inverse energy cascade while the convective ion heat nonlinearity is responsible for the saturation of the instability. Finally, the sensitivity of the saturated state to the initial plasma conditions is examined.

  9. Role of pore fluid pressure on transient strength changes and fabric development during serpentine dehydration at mantle conditions: Implications for subduction-zone seismicity

    NASA Astrophysics Data System (ADS)

    Proctor, Brooks; Hirth, Greg

    2015-07-01

    To further investigate the dehydration embrittlement hypothesis and its possible link to subduction-zone seismicity, we conducted deformation experiments on antigorite serpentinite in a Griggs-type apparatus at conditions below and above antigorite stability. Temperature ramps (crossing the antigorite thermal stability) were used in conjunction with a new experimental method that allows fluid produced during dehydration reactions to be drained, partially drained or undrained. During temperature ramps, weakening coupled with transient slip initiated at ˜ 650 °C, coincident with the predicted phase transition of antigorite to olivine and talc at ˜ 1 GPa. The weakening-rate and steady-state strength were dependent on drainage conditions; undrained samples weakened over a few minutes and supported the lowest shear stress (˜ 50 MPa), while drained samples weakened over a few hours and supported the highest shear stress (˜ 210 MPa). The coefficient of friction (shear stress over normal stress) in drained samples decreased from ˜0.4 to ˜0.16 after the temperature ramp. The strengths of samples that were first annealed at 700 °C for ˜ 12 h, then deformed, were similar to those observed in the temperature ramp experiments. Strain localization along fractures occurred in all samples during temperature ramping, regardless of the drainage conditions. However, microstructural observations indicate deformation by ductile mechanisms at higher strain under both undrained and drained conditions. The rheology and microstructures suggest dehydrating serpentinite deforms via semibrittle flow with grain-scale ductile deformation more active at high pore fluid pressures. Our results suggest that earthquakes in serpentinized mantle do not nucleate as a direct result of unstable frictional sliding along fractures generated at the onset of dehydration reactions.

  10. Range of applicability of the linear fluid slosh theory for predicting transient lateral slosh and roll stability of tank vehicles

    NASA Astrophysics Data System (ADS)

    Kolaei, Amir; Rakheja, Subhash; Richard, Marc J.

    2014-01-01

    An analytical model is developed to study the transient lateral sloshing in horizontal cylindrical containers assuming inviscid, incompressible and irrotational flows. The model is derived by implementing the linearized free-surface boundary condition and bipolar coordinate transformation, resulting in a truncated system of linear ordinary differential equations, which is numerically solved to determine the fluid velocity potentials followed by the hydrodynamic forces and moment. The model results are compared with those obtained from the multimodal solution. The free-surface elevation and hydrodynamic coefficients are also compared with the reported experimental and analytical data as well as numerical simulations to establish validity of the model. The capability of the model for predicting non-resonant slosh is also evaluated using the critical free-surface amplitude. The model validity is further illustrated by comparing the transient liquid slosh responses of a partially filled tank subject to steady lateral acceleration characterizing a vehicle turning maneuver with those obtained from fully nonlinear CFD simulations and pendulum models. It is shown that the linear slosh model yields more accurate prediction of dynamic slosh than the pendulum models and it is significantly more computationally efficient than the nonlinear CFD model. The slosh model is subsequently applied to roll plane model of a suspended tank vehicle to study the effect of dynamic liquid slosh on steady-turning roll stability limit of the vehicle under constant and variable axle load conditions. The results suggest that the roll moment arising from the dynamic fluid slosh yields considerably lower roll stability limit of the partly-filled tank vehicle compared to that predicted from the widely reported quasi-static fluid slosh model.

  11. Links between fluid circulation, temperature, and metamorphism in subducting slabs

    USGS Publications Warehouse

    Spinelli, G.A.; Wang, K.

    2009-01-01

    The location and timing of metamorphic reactions in subducting lithosph??re are influenced by thermal effects of fluid circulation in the ocean crust aquifer. Fluid circulation in subducting crust extracts heat from the Nankai subduction zone, causing the crust to pass through cooler metamorphic faci??s than if no fluid circulation occurs. This fluid circulation shifts the basalt-to-eclogite transition and the associated slab dehydration 14 km deeper (35 km farther landward) than would be predicted with no fluid flow. For most subduction zones, hydrothermal cooling of the subducting slab will delay eclogitization relative to estimates made without considering fluid circulation. Copyright 2009 by the American Geophysical Union.

  12. Analysis, approximation, and computation of a coupled solid/fluid temperature control problem

    NASA Technical Reports Server (NTRS)

    Gunzburger, Max D.; Lee, Hyung C.

    1993-01-01

    An optimization problem is formulated motivated by the desire to remove temperature peaks, i.e., 'hot spots', along the bounding surfaces of containers of fluid flows. The heat equation of the solid container is coupled to the energy equations for the fluid. Heat sources can be located in the solid body, the fluid, or both. Control is effected by adjustments to the temperature of the fluid at the inflow boundary. Both mathematical analyses and computational experiments are given.

  13. Solving the heat-flow problem with transient relativistic fluid dynamics

    NASA Astrophysics Data System (ADS)

    Denicol, G. S.; Niemi, H.; Bouras, I.; Molnár, E.; Xu, Z.; Rischke, D. H.; Greiner, C.

    2014-04-01

    Israel-Stewart theory is a causal, stable formulation of relativistic dissipative fluid dynamics. This theory has been shown to give a decent description of the dynamical behavior of a relativistic fluid in cases where shear stress becomes important. In principle, it should also be applicable to situations where heat flow becomes important. However, it has been shown that there are cases where Israel-Stewart theory cannot reproduce phenomena associated with heat flow. In this paper, we derive a relativistic dissipative fluid-dynamical theory from kinetic theory which provides a good description of all dissipative phenomena, including heat flow. We explicitly demonstrate this by comparing this theory with numerical solutions of the relativistic Boltzmann equation.

  14. Heat exchanger temperature response for duty-cycle transients in the NGNP/HTE.

    SciTech Connect

    Vilim, R. B.; Nuclear Engineering Division

    2009-03-12

    Control system studies were performed for the Next Generation Nuclear Plant (NGNP) interfaced to the High Temperature Electrolysis (HTE) plant. Temperature change and associated thermal stresses are important factors in determining plant lifetime. In the NGNP the design objective of a 40 year lifetime for the Intermediate Heat Exchanger (IHX) in particular is seen as a challenge. A control system was designed to minimize temperature changes in the IHX and more generally at all high-temperature locations in the plant for duty-cycle transients. In the NGNP this includes structures at the reactor outlet and at the inlet to the turbine. This problem was approached by identifying those high-level factors that determine temperature rates of change. First are the set of duty cycle transients over which the control engineer has little control but which none-the-less must be addressed. Second is the partitioning of the temperature response into a quasi-static component and a transient component. These two components are largely independent of each other and when addressed as such greater understanding of temperature change mechanisms and how to deal with them is achieved. Third is the manner in which energy and mass flow rates are managed. Generally one aims for a temperature distribution that minimizes spatial non-uniformity of thermal expansion in a component with time. This is can be achieved by maintaining a fixed spatial temperature distribution in a component during transients. A general rule of thumb for heat exchangers is to maintain flow rate proportional to thermal power. Additionally the product of instantaneous flow rate and heat capacity should be maintained the same on both sides of the heat exchanger. Fourth inherent mechanisms for stable behavior should not be compromised by active controllers that can introduce new feedback paths and potentially create under-damped response. Applications of these principles to the development of a plant control strategy for

  15. Rheologically stable, nontoxic, high-temperature, water-based drilling fluid

    SciTech Connect

    Elward-Berry, J.; Darby, J.B.

    1997-09-01

    An exceptionally stable, high-temperature, water-based drilling fluid has been developed based on a fundamental redesign of drilling fluid components and functions, while still using commercially available materials. Rheological stability was characterized by extensive Fann 50C low-shear-rate viscosity vs. temperature studies and supporting viscoelastic rheological data. The fluid has been used in offshore and land applications, at temperatures as high as 420 F and densities as high as 15.5 lbm/gal.

  16. Modeling of Transient Heat Pipe Operation

    NASA Technical Reports Server (NTRS)

    Colwell, G. T.; Hartley, J. G.

    1984-01-01

    The major goal of this project is to develop mathematical models of heat pipes which can be used to predict transient behavior under normal and adverse conditions. The models and solution techniques are to be formulated so that they can be incorporated into existing NASA structural design codes. The major parameters of interest are heat flux distribution, temperature distribution, working fluid pressure distribution, fluid and containment thermal and mechanical properties and geometry. Normal transient operation is taken to be operating conditions where the capillary structure remains fully wetted. Adverse transient operation occurs when drying, re-wetting, choking, non-continuum flow, thawing, freezing, etc., occur in the internal heat pipe working fluid.

  17. TEMP: a computer code to calculate fuel pin temperatures during a transient. [LMFBR

    SciTech Connect

    Bard, F E; Christensen, B Y; Gneiting, B C

    1980-04-01

    The computer code TEMP calculates fuel pin temperatures during a transient. It was developed to accommodate temperature calculations in any system of axi-symmetric concentric cylinders. When used to calculate fuel pin temperatures, the code will handle a fuel pin as simple as a solid cylinder or as complex as a central void surrounded by fuel that is broken into three regions by two circumferential cracks. Any fuel situation between these two extremes can be analyzed along with additional cladding, heat sink, coolant or capsule regions surrounding the fuel. The one-region version of the code accurately calculates the solution to two problems having closed-form solutions. The code uses an implicit method, an explicit method and a Crank-Nicolson (implicit-explicit) method.

  18. Code System for Transient and Steady-State Temperature Distribution in Multidimensional Systems.

    Energy Science and Technology Software Center (ESTSC)

    2005-10-24

    Version 01 TRUMP solves a general nonlinear parabolic partial differential equation describing flow in various kinds of potential fields, such as fields of temperature, pressure, or electricity and magnetism; simultaneously, it will solve two additional equations representing, in thermal problems, heat production by decomposition of two reactants having rate constants with a general Arrhenius temperature dependence. Steady‑state and transient flow in one, two, or three dimensions are considered in geometrical configurations having simple or complexmore » shapes and structures. Problem parameters may vary with spatial position, time, or primary dependent variables, temperature, pressure, or field strength. Initial conditions may vary with spatial position, and among the criteria that may be specified for ending a problem are upper and lower limits on the size of the primary dependent variable, upper limits on the problem time or on the number of time‑steps or on the computer time, and attainment of steady state.« less

  19. An anisotropic thermomechanical damage model for concrete at transient elevated temperatures.

    PubMed

    Baker, Graham; de Borst, René

    2005-11-15

    The behaviour of concrete at elevated temperatures is important for an assessment of integrity (strength and durability) of structures exposed to a high-temperature environment, in applications such as fire exposure, smelting plants and nuclear installations. In modelling terms, a coupled thermomechanical analysis represents a generalization of the computational mechanics of fracture and damage. Here, we develop a fully coupled anisotropic thermomechanical damage model for concrete under high stress and transient temperature, with emphasis on the adherence of the model to the laws of thermodynamics. Specific analytical results are given, deduced from thermodynamics, of a novel interpretation on specific heat, evolution of entropy and the identification of the complete anisotropic, thermomechanical damage surface. The model is also shown to be stable in a computational sense, and to satisfy the laws of thermodynamics. PMID:16243703

  20. A numerical study of the Kernel-conformation transformation for transient viscoelastic fluid flows

    NASA Astrophysics Data System (ADS)

    Martins, F. P.; Oishi, C. M.; Afonso, A. M.; Alves, M. A.

    2015-12-01

    This work presents a numerical application of a generic conformation tensor transformation for simulating highly elastic flows of non-Newtonian fluids typically observed in computational rheology. In the Kernel-conformation framework [14], the conformation tensor constitutive law for a viscoelastic fluid is transformed introducing a generic tensor transformation function. The numerical stability of the application of the Kernel-conformation for highly elastic flows is ultimately related with the specific kernel function used in the matrix transformation, but also to the existence of singularities introduced either by flow geometry or by the characteristics of the constitutive equation. In this work, we implement this methodology in a free-surface Marker-And-Cell discretization methodology implemented in a finite differences method. The main contributions of this work are two fold: on one hand, we demonstrate the accuracy of this Kernel-conformation formulation using a finite differences method and free surfaces; on the other hand, we assess the numerical efficiency of specific kernel functions at high-Weissenberg number flows. The numerical study considers different viscoelastic fluid flow problems, including the Poiseuille flow in a channel, the lid-driven cavity flow and the die-swell free surface flow. The numerical results demonstrate the adequacy of this methodology for high Weissenberg number flows using the Oldroyd-B model.

  1. Estimating transient climate response using consistent temperature reconstruction methods in models and observations

    NASA Astrophysics Data System (ADS)

    Richardson, M.; Cowtan, K.; Hawkins, E.; Stolpe, M.

    2015-12-01

    Observational temperature records such as HadCRUT4 typically have incomplete geographical coverage and blend air temperature over land with sea surface temperatures over ocean, in contrast to model output which is commonly reported as global air temperature. This complicates estimation of properties such as the transient climate response (TCR). Observation-based estimates of TCR have been made using energy-budget constraints applied to time series of historical radiative forcing and surface temperature changes, while model TCR is formally derived from simulations where CO2 increases at 1% per year. We perform a like-with-like comparison using three published energy-budget methods to derive modelled TCR from historical CMIP5 temperature series sampled in a manner consistent with HadCRUT4. Observation-based TCR estimates agree to within 0.12 K of the multi-model mean in each case and for 2 of the 3 energy-budget methods the observation-based TCR is higher than the multi-model mean. For one energy-budget method, using the HadCRUT4 blending method leads to a TCR underestimate of 0.3±0.1 K, relative to that estimated using global near-surface air temperatures.

  2. Predicting transient particle transport in enclosed environments with the combined computational fluid dynamics and Markov chain method.

    PubMed

    Chen, C; Lin, C-H; Long, Z; Chen, Q

    2014-02-01

    To quickly obtain information about airborne infectious disease transmission in enclosed environments is critical in reducing the infection risk to the occupants. This study developed a combined computational fluid dynamics (CFD) and Markov chain method for quickly predicting transient particle transport in enclosed environments. The method first calculated a transition probability matrix using CFD simulations. Next, the Markov chain technique was applied to calculate the transient particle concentration distributions. This investigation used three cases, particle transport in an isothermal clean room, an office with an underfloor air distribution system, and the first-class cabin of an MD-82 airliner, to validate the combined CFD and Markov chain method. The general trends of the particle concentrations vs. time predicted by the Markov chain method agreed with the CFD simulations for these cases. The proposed Markov chain method can provide faster-than-real-time information about particle transport in enclosed environments. Furthermore, for a fixed airflow field, when the source location is changed, the Markov chain method can be used to avoid recalculation of the particle transport equation and thus reduce computing costs. PMID:23789964

  3. Low temperature biodegradation of airport de-icing fluids.

    PubMed

    Revitt, D M; Worrall, P

    2003-01-01

    The biodegradabilities of glycol- and acetate-based aircraft de-icing fluids on airport surfaces have been investigated at three temperatures between 0 degrees C and 10 degrees C. The aqueous solubilities of these substances can result in high BOD loadings in runoff and pose serious toxicity problems in receiving waters. The measured surface biodegradation rates for de-icing products based on ethylene/diethylene glycol (Konsin), propylene glycol (Kilfrost) and potassium acetate (Clearway) at 4 degrees C were 0.082, 0.073 and 0.033 day(-1). The resulting reductions in the potential BOD loadings, of a single application of a typical mixture of these products, over a 5 day biodegradation period are predicted to be 32.9%, 30.2% and 21.4%, respectively at 8 degrees C, 4 degrees C and 1 degrees C. For consecutive daily applications, the comparable cumulative reductions over 5 days are 20.8%, 18.9% and 13.3%. The subsequent savings in the amount of treatment required for airport runoff prior to safe discharge to receiving waters are discussed and hence the relevance of surface biodegradation processes to the design of stormwater treatment systems involving the wash-off of biodegradable pollutants following retention on urban surfaces. PMID:14703144

  4. Analytical study of the liquid phase transient behavior of a high temperature heat pipe. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Roche, Gregory Lawrence

    1988-01-01

    The transient operation of the liquid phase of a high temperature heat pipe is studied. The study was conducted in support of advanced heat pipe applications that require reliable transport of high temperature drops and significant distances under a broad spectrum of operating conditions. The heat pipe configuration studied consists of a sealed cylindrical enclosure containing a capillary wick structure and sodium working fluid. The wick is an annular flow channel configuration formed between the enclosure interior wall and a concentric cylindrical tube of fine pore screen. The study approach is analytical through the solution of the governing equations. The energy equation is solved over the pipe wall and liquid region using the finite difference Peaceman-Rachford alternating direction implicit numerical method. The continuity and momentum equations are solved over the liquid region by the integral method. The energy equation and liquid dynamics equation are tightly coupled due to the phase change process at the liquid-vapor interface. A kinetic theory model is used to define the phase change process in terms of the temperature jump between the liquid-vapor surface and the bulk vapor. Extensive auxiliary relations, including sodium properties as functions of temperature, are used to close the analytical system. The solution procedure is implemented in a FORTRAN algorithm with some optimization features to take advantage of the IBM System/370 Model 3090 vectorization facility. The code was intended for coupling to a vapor phase algorithm so that the entire heat pipe problem could be solved. As a test of code capabilities, the vapor phase was approximated in a simple manner.

  5. Characterization of reservoir rocks and fluids by surface electromagnetic transient methods

    SciTech Connect

    Hoekstra, P.; Blohm, M.W. ); Stoyer, C.H. ); James, B.A. )

    1992-01-01

    The objectives of this research are to improve the interpretations of transient electromagnetic (TEM) measurements over two-dimensional subsurface structures. TEM is a surface electromagnetic method employed in fossil energy reservoir exploration and characterization. Electrical measurements find application in (i) assisting in fossil energy exploration mainly in areas where seismic methods yield inadequate data quality, such as volcanic covered terrain, permafrost areas, and the Rocky Mountain overthrust; (ii) mapping contacts between hydrocarbon and brines in shallow producing horizons, and (iii) in monitoring enhanced oil recovery processes which cause zones of lower resistivity. Accomplishments for this past year are presented for the following tasks: (1) site selection and acquisition of high density, 3-component TEM data set over test site; (2) finite element forward modeling; and (3) TEM 2-D subsurface imaging.

  6. Characterization of reservoir rocks and fluids by surface electromagnetic transient methods

    SciTech Connect

    Hoekstra, P.; Blohm, M.W.; Stoyer, C.H.; James, B.A.

    1992-07-17

    The objectives of this research were to improve the interpretations of transient electromagnetic (TEM) measurements over two-dimensional subsurface structures. TEM is a surface electromagnetic method employed in fossil energy reservoir exploration and characterization. Electrical measurements find application in (i) assisting in fossil energy exploration mainly in areas where seismic methods yield inadequate data quality, such as volcanic covered terrain, permafrost areas, and the Rocky Mountain Overthrust; (ii) mapping contacts between hydrocarbon and brines in shallow producing horizon, and (iii) in monitoring enhanced oil recovery processes which cause zones of lower resistivity. The work under this contract consisted of three tasks: (1) Selection of a test site and acquisition of a high density, 3-component data set over the test site; (2) development of finite element modeling algorithms for computing 3-D EM fields over 2-D EM fields over 2-D subsurface structures; and development of TEM 2-D subsurface imaging method. Accomplishments for this period are described.

  7. Cosmological thermodynamics with Hawking temperature on the apparent horizon and Unruh temperature of the fluid: Some interesting consequences

    NASA Astrophysics Data System (ADS)

    Saha, Subhajit

    2016-06-01

    Thermodynamics on the cosmological apparent horizon of a flat Friedmann-Lemaitre-Robertson-Walker metric has been investigated with Bekenstein entropy and Hawking temperature on the horizon, and Unruh temperature for the fluid inside the horizon. This temperature is experienced by a radial comoving observer infinitesimally close to the horizon due to the pressure exerted by the fluid bounded by the horizon. An expression for the entropy of the fluid has been obtained which is found to be proportional to the volume of the thermodynamic system which implies that the Unruh temperature of the fluid is inconsistent with the holographic principle. Further, we have been able to find an expression for the effective entropy of the system. Finally, assuming a barotropic equation of state p=wρ (w constant) for the fluid, it has been shown that the generalized second law holds good for a non-phantom w, while thermodynamic equilibrium is never possible for such a scenario.

  8. Local-heterogeneous responses and transient dynamics of cage breaking and formation in colloidal fluids

    NASA Astrophysics Data System (ADS)

    Nag, Preetom; Teramoto, Hiroshi; Li, Chun-Biu; Terdik, Joseph Z.; Scherer, Norbert F.; Komatsuzaki, Tamiki

    2014-09-01

    Quantifying the interactions in dense colloidal fluids requires a properly designed order parameter. We present a modified bond-orientational order parameter, bar{ψ }6, to avoid problems of the original definition of bond-orientational order parameter. The original bond-orientational order parameter can change discontinuously in time but our modified order parameter is free from the discontinuity and, thus, it is a suitable measure to quantify the dynamics of the bond-orientational ordering of the local surroundings. Here we analyze bar{ψ }6 in a dense driven monodisperse quasi-two-dimensional colloidal fluids where a single particle is optically trapped at the center. The perturbation by the trapped and driven particle alters the structure and dynamics of the neighboring particles. This perturbation disturbs the flow and causes spatial and temporal distortion of the bond-orientational configuration surrounding each particle. We investigate spatio-temporal behavior of bar{ψ }6 by a Wavelet transform that provides a time-frequency representation of the time series of bar{ψ }6. It is found that particles that have high power in frequencies corresponding to the inverse of the timescale of perturbation undergo distortions of their packing configurations that result in cage breaking and formation dynamics. To gain insight into the dynamic structure of cage breaking and formation of bond-orientational ordering, we compare the cage breaking and formation dynamics with the underlying dynamical structure identified by Lagrangian Coherent Structures (LCSs) estimated from the finite-time Lyapunov exponent (FTLE) field. The LCSs are moving separatrices that effectively divide the flow into distinct regions with different dynamical behavior. It is shown that the spatial distribution of the FTLE field and the power of particles in the wavelet transform have positive correlation, implying that LCSs provide a dynamic structure that dominates the dynamics of cage breaking and

  9. Temperature dependence of magnetic moments of nanoparticles and their dipole interaction in magnetic fluids

    NASA Astrophysics Data System (ADS)

    Lebedev, A. V.

    2015-01-01

    Magnetic susceptibility measurements were carried out for magnetite-based fluids over a wide temperature range. The fluids were stabilized with commonly used surfactants (fatty acids) and new surfactants (polypropylene glycol and tallow acids). The coefficients of temperature dependence of the particle magnetic moments were determined by fitting of the measured and calculated values of magnetic susceptibility. The influence of the inter-particle dipole-dipole interaction on the susceptibility was taken into account in the framework of A.O. Ivanov's model. The corrections for thermal expansion were determined by density measurements of the carrier fluid. The obtained values of temperature coefficients correlate to the solidification temperature of the fluid samples. For fluids with a low solidification temperature the value of the temperature coefficient of particle magnetization coincides with its value for bulk magnetite.

  10. Transient turbid water mass reduces temperature-induced coral bleaching and mortality in Barbados.

    PubMed

    Oxenford, Hazel A; Vallès, Henri

    2016-01-01

    Global warming is seen as one of the greatest threats to the world's coral reefs and, with the continued rise in sea surface temperature predicted into the future, there is a great need for further understanding of how to prevent and address the damaging impacts. This is particularly so for countries whose economies depend heavily on healthy reefs, such as those of the eastern Caribbean. Here, we compare the severity of bleaching and mortality for five dominant coral species at six representative reef sites in Barbados during the two most significant warm-water events ever recorded in the eastern Caribbean, i.e., 2005 and 2010, and describe prevailing island-scale sea water conditions during both events. In so doing, we demonstrate that coral bleaching and subsequent mortality were considerably lower in 2010 than in 2005 for all species, irrespective of site, even though the anomalously warm water temperature profiles were very similar between years. We also show that during the 2010 event, Barbados was engulfed by a transient dark green turbid water mass of riverine origin coming from South America. We suggest that reduced exposure to high solar radiation associated with this transient water mass was the primary contributing factor to the lower bleaching and mortality observed in all corals. We conclude that monitoring these episodic mesoscale oceanographic features might improve risk assessments of southeastern Caribbean reefs to warm-water events in the future. PMID:27326377

  11. Transient turbid water mass reduces temperature-induced coral bleaching and mortality in Barbados

    PubMed Central

    Vallès, Henri

    2016-01-01

    Global warming is seen as one of the greatest threats to the world’s coral reefs and, with the continued rise in sea surface temperature predicted into the future, there is a great need for further understanding of how to prevent and address the damaging impacts. This is particularly so for countries whose economies depend heavily on healthy reefs, such as those of the eastern Caribbean. Here, we compare the severity of bleaching and mortality for five dominant coral species at six representative reef sites in Barbados during the two most significant warm-water events ever recorded in the eastern Caribbean, i.e., 2005 and 2010, and describe prevailing island-scale sea water conditions during both events. In so doing, we demonstrate that coral bleaching and subsequent mortality were considerably lower in 2010 than in 2005 for all species, irrespective of site, even though the anomalously warm water temperature profiles were very similar between years. We also show that during the 2010 event, Barbados was engulfed by a transient dark green turbid water mass of riverine origin coming from South America. We suggest that reduced exposure to high solar radiation associated with this transient water mass was the primary contributing factor to the lower bleaching and mortality observed in all corals. We conclude that monitoring these episodic mesoscale oceanographic features might improve risk assessments of southeastern Caribbean reefs to warm-water events in the future. PMID:27326377

  12. High temperature creep of SiC densified using a transient liquid phase

    SciTech Connect

    Jou, Z.C.; Virkar, A.V. ); Cutler, R.A. )

    1991-09-01

    Silicon carbide-based ceramics can be rapidly densified above approximately 1850 {degree}C due to a transient liquid phase resulting from the reaction between alumina and aluminum oxycarbides. The resulting ceramics are fine-grained, dense, and exhibit high strength at room temperature. SiC hot pressed at 1875 {degree}C for 10 min in Ar was subjected to creep deformation in bending at elevated temperatures between 1500 and 1650 {degree}C in Ar. Creep was thermally activated with an activation energy of 743 kJ/mol. Creep rates at 1575 {degree}C were between 10{sup {minus}9}/s and 10{sup {minus}7}/s at an applied stress between 38 and 200 MPa, respectively, resulting in a stress exponent of {approx}1.7.

  13. Lifetime improvement of sheathed thermocouples for use in high-temperature and thermal transient operations

    SciTech Connect

    McCulloch, R.W.; Clift, J.H.

    1982-01-01

    Premature failure of small-diameter, magnesium-oxide-insulated sheathed thermocouples occurred when they were placed within nuclear fuel rod simulators (FRSs) to measure high temperatures and to follow severe thermal transients encountered during simulation of nuclear reactor accidents in Oak Ridge National Laboratory (ORNL) thermal-hydraulic test facilities. Investigation of thermally cycled thermocouples yielded three criteria for improvement of thermocouple lifetime: (1) reduction of oxygen impurities prior to and during their fabrication, (2) refinement of thermoelement grain size during their fabrication, and (3) elimination of prestrain prior to use above their recrystallization temperature. The first and third criteria were satisfied by improved techniques of thermocouple assembly and by a recovery anneal prior to thermocouple use.

  14. Transient Thermal Impedance Measurements on Low-Temperature-Sintered Nanoscale Silver Joints

    NASA Astrophysics Data System (ADS)

    Mei, Yunhui; Wang, Tao; Cao, Xiao; Chen, Gang; Lu, Guo-Quan; Chen, Xu

    2012-11-01

    A measurement system for thermal impedance ( Z th) was developed to evaluate the transient thermal performance of sintered nanoscale silver joints. Five different temperature profiles for low-temperature sintering were evaluated by Z th measurements of the joints. The thermal impedance of the sintered samples was altered by the different sintering conditions. Samples that underwent heating profiles with a separate drying stage offered lower thermal impedance than those sintered directly. Exerting pressure of more than 1 MPa during sintering insignificantly improved the thermal impedance. Besides, the impedance could be lowered by extending the holding time of the drying stage and applying pressure as low as 1 MPa during sintering. Characterization of microstructures of the sintered layers was performed by scanning electron microscopy (SEM). With more cracks present, the thermal impedance of the chip joints increased. The presence of cracks was possibly attributed to fast drying or the lack of a drying step.

  15. Temperature and voltage coupling to channel opening in transient receptor potential melastatin 8 (TRPM8).

    PubMed

    Raddatz, Natalia; Castillo, Juan P; Gonzalez, Carlos; Alvarez, Osvaldo; Latorre, Ramon

    2014-12-19

    Expressed in somatosensory neurons of the dorsal root and trigeminal ganglion, the transient receptor potential melastatin 8 (TRPM8) channel is a Ca(2+)-permeable cation channel activated by cold, voltage, phosphatidylinositol 4,5-bisphosphate, and menthol. Although TRPM8 channel gating has been characterized at the single channel and macroscopic current levels, there is currently no consensus regarding the extent to which temperature and voltage sensors couple to the conduction gate. In this study, we extended the range of voltages where TRPM8-induced ionic currents were measured and made careful measurements of the maximum open probability the channel can attain at different temperatures by means of fluctuation analysis. The first direct measurements of TRPM8 channel temperature-driven conformational rearrangements provided here suggest that temperature alone is able to open the channel and that the opening reaction is voltage-independent. Voltage is a partial activator of TRPM8 channels, because absolute open probability values measured with fully activated voltage sensors are less than 1, and they decrease as temperature rises. By unveiling the fast temperature-dependent deactivation process, we show that TRPM8 channel deactivation is well described by a double exponential time course. The fast and slow deactivation processes are temperature-dependent with enthalpy changes of 27.2 and 30.8 kcal mol(-1). The overall Q10 for the closing reaction is about 33. A three-tiered allosteric model containing four voltage sensors and four temperature sensors can account for the complex deactivation kinetics and coupling between voltage and temperature sensor activation and channel opening. PMID:25352597

  16. Temperature and Voltage Coupling to Channel Opening in Transient Receptor Potential Melastatin 8 (TRPM8)*♦

    PubMed Central

    Raddatz, Natalia; Castillo, Juan P.; Gonzalez, Carlos; Alvarez, Osvaldo; Latorre, Ramon

    2014-01-01

    Expressed in somatosensory neurons of the dorsal root and trigeminal ganglion, the transient receptor potential melastatin 8 (TRPM8) channel is a Ca2+-permeable cation channel activated by cold, voltage, phosphatidylinositol 4,5-bisphosphate, and menthol. Although TRPM8 channel gating has been characterized at the single channel and macroscopic current levels, there is currently no consensus regarding the extent to which temperature and voltage sensors couple to the conduction gate. In this study, we extended the range of voltages where TRPM8-induced ionic currents were measured and made careful measurements of the maximum open probability the channel can attain at different temperatures by means of fluctuation analysis. The first direct measurements of TRPM8 channel temperature-driven conformational rearrangements provided here suggest that temperature alone is able to open the channel and that the opening reaction is voltage-independent. Voltage is a partial activator of TRPM8 channels, because absolute open probability values measured with fully activated voltage sensors are less than 1, and they decrease as temperature rises. By unveiling the fast temperature-dependent deactivation process, we show that TRPM8 channel deactivation is well described by a double exponential time course. The fast and slow deactivation processes are temperature-dependent with enthalpy changes of 27.2 and 30.8 kcal mol−1. The overall Q10 for the closing reaction is about 33. A three-tiered allosteric model containing four voltage sensors and four temperature sensors can account for the complex deactivation kinetics and coupling between voltage and temperature sensor activation and channel opening. PMID:25352597

  17. The role of grain boundaries and transient porosity in rocks as fluid pathways for reaction front propagation

    NASA Astrophysics Data System (ADS)

    Jonas, Laura; John, Timm; King, Helen E.; Geisler, Thorsten; Putnis, Andrew

    2014-01-01

    The pseudomorphic replacement of Carrara marble by calcium phosphates was used as a model system in order to study the influence of different fluid pathways for reaction front propagation induced by fluid-rock interaction. In this model, grain boundaries present in the rock as well as the transient porosity structures developing throughout the replacement reaction enable the reaction front to progress further into the rock as well as to the center of each single grain until transformation is complete. Hydrothermal treatment of the marble using phosphate bearing solutions led to the formation of hydroxylapatite and β-TCP; the formation of the latter phase was probably promoted by the presence of ∼0.6 wt.% Mg in the parent carbonate phase. Completely transformed single grains show a distinctive zoning, both in composition and texture. Whereas areas next to the grain boundary consist of nearly pure hydroxylapatite and show a coarse porosity, areas close to the center of the single grains show a high amount of β-TCP and a very fine porous microstructure. If fluorine was added as an additional solution component, up to 3 wt.% of F were incorporated into the product apatite and the formation of β-TCP was avoided. The use of the isotope 18O as a chronometer for the replacement reaction makes it possible to reconstruct the chronological development of the calcium phosphate reaction front. Raman analysis revealed that the incorporation of 18O in the PO4 tetrahedron of hydroxylapatite results in the development of distinct profiles in the calcium phosphate reaction front perpendicular to the grain boundaries of the marble. Through the use of the 18O chronometer, it is possible to estimate and compare the time effectiveness of the different fluid pathways in this model system. The results demonstrate that the grain boundaries are an effective pathway enabling the fluid to penetrate the rock more than one order of magnitude faster compared to the newly developing channel

  18. Temperature-driven transient charge and heat currents in nanoscale conductors

    NASA Astrophysics Data System (ADS)

    Eich, F. G.; Di Ventra, M.; Vignale, G.

    2016-04-01

    We analyze the short-time behavior of the heat and charge currents through nanoscale conductors exposed to a temperature gradient. To this end, we employ Luttinger's thermomechanical potential to simulate a sudden change of temperature at one end of the conductor. We find that the direction of the charge current through an impurity is initially opposite to the direction of the charge current in the steady-state limit. Furthermore, we investigate the transient propagation of energy and particle density driven by a temperature variation through a conducting nanowire. Interestingly, we find that the velocity of the wavefronts of, both, the particle and the energy wave have the same constant value, insensitive to changes in the average electronic density. In the steady-state regime, we find that, at low temperatures, the local temperature and potential, as measured by a floating probe lead, exhibit characteristic oscillations due to quantum interference, with a periodicity that corresponds to half the Fermi wavelength of the electrons.

  19. Transient monoplegia and paraesthesia after an epidural blood patch for a spinal cerebrospinal fluid leak.

    PubMed

    Cheung, Alvin Ho-Kwan; Li, Lai-Fung; So, Vincent Ching; Leung, May Ka-Mei; Lui, Wai-Man

    2015-09-01

    We describe the very rare complication of new onset complete paralysis and numbness of one limb after an epidural blood patch in a 36-year-old woman. Intracranial hypotension resulting from a spinal cerebrospinal fluid fistula may be treated by epidural injection of autologous blood that is, a blood patch. This is usually a safe and effective procedure. The woman's muscle strength of hip flexion, extension, ankle dorsiflexion and plantarflexion decreased from 5/5 to 0/5 following the procedure. After symptom onset, an MRI of her spine showed no compressive or ischaemic lesions amenable to urgent intervention. The cause of neurological deficit was at that time unknown and steroids were administered. Her symptoms persisted for about 2 days and gradually improved. In this paper, the management plan and the course of this rare and alarming complication is reported. PMID:25986178

  20. Intestinal temperature does not reflect rectal temperature during prolonged, intense running with cold fluid ingestion.

    PubMed

    Savoie, Félix A; Dion, Tommy; Asselin, Audrey; Gariepy, Carolanne; Boucher, Pierre M; Berrigan, Félix; Goulet, Eric D B

    2015-02-01

    It is generally assumed that intestinal temperature (Tint), as measured with a telemetric pill, agrees relatively well with rectal temperature (Trec) during exercise. However, whether Tint reflects Trec during prolonged, intense and continuous exercise when cold fluids are consumed is unknown. Therefore, we compared Trec and Tint during a half-marathon during which cold water was ingested to prevent bodyweight (BW) losses >2%. Nine endurance athletes (age 30  ±  5 years) underwent a 21.1 km running time-trial (TT) in the heat (~30 °C and 44% RH) while BW losses were maintained to ~1% with continuous cold (4 °C) water provision. Tint and Trec were monitored throughout the TT. Hypohydration level, TT time and fluid intake were 1.2  ±  0.4% BW, 93.2  ±  9.9 min and 2143  ±  264 ml, respectively. Trec was systematically higher than Tint by 0.25 °C (95% CI: 0.14-0.37 °C). Tint and Trec showed an excellent relative (r = 0.90, p < 0.01), but poor absolute agreement as reflected by a 95% limit of agreement of ±1.07 °C and a standard error of measurement of ±0.39 °C. In conclusion, Tint does not mirror Trec during prolonged, intense running with cold fluid ingestion and, therefore, these measures should not be used interchangeably under this scenario. PMID:25582636

  1. Chemical reactions accompanying fluid flow through granite held in a temperature gradient

    USGS Publications Warehouse

    Moore, Diane E.; Morrow, C.A.; Byerlee, J.D.

    1983-01-01

    Distilled water was passed at a low rate down a temperature gradient through cylinders of Barre and Westerly Granite. Temperatures ranged from 80-100??C at the outer edges of the cylinders to 250-300??C in central, drilled holes which housed the heating coils. The measured permeabilities of the granite cylinders decreased by as much as two orders of magnitude in experiments of 1-3 weeks' duration. The amount of permeability decrease varied directly with temperature and inversely with the rate of fluid flow. The compositions of the fluids discharged from the granites were functions of temperature and flow rate as well as mineral composition, with dissolved silica concentrations showing trends different from those of the other analyzed species. Fluids from experiments run at higher temperatures but at much lower initial rates of fluid flow had higher concentrations of most ions but substantially lower dissolved silica contents. In contrast, an increase in temperature at similar rates of fluid flow resulted in higher silica concentrations. In the experiments, the distilled water acquired enough dissolved materials at high temperatures to become supersaturated with respect to several minerals at the low-temperature edges of the cylinders. Some of this material, particularly silica, was deposited along grain boundaries and microfractures, causing the observed permeability decreases. The very low rates of fluid flow in some high-temperature experiments significantly increased the rates of SiO2 precipitation and reduced dissolved silica concentrations relative to other species in the discharged fluids. ?? 1983.

  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. Prediction of transient temperatures for an air-cooled rotating disc

    NASA Astrophysics Data System (ADS)

    Long, C. A.; Owen, J. M.

    1985-09-01

    The numerical solution of Fourier's conduction equation is used to compute the transient temperature distribution in a rotating disc. The convective boundary conditions for the disc surfaces are based on simple formulae obtained from the solutions of the boundary-layer equations, and the computed surface temperatures are compared with measurements made on a rotating-disc rig. Free-disc tests, at rotational Reynolds numbers up to Re sub phi = 2.5 x 10(6), are used to provide a datum from which to judge the numerical method. Although the numerical solution tends to overestimate the cooling rate of the heated free disc at high Reynolds numbers, the agreement between computed and measured temperatures is considered reasonable. Rotating-cavity tests, in which a heated disc is cooled by a radial outflow of air, are used to examine the suitability of the simple convective boundary conditions. As the computed temperatures show reasonable agreement with the measured values, it is suggested that the proposed formulae for convection in a rotating cavity might be useful for design purposes.

  4. Temperature-dependent transformation thermotics for unsteady states: Switchable concentrator for transient heat flow

    NASA Astrophysics Data System (ADS)

    Li, Ying; Shen, Xiangying; Huang, Jiping; Ni, Yushan

    2016-04-01

    For manipulating heat flow efficiently, recently we established a theory of temperature-dependent transformation thermotics which holds for steady-state cases. Here, we develop the theory to unsteady-state cases by considering the generalized Fourier's law for transient thermal conduction. As a result, we are allowed to propose a new class of intelligent thermal metamaterial - switchable concentrator, which is made of inhomogeneous anisotropic materials. When environmental temperature is below or above a critical value, the concentrator is automatically switched on, namely, it helps to focus heat flux in a specific region. However, the focusing does not affect the distribution pattern of temperature outside the concentrator. We also perform finite-element simulations to confirm the switching effect according to the effective medium theory by assembling homogeneous isotropic materials, which bring more convenience for experimental fabrication than inhomogeneous anisotropic materials. This work may help to figure out new intelligent thermal devices, which provide more flexibility in controlling heat flow, and it may also be useful in other fields that are sensitive to temperature gradient, such as the Seebeck effect.

  5. Transient increase of ATP as a response to temperature up-shift in Escherichia coli

    PubMed Central

    Soini, Jaakko; Falschlehner, Christina; Mayer, Christina; Böhm, Daniela; Weinel, Stefan; Panula, Johanna; Vasala, Antti; Neubauer, Peter

    2005-01-01

    Background Escherichia coli induces the heat shock response to a temperature up-shift which is connected to the synthesis of a characteristic set of proteins, including ATP dependent chaperones and proteases. Therefore the balance of the nucleotide pool is important for the adaptation and continuous function of the cell. Whereas it has been observed in eukaryotic cells, that the ATP level immediately decreased after the temperature shift, no data are available for E. coli about the adenosine nucleotide levels during the narrow time range of minutes after a temperature up-shift. Results The current study shows that a temperature up-shift is followed by a very fast significant transient increase of the cellular ATP concentration within the first minutes. This increase is connected to a longer lasting elevation of the cellular respiration and glucose uptake. Also the mRNA level of typical heat shock genes increases within only one minute after the heat-shock. Conclusion The presented data prove the very fast response of E. coli to a heat-shock and that the initial response includes the increase of the ATP pool which is important to fulfil the need of the cell for new syntheses, as well as for the function of chaperones and proteases. PMID:15804347

  6. Fluid transients in pipes. Estimation of maximum pressures and forces in steam lines

    NASA Astrophysics Data System (ADS)

    1986-09-01

    Available as part of the ESDU Sub-series on Fluid Mechanics (Internal Flow), this document gives a graphical method for estimating the time-dependent pressure changes and piping forces that follow from a rapid value closure in a one-pipe system of constant cross-section carrying superheated steam. The method also assumes a frictionless flow and ignores wave steepening effects. A computer program listing in FORTRAN is also included that applies to any gas that obeys the perfect gas law, and takes into account the effects of both wall friction and wave steepening. In that case sections of the pipeline can have different cross-sectional areas and that can be used to treat a pipeline with branched ends. Worked examples are included for both methods and in the case of the computer program show specimen print-out of the input data, and of the output which includes the time variation of pressure, velocity and density at three points in the pipeline chosen by the user together with values of maximum and minimum pressure at 25 points (a value that is also open to choice by the user). The example is run for a valve with a linear variation of area with time, and for one with a nonlinear characteristic.

  7. Transient studies of low temperature catalysts for methane conversion. Final report, [September 1992--March 1996

    SciTech Connect

    Wolf, E.E.

    1996-09-30

    The objective of this project is to use transient techniques to study gas surface interactions during the oxidative conversion of methane. Two groups of catalysts were studied: a double oxide of vanadium and phosphate or VPO, and double oxides of Ni, Co and Rh and lanthana. The objective of the studies involving the VPO catalyst was to understand gas-surface interactions leading to the formation of formaldehyde. In the second group of catalysts, involving metallo-oxides, the main objective was to study the gas-surface interactions that determine the selectivity to C{sub 2} hydrocarbons or synthesis gas. Transient techniques were used to study the methane-surface interactions and the role of lattice oxygen. The selection of the double oxides was made on the hypothesis that the metal oxide would provide an increase interaction with methane whereas the phosphate or lanthanide would provide the sites for oxygen adsorption. The hypothesis behind this selection of catalysts was that increasing the methane interaction with the catalysts would lower the reaction temperature and thus increase the selectivity to the desired products over the total oxidation reaction. In both groups of catalysts the role of Li as a modifier of the selectivity was also studied in detail.

  8. Development and Transient Analysis of a Helical-coil Steam Generator for High Temperature Reactors

    SciTech Connect

    Nathan V. Hoffer; Nolan A. Anderson; Piyush Sabharwall

    2011-08-01

    A high temperature gas-cooled reactor (HTGR) is under development by the Next Generation Nuclear Plant (NGNP) Project at the Idaho National Laboratory (INL). Its design emphasizes electrical power production which may potentially be coupled with process heat for hydrogen production and other industrial applications. NGNP is considering a helical-coil steam generator for the primary heat transport loop heat exchanger based on its increased heat transfer and compactness when compared to other steam generators. The safety and reliability of the helical-coil steam generator is currently under evaluation as part of the development of NGNP. Transients, such as loss of coolant accidents (LOCA), are of interest in evaluating the safety of steam generators. In this study, a complete steam generator inlet pipe break (double ended pipe break) LOCA was simulated by an exponential loss of primary side pressure. For this analysis, a model of the helical-coil steam generator was developed using RELAP5-3D, an INL inhouse systems analysis code. The steam generator model behaved normally during the transient simulating the complete steam generator inlet pipe break LOCA. Further analysis is required to comprehensively evaluate the safety and reliability of the helical-coil steam generator design in the NGNP setting.

  9. Fluid Pressure and Temperature Response at the Nankai Trough Megasplay Fault: Initial Results of the SmartPlug Borehole Observatory

    NASA Astrophysics Data System (ADS)

    Hammerschmidt, S.; Kopf, A.; Expedition 332 Scientists, T.

    2011-12-01

    The SmartPlug is the first borehole observatory in the IODP Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE). It was installed at Site C0010 where it penetrates one of the shallow branches of the Megasplay fault to obtain pressure and temperature data from the fault and from a hydrostatic reference section. Here, a 15 months-lasting pore pressure and temperature record collected by the SmartPlug was evaluated. The main objective was to clarify the origin of transients in the data and its possible relationship to natural processes such as earthquakes, tectonic deformation or splay fault activity, as well as storms or low-pressure weather systems. After pressure and temperature data were processed properly, comparisons were made using seismic data from the Japanese F-Net and Hi-Net, theoretical travel time calculations provided by the USGS as well as earthquake lists from the ISC. Additionally, meteorological data provided by the JMA and the U.S. COAPS as well as theoretical travel time calculations for tsunamis from the U.S. NGDC were used. It can be shown that pulse-like pressure transients are related to regional/teleseismic earthquakes, originating mainly from the "Pacific Ring of Fire", from various depths and with diverse focal mechanisms. Approaching seismic waves of at least one regional earthquake led to a significant drop in the formation pressure, which is interpreted as a seismic wave-induced increase in permeability. The arrival of Rayleigh waves caused amplification of the borehole pressure, probably due to induced fluid flow. Tremor-like pressure transients are interpreted to be microseism, which is, based on pressure transient characteristics, triggered by storms or low-pressure weather systems on the open ocean. Approaching tsunamis look similar but caused longer period oscillations in the pressure record. Mainly in the seafloor pressure data distinct peaks are visible, some of which look similar to distinct peaks in the temperature data

  10. 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.

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

    SciTech Connect

    Kenyon, P.M.

    1993-12-01

    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.

  12. Cutting tool temperatures in contour turning: Transient analysis and experimental verification

    SciTech Connect

    Stephenson, D.A.; Jen, T.C.; Lavine, A.S.

    1995-12-31

    This paper describes a model for predicting cutting tool temperatures under transient conditions. It is applicable to processes such as contour turning, in which the cutting speed, feed rate, and depth of cut may vary continuously with time. The model is intended for use in process development and trouble shooting. Therefore, emphasis is given in the model development to enable rapid computation and to avoid the need to specify parameters such as thermal contact resistances and convection coefficients which are not known in practice. Experiments were conducted to validate the predictive model. The model predictions with two different boundary conditions bound the experimental results. An example is presented which shows the utility of the model for process planning.

  13. Impact of combined transient plasma/heat loads on tungsten performance below and above recrystallization temperature

    NASA Astrophysics Data System (ADS)

    Loewenhoff, Th.; Bardin, S.; Greuner, H.; Linke, J.; Maier, H.; Morgan, T. W.; Pintsuk, G.; Pitts, R. A.; Riccardi, B.; De Temmerman, G.

    2015-11-01

    The influence of recrystallization on thermal shock resistance has been identified as an issue that may influence the long term performance of ITER tungsten (W) divertor components. To investigate this issue a unique series of experiments has been performed on ITER divertor W monoblock mock-ups in three EU high heat flux facilities: GLADIS (neutral beam), JUDITH 2 (electron beam) and Magnum-PSI (plasma beam). To simulate ITER mitigated edge localised modes, heat fluxes between 0.11 and 0.6 GW m-2 were applied for Δt  <  1 ms. Two different base temperatures, Tbase  =  1200 °C and 1500 °C, were chosen on which ~18 000/100 000 transient events were superimposed representing several full ITER burning plasma discharges in terms of number of transients and particle fluence. An increase in roughening for both e-beam and plasma loaded surfaces was observed when loading during or after recrystallization and when loading at higher temperature. However, regarding the formation of cracks and microstructural modifications the response was different for e-beam and plasma loaded surfaces. The samples loaded in Magnum-PSI did not crack nor show any sign of recrystallization, even at Tbase  =  1500 °C. This could be a dynamic hydrogen flux effect, because pre-loading of samples with hydrogen neutrals (GLADIS) or without hydrogen (e-beam JUDITH 2) did not yield this result. These results show clearly that the loading method used when investigating and qualifying the thermal shock performance of materials for ITER and future fusion reactors can play an important role. This should be properly accounted for and in fact should be the subject of further R&D.

  14. Transient temperature distributions in simple conducting bodies steadily heated through a laminar boundary layer

    NASA Technical Reports Server (NTRS)

    Parker, Hermon M

    1953-01-01

    An analysis is made of the transient heat-conduction effects in three simple semi-infinite bodies: the flat insulated plate, the conical shell, and the slender solid cone. The bodies are assumed to have constant initial temperatures and, at zero time, to begin to move at a constant speed and zero angle of attack through a homogeneous atmosphere. The heat input is taken as that through a laminar boundary layer. Radiation heat transfer and transverse temperature gradients are assumed to be zero. The appropriate heat-conduction equations are solved by an iteration method, the zeroeth-order terms describing the situation in the limit of small time. The method is presented and the solutions are calculated to three orders which are sufficient to give reasonably accurate results when the forward edge has attained one-half the total temperature rise (nose half-rise time). Flight Mach number and air properties occur as parameters in the result. Approximate expressions for the extent of the conduction region and nose half-rise times as functions of the parameters of the problem are presented. (author)

  15. Effects of transient temperature increases on odor production from thermophilic anaerobic digestion.

    PubMed

    Iranpour, R; Alatriste-Mondragon, F; Cox, H H J; Haug, R T

    2005-01-01

    The City of Los Angeles, Bureau of Sanitation, has implemented thermophilic anaerobic sludge digestion at the Hyperion and Terminal Island Treatment Plants (HTP and TITP). A two-stage continuous-batch process was established at HTP, while a single-stage sequencing batch process was established at TITP. This was to evaluate compliance with the Class A pathogen reduction requirements of U.S. EPA 40 CFR Part 503. A rapid increase of the digester temperature at TITP from 57.5 to 65.5 degrees C caused an increase of the volatile fatty acid to alkalinity ratio, a decline in digester performance, and an elevated production of methyl mercaptan and hydrogen sulfide. A rapid increase of the digester temperature at HTP from 54 to 58 degrees C caused an elevated production of methyl mercaptan, but the effect on the volatile fatty acid to alkalinity ratio and digester performance was insignificant. It is likely that these effects observed at TITP and HTP were transient responses to rapid changes in temperature. PMID:16180433

  16. Sound velocity dispersion in room temperature ionic liquids studied using the transient grating method.

    PubMed

    Fukuda, M; Terazima, M; Kimura, Y

    2008-03-21

    Sound velocity is determined by the transient grating method in a range from 10(6) to 10(10) Hz in three room temperature ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, and N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide. In all room temperature ionic liquids studied, the sound velocity increased with increasing frequency. The cause of this change is posited to be structural relaxation in the room temperature ionic liquids. Frequency dependence of the sound velocity is not reproduced by a simple Debye relaxation model. The sound velocity dispersion relation in 1-butyl-3-methylimidazolium hexafluorophosphate matches a Cole-Davidson function with parameters determined by a dielectric relaxation [C. Daguenet et al., J. Phys. Chem. B 110, 12682 (2006)], indicating that structural and reorientational relaxations are strongly coupled. Conversely, the sound velocity dispersions of the other two ionic liquids measured do not match those measured for dielectric relaxation, implying that structural relaxation is much faster than the reorientational relaxation. This difference is discussed in relation to the motilities of anions and cations. PMID:18361592

  17. A numerical comparison with an exact solution for the transient response of a cylinder immersed in a fluid. [computer simulated underwater tests to determine transient response of a submerged cylindrical shell

    NASA Technical Reports Server (NTRS)

    Giltrud, M. E.; Lucas, D. S.

    1979-01-01

    The transient response of an elastic cylindrical shell immersed in an acoustic media that is engulfed by a plane wave is determined numerically. The method applies to the USA-STAGS code which utilizes the finite element method for the structural analysis and the doubly asymptotic approximation for the fluid-structure interaction. The calculations are compared to an exact analysis for two separate loading cases: a plane step wave and an exponentially decaying plane wave.

  18. Analytical solution of the transient temperature profile in gain medium of passively Q-switched microchip laser.

    PubMed

    Han, Xiahui; Li, Jianlang

    2014-11-01

    The transient temperature evolution in the gain medium of a continuous wave (CW) end-pumped passively Q-switched microchip (PQSM) laser is analyzed. By approximating the time-dependent population inversion density as a sawtooth function of time and treating the time-dependent pump absorption of a CW end-pumped PQSM laser as the superposition of an infinite series of short pumping pulses, the analytical expressions of transient temperature evolution and distribution in the gain medium for four- and three-level laser systems, respectively, are given. These analytical solutions are applied to evaluate the transient temperature evolution and distribution in the gain medium of CW end-pumped PQSM Nd:YAG and Yb:YAG lasers. PMID:25402922

  19. An estimate of the impact of transient luminous events on the atmospheric temperature

    NASA Astrophysics Data System (ADS)

    Arnone, E.; Berg, P.; Arnold, N. F.; Christiansen, B.; Thejll, P.

    2008-09-01

    We present an order of magnitude estimate of the impact of sprites and other transient luminous events (TLEs) on the atmospheric temperature via ozone changes. To address the effects of expected TLE-ozone changes of at most a few percent, we first study the linearity of the radiatively driven response of a stratosphere-mesosphere model and of a general circulation model (GCM) to a range of uniform climatological ozone perturbations. The study is limited to Northern Hemisphere winter conditions, when planetary wave activity is high and the non linear stratosphere-troposphere coupling can be strong. Throughout most of the middle atmosphere of both models, the radiatively driven temperature response to uniform 5% to 20% ozone perturbations shows a close-to linear relationship with the magnitude of the perturbation. A mid-latitude stratopause ozone perturbation is then imposed as an idealised experiment that mimics local temperature gradients introduced by the latitudinal dependence of TLEs. An unrealistically high 20% magnitude is adopted for the regional ozone perturbation to obtain statistical significance in the model response. The local linearity of the radiatively driven response is used to infer a first order estimate of TLE-induced temperature changes of the order of 0.015 K under typical conditions, and less than a peak temperature change of 0.3 K at 60 70 km height in coincidence of extraordinarily active TLE-producing thunderstorms before horizontal mixing quickly occurs. In the latter case, dedicated mesoscale modelling is needed to study the relevance of regional non linear processes which are expected to impact these radiatively driven responses.

  20. Fluid source and pressure temperature conditions of high-salinity fluids in syn-tectonic veins from the Northeastern Apuan Alps (Northern Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Montomoli, Chiara; Ruggieri, Giovanni; Carosi, Rodolfo; Dini, Andrea; Genovesi, Marianna

    Structural studies on syn-tectonic veins cropping out in the northeastern sector of the Apuan Alps metamorphic complex (Northern Apennines, Italy) revealed two sets of veins: (1) type A fibrous veins within the “Scisti sericitici Formation”, related to a late-D1 tectonic phase; (2) B-veins, within the “Diaspri Formation” that developed between late-D1 and D2 tectonic phases. The mineralogy of the A (quartz, chlorite, hematite with minor amounts of apatite, allanite-(Ce), thorite and synchysite) and B-veins (quartz only) reflects the mineralogical composition of the host-rocks: quartz, chlorite, white mica and accessory minerals (apatite, zircon, titanite) occur in the “Scisti sericitici Formation”, while quartz is the main phase in the “Diaspri Formation”. The study of fluid inclusions trapped in quartz crystals of the syn-tectonic veins shows that the inclusions are always oversaturated in NaCl at room temperature and their salinities range from 29.5 to 37 wt.% NaCl equiv. The isochore of the earliest trapped fluid inclusions (type IA; primary inclusions in fiber quartz of A veins), coupled with mineralogical geothermometric data, constrains the pressure-temperature conditions to around 325-300 MPa and 370-380 °C during the late-D1 phase. Subsequent trapping of inclusion types IIA, IIB, IIIA, IIIB and VB in the two vein sets probably occurred during a pressure-temperature decrease (down to 220-245 MPa and 260-270 °C) at a lithostatic thermal gradient of 30 °C/km. Type IVB inclusions, on the other hand, were probably trapped at lower pressure (between lithostatic and hydrostatic conditions) during a transient pressure drop resulting from fault-valve action. SEM/EDS analyses on salts precipitated within opened inclusions confirmed the NaCl-rich compositions of the trapped fluids and also revealed the presence of minor amounts of Ca, K and Mn in the salts. A fluid circulation model, based on mineralogical and fluid inclusion data, was proposed for

  1. Transient fluid-structure interaction of elongated bodies by finite-element method using elliptical and spheroidal absorbing boundaries.

    PubMed

    Bhattacharyya, S K; Premkumar, R

    2003-12-01

    In a domain method of solution of exterior scalar wave equation, the radiation condition needs to be imposed on a truncation boundary of the modeling domain. The Bayliss, Gunzberger, and Turkel (BGT) boundary dampers, which require a circular cylindrical and spherical truncation boundaries in two-(2D) and three-(3D)-dimensional problems, respectively, have been particularly successful in the analysis of scattering and radiation problems. However, for an elongated body, elliptical (2D) or spheroidal (3D) truncation boundaries have potential to reduce the size of modeling domain and hence computational effort. For harmonic problems, such extensions of the first- and second-order BGT dampers are available in the literature. In this paper, BGT dampers in both elliptical and spheroidal coordinate systems have been developed for transient problems involving acoustic radiation as well as fluid-structure interaction and implemented in the context of finite-element method based upon unsymmetric pressure-displacement formulation. Applications to elongated radiators and shells are reported using several numerical examples with excellent comparisons. It is demonstrated that significant computational economy can be achieved for elongated bodies with the use of these dampers. PMID:14714787

  2. Transient fluid-structure interaction of elongated bodies by finite-element method using elliptical and spheroidal absorbing boundaries

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S. K.; Premkumar, R.

    2003-12-01

    In a domain method of solution of exterior scalar wave equation, the radiation condition needs to be imposed on a truncation boundary of the modeling domain. The Bayliss, Gunzberger, and Turkel (BGT) boundary dampers, which require a circular cylindrical and spherical truncation boundaries in two-(2D) and three-(3D)-dimensional problems, respectively, have been particularly successful in the analysis of scattering and radiation problems. However, for an elongated body, elliptical (2D) or spheroidal (3D) truncation boundaries have potential to reduce the size of modeling domain and hence computational effort. For harmonic problems, such extensions of the first- and second-order BGT dampers are available in the literature. In this paper, BGT dampers in both elliptical and spheroidal coordinate systems have been developed for transient problems involving acoustic radiation as well as fluid-structure interaction and implemented in the context of finite-element method based upon unsymmetric pressure-displacement formulation. Applications to elongated radiators and shells are reported using several numerical examples with excellent comparisons. It is demonstrated that significant computational economy can be achieved for elongated bodies with the use of these dampers.

  3. Transient liquid phase bonding as a joining technique for high-temperature power electronics

    NASA Astrophysics Data System (ADS)

    Bosco, Nicholas Seth

    Fundamental aspects of transient liquid phase (TLP) bonding in the Cu-Sn system have been studied, with the objective of assessing the utility of the bonding technique in joining high-temperature SiC devices to direct bond copper (DBC) substrates in power electronic packages. This technique can be implemented at relatively low temperatures (in comparison to the melting point of Cu), yet provide bonds that have composition and properties that are similar to those of Cu. The bonding parameters of time, temperature, and interlayer thickness were probed. Additionally, two methods for the introduction of the interlayer were used: one based on the use of foils and the other based on electron beam deposition. The resulting microstructures were characterized using scanning electron microscopy and energy dispersive X-ray analysis. Microstructures consisting of the phases Cu6Sn5, Cu3Sn, Cu 41Sn11, and (Cu) were produced. The time required to form a bond with the targeted microstructure, notably that of (Cu), was found to be dominated by the consumption of intermediate phases, as dictated by diffusion, and thus scaled quadratically with initial interlayer thickness. Two types of bonding defects were obtained: one due to surface contamination and the other caused by the consumption of Sn through the formation of the Cu 6Sn5 intermetallic in the solid state during heating. The successful production of samples devoid of such defects was via electron beam deposition of the interlayer material, with sufficient thickness to ensure ample material for the formation of the transient liquid phase following solid state intermetallic formation. The mechanical properties of these bonds were measured and compared with those made with Sn foil. The toughness of the bonds in samples where the Sn interlayer was introduced by electron beam deposition was greater than that of samples that used an interlayer of Sn foil. The difference was attributed to the higher level of porosity and defects in

  4. 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.

  5. Time-resolved nature of exhaust gas emissions and piston wall temperature under transient operation in a small diesel engine

    SciTech Connect

    Reksowardojo, I.K.; Ogawa, Hideyuki; Miyamoto, Noboru; Enomoto, Yoshiteru; Kitamura, Toru

    1996-09-01

    Diesel combustion and exhaust gas emissions under transient operation (when fuel amounts abruptly increased) were investigated under a wide range of operating conditions with a newly developed gas sampling system. The relation between gas emissions and piston wall temperatures was also investigated. The results indicated that after the start of acceleration NOx, THC and smoke showed transient behaviors before reaching the steady state condition. Of the three gases, THC was most affected by piston wall temperature; its concentration decreased as the wall temperature increased throughout the acceleration except immediately after the start of acceleration. The number of cycles, at which gas concentrations reach the steady-state value after the start of acceleration, were about 1.2 times the cycle constant of the piston wall temperature for THC, and 2.3 times for smoke.

  6. Effect of horizontal heat and fluid flow on the vertical temperature distribution in a semiconfining layer

    USGS Publications Warehouse

    Lu, N.; Ge, S.

    1996-01-01

    By including the constant flow of heat and fluid in the horizontal direction, we develop an analytical solution for the vertical temperature distribution within the semiconfining layer of a typical aquifer system. The solution is an extension of the previous one-dimensional theory by Bredehoeft and Papadopulos [1965]. It provides a quantitative tool for analyzing the uncertainty of the horizontal heat and fluid flow. The analytical results demonstrate that horizontal flow of heat and fluid, if at values much smaller than those of the vertical, has a negligible effect on the vertical temperature distribution but becomes significant when it is comparable to the vertical.

  7. Diagnostic techniques for measuring temperature transients and stress transients in the first wall of an ICF reactor

    SciTech Connect

    Melamed, N.T.; Taylor, L.H.

    1983-01-01

    The primary challenge in the design of an Inertial Confinement Fusion (ICF) power reactor is to make the first wall survive the frequent explosions of the pellets. Westinghouse has proposed a dry wall design consisting of steel tubes coated with tantalum. This report describes the design of a test chamber and two diagnostic procedures for experimentally determining the reliability of the Westinghouse design. The test chamber simulates the x-ray and ion pulse irradiation of the wall due to a pellet explosion. The diagnostics consist of remote temperature sensing and surface deformation measurements. The chamber and diagnostics can also be used to test other first-wall designs.

  8. A transient free convection study with temperature-dependent viscosity in a square cavity with a local heat source

    NASA Astrophysics Data System (ADS)

    Astanina, M. S.; Sheremet, M. A.

    2016-04-01

    Unsteady natural convection inside of a differentially-heated square enclosure filled with a fluid of temperature-dependent viscosity has been numerically studied. A mathematical model formulated in the dimensionless stream function and vorticity has been solved by a finite difference method of the second order accuracy. The effect of dimensionless time and Prandtl number on streamlines and isotherms has been investigated for Ra = 105. The results clearly demonstrate an evolution of fluid flow and heat transfer in the case of variable viscosity fluid.

  9. Evaluation of Heat Pipe Working Fluids In The Temperature Range 450 to 700 K

    NASA Astrophysics Data System (ADS)

    Anderson, William G.; Rosenfeld, John H.; Angirasa, Devarakonda; Mi, Ye

    2004-02-01

    In the temperature range of 450-700 K, there are currently no working fluids that have been validated for heat pipes and loop heat pipes, with the exception of water in the lower portion of the range. This paper reviews a number of potential working fluid including several organic fluids, mercury, sulfur/iodine, and halides. Physical property data are used where available, and estimated where unavailable using standard methods. The halide salts appear to possess attractive properties, with good liquid transport factors, and suitable vapor pressures. Where nuclear radiation is not a consideration, other potential working fluids are aniline, naphthalene, toluene, and phenol. The limited available life test data available suggests that toluene, naphthalene, and some of the halides are compatible with stainless steel, while the other fluids have not been tested.

  10. Wide-band complex magnetic susceptibility measurements of magnetic fluids as a function of temperature

    NASA Astrophysics Data System (ADS)

    Fannin, P. C.; Kinsella, L.; Charles, S. W.

    1999-07-01

    Measurements of the complex magnetic susceptibility over the frequency and temperature ranges of 2 MHz-6 GHz and 20 to -100°C, respectively, are reported for the first time for a magnetic fluid. The fluid used was a colloidal suspension of magnetite particles of median diameter 9 nm in a hydrocarbon oil (isopar m). Resonance was observed and found to increase from approx 1.5 GHz to 3.3 GHz in the temperature range 20 to -50°C. The increase in resonant frequency is attributed to a decrease in thermal fluctuations with decrease in temperature. At frequencies below approximately 19 MHz, a significant drop in χ'( ω) with decrease in temperature over the temperature range 20 to -100°C, is observed and is attributed to the changes in the Néel and Brownian relaxation processes. Below -60°C, the temperature at which the suspension becomes solid, Brownian relaxation ceases to exist.

  11. Two-Phase Working Fluids for the Temperature Range 50 to 350 C

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Owzarski, P. C.

    1977-01-01

    The decomposition and corrosion of two-phase heat transfer liquids and metal envelopes have been investigated on the basis of molecular bond strengths and chemical thermodynamics. Potentially stable heat transfer fluids for the temperature range 100 C to 350 C have been identified, and reflux heat pipes tests initiated with 10 fluids and carbon steel and aluminum envelopes to experimentally establish corrosion behavior and noncondensable gas generation rates.

  12. 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.

  13. High-temperature chlorine-rich fluid in the martian crust: A precursor to habitability

    NASA Astrophysics Data System (ADS)

    Filiberto, Justin; Treiman, Allan H.; Giesting, Paul A.; Goodrich, Cyrena A.; Gross, Juliane

    2014-09-01

    We report scapolite in a melt inclusion in olivine in Nakhla, which is the first occurrence of Cl-scapolite found in a martian meteorite. Using terrestrial metamorphic experiments and modeling we constrain its origin. Cl-rich scapolite in Nakhla is consistent with formation from either a late stage Cl-rich, water-poor magma or magmatic Cl-rich hydrothermal brine at a minimum temperature of 700 °C. The temperature of hydrothermal activity recorded by the Cl-scapolite is significantly higher than the temperatures recorded by alteration minerals in Nakhla, and the fluid was Cl-rich, not CO2-rich. Our results demonstrate that high-temperature Cl-rich fluids were present within the martian crust, and any potential biologic activity would have to survive in these high temperatures and saline fluids. Halophiles can thrive in NaCl-rich systems but at significantly lower temperatures than those recorded by the scapolite. During cooling of the fluid, the system could have reached a habitable state for halophiles. Importantly, halophiles can survive the conditions of space if they are encased in salt crystals, and therefore chlorine-rich phases present an opportunity to investigate for extant life both on the surface of Mars and in martian meteorites.

  14. Fluid-inclusion evidence for previous higher temperatures in the miravalles geothermal field, Costa Rica

    USGS Publications Warehouse

    Bargar, K.E.; Fournier, R.O.

    1988-01-01

    Heating and freezing data were obtained for liquid-rich secondary fluid inclusions in magmatic quartz, hydrothermal calcite and hydrothermal quartz crystals from 19 sampled depths in eight production drill holes (PGM-1, 2, 3, 5, 10, 11, 12 and 15) of the Miravalles geothermal field in northwestern Costa Rica. Homogenization temperatures for 386 fluid inclusions range from near the present measured temperatures to as much as 70??C higher than the maximum measured well temperature of about 240??C. Melting-point temperature measurements for 76 fluid inclusions suggest a calculated salinity range of about 0.2-1.9 wt% NaCl equivalent. Calculated salinities as high as 3.1-4.0 wt% NaCl equivalent for 20 fluid inclusions from the lower part of drill hole PGM-15 (the deepest drill hole) indicate that higher salinity water probably was present in the deeper part of the Miravalles geothermal field at the time these fluid inclusions were formed. ?? 1988.

  15. The dissociation and equation of state of dense fluid oxygen at high pressures and high temperatures.

    PubMed

    Chen, Q F; Cai, L C; Zhang, Y; Gu, Y J

    2008-03-14

    The dissociation, pressure, and internal energy of dense fluid oxygen at high temperatures and densities have been calculated from the free-energy functions using the self-consistent fluid variational theory. In this paper, we focused on a mixture of oxygen atoms and molecules, and investigated the phenomenon of pressure dissociation at finite temperature. The single-shock Hugoniot derived from this equation of state agrees well with gas-gun experiments for pressure versus density. The equation of state and dissociation degree are predicted in the ranges of temperature of 5000-16,000 K and density of 0.1-4.5 g/cm(3). These data are formulated in the analytical forms of dissociation degree-density-temperature and pressure-density-temperature equation of state. PMID:18345911

  16. Temperature modulation of the vibrational responses of a flexible fluid-conveying pipe

    NASA Astrophysics Data System (ADS)

    Adelaja, Adekunle

    2013-12-01

    In this study, the nonlinear transverse vibration of a flexible pipe conveying hot, pressurized fluid is investigated. The pipe which is subjected to a pinned-pinned end condition extends as a result of several operating variables such as internal fluid temperature variation, pre-stress and internal pressurization. The equation of motion is solved analytically by hybrid Fourier-Laplace transforms, and the effects of inlet temperature, temperature gradient, and coefficient of area deformation are investigated on the natural frequencies and transverse dynamic response of the pipeline. While the inlet temperature and temperature gradient are found to be inversely proportional to the natural frequencies and amplitude of the dynamic response, increase in the coefficient of area deformation has little effect on the natural frequencies for the particular case considered.

  17. Properties of planetary fluids at high pressures and temperatures

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    Observational data obtained by the Voyager space probes to the giant planets Jupiter, Saturn, Uranus, and Neptune have provided valuable information, which is used to refine the picture of the nature of the interiors of these planets. Major results from the Voyager missions include observations of substantial magnetic fields and improved models of internal density distributions. The goal is to obtain equations of state and electrical conductivity data for planetary gases (H2 and He) and the ices (H2O, CH4, and NH3, and their mixtures), which are considered to be the major constituents of the giant planets. These data are needed to test theoretical data bases used to construct models of the chemical composition of planetary interiors, models which are consistent with observables such as mass, diameter, gravitational moments, rotation rate, and magnetic field. The 100 GPa (1 Mbar) pressures and several 1000 K temperatures in the giant planets can be achieved in the lab by the shock compression of liquid specimens. Results are briefly examined.

  18. Transient temperature and sea level response of a two-dimensional ocean-climate model to greenhouse gas increases

    SciTech Connect

    Harvey, L.D.D.

    1994-09-01

    A two-dimensional dynamical ocean model is coupled to an energy balance climate model and used to investigate the transient surface temperature and sea level response to greenhouse gas increases. For most experiments a step function surface-troposphere heating perturbation of 6 W/sq m is applied. A transient reduction in the thermohaline overturning flux of 15-30% occurs in most experiments, although in some cases a near-total circulation collapse occurs within the first 100 years and lasts 700-1000 years. The transient circulation decrease is attributed to the greater rate of downward penetration of the heating anomaly in downwelling rather than in upwelling regions and is not a result of reduced convection. For experiments in which the steady state circulation is qualitatively unchanged after a heating perturbation, the surface temperature response is roughly uniform with latitude, in the absence of ice and snow. However, in some cases a heating perturbation induces the transition from a one-cell to a two-cell overturning circulation, or causes a complete reversal in the direction of overturning when a single cell spans both hemispheres, causing marked latitudinal variations in the surface temperature response.

  19. Finite-temperature fluid-insulator transition of strongly interacting 1D disordered bosons.

    PubMed

    Michal, Vincent P; Aleiner, Igor L; Altshuler, Boris L; Shlyapnikov, Georgy V

    2016-08-01

    We consider the many-body localization-delocalization transition for strongly interacting one-dimensional disordered bosons and construct the full picture of finite temperature behavior of this system. This picture shows two insulator-fluid transitions at any finite temperature when varying the interaction strength. At weak interactions, an increase in the interaction strength leads to insulator [Formula: see text] fluid transition, and, for large interactions, there is a reentrance to the insulator regime. It is feasible to experimentally verify these predictions by tuning the interaction strength with the use of Feshbach or confinement-induced resonances, for example, in (7)Li or (39)K. PMID:27436894

  20. A method of computing the transient temperature of thick walls from arbitrary variation of adiabatic-wall temperature and heat-transfer coefficient

    NASA Technical Reports Server (NTRS)

    Hill, P R

    1958-01-01

    A method of calculating the temperature of thick walls has been developed in which the time series and the response to a unit triangle variation of surface temperature concepts are used, together with essentially standard formulas for transient temperature and heat flow into thick walls. The method can be used without knowledge of the mathematical tools of its development. The method is particularly suitable for determining the wall temperature in one-dimensional thermal problems in aeronautics where there is a continuous variation of the heat-transfer coefficient and adiabatic-wall temperature. The method also offers a convenient means for solving the inverse problem of determining the heat-flow history when temperature history is known.

  1. Impact of synovial fluid flow on temperature regulation in knee cartilage.

    PubMed

    Moghadam, Mohamadreza Nassajian; Abdel-Sayed, Philippe; Camine, Valérie Malfroy; Pioletti, Dominique P

    2015-01-21

    Several studies have reported an increase of temperature in cartilage submitted to cyclic sinusoidal loading. The temperature increase is in part due to the viscous behavior of this tissue, which partially dissipates the input mechanical energy into heat. While the synovial fluid flow within the intra-articular gap and inside the porous cartilage is supposed to play an important role in the regulation of the cartilage temperature, no specific study has evaluated this aspect. In the present numerical study, a poroelastic model of the knee cartilage is developed to evaluate first the temperature increase in the cartilage due to dissipation and second the impact of the synovial fluid flow in the cartilage heat transfer phenomenon. Our results showed that, the local temperature is effectively increased in knee cartilage due to its viscous behavior. The synovial fluid flow cannot significantly preventing this phenomenon. We explain this result by the low permeability of cartilage and the moderate fluid exchange at the surface of cartilage under deformation. PMID:25488136

  2. 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.

  3. Trefftz method for solving two-dimensional temperature field of boiling fluid flowing along the minichannel

    NASA Astrophysics Data System (ADS)

    Hożejowska, S.; Piasecka, M.; Hożejowski, L.

    2013-04-01

    The paper focuses on the numerical solution to two-dimensional temperature field of boiling liquid flowing along a vertical, asymmetrically heated minichannel with a rectangular cross-section. One of the walls of a minichannel is a DC supplied heating foil. The parallel walls are made of glass panes for thermal insulation and for observation of the fluid flow and the void fraction. A thin layer of thermosensitive liquid crystal paint on the outer side of the heating foil enabled to record two-dimensional temperature distribution of outer foil surface. The paper presents computations based on Trefftz method for finding two-dimensional temperature field of boiling liquid flowing along the minichannel. The presented research is limited only to a liquid phase of the two-phase mixture observed in the minichannel. The velocity of liquid flowing through the minichannel is represented by a piecewise linear approximating function. To solve energy equation for liquid phase, Trefftz functions specially generated for this purpose were employed. Temperature field in the fluid was approximated by a linear combination of Trefftz functions. Temperature at the interface between working fluid and foil amounts to the saturation temperature. Temperature distribution in the foil and the glass pane was also computed using proper Trefftz functions.

  4. Fluid Structure Interaction in a Cold Flow Test and Transient CFD Analysis of Out-of-Round Nozzles

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph; Brown, Andrew; McDaniels, David; Wang, Ten-See

    2010-01-01

    This viewgraph presentation describes two nozzle fluid flow interactions. They include: 1) Cold flow nozzle tests with fluid-structure interaction at nozzle separated flow; and 2) CFD analysis for nozzle flow and side loads of nozzle extensions with various out-of-round cases.

  5. The low temperature differential Stirling engine with working fluid operated on critical condition

    SciTech Connect

    Naso, V.; Dong, W.; Lucentini, M.; Capata, R.

    1998-07-01

    The research and development of low temperature differential Stirling engine has a great potential market since a lot of thermal energy at low temperature can supply it and the cost of this kind of engine is lower than general Stirling engine. The characteristics of low compression ratio and low differential temperature Stirling engine may be satisfied with working fluid compressed on critical conditions. By combining two phase heat transfer with forced convective flow in compression space and through the regenerator in the engine, a new heat transfer coefficient emerges capable of absorbing and releasing high heat fluxes without the corresponding low temperature increase. The current analysis focuses on the study of Stirling engines with working fluid compressed on critical conditions, thus at two-phase heat transfer in compression space and regenerator of the engine under forced convective flow conditions.

  6. Experimental apparatus for measuring the thermal diffusivity of pure fluids at high temperatures

    SciTech Connect

    Kruppa, B.; Jany, P.; Straub, J.

    1988-11-01

    Dynamic light scattering represents a suitable method for measuring the thermal diffusivity of optically transparent fluids. The classic application of the method is the immediate vicinity around the critical point due to its dependence upon the intensity of scattered light and its high sensitivity to undesired light scattering. By means of subsequent modifications of the experimental setup, the authors have been able to expand this region of applicability over the last 12 years and could systematically investigate numerous substances and their binary mixtures within a temperature range of 280 K < T < 350 K. Their planned investigation of fluids suitable for ORC-HP-technology necessitates performing measurements at higher temperatures and pressures. The experimental apparatus newly designed for this purpose is capable of sustaining a relatively high temperature constance at temperatures up to 700 K. Factors restricting the measurable range of state and their influence on the design of the sample cell are discussed.

  7. Identification of an average temperature and a dynamical pressure in a multitemperature mixture of fluids.

    PubMed

    Gouin, Henri; Ruggeri, Tommaso

    2008-07-01

    We present a classical approach to a mixture of compressible fluids when each constituent has its own temperature. The introduction of an average temperature together with the entropy principle dictates the classical Fick law for diffusion and also novel constitutive equations associated with the difference of temperatures between the components. The constitutive equations fit with results recently obtained through a Maxwellian iteration procedure in extended thermodynamics theory of multitemperature mixtures. The differences of temperatures between the constituents imply the existence of a dynamical pressure even if the fluids have a zero bulk viscosity. The nonequilibrium dynamical pressure can be measured and may be convenient in several physical situations, such as, for example, in cosmological circumstances where--as many authors assert--a dynamical pressure played a major role in the evolution of the early universe. PMID:18764046

  8. Noncontact temperature measurements in the microgravity fluids and transport phenomena discipline

    NASA Technical Reports Server (NTRS)

    Salzman, Jack

    1988-01-01

    The program of activities within the Microgravity Fluids and Transport Phenomena Discipline has been structured to enable the systematic pursuit of an increased understanding of low gravity fluid behavior/phenomena in a way which ensures that the results are appropriate to the widest range of applications. This structure is discussed and an overview of some of the activities which are underway is given. Of significance is the fact that in the majority of the current and planned activities, the measurement and, or control of the fluid temperature is a key experiment requirement. In addition, many of the experiments require that the temperature measurement be nonintrusive. A description of these requirements together with the current techniques which are being employed or under study to make these measurements is also discussed.

  9. Two-phase working fluids for the temperature range of 50 to 350 deg, phase 2

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Hartl, J. H.

    1980-01-01

    Several two phase heat transfer fluids were tested in aluminum and carbon steel reflux capsules for over 25,000 hours at temperatures up to 300 C. Several fluids showed very good stability and would be useful for long duration heat transfer applications over the range 100 to 350 C. Instrumentation for the measurement of surface tension and viscosity were constructed for use with heat transfer fluids over the temperature range 0 to 300 C and with pressures from 0 to 10 atmospheres. The surface tension measuring device constructed requires less than a 1.0 cc sample and displays an accuracy of about 5 percent in preliminary tests, while the viscometer constructed for this program requires a 0.05 cc sample and shows an accuracy of about 5 percent in initial tests.

  10. Single Event Transient Analysis of an SOI Operational Amplifier for Use in Low-Temperature Martian Exploration

    NASA Technical Reports Server (NTRS)

    Laird, Jamie S.; Scheik, Leif; Vizkelethy, Gyorgy; Mojarradi, Mohammad M; Chen, Yuan; Miyahira, Tetsuo; Blalock, Benjamin; Greenwell, Robert; Doyle, Barney

    2006-01-01

    The next generation of Martian rover#s to be launched by JPL are to examine polar regions where temperatures are extremely low and the absence of an earth-like atmosphere results in high levels of cosmic radiation at ground level. Cosmic rays lead to a plethora of radiation effects including Single Event Transients (SET) which can severely degrade microelectronic functionality. As such, a radiation-hardened, temperature compensated CMOS Single-On-Insulator (SOI) Operational Amplifier has been designed for JPL by the University of Tennessee and fabricated by Honeywell using the SOI V process. SOI technology has been shownto be far less sensitive to transient effects than both bulk and epilayer Si. Broad beam heavy-ion tests at the University of Texas A&M using Kr and Xebeams of energy 25MeV/amu were performed to ascertain the duration and severity of the SET for the op-amp configured for a low and high gain application. However, some ambiguity regarding the location of transient formation required the use of a focused MeV ion microbeam. A 36MeV O6(+) microbeam. the Sandia National Laboratory (SNL) was used to image and verify regions of particular concern. This is a viewgraph presentation

  11. Calcium regulation by temperature-sensitive transient receptor potential channels in human uveal melanoma cells.

    PubMed

    Mergler, Stefan; Derckx, Raissa; Reinach, Peter S; Garreis, Fabian; Böhm, Arina; Schmelzer, Lisa; Skosyrski, Sergej; Ramesh, Niraja; Abdelmessih, Suzette; Polat, Onur Kerem; Khajavi, Noushafarin; Riechardt, Aline Isabel

    2014-01-01

    Uveal melanoma (UM) is both the most common and fatal intraocular cancer among adults worldwide. As with all types of neoplasia, changes in Ca(2+) channel regulation can contribute to the onset and progression of this pathological condition. Transient receptor potential channels (TRPs) and cannabinoid receptor type 1 (CB1) are two different types of Ca(2+) permeation pathways that can be dysregulated during neoplasia. We determined in malignant human UM and healthy uvea and four different UM cell lines whether there is gene and functional expression of TRP subtypes and CB1 since they could serve as drug targets to either prevent or inhibit initiation and progression of UM. RT-PCR, Ca(2+) transients, immunohistochemistry and planar patch-clamp analysis probed for their gene expression and functional activity, respectively. In UM cells, TRPV1 and TRPM8 gene expression was identified. Capsaicin (CAP), menthol or icilin induced Ca(2+) transients as well as changes in ion current behavior characteristic of TRPV1 and TRPM8 expression. Such effects were blocked with either La(3+), capsazepine (CPZ) or BCTC. TRPA1 and CB1 are highly expressed in human uvea, but TRPA1 is not expressed in all UM cell lines. In UM cells, the CB1 agonist, WIN 55,212-2, induced Ca(2+) transients, which were suppressed by La(3+) and CPZ whereas CAP-induced Ca(2+) transients could also be suppressed by CB1 activation. Identification of functional TRPV1, TRPM8, TRPA1 and CB1 expression in these tissues may provide novel drug targets for treatment of this aggressive neoplastic disease. PMID:24084605

  12. Transient infrared temperature measurements of liquid-fuel surfaces: results of studies of flames spread over liquids.

    PubMed

    Konishi, T; Ito, A; Saito, K

    2000-08-20

    An infrared thermograph technique with an 8-12-microm spectral range was used to measure transient two-dimensional profiles of liquid (1-propanol) surface temperatures. An IR camera was placed over the liquid, allowing us to observe the fuel surface through propanol vapor. To use this technique, one must know the emissivity of the liquid surface and the IR absorption of both the liquid propanol and the propanol vapor. The emissivity of the liquid propanol was determined with a fine thermocouple temperature measurement, IR absorption with the propanol vapor was calibrated with a blackbody source, and IR absorption with a liquid propanol was theoretically estimated. The accuracy of our infrared thermograph technique proved to be better than 97% in detecting the liquid-surface temperature with a temperature sensitivity of 0.1 degrees C and a time response of 30 ms. PMID:18350009

  13. DESTRUCTION OF PCB-CONTAMINATED SOILS WITH A HIGH-TEMPERATURE FLUID-WALL (HTFW) REACTOR

    EPA Science Inventory

    The objective of this project is to demonstrate the feasibility of a high temperature fluid-wall (HTFW) Reactor to detoxify biorefractory hazardous substances, as well as soils contaminated with hazardous materials, such as PCBs, dioxins, and organophosphates. A typical HTFW Reac...

  14. Computational fluid dynamics model of avian tracheal temperature control as a model for extant and extinct animals.

    PubMed

    Sverdlova, N S; Arkali, F; Witzel, U; Perry, S F

    2013-10-01

    Respiratory evaporative cooling is an important mechanism of temperature control in bird. A computational simulation of the breathing cycle, heat and water loss in anatomical avian trachea/air sac model has not previously been conducted. We report a first attempt to simulate a breathing cycle in a three-dimensional model of avian trachea and air sacs (domestic fowl) using transient computational fluid dynamics. The airflow in the trachea of the model is evoked by changing the volume of the air sacs based on the measured tidal volume and inspiratory/expiratory times for the domestic fowl. We compare flow parameters and heat transfer results with in vivo data and with our previously reported results for a two-dimensional model. The total respiratory heat loss corresponds to about 13-19% of the starvation metabolic rate of domestic fowl. The present study can lend insight into a possible thermoregulatory function in species with long necks and/or a very long trachea, as found in swans and birds of paradise. Assuming the structure of the sauropod dinosaur respiratory system was close to avian, the simulation of the respiratory temperature control (using convective and evaporative cooling) in the extensively experimentally studied domestic fowl may also help in making simulations of respiratory heat control in these extinct animals. PMID:23797184

  15. On the integral-balance approach to the transient heat conduction with linearly temperature-dependent thermal diffusivity

    NASA Astrophysics Data System (ADS)

    Fabre, Antoine; Hristov, Jordan

    2016-04-01

    Closed form approximate solutions to nonlinear transient heat conduction with linearly temperature-dependent thermal diffusivity have been developed by the integral-balance integral method under transient conditions. The solutions uses improved direct approaches of the integral method and avoid the commonly used linearization by the Kirchhoff transformation. The main steps in the new solutions are improvements in the integration technique of the double-integration technique and the optimization of the exponent of the approximate parabolic profile with unspecified exponent. Solutions to Dirichlet and Neumann boundary condition problems have been developed as examples by the classical Heat-balance integral method (HBIM) and the Double-integration method (DIM). Additional examples with HBIM and DIM solutions to cases when the Kirchhoff transform is initially applied have been developed.

  16. Transient Modeling and Analysis of a Metabolic Heat-Regenerated Temperature Swing Adsorption (MTSA) System for a PLSS

    NASA Technical Reports Server (NTRS)

    Iacomini, Christie; Powers, Aaron; Speight, Garland; Padilla, Sebastian; Paul, Heather L.

    2009-01-01

    A Metabolic heat-regenerated Temperature Swing Adsorption (MTSA) system is being developed for carbon dioxide, water and thermal control in a lunar and martian portable life support system (PLSS). A previous system analysis was performed to evaluate the impact of MTSA on PLSS design. That effort was Mars specific and assumed liquid carbon dioxide (LCO2) coolant made from martian resources. Transient effects were not considered but rather average conditions were used throughout the analysis. This effort takes into further consideration the transient effects inherent in the cycling MTSA system as well as assesses the use of water as coolant. Standard heat transfer, thermodynamic, and heat exchanger methods are presented to conduct the analysis. Assumptions and model verification are discussed. The tool was used to perform various system studies. Coolant selection was explored and takes into account different operational scenarios as the minimum bed temperature is driven by the sublimation temperature of the coolant (water being significantly higher than LCO2). From this, coolant mass is sized coupled with sorbent bed mass because MTSA adsorption performance decreases with increasing sublimation temperature. Reduction in heat exchanger performance and even removal of certain heat exchangers, like a recuperative one between the two sorbent beds, is also investigated. Finally, the coolant flow rate is varied over the cycle to determine if there is a more optimal means of cooling the bed from a mass perspective. Results of these studies and subsequent recommendations for system design are presented.

  17. Water Temperature, Voluntary Drinking and Fluid Balance in Dehydrated Taekwondo Athletes

    PubMed Central

    Khamnei, Saeed; Hosseinlou, Abdollah; Zamanlu, Masumeh

    2011-01-01

    Voluntary drinking is one of the major determiners of rehydration, especially as regards exercise or workout in the heat. The present study undertakes to search for the effect of voluntary intake of water with different temperatures on fluid balance in Taekwondo athletes. Six young healthy male Taekwondo athletes were dehydrated by moderate exercise in a chamber with ambient temperature at 38-40°C and relative humidity between 20-30%. On four separate days they were allowed to drink ad libitum plane water with the four temperatures of 5, 16, 26, and 58°C, after dehydration. The volume of voluntary drinking and weight change was measured; then the primary percentage of dehydration, sweat loss, fluid deficit and involuntary dehydration were calculated. Voluntary drinking of water proved to be statistically different in the presented temperatures. Water at 16°C involved the greatest intake, while fluid deficit and involuntary dehydration were the lowest. Intake of water in the 5°C trial significantly correlated with the subject’s plasma osmolality change after dehydration, yet it showed no significant correlation with weight loss. In conclusion, by way of achieving more voluntary intake of water and better fluid state, recommending cool water (~16°C) for athletes is in order. Unlike the publicly held view, drinking cold water (~5°C) does not improve voluntary drinking and hydration status. Key points For athletes dehydrated in hot environments, maximum voluntary drinking and best hydration state occurs with 16°C water. Provision of fluid needs and thermal needs could be balanced using 16°C water. Drinking 16°C water (nearly the temperature of cool tap water) could be recommended for exercise in the heat. PMID:24149564

  18. Temperature change, dentinal fluid flow and cuspal displacement during resin composite restoration.

    PubMed

    Ratih, D N; Palamara, J E A; Messer, H H

    2007-09-01

    Dentin-bonding agents and resin composite materials typically require light activation for polymerization. Light curing generates heat, which may influence dentinal fluid flow (DFF) and cuspal displacement. This study investigated the relationship among temperature increase, DFF and cuspal displacement in extracted human maxillary premolars with a mesial occlusal distal (MOD) cavity preparation. Two types of curing light were compared. Temperature changes were measured using thermocouples located on the occlusal cavity floor and at the pulp-dentine junction, during polymerization of bonding agent and resin composite material. DFF and cuspal displacement were measured simultaneously using automated flow measurement apparatus and direct current differential transformers respectively. Temperature increases of up to 15 degrees C were recorded during the restoration procedures. A quartz tungsten halogen (QTH) unit produced a significantly greater temperature increase than a light-emitting diode unit and curing of the bonding agent generated less temperature increase than curing of the resin composite. Heating due to exothermic reaction during polymerization of bonding agent and resin was not significantly different between light sources or between bonding and curing (P > 0.05). The QTH unit produced both greater inward fluid flow and cuspal displacement during the irradiation of bonding agent and resin composite than the light-emitting diode unit. There was not a simple relationship between temperature increase, fluid movement and cuspal displacement. From a clinical point of view, the light-emitting diode unit can be considered preferable to the QTH light, because it caused significantly smaller temperature increase, fluid shift and cuspal displacement. PMID:17716269

  19. Temperature variation in the dark cosmic fluid in the late universe

    NASA Astrophysics Data System (ADS)

    Brevik, Iver

    2016-03-01

    A one-component dark energy fluid model of the late universe is considered (w < -1) when the fluid, initially assumed laminar, makes a transition into a turbulent state of motion. Spatial isotropy is assumed so that only the bulk viscosities are included (ζ in the laminar epoch and ζturb in the turbulent epoch). Both viscosities are assumed to be constants. We derive a formula, new as far as we know, for the time dependence of the temperature T(t) in the laminar case when viscosity is included. Assuming that the laminar/turbulent transition takes place at some time ts before the big rip is reached, we then analyze the positive temperature jump experienced by the fluid at t = t∗ if ζturb > ζ. This is just as one would expect physically. The corresponding entropy production is also considered. A special point emphasized in the paper is the analogy that exists between the cosmic fluid and a so-called Maxwell fluid in viscoelasticity.

  20. Loop Heat Pipe Transient Behavior Using Heat Source Temperature for Set Point Control with Thermoelectric Converter on Reservoir

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

    2011-01-01

    The LHP operating temperature is governed by the saturation temperature of its reservoir. Controlling the reservoir saturation temperature is commonly done by cold biasing the reservoir and using electrical heaters to provide the required control power. With this method, the loop operating temperature can be controlled within 0.5K or better. However, because the thermal resistance that exists between the heat source and the LHP evaporator, the heat source temperature will vary with its heat output even if the LHP operating temperature is kept constant. Since maintaining a constant heat source temperature is of most interest, a question often raised is whether the heat source temperature can be used for LHP set point temperature control. A test program with a miniature LHP was carried out to investigate the effects on the LHP operation when the control temperature sensor was placed on the heat source instead of the reservoir. In these tests, the LHP reservoir was cold-biased and was heated by a control heater. Test results show that it was feasible to use the heat source temperature for feedback control of the LHP operation. In particular, when a thermoelectric converter was used as the reservoir control heater, the heat source temperature could be maintained within a tight range using a proportional-integral-derivative or on/off control algorithm. Moreover, because the TEC could provide both heating and cooling to the reservoir, temperature oscillations during fast transients such as loop startup could be eliminated or substantially reduced when compared to using an electrical heater as the control heater.

  1. Force generation and temperature-jump and length-jump tension transients in muscle fibers.

    PubMed

    Davis, J S; Rodgers, M E

    1995-05-01

    Muscle tension rises with increasing temperature. The kinetics that govern the tension rise of maximally Ca(2+)-activated, skinned rabbit psoas fibers over a temperature range of 0-30 degrees C was characterized in laser temperature-jump experiments. The kinetic response is simple and can be readily interpreted in terms of a basic three-step mechanism of contraction, which includes a temperature-sensitive rapid preequilibrium(a) linked to a temperature-insensitive rate-limiting step and followed by a temperature-sensitive tension-generating step. These data and mechanism are compared and contrasted with the more complex length-jump Huxley-Simmons phases in which all states that generate tension or bear tension are perturbed. The rate of the Huxley-Simmons phase 4 is temperature sensitive at low temperatures but plateaus at high temperatures, indicating a change in rate-limiting step from a temperature-sensitive (phase 4a) to a temperature-insensitive reaction (phase 4b); the latter appears to correlate with the slow, temperature-insensitive temperature-jump relaxation. Phase 3 is absent in the temperature-jump, which excludes it from tension generation. We confirm that de novo tension generation occurs as an order-disorder transition during phase 2slow and the equivalent, temperature-sensitive temperature-jump relaxation. PMID:7612845

  2. Temperatures of quartz cementation in Jurassic sandstones from the Norwegian continental shelf -- evidence from fluid inclusions

    SciTech Connect

    Walderhaug, O. )

    1994-04-01

    Recent studies of fluid inclusions in quartz overgrowths have shown quartz cementation to have taken place at temperatures within the range 60--145 C in several sandstones from the North Sea and offshore mid-Norway (Malley et al. 1986; Konnerup-Madsen and Dypvik 1988; Burley et al. 1989; Walderhaug 1990; Ehrenberg 1990; Saigal et al. 1992; Nedkvitne et al. 1993). This study aims at determining whether these results are typical for quartz cementation of sandstones by presenting homogenization temperatures for 274 aqueous and 366 hydrocarbon inclusions in quartz overgrowths from Jurassic reservoir sandstones on the Norwegian continental shelf, and by reviewing previously published fluid-inclusion data. Possible explanations for different ranges of homogenization temperatures in different sandstones are also discussed, and possible sources of quartz cement and the effect of hydrocarbon emplacement on quartz cementation are considered.

  3. Liquid Gallium based temperature sensitive functional fluid dispersing chemically synthesized FeMB nanoparticles

    NASA Astrophysics Data System (ADS)

    Park, H. S.; Cao, L. F.; Dodbiba, G.; Fujita, T.

    2009-02-01

    In this work, FeMB (M = Nb, V) nanoparticles were first reported to be synthesized by a chemical method, from reduction of FeCl2, NbF5 (and NH4VO3) using NaBH4 as a reducing agent in aqueous solution. A new temperature sensitive functional fluid was then prepared by dispersing silica coated FeNbVB nanoparticles in liquid gallium. The result shows that the FeNbVB nanoparticles exhibit an oxidation resistance better than that of FeNbB nanoparticles. The FeNbVB nanoparticles were in the size range of 30 - 50 nm and the thickness of silica layer was observed about 10 nm by means of transmission electron microscopy. The magnetization of the synthesized particles and fluid shows a temperature dependency within the testing temperature range of 293 - 353 K, which indicated their application potential in magneto-caloric energy conversion devices.

  4. 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

    The formation of aqueous organic sulfur compounds in hydrothermal systems remains poorly constrained, despite their potential significance in 'prebiotic' chemistry and the origin of life. The simplest - methanethiol (CH3SH) - has been implicated as a critical abiogenic precursor to the establishment of primitive microbial metabolism in early Earth hydrothermal settings. It also represents a readily-utilized substrate for microbial sulfate-reducing communities and a potential intermediate species in abiotic CH4 formation. To assess the abundance of CH3SH and factors regulating its stability under hydrothermal conditions we measured CH3SH concentrations in a suite of hydrothermal fluids collected from the Rainbow, Lucky Strike, TAG and Lost City hydrothermal sites located on the Mid-Atlantic Ridge. Fluids were collected using isobaric gas-tight samplers and analyzed for CH3SH by shipboard purge-and-trap gas chromatography. Measured concentrations at Rainbow (1.2 -- 223nM), Lucky Strike (1.1 -- 26nM), TAG (8.5 -- 11nM) and Lost City (1.6 -- 3.0nM) are all substantially lower than predicted for thermodynamic equilibrium with CO2, H2 and H2S at measured vent conditions. The highest concentrations (91 -- 223nM), however, were observed at Rainbow in intermediate temperature (128 -- 175°C) H2-rich fluids that may have undergone conductive cooling. Increased concentrations with decreasing temperature is consistent with the thermodynamic drive for the formation from CO2, suggesting a possible abiotic origin for CH3SH in some fluids. Substantially lower concentrations in the low temperature fluids at Lost City are consistent with the extremely low levels of CO2 and H2S in these fluids. Other possible sources of CH3SH to vent fluids must be considered, however, and include thermal alteration of biomass present in low-temperature environments and microbial consortia that produce CH3SH as a byproduct of anaerobic methane oxidation. Current models for the emergence of primordial

  5. Transient pool boiling in microgravity

    NASA Technical Reports Server (NTRS)

    Ervin, J. S.; Merte, H., Jr.; Keller, R. B.; Kirk, K.

    1992-01-01

    Transient nucleate pool boiling experiments using R113 are conducted for short times in microgravity and in earth gravity with different heater surface orientations and subcoolings. The heating surface is a transparent gold film sputtered on a quartz substrate, which simultaneously provides surface temperature measurements and permits viewing of the boiling process from beneath. For the microgravity experiments, which have uniform initial temperatures and no fluid motion, the temperature distribution in the R 113 at the moment of boiling inception is known. High speed cameras with views both across and through the heating surface record the boiling spread across the heater surface, which is classified into six distinct categories.

  6. The temperature dependence of the optical anisotropy in magnetic fluids: birefringence and dichroism

    NASA Astrophysics Data System (ADS)

    Yusuf, N. A.; Manasrah, D. A.; Abdallah, M. A.; Abu-Safia, H.; Abu-Aljarayesh, I.

    1994-11-01

    The temperature dependence of birefringence, δ, and dichroism, Δ A, in Fe 3O 4 Isopar-M based magnetic fluids have been investigated in the temperature range 100 < T < 320 K and in magnetic fields up to 3 kOe. The results show that birefringence and dichroism for a given concentration and at a given field are zero below a certain temperature Ts, and then both increase with temperature until they reach a maximum at a temperature Tm, and then decrease with temperature for T > Tm. The values of Tm and Ts are found to vary with concentration and the applied field. The results also show that δ- H2 and Δ A-H2 curves deviate from linearity. This deviation is attributed to interparticle interactions, the orientation of pre-existing clusters, and the field-induced chain formation.

  7. The electromagnetic force field, fluid flow field and temperature profiles in levitated metal droplets

    NASA Technical Reports Server (NTRS)

    El-Kaddah, N.; Szekely, J.

    1982-01-01

    A mathematical representation was developed for the electromagnetic force field, the flow field, the temperature field (and for transport controlled kinetics), in a levitation melted metal droplet. The technique of mutual inductances was employed for the calculation of the electromagnetic force field, while the turbulent Navier - Stokes equations and the turbulent convective transport equations were used to represent the fluid flow field, the temperature field and the concentration field. The governing differential equations, written in spherical coordinates, were solved numerically. The computed results were in good agreement with measurements, regarding the lifting force, and the average temperature of the specimen and carburization rates, which were transport controlled.

  8. Molecular dissociation and shock-induced cooling in fluid nitrogen at high densities and temperatures

    NASA Technical Reports Server (NTRS)

    Radousky, H. B.; Nellis, W. J.; Ross, M.; Hamilton, D. C.; Mitchell, A. C.

    1986-01-01

    Radiative temperatures and electrical conductivities were measured for fluid nitrogen compressed dynamically to pressures of 18-90 GPa, temperatures of 4000-14,000 K, and densities of 2-3 g/cu cm. The data show a continuous phase transition above 30 GPa shock pressure and confirm that (delta-P/delta-T)v is less than 0, as indicated previously by Hugoniot equation-of-state experiments. The first observation of shock-induced cooling is also reported. The data are interpreted in terms of molecular dissociation, and the concentration of dissociated molecules is calculated as a function of density and temperature.

  9. Transient temperature responses of hydronic radiant floor heating system by different pipe embedding depth and water supply condition.

    PubMed

    Chung, K S; Sohn, J Y; Baik, Y K; Kang, J S

    1993-07-01

    "Ondol" is a Korean unique heating system. It is a specific radiant floor heating system using combustion heat of briquette or timber in Korea. Such traditional "Ondol" is changed to radiant heating system with pipe-coil embedded in the floor or slab. This study has contributed to the understandings of the transient behaviours of Ondol-heated floor panels and enclosure exposed to this type of heating system. The result is that the water supply temperature had a large effect on the rate of increase in floor surface and room air temperature. But, in spite of a higher water supply temperature, the heat flow rate was not increased considerably. The shallow pipe embedding depths, of course, result in a low heat flow rate. PMID:8373479

  10. Fluid-inclusion evidence for past temperature fluctuations in the Kilauea East Rift Zone geothermal area, Hawaii

    USGS Publications Warehouse

    Bargar, K.E.; Keith, T.E.C.; Trusdell, F.A.

    1995-01-01

    Heating and freezing data were obtained for fluid inclusions in hydrothermal quartz, calcite, and anhydrite from several depths in three scientific observation holes drilled along the lower East Rift Zone of Kilauea volcano, Hawaii. Comparison of measured drill-hole temperatures with fluid-inclusion homogenization-temperature (Th) data indicates that only about 15% of the fluid inclusions could have formed under the present thermal conditions. The majority of fluid inclusions studied must have formed during one or more times in the past when temperatures fluctuated in response to the emplacement of nearby dikes and their subsequent cooling. -from Authors

  11. Forearm blood flow during body temperature transients produced by leg exercise

    NASA Technical Reports Server (NTRS)

    Wenger, C. B.; Roberts, M. F.; Stolwijk, J. A. J.; Nadel, E. R.

    1975-01-01

    Subjects exercised for 30 min on a bicycle ergometer at 30, 50, and 70% of maximal aerobic power in ambient temperatures of 15, 25, and 35 C and vapor pressures of less than 18 torr. Exercise was used to vary internal temperature during an experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Forearm skin temperature was fixed at about 36.5 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at eight skin sites. Forearm blood flow was measured by electrocapacitance plethysmography. Data are well accounted for by a linear equation independent of exercise intensity, although some subjects showed an equivocal vasodilator effect of exercise.

  12. Ramp temperature and Dufour effects on transient MHD natural convection flow past an infinite vertical plate in a porous medium

    NASA Astrophysics Data System (ADS)

    Marneni, Narahari; Tippa, Sowmya; Pendyala, Rajashekhar

    2015-12-01

    Analytical investigation of the unsteady natural convection flow along an infinite vertical plate embedded in a porous medium subjected to a ramped temperature boundary condition has been performed in the presence of magnetic field, thermal radiation, heat generation or absorption, chemical reaction and Dufour effect. The governing equations for momentum, energy and concentration have been solved using the Laplace transform technique. The closed-form exact solutions for the velocity, temperature and concentration fields as well as the skin-friction, Nusselt and Sherwood numbers are obtained without any restrictions. The influence of pertinent parameters on the fluid velocity, temperature, skin-friction and Nusselt number have been discussed in detailed through graphs. The natural convection due to ramped wall temperature (RWT) has also been compared with that of the constant wall temperature (CWT). It is observed that the fluid velocity and temperature profiles are greater in case of CWT than the case of RWT. Also it is noticed that the flow accelerates with increasing values of heat source parameter, permeability parameter and Dufour number while the flow retardation is observed with increasing values of radiation parameter, magnetic field parameter and Schmidt number.

  13. Modular High-Temperature Gas-Cooled Reactor short term thermal response to flow and reactivity transients

    SciTech Connect

    Cleveland, J.C.

    1988-01-01

    The analyses reported here have been conducted at the Oak Ridge National Laboratory (ORNL) for the US Nuclear Regulatory Commission's (NRC's) Division of Regulatory Applications of the Office of Nuclear Regulatory Research. The short-term thermal response of the Modular High-Temperature Gas-Cooled Reactor (MHTGR) is analyzed for a range of flow and reactivity transients. These include loss of forced circulation (LOFC) without scram, moisture ingress, spurious withdrawal of a control rod group, hypothetical large and rapid positive reactivity insertion, and a rapid core cooling event. The coupled heat transfer-neutron kinetics model is also described.

  14. 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.

  15. Modelling near subsurface temperature with mixed type boundary condition for transient air temperature and vertical groundwater flow

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev Ranjan; Ramana, D. V.; Singh, R. N.

    2012-10-01

    Near-subsurface temperatures have signatures of climate change. Thermal models of subsurface have been constructed by prescribing time dependent Dirichlet type boundary condition wherein the temperature at the soil surface is prescribed and depth distribution of temperature is obtained. In this formulation it is not possible to include the relationship between air temperatures and the temperature of soil surface. However, if one uses a Robin type boundary condition, a transfer coefficient relates the air and soil surface temperatures which helps to determine both the temperature at the surface and at depth given near surface air temperatures. This coefficient is a function of meteorological conditions and is readily available. We have developed such a thermal model of near subsurface region which includes both heat conduction and advection due to groundwater flows and have presented numerical results for changes in the temperature-depth profiles for different values of transfer coefficient and groundwater flux. There are significant changes in temperature and depth profiles due to changes in the transfer coefficient and groundwater flux. The analytical model will find applications in the interpretation of the borehole geothermal data to extract both climate and groundwater flow signals.

  16. Low-noise rotating sample holder for ultrafast transient spectroscopy at cryogenic temperatures.

    PubMed

    Fanciulli, R; Cerjak, I; Herek, J L

    2007-05-01

    We present the design and testing of a rotating device that fits within a commercial helium cryostat and is capable of providing at 4 K a fresh sample surface for subsequent shots of a 1-10 kHz amplified pulsed laser. We benchmark this rotator in a transient-absorption experiment on molecular switches. After showing that the device introduces only a small amount of additional noise, we demonstrate how the effect of signal degradation due to high fluence is completely resolved. PMID:17552807

  17. Low-noise rotating sample holder for ultrafast transient spectroscopy at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Fanciulli, R.; Cerjak, I.; Herek, J. L.

    2007-05-01

    We present the design and testing of a rotating device that fits within a commercial helium cryostat and is capable of providing at 4K a fresh sample surface for subsequent shots of a 1-10kHz amplified pulsed laser. We benchmark this rotator in a transient-absorption experiment on molecular switches. After showing that the device introduces only a small amount of additional noise, we demonstrate how the effect of signal degradation due to high fluence is completely resolved.

  18. Coupling of high temperature heat transfer and supersonic fluid dynamics studies

    NASA Astrophysics Data System (ADS)

    Kennedy, Kevin Drew

    1998-11-01

    A numerical investigation of time dependent, high speed convective heat transfer has been conducted. A state-of- the-art finite volume fluid dynamic flow solver was selected for modification to predict the effects of convective heat transfer on the surface boundary layer. A finite volume heat transfer program was developed based on the same methodology as the fluid flow solver. These two codes were tied together in a time accurate, weakly coupled form that makes use of an advanced message passaging technique. This message passaging technique passes information at the boundary interface between the two computer codes in a structured format. This information contains the data needed to control the operation of each code in a time accurate mode. The primary objective of the current research program was to understand the time accurate, unsteady, characteristics of a supersonic boundary layer in the presence of convective heat transfer. This research could be used in conjunction with infrared imaging sensors that are mounted in the nose cone of a missile. These sensors receive information that passes through a changing thermal boundary, which affects what the sensor detects. If the boundary layer and the thermal profile of the imaging window could be predicted as a function of time, then the appropriate correction could be made to the imaging sensor. The ability to model a time accurate boundary layer in the presence of heat transfer is demonstrated in this research. Both the fluid flow solver and the heat conduction code are modeled against steady and unsteady theoretical examples. Together, these codes are combined into one working module and validated against a sample case. The sample case modeled is that of a typical sensor window found on a endo-atmospheric interceptor. The surface of the window experiences high temperature stagnating flow, resulting in heat flowing into the sensor window. The window is cooled by an internal layer of cold flowing nitrogen

  19. A non-intrusive partitioned approach to couple smoothed particle hydrodynamics and finite element methods for transient fluid-structure interaction problems with large interface motion

    NASA Astrophysics Data System (ADS)

    Li, Zhe; Leduc, Julien; Nunez-Ramirez, Jorge; Combescure, Alain; Marongiu, Jean-Christophe

    2015-04-01

    We propose a non-intrusive numerical coupling method for transient fluid-structure interaction (FSI) problems simulated by means of different discretization methods: smoothed particle hydrodynamics (SPH) and finite element (FE) methods for the fluid and the solid sub-domains, respectively. As a partitioned coupling method, the present algorithm can ensure a zero interface energy during the whole period of numerical simulation, even in the presence of large interface motion. In other words, the time integrations of the two sub-domains (second order Runge-Kutta scheme for fluid and Newmark integrator for solid) are synchronized. Thanks to this energy-conserving feature, one can preserve the minimal order of accuracy in time and the numerical stability of the FSI simulations, which are validated with a 1D and a 2D trivial numerical test cases. Additionally, some other 2D FSI simulations involving large interface motion have also been carried out with the proposed SPH-FE coupling method. Finally, an example of aquaplaning problem is given in order to show the feasibility of such coupling method in multi-dimensional applications with complicated structural geometries.

  20. Effect of temperature and pore fluid on the strength of porous limestone

    NASA Astrophysics Data System (ADS)

    Lisabeth, Harrison P.; Zhu, Wenlu

    2015-09-01

    The presence of pore fluid in rocks generally reduces brittle strength. The role of water weakening in porous carbonate rocks and the effect of enhanced deformation on concomitant transport property evolution are poorly understood. The interaction between pore fluid and deformation mechanisms in carbonate rocks is complicated by crystal plasticity and solubility in calcite at low temperatures and pressures. To explore this system, we perform conventional triaxial deformation experiments on Indiana Limestone (~16% porosity) over a range of temperatures (23-75°C) and effective confining pressures (10-50 MPa). Samples are deformed with pore fluids of different saturation states with respect to calcite host rock. Samples tend to fail by distributed deformation. Sample permeability is reduced by up to an order of magnitude during deformation, even in samples exhibiting dilatancy. Compactive yield strength, associated with shear-enhanced compaction, is greatly reduced in saturated samples compared to dry samples. Dilatancy is suppressed and compaction enhanced at elevated pressures. Greater weakening effects are observed when pore fluid is far-from-equilibrium with carbonate rock. Observed weakening results from the interaction between microcracking, mechanical twinning, and pressure solution.

  1. The Pyrexia transient receptor potential channel mediates circadian clock synchronization to low temperature cycles in Drosophila melanogaster

    PubMed Central

    Wolfgang, Werner; Simoni, Alekos; Gentile, Carla; Stanewsky, Ralf

    2013-01-01

    Circadian clocks are endogenous approximately 24 h oscillators that temporally regulate many physiological and behavioural processes. In order to be beneficial for the organism, these clocks must be synchronized with the environmental cycles on a daily basis. Both light : dark and the concomitant daily temperature cycles (TCs) function as Zeitgeber (‘time giver’) and efficiently entrain circadian clocks. The temperature receptors mediating this synchronization have not been identified. Transient receptor potential (TRP) channels function as thermo-receptors in animals, and here we show that the Pyrexia (Pyx) TRP channel mediates temperature synchronization in Drosophila melanogaster. Pyx is expressed in peripheral sensory organs (chordotonal organs), which previously have been implicated in temperature synchronization. Flies deficient for Pyx function fail to synchronize their behaviour to TCs in the lower range (16–20°C), and this deficit can be partially rescued by introducing a wild-type copy of the pyx gene. Synchronization to higher TCs is not affected, demonstrating a specific role for Pyx at lower temperatures. In addition, pyx mutants speed up their clock after being exposed to TCs. Our results identify the first TRP channel involved in temperature synchronization of circadian clocks. PMID:23926145

  2. Numerical simulation of transient temperature profiles for canned apple puree in semi-rigid aluminum based packaging during pasteurization.

    PubMed

    Shafiekhani, Soraya; Zamindar, Nafiseh; Hojatoleslami, Mohammad; Toghraie, Davood

    2016-06-01

    Pasteurization of canned apple puree was simulated for a 3-D geometry in a semi-rigid aluminum based container which was heated from all sides at 378 K. The computational fluid dynamics code Ansys Fluent 14.0 was used and the governing equations for energy, momentum, and continuity were computed using a finite volume method. The food model was assumed to have temperature-dependent properties. To validate the simulation, the apple puree was pasteurized in a water cascading retort. The effect of the mesh structures was studied for the temperature profiles during thermal processing. The experimental temperature in the slowest heating zone in the container was compared with the temperature predicted by the model and the difference was not significant. The study also investigated the impact of head space (water-vapor) on heat transfer. PMID:27478233

  3. Dissociation and ionization equilibria of deuterium fluid over a wide range of temperatures and densities

    SciTech Connect

    Zaghloul, Mofreh R.

    2015-06-15

    We investigate the dissociation and ionization equilibria of deuterium fluid over a wide range of temperatures and densities. The partition functions for molecular and atomic species are evaluated, in a statistical-mechanically consistent way, implementing recent developments in the literature and taking high-density effects into account. A new chemical model (free energy function) is introduced in which the fluid is considered as a mixture of diatomic molecules, atoms, ions, and free electrons. Intensive short range hard core repulsion is taken into account together with partial degeneracy of free electrons and Coulomb interactions among charged particles. Samples of computational results are presented as a set of isotherms for the degree of ionization, dissociated fraction of molecules, pressure, and specific internal energy for a wide range of densities and temperatures. Predictions from the present model calculations show an improved and sensible physical behavior compared to other results in the literature.

  4. Transient Scuffing of Candidate Diesel Engine Materials at Temperatures up to 600oC

    SciTech Connect

    Blau, P.

    2003-06-20

    This milestone report summarizes the general characteristics of scuffing damage to solid surfaces, then describes transient effects on scuffing observed during oscillating sliding wear tests of candidate material pairs for high-temperature diesel engine applications, like waste-gate bushings in exhaust gas recirculation (EGR) systems. It is shown that oxidation and the formation of wear particle layers influence the friction of such components. In the case of metallic materials in cylindrical contacts where there is a generous clearance, debris layers can form which reduce the torque over time. For ceramic combinations, the opposite effect is observed. Here, the accumulation of wear debris leads to an increase in the turning torque. High-temperature transient scuffing behavior is considered in terms of a series of stages in which the composition and morphology of the contact is changing. These changes are used to explain the behavior of 11 material pairs consisting of stainless steels, Ni-based alloys, Co-based alloys, and structural ceramics.

  5. Electrical conductivity and equation of state measurements on planetary fluids at high pressures and temperatures

    SciTech Connect

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

    1987-07-01

    Hugoniot equation-of-state, shock temperature, and electrical conductivity measurements are reported for fluids believed to be the primary constituents of the planets Uranus and Neptune. The equation-of-state results are compared with calculations performed using a statistical mechanical, chemical equilibrium computer code and electrical conductivities are discussed in terms of the recently measured magnetic field of Uranus. 4 refs., 2 figs., 1 tab.

  6. ac-Field-induced fluid pumping in microsystems with asymmetric temperature gradients.

    PubMed

    Holtappels, Moritz; Stubbe, Marco; Gimsa, Jan

    2009-02-01

    We present two different designs of electrohydrodynamic micropumps for microfluidic systems. The micropumps have no movable parts, and their simple design allows for fabrication by microsystems technology. The pumps are operated by ac voltages from 1 to 60 V and were tested with aqueous solutions in the conductivity range of 1-112 mS m(-1). The pump effect is induced by an ac electric field across a fluid medium with an inhomogeneous temperature distribution. It is constant over a wide range of the ac field frequency with a conductivity-dependent drop-off at high frequencies. The temperature-dependent conductivity and permittivity distributions in the fluid induce space charges that interact with the electric field and induce fluid motion. The temperature distribution can be generated either by Joule heating in the medium or by external heating. We present experimental results obtained with two prototypes featuring Joule heating and external heating by a heating filament. Experimental and numerical results are compared with an analytical model. PMID:19391842

  7. The interior working mechanism and temperature characteristics of a fluid based micro-vibration isolator

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Zhao, Shougen; Wu, Dafang; Jing, Xingjian

    2016-01-01

    Micro-vibration isolation is a hot topic in spacecraft vibration control, and fluid based vibration isolators alternatively provide a good and reliable solution to this challenging issue. In this paper, a novel fluid based micro-vibration isolator (FBMVI) is investigated. According to its inherent working principle and deformation pattern, the generation mechanisms of the damping and stiffness characteristics are derived, which are nonlinear functions of the environmental temperature. Then a lumped parameter model which is expressed by the physical design parameters (PDPs) is constructed, and the corresponding performance objective indices (POIs) are also obtained by applying the equivalence of mechanical impedance. Based on the finite element analysis of the internal damping component, a single variable method is further adopted to carry out the parametric study, and the influences of each PDP on the POIs are analyzed in details. Finally, experiments are conducted to identify the variation of fluid bulk modulus with the outside environmental temperature, and to validate the performance of the isolator under different temperature environments. The tested results show great consistence compared with the predicted tendencies of the parametric study. The results of this study can provide a very useful insight into and/or an important guidance for the design and application of this type of FBMVIs in engineering practice.

  8. Transient receptor potential is essential for high temperature tolerance in invasive Bemisia tabaci Middle East Asia minor 1 cryptic species.

    PubMed

    Lü, Zhi-Chuang; Li, Qian; Liu, Wan-Xue; Wan, Fang-Hao

    2014-01-01

    Temperature is an important factor in affecting population dynamics and diffusion distribution of organisms. Alien species can successfully invade and colonize to various temperature environments, and one of important reasons is that alien species have a strong resistance to stress temperature. Recently, researchers have focused on the mechanisms of temperature sensing to determine the sensing and regulation mechanisms of temperature adaptation. The transient receptor potential (TRP) is one of the key components of an organism's temperature perception system. TRP plays important roles in perceiving temperature, such as avoiding high temperature, low temperature and choosing the optimum temperature. To assess high temperature sensation and the heat resistance role of the TRP gene, we used 3' and 5' rapid-amplification of cDNA ends to isolate the full-length cDNA sequence of the TRP gene from Bemisia tabaci (Gennadius) MEAM1 (Middle East Asia Minor 1), examined the mRNA expression profile under various temperature conditions, and identified the heat tolerance function. This is the first study to characterize the TRP gene of invasive B. tabaci MEAM1 (MEAM1 BtTRP). The full-length cDNA of MEAM1 BtTRP was 3871 bp, and the open reading frames of BtTRP was 3501 bp, encoding 1166 amino acids. Additionally, the BtTRP mRNA expression level was significantly increased at 35°C. Furthermore, compared with control treatments, the survival rate of B. tabaci MEAM1 adults was significantly decreased under high temperature stress conditions after feeding with dsRNA BtTRP. Collectively, these results showed that MEAM1 BtTRP is a key element in sensing high temperature and plays an essential role in B. tabaci MEAM1 heat tolerance ability. Our data improved our understanding of the mechanism of temperature sensation in B. tabaci MEAM1 at the molecular level and could contribute to the understanding of the thermal biology of B. tabaci MEAM1 within the context of global climate change

  9. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature

    PubMed Central

    Alawi, Khadija M.; Aubdool, Aisah A.; Liang, Lihuan; Wilde, Elena; Vepa, Abhinav; Psefteli, Maria-Paraskevi; Brain, Susan D.; Keeble, Julie E.

    2015-01-01

    Transient receptor potential vanilloid 1 (TRPV1) is involved in sensory nerve nociceptive signaling. Recently, it has been discovered that TRPV1 receptors also regulate basal body temperature in multiple species from mice to humans. In the present study, we investigated whether TRPV1 modulates basal sympathetic nervous system (SNS) activity. C57BL6/J wild-type (WT) mice and TRPV1 knockout (KO) mice were implanted with radiotelemetry probes for measurement of core body temperature. AMG9810 (50 mg/kg) or vehicle (2% DMSO/5% Tween 80/10 ml/kg saline) was injected intraperitoneally. Adrenoceptor antagonists or vehicle (5 ml/kg saline) was injected subcutaneously. In WT mice, the TRPV1 antagonist, AMG9810, caused significant hyperthermia, associated with increased noradrenaline concentrations in brown adipose tissue. The hyperthermia was significantly attenuated by the β-adrenoceptor antagonist propranolol, the mixed α-/β-adrenoceptor antagonist labetalol, and the α1-adrenoceptor antagonist prazosin. TRPV1 KO mice have a normal basal body temperature, indicative of developmental compensation. d-Amphetamine (potent sympathomimetic) caused hyperthermia in WT mice, which was reduced in TRPV1 KO mice, suggesting a decreased sympathetic drive in KOs. This study provides new evidence that TRPV1 controls thermoregulation upstream of the SNS, providing a potential therapeutic target for sympathetic hyperactivity thermoregulatory disorders.—Alawi, K. M., Aubdool, A. A., Liang, L., Wilde, E., Vepa, A., Psefteli, M.-P., Brain, S. D., Keeble, J. E. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature. PMID:26136480

  10. 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.

  11. 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.

  12. Simulation of a Supercritical Fluid Flow with Large Temperature Difference under the Assumption of Constant Pressure

    NASA Astrophysics Data System (ADS)

    Komurasaki, Satoko

    2015-11-01

    Eruption of geothermally heated water from the hydrothermal vent in deep oceans of depth over 2,000 meters is numerically simulated. The hydrostatic pressure of water is assumed to be over 200 atmospheres, and the temperature of heated water is occasionally more than 300°C. Under these conditions, a part of heated water can be in the supercritical state, and the physical properties can change significantly by the temperature. Particularly, thermal diffusivity at the critical temperature becomes so small, which prevents heat diffusion, and the temperature gradients can become high. Simulation of this kind of fluid flow can be carried out only by using a highly robust scheme. In this paper, a scheme for a highly-unsteady-flow computation is introduced, and a supercritical fluid flow with a large temperature difference is simulated at a constant pressure. In the computation, the compressible Navier-Stokes equations are solved using a method for the incompressible equations under constant pressure. The equations are approximated by the multidirectional finite difference method and KK scheme is used to stabilize the high-accuracy computation. This work was partially supported by Grant-in-Aid for Scientific Research from MEXT/JSPS (26610119).

  13. High temperature fluid-bed heat recovery for aluminum melting furnace

    SciTech Connect

    1982-12-01

    The objective of the study was to establish whether technical problems would be encountered in increasing the inlet temperature of the fluid bed heat exchanger unit at Alcoa above the 1100/sup 0/F target of the current contract. Specifically, the temperature range of up to, and potentially above, 1600/sup 0/F were investigated to establish the benefits of higher temperature, trade offs required, and plans to achieve that technology goal. The benefits are tabulated and are very significant, particularly at the temperature range of 1600 to 1800/sup 0/F. Relative to 1100/sup 0/F the heat recovery is increased by 24 to 29% at 1600 and 1800/sup 0/F respectively.

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

    NASA Astrophysics Data System (ADS)

    Watenphul, Anke; Schmidt, Christian; Jahn, Sandro

    2014-02-01

    Trivalent chromium is generally considered relatively insoluble in aqueous fluids and melts. However, numerous counterexamples in nature indicate Cr(III) mobilization by aqueous fluids during metamorphism or hydrothermal alteration of chromite-bearing rocks, or by pegmatite melts. So far, very little is known about the chromium concentrations and speciation in such fluids. In this study, the solubility of eskolaite (Cr2O3) in 1.6-4.2 m aqueous HCl solutions was determined in situ at elevated pressures up to 1 GPa and temperatures ranging between 400 and 700 °C using synchrotron micro-X-ray fluorescence spectroscopy (μ-XRF). Determined concentrations of dissolved Cr ranged between about 900-18,000 ppm, with the highest concentrations found at 500 °C and 861 MPa. The Cr(III) solubility in aqueous HCl fluids is retrograde in the studied temperature range and increases with pressure. In addition, Cr(III) complexation in these fluids was explored by Raman spectroscopy on a 12.3 mass% HCl fluid in equilibrium with eskolaite at 400 and 600 °C, 0.3-1.6 GPa. All spectra show two prominent Cr-Cl stretching bands at about 275 and 325 cm-1, which display some fine structure, and in some spectra weak bands in the region between 380 and 500 cm-1. The sum of the integrated intensities of the two dominant bands reveals qualitatively the same changes with temperature along an isochore, with pressure at constant temperature, and with the time required for equilibration as the Cr(III) concentrations in the fluid determined by μ-XRF. Complementary ab initio molecular dynamics simulations of a 4 m HCl solution at two different densities (0.8 and 0.97 g/cm3) and temperatures (427 and 727 °C) were performed to investigate the vibrational properties of various(O)y3-x and (O)y(OH)z3-x-z complexes with 3⩽x+z⩽4 and 0⩽y⩽2. Quasi-normal mode analysis reveals that both the tetrahedral symmetric and antisymmetric Cr-Cl stretching vibrations of CrCl4(H2O)0-2- have characteristic

  15. On axial temperature gradients due to large pressure drops in dense fluid chromatography.

    PubMed

    Colgate, Sam O; Berger, Terry A

    2015-03-13

    The effect of energy degradation (Degradation is the creation of net entropy resulting from irreversibility.) accompanying pressure drops across chromatographic columns is examined with regard to explaining axial temperature gradients in both high performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). The observed effects of warming and cooling can be explained equally well in the language of thermodynamics or fluid dynamics. The necessary equivalence of these treatments is reviewed here to show the legitimacy of using whichever one supports the simpler determination of features of interest. The determination of temperature profiles in columns by direct application of the laws of thermodynamics is somewhat simpler than applying them indirectly by solving the Navier-Stokes (NS) equations. Both disciplines show that the preferred strategy for minimizing the reduction in peak quality caused by temperature gradients is to operate columns as nearly adiabatically as possible (i.e. as Joule-Thomson expansions). This useful fact, however, is not widely familiar or appreciated in the chromatography community due to some misunderstanding of the meaning of certain terms and expressions used in these disciplines. In fluid dynamics, the terms "resistive heating" or "frictional heating" have been widely used as synonyms for the dissipation function, Φ, in the NS energy equation. These terms have been widely used by chromatographers as well, but often misinterpreted as due to friction between the mobile phase and the column packing, when in fact Φ describes the increase in entropy of the system (dissipation, ∫TdSuniv>0) due to the irreversible decompression of the mobile phase. Two distinctly different contributions to the irreversibility are identified; (1) ΔSext, viscous dissipation of work done by the external surroundings driving the flow (the pump) contributing to its warming, and (2) ΔSint, entropy change accompanying decompression of

  16. Numerical Analysis of Effect of Backplate Diffusivity on the Transient Temperature in Friction Stir Welding

    NASA Astrophysics Data System (ADS)

    Zhang, Zhihan; Li, Wenya; Li, Jinglong; Chao, Y. J.

    2013-09-01

    It is still not clearly known as to what extent the temperature field of friction stir welding joint is influenced by backplate diffusivity owing to the limitation of temperature measuring points. In the present study, therefore, the effect of backplate diffusivity on the temperature field of the workpiece was systematically investigated based on the numerical analysis. Simulated results show that the backplate diffusivity has a significant influence on not only the peak temperature but the final temperature distribution. More heat is dissipated by using a high thermal conductivity backplate during FSW. With increasing the backplate diffusivity, the peak temperature decreases gradually and the average cooling rate increases first and then slightly decreases. In addition, the time spent above 195 °C presents a nearly linear decrease with increasing the backplate diffusivity. Moreover, the width of temperature region higher than 195 °C in the transverse direction is remarkably diminished by using the backplate of a high conductivity, and changes little during the entire process.

  17. Two-fluid Hydrodynamic Model for Fluid-Flow Simulation in Fluid-Solids Systems

    Energy Science and Technology Software Center (ESTSC)

    1994-06-20

    FLUFIX is a two-dimensional , transient, Eulerian, and finite-difference program, based on a two-fluid hydrodynamic model, for fluid flow simulation in fluid-solids systems. The software is written in a modular form using the Implicit Multi-Field (IMF) numerical technique. Quantities computed are the spatial distribution of solids loading, gas and solids velocities, pressure, and temperatures. Predicted are bubble formation, bed frequencies, and solids recirculation. Applications include bubbling and circulating atmospheric and pressurized fluidized bed reactors, combustors,more » gasifiers, and FCC (Fluid Catalytic Cracker) reactors.« less

  18. Coherent Raman scattering in high-pressure/high-temperature fluids: An overview

    SciTech Connect

    Schmidt, S.C.; Moore, D.S.

    1990-01-01

    The present understanding of high-pressure/high-temperature dense-fluid behavior is derived almost exclusively from hydrodynamic and thermodynamic measurements. Such results average over the microscopic aspects of the materials and are, therefore, insufficient for a complete understanding of fluid behavior. At the present, dense-fluid models can be verified only to the extend that they agree with the macroscopic measurements. Recently, using stimulated Raman scattering, Raman induced Kerr effect scattering, and coherent anti-Stokes Raman scattering, we have been able to probe some of the microscopic phenomenology of these dense fluids. In this paper, we discuss primarily the use of CARS in conjunction with a two-stage light-gas gun to obtain vibrational spectra of shock-compressed liquid N{sub 2}, O{sub 2}, CO, their mixtures, CH{sub 3}NO{sub 2}, and N{sub 2}O. These experimental spectra are compared to synthetic spectra calculated using a semiclassical model for CARS intensities and best fit vibrational frequencies, peak Raman susceptibilities, and Raman linewidths. For O{sub 2}, the possibility of resonance enhancement from collision-induced absorption is addressed. Shifts in the vibrational frequencies reflect the influence of increased density and temperature on the intramolecular motion. The derived parameters suggest thermal equilibrium of the vibrational levels is established less than a few nanoseconds after shock passage. Vibrational temperatures are obtained that agree with those derived from equation-of-state calculations. Measured linewidths suggest that vibrational dephasing times have decreased to subpicosecond values at the highest shock pressures.

  19. Temperature and Redox Effect on Mineral Colonization in Juan de Fuca Ridge Flank Subsurface Crustal Fluids

    PubMed Central

    Baquiran, Jean-Paul M.; Ramírez, Gustavo A.; Haddad, Amanda G.; Toner, Brandy M.; Hulme, Samuel; Wheat, Charles G.; Edwards, Katrina J.; Orcutt, Beth N.

    2016-01-01

    To examine microbe-mineral interactions in subsurface oceanic crust, we evaluated microbial colonization on crustal minerals that were incubated in borehole fluids for 1 year at the seafloor wellhead of a crustal borehole observatory (IODP Hole U1301A, Juan de Fuca Ridge flank) as compared to an experiment that was not exposed to subsurface crustal fluids (at nearby IODP Hole U1301B). In comparison to previous studies at these same sites, this approach allowed assessment of the effects of temperature, fluid chemistry, and/or mineralogy on colonization patterns of different mineral substrates, and an opportunity to verify the approach of deploying colonization experiments at an observatory wellhead at the seafloor instead of within the borehole. The Hole U1301B deployment did not have biofilm growth, based on microscopy and DNA extraction, thereby confirming the integrity of the colonization design against bottom seawater intrusion. In contrast, the Hole U1301A deployment supported biofilms dominated by Epsilonproteobacteria (43.5% of 370 16S rRNA gene clone sequences) and Gammaproteobacteria (29.3%). Sequence analysis revealed overlap in microbial communities between different minerals incubated at the Hole U1301A wellhead, indicating that mineralogy did not separate biofilm structure within the 1-year colonization experiment. Differences in the Hole U1301A wellhead biofilm community composition relative to previous studies from within the borehole using similar mineral substrates suggest that temperature and the diffusion of dissolved oxygen through plastic components influenced the mineral colonization experiments positioned at the wellhead. This highlights the capacity of low abundance crustal fluid taxa to rapidly establish communities on diverse mineral substrates under changing environmental conditions such as from temperature and oxygen. PMID:27064928

  20. Temperature and Redox Effect on Mineral Colonization in Juan de Fuca Ridge Flank Subsurface Crustal Fluids.

    PubMed

    Baquiran, Jean-Paul M; Ramírez, Gustavo A; Haddad, Amanda G; Toner, Brandy M; Hulme, Samuel; Wheat, Charles G; Edwards, Katrina J; Orcutt, Beth N

    2016-01-01

    To examine microbe-mineral interactions in subsurface oceanic crust, we evaluated microbial colonization on crustal minerals that were incubated in borehole fluids for 1 year at the seafloor wellhead of a crustal borehole observatory (IODP Hole U1301A, Juan de Fuca Ridge flank) as compared to an experiment that was not exposed to subsurface crustal fluids (at nearby IODP Hole U1301B). In comparison to previous studies at these same sites, this approach allowed assessment of the effects of temperature, fluid chemistry, and/or mineralogy on colonization patterns of different mineral substrates, and an opportunity to verify the approach of deploying colonization experiments at an observatory wellhead at the seafloor instead of within the borehole. The Hole U1301B deployment did not have biofilm growth, based on microscopy and DNA extraction, thereby confirming the integrity of the colonization design against bottom seawater intrusion. In contrast, the Hole U1301A deployment supported biofilms dominated by Epsilonproteobacteria (43.5% of 370 16S rRNA gene clone sequences) and Gammaproteobacteria (29.3%). Sequence analysis revealed overlap in microbial communities between different minerals incubated at the Hole U1301A wellhead, indicating that mineralogy did not separate biofilm structure within the 1-year colonization experiment. Differences in the Hole U1301A wellhead biofilm community composition relative to previous studies from within the borehole using similar mineral substrates suggest that temperature and the diffusion of dissolved oxygen through plastic components influenced the mineral colonization experiments positioned at the wellhead. This highlights the capacity of low abundance crustal fluid taxa to rapidly establish communities on diverse mineral substrates under changing environmental conditions such as from temperature and oxygen. PMID:27064928

  1. Effect of temperature on steady shear magnetorheology of CoNi microcluster-based MR fluids

    NASA Astrophysics Data System (ADS)

    Arief, Injamamul; Sahoo, Rasmita; Mukhopadhyay, P. K.

    2016-08-01

    We present the study of magnetorheological properties of magnetic fluids containing Co-rich CoNi microcluster that have been measured as a function of both magnetic field and temperature. Co-rich microclusters were synthesized by conventional homogeneous nucleation in liquid polyol. Morphological characterization using FESEM revealed the average diameter of microclusters as 450 nm. Crystal structure and room temperature magnetization measurements were performed by powder XRD and vibrating sample magnetometry. Two MR samples of different particle volume fractions were prepared. Temperature-dependent steady shear MR characterizations for both the samples in the range of 25-55 °C demonstrated systematic decline of MR parameters with increasing temperatures. The temperature-induced thinning of shear stress and viscosity was explained in terms of change in effective volume fraction. To analyze the measured variation in MR response with increasing temperature, suitable temperature-sensitive scaling parameters were also constructed. Finally to generalize the trend, rheological master curves were constructed by using time-temperature-field superposition method.

  2. Low-temperature, selective catalytic deoxygenation of vegetable oil in supercritical fluid media.

    PubMed

    Kim, Seok Ki; Lee, Hong-Shik; Hong, Moon Hyun; Lim, Jong Sung; Kim, Jaehoon

    2014-02-01

    The effects of supercritical fluids on the production of renewable diesel-range hydrocarbons from natural triglycerides were investigated. Various supercritical fluids, which included CO2 (scCO2 ), propane (scC3 H8 ) and n-hexane (scC6 H14 ), were introduced with H2 and soybean oil into a fixed-bed reactor that contained pre-activated CoMo/γ-Al2 O3 . Among these supercritical fluids, scC3 H8 and scC6 H14 efficiently allowed the reduction of the reaction temperature by as much as 50 °C as a result of facilitated heat and mass transfer and afforded similar yields to reactions in the absence of supercritical fluids. The compositional analyses of the gas and liquid products indicated that the addition of scC3 H8 during the hydrotreatment of soybean oil promoted specific deoxygenation pathways, decarbonylation and decarboxylation, which consumed less H2 than the hydrodeoxygenation pathway. As a result, the quantity of H2 required to obtain a high yield of diesel-range hydrocarbons could be reduced to 57 % if scC3 H8 was used. As decarboxylation and decarbonylation are mildly endothermic reactions, the reduced heat transfer resistance in scC3 H8 may drive the deoxygenation reaction to thermodynamically favourable pathways. PMID:24339322

  3. A split band-Cholesky equation solving strategy for finite element analysis of transient field problems. [in fluid mechanics

    NASA Technical Reports Server (NTRS)

    Cooke, C. H.

    1978-01-01

    The paper describes the split-Cholesky strategy for banded matrices arising from the large systems of equations in certain fluid mechanics problems. The basic idea is that for a banded matrix the computation can be carried out in pieces, with only a small portion of the matrix residing in core. Mesh considerations are discussed by demonstrating the manner in which the assembly of finite element equations proceeds for linear trial functions on a triangular mesh. The FORTRAN code which implements the out-of-core decomposition strategy for banded symmetric positive definite matrices (mass matrices) of a coupled initial value problem is given.

  4. Two-fluid temperature-dependent relativistic waves in magnetized streaming pair plasmas.

    PubMed

    Soto-Chavez, A R; Mahajan, S M; Hazeltine, R D

    2010-02-01

    A relativistic two-fluid temperature-dependent approach for a streaming magnetized pair plasma is considered. Such a scenario corresponds to secondary plasmas created at the polar caps of pulsar magnetospheres. In the model the generalized vorticity rather than the magnetic field is frozen into the fluid. For parallel propagation four transverse modes are found. Two are electromagnetic plasma modes which at high temperature become light waves. The remaining two are Alfvénic modes split into a fast and slow mode. The slow mode is cyclotron two-stream unstable at large wavelengths and is always subluminous. We find that the instability cannot be suppressed by temperature effects in the limit of large (finite) magnetic field. The fast Alfvén mode can be superluminous only at large wavelengths, however it is always subluminous at high temperatures. In this incompressible approximation only the ordinary mode is present for perpendicular propagation. For oblique propagation the dispersion relation is studied for finite and large strong magnetic fields and the results are qualitatively described. PMID:20365661

  5. Phenylnaphthalene as a Heat Transfer Fluid for Concentrating Solar Power: High-Temperature Static Experiments

    SciTech Connect

    Bell, Jason R; Joseph III, Robert Anthony; McFarlane, Joanna; Qualls, A L

    2012-05-01

    Concentrating solar power (CSP) may be an alternative to generating electricity from fossil fuels; however, greater thermodynamic efficiency is needed to improve the economics of CSP operation. One way of achieving improved efficiency is to operate the CSP loop at higher temperatures than the current maximum of about 400 C. ORNL has been investigating a synthetic polyaromatic oil for use in a trough type CSP collector, to temperatures up to 500 C. The oil was chosen because of its thermal stability and calculated low vapor and critical pressures. The oil has been synthesized using a Suzuki coupling mechanism and has been tested in static heating experiments. Analysis has been conducted on the oil after heating and suggests that there may be some isomerization taking place at 450 C, but the fluid appears to remain stable above that temperature. Tests were conducted over one week and further tests are planned to investigate stabilities after heating for months and in flow configurations. Thermochemical data and thermophysical predictions indicate that substituted polyaromatic hydrocarbons may be useful for applications that run at higher temperatures than possible with commercial fluids such as Therminol-VP1.

  6. Unsteady magnetohydrodynamic free convection flow of a second grade fluid in a porous medium with ramped wall temperature.

    PubMed

    Samiulhaq; Ahmad, Sohail; Vieru, Dumitru; Khan, Ilyas; Shafie, Sharidan

    2014-01-01

    Magnetic field influence on unsteady free convection flow of a second grade fluid near an infinite vertical flat plate with ramped wall temperature embedded in a porous medium is studied. It has been observed that magnitude of velocity as well as skin friction in case of ramped temperature is quite less than the isothermal temperature. Some special cases namely: (i) second grade fluid in the absence of magnetic field and porous medium and (ii) Newtonian fluid in the presence of magnetic field and porous medium, performing the same motion are obtained. Finally, the influence of various parameters is graphically shown. PMID:24785147

  7. Unsteady Magnetohydrodynamic Free Convection Flow of a Second Grade Fluid in a Porous Medium with Ramped Wall Temperature

    PubMed Central

    Samiulhaq; Ahmad, Sohail; Vieru, Dumitru; Khan, Ilyas; Shafie, Sharidan

    2014-01-01

    Magnetic field influence on unsteady free convection flow of a second grade fluid near an infinite vertical flat plate with ramped wall temperature embedded in a porous medium is studied. It has been observed that magnitude of velocity as well as skin friction in case of ramped temperature is quite less than the isothermal temperature. Some special cases namely: (i) second grade fluid in the absence of magnetic field and porous medium and (ii) Newtonian fluid in the presence of magnetic field and porous medium, performing the same motion are obtained. Finally, the influence of various parameters is graphically shown. PMID:24785147

  8. Calculation procedure for transient heat transfer to a cooled plate in a heated stream whose temperature varies arbitrarily with time. [turbine blades

    NASA Technical Reports Server (NTRS)

    Sucec, J.

    1975-01-01

    Solutions for the surface temperature and surface heat flux are found for laminar, constant property, slug flow over a plate convectively cooled from below, when the temperature of the fluid over the plate varies arbitrarily with time at the plate leading edge. A simple technique is presented for handling arbitrary fluid temperature variation with time by approximating it by a sequence of ramps or steps for which exact analytical solutions are available.

  9. Fluid chemistry studies of three low- to moderate-temperature geothermal resource areas in Nevada

    SciTech Connect

    Koening, B.A.; Trexler, D.T.; Flynn, T.

    1980-09-01

    By analyzing thermal and non-thermal fluids from three widely separated areas in Nevada useful information on the source and flow paths of the waters was obtained. Major cation and anion compositions show variations which can usually be related to specific locations within the study region. However, this in not always valid; for example, one area studied which is very limited in areal extent shows only minor differences in major ion composition when comparing hot and cold waters. Silica content of the fluids was determined to have no simple relationship to temperature: the highest contents occurring in waters with temperatures significantly below the maximum in each area. Trace element analyses proved to be of limited benefit to our general study but may be helpful in defining recharge or chemical processes occurring at a specific site where a known source or sink for the elements can be identified. Stable isotope analysis for oxygen and hydrogen when combined with the constraints imposed by a knowledge of major dissolved constituent composition permit meaningful distinctions to be made between areas and different locations within a single region. These distinctions are readily apparent for the Darrough's Hot Springs area within the Big Smoky Valley which exhibits oxygen isotopic shifts of 7 to 9 per mil combined with a notably different major ion composition when compared to other thermal fluids in the study area.

  10. Reduced-Temperature Transient-Liquid-Phase Bonding of AluminaUsing a Ag-Cu-Based Brazing Alloy

    SciTech Connect

    Hong, Sung Moo; Glaeser, Andreas M.

    2005-12-19

    The mechanical properties and microstructural evolution ofmetal-ceramic bonds produced using a transient liquid phase (TLP) aredescribed. Alumina (Al2O3) was joined at 500 degrees C, 600 degrees C,and 700 degrees C using a multilayer In/Cusil-ABA (R) (commercialcopper-silver eutectic brazing alloy)/In interlayer. The introduction ofthin In cladding layers allows the system to bond at much lowertemperatures than those typically used for brazing with Cusil-ABA (R),thereby protecting temperature-sensitive components. After chemicalhomogenization, the interlayers retain an operating temperature rangesimilar to that of the brazed joints. TLP bonds made at 500 degrees C,600 degrees C, and 700 degrees C with holding times ranging from as lowas 1.5 h to 24 h had average fracture strengths above 220 MPa. Theeffects of bonding temperature and time on fracture strength aredescribed. Preliminary analysis of the interlayers shows that the Ag-Inor Cu-In intermetallic phases do not form. Considerations unique tosystems with two-phase core layers are discussed. Experiments usingsingle-crystal sapphire indicate rapid formation of a reaction layer at700 degrees C, suggesting the possibility of making strong bonds usinglower temperatures and/or shorter processing times.

  11. Pharmacology of modality-specific transient receptor potential vanilloid-1 antagonists that do not alter body temperature.

    PubMed

    Reilly, Regina M; McDonald, Heath A; Puttfarcken, Pamela S; Joshi, Shailen K; Lewis, LaGeisha; Pai, Madhavi; Franklin, Pamela H; Segreti, Jason A; Neelands, Torben R; Han, Ping; Chen, Jun; Mantyh, Patrick W; Ghilardi, Joseph R; Turner, Teresa M; Voight, Eric A; Daanen, Jerome F; Schmidt, Robert G; Gomtsyan, Arthur; Kort, Michael E; Faltynek, Connie R; Kym, Philip R

    2012-08-01

    The transient receptor potential vanilloid-1 (TRPV1) channel is involved in the development and maintenance of pain and participates in the regulation of temperature. The channel is activated by diverse agents, including capsaicin, noxious heat (≥ 43°C), acidic pH (< 6), and endogenous lipids including N-arachidonoyl dopamine (NADA). Antagonists that block all modes of TRPV1 activation elicit hyperthermia. To identify efficacious TRPV1 antagonists that do not affect temperature antagonists representing multiple TRPV1 pharmacophores were evaluated at recombinant rat and human TRPV1 channels with Ca(2+) flux assays, and two classes of antagonists were identified based on their differential ability to inhibit acid activation. Although both classes of antagonists completely blocked capsaicin- and NADA-induced activation of TRPV1, select compounds only partially inhibited activation of the channel by protons. Electrophysiology and calcitonin gene-related peptide release studies confirmed the differential pharmacology of these antagonists at native TRPV1 channels in the rat. Comparison of the in vitro pharmacological properties of these TRPV1 antagonists with their in vivo effects on core body temperature confirms and expands earlier observations that acid-sparing TRPV1 antagonists do not significantly increase core body temperature. Although both classes of compounds elicit equivalent analgesia in a rat model of knee joint pain, the acid-sparing antagonist tested is not effective in a mouse model of bone cancer pain. PMID:22570364

  12. Ceres water regime: surface temperature, water sublimation and transient exo(atmo)sphere

    NASA Astrophysics Data System (ADS)

    Formisano, M.; De Sanctis, M. C.; Magni, G.; Federico, C.; Capria, M. T.

    2016-01-01

    Recent observations of water emission around Ceres suggest the presence of an ice layer on or beneath the surface of this asteroid. Several mechanisms have been suggested to explain these plumes, among which cometary-like sublimation seems to be plausible, since there is a correlation between the magnitude of the emission and the change in the heliocentric distance along the orbit. In this work, we applied a comet sublimation model to study the plausible scenarios that match with Herschel observations of the water flux (1026 molecules s-1). Each scenario is characterized by a well-defined set of physical and orbital parameters. Moreover, a study of the dynamic evolution of the H2O plume has been performed, showing that an optically thin transient atmospheric envelope, with a typical timescale of some tens of days, can be maintained by the H2O surface emission. Our simulations could be useful theoretical support for the Dawn NASA mission by giving a better understanding of the physical conditions for water sublimation and ice stability.

  13. A perfectly matched layer formulation for modeling transient wave propagation in an unbounded fluid-solid medium.

    PubMed

    Assi, Hisham; Cobbold, Richard S C

    2016-04-01

    Wave propagation in an infinite medium can be numerically simulated by surrounding a finite region by a perfectly matched layer (PML). When the medium is heterogeneous consisting of both solids and liquids, careful consideration is needed in specifying the properties of the PML especially because parts of it lie at the solid-fluid interface. While such a situation could arise in many important fields including marine seismology, where water is in contact with earth, and in biomedical ultrasound, where soft tissue is in contact with bone, no PML formulation exists to appropriately model such coupled problems. Here, a second-order time-domain PML formulation for fluid-solid heterogeneous media in two dimensions that satisfies the interface coupling boundary condition throughout the computational domain is presented. Numerical results are given to establish the applicability and accuracy of such a PML formulation in discrete settings without causing stability issues, spurious reflections, or any other problems. In particular, the effectiveness of the PML in absorbing all kinds of bulk waves, as well as surface and evanescent waves, is studied. PMID:27106301

  14. Gas temperature in transient CO2 plasma measured by Raman scattering

    NASA Astrophysics Data System (ADS)

    Brehmer, F.; Welzel, S.; Klarenaar, B. L. M.; van der Meiden, H. J.; van de Sanden, M. C. M.; Engeln, R.

    2015-04-01

    Rotational Raman scattering on the vibrational ground state of CO2 was performed to determine the gas temperature in narrow-gap dielectric barrier discharges (DBDs). The Raman spectrometer was equipped with a straightforward spectral filtering to mask ca. 30 cm-1 (0.85 nm) centered around the excitation wavelength of 532 nm. Linearisation of the observed transitions (J = 18-42) was applied to retrieve gas temperatures in discharge gaps of 1 mm. The DBD was operated in pure CO2 at atmospheric pressure and non-negligible gas heating of about 160 K was observed at 33 W injected power. Based on a simplified energy balance the gas temperature measurements were extrapolated to a broad range of injected plasma power values (0-60 W).

  15. New fluid model for the turbulent transport due to the ion temperature gradient

    SciTech Connect

    Kim, C. ); Horton, W. ); Hamaguchi, S. )

    1993-05-01

    A new set of equations appropriate for the study of the turbulence, due to the ion temperature gradient in the slab in the fluid description, is proposed. This model is similar to many existing models including the one used in the work of Hamaguchi and Horton (HH) [S. Hamaguchi and W. Horton, Phys. Fluids B [bold 2], 1834 (1990)]. The main difference is that in this model the ion diamagnetic drift contributes to the kinetic energy in the energy balance relation. It is achieved through more complete analysis for the polarization drift due to the finite-Larmor-radius effects. The linear growth rate in the model is found to be smaller and the numerical results show that the heat transport is smaller by an order of magnitude when compared to HH.

  16. Microstructural study of transient liquid phase bonded DD98 and K465 superalloys at high temperature

    SciTech Connect

    Liu Jide Jin Tao; Zhao Nairen; Wang Zhihui; Sun Xiaofeng; Guan Hengrong; Hu Zhuangqi

    2011-05-15

    Microstructure of a transient liquid phase (TLP) bonded joint between single crystal DD98 and polycrystalline K465 superalloys was investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. After bonding at 1190 deg. C for 2 h, many phases formed in the centerline of the bonding zone due to an incompletely solidified liquid interlayer. There are script-like, tree-like and blocky compounds besides solid solution {gamma} phase in this region. The script-like phase is CrB boride that is rich in Cr, the tree-like compound rich in Ni is M{sub 23}B{sub 6} with FCC structure, and the blocky phase enriched in Ti, Ta, and Nb, is MC carbide that resulted from the interdiffusion of C atoms between dissimilar base metals. After TLP bonding, many blocky and fine M{sub 6}C particles rich in Cr and W appeared in the diffusion zone of the K465 side. A number of blocky and platelet M{sub 3}B{sub 2} borides rich in W, Cr and Mo precipitated in the diffusion zone of the DD98 side. - Research Highlights: {yields} DD98 and K465 alloy was TLP bonded. {yields} The microstructure changes of different parts were studied. {yields} CrB, M{sub 23}B{sub 6} and MC formed in the bonding zone. {yields} M{sub 6}C appeared in diffusion zone of K465 side and M{sub 3}B{sub 2} existed in diffusion zone of DD98 side.

  17. Water geochemistry of the Lucero Uplift, New Mexico: geothermal investigation of low-temperature mineralized fluids

    SciTech Connect

    Goff, F.; McCormick, T.; Gardner, J.N.; Trujillo, P.E.; Counce, D.; Vidale, R.; Charles, R.

    1983-04-01

    A detailed geochemical investigation of 27 waters of the Lucero uplift, central New Mexico, was performed to determine if the fluids originate from a high-temperature geothermal system along the Rio Grande rift. Two types of mineralized water issue from the Lucero region: a relatively saline (high-Cl, high-SO/sub 4/) type and a relatively dilute (low-Cl, high-SO/sub 4/) type. Emergence temperatures of both types range from 12 to 26/sup 0/C. Chemical data and thermodynamic and geothermometer calculations all indicate that both water types are in equilibrium with carbonate and evaporite minerals found in local Colorado Plateau rocks at surface temperatures or slightly higher. Stable isotope data do not indicate high-temperature rock-water interaction. Although evidence is seen for mixing between mineralized waters and dilute surface waters, no evidence for mixing of a deep hot fluid and surface waters is seen. Dilute mineral waters, which issue from a large area of Chinle Formation on the west side of the Lucero uplift, may be useful for low-temperature geothermal applications with appropriate design of equipment. Saline mineral waters, which leak from a zone of faulted and folded rocks along the Comanche fault zone, do not appear to have much, if any, geothermal potential due to their low-temperature, restricted distribution, and high concentration of dissolved solids. No evidence that saline mineral waters are associated with Quaternary faults of the Rio Grande rift or Quaternary basaltic volcanism within the immediate area is seen.

  18. EFFECT OF TRANSIENT TEMPERATURE CHANGE ON SUCROSE METABOLISM IN SUGARCANE INTERNODES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It was previously observed that a decrease in total soluble solids concentration in sugarcane (Saccharum sp. hybrids) juice was proportional to the magnitude of the change of temperature during the week prior to harvest (Eggleston and Vinyard, 1999. J. Am. Soc. Sugar Cane Technol. 19:62-63). I teste...

  19. A computational model for transient temperature rise in a dye laser gain medium pumped by a copper vapor laser

    NASA Astrophysics Data System (ADS)

    Rawat, V. S.; Gantayet, L. M.; Sridhar, G.; Singh, S.

    2014-02-01

    Spectrally stable dye lasers play an important role in techniques based on high resolution spectroscopy and atomic spectroscopy. The spectral purity of a dye laser is affected when the pump power to it is increased beyond the threshold. When the pump power is increased beyond the threshold, two mode oscillations occur which decrease the spectral purity of the dye laser. The effect of higher pump pulse energies on transient thermal effects has been studied using a computational fluid dynamics (CFD) model and the disturbances to the laser cavity have been studied using commercially available ray tracing software. The change in the cavity length was determined from the CFD model for several dye concentrations and pump powers. The results of the CFD model have been verified by published results and experimental results from our system. Our study shows that in the longitudinally pumped single mode laser change in the cavity length is a more dominant disturbance than thermal blooming. Our model is useful for the design of the dye cell.

  20. 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

  1. Transient two-phase flow of cryogenic fluid in a vertical transfer line during the cooldown process

    NASA Astrophysics Data System (ADS)

    Hedayatpour, Ali

    1990-08-01

    The analytical and numerical modeling for prediction of the thermofluid parameters of the cool down process of a vertical tube carrying cryogenic liquid are presented. Formulation of the problem is based on the flow patterns observed in the experimental studies. In this model, the flow field consists of four distinct regions of fully liquid, inverted annular film boiling, dispersed flow film boiling, and fully vapor. For the fully liquid and fully vapor regions, the 1-D two-fluid model conservation equations are applied. In addition, a 1-D energy equation is formulated to determine the tube wall history. The numerical approximations are based on the finite difference technique. Calculation for inverted annular flow are based on a semi-implicit model while computations for the wall, fully liquid, and dispersed flow regions are performed explicitly. Comparison of calculated results with experimental data for water and liquid nitrogen are presented.

  2. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature.

    PubMed

    Alawi, Khadija M; Aubdool, Aisah A; Liang, Lihuan; Wilde, Elena; Vepa, Abhinav; Psefteli, Maria-Paraskevi; Brain, Susan D; Keeble, Julie E

    2015-10-01

    Transient receptor potential vanilloid 1 (TRPV1) is involved in sensory nerve nociceptive signaling. Recently, it has been discovered that TRPV1 receptors also regulate basal body temperature in multiple species from mice to humans. In the present study, we investigated whether TRPV1 modulates basal sympathetic nervous system (SNS) activity. C57BL6/J wild-type (WT) mice and TRPV1 knockout (KO) mice were implanted with radiotelemetry probes for measurement of core body temperature. AMG9810 (50 mg/kg) or vehicle (2% DMSO/5% Tween 80/10 ml/kg saline) was injected intraperitoneally. Adrenoceptor antagonists or vehicle (5 ml/kg saline) was injected subcutaneously. In WT mice, the TRPV1 antagonist, AMG9810, caused significant hyperthermia, associated with increased noradrenaline concentrations in brown adipose tissue. The hyperthermia was significantly attenuated by the β-adrenoceptor antagonist propranolol, the mixed α-/β-adrenoceptor antagonist labetalol, and the α1-adrenoceptor antagonist prazosin. TRPV1 KO mice have a normal basal body temperature, indicative of developmental compensation. d-Amphetamine (potent sympathomimetic) caused hyperthermia in WT mice, which was reduced in TRPV1 KO mice, suggesting a decreased sympathetic drive in KOs. This study provides new evidence that TRPV1 controls thermoregulation upstream of the SNS, providing a potential therapeutic target for sympathetic hyperactivity thermoregulatory disorders. PMID:26136480

  3. The role of fluid temperature and form on endurance performance in the heat.

    PubMed

    Tan, P M S; Lee, J K W

    2015-06-01

    Exercising in the heat often results in an excessive increase in body core temperature, which can be detrimental to health and endurance performance. Research in recent years has shifted toward the optimum temperature at which drinks should be ingested. The ingestion of cold drinks can reduce body core temperature before exercise but less so during exercise. Temperature of drinks does not seem to have an effect on the rate of gastric emptying and intestinal absorption. Manipulating the specific heat capacity of a solution can further induce a greater heat sink. Ingestion of ice slurry exploits the additional energy required to convert the solution from ice to water (enthalpy of fusion). Body core temperature is occasionally observed to be higher at the point of exhaustion with the ingestion of ice slurry. There is growing evidence to suggest that ingesting ice slurry is an effective and practical strategy to prevent excessive rise of body core temperature and improve endurance performance. This information is especially important when only a fixed amount of fluid is allowed to be carried, often seen in some ultra-endurance events and military operations. Future studies should evaluate the efficacy of ice slurry in various exercise and environmental conditions. PMID:25943655

  4. On the temperature dependence of the ac susceptibility of Fe 3O 4 magnetic fluids

    NASA Astrophysics Data System (ADS)

    Abu-Aljarayesh, I.; Al-Rawi, A.; Abu-Safia, H.

    1993-02-01

    The temperature dependence of the frequency-dependent magnetic susceptibility has been measured for Fe 3O 4 magnetic fluids with Isopar-M as a liquid carrier. The temperature range was 80 K ≤ T ≤ 300 K, and the volume fractions ɛ ranged from 0.004 to 0.062. With increasing temperature the in-phase magnetic susceptibility χ' increased from its initial value to a maximum at a temperature TB, then decreased monotonically until around the melting point of the liquid carrier, Tm ≈ 200 K. For T ≤ Tm, χ' increased rapidly to a second maximum at T = TB1. This behaviour was qualitatively similar for all studied samples. For the sample with ɛ = 0.047, χ' decreased with increasing frequency at all temperatures. When a static magnetic field was applied, a reduction in χ' was also observed. The effects of interparticle interactions on the static initial susceptibility χ i, are discussed. Analysis of the data yields information about the effective anisotropy energy, the median magnetic diameter, and relaxation times. The distribution of blocking temperature was calculated from the superparamagnetic blocking model of Wohlfarth. The results are further analysed and discussed within the framework of Lundgren model of spin glasses.

  5. Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling

    SciTech Connect

    Mukhopadhyay, S.; Tsang, Y.; Finsterle, S.

    2009-01-15

    A simple conceptual model has been recently developed for analyzing pressure and temperature data from flowing fluid temperature logging (FFTL) in unsaturated fractured rock. Using this conceptual model, we developed an analytical solution for FFTL pressure response, and a semianalytical solution for FFTL temperature response. We also proposed a method for estimating fracture permeability from FFTL temperature data. The conceptual model was based on some simplifying assumptions, particularly that a single-phase airflow model was used. In this paper, we develop a more comprehensive numerical model of multiphase flow and heat transfer associated with FFTL. Using this numerical model, we perform a number of forward simulations to determine the parameters that have the strongest influence on the pressure and temperature response from FFTL. We then use the iTOUGH2 optimization code to estimate these most sensitive parameters through inverse modeling and to quantify the uncertainties associated with these estimated parameters. We conclude that FFTL can be utilized to determine permeability, porosity, and thermal conductivity of the fracture rock. Two other parameters, which are not properties of the fractured rock, have strong influence on FFTL response. These are pressure and temperature in the borehole that were at equilibrium with the fractured rock formation at the beginning of FFTL. We illustrate how these parameters can also be estimated from FFTL data.

  6. Thin film flow in MHD third grade fluid on a vertical belt with temperature dependent viscosity.

    PubMed

    Gul, Taza; Islam, Saed; Shah, Rehan Ali; Khan, Ilyas; Shafie, Sharidan

    2014-01-01

    In this work, we have carried out the influence of temperature dependent viscosity on thin film flow of a magnetohydrodynamic (MHD) third grade fluid past a vertical belt. The governing coupled non-linear differential equations with appropriate boundary conditions are solved analytically by using Adomian Decomposition Method (ADM). In order to make comparison, the governing problem has also been solved by using Optimal Homotopy Asymptotic Method (OHAM). The physical characteristics of the problem have been well discussed in graphs for several parameter of interest. PMID:24949988

  7. Fluid simulation of tokamak ion temperature gradient turbulence with zonal flow closure model

    NASA Astrophysics Data System (ADS)

    Yamagishi, Osamu; Sugama, Hideo

    2016-03-01

    Nonlinear fluid simulation of turbulence driven by ion temperature gradient modes in the tokamak fluxtube configuration is performed by combining two different closure models. One model is a gyrofluid model by Beer and Hammett [Phys. Plasmas 3, 4046 (1996)], and the other is a closure model to reproduce the kinetic zonal flow response [Sugama et al., Phys. Plasmas 14, 022502 (2007)]. By including the zonal flow closure, generation of zonal flows, significant reduction in energy transport, reproduction of the gyrokinetic transport level, and nonlinear upshift on the critical value of gradient scale length are observed.

  8. Thin Film Flow in MHD Third Grade Fluid on a Vertical Belt with Temperature Dependent Viscosity

    PubMed Central

    Gul, Taza; Islam, Saed; Shah, Rehan Ali; Khan, Ilyas; Shafie, Sharidan

    2014-01-01

    In this work, we have carried out the influence of temperature dependent viscosity on thin film flow of a magnetohydrodynamic (MHD) third grade fluid past a vertical belt. The governing coupled non-linear differential equations with appropriate boundary conditions are solved analytically by using Adomian Decomposition Method (ADM). In order to make comparison, the governing problem has also been solved by using Optimal Homotopy Asymptotic Method (OHAM). The physical characteristics of the problem have been well discussed in graphs for several parameter of interest. PMID:24949988

  9. High-resolution distributed temperature sensing: a new tool to study the space-time dynamics of transient cold-air pools in the weak-wind stable boundary layer

    NASA Astrophysics Data System (ADS)

    Thomas, C. K.; Selker, J. S.; Zeeman, M. J.

    2011-12-01

    We present a novel approach to observing the two-dimensional thermal structure of atmospheric near-surface turbulent and non-turbulent flows by measuring air temperatures in a vertical plane at a high resolution (0.25 m, every approximately 2 s) using distributed temperature sensing (DTS). Air temperature observations obtained from a fiber optics array of approximate dimensions 8 by 8 m and sonic anemometer data from two levels were collected for a period of 23 days over a short grass field located in the flat bottom of a wide valley with moderate surface heterogeneity. In addition to evaluating the DTS technique to resolve the rapidly changing gradients and small-scale perturbations associated with turbulence in the atmosphere for convective and stable boundary layers, the objective was to analyze the space-time dynamics of transient cold-air pools in the stable boundary layer. The time response and precision of the fiber temperatures were adequate to resolve individual sub-meter sized turbulent and non-turbulent structures of time scales >= 3 s and enabled calculation of meaningful sensible heat fluxes when combined with vertical wind observations. The small turbulence scales associated with strong vertical shear and low measurement heights pose limitations to the technique. The top of the transient cold-air pool was highly non-stationary. The thermal structure of the near-surface air is generally a superposition of various perturbations of different time and length scales, whereas no preferred scales were identified. Vertical length scales for turbulence in the strongly stratified transient cold-air pool directly derived from the DTS data agreed well with buoyancy length scales parameterized using the vertical velocity variance and the Brunt-Vaisala frequency, while scales for weak stratification disagreed. The high-resolution DTS technique opens a new window into spatially sampling geophysical fluid flows including turbulent energy exchange with a broad

  10. Influence of pressure, temperature, and pore fluid on the frequency-dependent attenuation of elastic waves in Berea sandstone

    NASA Astrophysics Data System (ADS)

    O'hara, Stephen G.

    1985-07-01

    The effects of pore fluid, effective stress, pore fluid pressure, and temperature on the frequency dependence of elastic wave attenuation in Berea sandstone are interrelated in a series of systematic experiments. The attenuation of both the extensional and torsional modes of cylindrical samples of the sandstone is measured on the frequency range 3-30 kHz. To simulate conditions within the earth, the sandstone is subjected to confining stress to 70.0 MPa and temperature from 24.0 °C to 120.0 °C. Confining pressure and pore fluid pressure are varied independently. Data for two different pore fluids, brine and n-heptane, suggest that a scaling law exists for the pressure and temperature dependence of the attenuation in terms of the pore fluid. The logarithmic decrement of the sandstone is almost frequency independent in a vacuum evacuated sample, but shows a linear frequency dependence, once the sample is saturated. Extrapolation of this linear trend to low frequencies suggests that the decrement in fluid-filled sandstone is effectively frequency independent at seismic frequencies (<100 Hz). The frequency dependence becomes more pronounced as either the effective stress or the temperature is decreased. When the difference between the external stress on the sandstone and the pore fluid pressure is large, the attenuation depends only on the effective stress and is relatively temperature independent. But at low effective stress, the attenuation increases linearly with increasing pore fluid pressure and decreases linearly with increasing temperature. While a specific model is lacking, the attenuation process is apparently influenced most strongly by chemical processes at the pore fluid-matrix interface accompanied by subtle changes in the sandstone matrix dimensions.

  11. Comparative Risks of Aldehyde Constituents in Cigarette Smoke Using Transient Computational Fluid Dynamics/Physiologically Based Pharmacokinetic Models of the Rat and Human Respiratory Tracts.

    PubMed

    Corley, Richard A; Kabilan, Senthil; Kuprat, Andrew P; Carson, James P; Jacob, Richard E; Minard, Kevin R; Teeguarden, Justin G; Timchalk, Charles; Pipavath, Sudhakar; Glenny, Robb; Einstein, Daniel R

    2015-07-01

    Computational fluid dynamics (CFD) modeling is well suited for addressing species-specific anatomy and physiology in calculating respiratory tissue exposures to inhaled materials. In this study, we overcame prior CFD model limitations to demonstrate the importance of realistic, transient breathing patterns for predicting site-specific tissue dose. Specifically, extended airway CFD models of the rat and human were coupled with airway region-specific physiologically based pharmacokinetic (PBPK) tissue models to describe the kinetics of 3 reactive constituents of cigarette smoke: acrolein, acetaldehyde and formaldehyde. Simulations of aldehyde no-observed-adverse-effect levels for nasal toxicity in the rat were conducted until breath-by-breath tissue concentration profiles reached steady state. Human oral breathing simulations were conducted using representative aldehyde yields from cigarette smoke, measured puff ventilation profiles and numbers of cigarettes smoked per day. As with prior steady-state CFD/PBPK simulations, the anterior respiratory nasal epithelial tissues received the greatest initial uptake rates for each aldehyde in the rat. However, integrated time- and tissue depth-dependent area under the curve (AUC) concentrations were typically greater in the anterior dorsal olfactory epithelium using the more realistic transient breathing profiles. For human simulations, oral and laryngeal tissues received the highest local tissue dose with greater penetration to pulmonary tissues than predicted in the rat. Based upon lifetime average daily dose comparisons of tissue hot-spot AUCs (top 2.5% of surface area-normalized AUCs in each region) and numbers of cigarettes smoked/day, the order of concern for human exposures was acrolein > formaldehyde > acetaldehyde even though acetaldehyde yields were 10-fold greater than formaldehyde and acrolein. PMID:25858911

  12. Comparative Risks of Aldehyde Constituents in Cigarette Smoke Using Transient Computational Fluid Dynamics/Physiologically Based Pharmacokinetic Models of the Rat and Human Respiratory Tracts

    PubMed Central

    Corley, Richard A.; Kabilan, Senthil; Kuprat, Andrew P.; Carson, James P.; Jacob, Richard E.; Minard, Kevin R.; Teeguarden, Justin G.; Timchalk, Charles; Pipavath, Sudhakar; Glenny, Robb; Einstein, Daniel R.

    2015-01-01

    Computational fluid dynamics (CFD) modeling is well suited for addressing species-specific anatomy and physiology in calculating respiratory tissue exposures to inhaled materials. In this study, we overcame prior CFD model limitations to demonstrate the importance of realistic, transient breathing patterns for predicting site-specific tissue dose. Specifically, extended airway CFD models of the rat and human were coupled with airway region-specific physiologically based pharmacokinetic (PBPK) tissue models to describe the kinetics of 3 reactive constituents of cigarette smoke: acrolein, acetaldehyde and formaldehyde. Simulations of aldehyde no-observed-adverse-effect levels for nasal toxicity in the rat were conducted until breath-by-breath tissue concentration profiles reached steady state. Human oral breathing simulations were conducted using representative aldehyde yields from cigarette smoke, measured puff ventilation profiles and numbers of cigarettes smoked per day. As with prior steady-state CFD/PBPK simulations, the anterior respiratory nasal epithelial tissues received the greatest initial uptake rates for each aldehyde in the rat. However, integrated time- and tissue depth-dependent area under the curve (AUC) concentrations were typically greater in the anterior dorsal olfactory epithelium using the more realistic transient breathing profiles. For human simulations, oral and laryngeal tissues received the highest local tissue dose with greater penetration to pulmonary tissues than predicted in the rat. Based upon lifetime average daily dose comparisons of tissue hot-spot AUCs (top 2.5% of surface area-normalized AUCs in each region) and numbers of cigarettes smoked/day, the order of concern for human exposures was acrolein > formaldehyde > acetaldehyde even though acetaldehyde yields were 10-fold greater than formaldehyde and acrolein. PMID:25858911

  13. Heteromeric Heat-sensitive Transient Receptor Potential Channels Exhibit Distinct Temperature and Chemical Response*

    PubMed Central

    Cheng, Wei; Yang, Fan; Liu, Shuang; Colton, Craig K.; Wang, Chunbo; Cui, Yuanyuan; Cao, Xu; Zhu, Michael X.; Sun, Changsen; Wang, KeWei; Zheng, Jie

    2012-01-01

    TRPV1 and TRPV3 are two heat-sensitive ion channels activated at distinct temperature ranges perceived by human as hot and warm, respectively. Compounds eliciting human sensations of heat or warmth can also potently activate these channels. In rodents, TRPV3 is expressed predominantly in skin keratinocytes, whereas in humans TRPV1 and TRPV3 are co-expressed in sensory neurons of dorsal root ganglia and trigeminal ganglion and are known to form heteromeric channels with distinct single channel conductances as well as sensitivities to TRPV1 activator capsaicin and inhibitor capsazepine. However, how heteromeric TRPV1/TRPV3 channels respond to heat and other stimuli remains unknown. In this study, we examined the behavior of heteromeric TRPV1/TRPV3 channels activated by heat, capsaicin, and voltage. Our results demonstrate that the heteromeric channels exhibit distinct temperature sensitivity, activation threshold, and heat-induced sensitization. Changes in gating properties apparently originate from interactions between TRPV1 and TRPV3 subunits. Our results suggest that heteromeric TRPV1/TRPV3 channels are unique heat sensors that may contribute to the fine-tuning of sensitivity to sensory inputs. PMID:22184123

  14. Fluid dynamic design and experimental study of an aspirated temperature measurement platform used in climate observation.

    PubMed

    Yang, Jie; Liu, Qingquan; Dai, Wei; Ding, Renhui

    2016-08-01

    Due to the solar radiation effect, current air temperature sensors inside a thermometer screen or radiation shield may produce measurement errors that are 0.8 °C or higher. To improve the observation accuracy, an aspirated temperature measurement platform is designed. A computational fluid dynamics (CFD) method is implemented to analyze and calculate the radiation error of the aspirated temperature measurement platform under various environmental conditions. Then, a radiation error correction equation is obtained by fitting the CFD results using a genetic algorithm (GA) method. In order to verify the performance of the temperature sensor, the aspirated temperature measurement platform, temperature sensors with a naturally ventilated radiation shield, and a thermometer screen are characterized in the same environment to conduct the intercomparison. The average radiation errors of the sensors in the naturally ventilated radiation shield and the thermometer screen are 0.44 °C and 0.25 °C, respectively. In contrast, the radiation error of the aspirated temperature measurement platform is as low as 0.05 °C. This aspirated temperature sensor allows the radiation error to be reduced by approximately 88.6% compared to the naturally ventilated radiation shield, and allows the error to be reduced by a percentage of approximately 80% compared to the thermometer screen. The mean absolute error and root mean square error between the correction equation and experimental results are 0.032 °C and 0.036 °C, respectively, which demonstrates the accuracy of the CFD and GA methods proposed in this research. PMID:27587139

  15. Influence of fluid temperature gradient on the flow within the shaft gap of a PLR pump

    NASA Astrophysics Data System (ADS)

    Qian, W.; Rosic, B.; Zhang, Q.; Khanal, B.

    2016-03-01

    In nuclear power plants the primary-loop recirculation (PLR) pump circulates the high temperature/high-pressure coolant in order to remove the thermal energy generated within the reactor. The pump is sealed using the cold purge flow in the shaft seal gap between the rotating shaft and stationary casing, where different forms of Taylor-Couette flow instabilities develop. Due to the temperature difference between the hot recirculating water and the cold purge water (of order of 200 °C), the flow instabilities in the gap cause temperature fluctuations, which can lead to shaft or casing thermal fatigue cracks. The present work numerically investigated the influence of temperature difference and rotating speed on the structure and dynamics of the Taylor-Couette flow instabilities. The CFD solver used in this study was extensively validated against the experimental data published in the open literature. Influence of temperature difference on the fluid dynamics of Taylor vortices was investigated in this study. With large temperature difference, the structure of the Taylor vortices is greatly stretched at the interface region between the annulus gap and the lower recirculating cavity. Higher temperature difference and rotating speed induce lower fluctuating frequency and smaller circumferential wave number of Taylor vortices. However, the azimuthal wave speed remains unchanged with all the cases tested. The predicted axial location of the maximum temperature fluctuation on the shaft is in a good agreement with the experimental data, identifying the region potentially affected by the thermal fatigue. The physical understandings of such flow instabilities presented in this paper would be useful for future PLR pump design optimization.

  16. Modeling and simulation of the transient response of temperature and relative humidity sensors with and without protective housing.

    PubMed

    Rocha, Keller Sullivan Oliveira; Martins, José Helvecio; Martins, Marcio Arêdes; Tinôco, Ilda de Fátima Ferreira; Saraz, Jairo Alexander Osorio; Lacerda Filho, Adílio Flauzino; Fernandes, Luiz Henrique Martins

    2014-01-01

    Based on the necessity for enclosure protection of temperature and relative humidity sensors installed in a hostile environment, a wind tunnel was used to quantify the time that the sensors take to reach equilibrium in the environmental conditions to which they are exposed. Two treatments were used: (1) sensors with polyvinyl chloride (PVC) enclosure protection, and (2) sensors with no enclosure protection. The primary objective of this study was to develop and validate a 3-D computational fluid dynamics (CFD) model for analyzing the temperature and relative humidity distribution in a wind tunnel using sensors with PVC enclosure protection and sensors with no enclosure protection. A CFD simulation model was developed to describe the temperature distribution and the physics of mass transfer related to the airflow relative humidity. The first results demonstrate the applicability of the simulation. For verification, a sensor device was successfully assembled and tested in an environment that was optimized to ensure fast change conditions. The quantification setup presented in this paper is thus considered to be adequate for testing different materials and morphologies for enclosure protection. The results show that the boundary layer flow regime has a significant impact on the heat flux distribution. The results indicate that the CFD technique is a powerful tool which provides a detailed description of the flow and temperature fields as well as the time that the relative humidity takes to reach equilibrium with the environment in which the sensors are inserted. PMID:24851994

  17. Modeling and Simulation of the Transient Response of Temperature and Relative Humidity Sensors with and without Protective Housing

    PubMed Central

    Rocha, Keller Sullivan Oliveira; Martins, José Helvecio; Martins, Marcio Arêdes; Ferreira Tinôco, Ilda de Fátima; Saraz, Jairo Alexander Osorio; Filho, Adílio Flauzino Lacerda; Fernandes, Luiz Henrique Martins

    2014-01-01

    Based on the necessity for enclosure protection of temperature and relative humidity sensors installed in a hostile environment, a wind tunnel was used to quantify the time that the sensors take to reach equilibrium in the environmental conditions to which they are exposed. Two treatments were used: (1) sensors with polyvinyl chloride (PVC) enclosure protection, and (2) sensors with no enclosure protection. The primary objective of this study was to develop and validate a 3-D computational fluid dynamics (CFD) model for analyzing the temperature and relative humidity distribution in a wind tunnel using sensors with PVC enclosure protection and sensors with no enclosure protection. A CFD simulation model was developed to describe the temperature distribution and the physics of mass transfer related to the airflow relative humidity. The first results demonstrate the applicability of the simulation. For verification, a sensor device was successfully assembled and tested in an environment that was optimized to ensure fast change conditions. The quantification setup presented in this paper is thus considered to be adequate for testing different materials and morphologies for enclosure protection. The results show that the boundary layer flow regime has a significant impact on the heat flux distribution. The results indicate that the CFD technique is a powerful tool which provides a detailed description of the flow and temperature fields as well as the time that the relative humidity takes to reach equilibrium with the environment in which the sensors are inserted. PMID:24851994

  18. Transient receptor potential melastatin-2 and temperature participate in the process of CD38-regulated oxytocin secretion.

    PubMed

    Liu, Hong-Xiang; Ma, Shuang; Nan, Yong; Yang, Wan-Hua

    2016-08-17

    In recent studies, oxytocin showed potential for the treatment of mental diseases. CD38 is essential for oxytocin release, and hence plays a critical role in social behavior. CD38 catalyzes β-NAD into cyclic ADP ribose (cADPR), which could elevate the intracellular Ca by Ca-permeable channels for oxytocin secretion. The temperature-sensitive cation channel, transient receptor potential melastatin-2 (TRPM2), is a cation-nonselective cation and has been shown to affect oxytocin indirectly. The aim of the present study was to verify the participation of temperature and TRPM2 in CD38-regulated oxytocin release. The crude membranes were prepared to isolate the nerve terminals from the posterior pituitary. At 34°C, 37°C, and 39°C, agonists (β-NAD, ADPR, cADPR) and antagonists (8-Br-cADPR, 2-APB) were used to stimulate the nerve terminals. Oxytocin releases were investigated by enzyme-linked immunosorbent assay. In addition, the expression of TRPM2 and CD38 in the hypothalamus and pituitary was detected by western blotting and quantitative PCR. CD38 agonists (β-NAD, cADPR) and antagonist (8-Br-cADPR) could increase or reduce the oxytocin release, respectively. TRPM2 agonist (ADPR) and antagonist (2-APB) alone could also regulate oxytocin release. Furthermore, temperature could increase agonist stimulation and attenuate the antagonist inhibition on oxytocin release. In addition, CD38 and TRPM2 were expressed in the hypothalamus and pituitary at both the mRNA and the protein level. TRPM2 in pituitary nerve terminals plays a role in oxytocin release. Temperature- enhanced oxytocin release by CD38 and TRPM2. TRPM2 might be involved in the process of CD38-regulated oxytocin release. PMID:27348016

  19. Numerical study on the fluid flow pass a square cylinder: The temperature-viscosity dependence

    NASA Astrophysics Data System (ADS)

    Lu, Jianhua; Li, Sheng; Guo, Zhaoli; Shi, Baochang

    2014-10-01

    In this paper, the 2D fluid flow pass a heated/cooled square cylinder exposed to a constant free-stream upward velocity is simulated via a multiple relaxation time (MRT) lattice-Boltzmann (LB) method. The buoyancy effect on the drag and lift coefficients as well as Nusselt number related is compared with the results in the existing literatures to validate the code used. The effect of temperature-viscosity dependence is then investigated to test whether the effect can be neglected or not for the mixed convection case. It is shown that the effect cannot be ignored when |Ri| > 0.15. Fortunately, the effect can be captured by using an effective temperature formula [J. M. Shi, D. Ferlach, M. Breuer, G. Biswas and F. Durst, Phys. Fluids16, 4331 (2004)] in a rather large range of Ri. All the numerical results, from another angle, also demonstrate that the MRT method is an efficient tool in simulating the problems such as the present one.

  20. Evolution of Permeability and Induced Seismicity during Reservoir Stimulation; Role of Fluid Pressure and Thermal Transients on Reactivated Fractured Networks

    NASA Astrophysics Data System (ADS)

    Izadi, G.; Elsworth, D.

    2012-12-01

    We utilize a continuum model of reservoir behavior subject to coupled THMC (thermal, hydraulic, mechanical and chemical) processes to explore the evolution of stimulation-induced seismicity and of permeability in EGS reservoirs. Our continuum model is capable of accommodating changes in effective stresses that result due to the evolving spatial variations in fluid pressure as well as thermal stress and chemical effects. Discrete penny-shaped fractures (~10-1200m) are seeded within the reservoir volume at prescribed (faults) and random (fractures) orientations and with a Gaussian distribution of lengths and location. Failure is calculated from a continuum model using a Coulomb criterion for friction. Energy release magnitude is utilized to obtain the magnitude-moment relation for induced seismicity by location and with time. This model is applied to a single injector (stimulation) to the proposed Newberry EGS field (USA). We stimulate the reservoir in four zones of differing fracture network properties B, C, D and E (shallow to deep) and at four different depths of 2000, 2500, 2750 and 3000 m. The same network of large fractures (density of 0.003 m-1 and spacing 300 m) is applied in all zones and supplemented by more closely spaced fractures with densities of 0.5 m-1 in the shallow zone B, 0.9 m-1 in the intermediate zones C and D and 0.26 m-1 in the deepest zone E. We show that permeability enhancement is modulated by hydraulic, thermal, and chemical (THMC) processes and that permeability increases by an order of magnitude during stimulation at each depth. For the widely spaced fracture networks, the increase in permeability reaches a smaller radius from the injection point and permeability evolution is slower with time compared to the behavior of the closely spaced fracture network. For seismic events that develop with the stimulation, event magnitude (MS) varies in the range -2 to +1.9 and the largest event size (~1.9) corresponds to the largest fractures (~1200m

  1. Energy transfer among CP29 chlorophylls: calculated Förster rates and experimental transient absorption at room temperature.

    PubMed

    Cinque, G; Croce, R; Holzwarth, A; Bassi, R

    2000-10-01

    The energy transfer rates between chlorophylls in the light harvesting complex CP29 of higher plants at room temperature were calculated ab initio according to the Förster mechanism (Förster T. 1948, Ann. Physik. 2:55-67). Recently, the transition moment orientation of CP29 chlorophylls was determined by differential linear dichroism and absorption spectroscopy of wild-type versus mutant proteins in which single chromophores were missing (Simonetto R., Crimi M., Sandonà D., Croce R., Cinque G., Breton J., and Bassi R. 1999. Biochemistry. 38:12974-12983). In this way the Q(y) transition energy and chlorophyll a/b affinity of each binding site was obtained and their characteristics supported by reconstruction of steady-state linear dichroism and absorption spectra at room temperature. In this study, the spectral form of individual chlorophyll a and b ligands within the protein environment was experimentally determined, and their extinction coefficients were also used to evaluate the absolute overlap integral between donors and acceptors employing the Stepanov relation for both the emission spectrum and the Stokes shift. This information was used to calculate the time-dependent excitation redistribution among CP29 chlorophylls on solving numerically the Pauli master equation of the complex: transient absorption measurements in the (sub)picosecond time scale were simulated and compared to pump-and-probe experimental data in the Q(y) region on the native CP29 at room temperature upon selective excitation of chlorophylls b at 640 or 650 nm. The kinetic model indicates a bidirectional excitation transfer over all CP29 chlorophylls a species, which is particularly rapid between the pure sites A1-A2 and A4-A5. Chlorophylls b in mixed sites act mostly as energy donors for chlorophylls a, whereas site B5 shows high and bidirectional coupling independent of the pigment hosted. PMID:11023879

  2. SOLA-PTS: a transient, three-dimensional algorithm for fluid-thermal mixing and wall heat transfer in complex geometries

    SciTech Connect

    Daly, B.J.; Torrey, M.D.

    1984-07-01

    The SOLA-PTS computer code has been developed to analyze fluid-thermal mixing in the cold legs and downcomer of pressurized water reactors in support of the pressurized thermal shock study. SOLA-PTS is a transient, three-dimensional code with the capability of resolving complex geometries using variable cell noding in the three coordinate directions. The computational procedure is second-order accurate and utilizes a state-of-the-art iteration method that allows rapid convergence to an accurate solution for the pressure field. Two different turbulence models are used in the code, a two-equation k-epsilon model that is used in the cold leg pipe away from the HPI inlet and a three-equation k-epsilon-T'/sup 2/ model for use near the HPI inlet and in the downcomer. The physical modeling and the numerical procedure used in SOLA-PTS are described in this report. Applications of the method to two Creare 1/5th-scale experiments are also presented. Two appendices are included which provides a comparison of the two- and three-equation turbulence models, and instructions for setting up and running a problem with SOLA-PTS.

  3. New equations for density, entropy, heat capacity, and potential temperature of a saline thermal fluid

    NASA Astrophysics Data System (ADS)

    Sun, Hongbing; Feistel, Rainer; Koch, Manfred; Markoe, Andrew

    2008-10-01

    A set of fitted polynomial equations for calculating the physical variables density, entropy, heat capacity and potential temperature of a thermal saline fluid for a temperature range of 0-374 °C, pressure range of 0.1-100 MPa and absolute salinity range of 0-40 g/kg is established. The freshwater components of the equations are extracted from the recently released tabulated data of freshwater properties of Wagner and Pruß [2002. The IAPWS formulation 1995 for the thermodynamic properties of ordinary water substance for general and scientific use. Journal of Physical and Chemical Reference Data 31, 387-535]. The salt water component of the equation is based on the near-linear relationship between density, salinity and specific heat capacity and is extracted from the data sets of Feistel [2003. A new extended Gibbs thermodynamic potential of seawater. Progress in Oceanography 58, 43-114], Bromley et al. [1970. Heat capacities and enthalpies of sea salt solutions to 200 °C. Journal of Chemical and Engineering Data 15, 246-253] and Grunberg [1970. Properties of sea water concentrates. In: Third International Symposium on Fresh Water from the Sea, vol. 1, pp. 31-39] in a temperature range 0-200 °C, practical salinity range 0-40, and varying pressure and is also calibrated by the data set of Millero et al. [1981. Summary of data treatment for the international high pressure equation of state for seawater. UNESCO Technical Papers in Marine Science 38, 99-192]. The freshwater and salt water components are combined to establish a workable multi-polynomial equation, whose coefficients were computed through standard linear regression analysis. The results obtained in this way for density, entropy and potential temperature are comparable with those of existing models, except that our new equations cover a wider temperature—(0-374 °C) than the traditional (0-40 °C) temperature range. One can apply these newly established equations to the calculation of in-situ or

  4. An experimental study on the effects of temperature and magnetic field strength on the magnetorheological fluid stability and MR effect.

    PubMed

    Rabbani, Yahya; Ashtiani, Mahshid; Hashemabadi, Seyed Hassan

    2015-06-14

    In this study, the stability and rheological properties of a suspension of carbonyl iron microparticles (CIMs) in silicone oil were investigated within a temperature range of 10 to 85 °C. The effect of adding two hydrophobic (stearic and palmitic) acids on the stability and magnetorheological effect of a suspension of CIMs in silicone oil was studied. According to the results, for preparing a stable and efficient magnetorheological (MR) fluid, additives should be utilized. Therefore, 3 wt% of stearic acid was added to the MR fluid which led to an enhancement of the fluid stability over 92% at 25 °C. By investigating shear stress variation due to the changes in the shear rate for acid-based MR fluids, the maximum yield stress was obtained by fitting the Bingham plastic rheological model at high shear rates. Based on the existing correlations of yield stress and either temperature or magnetic field strength, a new model was fitted to the experimental data to monitor the simultaneous effect of magnetic field strength and temperature on the maximum yield stress. The results demonstrated that as the magnetic field intensified or the temperature decreased, the maximum yield stress increased dramatically. In addition, when the MR fluid reached its magnetic saturation, the viscosity of fluid depended only on the shear rate. PMID:25940850

  5. Effect of porosity and the inlet heat transfer fluid temperature variation on the performance of cool thermal energy storage system

    NASA Astrophysics Data System (ADS)

    Cheralathan, M.; Velraj, R.; Renganarayanan, S.

    2007-06-01

    This paper discusses the results of numerical and experimental study of an encapsulated cool thermal energy storage system. The storage system is a cylindrical storage tank filled with phase change material encapsulated in spherical container, placed in a refrigeration loop. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid and the phase change material at any axial location during the charging period. The present analysis aims at studying the influence of the inlet heat transfer fluid temperature and porosity on system performance. An experimental setup was designed and constructed to conduct the experiments. The results of the model were validated by comparison with experimental results of temperature profiles for different inlet heat transfer fluid temperatures and porosity. The results are in good agreement with the experimental results. The results reported are much useful for designing cool thermal energy storage systems.

  6. Computational fluid dynamics simulations of jet fuel flow near the freeze point temperature

    NASA Astrophysics Data System (ADS)

    Assudani, Rajee

    2006-12-01

    Under low-temperature environmental conditions, the cooling of aircraft fuel results in reduced fluidity with the potential for freezing. Therefore, it is important to study the flow and heat transfer phenomena that occur in an aircraft fuel tank near the freeze point temperature of jet fuels. The purpose of this dissertation is to study the effects of low temperatures on the flow, heat transfer and freezing of commercial and military jet fuels. The research is accomplished with the help of computational models of a thermal simulator tank and a quartz duct. Experimental results with the thermal simulator tank show that fuel flowability and pumpability decrease substantially as temperature is reduced. Time-dependent temperature and velocity distributions were numerically simulated for static cooling. Measured properties were used in all the computational fluid dynamics simulations. The calculations show that stringers, ribs, and other structures strongly promote fuel cooling. Also, the cooler, denser fuel resides near the bottom surface of the fuel tank simulator. The presence of an ullage space within the tank was found to strongly influence the fuel temperature profile by sometimes reducing cooling from the upper surface. Moreover, since the presence of ullage space is an explosion risk, some military aircraft fuel tanks are fitted with explosion suppressant polyurethane foam. To study the effect of foam on the flowability and heat transfer inside the simulator tank, the wing tank thermal simulator was filled with military specified polyurethane foam. The tank was simultaneously drained and cooled and the mass flow rate results showed that flowability of the fuel is not affected by the presence of foam. However, the presence of foam certainly affected the heat transfer phenomenon inside the fuel tank when the simulator tank was cooled and drained simultaneously. To study the freezing behavior of jet fuel under forced flow conditions, a quartz duct was fabricated

  7. Wide-range average temperature measurements of convective fluid flows by using a schlieren system.

    PubMed

    Martínez-González, A; Moreno-Hernández, D; León-Rodríguez, M; Carrillo-Delgado, C

    2016-01-20

    In the schlieren method, the deflection of light by the presence of an inhomogeneous medium is proportional to the gradient of its refractive index. In the presence of temperature variations in a fluid flow, the refraction index is related to the gas density by the Gladstone-Dale constant, which depends on the nature of the gas and the wavelength of light propagating in the medium. The deflection of light in a schlieren system is represented by intensity variations on the observation plane. Then, for a digital camera, the intensity level registered in each pixel depends mainly on the refractive index variation of the medium and exposure time. Therefore, if we regulate the intensity value of each pixel by controlling the exposure time, it is possible to adjust the temperature value measurements. In this way, a specific exposure time of a digital camera allows us to measure a determined range of temperature values. For that reason, in this study we determine the range of temperatures that can be measured with a digital camera for different exposure times. By doing this, a wide range of average temperature value fields can be obtained by summing up the temperature contribution of each exposure time. The basic idea in our approach to measure temperature by using a schlieren system is to relate the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the system. Our approach is applied to the measurement of temperature fields of the air convection caused by a heated rectangular metal plate (7.3  cm×12  cm) and a candle flame. We found that the maximum temperature values obtained for exposure times of 31.3, 15.7, 7.9, 3.9, and 2 ms were 67.3°C, 122.6°C, 217.4°C, 364.3°C, and 524.0°C, respectively. PMID:26835931

  8. Effects of glacial ice on subsurface temperatures of hydrothermal systems in Yellowstone National Park, Wyoming: Fluid-inclusion evidence

    SciTech Connect

    Bargar, K.E.; Fournier, R.O. )

    1988-12-01

    Hydrothermal quartz and fluorite crystals containing liquid-rich fluid inclusions (coexisting vapor-rich fluid inclusions were not observed) were found in drill cores from eight relatively shallow research holes drilled by the US Geological Survey in and near major geyser basins of Yellowstone National Park. Homogenization temperatures (T{sub h}) for mostly secondary fluid inclusions show variations in temperature that have occurred at give depths since precipitation of the host minerals. Within major hydrothermal upflow zones, fluid-inclusion T{sub h} values all were found to be equal to or higher (commonly 20-50 C and up to 155 C higher) than present temperatures at the depths sampled. During periods when thick glacial ice covered the Yellowstone National Park region, pore-fluid pressures in the underlying rock were increased in proportion to the weight of the overlying column of ice. Accordingly, theoretical reference boiling-point curves that reflect the maximum temperature attainable in a hot-water geothermal system at a given depth were elevated, and temperatures within zones of major hydrothermal upflow (drill holes Y-2, Y-3, Y-6, Y-11, Y-13, and upper part of Y-5) increased. The thicknesses of ice required to elevate boiling-point curves sufficiently to account for the observed fluid-inclusion T{sub h} values are within the ranges estimated by glacial geologic studies. At the margins of major hydrothermal upflow zones (drill holes Y-4 and Y-9), fluid-inclusion T{sub h} values at given depths range from 57 C lower to about the same as the current temperature measurements because of a previous decrease in the rate of discharge of warm water and/or an increase in the rate of recharge of cold water into the hydrothermal system.

  9. Comparison of two fluid warming devices for maintaining body core temperature during living donor liver transplantation: Level 1 H-1000 vs. Fluid Management System 2000

    PubMed Central

    Han, Sangbin; Choi, Junghee; Ko, Justin Sangwook; Gwak, Misook; Lee, Suk-Koo

    2014-01-01

    Background Rapid fluid warming has been a cardinal measure to maintain normothermia during fluid resuscitation of hypovolemic patients. A previous laboratory simulation study with different fluid infusion rates showed that a fluid warmer using magnetic induction is superior to a warmer using countercurrent heat exchange. We tested whether the simulation-based result is translated into the clinical liver transplantation. Methods Two hundred twenty recipients who underwent living donor liver transplantation between April 2009 and October 2011 were initially screened. Seventeen recipients given a magnetic induction warmer (FMS2000) were matched 1 : 1 with those given a countercurrent heat exchange warmer (Level-1 H-1000) based on propensity score. Matched variables included age, gender, body mass index, model for end-stage liver disease score, graft size and time under anesthesia. Core temperatures were taken at predetermined time points. Results Level-1 and FMS groups had comparable core temperature throughout the surgery from skin incision, the beginning/end of the anhepatic phase to skin closure. (P = 0.165, repeated measures ANOVA). The degree of core temperature changes within the dissection, anhepatic and postreperfusion phase were also comparable between the two groups. The minimum intraoperative core temperature was also comparable (Level 1, 35.6℃ vs. FMS, 35.4℃, P = 0.122). Conclusions A countercurrent heat exchange warmer and magnetic induction warmer displayed comparable function regarding the maintenance of core temperature and prevention of hypothermia during living donor liver transplantation. The applicability of the two devices in liver transplantation needs to be evaluated in various populations and clinical settings. PMID:25368785

  10. The development of new, low-cost perfluoroalkylether fluids with excellent low and high-temperature properties

    NASA Technical Reports Server (NTRS)

    Bierschenk, Thomas R.; Kawa, Hajimu; Juhlke, Timothy J.; Lagow, Richard J.

    1988-01-01

    A series of perfluoroalkylether (PFAE) fluids were synthesized by direct fluorination. Viscosity-temperature properties, oxidation stabilities, oxidation-corrosion properties, and lubricity were determined. The fluids were tested in the presence of common elastomers to check for compatibility. The bulk modulus of each was measured to determine if any could be used as nonflammable aircraft hydraulic fluid. It was determined that as the carbon to oxygen ratio decreases, the viscometric properties improve, the fluids may become poor lubricants, the bulk modulus increases, the surface tension increases, and the fluid density increases. The presence of difluoromethylene oxide units in the polymer does not seriously lower the oxidation and oxidation-corrosion stabilities as long as the difluoromethylene oxide units are separated by other units.

  11. Embedded MicroHeating Elements in Polymeric MicroChannels for Temperature Control and Fluid Flow Sensing

    PubMed Central

    Gaitan, Michael; Locascio, Laurie E.

    2004-01-01

    This paper describes the first demonstration of temperature control and flow sensing of fluids using integrated circuit (IC)-based microheating elements embedded in microchannels molded in polydimethylsiloxane (PDMS). Fluid channels and connections to capillary tubing are molded in PDMS using a silicon wafer template. The PDMS film is then bonded to an IC that contains the micromachined microheating elements. Capillary tubes are inserted and fluids are externally pumped through the channels. Heating of the fluid is observed by the formation of bubbles on the microheating element. Sensing of fluid flow is demonstrated by measuring a change in the large signal resistance of the microheater analogous to a hot wire anemometer with a detection limit of ± 320 pL/s. PMID:27366617

  12. On the application of a physically based higher order fluid model for low-temperature plasmas

    NASA Astrophysics Data System (ADS)

    Garland, Nathan; White, Ron; Robson, Robert; Nicoletopoulos, Peter; Dujko, Sasa

    2012-10-01

    We present a high resolution, computationally efficient non-local fluid model of a low-temperature parallel plate plasma discharge. The non-local model uses low-order velocity moments of the Boltzmann equation representing particle, momentum and energy balance equations, coupled with Poisson's equations to determine space-charge fields. The system of equations is closed used a physically sound heat flux ansatz [1]. A new scheme is implemented for prescribing the relevant collisional terms in the balance equations, based on available electron swarm transport coefficients [2]. The model is applied to simulation of various configurations including the Gaseous Electronics Conference (GEC) reference cell and compared to previous models of the system. Results of the model yield spatial and temporal profiles of electron densities, flux and energy in addition to electric field distributions inside the GEC reference cell. In this paper, we highlight differences associated with local and non-local fluid equation treatments, as well as highlight the importance of correct implementation of electron swarm transport data. [1] R.E. Robson, R.D. White and Z. Lj. Petrovic, Rev. Mod. Phys. 77, 1303 (2005) [2] R.E. Robson, P. Nicoletopoulos, M. Hildebrandt and R.D. White, J. Chem. Phys. (sub

  13. Fluid Phase Lipid Areas and Bilayer Thicknesses of Commonly Used Phosphatidylcholines as a Function of Temperature

    SciTech Connect

    Kucerka, Norbert; Nieh, Mu-Ping; Katsaras, John

    2011-01-01

    The structural parameters of fluid phase bilayers composed of phosphatidylcholines with fully saturated, mixed, and branched fatty acid chains, at several temperatures, have been determined by simultaneously analyzing small-angle neutron and X-ray scattering data. Bilayer parameters, such as area per lipid and overall bilayer thickness have been obtained in conjunction with intrabilayer structural parameters (e.g. hydrocarbon region thickness). The results have allowed us to assess the effect of temperature and hydrocarbon chain composition on bilayer structure. For example, we found that for all lipids there is, not surprisingly, an increase in fatty acid chain trans-gauche isomerization with increasing temperature. Moreover, this increase in trans-gauche isomerization scales with fatty acid chain length in mixed chain lipids. However, in the case of lipids with saturated fatty acid chains, trans-gauche isomerization is increasingly tempered by attractive chain-chain van der Waals interactions with increasing chain length. Finally, our results confirm a strong dependence of lipid chain dynamics as a function of double bond position along fatty acid chains.

  14. Plate-like convection in fluids with temperature-dependent viscosity

    NASA Astrophysics Data System (ADS)

    Mancho, Ana M.; Curbelo, Jezabel

    2013-11-01

    The study of instabilities in fluids in which viscosity experiences a transition at a certain temperature range is of great interest for the understanding of planetary interiors, since this phenomena models the melting and solidification of a magma ocean and thus is suitable for representing a lithosphere over a convecting mantle. To this end, we study a 2D convection problem in which viscosity depends on temperature by abruptly changing its value by a factor 400 within a narrow temperature gap at which magma melts. We perform a study which combines bifurcation analysis and time dependent simulations. Solutions such as limit cycles are found that are fundamentally related to the presence of the O(2) symmetry. Sporadically during these cycles, through abrupt bursts, spontaneous plate-like behaviors that rapidly evolve towards a stagnant lid regime emerge. The plate-like evolution alternates motions towards either right or left, introducing temporary asymmetries on the convecting styles. Further time dependent regimes are described for different transition laws which are greatly influenced by the presence of the symmetry. We thank CESGA for computing facilities. This research is supported by the Spanish Ministry of Science under grant MTM2011-26696 and MINECO: ICMAT Severo Ochoa project SEV-2011-0087.

  15. Effect of gravitational acceleration on temperature wave propagation in a critical fluid

    SciTech Connect

    Ishii, K.; Maekawa, T.; Azuma, H.; Yoshihara, S.; Onishi, M.

    1998-01-01

    Temperature propagation near the critical point of a classical fluid is investigated theoretically. The governing equations of thermal energy transfer near the critical point are introduced and a linear analysis is carried out. The dispersion relation between the angular frequency and the wave number is obtained and the wave characteristics are discussed. The effect of gravitational acceleration on the temperature wave propagation is made clear. Through this analysis, the following results were obtained; (1) The propagation speed of temperature waves is {radical} ({gamma}/({rho}{sub 0}{kappa}{sub T})) ,where {gamma}, {rho}{sub 0}, and {kappa}{sub T} are, respectively, the ratio of specific heats, the density, and the isothermal compressibility, with or without gravity if the wavelength is larger than 10{sup {minus}3}.(2) The amplitude of wave increases with time in the antigravitational direction and decreases in the gravitational direction but the decay time is long if the wave number is small. (3) Waves decay quickly if the wave number is larger than 10{sup 4}. {copyright} {ital 1998 American Institute of Physics.}

  16. Electrical conductivity of lawsonite and dehydrating fluids at high pressures and temperatures

    NASA Astrophysics Data System (ADS)

    Manthilake, Geeth; Mookherjee, Mainak; Bolfan-Casanova, Nathalie; Andrault, Denis

    2015-09-01

    Lawsonite is a calcium-aluminum bearing hydrous silicate mineral with CaAl2Si2O7(OH)2.H2O stoichiometry. It is thermodynamically stable in the hydrated oceanic crust. Low-velocity anomalies observed in the cold subducted slabs have been related to the unusual shear wave velocities of lawsonite eclogite. However, electrical conductivity of lawsonite at high pressure and temperature remains unknown. In this study, we measured the electrical conductivity of lawsonite at 7 GPa, and temperatures ranging from 298 K-1320 K. At 1173 K, the electrical conductivity of lawsonite is around 10-1 S/m. A sharp increase of electrical conductivity is observed at temperatures exceeding the dehydration ~1258 K. The high electrical conductivity up to 101 S/m observed in our experiments is due to the presence of highly conductive fluid and could explain the low resistivity observed at 150-250 km depths in subduction zone settings such as NE Japan, northern, and central Chile.

  17. Transmission line pulse properties for a bidirectional transient voltage suppression diode fabricated using low-temperature epitaxy

    NASA Astrophysics Data System (ADS)

    Bouangeune, Daoheung; Cho, Deok-Ho; Yun, Hyung-Joong; Shim, Kyu-Hwan; Choi, Chel-Jong

    2015-01-01

    Based on low temperature epitaxy technology, a bidirectional transient voltage suppression (TVS) diode with abrupt multi-junctions was developed. The bidirectional triggering voltage of ±16 V was controlled by the thickness and dopant concentration in the multi-junctions using a reduced-pressure chemical vapor deposition (RPCVD) process. The manufactured TVS diode showed a small leakage current density and dynamic resistance of less than 5.1 × 10-14 A/ µm2 and 1 O, respectively, which could be associated with the epitaxially grown abrupt multijunctions. The transmission line pulse (TLP) analysis results demonstrated that the bidirectional TVS diodes were capable of withstanding a peak pulse current of up to ±20 A or ±1.02 × 10-3 A/ µm2, which is equivalent to ±40 kV of the human body model (HBM) and ±12 kV of IEC61000-4-2 (IEC). Nevertheless, the electrostatic discharge (ESD) design window showed that bidirectional TVS diodes meet IEC level 4 standard ESD protection requirements (8 kV in contact discharge). In addition, because of the bidirectional structure, the TVS devices exhibited a small capacitance of 4.9 pF, which confirms that the TVS diode can be used for protecting high data rate communication lines (over 500 Mbps) from ESD shock.

  18. How stress and temperature conditions affect rock-fluid chemistry and mechanical deformation

    NASA Astrophysics Data System (ADS)

    Nermoen, Anders; Korsnes, Reidar; Aursjø, Olav; Madland, Merete; Kjørslevik, Trygve Alexander; Østensen, Geir

    2016-02-01

    We report the results from a series of chalk flow-through-compaction experiments performed at three effective stresses (0.5 MPa, 3.5 MPa and 12.3 MPa) and two temperatures (92° and and 130°). The results show that both stress and temperature are important to both chemical alteration and mechanical deformation. The experiments were conducted on cores drilled from the same block of outcrop chalks from the Obourg quarry within the Saint Vast formation (Mons, Belgium). The pore pressure was kept at 0.7 MPa for all experiments with a continuous flow of 0.219 M MgCl2 brine at a constant flow rate; 1 original pore volume (PV) per day. The experiments have been performed in tri-axial cells with independent control of the external stress (hydraulic pressure in the confining oil), pore pressure, temperature, and the injected flow rate. Each experiment consists of two phases; a loading phase where stress-strain dependencies are investigated (approx. 2 days), and a creep phase that lasts for more than 150-160 days. During creep, the axial deformation was logged, and the effluent samples were collected for ion chromatography analyses. Any difference between the injected and produced water chemistry gives insight into the rock-fluid interactions that occur during flow through of the core. The observed effluent concentration shows a reduction in Mg2+, while the Ca2+ concentration is increased. This, together with SEM-EDS analysis, indicates that magnesium-bearing mineral phases are precipitated leading to dissolution of calcite, an observation . This is in-line with other flow-through experiments reported earlier. The observed dissolution and precipitation are sensitive to the effective stress and test temperature. Typically. H, higher stress and temperature lead to increased concentration differences of Mg2+ and Ca2+ concentration changes.. The observed strain can be partitioned additively into a mechanical and chemical driven component.

  19. Pressure-temperature-fluid constraints for the Emmaville-Torrington emerald deposit, New South Wales, Australia: Fluid inclusion and stable isotope studies

    NASA Astrophysics Data System (ADS)

    Loughrey, Lara; Marshall, Dan; Jones, Peter; Millsteed, Paul; Main, Arthur

    2012-06-01

    The Emmaville-Torrington emeralds were first discovered in 1890 in quartz veins hosted within a Permian metasedimentary sequence, consisting of meta-siltstones, slates and quartzites intruded by pegmatite and aplite veins from the Moule Granite. The emerald deposit genesis is consistent with a typical granite-related emerald vein system. Emeralds from these veins display colour zonation alternating between emerald and clear beryl. Two fluid inclusion types are identified: three-phase (brine+vapour+halite) and two-phase (vapour+liquid) fluid inclusions. Fluid inclusion studies indicate the emeralds were precipitated from saline fluids ranging from approximately 33 mass percent NaCl equivalent. Formational pressures and temperatures of 350 to 400 °C and approximately 150 to 250 bars were derived from fluid inclusion and petrographic studies that also indicate emerald and beryl precipitation respectively from the liquid and vapour portions of a two-phase (boiling) system. The distinct colour zonations observed in the emerald from these deposits is the first recorded emerald locality which shows evidence of colour variation as a function of boiling. The primary three-phase and primary two-phase FITs are consistent with alternating chromium-rich `striped' colour banding. Alternating emerald zones with colourless beryl are due to chromium and vanadium partitioning in the liquid portion of the boiling system. The chemical variations observed at Emmaville-Torrington are similar to other colour zoned emeralds from other localities worldwide likely precipitated from a boiling system as well.

  20. Variation in Lithium Isotopes During Fluid-Shale Interactions at Elevated Pressure and Temperature

    NASA Astrophysics Data System (ADS)

    Phan, T. T.; Paukert, A. N.; Hakala, A.

    2015-12-01

    Naturally-occurring isotopes are useful tracers of fluid mixing in complex natural systems, and have been applied towards evaluating the sources of elevated total dissolved solids in water produced from unconventional oil and gas operations. Prior investigations showed that elevated Li in saline waters co-produced with natural gas during Marcellus Shale development resulted from mixing of hydraulic fracturing fluid (HFF) and Li-rich formation water. However, specific contributions to the Li isotope signature from reactions between the HFF and shale remained unclear. This study focused on HFF-shale reactions that could affect the Li budget and isotope composition in Marcellus Shale produced water in a series of flow through experiments conducted at fixed temperature and pressure (66oC, 20MPa) comparable to formation conditions. Synthetic HFF was prepared by mixing either freshwater or a lab-derived saline water with chemical additives commonly used in hydraulic fracturing. Outcrop cores of Marcellus Shale were artificially fractured either parallel to or perpendicular to bedding prior to loading into the flow-through apparatus, and each experiment was performed with a unique HFF composition continuously pumped through a fresh core (15 cm in length, 3.8 cm in diameter). Initial fluid and cumulative effluents collected after 2 days and 7 days from the start of the experiment were measured for concentrations of cations and anions. Multi-collector ICP-MS was used to measure lithium isotope ratios (δ7Li). Preliminary results show that dissolution of carbonate minerals occurred in both replicate experiments with freshwater-based HFF (pH 2) as shown by a large decrease in Li/Ca from 0.8 (initial fluid) to 0.003 (effluents on day 2 and day 7) with no significant change in Li concentration. This is consistent with low Li in carbonate cement (<2%) and water soluble (<8%) and exchangeable (<2%) fractions of Marcellus Shale. Variation in δ7Li values is within analytical

  1. Design and feasibility of high temperature nanoparticle fluid filter in hybrid thermal/photovoltaic concentrating solar power

    NASA Astrophysics Data System (ADS)

    DeJarnette, Drew; Brekke, Nick; Tunkara, Ebrima; Hari, Parameswar; Roberts, Kenneth; Otanicar, Todd

    2015-09-01

    A nanoparticle fluid filter used with concentrating hybrid solar/thermal collector design is presented. Nanoparticle fluid filters could be situated on any given concentrating system with appropriate customized engineering. This work shows the design in the context of a trough concentration system. Geometric design and physical placement in the optical path was modeled using SolTrace. It was found that a design can be made that blocks 0% of the traced rays. The nanoparticle fluid filter is tunable for different concentrating systems using various PV cells or operating at varying temperatures.

  2. Three-dimensional natural convection of a fluid with temperature-dependent viscosity in an enclosure with localized heating

    SciTech Connect

    Torczynski, J.R.; Henderson, J.A.; O`Hern, T.J.; Chu, T.Y.; Blanchat, T.K.

    1994-01-01

    Three-dimensional natural convection of a fluid in an enclosure is examined. The geometry is motivated by a possible magmaenergy extraction system, and the fluid is a magma simulant and has a highly temperature-dependent viscosity. Flow simulations are performed for enclosures with and without a cylinder, which represents the extractor, using the finite-element code FIDAP (Fluid Dynamics International). The presence of the cylinder completely alters the flow pattern. Flow-visualization and PIV experiments are in qualitative agreement wit the simulations.

  3. Hydromagnetic Steady Flow of Maxwell Fluid over a Bidirectional Stretching Surface with Prescribed Surface Temperature and Prescribed Surface Heat Flux

    PubMed Central

    Shehzad, Sabir Ali; Alsaedi, Ahmad; Hayat, Tasawar

    2013-01-01

    This paper investigates the steady hydromagnetic three-dimensional boundary layer flow of Maxwell fluid over a bidirectional stretching surface. Both cases of prescribed surface temperature (PST) and prescribed surface heat flux (PHF) are considered. Computations are made for the velocities and temperatures. Results are plotted and analyzed for PST and PHF cases. Convergence analysis is presented for the velocities and temperatures. Comparison of PST and PHF cases is given and examined. PMID:23874523

  4. Predicting critical temperatures of ionic and non-ionic fluids from thermophysical data obtained near the melting point.

    PubMed

    Weiss, Volker C

    2015-10-14

    In the correlation and prediction of thermophysical data of fluids based on a corresponding-states approach, the critical temperature Tc plays a central role. For some fluids, in particular ionic ones, however, the critical region is difficult or even impossible to access experimentally. For molten salts, Tc is on the order of 3000 K, which makes accurate measurements a challenging task. Room temperature ionic liquids (RTILs) decompose thermally between 400 K and 600 K due to their organic constituents; this range of temperatures is hundreds of degrees below recent estimates of their Tc. In both cases, reliable methods to deduce Tc based on extrapolations of experimental data recorded at much lower temperatures near the triple or melting points are needed and useful because the critical point influences the fluid's behavior in the entire liquid region. Here, we propose to employ the scaling approach leading to universal fluid behavior [Román et al., J. Chem. Phys. 123, 124512 (2005)] to derive a very simple expression that allows one to estimate Tc from the density of the liquid, the surface tension, or the enthalpy of vaporization measured in a very narrow range of low temperatures. We demonstrate the validity of the approach for simple and polar neutral fluids, for which Tc is known, and then use the methodology to obtain estimates of Tc for ionic fluids. When comparing these estimates to those reported in the literature, good agreement is found for RTILs, whereas the ones for the molten salts NaCl and KCl are lower than previous estimates by 10%. The coexistence curve for ionic fluids is found to be more adequately described by an effective exponent of βeff = 0.5 than by βeff = 0.33. PMID:26472385

  5. Quartz-bearing C O H fluid inclusions diamond: Retracing the pressure temperature path in the mantle using calibrated high temperature IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Tomlinson, Emma L.; McMillan, Paul F.; Zhang, Ming; Jones, Adrian P.; Redfern, Simon A. T.

    2007-12-01

    Infrared spectra of C-O-H micro-inclusions were collected from a micro-inclusion bearing diamond during step-heating and freezing experiments to examine fluid speciation as a function of pressure and temperature. The inclusions contain H 2O, CO 2, carbonate, apatite, quartz and mica, which together represent the oxidising remnant mantle fluid composition after diamond crystallisation. The internal pressure of the inclusions, measured from calibrated shifts of the quartz peaks, increases from 1.3 GPa at ambient temperature, to approximately 4-5 GPa at 737 °C, close to the conditions of crystallisation of the host diamond in the mantle.

  6. Temperature effects in supercritical fluid chromatography: a trade-off between viscous heating and decompression cooling.

    PubMed

    De Pauw, Ruben; Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

    2014-10-24

    The study of radial and axial temperature profiles always has been an area interest both in liquid chromatography (LC) and supercritical fluid chromatography (SFC). Whereas in LC always an increase in temperature is observed due to the dominance of viscous heating, in SFC, especially for low modifier content, a decrease in temperature is found due to the much larger decompression cooling. However, for higher modifier content and higher operating pressure, the temperature effects become a trade-off between viscous heating and decompression cooling, since in SFC the latter is a strong function of operating pressure and mobile phase composition. At a temperature of 40°C and for neat CO2, the effect of decompression cooling and viscous heating cancel each other out at a pressure 450bar. This pressure decreases almost linearly with volume fraction of methanol to 150bar at 25vol%. As a result, both cooling and heating effects can be observed when operating at high back pressure, large column pressure drops or high modifier content. For example at a back pressure of 150bar and a column pressure drop of 270bar decompression cooling is observed throughout the column. However at 300bar back pressure and the same pressure drop, the mobile phase heats up in the first part of the column due to viscous heating and then cools in the second part due to decompression cooling. When coupling columns (2.1mm×150mm, 1.8μm fully porous particles) at very high operating pressure (e.g. 750bar for 8vol%), the situation is even more complex. E.g. at a back pressure of 150bar and using 8vol% methanol, viscous heating is only observed in the first column whereas only decompression cooling in the second. Further increasing the inlet pressure up to 1050bar resulted in no excessive temperature differences along the column. This implies that the inlet pressure of SFC instrumentation could be expanded above 600bar without additional band broadening caused by excessive radial temperature

  7. Comparison of Theoretically and Experimentally Determined Effects of Oxide Coatings Supplied by Fuel Additives on Uncooled Turbine-blade Temperature During Transient Turbojet-engine Operation

    NASA Technical Reports Server (NTRS)

    Schafer, Louis J; Stepka, Francis S; Brown, W Byron

    1953-01-01

    An analysis was made to permit the calculation of the effectiveness of oxide coatings in retarding the transient heat flow into turbine blades when the combustion gas temperature of a turbojet engine is suddenly changed. The analysis is checked with experimental data obtained from a turbojet engine whose blades were coated with two different coating materials (silicon dioxide and boric oxide) by adding silicone oil and tributyl borate to the engine fuel. The very thin coatings (approximately 0.001 in.) that formed on the blades produced a negligible effect on the turbine-blade transient temperature response. With the analysis discussed here, it was possible to predict the turbine rotor-blade temperature response with a maximum error of 40 F.

  8. Characterization and Optimization of Temperature-Sensitive Microbeads for Simultaneous Thermometry and Velocimetry for Fluid Dynamic Applications

    NASA Astrophysics Data System (ADS)

    Cottingham, Trey

    Luminescent paint is an established method for measuring both pressure and temperature distributions on surfaces. These Temperature-Sensitive Paints (TSP) and Pressure-Sensitive Paints (PSP) are commercially available and used regularly in the study of fluids. New microbeads using temperature-sensitive dyes were developed for applications in wind and water tunnel measurement. A novel method was developed to measure their response times to temperature changes. Their sensitivity to temperature change was also measured. A new optical system and software suite were developed. Methods for reducing spatial variations due to excitation energy were also developed.

  9. Simulation of temperature profiles at the superfluid to normal-fluid interface in helium-4 for prediction of temperature measurement accuracy

    SciTech Connect

    Hensinger, D.M.; Gianoulakis, S.E.; Duncan, R.V.

    1996-12-31

    The purpose of this work was to model the conditions in a test cell containing normal-fluid and superfluid helium-4 and to predict the accuracy of temperature measurements made on this system in the presence of non-ideal wall materials and probe geometries. A thermal model of helium-4 in the vicinity of its normal-fluid to superfluid transition temperature was used to calculate the temperature profiles within a helium-4 filled experimental test cell. Calculated temperature profiles were used to predict the temperature measurement accuracy which could be expected from a test cell and temperature probe design. The superfluid phase of helium-4 was represented as a highly-conductive, diffusive material to approximate a superconductor of heat. The thermal model included the influences of temperature, heat flux, and hydrostatic pressure on the properties of helium-4. The model was solved for quasi-static temperature profiles using a finite element method and employing a transformed and expanded temperature scale to allow resolution of nK/cm temperature gradients in the presence of a 2 K absolute temperature.

  10. MHD thermosolutal marangoni convection heat and mass transport of power law fluid driven by temperature and concentration gradient

    NASA Astrophysics Data System (ADS)

    Jiao, Chengru; Zheng, Liancun; Ma, Lianxi

    2015-08-01

    This paper studies the magnetohydrodynamic (MHD) thermosolutal Marangoni convection heat and mass transfer of power-law fluids driven by a power law temperature and a power law concentration which is assumed that the surface tension varies linearly with both the temperature and concentration. Heat and mass transfer constitutive equation is proposed based on N-diffusion proposed by Philip and the abnormal convection-diffusion model proposed by Pascal in which we assume that the heat diffusion depends non-linearly on both the temperature and the temperature gradient and the mass diffusion depends non-linearly on both the concentration and the concentration gradient with modified Fourier heat conduction for power law fluid. The governing equations are reduced to nonlinear ordinary differential equations by using suitable similarity transformations. Approximate analytical solution is obtained using homotopy analytical method (HAM). The transport characteristics of velocity, temperature and concentration fields are analyzed in detail.

  11. Effect of drilling fluid systems and temperature on oil mist and vapour levels generated from shale shaker.

    PubMed

    Steinsvåg, Kjersti; Galea, Karen S; Krüger, Kirsti; Peikli, Vegard; Sánchez-Jiménez, Araceli; Sætvedt, Esther; Searl, Alison; Cherrie, John W; van Tongeren, Martie

    2011-05-01

    Workers in the drilling section of the offshore petroleum industry are exposed to air pollutants generated by drilling fluids. Oil mist and oil vapour concentrations have been measured in the drilling fluid processing areas for decades; however, little work has been carried out to investigate exposure determinants such as drilling fluid viscosity and temperature. A study was undertaken to investigate the effect of two different oil-based drilling fluid systems and their temperature on oil mist, oil vapour, and total volatile organic compounds (TVOC) levels in a simulated shale shaker room at a purpose-built test centre. Oil mist and oil vapour concentrations were sampled simultaneously using a sampling arrangement consisting of a Millipore closed cassette loaded with glass fibre and cellulose acetate filters attached to a backup charcoal tube. TVOCs were measured by a PhoCheck photo-ionization detector direct reading instrument. Concentrations of oil mist, oil vapour, and TVOC in the atmosphere surrounding the shale shaker were assessed during three separate test periods. Two oil-based drilling fluids, denoted 'System 2.0' and 'System 3.5', containing base oils with a viscosity of 2.0 and 3.3-3.7 mm(2) s(-1) at 40°C, respectively, were used at temperatures ranging from 40 to 75°C. In general, the System 2.0 yielded low oil mist levels, but high oil vapour concentrations, while the opposite was found for the System 3.5. Statistical significant differences between the drilling fluid systems were found for oil mist (P = 0.025),vapour (P < 0.001), and TVOC (P = 0.011). Increasing temperature increased the oil mist, oil vapour, and TVOC levels. Oil vapour levels at the test facility exceeded the Norwegian oil vapour occupational exposure limit (OEL) of 30 mg m(-3) when the drilling fluid temperature was ≥50°C. The practice of testing compliance of oil vapour exposure from drilling fluids systems containing base oils with viscosity of ≤2.0 mm(2) s(-1) at 40

  12. 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.

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

    SciTech Connect

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

    1987-09-01

    The suitability of a synthetic copolymer for drilling deep, hot wells was demonstrated through laboratory and field testing. The polymer provided fluid-loss control at 400/sup 0/F (204/sup 0/C) to clay-free saturated-salt laboratory muds and to low-solids, nondispersed field muds contaminated with drill solids and sodium and calcium salts. High-temperature/high-pressure (HTHP) filtrate was kept at less than or equal to 15 cm/sup 3//30 min after 400/sup 0/F (204/sup 0/C) heat-aging of a 19-lbm/gal (2277-kg/m/sup 3/) saturated-salt mud. Weighted (> 18-lbm/gal (>2157-kg/m/sup 3/)) potassium muds treated with the polymer showed heat stability and solids and green-cement tolerance. The polymer was successfully field-tested in two offshore wells where bottomhole temperatures (BHT's) reached 400/sup 0/F (204/sup 0/C) and salt and calcium chloride flows were encountered.

  14. 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.

  15. A new tool for palaeoclimate reconstruction: Noble gas temperatures from fluid inclusions in speleothems

    NASA Astrophysics Data System (ADS)

    Kluge, T.; Marx, T.; Scholz, D.; Niggemann, S.; Mangini, A.; Aeschbach-Hertig, W.

    2008-05-01

    The aim of our research is to apply the absolute palaeothermometer provided by dissolved noble gases in water to the reliably dated high-resolution archive of speleothems. Here we report on methods used to extract and quantify water and noble gases from fluid inclusions in speleothems and the first successful derivation of noble gas temperatures (NGTs) from this archive. The water amount was determined manometrically, whereas the low noble gas amounts were measured by mass spectrometry, applying rigorous blank control. Gas was extracted by crushing either in a steel cylinder or in a copper tube with little heating, which both yielded acceptably low blanks. Extraction in the steel cylinder is more efficient as a finer grain size distribution can be achieved. A major problem is the often high contribution of noble gases from air inclusions, masking the temperature information present in the noble gases dissolved in water-filled inclusions. However, NGTs with an uncertainty in the range of 1 °C can be derived from suitable stalagmites with low air/water ratios in the inclusions. Such favourable conditions were found to be present in stalagmites of milky white appearance. Suitable samples were collected from the stalagmites BU-U, BU-1 and a soda straw from the Bunker Cave in North-West Germany. Inverse modeling of measured Ne, Ar, Kr, and Xe concentrations leads to a mean temperature of (2.9 ± 0.7) °C for all BU-U sub-samples with an age between 10 800 and 11 700 years and of (7.1 ± 0.8) °C for a 1300 years old sample from BU-1. Compared to the modern mean annual air temperature at the investigated site of about 9.5 °C, the calculated temperatures appear rather low but not unreasonable, as the ages correspond to comparatively cool periods around the Younger Dryas/Preboreal transition and the Early Middle Ages, respectively. Moreover, the indicated temperature difference of about 4 °C between the early and late Holocene periods is in agreement with expectations.

  16. 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.

  17. Preferential dissolution of SiO2 from enstatite to H2 fluid under high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Shinozaki, Ayako; Kagi, Hiroyuki; Hirai, Hisako; Ohfuji, Hiroaki; Okada, Taku; Nakano, Satoshi; Yagi, Takehiko

    2016-04-01

    Stability and phase relations of coexisting enstatite and H2 fluid were investigated in the pressure and temperature regions of 3.1-13.9 GPa and 1500-2000 K using laser-heated diamond-anvil cells. XRD measurements showed decomposition of enstatite upon heating to form forsterite, periclase, and coesite/stishovite. In the recovered samples, SiO2 grains were found at the margin of the heating hot spot, suggesting that the SiO2 component dissolved in the H2 fluid during heating, then precipitated when its solubility decreased with decreasing temperature. Raman and infrared spectra of the coexisting fluid phase revealed that SiH4 and H2O molecules formed through the reaction between dissolved SiO2 and H2. In contrast, forsterite and periclase crystals were found within the hot spot, which were assumed to have replaced the initial orthoenstatite crystals without dissolution. Preferential dissolution of SiO2 components of enstatite in H2 fluid, as well as that observed in the forsterite H2 system and the quartz H2 system, implies that H2-rich fluid enhances Mg/Si fractionation between the fluid and solid phases of mantle minerals.

  18. Determining majors fluid-flow zones in a geothermal sandstone reservoir from thermal conductivity and temperature logs

    NASA Astrophysics Data System (ADS)

    Haffen, S.; Géraud, Y.; Diraison, M.; Dezayes, C.

    2012-04-01

    A method, based on thermal gradient analysis, is presented for locating hot fluid flow in a rock formation. The method involves determining the thermal gradient from thermal conductivity measurements on core samples and also from borehole temperature logs run in the same borehole. With a heat flow density calculation and thermal conductivity measurements, one can apply Fourier's law to calculate the thermal gradient in a rock system where the heat transfer is assumed to be controlled only by conduction. The thermal gradient calculated from a measured temperature log profile takes into account both the conductive and the convective or advective part due to fluid circulation. On the one hand, if the thermal gradient deduced from temperature logs indicates similar values to the thermal gradient calculated with Fourier's law, the heat transfer is assumed to be controlled solely by conduction in the rock formation and thus involves no relative hot or cold fluid circulation. If, on the other hand, the thermal gradient deduced from the temperature logs indicates higher or lower values than that calculated with Fourier's law, then respectively hot or cold fluid flow could be suspected. We applied this method to borehole EPS1 (Soultz-sous-Forêts, Upper Rhine Graben) for which temperature logs and core samples from the Buntsandstein are available. Variations between the two determined thermal gradient curves revealed three main hot fluid flow levels alternating with non-flow zones in the sandstone formation. The pattern was then compared against the fracture distribution, and also against sedimentological analyses determined from the borehole cores, in order to determine the driving components of the fluid flows. The flow zones in the Buntsandstein are controlled on the one hand by a macroscopic network with two major fault zones providing a flow path for the deep heat source and on the other hand by a matrix network formed during sedimentary or diagenetic processes within

  19. a Numerical Study on the Magnetic Fluid Flow in a Channel Surrounding a Permanent Magnet Under Temperature Field

    NASA Astrophysics Data System (ADS)

    Li, X. L.; Yao, K. L.; Liu, Z. L.

    It was investigated that the magnetic fluid which can be the carrier of magnetic particles or magnetic drug carrier particles (MDCP) flows surrounding a permanent magnet in a channel under the influence of high gradient magnetic field and the temperature difference between upper and lower boundaries of the channel. It is considered that the magnetization of the fluid varies linearly with temperature and magnetic field intensity. The numerical solution of above model is described by a coupled and nonlinear system of PDEs. Results indicate that the presence of magnetic and temperature fields appreciably influence the flow field; vortexes arise almost around the magnetic source and also appear near the upper left and lower right boundaries. The temperature, local skin friction coefficient and rate of heat transfer are all affected by the magnitude and position of the magnetic source, they fluctuate evidently near the high gradient magnetic field area.

  20. The solubility of rocks in metamorphic fluids: A model for rock-dominated conditions to upper mantle pressure and temperature

    NASA Astrophysics Data System (ADS)

    Galvez, Matthieu E.; Manning, Craig E.; Connolly, James A. D.; Rumble, Douglas

    2015-11-01

    Fluids exert a key control on the mobility of elements at high pressure and temperature in the crust and mantle. However, the prediction of fluid composition and speciation in compositionally complex fluid-rock systems, typically present in subduction zones, has been hampered by multiple challenges. We develop a computational framework to study the role of phase equilibria and complex solid-solutions on aqueous fluid speciation in equilibrium with rocks to 900 °C and 3 GPa. This is accomplished by merging conventional phase-equilibrium modeling involving electrolyte-free molecular fluids, with an electrostatic approach to model solute-solute and solute-solvent interactions in the fluid phase. This framework is applied to constrain the activity ratios, composition of aqueous solutes, and pH of a fluid in equilibrium with a pelite lithology. Two solvent compositions are considered: pure H2O, and a COH fluid generated by equilibration of H2O and graphite. In both cases, we find that the pH is alkaline. Disparities between the predicted peralkalinity of our fluid ([Na ] + [K ]) / [Al ] ∼ 6 to 12 and results from independent mineral solubility experiments (∼2) point to the presence of Na-K-Al-Si polymers representing ca. 60 to 85% of the total K and Al content of the fluid at 600 °C and 2.2 GPa, and to an important fraction of dissolved Ca and Mg not accounted for in present speciation models. The addition of graphite to the system reduces the relative permittivity by ca. 40% at elevated T and low P, triggers the formation of C-bearing anions, and brings the pH closer to neutrality by up to 0.6 units at low T. This ionic C pool represents up to 45 mol% of the fluid ligands at elevated P, and is dominant at low P despite the low ionic strength of the fluid (<0.05). The present study offers new possibilities for exploring redox- pH dependent processes that govern volatile, major and trace element partitioning between rocks and fluids in experimental or natural

  1. 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.

  2. Fluid chemistry of the low temperature hyperalkaline hydrothermal system of Prony Bay (New Caledonia)

    NASA Astrophysics Data System (ADS)

    Monnin, C.; Chavagnac, V.; Boulart, C.; Ménez, B.; Gérard, M.; Gérard, E.; Pisapia, C.; Quéméneur, M.; Erauso, G.; Postec, A.; Guentas-Dombrowski, L.; Payri, C.; Pelletier, B.

    2014-10-01

    The terrestrial hyperalkaline springs of Prony Bay (southern lagoon, New Caledonia) have been known since the nineteenth century, but a recent high-resolution bathymetric survey of the seafloor has revealed the existence of numerous submarine structures similar to the well-known Aiguille de Prony, which are also the location of high-pH fluid discharge into the lagoon. During the HYDROPRONY cruise (28 October to 13 November 2011), samples of waters, gases and concretions were collected by scuba divers at underwater vents. Four of these sampling sites are located in Prony Bay at depths up to 50 m. One (Bain des Japonais spring) is also in Prony Bay but uncovered at low tide and another (Rivière des Kaoris spring) is on land slightly above the seawater level at high tide. We report the chemical composition (Na, K, Ca, Mg, Cl, SO4, dissolved inorganic carbon, SiO2(aq)) of 45 water samples collected at six sites of high-pH water discharge, as well as the composition of gases. Temperatures reach 37 °C at the Bain des Japonais and 32 °C at the spring of the Kaoris. Gas bubbling was observed only at these two springs. The emitted gases contain between 12 and 30% of hydrogen in volume of dry gas, 6 to 14% of methane, and 56 to 72% of nitrogen, with trace amounts of carbon dioxide, ethane and propane. pH values and salinities of all the 45 collected water samples range from the seawater values (8.2 and 35 g L-1) to hyperalkaline freshwaters of the Ca-OH type (pH 11 and salinities as low as 0.3 g L-1) showing that the collected samples are always a mixture of a hyperalkaline fluid of meteoric origin and ambient seawater. Cl-normalized concentrations of dissolved major elements first show that the Bain des Japonais is distinct from the other sites. Water collected at this site are three component mixtures involving the high-pH fluid, the lagoon seawater and the river water from the nearby Rivière du Carénage. The chemical compositions of the hyperalkaline endmembers (at p

  3. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee

    2015-05-01

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B-H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  4. Characteristics of temperature rise in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source

    SciTech Connect

    Lee, Ho-Young; Kang, In Man; Shon, Chae-Hwa; Lee, Se-Hee

    2015-05-07

    A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal characteristics have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the characteristics of temperature rise and developed a numerical analysis technique. The characteristics of temperature rise were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. To improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature rise for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.

  5. Fluid-matrix interactions during high-temperature aquifer storage - lab experiments and modelling

    NASA Astrophysics Data System (ADS)

    Wismeth, Carina; Ueckert, Martina; Muffler, Selina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    High-temperature aquifer storage is a promising extension to combined heat and power plants because it allows to store excess heat during the summer months and to recuperate the heat in winter when the heat demand exceeds the production. Within a research project funded by the Bavarian State Ministry for Economic Affairs and Media, Energy and Technology and the BMW Group, a pilot scale test was run at the Dingolfing site (Bavaria, Germany) in 2014. Field data and an a priori numerical model suggest dissolution and precipitation of the processes in the calcareous aquifer. In order to quantify the reaction kinetics, lab experiments were run in an autoclave. The experimental results were used to setup and calibrate a numerical hydrogeochemical model based on PhreeqC. Laboratory experiments were performed in a closed system with respect to CO2 and under pre-defined conditions using a high temperature autoclave. Within the dissolution test series original core samples of different depth were heated up with ultrapure water in defined heating cycles up to 110 °C and at defined pressure. For combined dissolution and precipitation processes, tap water from Munich was used. The gas phase was equilibrated with CO2 regarding the pCO2 of tap water. Five water samples were taken for each heating cycle and analyzed by ion chromatography to quantify the calcium/magnesium concentrations and ratio. Additionally the sorption properties of the core materials were tested with respect to the fluorescent dyes used in the field tests. The starting point to model the fluid matrix interactions was literature data of dolomite and calcite rates, which were integrated in the conceptional model. While the model results matched the experimentally determined concentrations nicely, there was a discrepancy with respect to the effective surface areas, which is likely due to impurities of the natural rock materials. The model was able to describe the minor precipitation of calcite during the

  6. Solid-to-fluid DNA transition inside HSV-1 capsid close to the temperature of infection

    SciTech Connect

    Sae-Ueng, Udom; Li, Dong; Zuo, Xiaobing; Huffman, Jamie B.; Homa, Fred L.; Rau, Donald; Evilevitch, Alex

    2014-10-01

    DNA in the human Herpes simplex virus type 1 (HSV-1) capsid is packaged to a tight density. This leads to tens of atmospheres of internal pressure responsible for the delivery of the herpes genome into the cell nucleus. In this study we show that, despite its liquid crystalline state inside the capsid, the DNA is fluid-like, which facilitates its ejection into the cell nucleus during infection. We found that the sliding friction between closely packaged DNA strands, caused by interstrand repulsive interactions, is reduced by the ionic environment of epithelial cells and neurons susceptible to herpes infection. However, variations in the ionic conditions corresponding to neuronal activity can restrict DNA mobility in the capsid, making it more solid-like. This can inhibit intranuclear DNA release and interfere with viral replication. In addition, the temperature of the human host (37 °C) induces a disordering transition of the encapsidated herpes genome, which reduces interstrand interactions and provides genome mobility required for infection.

  7. Exact analytical solution to a transient conjugate heat-transfer problem

    NASA Technical Reports Server (NTRS)

    Sucec, J.

    1973-01-01

    An exact analytical solution is found for laminar, constant-property, slug flow over a thin plate which is also convectively cooled from below. The solution is found by means of two successive Laplace transformations when a transient in the plate and the fluid is initiated by a step change in the fluid inlet temperature. The exact solution yields the transient fluid temperature, surface heat flux, and surface temperature distributions. The results of the exact transient solution for the surface heat flux are compared to the quasi-steady values, and a criterion for the validity of the quasi-steady results is found. Also the effect of the plate coupling parameter on the surface heat flux are investigated.

  8. A Transient Heat Transfer Model for Assessment of Flash Temperature During Dry Sliding Wear in a Pin-on-Disk Tribometer

    NASA Astrophysics Data System (ADS)

    Mondal, Manas Kumar; Biswas, Koushik; Maity, Joydeep

    2016-01-01

    In this research work, an analytical transient heat transfer model has been proposed for measurement of flash temperature in a pin-on-disk tribometer in view of the variation in coefficient of friction (dependent on wear mechanism). The model was successfully validated with experimental results of the present research work as well as with reported experimental data. The model also suggested a rise in flash temperature to a high level [441 K (168 °C)] resulting in an evolution of nodular oxide (Al2O3) that eventually reduced the wear loss to a considerable extent.

  9. Natural convection of a magnetic fluid in a cubic enclosure

    NASA Astrophysics Data System (ADS)

    Kikura, H.; Sawada, T.; Tanahashi, T.

    1993-04-01

    Laminar natural convection heat transfer of a magnetic fluid in a cubic enclosure is examined experimentally. Wall-temperature distributions are visualized by thermosensitive liquid crystal sheets. The effect of the magnetic field on the transient temperature distributions, and the local and averaged Nusselt numbers are discussed.

  10. Syn-deformation temperature and fossil fluid pathways along an exhumed detachment zone, khao khwang fold-thrust belt, Thailand

    NASA Astrophysics Data System (ADS)

    Hansberry, Rowan L.; Collins, Alan S.; King, Rosalind C.; Morley, Christopher K.; Giże, Andy P.; Warren, John; Löhr, Stefan C.; Hall, P. A.

    2015-08-01

    Shale detachment zones, their influence on deformational style, and their internal mechanisms of deformation are an understudied aspect of fold-thrust belts. Properties such as deformational temperature, lithology, and mineralogy are often recognized as having a key influence on the rheology and deformational style of detachment zones and overlying fold-thrust belts. However, little work has been conducted on rock properties of known detachment zones. A recently described upper-level detachment zone in the exhumed Khao Khwang Fold-Thrust Belt of central Thailand provides an ideal natural laboratory for investigation of the deformation conditions of the detachment zone, and association with its complex deformational style. The low-grade metamorphic indicator illite crystallinty is used to broadly constrain deformational temperatures, while oxygen and carbon stable isotope analysis provides insight into fluid flow history and fluid-rock interaction. Illite crystallinity data indicate deep diagenetic, to low anchizonal conditions, and temperatures of ~ 160-210 °C in the shale detachment, interpreted as reflecting peak metamorphic conditions during the Triassic Indosinian Orogeny. No trend between the intensity (spacing, complexity) of structures and illite crystallinty is observed. However, shale shear zones of continuous-style deformation and inferred higher finite strain display uniformly higher illite crystallinty than surrounding packages of discontinuously faulted shales. We also note a positive association between total organic carbon content in the shales and the spacing and complexity of deformational structures. Data from limestones and syn-tectonic vein fills detail the history of fluid-rock interaction during early mesogenesis, through to orogenesis. The early covariant trend of increasingly negative δ13C and δ18O values is attributed to increasing burial, while a divergent orogenic trend of increasingly negative δ18O values is interpreted as the result

  11. A theory for the retrieval of virtual temperature from winds, radiances and the equations of fluid dynamics

    NASA Technical Reports Server (NTRS)

    Tzvi, G. C.

    1986-01-01

    A technique to deduce the virtual temperature from the combined use of the equations of fluid dynamics, observed wind and observed radiances is described. The wind information could come from ground-based sensitivity very high frequency (VHF) Doppler radars and/or from space-borne Doppler lidars. The radiometers are also assumed to be either space-borne and/or ground-based. From traditional radiometric techniques the vertical structure of the temperature can be estimated only crudely. While it has been known for quite some time that the virtual temperature could be deduced from wind information only, such techniques had to assume the infallibility of certain diagnostic relations. The proposed technique is an extension of the Gal-Chen technique. It is assumed that due to modeling uncertainties the equations of fluid dynamics are satisfied only in the least square sense. The retrieved temperature, however, is constrained to reproduce the observed radiances. It is shown that the combined use of the three sources of information (wind, radiances and fluid dynamical equations) can result in a unique determination of the vertical temperature structure with spatial and temporal resolution comparable to that of the observed wind.

  12. Characterizing the Effect of Temperature and Magnetic Field Strengths on the Complex Shear Modulus Properties of Magnetorheological (mr) Fluids

    NASA Astrophysics Data System (ADS)

    Chooi, W. W.; Oyadiji, S. O.

    When a magnetic field is applied across MR fluids, a yield stress is developed, and their rheological properties can then be categorized into two distinct regimes; pre-yield and post-yield. This paper concerns the viscoelastic behaviour of MR fluids in the pre-yield region. Oscillatory tests were carried out to determine the complex shear modulus properties of MR fluids between the temperature range of -20°C and +50°C. The test results show that the storage modulus and loss modulus increased in value as the excitation frequency was increased from 5Hz to 50Hz. The complex modulus was also found to be influenced by changes in temperature; the higher the temperature, the lower the complex modulus. This is consistent with the behaviour of viscoelastic polymers. The sets of temperature-dependent and frequency-dependent data were subsequently condensed using the method of reduced variables into master curves of complex modulus which effectively extended the frequency coverage of the data at the reference temperature.

  13. Fluid-inclusion technique for determining maximum temperature in calcite and its comparison to the vitrinite reflectance geothermometer

    USGS Publications Warehouse

    Barker, C.E.; Goldstein, R.H.

    1990-01-01

    The hypothesis that aqueous fluid inclusions in calcite can be used to establish maximum temperature (Tpeak) is tested. Fluid inclusion Th, mean random vitrinite reflectance (Rm), and present-day Tpeak from 46 diverse geologic systems that have been at Tpeak from 104 to 106 yr have been compiled. Present Tpeak ranged from 65 to 345??C, Th modes and means ranged from 59 to 350??C, and Rm data ranged from 0.4% to 4.6%, spanning the temperature and thermal maturity range associated with burial diagenesis, hydrothermal alteration, and low-grade metamorphism. Plots of Th and Tpeak data for systems thought to be currently at maximum temperature demonstrate close agreement between Th and present Tpeak in sedimentary basins. The relation suggests that Th of aqueous fluid inclusions in calcite may be a useful measure of maximum temperature. This study also compared Th to mean random vitrinite reflectance (Rm). Th correlates well with Rm and results in a curve similar to Rm vs. Tpeak calibrations determined by other workers. Strong correlation between Tpeak and Rm in these systems suggests that maximum temperature is the major control on thermal maturation. -after Authors

  14. Design of an adaptive control for a magnetorheological fluid brake with model parameters depending on temperature and speed

    NASA Astrophysics Data System (ADS)

    Russo, R.; Terzo, M.

    2011-11-01

    This paper describes experimental/theoretical activities carried out on a magnetorheological fluid brake (MRFB) prototype. A device model is derived and a detailed evaluation of the influence of temperature and speed on its parameters is performed. It can be seen that temperature and speed act as modifying inputs for the system model and change the value of some of its parameters. More specifically, time constant and torque/current gain are affected by velocity whereas fluid viscosity is only affected by temperature. The presence of the above modifying input suggests the employment of an adaptive approach for MRFB feedback control based on the torque measurement only. Starting from the proposed model, a model reference adaptive control is designed, ensuring that the tracking error converges to zero as time t \\to \\infty . Simulation activity, carried out on the device validated model, confirms the effectiveness of the proposed adaptive controller.

  15. Non-linear effects in a spherical convection experiments with temperature dependent fluid properties: Microgravity experiment and numerical simulations

    NASA Astrophysics Data System (ADS)

    Zaussinger, F.; Futterer, B.; Egbers, C.

    2012-12-01

    Thermal convection is one important driving mechanism of flow in the earth mantle. Setting up a self-gravitating buoyancy in a spherical shell geometry is the limiting factor for laboratory experiments to analyze velocity flow structures and heat transport. The geophysical flow model 'GeoFlow II', which is located at the Columbus module on the ISS, realizes such a central gravity. Under microgravity conditions a central dielectrophoretic force field is applied to a fluid filled spherical annulus. In contrast to the first mission 'GeoFlow I' the electro-hydrodynamical volume expansion coefficient of the working fluid has a strong dependence on the temperature and leads to pattern, which are related to a strong temperature dependent viscosity of the fluid. Even though the oil's viscosity itself is temperature-dependent, too, the maximum of viscosity contrast is only up to 1.5. The optical measurement of the fluid flow is based on the Wollaston shearing interferometry, since the on orbit setup avoids the use of measurement particles. This technique leads to fringe patterns. Simulations with RESPECT and GAIAA tend to verify the experimentally observed patterns by different numerical models.

  16. Activity and phylogenetic diversity of sulfate-reducing microorganisms in low-temperature subsurface fluids within the upper oceanic crust

    PubMed Central

    Robador, Alberto; Jungbluth, Sean P.; LaRowe, Douglas E.; Bowers, Robert M.; Rappé, Michael S.; Amend, Jan P.; Cowen, James P.

    2015-01-01

    The basaltic ocean crust is the largest aquifer system on Earth, yet the rates of biological activity in this environment are unknown. Low-temperature (<100°C) fluid samples were investigated from two borehole observatories in the Juan de Fuca Ridge (JFR) flank, representing a range of upper oceanic basement thermal and geochemical properties. Microbial sulfate reduction rates (SRR) were measured in laboratory incubations with 35S-sulfate over a range of temperatures and the identity of the corresponding sulfate-reducing microorganisms (SRM) was studied by analyzing the sequence diversity of the functional marker dissimilatory (bi)sulfite reductase (dsrAB) gene. We found that microbial sulfate reduction was limited by the decreasing availability of organic electron donors in higher temperature, more altered fluids. Thermodynamic calculations indicate energetic constraints for metabolism, which together with relatively higher cell-specific SRR reveal increased maintenance requirements, consistent with novel species-level dsrAB phylotypes of thermophilic SRM. Our estimates suggest that microbially-mediated sulfate reduction may account for the removal of organic matter in fluids within the upper oceanic crust and underscore the potential quantitative impact of microbial processes in deep subsurface marine crustal fluids on marine and global biogeochemical carbon cycling. PMID:25642212

  17. Effects of fluid medium flow and spatial temperature variation on acoustophoretic motion of microparticles in microfluidic channels.

    PubMed

    Liu, Zhongzheng; Kim, Yong-Joe; Wang, Han; Han, Arum

    2016-01-01

    A numerical modeling method for accurately predicting the acoustophoretic motion of compressible microparticles in microfluidic devices is presented to consider the effects of fluid medium flow and spatial temperature variation that can significantly influence the acoustophoretic motion. In the proposed method, zeroth-order fluid medium flow and temperature, and first- and second-order acoustic fields in the microfluidic devices are first calculated by applying quadratic mapping functions and a second-order finite difference method (FDM) to perturbed mass, momentum, and energy conservation equations and state equation. Then, the acoustic radiation force is obtained based on the Gorkov's acoustic radiation force equation and applied to the Newton's Equation of Motion to calculate the microparticle motion. The proposed method was validated by comparing its results to a commercial software package, COMSOL Multiphysics results, one-dimensional, analytical modeling results, and experimental results. It is shown that the fluid medium flow affects the acoustic radiation force and streaming significantly, resulting in the acoustic radiation force and streaming prediction errors of 10.9% and 67.4%, respectively, when the fluid medium flow speed is increased from 0 to 1 m/s. A local temperature elevation from 20 °C to 22 °C also results in the prediction errors of 88.4% and 73.4%. PMID:26827029

  18. Pt and Pt-Ru/Carbon Nanotube Nanocomposites Synthesized in Supercritical Fluid as Electrocatalysts for Low-Temperature Fuel Cells

    SciTech Connect

    Lin, Yuehe; Cui, Xiaoli; Wang, Jun; Yen, Clive; Wai, Chien M.

    2006-06-01

    In recent years, the use of supercritical fluids (SCFs) for the synthesis and processing of nanomaterials has proven to be a rapid, direct, and clean approach to develop nanomaterials and nanocomposites. The application of supercritical fluid technology can result in products (and processes) that are cleaner, less expensive, and of higher quality than those that are produced using conventional technologies and solvents. In this work, carbon nanotube (CNT)-supported Pt and Pt-Ru nanoparticles catalysts have been synthesized in supercritical carbon dioxide (scCO2). The experimental results demonstrate that Pt, Pt-Ru/CNT nanocomposites synthesized in supercritical carbon dioxide are effective electrocatalysts for low-temperature fuel cells.

  19. 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.

  20. Effect of simulated pulpal fluid circulation on intrapulpal temperature following irradiation with an Nd:YVO4 laser.

    PubMed

    Braun, Andreas; Kecsmar, Susann; Krause, Felix; Berthold, Michael; Frentzen, Matthias; Frankenberger, Roland; Schelle, Florian

    2015-05-01

    It is suggested that pulpal fluid circulation has an impact on pulp temperature increase during heat-generating dental treatment procedures. Thus, the aim of the study was to assess the effect of a simulated pulpal fluid circulation on temperature changes inside the pulp chamber following laser irradiation of the tooth surface. Twenty freshly extracted human multirooted teeth were included and cross-sectioned along the long axis exposing two root canals each. The pulp chamber and root canals were cleaned from remaining soft tissues to achieve access for a temperature sensor and two cannulas to allow fluid circulation. Cross sections were glued together, and the roots were encased with silicone impression material to ensure the position of the connected devices. Each tooth was irradiated by employing a neodymium-doped yttrium orthovanadate (Nd:YVO4) laser at 1,064 nm with a pulse duration of 9 ps and a repetition rate of 500 kHz. A commercially available scanning system (SCANcube 7, SCANLAB) deflected the beam by providing rectangular irradiated areas of 0.5 mm edge length. Measurements were performed with four different settings for fluid circulation: without any water and with water (23 °C) at a flow rate of 6, 3, and 0 ml/min. The primary outcome measure was the maximum temperature difference (ΔT) after laser irradiation. Highest temperature changes (median 3.6 K, range 0.5-7.1 K) could be observed without any fluid inside the pulp chamber. Water without circulation decreased ΔT values statistically significantly (median 1.4 K, range 0.2-4.9 K) (p < 0.05). Lowest temperature changes could be observed with a water flow rate of 6 ml/min (median 0.8 K, range 0.2-3.7 K) (p < 0.05). Pulpal fluid circulation has a cooling effect on temperature increase caused by laser irradiation of dental hard tissues. Studies on heat generation during dental treatment procedures should include this aspect to assess a potential thermal injury of pulp tissue. PMID:24578013

  1. Analysis of transient thermal stress in heat-generating plates and hollow cylinders caused by sudden environmental temperature changes

    NASA Technical Reports Server (NTRS)

    Rosenberg, G. S.; Schoeberle, D. F.; Valentin, R. A.

    1969-01-01

    Analysis and solution are presented for transient thermal stresses in a free heat-generating flat plate and a free, hollow-generating cylinder as a result of sudden environmental changes. The technique used and graphical results obtained are of interest to the heat transfer industry.

  2. Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes.

    PubMed

    Weis, P; Driesner, T; Heinrich, C A

    2012-12-21

    Porphyry-type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can stabilize a front of metal precipitation at the boundary between lithostatically pressured up-flow of hot magmatic fluids and hydrostatically pressured convection of cooler meteoric fluids. The balance between focused heat advection and lateral cooling controls the most important economic characteristics, including size, shape, and ore grade. This self-sustaining process may extend to epithermal gold deposits, venting at active volcanoes, and regions with the potential for geothermal energy production. PMID:23160957

  3. Preliminary studies of coolant by-pass flows in a prismatic very high temperature reactor using computational fluid dynamics

    SciTech Connect

    Hiroyuki Sato; Richard Johnson; Richard Schultz

    2009-09-01

    Three dimensional computational fluid dynamic (CFD) calculations of a typical prismatic very high temperature gas-cooled reactor (VHTR) were conducted to investigate the influence of gap geometry on flow and temperature distributions in the reactor core using commercial CFD code FLUENT. Parametric calculations changing the gap width in a whole core length model of fuel and reflector columns were performed. The simulations show the effects of core by-pass flows in the heated core region by comparing results for several gap widths including zero gap width. The calculation results underline the importance of considering inter-column gap width for the evaluation of maximum fuel temperatures and temperature gradients in fuel blocks. In addition, it is shown that temperatures of core outlet flow from gaps and channels are strongly affected by the gap width of by-pass flow in the reactor core.

  4. Investigation of the temperature dependence of the optical properties of thermal transfer fluids for hybrid CPV-T systems

    NASA Astrophysics Data System (ADS)

    Wu, Yiliang; Everett, Vernie; Thomsen, Elizabeth; Blakers, Andrew

    2013-09-01

    This study investigates the influence of temperature on the spectral absorption characteristics of three heat transfer fluids; propylene glycol, mineral oil, and silicone oil. The region of interest of the liquid absorption spectra ranges from 700 to 2000 nm. The absorbance of propylene glycol was found to have a strong dependence on temperature. Mineral oil and silicone oil did not present significant temperature dependent absorbance. Absorbance peaks for water were found at 750, 985 1175, 1285 and 1680 nm. Propylene glycol also showed absorbance changes in these regions. In addition, propylene glycol displays two other regions of temperature-dependent absorbance. In contrast with silicone oil and mineral oil, the hydroxyl bond is only present in water and propylene glycol. It is thought that resonant absorption of the hydroxyl bond is responsible for the measured temperature-dependent absorption change.

  5. Culture of dialysis fluids on nutrient-rich media for short periods at elevated temperatures underestimate microbial contamination.

    PubMed

    Pass, T; Wright, R; Sharp, B; Harding, G B

    1996-01-01

    Recommended culture methods for monitoring bacterial contamination of H2O, dialysate and bicarbonate concentrate in dialysis centers in the USA involves culturing these fluids for 48 h at 37 degrees C. A variety of media and commercial culture methods are accepted for monitoring these fluids. Over a 3-month a comparison was made between an acceptable culture method, tryptic soy agar (TSA) employing the pour plate (PP) technique at 37 degrees C for 48 h, and PP cultures on standard methods agar (SMA) and R2A agar, incubated at ambient temperature (23 degrees C) for 48, 72, 168 h. Increases in the colony counts over time occurred for all three fluids. However, counts wee greater on SMA and R2A than on TSA. The increases over the standard 48-hour TSA cultures ranged as high as 10(4) times for 23 degrees C cultures at 7 days of incubation. Endotoxin levels even in the most contaminated samples were found to be below the acceptable 5 EU/ml recommended for reprocessor water. Bacterial colonies that appeared at 48, 72 and 168 h were isolated and identified. Pseudomonas, Moraxella, Acinetobacter and CDC group VI C-2 were among some of the common bacteria isolated. This study indicates that the media utilized, the time and temperature of incubation may result in a significant underestimation of the bacterial population of water and dialysis fluids, thus potentially placing the patient at a higher risk. PMID:8785029

  6. Documentation and verification of VST2D; a model for simulating transient, Variably Saturated, coupled water-heat-solute Transport in heterogeneous, anisotropic 2-Dimensional, ground-water systems with variable fluid density

    USGS Publications Warehouse

    Friedel, Michael J.

    2001-01-01

    This report describes a model for simulating transient, Variably Saturated, coupled water-heatsolute Transport in heterogeneous, anisotropic, 2-Dimensional, ground-water systems with variable fluid density (VST2D). VST2D was developed to help understand the effects of natural and anthropogenic factors on quantity and quality of variably saturated ground-water systems. The model solves simultaneously for one or more dependent variables (pressure, temperature, and concentration) at nodes in a horizontal or vertical mesh using a quasi-linearized general minimum residual method. This approach enhances computational speed beyond the speed of a sequential approach. Heterogeneous and anisotropic conditions are implemented locally using individual element property descriptions. This implementation allows local principal directions to differ among elements and from the global solution domain coordinates. Boundary conditions can include time-varying pressure head (or moisture content), heat, and/or concentration; fluxes distributed along domain boundaries and/or at internal node points; and/or convective moisture, heat, and solute fluxes along the domain boundaries; and/or unit hydraulic gradient along domain boundaries. Other model features include temperature and concentration dependent density (liquid and vapor) and viscosity, sorption and/or decay of a solute, and capability to determine moisture content beyond residual to zero. These features are described in the documentation together with development of the governing equations, application of the finite-element formulation (using the Galerkin approach), solution procedure, mass and energy balance considerations, input requirements, and output options. The VST2D model was verified, and results included solutions for problems of water transport under isohaline and isothermal conditions, heat transport under isobaric and isohaline conditions, solute transport under isobaric and isothermal conditions, and coupled water

  7. High-temperature air/steam-blown gasification of coal in a pressurized spout-fluid bed

    SciTech Connect

    Rui Xiao; Mingyao Zhang; Baosheng Jin; Yaji Huang; Hongcang Zhou

    2006-03-15

    The concept of high-temperature air/steam-blown gasification technology for converting coal into low-caloric-value gas for power generation is proposed and evaluated experimentally. Preliminary experiments are performed in a 0.1 MW thermal input pressurized spout-fluid bed gasifier. The influences of the gasifying agent preheat temperature, the gasification temperature and pressure, the equivalence ratio, the ratio of steam-to-coal on gas composition, gas higher heating value, carbon conversion, and cold gas efficiency are examined. The experimental results prove the feasibility of high-temperature air/steam-blown gasification process. The gas heating value is increased by 23%, when the gasifying agent temperature is increased from 300 to 700 C. For the operation conditions studied, the results show that gasification temperature is the most important factor influencing coal gasification in the spout-fluid bed. The gasifier performance is improved at elevated pressure mainly due to the better fluidization in the reactor. The operating parameters of the equivalence ratio and the ratio of steam-to-coal exist at optimum operating range for a certain coal gasification process. 21 refs., 10 figs., 4 tabs.

  8. Temperature-dependent study of isotropic nematic transition for a Gay Berne fluid using density-functional theory

    NASA Astrophysics Data System (ADS)

    Singh, Ram Chandra

    2007-09-01

    We have used the density-functional theory to study the effect of varying temperature on the isotropic-nematic transition of a fluid of molecules interacting via the Gay-Berne intermolecular potential. The nematic phase is found to be stable with respect to isotropic phase in the temperature range 0.80<=T*<=1.25. Pair correlation functions needed as input information in density-functional theory is calculated using the Percus-Yevick integral equation theory. We find that the density-functional theory is good for studying the isotropic-nematic transition in molecular fluids if the values of the pair-correlation functions in the isotropic phase are known accurately. We have also compared our results with computer simulation results wherever they are available.

  9. Temperature in a J47-25 Turbojet-engine Combustor and Turbine Sections During Steady-state and Transient Operation in a Sea-level Test Stand

    NASA Technical Reports Server (NTRS)

    Morse, C R; Johnston, J R

    1955-01-01

    In order to determine the conditions of engine operation causing the most severe thermal stresses in the hot parts of a turbojet engine, a J47-25 engine was instrumented with thermocouples and operated to obtain engine material temperatures under steady-state and transient conditions. Temperatures measured during rated take-off conditions of nozzle guide vanes downstream of a single combustor differed on the order of 400 degrees F depending on the relation of the blades position to the highest temperature zone of the burner. Under the same operation conditions, measured midspan temperatures in a nozzle guide vane in the highest temperature zone of a combustor wake ranged from approximately 1670 degrees F at leading and trailing edges to 1340 degrees F at midchord on the convex side of the blade. The maximum measured nozzle-guide-vane temperature of 1920degrees at the trailing edge occurred during a rapid acceleration from idle to rated take-off speed following which the tail-pipe gas temperature exceeded maximum allowable temperature by 125 degrees F.

  10. Oxygen isotope exchange in rocks and minerals from the Cerro Prieto geothermal system: Indicators of temperature distribution and fluid flow

    SciTech Connect

    Williams, A.E.; Elders, W.A.

    1981-01-01

    Oxygen isotopic compositions have been measured in drill cuttings and core samples from more than 40 wells ranging in depth to more than 3.5 km in the Cerro Prieto geothermal field. Profiles of isotopic ratios versus sampling depths provide information on the three-dimensional distribution of temperature and fluid flow. These parameters also indicate variations in the history of hydrothermal processes in different areas of the geothermal field.

  11. Fluid convection observed from temperature logs in the karst formation of the Yucatán Peninsula, Mexico

    NASA Astrophysics Data System (ADS)

    Safanda, Jan; Heidinger, Philipp; Wilhelm, Helmut; Cermák, Vladimir

    2005-12-01

    Temperature-depth profiles, obtained during three campaigns of temperature logging in boreholes of the Yucatán Peninsula in the period 2002-2004, display the effects of thermal fluid convection. These effects are most pronounced in the uppermost part of the 1.5 km deep borehole Yaxcopoil-1 drilled within the Chicxulub impact crater. The convective zone is clearly discernible in all three profiles measured here in March 2002, May 2003 and February 2004. The loggings have revealed a gradual downward propagation of the convective features from the uppermost 145 m of the temperature profile to 230 m between the first and second loggings (with a propagation rate of 6 m/month) and to 265 m between the second and third loggings (4 m/month). A signature of the fluid convection is also evident in all other temperature logs in the area measured during the 2003 campaign, namely in four UNAM boreholes 2, 5, 7 and 8, three hydrogeological boreholes 1A, 1B and 1C, in a borehole at the meteorological observatory Mérida and in the cenote Ucil. The fresh/salt water interface is clearly visible in most of the logs as a zone of increased temperature gradient. The varying intensity of the convective features among the individual logs seems to be correlated with the borehole position relative to the impact structure.

  12. Optimization of Transient Heat Exchanger Performance for Improved Energy Efficiency

    NASA Astrophysics Data System (ADS)

    Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Wirz, Richard

    2014-11-01

    Heat exchangers are used in a multitude of applications within systems for energy generation, energy conversion, or energy storage. Many of these systems (e.g. solar power plants) function under transient conditions, but the design of the heat exchangers is typically optimized assuming steady state conditions. There is a potential for significant energy savings if the transient behavior of the heat exchanger is taken into account in designing the heat exchanger by optimizing its operating conditions in relation to the transient behavior of the overall system. The physics of the transient behavior of a heat exchanger needs to be understood to provide design parameters for transient heat exchangers to deliver energy savings. A numerical model was used to determine the optimized mass flow rates thermal properties for a thermal energy storage system. The transient behavior is strongly linked to the dimensionless parameters relating fluid properties, the mass flow rates, and the temperature of the fluids at the inlet of each stream. Smart metals, or advanced heat exchanger surface geometries and methods of construction will be used to meet the three goals mentioned before: 1) energy and cost reduction, 2) size reduction, and 3) optimal performance for all modes of operation.

  13. Improved fluid dynamics similarity, analysis and verification. Part 5: Analytical and experimental studies of thermal stratification phenomena

    NASA Technical Reports Server (NTRS)

    Winter, E. R. F.; Schoenhals, R. J.; Haug, R. I.; Libby, T. L.; Nelson, R. N.; Stevenson, W. H.

    1968-01-01

    The stratification behavior of a contained fluid subjected to transient free convection heat transfer was studied. A rectangular vessel was employed with heat transfer from two opposite walls of the vessel to the fluid. The wall temperature was increased suddenly to initiate the process and was then maintained constant throughout the transient stratification period. Thermocouples were positioned on a post at the center of the vessel. They were adjusted so that temperatures could be measured at the fluid surface and at specific depths beneath the surface. The predicted values of the surface temperature and the stratified layer thickness were found to agree reasonably well with the experimental measurements. The experiments also provided information on the transient centerline temperature distribution and the transient flow distribution.

  14. Temperature and volume estimation of under-seafloor fluid from the logging-while-drilling data beneath an active hydrothermal field

    NASA Astrophysics Data System (ADS)

    Hamada, Y.; Saito, S.; Sanada, Y.; Masaki, Y.; Moe, K.; Kido, Y. N.; Kumagai, H.; Takai, K.; Suzuki, K.

    2015-12-01

    In July of 2014, offshore drillings on Iheya-North Knoll, Okinawa Trough, was executed as part of Next-generation technology for ocean resources survey, which is a research program in Cross-ministerial Strategic Innovation Promotion Program (SIP). In this expedition, logging-while- drilling (LWD) and measuring-while-drilling (MWD) were inserted into 6 holes (C9011 - C9016) to investigate spatial distribution of hydrothermal deposit and geothermal fluid reservoir. Both of these tools included annular pressure-while-drilling (APWD). Annular pressure and temperature were monitored by the APWD to detect possible exceedingly-high-temperature geofluid. In addition, drilling fluid was continuously circulated at sufficient flow rate to protect LWD tools against high temperature (non-stop driller system). At C9012 and C9016, the LWD tool clearly detected pressure and temperature anomaly at 234 meter below the seafloor (mbsf) and 80 mbsf, respectively. Annular pressure and temperature quickly increases at that depth and it would reflect the injection of high-temperature fluid. During the drilling, however, drilling water was continuously circulated at high flow-rate (2600L/min) and the measured temperature is not exactly in-situ temperature. To investigate the detail of the heat source, such as in-situ temperature and quantity of heat, we performed numerical analyses of thermal fluid and energy-balance assuming injection of high-temperature fluid. We combined pressure loss theory of double cylinders and temperature equation to replicate the fluid flow and its temperature between borehole wall and drilling pipe during the thermofluid injection. As the result, we estimated the temperature and the volume of injected fluid to be 115oC~ and 17.3 m3, respectively (at C9012) from the calculation. This temperature is lower than that of a hydrothermall vent which had been found near the hole (300oC).

  15. A procedure for the transient expression of genes by agroinfiltration above the permissive threshold to study temperature-sensitive processes in plant-pathogen interactions.

    PubMed

    Del Toro, Francisco; Tenllado, Francisco; Chung, Bong-Nam; Canto, Tomas

    2014-10-01

    Localized expression of genes in plants from T-DNAs delivered into plant cells by Agrobacterium tumefaciens is an important tool in plant research. The technique, known as agroinfiltration, provides fast, efficient ways to transiently express or silence a desired gene without resorting to the time-consuming, challenging stable transformation of the host, the use of less efficient means of delivery, such as bombardment, or the use of viral vectors, which multiply and spread within the host causing physiological alterations themselves. A drawback of the agroinfiltration technique is its temperature dependence: early studies have shown that temperatures above 29 °C are nonpermissive to tumour induction by the bacterium as a result of failure in pilus formation. However, research in plant sciences is interested in studying processes at these temperatures, above the 25 °C experimental standard, common to many host-environment and host-pathogen interactions in nature, and agroinfiltration is an excellent tool for this purpose. Here, we measured the efficiency of agroinfiltration for the expression of reporter genes in plants from T-DNAs at the nonpermissive temperature of 30 °C, either transiently or as part of viral amplicons, and envisaged procedures that allow and optimize its use for gene expression at this temperature. We applied this technical advance to assess the performance at 30 °C of two viral suppressors of silencing in agropatch assays [Potato virus Y helper component proteinase (HCPro) and Cucumber mosaic virus 2b protein] and, within the context of infection by a Potato virus X (PVX) vector, also assessed indirectly their effect on the overall response of the host Nicotiana benthamiana to the virus. PMID:24581046

  16. Nitrogen isotope tracers of high-temperature fluid-rock interactions: Case study of the Catalina Schist, California

    NASA Astrophysics Data System (ADS)

    Bebout, Gray E.

    1997-09-01

    Nitrogen isotope data for metasomatized rocks, veins, and pegmatites in the Catalina Schist subduction zone metamorphic complex allow futher characterization of complex, high-P/T metasomatic proceses and evaluation of the scales of isotopic equilibration and fluid transport during subduction-zone metamorphism. Throughout the Catalina Schist, N resides predominantly as NH 4+ in white mica, which occurs in nearly all bulk compositions (i.e., metasedimentary, metamafic and, to a lesser extent, metaultramafic mélange) at all grades. Within each metamorphic unit of the Catalina Schist (ranging in grade from lawsonite-albite to amphibolite facies), δ 15N values of mica in metasomatized metamafic and metaultramafic rocks are consistent with the metasomatic addition of N from nearby, devolatilizing metasedimentary rocks into the initially N-poor mafic and ultramafic rocks. Within each unit, uniformity of mica δ 15N in metasomatized rocks relative to the δ 15N of metasedimentary rocks in the same unit implies mixing of N from nearby, heterogeneous metasedimentary sources, perhaps producing fluids with unifrom δ 15N at up to the kilometer scale. However, the trend in δ 15N of metasedimentary sources, with increasing metamorphic grade is inconsistent with larger scale up-temperature transfer of fluid (in this case, N 2-bearing) in the Catalina Schist paleosubduction zone; such flow (at scales of up to tens of kilometers) has been inferred through previous oxygen isotope study. Nitrogen isotope compositions are instead believed to have been controlled at a more local scale than the O isotope systematics, due to the more rock-dominated fluid-rock mass balance for N. The δ 15N of muscovite in leucosomes and pegmatites in amphibolite-grade metasedimentary exposures matches that of muscovite in metasedimentary hosts, implying minimal N-isotope fractionation during migmatization processes and possible transfer of metasedimentary N-isotope signatures in silicate melts. These

  17. Redox Signal-mediated Enhancement of the Temperature Sensitivity of Transient Receptor Potential Melastatin 2 (TRPM2) Elevates Glucose-induced Insulin Secretion from Pancreatic Islets.

    PubMed

    Kashio, Makiko; Tominaga, Makoto

    2015-05-01

    Transient receptor potential melastatin 2 (TRPM2) is a thermosensitive Ca(2+)-permeable cation channel expressed by pancreatic β cells where channel function is constantly affected by body temperature. We focused on the physiological functions of redox signal-mediated TRPM2 activity at body temperature. H2O2, an important molecule in redox signaling, reduced the temperature threshold for TRPM2 activation in pancreatic β cells of WT mice but not in TRPM2KO cells. TRPM2-mediated [Ca(2+)]i increases were likely caused by Ca(2+) influx through the plasma membrane because the responses were abolished in the absence of extracellular Ca(2+). In addition, TRPM2 activation downstream from the redox signal plus glucose stimulation enhanced glucose-induced insulin secretion. H2O2 application at 37 °C induced [Ca(2+)]i increases not only in WT but also in TRPM2KO β cells. This was likely due to the effect of H2O2 on KATP channel activity. However, the N-acetylcysteine-sensitive fraction of insulin secretion by WT islets was increased by temperature elevation, and this temperature-dependent enhancement was diminished significantly in TRPM2KO islets. These data suggest that endogenous redox signals in pancreatic β cells elevate insulin secretion via TRPM2 sensitization and activity at body temperature. The results in this study could provide new therapeutic approaches for the regulation of diabetic conditions by focusing on the physiological function of TRPM2 and redox signals. PMID:25817999

  18. Redox Signal-mediated Enhancement of the Temperature Sensitivity of Transient Receptor Potential Melastatin 2 (TRPM2) Elevates Glucose-induced Insulin Secretion from Pancreatic Islets*

    PubMed Central

    Kashio, Makiko; Tominaga, Makoto

    2015-01-01

    Transient receptor potential melastatin 2 (TRPM2) is a thermosensitive Ca2+-permeable cation channel expressed by pancreatic β cells where channel function is constantly affected by body temperature. We focused on the physiological functions of redox signal-mediated TRPM2 activity at body temperature. H2O2, an important molecule in redox signaling, reduced the temperature threshold for TRPM2 activation in pancreatic β cells of WT mice but not in TRPM2KO cells. TRPM2-mediated [Ca2+]i increases were likely caused by Ca2+ influx through the plasma membrane because the responses were abolished in the absence of extracellular Ca2+. In addition, TRPM2 activation downstream from the redox signal plus glucose stimulation enhanced glucose-induced insulin secretion. H2O2 application at 37 °C induced [Ca2+]i increases not only in WT but also in TRPM2KO β cells. This was likely due to the effect of H2O2 on KATP channel activity. However, the N-acetylcysteine-sensitive fraction of insulin secretion by WT islets was increased by temperature elevation, and this temperature-dependent enhancement was diminished significantly in TRPM2KO islets. These data suggest that endogenous redox signals in pancreatic β cells elevate insulin secretion via TRPM2 sensitization and activity at body temperature. The results in this study could provide new therapeutic approaches for the regulation of diabetic conditions by focusing on the physiological function of TRPM2 and redox signals. PMID:25817999

  19. Effect of operating temperature on transient behaviour of a biofilter treating waste-air containing n-butanol vapour during intermittent loading.

    PubMed

    Feizi, Farzaneh; Nasernejad, Bahram; Zamir, Seyed Morteza

    2016-05-01

    Transient-state removal of n-butanol vapour was investigated in a biofilter (BF) packed with compost and lava rock at different operating temperatures in the range of 30-45°C under intermittent loading (8 h per day). Adsorption on the inactive bed and biodegradation in the microbial-active bed were studied separately at an empty bed residence time (EBRT) of 1 min and inlet concentrations of 2.6-3.2 g m(-3), respectively. According to the transient experiments, the highest removal efficiency (RE) around 86% was obtained at 40°C due to a high microbial activity. Comparison of CO2 production and pure adsorption of n-butanol showed that adsorption was the major mechanism in the start-up of BF at each operating condition; although the impact of adsorption declined as temperature increased from 30°C to 45°C. The process was reaction limited at all operating conditions. Based on the determination of stoichiometric coefficients of n-butanol biodegradation, the CO2 production level was significantly lower than that of the chemical oxidation process which resulted in a decrease in environmental pollution. PMID:26507257

  20. Technical Note: How accurate can stalagmite formation temperatures be determined using vapour bubble radius measurements in fluid inclusions?

    NASA Astrophysics Data System (ADS)

    Spadin, F.; Marti, D.; Hidalgo-Staub, R.; Rička, J.; Fleitmann, D.; Frenz, M.

    2015-06-01

    Stalagmites are natural archives containing detailed information on continental climate variability of the past. Microthermometric measurements of fluid inclusion homogenisation temperatures allow determination of stalagmite formation temperatures by measuring the radius of stable laser-induced vapour bubbles inside the inclusions. A reliable method for precisely measuring the radius of vapour bubbles is presented. The method is applied to stalagmite samples for which the formation temperature is known. An assessment of the bubble radius measurement accuracy and how this error influences the uncertainty in determining the formation temperature is provided. We demonstrate that the nominal homogenisation temperature of a single inclusion can be determined with an accuracy of ±0.25 °C, if the volume of the inclusion is larger than 105 μm3. With this method, we could measure in a proof-of-principle investigation that the formation temperature of 10-20 yr old inclusions in a stalagmite taken from the Milandre cave is 9.87 ± 0.80 °C, while the mean annual surface temperature, that in the case of the Milandre cave correlates well with the cave temperature, was 9.6 ± 0.15 °C, calculated from actual measurements at that time, showing a very good agreement. Formation temperatures of inclusions formed during the last 450 yr are found in a temperature range between 8.4 and 9.6 °C, which corresponds to the calculated average surface temperature. Paleotemperatures can thus be determined within ±1.0 °C.

  1. Transient simulation of a helical-coil sodium/water steam generator

    SciTech Connect

    Van Tuyle, G.J.; Iwashita, T.

    1982-01-01

    The MINET (Momentum Integral Network) code heat exchanger model was used to analyze transient test data provided by PNC of Japan. Testing of the MINET model is part of a larger effort to facilitate and validate the use of the SSC/MINET code for MONJU plant transient analysis. In MINET, a heat exchanger is modeled using one or more representative tubes, with each tube consisting of the fluid inside the tube, the tube wall, and the fluid outside that is associated with the tube. The heat exchanger tube is divided into one or more axial nodes of equal length. Five time dependent equations are utilized per node, including the wall heat conduction equation and donor-cell differenced conservation of mass and energy equations for the fluids on both sides of the tube. These nodal equations are used to constrain the tube wall temperature, fluid mass flow rates, and fluid enthalpies.

  2. Temperature dependence of the transient photoconductive response in stretched trans-polyacetylene films with below-gap excitation

    NASA Technical Reports Server (NTRS)

    Walser, A. D.; Dorsinville, R.; Alfano, R. R.; Tubino, R.

    1991-01-01

    The temperature dependence of the picosecond photocurrent with below-gap excitation (1.06 microns) has been measured for a highly oriented form of transpolyacetylene. The one-dimensional picosecond photocurrent is independent of temperature. The three-dimensional picosecond photocurrent is temperature dependent with an activation energy of 63 meV. These results demonstrate the photoproduction of nonlinear charged carriers (solitons and polarons) at energies that are below the principal interband absorption edge.

  3. Effects of solder temperature on pin through-hole during wave soldering: thermal-fluid structure interaction analysis.

    PubMed

    Aziz, M S Abdul; Abdullah, M Z; Khor, C Y

    2014-01-01

    An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin through-hole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183(°)C) < T < 643.15 K (370(°)C). Both solvers were coupled by the real time coupling software and mesh-based parallel code coupling interface during analysis. In addition, an experiment was conducted to measure the temperature difference (ΔT) between the top and the bottom of the pin. Analysis results showed that an increase in temperature increased the structural displacement and the von Mises stress. Filling time exhibited a quadratic relationship to the increment of temperature. The deformation of pin showed a linear correlation to the temperature. The ΔT obtained from the simulation and the experimental method were validated. This study elucidates and clearly illustrates wave soldering for engineers in the PCB assembly industry. PMID:25225638

  4. Effects of Solder Temperature on Pin Through-Hole during Wave Soldering: Thermal-Fluid Structure Interaction Analysis

    PubMed Central

    Abdul Aziz, M. S.; Abdullah, M. Z.; Khor, C. Y.

    2014-01-01

    An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin through-hole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183°C) < T < 643.15 K (370°C). Both solvers were coupled by the real time coupling software and mesh-based parallel code coupling interface during analysis. In addition, an experiment was conducted to measure the temperature difference (ΔT) between the top and the bottom of the pin. Analysis results showed that an increase in temperature increased the structural displacement and the von Mises stress. Filling time exhibited a quadratic relationship to the increment of temperature. The deformation of pin showed a linear correlation to the temperature. The ΔT obtained from the simulation and the experimental method were validated. This study elucidates and clearly illustrates wave soldering for engineers in the PCB assembly industry. PMID:25225638

  5. Fluid channeling system

    NASA Technical Reports Server (NTRS)

    Davis, Donald Y. (Inventor); Hitch, Bradley D. (Inventor)

    1994-01-01

    A fluid channeling system includes a fluid ejector, a heat exchanger, and a fluid pump disposed in series flow communication The ejector includes a primary inlet for receiving a primary fluid, and a secondary inlet for receiving a secondary fluid which is mixed with the primary fluid and discharged therefrom as ejector discharge. Heat is removed from the ejector discharge in the heat exchanger, and the heat exchanger discharge is compressed in the fluid pump and channeled to the ejector secondary inlet as the secondary fluid In an exemplary embodiment, the temperature of the primary fluid is greater than the maximum operating temperature of a fluid motor powering the fluid pump using a portion of the ejector discharge, with the secondary fluid being mixed with the primary fluid so that the ejector discharge temperature is equal to about the maximum operating temperature of the fluid motor.

  6. Temperature dependence of viscosity in normal fluid 3He below 800 mK determined by a microelectromechanical oscillator

    NASA Astrophysics Data System (ADS)

    González, M.; Jiang, W. G.; Zheng, P.; Barquist, C. S.; Chan, H. B.; Lee, Y.

    2016-07-01

    A microelectromechanical system vibrating in its shear mode was used to study the viscosity of normal liquid temperature. Using a slide film damping model, the viscosity of the fluid was obtained. Our viscosity values are compared with previous measurements and with calculated values from Fermi-liquid theory. The crossover from the classical to the Fermi-liquid regime is manifest in the temperature dependence of viscosity. In the Fermi-liquid regime, the temperature dependence of viscosity changes from T-1 to T-2 on cooling, indicating a transition from the Stokes flow to the Couette flow regime.

  7. ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Effect of Carried-Envelope Phase on Transient Process in a Cascade-Type System

    NASA Astrophysics Data System (ADS)

    Zheng, Li-Li; Yu, Ling-Yan

    2010-03-01

    This paper investigates the effect of carried-envelope phase on transient process in a cascade-type atomic system, which is driven by two ultrashort laser pulses (probe and signal laser). It is found that the one- and two-photon processes corresponding to pathway |0> → |1> and |0> → |1> → |2> can be enhanced or suppressed by modulating the carried-envelope phases of probe laser pulse. Our numerical results also show that the transient populations of two excited states can be periodically affected by the carried-envelope phase of probe laser pulse. With certain time, the partial population transfer between two exited states can be realized just by adjusting the carried-envelope phase of probe laser pulse.

  8. Abundance of volatile and organic species in intermediate temperature fluids from the Von Damm and Piccard deep sea hydrothermal fields, Mid-Cayman Rise

    NASA Astrophysics Data System (ADS)

    McDermott, J. M.; Seewald, J.; Reeves, E. P.; German, C. R.; Sylva, S. P.; Klein, F.

    2012-12-01

    Two recently discovered submarine hydrothermal systems at the ultra-slow spreading Mid-Cayman Rise provide a unique opportunity to investigate how mixing and cooling influence hydrothermal fluid chemistry at the deepest-yet discovered, basalt-hosted Piccard vent field (4960m) and at the Von Damm vent field (2300m), postulated to be ultramafic-hosted. Vent fluids were collected in January 2012 during R/V Atlantis cruise AT18-16 with gas-tight samplers deployed by the ROV Jason II, allowing the characterization and quantification of redox-reactive volatile species and organic compounds. Von Damm vent fluids ranged in temperature from 21 to 226°C, whereas Piccard fluids ranged from 45 to 398°C. A key feature of these systems is the variety of fluids that were actively venting from the seafloor at 100 to 200°C, substantially cooler than the hottest fluids observed at either site. The lower temperatures reflect subsurface seawater mixing and/or conductive heat loss. Fluids venting within this temperature range have rarely been sampled at other systems, and the Cayman fluids thus present an excellent opportunity to study the effect of cooling and mixing processes on enriched volatile species such as H2, H2S, CO2 and CH4. Three dominant processes are thought to affect volatile and organic species in intermediate temperature fluids. These include microbial consumption or production, thermal alteration of biomass, and abiotic reactions. The effect of these processes on fluid compositions carries implications for carbon utilization and metabolic activity of modern microbial populations hosted within hydrothermal mineral deposits and ascending plumes, carbon cycling within hydrothermal systems, and net geochemical fluxes to the ocean. Endmember CO2 concentrations at Von Damm range from slightly enriched relative to seawater in the highest temperature fluids, to measurably depleted in the cooler fluids. Such CO2 depletions have not been previously observed in other acidic

  9. Measurement of the critical current and transient characteristics of a high-temperature superconductor tube using a pulsed current supply.

    SciTech Connect

    Cha, Y. S.

    1998-08-27

    The transient response of a melt-cast-processed BSCCO-2212 superconductor tube is investigated by using a pulsed current source. It was found that (1) the maximum induced current and the excitation current at field penetration increase with the maximum excitation current, and (2) there is a time delay between peak excitation current and peak magnetic field inside the superconductor. These observations can be explained by the concept of magnetic diffusion. The ac steady-state critical current of the superconductor was found to depend on the magnitude of the current increment. The critical current determined by using the pulsed current system agrees fairly well with the ac steady-state critical current determined by using relatively large current increment.

  10. Spring Fluids from a Low-temperature Hydrothermal System at Dorado Outcrop: The First Samples of a Massive Global Flux

    NASA Astrophysics Data System (ADS)

    Wheat, C. G.; Fisher, A. T.; McManus, J.; Hulme, S.; Orcutt, B.

    2015-12-01

    Hydrothermal circulation through the volcanic ocean crust extracts about one fourth of Earth's lithospheric heat. Most of this advective heat loss occurs through ridge flanks, areas far from the magmatic influence of seafloor spreading, at relatively low temperatures (2-25 degrees Celsius). This process results in a flux of seawater through the oceanic crust that is commensurate with that delivered to the ocean from rivers. Given this large flow, even a modest (1-5 percent) change in concentration during circulation would impact geochemical cycles for many ions. Until recently such fluids that embody this process have not been collected or quantified despite the importance of this process, mainly because no site of focused, low-temperature discharge has been found. In 2013 we used Sentry (an AUV) and Jason II (an ROV) to generate a bathymetric map and locate springs within a geologic context on Dorado Outcrop, a ridge flank hydrothermal system that typifies such hydrothermal processes in the Pacific. Dorado Outcrop is located on 23 M.y. old seafloor of the Cocos Plate, where 70-90 percent of the lithospheric heat is removed. Spring fluids collected in 2013 confirmed small chemical anomalies relative to seawater, requiring new methods to collect, analyze, and interpret samples and data. In 2014 the submersible Alvin utilized these methods to recover the first high-quality spring samples from this system and year-long experiments. These unique data and samples represent the first of their type. For example, the presence of dissolved oxygen is the first evidence of an oxic ridge flank hydrothermal fluid, even though such fluids have been postulated to exist throughout a vast portion of the oceanic crust. Furthermore, chemical data confirm modest anomalies relative to seawater for some elements. Such anomalies, if characteristic throughout the global ocean, impact global geochemical cycles, crustal evolution, and subsurface microbial activity.

  11. An assessment of the accuracy of isochore location techniques for H 2O-CO 2-NaCl fluids at granulite facies pressure-temperature conditions

    NASA Astrophysics Data System (ADS)

    Johnson, Eric Lee

    1992-01-01

    Synthetic H 2O-CO 2-NaCl fluid inclusions with XCO2 compositions ranging from 0.10-0.51 and relative salinities ( r-s = wtNaCl/( wt NaCl + wt H 2O )) of 6 to 23.9 wt% have been produced in spontaneously nucleated forsterite, diopside, and orthopyroxene hosts. Molar volumes of the fluids at the pressure and temperature of formation have been calculated using microthermometric data from the fluid inclusions. These P- V- T data are used to compare the accuracy of published methods of isochore location for H 2O-CO 2-NaCl fluids at elevated pressures and temperatures. The results of these analyses show that isochores calculated with the MRK equation of BOWERS and HELGESON ( Geochim. Cosmochim. Acta, vol. 47, 1247-1275, 1983) reproduce the trapping pressures and temperatures well for fluids with XCO2 ≤ 0.3 and up to 23.9 wt% NaCl. For a fluid with XCO2 = 0.49 and relative salinity of 15%, however, the agreement is poor. For these fluid compositions, the observed molar volume is larger than that predicted from the MRK equation of Bowers and Helgeson and, if not corrected, will give isochores that are too low in pressure for a given temperature. The ideal geometric mixing model of BROWN and LAMB ( Geochim. Cosmochim. Acta, vol. 53, 1209-1221, 1989) provides less satisfactory results for the fluid compositions studied.

  12. 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

  13. 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

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

    NASA Astrophysics Data System (ADS)

    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

  15. Development of advanced low-temperature heat transfer fluids for district heating and cooling, final report

    SciTech Connect

    Cho, Y.I.; Lorsch, H.G.

    1991-03-31

    The feasibility of adding phase change materials (PCMS) and surfactants to the heat transfer fluids in district cooling systems was investigated. It increases the thermal capacity of the heat transfer fluid and therefore decreases the volume that needs to be pumped. It also increases the heat transfer rate, resulting in smaller heat exchangers. The thermal behavior of two potential PCMS, hexadecane and tetradecane paraffin wax, was experimentally evaluated. The heat of fusion of these materials is approximately 60% of that of ice. They exhibit no supercooling and are stable under repeated thermal cycling. While test results for laboratory grade materials showed good agreement with data in the literature, both melting point and heat of fusion for commercial grade hexadecane were found to be considerably lower than literature values. PCM/water mixtures were tested in a laboratory-scale test loop to determine heat transfer and flow resistance properties. For 10% and 25% PCM/water slurries, the heat transfer enhancement was found to be approximately 18 and 30 percent above the value for water, respectively. Within the turbulent region, there is only a minor pumping penalty from the addition of up to 25% PCM to the water. Research is continuing on these fluids in order to determine their behavior in large-size loops and to arrive at optimum formulations.

  16. Flow Rates Measurement and Uncertainty Analysis in Multiple-Zone Water-Injection Wells from Fluid Temperature Profiles

    PubMed Central

    Reges, José E. O.; Salazar, A. O.; Maitelli, Carla W. S. P.; Carvalho, Lucas G.; Britto, Ursula J. B.

    2016-01-01

    This work is a contribution to the development of flow sensors in the oil and gas industry. It presents a methodology to measure the flow rates into multiple-zone water-injection wells from fluid temperature profiles and estimate the measurement uncertainty. First, a method to iteratively calculate the zonal flow rates using the Ramey (exponential) model was described. Next, this model was linearized to perform an uncertainty analysis. Then, a computer program to calculate the injected flow rates from experimental temperature profiles was developed. In the experimental part, a fluid temperature profile from a dual-zone water-injection well located in the Northeast Brazilian region was collected. Thus, calculated and measured flow rates were compared. The results proved that linearization error is negligible for practical purposes and the relative uncertainty increases as the flow rate decreases. The calculated values from both the Ramey and linear models were very close to the measured flow rates, presenting a difference of only 4.58 m³/d and 2.38 m³/d, respectively. Finally, the measurement uncertainties from the Ramey and linear models were equal to 1.22% and 1.40% (for injection zone 1); 10.47% and 9.88% (for injection zone 2). Therefore, the methodology was successfully validated and all objectives of this work were achieved. PMID:27420068

  17. Flow Rates Measurement and Uncertainty Analysis in Multiple-Zone Water-Injection Wells from Fluid Temperature Profiles.

    PubMed

    Reges, José E O; Salazar, A O; Maitelli, Carla W S P; Carvalho, Lucas G; Britto, Ursula J B

    2016-01-01

    This work is a contribution to the development of flow sensors in the oil and gas industry. It presents a methodology to measure the flow rates into multiple-zone water-injection wells from fluid temperature profiles and estimate the measurement uncertainty. First, a method to iteratively calculate the zonal flow rates using the Ramey (exponential) model was described. Next, this model was linearized to perform an uncertainty analysis. Then, a computer program to calculate the injected flow rates from experimental temperature profiles was developed. In the experimental part, a fluid temperature profile from a dual-zone water-injection well located in the Northeast Brazilian region was collected. Thus, calculated and measured flow rates were compared. The results proved that linearization error is negligible for practical purposes and the relative uncertainty increases as the flow rate decreases. The calculated values from both the Ramey and linear models were very close to the measured flow rates, presenting a difference of only 4.58 m³/d and 2.38 m³/d, respectively. Finally, the measurement uncertainties from the Ramey and linear models were equal to 1.22% and 1.40% (for injection zone 1); 10.47% and 9.88% (for injection zone 2). Therefore, the methodology was successfully validated and all objectives of this work were achieved. PMID:27420068

  18. The Hydrothermal Diamond Anvil Cell (HDAC) for raman spectroscopic studies of geologic fluids at high pressures and temperatures

    USGS Publications Warehouse

    Schmidt, Christian; Chou, I-Ming

    2012-01-01

    In this chapter, we describe the hydrothermal diamond-anvil cell (HDAC), which is specifically designed for experiments on systems with aqueous fluids to temperatures up to ⬚~1000ºC and pressures up to a few GPa to tens of GPa. This cell permits optical observation of the sample and the in situ determination of properties by ‘photon-in photon-out’ techniques such as Raman spectroscopy. Several methods for pressure measurement are discussed in detail including the Raman spectroscopic pressure sensors a-quartz, berlinite, zircon, cubic boron nitride (c-BN), and 13C-diamond, the fluorescence sensors ruby (α-Al2O3:Cr3+), Sm:YAG (Y3Al5O12:Sm3+) and SrB4O7:Sm2+, and measurements of phase-transition temperatures. Furthermore, we give an overview of published Raman spectroscopic studies of geological fluids to high pressures and temperatures, in which diamond anvil cells were applied.

  19. Chapter 7: The hydrothermal diamond anvil cell (HDAC) for Raman spectroscopic studies of geological fluids at high pressures and temperatures

    USGS Publications Warehouse

    Schmidt, Christian; Chou, I-Ming

    2012-01-01

    In this chapter, we describe the hydrothermal diamond-anvil cell (HDAC), which is specifically designed for experiments on systems with aqueous fluids to temperatures up to ~1000ºC and pressures up to a few GPa to tens of GPa. This cell permits optical observation of the sample and the in situ determination of properties by ‘photon-in photon-out’ techniques such as Raman spectroscopy. Several methods for pressure measurement are discussed in detail including the Raman spectroscopic pressure sensors a-quartz, berlinite, zircon, cubic boron nitride (c-BN), and 13C-diamond, the fluorescence sensors ruby (α-Al2O3:Cr3+), Sm:YAG (Y3Al5O12:Sm3+) and SrB4O7:Sm2+, and measurements of phase-transition temperatures. Furthermore, we give an overview of published Raman spectroscopic studies of geological fluids to high pressures and temperatures, in which diamond anvil cells were applied.

  20. Vibrational frequency shifts of fluid nitrogen fundamental and hot band transitions as a function of pressure and temperature

    SciTech Connect

    Schmidt, S.C.; Schiferl, D.; Zinn, A.S.; Ragan, D.D.; Moore, D.S.

    1989-01-01

    Coherent anti-Stokes Raman scattering (CARS) and spontaneous Raman spectroscopy have been used to obtain vibrational spectra of shock-compressed and static high-pressure fluid nitrogen, respectively. Vibrational frequencies were obtained from the CARS data using a semiclassical model for these spectra. Spontaneous Raman vibrational frequencies were determined by fitting data using a Lorentz shape line. A functional form was found for the dependence of the vibrational frequency on pressure and temperature to 40 GPa and 5000 K, respectively. The result is compared to a recent theoretical model. 6 refs., 2 figs., 1 tab.

  1. Effect of Metal Alloys, Degradation Inhibitors, Temperatures, and Exposure Duration on the Stability of Poly(hexafluoropropene oxide) Fluid

    NASA Technical Reports Server (NTRS)

    Paciorek, Kazimiera J. L.; Masuda, Steven R.; Lin, Wen-Huey; Jones, William R., Jr.

    1997-01-01

    Results of the action of 440C steel, Ti(4Al,4Mn), and Ti(6Al,4V) alloys on poly(hexafluoropropene oxide) fluid and the degradation inhibition by phosphate esters, phosphine, and monophospha-s-triazine are reported. The effects of temperature, exposure duration, and metal surface area are discussed. The studies show clearly the autocatalytic nature of the metal-promoted degradation, which explains the effectiveness of the degradation-arresting additives, even in the case of the highly detrimental titanium alloys.

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

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1981-01-01

    Thermionic energy converters and metallic-fluid heat pipes are well suited to serve together synergistically. The two operating cycles appear as simple and isolated as their material problems seem forebodingly deceptive and complicated. Simplified equations verify material properties and interactions as primary influences on the operational effectiveness of both. Each experiences flow limitations in thermal emission and vaporization because of temperature restrictions redounding from thermophysicochemical stability considerations. Topics discussed include: (1) successful limitation of alkali-metal corrosion; (2) protection against external hot corrosive gases; (3) coping with external and internal vaporization; (4) controlling interfacial reactions and diffusion; and (5) meeting other thermophysical challenges; expansion matches and creep.

  3. Winter stream temperature in the rain-on-snow zone of the Pacific Northwest: influences of hillslope runoff and transient snow cover

    NASA Astrophysics Data System (ADS)

    Leach, J. A.; Moore, R. D.

    2014-02-01

    Stream temperature dynamics during winter are less well studied than summer thermal regimes, but the winter season thermal regime can be critical for fish growth and development in coastal catchments. The winter thermal regimes of Pacific Northwest headwater streams, which provide vital winter habitat for salmonids and their food sources, may be particularly sensitive to changes in climate because they can remain ice-free throughout the year and are often located in rain-on-snow zones. This study examined winter stream temperature patterns and controls in small headwater catchments within the rain-on-snow zone at the Malcolm Knapp Research Forest, near Vancouver, British Columbia, Canada. Two hypotheses were addressed by this study: (1) winter stream temperatures are primarily controlled by advective fluxes associated with runoff processes and (2) stream temperatures should be depressed during rain-on-snow events, compared to rain-on-bare-ground events, due to the cooling effect of rain passing through the snowpack prior to infiltrating the soil or being delivered to the stream as saturation-excess overland flow. A reach-scale energy budget analysis of two winter seasons revealed that the advective energy input associated with hillslope runoff overwhelms vertical energy exchanges (net radiation, sensible and latent heat fluxes, bed heat conduction, and stream friction) and hyporheic energy fluxes during rain and rain-on-snow events. Historical stream temperature data and modelled snowpack dynamics were used to explore the influence of transient snow cover on stream temperature over 13 winters. When snow was not present, daily stream temperature during winter rain events tended to increase with increasing air temperature. However, when snow was present, stream temperature was capped at about 5 °C, regardless of air temperature. The stream energy budget modelling and historical analysis support both of our hypotheses. A key implication is that climatic warming may

  4. Retention of infectious haematopoietic necrosis virus infectivity in fish tissue homogenates and fluids stored at three temperatures.

    USGS Publications Warehouse

    Burke, J.; Mulcahy, D.

    1983-01-01

    Pools of brain, kidney, spleen, liver and gut tissues from several rainbow trout, Salmo gairdneri Richardson, and whole sockeye salmon, Oncorhynchus nerka (Walbaum), fry were homogenized with a known amount of infectious haematopoietic necrosis virus (IHNV). Virus was also added to ovarian fluids and sera pooled from several rainbow trout. The plaque assay was used to determine the retention of IHNV infectivity after different storage periods at 20°C, 4°C and —20°C. The work was used to evaluate homogenization as a remote field treatment of IHNV samples before shipment to the laboratory. Maintenance of viral infectivity varied widely among different homogenates and fluids. For short-term storage, 4°C was generally the most efficient temperature for preserving infectious virus in ovarian fluids, Sera and homogenates of eggs, spleen, whole fry and brain, while infectivity was most efficiently preserved in kidney and liver homogenates by storage at −20°C. Infectious virus was not detected in any sample stored for one year at −20°C. Variations in retention of viral infectivity make homogenization of samples in the field followed by transfer to the laboratory unacceptable.

  5. Study of the translational diffusion of the benzophenone ketyl radical in comparison with stable molecules in room temperature ionic liquids by transient grating spectroscopy

    SciTech Connect

    Nishiyama, Y.; Fukuda, M.; Terazima, M.; Kimura, Y.

    2008-04-28

    Transient grating (TG) spectroscopy has been applied to the photoinduced hydrogen-abstraction reaction of benzophenone (BP) in various kinds of room temperature ionic liquids (RTILs). After the photoexcitation of BP in RTILs, the formation of a benzophenone ketyl radical (BPK) was confirmed by the transient absorption method, and the TG signal was analyzed to determine the diffusion coefficients of BPK and BP. For comparison, diffusion coefficients of carbon monoxide (CO), diphenylacetylene (DPA), and diphenylcyclopropenone (DPCP) in various RTILs were determined by the TG method using the photodissociation reaction of DPCP. While the diffusion coefficients of the stable molecules BP, DPA, and DPCP were always larger than those predicted by the Stokes-Einstein (SE) relation in RTILs, that of BPK was much smaller than those of the stable molecules and relatively close to that predicted by the SE relation in all solvents. For the smallest molecule CO, the deviation from the SE relation was evident. The diffusion coefficients of stable molecules are better represented by a power law of the inverse of the viscosity when the exponent was less than unity. The ratios of the diffusion coefficient of BP to that of BPK were larger in RTILs (2.7-4.0) than those (1.4-2.3) in conventional organic solvents. The slow diffusion of BPK in RTILs was discussed in terms of the fluctuation of the local electric field produced by the surrounding solvent ions.

  6. Ultrafast transient absorption spectrum of the room temperature Ionic liquid 1-hexyl-3-methylimidazolium bromide: Confounding effects of photo-degradation

    NASA Astrophysics Data System (ADS)

    Musat, Raluca M.; Crowell, Robert A.; Polyanskiy, Dmitriy E.; Thomas, Marie F.; Wishart, James F.; Katsumura, Yosuke; Takahashi, Kenji

    2015-12-01

    The photochemistry of the charge transfer (CT) band of the room temperature ionic liquid (RTIL) 1-hexyl-3-methylimidazolium bromide (HMIm+/Br-) is investigated using near-IR to vis ultrafast transient absorption (TA) and steady-state UV absorption spectroscopies. Continuous irradiation of the CT band at 266 nm results in the formation of photo-products that absorb strongly at 266 nm. It is shown that these photo-products, which are apparently very stable, adversely affect ultrafast TA measurements. Elimination of these effects reveals at least two transient species that exist within the TA detection window of 100 fs to 3 ns and 500-1250 nm. One of the components is a short-lived (<1 ps) species that absorbs at 1080 nm. The second band exhibits a multicomponent spectrum that is very broad with an absorption maximum around 600 nm and a lifetime that is longer than the 3 ns window of our TA spectrometer. Within the signal to noise ratio of the TA spectrometer little to no solvated electron is generated by the CT mechanism.

  7. The combined effects of inlet fluid flow and temperature nonuniformity in cross flow plate-fin compact heat exchanger using finite element method

    NASA Astrophysics Data System (ADS)

    Ranganayakulu, C.; Seetharamu, K. N.

    An analysis of a crossflow plate-fin heat exchanger accouning for the combined effects of inlet fluid flow nonuniformity and temperature nonuniformity on both hot and cold fluid sides is carried out using a Finite Element Model. A mathematical equation is developed to generate different types of fluid flow/temperature maldistribution models considering the possible deviations in inlet fluid flow. Using these fluid flow maldistribution models, the exchanger effectiveness and its deteriorations due to flow/temperature nonuniformity are calculated for entire range of design and operating conditions. It was found that the performance deteriorations are quite significant in some typical applications due to inlet fluid flow/temperature nonuniformity. Zusammenfassung Mit Hilfe der Finitelement-Methode wird der zusammenwirkende Einfluß ungleichförmiger Strömungs- und Temperaturverteilungen am Eintritt des kalten, wie des warmen Fluids eines kreuzstrombetriebenen, berippten Kompakt-Plattenwärmetauschers untersucht. Über eine mathematische Beziehung lassen sich verschiedene Arten ungleichmäßiger Strömungs bzw. Temperaturverteilungen in den Eintrittsquerschnitten generieren. Unter Verwendung dieser Fehlverteilungsmodelle wird deren Einfluß auf den Austauscher-Gütegrad im gesamten Auslegungs- und Betriebsbereich ermittelt. Es zeigte sich, daß diese Auswirkungen bei typischen Ungleichförmigkeiten der Strömungs- bzw. Temperaturfelder in den Eintrittsquerschnitten erheblich sein können.

  8. Dress Warm, Focus on the Fluids and Be Patient: Studying Ice Habitats and Constraints on Microbial Life at Low Temperatures

    NASA Astrophysics Data System (ADS)

    Eicken, H.; Junge, K.; Deming, J.

    2002-12-01

    Studies of low-temperature environments on Earth can help guide exploration of other planetary environments that are of interest in the search for potential traces of life (or absence thereof) elsewhere in the solar system. Ice environments and habitats on Earth range from terrestrial permafrost to the polar ice caps or floating sea and lake ice. Despite the complexity of these different environments, the physical chemistry of unfrozen water - generally deemed a prerequisite for active life - and the pore microstructure can help in describing and categorizing different types of ice from an astrobiological perspective. In northern Alaska, we have studied constraints on microbial life in two types of ice, sea and lake ice, that bracket the range of availability of liquid water and solid surfaces. The latter have been found to be important for bacterial activity at very low temperatures, with active bacterial cells in sea ice documented down to temperatures of -20 C. Standard and epi-fluorescence microscopy adapted to studies at very low in-situ temperatures can help in locating individual cells and yield insight into the distribution of liquids, organisms and potential biomarkers in icy habitats. As the distribution of fluids, organisms and impurities is governed by segregation processes on different spatial scales, such work can aid in the planning of exploration campaigns (e.g., on Mars and Europa) and help guide the identification of intensive-study sites or the design of sampling equipment. Apart from such specific lessons, three major conclusions emerge: (1) The use of improved or new methods continues to push the envelope for activity of microbial life to lower temperatures, boding well for planetary exploration campaigns. (2) While the thermodynamics of water activity in ice may constitute an ultimate boundary, the low-temperature kinetic constraints currently present a significant challenge for the study of low-temperature life processes. This may call for

  9. Development of advanced low-temperature heat transfer fluids for district heating and cooling

    SciTech Connect

    Not Available

    1991-09-30

    The feasibility of adding phase change materials (PCMs) and surfactants to the heat transfer fluids in district cooling systems was investigated. It increases the thermal capacity of the heat transfer fluid and therefore decreases the volume that needs to be pumped. It also increases the heat transfer rate, resulting in smaller heat exchangers. The thermal behavior of two potential PCMs, hexadecane and tetradecane paraffin wax, was experimentally evaluated. The heat of fusion of these materials is approximately 60% of that of ice. They exhibit no supercooling and are stable under repeated thermal cycling. While test results for laboratory grade materials showed good agreement with data in the literature, both melting point and heat of fusion for commercial grade hexadecane were found to be considerably lower than literaturevalues. PCM/water mixtures were tested in a laboratory-scale test loop to determine heat transfer and flow resistance properties. When using PCMs in district cooling systems, clogging of frozen PCM particles isone of the major problems to be overcome. In the present project it is proposed to minimize or prevent clogging by the addition of an emulsifier. Effects of the emulsifier on the mixture of water and hexadecane(a PCM) were studied. As the amount of the emulsifier was increased, the size of the solid PCM particles became smaller. When the size of the particles was small enough, they did not stick together or stick to the cold surface of a heat exchanger. The amount of emulsifier to produce this condition was determined.

  10. PRISMATIC CORE COUPLED TRANSIENT BENCHMARK

    SciTech Connect

    J. Ortensi; M.A. Pope; G. Strydom; R.S. Sen; M.D. DeHart; H.D. Gougar; C. Ellis; A. Baxter; V. Seker; T.J. Downar; K. Vierow; K. Ivanov

    2011-06-01

    The Prismatic Modular Reactor (PMR) is one of the High Temperature Reactor (HTR) design concepts that have existed for some time. Several prismatic units have operated in the world (DRAGON, Fort St. Vrain, Peach Bottom) and one unit is still in operation (HTTR). The deterministic neutronics and thermal-fluids transient analysis tools and methods currently available for the design and analysis of PMRs have lagged behind the state of the art compared to LWR reactor technologies. This has motivated the development of more accurate and efficient tools for the design and safety evaluations of the PMR. In addition to the work invested in new methods, it is essential to develop appropriate benchmarks to verify and validate the new methods in computer codes. The purpose of this benchmark is to establish a well-defined problem, based on a common given set of data, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events. The benchmark-working group is currently seeking OECD/NEA sponsorship. This benchmark is being pursued and is heavily based on the success of the PBMR-400 exercise.

  11. Frequency and temperature dependence of complex strontium titanate electrorheological fluids under an alternating electric field

    NASA Astrophysics Data System (ADS)

    Ma, Yong; Zhang, Yuling; Lu, Kunquan

    1998-05-01

    The electrorheological (ER) behavior of suspensions of water-free complex strontium titanate particles, synthesized by means of a modified sol-gel technique, in silicone oil have been investigated under an ac electric field. The frequency and temperature dependence of the shear stress show that the shear stress decreases monotonically with frequency and reaches a maximum value when the temperature is around 70 °C. The ER behavior has been explained on the basis of dielectric measurements.

  12. Generalized Fluid System Simulation Program (GFSSP) Version 6 - General Purpose Thermo-Fluid Network Analysis Software

    NASA Technical Reports Server (NTRS)

    Majumdar, Alok; Leclair, Andre; Moore, Ric; Schallhorn, Paul

    2011-01-01

    GFSSP stands for Generalized Fluid System Simulation Program. It is a general-purpose computer program to compute pressure, temperature and flow distribution in a flow network. GFSSP calculates pressure, temperature, and concentrations at nodes and calculates flow rates through branches. It was primarily developed to analyze Internal Flow Analysis of a Turbopump Transient Flow Analysis of a Propulsion System. GFSSP development started in 1994 with an objective to provide a generalized and easy to use flow analysis tool for thermo-fluid systems.

  13. Temperature Dependent Capacitance-Voltage And Deep Level Transient Spectroscopy Study Of Self-Assembled Ge Quantum Dots Embedded In P-type Silicon

    SciTech Connect

    Rangel-Kuoppa, Victor-Tapio; Chen Gang; Jantsch, Wolfgang

    2011-12-23

    Temperature dependent Capacitance-Voltage (TCV) and Deep Level Transient Spectroscopy (DLTS) techniques were used to study how Ge Quantum Dots (QDs) embedded in Silicon trap charge. Atomic Force Microscopy (AFM) is used to obtain the density of QDs, which is in the order of 3x10{sup 11} cm{sup -2}. Three shallow levels, with activation energies of 40, 65 and 90 meV, and densities around 10{sup 16} cm{sup -3}, are found and are related to Boron. Four deep levels, with activation energies of 110, 150, 330 and 380 meV, and densities between 2x10{sup 15} cm{sup -3} and 5x10{sup 15} cm{sup -3}, are also found. TCV results suggest they are related to the Ge QDs.

  14. Determination of allowable fluid temperature during start-up operation of outlet header under the assumption of constant and temperature-dependent material properties

    NASA Astrophysics Data System (ADS)

    Rząsa, Dariusz; Duda, Piotr

    2013-09-01

    Modern supercritical power plants operate at very high temperatures and pressures. Thus the construction elements are subjected to both high thermal and mechanical loads. As a result high stresses in those components are created. In order to operate safely, it is important to monitor stresses, especially during start-up and shut-down processes. The maximum stresses in the construction elements should not exceed the allowable stresses that are defined according to boiler regulations. It is important to find optimum operating parameters, that can assure safe heating and cooling processes. The optimum parameters define temperature and pressure histories that can keep the highest stresses within allowable limit and reduce operation time as much as possible. In this paper a new numerical method for determining optimum working fluid parameters is presented. In this method, properties of steel can be assumed as constant or temperature dependent. The constant value is taken usually at the average temperature of the operation cycle. For both cases optimal parameters are determined. Based on these parameters start-up operations for both cases are conducted. During entire processes stresses in the heated element are monitored. The results obtained are compared with German boiler regulations - Technische Regeln fur Dampfkessel 301.

  15. Intra-hole fluid convection: High-resolution temperature time monitoring

    NASA Astrophysics Data System (ADS)

    Cermak, Vladimir; Safanda, Jan; Kresl, Milan

    2008-01-01

    SummaryIntra-hole convection was monitored in detail by a string of five high resolution temperature probes arranged in an 8-m long unit lowered step-by-step into a slim experimental borehole. The experiment was performed in the test hole Sporilov (Prague). A 50-m long depth interval (between 80 and 130 m) was covered in five successive steps. The hole itself is 150 m deep and 112 mm in diameter. The experiment occurred in the internal plastic tube 5 cm in diameter which is sealed from the influx of ground water in the surrounding strata. In the studied interval the temperature gradient varies in the range of 0.020-0.0215 K/m. The borehole was drilled in 1993 and has been in equilibrium since then. Temperature as a function of time was sampled in 15 s intervals and the individual measuring steps took from 1.5 to 2.5 days, each temperature time series thus contained 9000 up to 16,000 data points. The obtained results revealed: (1) temperature-time series present a complex apparently random oscillation pattern with the amplitude of up to 0.045 K; (2) the statistical analysis confirmed a quasi-periodic skeleton of a two-frequency oscillation structure. Shorter periods of 10 up to 30 min are superposed on longer variations with period of several hours. (3) The quasi-periodicity may be hidden under a considerable amount of noise. (4) Within the studied interval the quasi-periodic convection may alternate with a relatively "quiet" regime when temperature oscillations decreased to only 0.004-0.01 K range. (5) Regardless of certain deterministic rules present in the dynamics, the bulk of temperature variations are chaotic.

  16. High work output combined with high ambient temperatures caused heat exhaustion in a wildland firefighter despite high fluid intake.

    PubMed

    Cuddy, John S; Ruby, Brent C

    2011-06-01

    The purpose of this case study is to examine the physiological/behavioral factors leading up to heat exhaustion in a male wildland firefighter during wildland fire suppression. The participant (24 years old, 173 cm, 70 kg, and 3 years firefighting experience) experienced heat exhaustion following 7 hours of high ambient temperatures and arduous work on the fire line during the month of August. At the time of the heat-related incident (HRI), core temperature was 40.1 °C (104.2 °F) and skin temperature was 34.4 °C (93.9 °F). His work output averaged 1067 counts·min(-1) (arbitrary units for measuring activity) for the 7 hours prior to the HRI, a very high rate of work over an extended time period during wildfire suppression. In the 2.5 hours leading up to the heat incident, he was exposed to a mean ambient temperature of 44.6 °C (112.3 °F), with a maximum temperature of 59.7 °C (139.5 °F). He consumed an average of 840 mL·h(-1) in the 7 hours leading up to the incident and took an average of 24 ± 11 drinks·h(-1) (total of 170 drinks). The combined effects of a high work rate and high ambient temperatures resulted in an elevated core temperature and a higher volume and frequency of drinking than typically seen in this population, ultimately ending in heat exhaustion and removal from the fire line. The data demonstrate that heat-related incidents can occur even with aggressive fluid intake during wildland fire suppression. PMID:21664560

  17. Planetary fluids He and NH/sub 3/ at high shock pressures and temperatures

    SciTech Connect

    Nellis, W.J.; Radousky, H.B.; Mitchell, A.C.; Holmes, N.C.; Ross, M.; Young, D.A.

    1985-04-01

    Liquid He at 4.3 K and 1 atm was shocked to 16 GPa (160 kbar) and 12,000 K and double-shocked to 56 GPa and 21,000 K. Liquid perturbation theory was used to determine an effective interatomic potential from which the equation of state of He can be obtained over a wide range of densities and temperatures in the envelopes of the outer planets. A new fast optical pyrometer and a cryogenic specimen holder for liquid NH/sub 3/ were developed to measure shock temperatures of 4400 and 3600 K at pressures of 59 and 48 GPa. These conditions correspond to those in the ice layers in Uranus and Neptune. The shock temperature data are in reasonable agreement with an equation of state by Ree based on an intermolecular potential derived from NH/sub 3/ Hugoniot data.

  18. The boundary element analysis of steady-state and transient temperature fields of turbine rotors and discs

    NASA Astrophysics Data System (ADS)

    Huang, Shu H.; Ma, Zhi Y.

    The paper presents a formulation of the boundary element method for axisymmetric heat transfer. The main advantage of this technique compared with conventional methods is that it reduces the dimensionality of the problem, resulting in a smaller system of equations to be solved. The method is also well suited for solving problems where high gradients occur. The formulation is used to compute the temperature fields of a gas turbine disk and of a steam turbine rotor.

  19. A quantitative model for flux flow resistivity and Nernst effect of vortex fluid in high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Li, Rong; She, Zhen-Su; Yin, Lan; State Key Laboratory for Turbulence; Complex Systems Team

    Transport properties of vortex fluid in high-temperature superconductors have been described in terms of viscous dynamics of magnetic and thermal vortices. We have constructed a quantitative model by extending the Bardeen-Stephen model of damping viscosity to include the contributions of flux pinning in low temperature and vortex-vortex interaction in high magnetic field. A uniformly accurate description of flux flow resistivity and Nernst signal is achieved for empirical data over a wide range of temperature and magnetic field strength. A discrepancy of three orders of magnitude between data and Anderson model of Nernst signal is pointed out, suggesting the existence of anomalous transport in high-temperature superconductor beyond mere quantum and thermal fluctuations. The model enables to derive a set of physical parameters characterizing the vortex dynamics from the Nernst signal, as we illustrate with an analysis of six samples of Bi2Sr2-yLayCuO6 and Bi2Sr2CaCu2O8+δ.

  20. The simulation of temperature distribution and relative humidity with liquid concentration of 50% using computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Yohana, Eflita; Yulianto, Mohamad Endy; Kwang-Hwang, Choi; Putro, Bondantio; Yohanes Aditya W., A.

    2015-12-01

    The study of humidity distribution simulation inside a room has been widely conducted by using computational fluid dynamics (CFD). Here, the simulation was done by employing inputs in the experiment of air humidity reduction in a sample house. Liquid dessicant CaCl2was used in this study to absorb humidity in the air, so that the enormity of humidity reduction occured during the experiment could be obtained.The experiment was conducted in the morning at 8 with liquid desiccant concentration of 50%, nozzle dimension of 0.2 mms attached in dehumidifier, and the debit of air which entered the sample house was 2.35 m3/min. Both in inlet and outlet sides of the room, a DHT 11 censor was installed and used to note changes in humidity and temperature during the experiment. In normal condition without turning on the dehumidifier, the censor noted that the average temperature inside the room was 28°C and RH of 65%.The experiment result showed that the relative humidity inside a sample house was decreasing up to 52% in inlet position. Further, through the results obtained from CFD simulation, the temperature distribution and relative humidity inside the sample house could be seen. It showed that the concentration of liquid desiccant of 50% experienced a decrease while the relative humidity distribution was considerably good since the average RH was 55% followed by the increase in air temperature of 29.2° C inside the sample house.

  1. Constraints on fluids and mass transfer during high-temperature during high-temperature contact metamorphism: Marble Canyon, west Texas

    SciTech Connect

    Anovitz, L.M.; Kalin, R.M.; Ruiz, J. . Dept. of Geosciences)

    1992-01-01

    Contact metamorphism of the Hueco and Bone Springs Limestones, Marble Canyon, west Texas formed sanidinite facies assemblages near the contact. Mw + Mel + Rn + Sp lies between: 2Mo + Rn = Ak + Mw and Mw + Rn = Ak + 2[alpha]C[sub 2]S, on Sp + Ak = 3Mw + Rn + CO[sub 2], and below Sp + Rn = [alpha]C[sub 2]S + CO[sub 2]. Assuming P = 370 bars and correcting for solid solutions yields contact temperatures of 700--800 C, and 0.001 < XCO[sub 2] < 0.02. Further from the contact carbonate-bearing assemblages reappear. Several distal samples contain Di + Dol. This assemblage lies below Di + 3Dol = 2Of + 4Cc + 2CO[sub 2], above Dol + 2Qz = Di + 2CO[sub 2], and at XCO[sub 2] concentrations above Tr + 3Cc = 4Di + Dol + CO[sub 2] + H[sub 2]O. These reactions imply 400 C < T < 500 C and XCO[sub 2] > 0.95. Thus there appear to have been large lateral gradients in XCO[sub 2] during metamorphism. Stable isotopic results verify the apparent differences between the two formations. Trace element data are currently only available from the Hueco Fm. REE patterns are light element enriched, and show intermediate to strong Eu and distinct Ce anomalies. La/Yb ratios fall into two groups 14--65 for some samples near the contact, and 8--16 for bulk rock samples at greater distances. U concentrations are high in the skarn, low in the marble near the contact and increase with distance. Ta, W, Pb, Cs and Ba concentrations also increase with distance, although the Ta, W, and Pb depletion is concentrated within 20 cm of the contact. Transects for all of these elements, however, contains significant internal structure.

  2. Transient performance

    NASA Astrophysics Data System (ADS)

    Curnock, Barry

    Gas turbine engine transient behavior, that which is concerned with the changes in engine parameters during acceleration or decceleration of an engine from one steady state point to a different steady state point, is considered. An engine can also experience cyclic aerodynamic phenomena which occur at a nominally steady condition; examples are compressor rotator stall and intake or afterburner buzz. The following are discussed: certification requirements; mechanism of acceleration; compressor working lines and surge; and some important factors (pressure level, moment of inertia, heat soakage, clearances, measurement of transients, thrust reversal, and transient maneuvers which involve significant changes to the shaft speeds of the engine). A set of graphics illustrating transient performance is presented.

  3. Transient Shifts of Incubation Temperature Reveal Immediate and Long-Term Transcriptional Response in Chicken Breast Muscle Underpinning Resilience and Phenotypic Plasticity.

    PubMed

    Naraballobh, Watcharapong; Trakooljul, Nares; Murani, Eduard; Brunner, Ronald; Krischek, Carsten; Janisch, Sabine; Wicke, Michael; Ponsuksili, Siriluck; Wimmers, Klaus

    2016-01-01

    transiently decreased incubation temperature, which did not affect the phenotypes, prompts compensatory effects reflecting resilience. In contrast, higher incubation temperature triggers gene expression and has long-term effects on the phenotype. These mechanisms of considerable phenotypic plasticity contribute to the biodiversity and broaden the basis for managing poultry populations. PMID:27611643

  4. Experimentally-determined carbon isotope fractionation in and between methane-bearing melt and fluid to upper mantle temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Mysen, Bjorn

    2016-07-01

    The behavior of melts and fluids is at the core of understanding formation and evolution of the Earth. To advance our understanding of their role, high-pressure/-temperature experiments were employed to determine melt and fluid structure together with carbon isotope partitioning within and between (CH4 +H2O +H2)-saturated aluminosilicate melts and (CH4 +H2O +H2)-fluids. The samples were characterized with vibrational spectroscopy while at temperatures and pressures from 475° to 850 °C and 92 to 1158 MPa, respectively. The solution equilibrium is 2CH4 +Qn = 2 CH3- +H2O +Q n + 1 where the superscript, n, in the Qn-notation describes silicate species where n denotes the number of bridging oxygen. The solution equilibrium affects the carbon isotope fractionation factor between melt and fluid, αmelt/fluid. Moreover, it is significantly temperature-dependent. The αmelt/fluid < 1 with temperatures less than about 1050 °C, and is greater than 1 at higher temperature. Methane-bearing melts can exist in the upper mantle at fO2 ≤fO2 (MW) (Mysen et al., 2011). Reduced (Csbnd H)-species in present-day upper mantle magma, therefore, are likely. During melting and crystallization in this environment, the δ13C of melts increases with temperature at a rate of ∼ 0.6 ‰ /°C. From the simple-system data presented here, at T ≤ 1050°C, melt in equilibrium with a peridotite-(CH4 +H2O +H2)-bearing mantle source will be isotopically lighter than fluid. At higher temperatures, melts will be isotopically heavier. Degassing at T ≤ 1050°C will shift δ13C of degassed magma to more positive values, whereas degassing at T ≥ 1050°C, will reduce the δ13C of the degassed magma.

  5. CORRELATION OF THE GLASS TRANSITION TEMPERATURE OF PLASTICIZED PVC USING A LATTICE FLUID MODEL

    EPA Science Inventory

    A model has been developed to describe the composition dependence of the glass transition temperature (Tg) of polyvinyl chloride (PVC) + plasticizer mixtures. The model is based on Sanchez-Lacombe equation of state and the Gibbs-Di Marzio criterion, which states that th...

  6. Low Temperature Sorbents for removal of Sulfur Compounds from fluid feed Streams

    SciTech Connect

    Siriwardane, Ranjan

    1999-09-30

    A sorbent material is provided comprising a material reactive with sulfur, a binder unreactive with sulfur and an inert material, wherein the sorbent absorbs the sulfur at temperatures between 30 and 200 C. Sulfur absorption capacity as high as 22 weight percent has been observed with these materials.

  7. Low Temperature Sorbents for Removal of Sulfur Compounds from Fluid Feed Streams

    DOEpatents

    Siriwardane, Ranjani

    2004-06-01

    A sorbent material is provided comprising a material reactive with sulfur, a binder unreactive with sulfur and an inert material, wherein the sorbent absorbs the sulfur at temperatures between 30 and 200 C. Sulfur absorption capacity as high as 22 weight percent has been observed with these materials.

  8. Heat can cool near-critical fluids.

    PubMed

    Beysens, Daniel; Fröhlich, Thomas; Garrabos, Yves

    2011-11-01

    We report experiments with very compressible fluids near the liquid-gas critical point. These experiments are performed (i) under microgravity in low Earth orbit by using SF(6) at liquidlike density and (ii) under Earth's gravity with CO(2) at gaslike density. The sample fluid is filled in an interferometer cell with its walls maintained at constant temperature. In situ thermistors measure the local fluid temperature. One of the thermistors is also used as a heat source to generate heat pulses. With no gravity-induced fluid convection, the evolution of fluid temperature is governed by the balance of heat flux between the thermal boundary layer of the heat source, which compresses the bulk fluid, and the thermal boundary layer at the wall, which expands it. When heat pulses are applied to the fluid under weak or Earth's gravity, a long thermal transient is observed at the end of the heat pulse where the bulk fluid temperature reaches significantly below the initial temperature. This unconventional cooling originates from the fast decompression of the fluid, which is induced by the rapid convectively disappearing hot boundary layer at the heat source, and the persistence of an anomalously thin cold boundary layer convectively induced at the cell wall. This striking phenomenon is observed in a large range of temperature, density, and various thermodynamic conditions. This anomalous cooling effect persists for an appreciable period of time corresponding to the diffusive destruction of the cold boundary layer. We found that the effect is also more pronounced when the free fall acceleration is large. We have analyzed the result by using a simple one-dimensional model with ad hoc convective heat losses. PMID:22181401

  9. Torque Transient of Magnetically Drive Flow for Viscosity Measurement

    NASA Technical Reports Server (NTRS)

    Ban, Heng; Li, Chao; Su, Ching-Hua; Lin, Bochuan; Scripa, Rosalia N.; Lehoczky, Sandor L.

    2004-01-01

    Viscosity is a good indicator of structural changes for complex liquids, such as semiconductor melts with chain or ring structures. This paper discusses the theoretical and experimental results of the transient torque technique for non-intrusive viscosity measurement. Such a technique is essential for the high temperature viscosity measurement of high pressure and toxic semiconductor melts. In this paper, our previous work on oscillating cup technique was expanded to the transient process of a magnetically driven melt flow in a damped oscillation system. Based on the analytical solution for the fluid flow and cup oscillation, a semi-empirical model was established to extract the fluid viscosity. The analytical and experimental results indicated that such a technique has the advantage of short measurement time and straight forward data analysis procedures

  10. Solvation of [alpha]-hydroxydiphenylmethyl radical in room temperature ionic liquids studied by transient FT-EPR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kawai, Akio; Hidemori, Takehiro; Shibuya, Kazuhiko

    2005-10-01

    To understand solvation in room temperature ionic liquids (RTILs), an FT-EPR spectrum of α-hydroxydiphenylmethyl (HDPM) radical was measured in several RTILs of tert-alkylammonium or alkylimidazolium salts with anions of PF6-, BF4-, (CF 3SO 2) 2N -, CF3SO3-,WO42-, Cl - and Br -. The hyperfine coupling constant of the hydroxyl proton depends on Gutmann's donor number of the anions, while the constants of phenyl α-protons are essentially the same for these RTILs. This result suggests the electron donor character of anions is important in HDPM solvation in RTILs through the anion-OH group hydrogen-bond.

  11. Electron temperature in transient plasmas from quasi-steady ratio of isoelectronic lines: application to picosecond and subpicosecond plasmas

    NASA Astrophysics Data System (ADS)

    Marjoribanks, R. S.; Budnik, F. W.; Chen, H.; Meyerhofer, D. D.

    1996-02-01

    We have extended the technique of plasma temperature measurement by ratio of isoelectronic lines, recently developed with nanosecond laser plasmas, to the diagnosis of picosecond and subpicosecond plasmas. We have found a major benefit-particularly for short-pulse laser plasmas-that even where level populations are far from steady-state values, the ratio of isoelectronic lines may be nearly steady state, which considerably simplifies interpretation. We describe theoretical and experimental investigations for plasmas created from solid targets by 100-fs-10-ps high-intensity laser pulses and report the experimental application of the technique to lambda =1.05 - mu m laser pulses at 1016 W cm -2 .

  12. The effects of temperature, pH and redox state on the stability of glutamic acid in hydrothermal fluids

    NASA Astrophysics Data System (ADS)

    Lee, Namhey; Foustoukos, Dionysis I.; Sverjensky, Dimitri A.; Cody, George D.; Hazen, Robert M.

    2014-06-01

    Natural hydrothermal vent environments cover a wide range of physicochemical conditions involving temperature, pH and redox state. The stability of simple biomolecules such as amino acids in such environments is of interest in various fields of study from the origin of life to the metabolism of microbes at the present day. Numerous previous experimental studies have suggested that amino acids are unstable under hydrothermal conditions and decompose rapidly. However, previous studies have not effectively controlled the redox state of the hydrothermal fluids. Here we studied the stability of glutamate with and without reducing hydrothermal conditions imposed by 13 mM aqueous H2 at temperatures of 150, 200 and 250 °C and initial (25 °C) pH values of 6 and 10 in a flow-through hydrothermal reactor with reaction times from 3 to 36 min. We combined the experimental measurements with theoretical calculations to model the in situ aqueous speciation and pH values. As previously observed under hydrothermal conditions, the main reaction involves glutamate cyclizing to pyroglutamate through a simple dehydration reaction. However, the amounts of decomposition products of the glutamate detected, including succinate, formate, carbon dioxide and ammonia depend on the temperature, the pH and particularly the redox state of the fluid. In the absence of dissolved H2, glutamate decomposes in the sequence glutamate, glutaconate, α-hydroxyglutarate, ketoglutarate, formate and succinate, and ultimately to CO2 and micromolar quantities of H2(aq). Model speciation calculations indicate the CO2, formate and H2(aq) are not in metastable thermodynamic equilibrium. However, with 13 mM H2(aq) concentrations, the amounts of decomposition products are suppressed at all temperatures and pH values investigated. The small amounts of CO2 and formate present are calculated to be in metastable equilibrium with the H2. It is further proposed that there is a metastable equilibrium between glutamate

  13. Development of a high temperature pH electrode for geothermal fluids. Final report, Task 1

    SciTech Connect

    Niedrach, L.W.; Stoddard, W.H.

    1981-04-01

    There has been no serious application of pH measurements above 150/sup 0/C stemming from the fact that there have been no practical probes available that are capable of operation under the required conditions of temperature and pressure. Recently, a new approach to such measurements was developed in which an oxygen ion conducting ceramic membrane (e.g., stabilized zirconia) is being employed in a sensor somewhat analogous to the glass electrode. The new sensor retains the specificity of the glass electrode, is equally insensitive to interference from redox active species, and possesses markedly superior resistance to attack by aqueous media at high temperatures. The status of the new sense at the inception of the contract is summarized and plans for the first year's investigation are outlined.

  14. Measurement of soot concentration and bulk fluid temperature and velocity using modulated laser-induced incandescence

    NASA Astrophysics Data System (ADS)

    Snelling, David R.; Sawchuk, Robert A.; Smallwood, Gregory J.; Thomson, Kevin

    2015-04-01

    The use of a modulated LII two-colour technique to measure soot temperature in a laminar diffusion flame is described, and the results compared to CARS experiments. A sinusoidal modulated diode laser is used to excite the soot, and both the modulated LII intensity and its relative phase to the excitation source are measured with a lock-in amplifier and recorded. Modulation frequencies from 25 to 200,000 Hz were employed. The temperature is derived from the ratio of the modulated LII radiation signal at 445 and 750 nm, and the results compared to values obtained by CARS spectroscopy. The modulated LII temperatures were largely independent of modulation frequency and agreed well with the CARS temperatures. A theory is developed to explain the dependence of the phase delay of the modulated LII signal (with reference to that of the laser excitation source) on gas replacement time in the sample volume, soot cooling rate and soot volume fraction. The theory is shown to give a reasonable fit to the experimental results at all frequencies. At lower frequencies, the phase delay is dominated by the gas replacement time in the sample volume and at higher frequencies by the cooling rate of the heated soot. Time constants for both processes and the soot volume fraction are derived from the data and shown to be largely in agreement with the expected values. Using modulated LII-determined soot volume fraction and inverted and scatter corrected line-of-sight attenuation-determined absorption coefficients, the soot refractive index absorption function E(m) was measured to be between 0.45 and 0.42 over the wavelength range of 436-825 nm.

  15. Transient studies of capillary-induced flow

    NASA Technical Reports Server (NTRS)

    Reagan, M. K.; Bowman, W. J.

    1993-01-01

    This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

  16. An experimental investigation of transient fatigue crack growth phenomena under elevated temperature conditions in superalloy 718 and titanium Ti-1100. Ph.D. Thesis

    SciTech Connect

    Rosenberger, A.H.

    1993-01-01

    Two transient crack growth phenomena are investigated in high temperature structural alloys. The first phenomenon examined is the growth behavior of small cracks under elastic-plastic conditions in Alloy 718 at 650 C. The second phenomenon to be investigated is the mechanism of the creep-fatigue crack growth in a new near-alpha titanium alloy, Ti-1100. Understanding these phenomena is essential for accurate fracture mechanics based residual life component management techniques. The first part of the dissertation is an experimental study of the elastic-plastic fatigue behavior of small surface cracks in Alloy 718 at 650 C conducted under conditions of total strain control. During cycling, the crack growth was continuously monitored using a direct current potential drop technique while the influence of crack closure was monitored using a laser interferometry technique measuring the crack mouth opening displacement. The crack tip plastic zone size was also measured using a post-test delta phase decoration technique. Results show that the growth rates of the small cracks correlate well with long crack data when using an appropriate elastic-plastic driving force parameter. The anomalous crack growth rates observed in some experiments were found to be experimental transients dominated by the crack initiation fracture and do not represent an intrinsic behavior of Alloy 718. The second part of this document deals with a series of crack growth experiments performed on the near-alpha titanium alloy, Ti-1100, to determine the mechanism of the creep-fatigue interaction. Based on pure creep crack growth results, the increase in the creep-fatigue crack growth rate is not amenable to separate contributions of creep crack growth and fatigue crack growth. A mechanism has been proposed to account for the increase in creep-fatigue crack growth rate based on the planar slip of titanium alloys which results in the formation of dislocation pileups at the prior beta grain boundaries.

  17. Influence of working fluid evaporation temperature in the near-critical point region on the effectiveness of ORC power plant operation

    NASA Astrophysics Data System (ADS)

    Nowak, Władysław; Borsukiewicz-Gozdur, Aleksandra; Wiśniewski, Sławomir

    2012-09-01

    In the paper presented are definitions of specific indicators of power which characterize the operation of the organic Rankine cycle (ORC) plant. These quantities have been presented as function of evaporation temperature for selected working fluids of ORC installation. In the paper presented also is the procedure for selection of working fluid with the view of obtaining maximum power. In the procedure of selection of working fluid the mentioned above indicators are of primary importance. In order to obtain maximum power there ought to be selected such working fluids which evaporate close to critical conditions. The value of this indicator increases when evaporation enthalpy decreases and it is known that the latent heat of evaporation decreases with temperature and reaches a value of zero at the critical point.

  18. Ion temperature profiles in front of a negative planar electrode studied by a one-dimensional two-fluid model

    NASA Astrophysics Data System (ADS)

    Gyergyek, T.; Kovačič, J.

    2016-06-01

    Plasma-wall transition is studied by a one-dimensional steady state two-fluid model. Continuity and momentum exchange equations are used for the electrons, while the continuity, momentum exchange, and energy transport equation are used for the ions. Electrons are assumed to be isothermal. The closure of ion equations is made by the assumption that the heat flux is zero. The model equations are solved for potential, ion and electron density, and velocity and ion temperature as independent variables. The model includes coulomb collisions between ions and electrons and charge exchange collisions between ions and neutral atoms of the same species and same mass. The neutral atoms are assumed to be essentially at rest. The model is solved for finite ratio ɛ = /λ D L between the Debye length and λD and ionization length L in the pre-sheath and in the sheath at the same time. Charge exchange collisions heat the ions in the sheath and the pre-sheath. Even a small increase of the frequency of charge exchange collisions causes a substantial increase of ion temperature. Coulomb collisions have negligible effect on ion temperature in the pre-sheath, while in the sheath they cause a small cooling of ions. The increase of ɛ causes the increase of ion temperature. From the ion density and temperature profiles, the polytropic function κ is calculated according to its definition given by Kuhn et al. [Phys. Plasmas 13, 013503 (2006)]. The obtained profiles of κ indicate that the ion flow is isothermal only in a relatively narrow region in the pre-sheath, while close to the sheath edge and in the sheath it is closer to adiabatic. The ion sound velocity is space dependent and exhibits a maximum. This maximum indicates the location of the sheath edge only in the limit ɛ → 0 .

  19. Acetosyringone, pH and temperature effects on transient genetic transformation of immature embryos of Brazilian wheat genotypes by Agrobacterium tumefaciens

    PubMed Central

    Manfroi, Ernandes; Yamazaki-Lau, Elene; Grando, Magali F.; Roesler, Eduardo A.

    2015-01-01

    Abstract Low transformation efficiency is one of the main limiting factors in the establishment of genetic transformation of wheat via Agrobacterium tumefaciens. To determine more favorable conditions for T-DNA delivery and explant regeneration after infection, this study investigated combinations of acetosyringone concentration and pH variation in the inoculation and co-cultivation media and co-culture temperatures using immature embryos from two Brazilian genotypes (BR 18 Terena and PF 020037). Based on transient expression of uidA, the most favorable conditions for T-DNA delivery were culture media with pH 5.0 and 5.4 combined with co-culture temperatures of 22 °C and 25 °C, and a 400 μM acetosyringone supplement. These conditions resulted in blue foci in 81% of the embryos. Media with more acidic pH also presented reduced A. tumefaciens overgrowth during co-culture, and improved regeneration frequency of the inoculated explants. BR 18 Terena was more susceptible to infection by A. tumefaciens than PF 020037. We found that it is possible to improve T-DNA delivery and explant regeneration by adjusting factors involved in the early stages of A. tumefaciens infection. This can contribute to establishing a stable transformation procedure in the future. PMID:26537604

  20. Corrosion mechanism of 13Cr stainless steel in completion fluid of high temperature and high concentration bromine salt

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Xu, Lining; Lu, Minxu; Meng, Yao; Zhu, Jinyang; Zhang, Lei

    2014-09-01

    A series of corrosion tests of 13Cr stainless steel were conducted in a simulated completion fluid environment of high temperature and high concentration bromine salt. Corrosion behavior of specimens and the component of corrosion products were investigated by means of scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). The results indicate that 13Cr steel suffers from severe local corrosion and there is always a passive halo around every pit. The formation mechanism of the passive halo is established. OH- ligand generates and adsorbs in a certain scale because of abundant OH- on the surface around the pits. Passive film forms around each pit, which leads to the occurrence of passivation in a certain region. Finally, the dissimilarities in properties and morphologies of regions, namely the pit and its corresponding passive halo, can result in different corrosion sensitivities and may promote the formation of macroscopic galvanic pairs

  1. [Therapeutic hypothermia after cardiac arrest. A cold intravenous fluid, a cooling helmet and a cooling blanket efficiently reduce body temperature].

    PubMed

    Friberg, Hans; Nielsen, Niklas; Karlsson, Torbjörn; Cronberg, Tobias; Widner, Håkan; Englund, Elisabet; Ersson, Anders

    2004-07-22

    Two controlled randomized trials have shown that mild systemic hypothermia after cardiac arrest is beneficial for neurological outcome and one of the studies shows an improved survival rate. A pilot study was performed to evaluate a model of induced hypothermia after cardiac arrest, using cold intravenous fluids and surface cooling with a cold helmet and a coldwater blanket (Thermowrap). The main purpose was to evaluate our cooling method regarding efficacy, safety and usability. Five unconscious patients after cardiac arrest were treated with induced hypothermia of whom three survived with good recovery to six-month follow up. Two patients died in the ICU without regaining consciousness. There were no adverse events during treatment. We conclude that our method is reasonably fast compared to other published methods, it is easy to perform and it offers a good temperature control during cooling and rewarming. Routines for evaluating prognosis and neurological outcome after cardiac arrest and hypothermia treatment need to be revised. PMID:15314936

  2. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    NASA Astrophysics Data System (ADS)

    Wang, Hsiu-Wen; Fanelli, Victor R.; Reiche, Helmut M.; Larson, Eric; Taylor, Mark A.; Xu, Hongwu; Zhu, Jinlong; Siewenie, Joan; Page, Katharine

    2014-12-01

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO2 measurements. The new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H2 and natural gas uptake/storage.

  3. Major and trace-element composition and pressure-temperature evolution of rock-buffered fluids in low-grade accretionary-wedge metasediments, Central Alps

    NASA Astrophysics Data System (ADS)

    Miron, George D.; Wagner, Thomas; Wälle, Markus; Heinrich, Christoph A.

    2013-05-01

    The chemical composition of fluid inclusions in quartz crystals from Alpine fissure veins was determined by combination of microthermometry, Raman spectroscopy, and LA-ICPMS analysis. The veins are hosted in carbonate-bearing, organic-rich, low-grade metamorphic metapelites of the Bündnerschiefer of the eastern Central Alps (Switzerland). This strongly deformed tectonic unit is interpreted as a partly subducted accretionary wedge, on the basis of widespread carpholite assemblages that were later overprinted by lower greenschist facies metamorphism. Veins and their host rocks from two locations were studied to compare several indicators for the conditions during metamorphism, including illite crystallinity, graphite thermometry, stability of mineral assemblages, chlorite thermometry, fluid inclusion solute thermometry, and fluid inclusion isochores. Fluid inclusions are aqueous two-phase with 3.7-4.0 wt% equivalent NaCl at Thusis and 1.6-1.7 wt% at Schiers. Reproducible concentrations of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, B, Al, Mn, Cu, Zn, Pb, As, Sb, Cl, Br, and S could be determined for 97 fluid inclusion assemblages. Fluid and mineral geothermometry consistently indicate temperatures of 320 ± 20 °C for the host rocks at Thusis and of 250 ± 30 °C at Schiers. Combining fluid inclusion isochores with independent geothermometers results in pressure estimates of 2.8-3.8 kbar for Thusis, and of 3.3-3.4 kbar for Schiers. Pressure-temperature estimates are confirmed by pseudosection modeling. Fluid compositions and petrological modeling consistently demonstrate that chemical fluid-rock equilibrium was attained during vein formation, indicating that the fluids originated locally by metamorphic dehydration during near-isothermal decompression in a rock-buffered system.

  4. Diagenesis associated with subaerial exposure of Miocene strata, southeastern Spain: Implications for sea-level change and preservation of low-temperature fluid inclusions in calcite cement

    USGS Publications Warehouse

    Goldstein, R.H.; Franseen, E.K.; Mills, M.S.

    1990-01-01

    Many ancient carbonate rocks contain calcite cements that precipitated from shallow, fresh groundwater that entered strata during events of subaerial exposure. Such low-temperature cementation may be difficult to interpret from fluid inclusion studies because some of the inclusions may reequilibrate during later thermal events. Miocene rocks of southeast Spain provide an example of the utility of fluid inclusion studies in rocks that have not been subjected to significant heating. In the Mesa Roldan area, one type of calcite cement occurs exclusively below a regional stratigraphic surface of enigmatic origin. The cement has petrographic characteristics indicative of cementation in the vadose zone (generally thought to be a zone of oxidation) but has cathodoluminescent bands containing reduced manganese and iron. Primary fluid inclusions contain mostly fresh water, have variable ratios of vapor to liquid, and are at one atmosphere of pressure. Our observations indicate that calcite precipitated from a freshwater vadose zone, which was subjected to local or repetitive saturation, and minor brackish water. The fluid inclusion data indicate that low-temperature fluid inclusions can be preserved in ancient sequences despite a later history of different pore fluids. This indication of subaerial diagenesis of distal slope deposits suggests a relative sea-level drop of at least 50-55 m during the Late Miocene. Similar petrographic and fluid inclusion observations can be used to interpret sea-level changes in other areas. ?? 1990.

  5. Subseafloor phase equilibria in high-temperature hydrothermal fluids of the Lucky Strike Seamount (Mid-Atlantic Ridge, 37°17‧N)

    NASA Astrophysics Data System (ADS)

    Pester, Nicholas J.; Reeves, Eoghan P.; Rough, Mikaella E.; Ding, Kang; Seewald, Jeffrey S.; Seyfried, William E.

    2012-08-01

    As part of an integrated study conducted at the Lucky Strike Seamount (Mid-Atlantic Ridge, 37°17'N) in 2008, gas-tight sampling devices were used to collect high-temperature (˜300 °C) hydrothermal fluids issuing from sulfide structures distributed throughout the vent field located in the summit depression. Compared with previous observations from 1993 to 1997, the most substantial changes in vent fluid compositions are dramatically increased CO2 concentrations (˜5×, up to 133 mmol/L) and the observation of vent fluids enriched in dissolved chloride relative to seawater. Combined with an increase in δ13C values by ˜4‰ in 2008, the elevated CO2 indicates replenishment of the magmatic heat source and may be indicative of a recent magmatic event. The additional supporting fluid chemistry is, however, similar to that of the previous sampling intervals, necessitating a reassessment of the subseafloor controls on vent fluid chemistry at Lucky Strike in the context of recently obtained geophysical data that provides the depth/extent of a steady-state magma chamber. Two-phase behavior is indicated by the chloride variability in the vent fluids; and comparison with experimental data for the associated chloride-dependent partitioning of minor/trace elements suggests the possibility of a similar source fluid for all the vent structures, while limiting the likelihood of shallow phase separation and subseafloor mixing for the hydrothermal end-members. A recently calibrated Fe/Mn geothermometer indicates minimum subseafloor equilibration temperatures of 350-385 °C. However, constraints imposed by dissolved Si/Cl in conjunction with geophysical observations are consistent with peak reaction conditions at temperatures of 430-475 °C and pressures near the top of the axial magma chamber (˜410-480 bars), where magmatic CO2 becomes entrained in the circulating fluids. The distance between the magma chamber and the seafloor at Lucky Strike is substantially greater than at

  6. Combined temperature and density series for fluid-phase properties. I. Square-well spheres

    SciTech Connect

    Elliott, J. Richard; Schultz, Andrew J.; Kofke, David A.

    2015-09-21

    Cluster integrals are evaluated for the coefficients of the combined temperature- and density-expansion of pressure: Z = 1 + B{sub 2}(β) η + B{sub 3}(β) η{sup 2} + B{sub 4}(β) η{sup 3} + ⋯, where Z is the compressibility factor, η is the packing fraction, and the B{sub i}(β) coefficients are expanded as a power series in reciprocal temperature, β, about β = 0. The methodology is demonstrated for square-well spheres with λ = [1.2-2.0], where λ is the well diameter relative to the hard core. For this model, the B{sub i} coefficients can be expressed in closed form as a function of β, and we develop appropriate expressions for i = 2-6; these expressions facilitate derivation of the coefficients of the β series. Expanding the B{sub i} coefficients in β provides a correspondence between the power series in density (typically called the virial series) and the power series in β (typically called thermodynamic perturbation theory, TPT). The coefficients of the β series result in expressions for the Helmholtz energy that can be compared to recent computations of TPT coefficients to fourth order in β. These comparisons show good agreement at first order in β, suggesting that the virial series converges for this term. Discrepancies for higher-order terms suggest that convergence of the density series depends on the order in β. With selection of an appropriate approximant, the treatment of Helmholtz energy that is second order in β appears to be stable and convergent at least to the critical density, but higher-order coefficients are needed to determine how far this behavior extends into the liquid.

  7. Combined temperature and density series for fluid-phase properties. I. Square-well spheres.

    PubMed

    Elliott, J Richard; Schultz, Andrew J; Kofke, David A

    2015-09-21

    Cluster integrals are evaluated for the coefficients of the combined temperature- and density-expansion of pressure: Z = 1 + B2(β) η + B3(β) η(2) + B4(β) η(3) + ⋯, where Z is the compressibility factor, η is the packing fraction, and the B(i)(β) coefficients are expanded as a power series in reciprocal temperature, β, about β = 0. The methodology is demonstrated for square-well spheres with λ = [1.2-2.0], where λ is the well diameter relative to the hard core. For this model, the B(i) coefficients can be expressed in closed form as a function of β, and we develop appropriate expressions for i = 2-6; these expressions facilitate derivation of the coefficients of the β series. Expanding the B(i) coefficients in β provides a correspondence between the power series in density (typically called the virial series) and the power series in β (typically called thermodynamic perturbation theory, TPT). The coefficients of the β series result in expressions for the Helmholtz energy that can be compared to recent computations of TPT coefficients to fourth order in β. These comparisons show good agreement at first order in β, suggesting that the virial series converges for this term. Discrepancies for higher-order terms suggest that convergence of the density series depends on the order in β. With selection of an appropriate approximant, the treatment of Helmholtz energy that is second order in β appears to be stable and convergent at least to the critical density, but higher-order coefficients are needed to determine how far this behavior extends into the liquid. PMID:26395690

  8. Combined temperature and density series for fluid-phase properties. I. Square-well spheres

    NASA Astrophysics Data System (ADS)

    Elliott, J. Richard; Schultz, Andrew J.; Kofke, David A.

    2015-09-01

    Cluster integrals are evaluated for the coefficients of the combined temperature- and density-expansion of pressure: Z = 1 + B2(β) η + B3(β) η2 + B4(β) η3 + ⋯, where Z is the compressibility factor, η is the packing fraction, and the Bi(β) coefficients are expanded as a power series in reciprocal temperature, β, about β = 0. The methodology is demonstrated for square-well spheres with λ = [1.2-2.0], where λ is the well diameter relative to the hard core. For this model, the Bi coefficients can be expressed in closed form as a function of β, and we develop appropriate expressions for i = 2-6; these expressions facilitate derivation of the coefficients of the β series. Expanding the Bi coefficients in β provides a correspondence between the power series in density (typically called the virial series) and the power series in β (typically called thermodynamic perturbation theory, TPT). The coefficients of the β series result in expressions for the Helmholtz energy that can be compared to recent computations of TPT coefficients to fourth order in β. These comparisons show good agreement at first order in β, suggesting that the virial series converges for this term. Discrepancies for higher-order terms suggest that convergence of the density series depends on the order in β. With selection of an appropriate approximant, the treatment of Helmholtz energy that is second order in β appears to be stable and convergent at least to the critical density, but higher-order coefficients are needed to determine how far this behavior extends into the liquid.

  9. Transient Fluid Flow Along Basement Faults and Rupture Mechanics: Can We Expect Injection-Induced Earthquake Behavior to Correspond Directly With Injection Operations?

    NASA Astrophysics Data System (ADS)

    Norbeck, J. H.; Horne, R. N.

    2015-12-01

    We explored injection-induced earthquake behavior in geologic settings where basement faults are connected hydraulically to overlying saline aquifers targeted for wastewater disposal. Understanding how the interaction between natural geology and injection well operations affects the behavior of injection-induced earthquake sequences has important implications for characterizing seismic hazard risk. Numerical experiments were performed to investigate the extent to which seismicity is influenced by the migration of pressure perturbations along fault zones. Two distinct behaviors were observed: a) earthquake ruptures that were confined to the pressurized region of the fault and b) sustained earthquake ruptures that propagated far beyond the pressure front. These two faulting mechanisms have important implications for assessing the manner in which seismicity can be expected respond to injection well operations.Based upon observations from the numerical experiments, we developed a criterion that can be used to classify the expected faulting behavior near wastewater disposal sites. The faulting criterion depends on the state of stress, the initial fluid pressure, the orientation of the fault, and the dynamic friction coefficient of the fault. If the initial ratio of shear to effective normal stress resolved on the fault (the prestress ratio) is less than the fault's dynamic friction coefficient, then earthquake ruptures will tend to be limited by the distance of the pressure front. In this case, parameters that affect seismic hazard assessment, like the maximum earthquake magnitude or earthquake recurrence interval, could correlate with injection well operational parameters. For example, the maximum earthquake magnitude might be expected to grow over time in a systematic manner as larger patches of the fault are exposed to significant pressure changes. In contrast, if the prestress ratio is greater than dynamic friction, a stress drop can occur outside of the pressurized

  10. Transient Analysis of a Magnetic Heat Pump

    NASA Technical Reports Server (NTRS)

    Schroeder, E. A.

    1985-01-01

    An experimental heat pump that uses a rare earth element as the refrigerant is modeled using NASTRAN. The refrigerant is a ferromagnetic metal whose temperature rises when a magnetic field is applied and falls when the magnetic field is removed. The heat pump is used as a refrigerator to remove heat from a reservoir and discharge it through a heat exchanger. In the NASTRAN model the components modeled are represented by one-dimensional ROD elements. Heat flow in the solids and fluid are analyzed. The problem is mildly nonlinear since the heat capacity of the refrigerant is temperature-dependent. One simulation run consists of a series of transient analyses, each representing one stroke of the heat pump. An auxiliary program was written that uses the results of one NASTRAN analysis to generate data for the next NASTRAN analysis.

  11. Robust regulation of temperature in reactor-regenerator fluid catalytic cracking units

    SciTech Connect

    Alvarez-Ramirez, J.; Aguilar, R.; Lopez-Isunza, F.

    1996-05-01

    FCC processes involve complex interactive dynamics which are difficult to operate and control as well as poorly known reaction kinetics. This work concerns the synthesis of temperature controllers for FCC units. The problem is addressed first for the case where perfect knowledge of the reaction kinetics is assumed, leading to an input-output linearizing state feedback. However, in most industrial FCC units, perfect knowledge of reaction kinetics and composition measurements is not available. To address the problem of robustness against uncertainties in the reaction kinetics, an adaptive model-based nonlinear controller with simplified reaction models is presented. The adaptive strategy makes use of estimates of uncertainties derived from calorimetric (energy) balances. The resulting controller is similar in form to standard input-output linearizing controllers and can be tuned analogously. Alternatively, the controller can be tuned using a single gain parameter and is computationally efficient. The performance of the closed-loop system and the controller design procedure are shown with simulations.

  12. Lateral ventricular cerebrospinal fluid diffusivity as a potential neuroimaging marker of brain temperature in multiple sclerosis: a hypothesis and implications.

    PubMed

    Hasan, Khader M; Lincoln, John A; Nelson, Flavia M; Wolinsky, Jerry S; Narayana, Ponnada A

    2015-04-01

    In this retrospective study we tested the hypothesis that the net effect of impaired electrical conduction and therefore increased heat dissipation in multiple sclerosis (MS) results in elevated lateral ventricular (LV) cerebrospinal fluid (CSF) diffusivity as a measure of brain temperature estimated in vivo using diffusion tensor imaging (DTI). We used validated DTI-based segmentation methods to obtain normalized LV-CSF volume and its corresponding CSF diffusivity in 108 MS patients and 103 healthy controls in the age range of 21-63 years. The LV CSF diffusivity was ~2% higher in MS compared to controls that correspond to a temperature rise of ~1°C that could not be explained by changes in the CSF viscosity due to altered CSF protein content in MS. The LV diffusivity decreased with age in healthy controls (r=-0.29; p=0.003), but not in MS (r=0.15; p=0.11), possibly related to MS pathology. Age-adjusted LV diffusivity increased with lesion load (r=0.518; p=1×10(-8)). Our data suggest that the total brain lesion load is the primary contributor to the increase in LV CSF diffusivity in MS. These findings suggest that LV diffusivity is a potential in vivo biomarker of the mismatch between heat generation and dissipation in MS. We also discuss limitations and possible confounders. PMID:25485790

  13. Bosonic lasing and trapping of a dressed photon fluid in InGaN at room temperature

    NASA Astrophysics Data System (ADS)

    Cobet, Munise

    2016-08-01

    The generation of a quantum fluid of dressed photons at room temperature is experimentally demonstrated in an InGaN microcavity which is divided into two- and one-dimensional sections, resulting in single- and switchable multilevel coherent light emission. Ultra-low-threshold operation is attributed to the slight but robust excitonic fraction of the photonic condensate representing a bosonic laser working below the Mott transition (polariton laser). In contrast to equilibrium Bose-Einstein condensates, the nonequilibrium driven-dissipative nature enables the population of higher orbitals if any confinement potential is present to induce enhanced quantum correlations. Trapping inside microwire spacers leads to a polariton harmonic oscillator resulting in discrete states in an equidistant ladder of photonic orbitals. Level occupation and selection of a specific wave function is managed via optical control, mimicking a quantum emitter on a macroscopic level. It shows that exotic states of matter can be realized in rather simple structures at room temperature directly visible to the human eye. It represents also an excellent opportunity to study basic many-body dynamics in one-dimensional bosonic matter by simultaneously settling an optimized fabrication technique for devices enabling practical Boolean quantum logic gates for optical computing.

  14. The role of boron and fluids in high temperature, shallow level metamorphism of the Chugach Metamorphic Complex, Alaska

    NASA Technical Reports Server (NTRS)

    Sisson, V. B.; Leeman, W. P.

    1988-01-01

    The possible role of boron (B) involvement in granite equilibria and generation of melts during crustal metamorphism has been a focus of speculation in recent literature. Most of the evidence for such involvement derives from experimental data which implies that the addition of B will lower the temperature of the granite solidus. Also the presence of tourmaline has a minor effect on the temperature of the solidus. Further indirect evidence that B may be involved in partial melting processes is the observation that granulites are commonly depleted in B, whereas the B content of low grade metapelites can be high (up to 2000 ppm). Researchers' measurements of the whole-rock B contents of granulites from the Madras region, India are low, ranging from 0.4 to 2.6 ppm. Ahmad and Wilson suggest that B was mobilized in the fluid phase during granulite facies metamorphism of the Broken Hill Complex, Australia. Thus, it appears that during the amphibolite to granulite transition, B is systematically lost from metasediments. The B that is released will probably partition into the vapor phase and/or melt phase. Preliminary measurements imply that the boron content of rocks in the Chugach Metamorphic Complex is not sufficient to influence the processes of partial melting at low pressures.

  15. Time-temperature evolution of microtextures and contained fluids in a plutonic alkali feldspar during heating

    NASA Astrophysics Data System (ADS)

    Parsons, Ian; Fitz Gerald, John D.; Lee, James K. W.; Ivanic, Tim; Golla-Schindler, Ute

    2010-08-01

    , advance from the original interfaces toward the mid-line of each twinned, semicoherent lamella. In places, the homogenisation interfaces have shapes reflecting the local arrangements of nanotunnels or pull-aparts. Analyses confirm that the change in alkali composition is also relatively sharp at these interfaces. Si-Al disordering is far slower than alkali homogenisation so that tweed texture in orthoclase, tartan twinning in irregular microcline, and Albite twins in albite lamellae and patches persisted in all our experiments, including 5,478 h at 700°C, 148 h at 1,000°C and 5 h at 1,100°C, even though the ensemble in each case was chemically homogeneous. Nanotunnels and pull-aparts were modified after only 50 min at 500°C following the simulated 40Ar/39Ar step-heating schedule. New features called ‘slots’ developed away from albite lamellae, often with planar traces linking slots to the closest lamella. Slot arrays were often aligned along ghost-like regions of diffraction contrast which may mark the original edges of lamellae. We suggest that the slot arrays result from healing of pull-aparts containing fluid. At 700°C and above, the dominant defects were subspherical ‘bubbles’, which evolved from slots or from regions of deuteric coarsening. The small degree of partial melting observed after 5 h at 1,100°C was often in the vicinity of bubbles. Larger micropores, which formed at subgrain boundaries in patch perthite during deuteric coarsening, retain their shape up to the melting point, as do the subgrain boundaries themselves. It is clear that modification of defects providing potential fast pathways for diffusion in granitic alkali feldspars begins below 500°C and that defect character progressively changes up to, and beyond, the onset of melting.

  16. Geochemistry of low-temperature springs northwest of Yellowstone caldera: Seeking the link between seismicity, deformation, and fluid flow

    USGS Publications Warehouse

    Evans, William C.; Bergfeld, D.; van Soest, M.C.; Huebner, M.A.; Fitzpatrick, J.; Revesz, K.M.

    2006-01-01

    A comprehensive geochemical survey of springs outside the northwest margin of the Yellowstone caldera was undertaken in 2003 and 2004. This survey was designed to detect: (1) active leakage from a huge reservoir of CO2 gas recently postulated to extend from beneath the caldera into this area; and (2) lingering evidence for subsurface flow of magmatic fluids into this area during the 1985 seismic swarm and concomitant caldera subsidence. Spring temperatures are low (< 15 ??C), but two large-discharge springs contain 14C-dead carbon that can be identified as magmatic from calculated end-member values for ??13C(dead) and 3He/C(dead) of - 4??? and 1 ?? 10- 10, respectively, similar to values for intra-caldera fumarolic and hot-spring gases. However, the combined discharge of magmatic C is only 5.4 tonnes/day, < 0.1% of the total output from Yellowstone. The two springs have slightly elevated 3He/4He ratios near 1 RA and anomalous concentrations of Cl, Li, and B, and appear to represent minor leakage of gas-depleted, thermal waters out of the caldera. The small CO2 signal detected in the springs is difficult to reconcile with a large underlying reservoir of gas in faulted and seismically active terrain. When considered with analyses from previous decades, the results provide no evidence to associate the ten-year period of caldera deflation that began in 1985 with expulsion of magmatic fluids through the caldera rim in this area.

  17. Three dimensional (temperature-tension-composition) phase map of mixed DOPC-DPPC vesicles: Two solid phases and a fluid phase coexist on three intersecting planes.

    PubMed

    Chen, Dong; Santore, Maria M

    2014-11-01

    Mapping the phase behavior of multicomponent phospholipid membranes has been an ongoing pursuit, motivated by interest in both fundamental physics and cell function. Prior investigations addressed temperature-composition space and the features of the associated domains. The current study additionally considers membrane tension, analogous to pressure in bulk materials. Focusing on model mixed 1,2-dioleoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DOPC and DPPC respectively) membranes, we examine the thermodynamic impact of tension on fluid-solid coexistence and the nature of phase-separated domains. Reported here is the 3 dimensional composition-temperature-tension phase map containing three intersecting curved surfaces. Depending on the system's position in this 3D space, giant unilamellar vesicles containing DOPC and DPPC may exhibit, in addition to a 2-component fluid Lα phase, two different types of solid DPPC-rich domains: tracer-excluding hexagonal patches or tracer-selective stripes. The fluid phase occurs at high temperatures. At cool temperatures striped solid DPPC-rich domains coexist with the fluid at elevated tensions. These stripes occur independent of tension, at the coolest temperatures. At low tensions and intermediate temperatures, patchy solid DPPC-rich domains coexist with the Lα fluid and may persist, if kinetically trapped, at lower temperatures. We associate the striped DPPC domains with a tilt-gel (Lβ') morphology and the hexagonal DPPC patches with a dense corrugated ripple phase (Pβ'). These assignments, based on the reported areal densities of the corrugated and tilt solids, enabled first principles estimates of the coexistence boundaries that match the experiments well, including the tension sensitivity of coexistence curves and triple-point-like features for fixed composition. PMID:25064155

  18. Fluid Shifts

    NASA Technical Reports Server (NTRS)

    Stenger, M.; Hargens, A.; Dulchavsky, S.; Ebert, D.; Lee, S.; Lauriie, S.; Garcia, K.; Sargsyan, A.; Martin, D.; Ribeiro, L.; Lui, J.; Macias, B.; Arbeille, P.; Danielson, R.; Chang, D.; Johnston, S.; Ploutz-Snyder, R.; Smith, S.

    2016-01-01

    NASA is focusing on long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low-Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but more than 50% of ISS astronauts experienced more profound, chronic changes with objective structural and functional findings such as papilledema and choroidal folds. Globe flattening, optic nerve sheath dilation, and optic nerve tortuosity also are apparent. This pattern is referred to as the visual impairment and intracranial pressure (VIIP) syndrome. VIIP signs and symptoms, as well as postflight lumbar puncture data, suggest that elevated intracranial pressure (ICP) may be associated with the spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight, and to correlate these findings with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as the VIIP-related effects of those shifts, is predicted by the crewmember's preflight conditions and responses to acute hemodynamic manipulations (such as head-down tilt). Lastly, we will evaluate the patterns of fluid distribution in ISS astronauts during acute reversal of fluid shifts through application of lower body negative pressure (LBNP) interventions to characterize and explain general and individual responses. METHODS: We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the Figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, calcaneus tissue thickness (by

  19. Analysis of ionization wave dynamics in low-temperature plasma jets from fluid modeling supported by experimental investigations

    NASA Astrophysics Data System (ADS)

    Yousfi, M.; Eichwald, O.; Merbahi, N.; Jomaa, N.

    2012-08-01

    This work is devoted to fluid modeling based on experimental investigations of a classical setup of a low-temperature plasma jet. The latter is generated at atmospheric pressure using a quartz tube of small diameter crossed by helium gas flow and surrounded by an electrode system powered by a mono-polar high-voltage pulse. The streamer-like behavior of the fast plasma bullets or ionization waves launched in ambient air for every high-voltage pulse, already emphasized in the literature from experimental or analytical considerations or recent preliminary fluid models, is confirmed by a numerical one-moment fluid model for the simulation of the ionization wave dynamics. The dominant interactions between electron and the main ions present in He-air mixtures with their associated basic data are taken into account. The gradual dilution of helium in air outside the tube along the axis is also considered using a gas hydrodynamics model based on the Navier-Stokes equation assuming a laminar flow. Due to the low magnitude of the reduced electric field E/N (not exceeding 15 Td), it is first shown that consideration of the stepwise ionization of helium metastables is required to reach the critical size of the electron avalanches in order to initiate the formation of ionization waves. It is also shown that a gas pre-ionization ahead of the wave front of about 109 cm-3 (coming from Penning ionization without considering the gas photo-ionization) is required for the propagation. Furthermore, the second ionization wave experimentally observed during the falling time of the voltage pulse, between the powered electrode and the tube exit, is correlated with the electric field increase inside the ionized channel in the whole region between the electrode and the tube exit. The propagation velocity and the distance traveled by the front of the ionization wave outside the tube in the downstream side are consistent with the present experimental measurements. In comparison with the

  20. Determination of Transport Properties From Flowing Fluid Temperature LoggingIn Unsaturated Fractured Rocks: Theory And Semi-Analytical Solution

    SciTech Connect

    Mukhopadhyay, Sumit; Tsang, Yvonne W.

    2008-08-01

    Flowing fluid temperature logging (FFTL) has been recently proposed as a method to locate flowing fractures. We argue that FFTL, backed up by data from high-precision distributed temperature sensors, can be a useful tool in locating flowing fractures and in estimating the transport properties of unsaturated fractured rocks. We have developed the theoretical background needed to analyze data from FFTL. In this paper, we present a simplified conceptualization of FFTL in unsaturated fractured rock, and develop a semianalytical solution for spatial and temporal variations of pressure and temperature inside a borehole in response to an applied perturbation (pumping of air from the borehole). We compare the semi-analytical solution with predictions from the TOUGH2 numerical simulator. Based on the semi-analytical solution, we propose a method to estimate the permeability of the fracture continuum surrounding the borehole. Using this proposed method, we estimated the effective fracture continuum permeability of the unsaturated rock hosting the Drift Scale Test (DST) at Yucca Mountain, Nevada. Our estimate compares well with previous independent estimates for fracture permeability of the DST host rock. The conceptual model of FFTL presented in this paper is based on the assumptions of single-phase flow, convection-only heat transfer, and negligible change in system state of the rock formation. In a sequel paper [Mukhopadhyay et al., 2008], we extend the conceptual model to evaluate some of these assumptions. We also perform inverse modeling of FFTL data to estimate, in addition to permeability, other transport parameters (such as porosity and thermal conductivity) of unsaturated fractured rocks.

  1. Determination of transport properties from flowing fluid temperature logging in unsaturated fractured rocks: Theory and semi-analytical solution

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sumit; Tsang, Yvonne W.

    2008-10-01

    Flowing fluid temperature logging (FFTL) has recently been proposed as a method to locate flowing fractures. We argue that FFTL, backed up by data from high-precision distributed temperature sensors, can be a useful tool in locating flowing fractures and in estimating the transport properties of unsaturated fractured rocks. We have developed the theoretical background needed to analyze data from FFTL. In this article, we present a simplified conceptualization of FFTL in unsaturated fractured rock and develop a semi-analytical solution for spatial and temporal variations of pressure and temperature inside a borehole in response to an applied perturbation (pumping of air from the borehole). We compare the semi-analytical solution with predictions from the TOUGH2 numerical simulator. On the basis of the semi-analytical solution, we propose a method to estimate the permeability of the fracture continuum surrounding the borehole. Using this proposed method, we estimated the effective fracture continuum permeability of the unsaturated rock hosting the Drift Scale Test (DST) at Yucca Mountain, Nevada. Our estimate compares well with previous independent estimates for fracture permeability of the DST host rock. The conceptual model of FFTL presented in this article is based on the assumptions of single-phase flow, convection-only heat transfer, and negligible change in system state of the rock formation. In a sequel article, we extend the conceptual model to evaluate some of these assumptions. In that paper, we also perform inverse modeling of FFTL data to estimate, in addition to permeability, other transport parameters (such as porosity and thermal conductivity) of unsaturated fractured rocks.

  2. The Effect of transient change in strain rate on plastic flow behaviour of Al-Mg-Si alloy at elevated temperatures

    SciTech Connect

    Petrov, P.; Voronkov, V.; Potapenko, K.; Ivanov, V.

    2011-05-04

    In extrusion forging processes, the abrupt changes in strain rate follows the plastic deformation of a material within the deforming zone. To simulate accurately this effect, the specific experimental investigation of the plastic flow during the transient change in strain rate should be performed. The present paper deals with the investigation of this effect on the flow stress of an Al-Mg-Si alloy during its deformation at 350 deg. C. The investigation consists of two steps. Both steps are connected to the monotonic uniaxial compression loading of a cylindrical specimen. During the first step the flow behaviour of the alloy is investigated at the constant strain rate wihin the range of 0.1-50 s{sup -1} at the temperature range of 350-430 deg. C. During the second step the strain rate is abruptly increased or decreased from its current value at a fixed engineering strain of 17-21%. From the beginning of the test up to the strain of 17-21% the value of the strain rate is constant and equal to either 1 s{sup -1} or 10 s{sup -1}. At the strain of 17-21% the value of a strain rate is either increased to 10 s{sup -1} or decreased to 1 s{sup -1}.The results of the experimental investigations were used to determine the isothermal flow stress-strain curves of the Al-Mg-Si alloy as well as the heat effect of plastic deformation of the alloy. On basis of these curves, the strain rate sensitivity index m as a function of true strain and temperature was determined. This parameter allows to optimize a technological process of hot forging of the aluminium alloy as well as it is very important data for the construction of a phenomenological flow stress model.

  3. The Effect of transient change in strain rate on plastic flow behaviour of Al-Mg-Si alloy at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Petrov, P.; Voronkov, V.; Potapenko, K.; Ivanov, V.

    2011-05-01

    In extrusion forging processes, the abrupt changes in strain rate follows the plastic deformation of a material within the deforming zone. To simulate accurately this effect, the specific experimental investigation of the plastic flow during the transient change in strain rate should be performed. The present paper deals with the investigation of this effect on the flow stress of an Al-Mg-Si alloy during its deformation at 350° C. The investigation consists of two steps. Both steps are connected to the monotonic uniaxial compression loading of a cylindrical specimen. During the first step the flow behaviour of the alloy is investigated at the constant strain rate wihin the range of 0.1-50 s-1 at the temperature range of 350-430° C. During the second step the strain rate is abruptly increased or decreased from its current value at a fixed engineering strain of 17-21%. From the beginning of the test up to the strain of 17-21% the value of the strain rate is constant and equal to either 1 s-1 or 10 s-1. At the strain of 17-21% the value of a strain rate is either increased to 10 s-1 or decreased to 1 s-1. The results of the experimental investigations were used to determine the isothermal flow stress-strain curves of the Al-Mg-Si alloy as well as the heat effect of plastic deformation of the alloy. On basis of these curves, the strain rate sensitivity index m as a function of true strain and temperature was determined. This parameter allows to optimize a technological process of hot forging of the aluminium alloy as well as it is very important data for the construction of a phenomenological flow stress model.

  4. The use of fluid inclusions to constrain fault zone pressure, temperature and kinematic history: an example from the Alpi Apuane, Italy

    NASA Astrophysics Data System (ADS)

    Hodgkins, Margaret A.; Stewart, Kevin G.

    1994-01-01

    The Alpi Apuane is a tectonic window that exposes ductilely deformed greenschist facies metaigneous and metasedimentary rocks beneath relatively unmetamorphosed, brittlely deformed sedimentary rocks of the Tuscan nappe. The brecciated fault zone, the 'window fault', separating the two tectonic units was originally described as a simple thrust fault, but has recently been interpreted to have been reactivated as a later extensional detachment. Although evidence for extensional faulting is seen above and below the window fault, the amount of extensional displacement along this fault is unclear. Fluid inclusions from veins cementing the fault breccia were used to estimate the pressures and temperatures during the last fault movement. Minimum pressure estimates obtained from these inclusions range from 105 to 240 MPa. Pressure-corrected trapping temperatures for these fluids range from about 300 to 345°C. These pressures and temperatures indicate that the fault was last active at a depth of about 10 km, assuming a geothermal gradient at the time of 31°C km-1. This rules out complete extensional unroofing of the Alpi Apuane by movement along the window fault. Fluid salinities increase abruptly from the footwall into the fault zone. This pattern suggests that fluids rose from the footwall, entered the fault zone and were channeled within it, leaching salt from the overlying evaporite. The lack of quartz veins above the fault zone indicates that these fluids did not circulate into the overlying Tuscan nappe.

  5. Modeled temperatures and fluid source distributions for the Mexican subduction zone: Effects of hydrothermal circulation and implications for plate boundary seismic processes

    NASA Astrophysics Data System (ADS)

    Perry, Matthew; Spinelli, Glenn A.; Wada, Ikuko; He, Jiangheng

    2016-02-01

    In subduction zones, spatial variations in pore fluid pressure are hypothesized to control the sliding behavior of the plate boundary fault. The pressure-temperature paths for subducting material control the distributions of dehydration reactions, a primary control on the pore fluid pressure distribution. Thus, constraining subduction zone temperatures are required to understand the seismic processes along the plate interface. We present thermal models for three margin-perpendicular transects in the Mexican subduction zone. We examine the potential thermal effects of vigorous fluid circulation in a high-permeability aquifer within the basaltic basement of the oceanic crust and compare the results with models that invoke extremely high pore fluid pressures to reduce frictional heating along the megathrust. We combine thermal model results with petrological models to determine the spatial distribution of fluid release from the subducting slab and compare dewatering locations with the locations of seismicity, nonvolcanic tremor, slow-slip events, and low-frequency earthquakes. Simulations including hydrothermal circulation are most consistent with surface heat flux measurements. Hydrothermal circulation has a maximum cooling effect of 180°C. Hydrothermally cooled crust carries water deeper into the subduction zone; fluid release distributions in these models are most consistent with existing geophysical data. Our models predict focused fluid release, which could generate overpressures, coincident with an observed ultraslow layer (USL) and a region of nonvolcanic tremor. Landward of USLs, a downdip decrease in fluid source magnitude could result in the dissipation in overpressure in the oceanic crust without requiring a downdip increase in fault zone permeability, as posited in previous studies.

  6. Modeled Temperatures and Fluid Source Distributions for the Mexico Subduction Zone: Effects of Hydrothermal Cooling and Implications for Plate Boundary Seismic Processes

    NASA Astrophysics Data System (ADS)

    Perry, M. R.; Spinelli, G. A.; Wada, I.

    2014-12-01

    In subduction zones, spatial variations in pore fluid pressure are hypothesized to control the distribution and nature of slip behavior (e.g., "normal" earthquakes, slow slip events, non-volcanic tremor, very low frequency earthquakes) on the plate boundary fault. A primary control on the pore fluid pressure distribution in subduction zones is the distribution of fluid release from hydrous minerals in the subducting sediment and rock. The distributions of these diagenetic and metamorphic fluid sources are controlled by the pressure-temperature paths that the subducting material follows. Thus, constraining subduction zone thermal structure is required to inform conceptual models of seismic behavior. Here, we present results of thermal models for the Mexico subduction zone, a system that has received recent attention due to observations of slow-slip events and non-volcanic tremor. We model temperatures in five margin-perpendicular transects from 96 ˚W to 104 ˚W. In each transect, we examine the potential thermal effects of vigorous fluid circulation in a high permeability aquifer within the basaltic basement of the oceanic crust. In the transect at 100˚W, hydrothermal circulation cools the subducting material by up to 140 ˚C, shifting peak slab dehydration landward by ~100 km relative to previous estimates from models that do not include the effects of fluid circulation. The age of the subducting plate in the trench increases from ~3 Ma at 104 ˚W to ~18 Ma at 96 ˚W; hydrothermal circulation redistributes the most heat (and cools the system the most) where the subducting plate is youngest. For systems with <20 Ma subducting lithosphere, hydrothermal circulation in oceanic crust should be considered in estimating subduction zone temperatures and fluid source distributions.

  7. Numerical Modeling of Thermofluid Transients During Chilldown of Cryogenic Transfer Lines

    NASA Technical Reports Server (NTRS)

    Majumdar, Alok; Steadman, Todd

    2003-01-01

    The chilldown of fluid transfer lines is an important part of using cryogenic systems such as those found in both ground and space based applications. The chilldown process is a complex combination of both thermal and fluid transient phenomena. A cryogenic liquid flows through a transfer line that is initially at a much higher temperature than the cryogen. Transient heat transfer processes between the liquid and transfer line cause vaporization of the liquid, and this phase change can cause transient pressure and flow surges in the liquid. As the transfer line is cooled, these effects diminish until the liquid reaches a steady flow condition in the chilled transfer line. If these transient phenomena are not properly accounted for in the design process of a cryogenic system, it can lead to damage or failure of system components during operation. For such cases, analytical modeling is desirable for ensuring that a cryogenic system transfer line design is adequate for handling the effects of a chilldown process. The purpose of this paper is to present the results of a numerical model developed using Generalized Fluid System Simulation Program (GFSSP)'s new fluid transient capability in combination with its previously developed thermal transient capability to predict pressure and flow surge in cryogenic transfer lines during a chilldown process. An experiment performed by the National Bureau of Standards (NBS) in 1966 has been chosen as the baseline comparison case for this work. NBS s experimental set-up consisted of a 10.59 cu ft supply dewar, an inlet valve, and a 200 ft long, - in Outside Diameter (OD) vacuum jacketed copper transfer line that exhausted to atmosphere. Three different inlet valves, a - in port ball valve, a 1 in port globe valve and a 1 in port gate valve, were used in NBS s experiments. Experiments were performed using both liquid hydrogen and liquid nitrogen as the fluids. The proposed paper will include detailed comparisons of GFSSP s predictions

  8. Fluid-inclusion evidence for previous higher temperatures in the SUNEDCO 58-28 drill hole near Breitenbush hot springs, Oregon

    USGS Publications Warehouse

    Bargar, Keith E.

    1993-01-01

    The SUNEDCO 58-28 geothermal exploration drill hole was completed in 1981 to a depth of 2, 457 m near Breitenbush Hot Springs in the Western Cascade Mountains of northern Oregon. One hundred thirteen liquid-rich fluid inclusions (mostly secondary) were analyzed from drill cuttings samples of hydrothermal quartz, calcite, and anhydrite, as well as primary quartz phenocrysts. Except for one hydrothermal quartz specimen, minimum homogenization temperature (Th) measurements of fluid inclusions plot very close to the present measured temperatures for the drill hole. Fluid-inclusion data from near the bottom of the drill hole suggest that these rocks were altered by water of significantly greater salinity than Breitenbush Hot Springs water.

  9. Effect of temperature-dependency of Newtonian and non-Newtonian fluid properties on the dynamics of droplet impinging on hot surfaces

    NASA Astrophysics Data System (ADS)

    Binesh, A. R.; Mousavi, S. M.; Kamali, R.

    2015-02-01

    In the present work, three-dimensional computational fluid dynamics analysis is employed to study the droplet dynamics of Newtonian and non-Newtonian droplets impinging on a hot surface under various impact conditions. The Navier-Stokes equations for unsteady, incompressible, and viscous fluid flow are solved using a control volume method. The volume-of-fluid (VOF) technique is also used to track the free-surface of the liquid. The effect of viscosity, density and surface tension on droplet dynamics is evaluated considering their dependence of temperature. The results indicate that the temperature dependence of the both Newtonian and non-Newtonian physicochemical liquid properties must be considered to obtain better agreement of the numerical results with experimental data. After ensuring the accuracy of the numerical methodology, the internal behavior of the droplets is examined, which is shown that the receding velocity of the non-Newtonian droplet is slower than the Newtonian one.

  10. Analyses of ACPL thermal/fluid conditioning system

    NASA Technical Reports Server (NTRS)

    Stephen, L. A.; Usher, L. H.

    1976-01-01

    Results of engineering analyses are reported. Initial computations were made using a modified control transfer function where the systems performance was characterized parametrically using an analytical model. The analytical model was revised to represent the latest expansion chamber fluid manifold design, and systems performance predictions were made. Parameters which were independently varied in these computations are listed. Systems predictions which were used to characterize performance are primarily transient computer plots comparing the deviation between average chamber temperature and the chamber temperature requirement. Additional computer plots were prepared. Results of parametric computations with the latest fluid manifold design are included.

  11. Resolving Histories of Magmatic Volatiles in Fluids and Silicate Melts as a Function of Pressure, Temperature, and Melt Composition through Apatite Geochemistry

    NASA Astrophysics Data System (ADS)

    Webster, J. D.; Piccoli, P. M.; Goldoff, B. A.

    2012-12-01

    Fluids including aqueous or aqueous-carbonic vapor, aqueous liquid, and hydrosaline liquid, if present in magma, influence magmatic and volcanic processes, and the exsolution of fluids from magma sequesters and buffers volatile components from melt thus impacting the textural and chemical evolution of melts and phenocrysts. Establishing the timing of initial magmatic fluid saturation and monitoring changes in fluid chemistry through textural interpretations are often challenging because primary magmatic fluid inclusions are uncommon to most plutonic systems and are extremely rare in phenocrysts of eruptive magmas. Moreover, miarolitic cavities, often interpreted to be a priori evidence of fluid exsolution, are rarely observed in igneous systems. Geochemical tools used to resolve magmatic volatile histories include the analysis and interpretation of melt inclusion compositions and those of hydrous minerals including micas, amphiboles, and apatite. We have conducted more than 50 new hydrothermal experiments involving apatite+rhyodacite melt±fluids at 28, 50, 100, 200, and 400 MPa, and have combined these new data with published results for apatite-saturated melts at 200 MPa. This integrated body of data supports determination of a broadly applicable geochemical relationship that correlates the mole fractions of H2O and Cl in apatite with mole fractions of H2O and Cl in coexisting silicate melt as a function of pressure, temperature, and melt composition (for felsic to basaltic melts). The mathematical expression of this relationship is useful for a wide variety of applications: constraining H2O, Cl, and F concentrations in silicate melts and hence verifying concentrations of magmatic volatiles determined from silicate melt inclusions; establishing pressures or temperatures of apatite crystallization or last equilibration with melt ± fluids (if temperature and pressure, respectively, are constrained from other geothermobarometers); determining concentrations of

  12. Wellbore fluid

    SciTech Connect

    Swanson, B.L.

    1984-06-19

    The water loss properties of well completion and well workover fluids are improved by the addition of an effective amount of at least one adjuvant selected from (1) sodium carbonate with either sodium bicarbonate or an organic polycarboxylic acid or polycarboxylic acid anhydride or (2) sodium bicarbonate alone. In another embodiment, the adjuvants are added to stabilize water loss control agents in wellbore fluids, especially at elevated temperatures.

  13. Verification and validation of COBRA-SFS transient analysis capability

    SciTech Connect

    Rector, D.R.; Michener, T.E.; Cuta, J.M.

    1998-05-01

    This report provides documentation of the verification and validation testing of the transient capability in the COBRA-SFS code, and is organized into three main sections. The primary documentation of the code was published in September 1995, with the release of COBRA-SFS, Cycle 2. The validation and verification supporting the release and licensing of COBRA-SFS was based solely on steady-state applications, even though the appropriate transient terms have been included in the conservation equations from the first cycle. Section 2.0, COBRA-SFS Code Description, presents a capsule description of the code, and a summary of the conservation equations solved to obtain the flow and temperature fields within a cask or assembly model. This section repeats in abbreviated form the code description presented in the primary documentation (Michener et al. 1995), and is meant to serve as a quick reference, rather than independent documentation of all code features and capabilities. Section 3.0, Transient Capability Verification, presents a set of comparisons between code calculations and analytical solutions for selected heat transfer and fluid flow problems. Section 4.0, Transient Capability Validation, presents comparisons between code calculations and experimental data obtained in spent fuel storage cask tests. Based on the comparisons presented in Sections 2.0 and 3.0, conclusions and recommendations for application of COBRA-SFS to transient analysis are presented in Section 5.0.

  14. Fluid-assisted particulate flow of turbidites at very low temperature: A key to tight folding in a submarine Variscan foreland basin of SW Europe

    NASA Astrophysics Data System (ADS)

    Marques, F. O.; Burg, J.-P.; Lechmann, S. M.; Schmalholz, S. M.

    2010-04-01

    The problem addressed in this article is how sedimentary formations like turbidites in a foreland basin, which include layers with apparently great competence contrast, can be tightly folded in a regular manner under very low temperature and pressure. This raises two major issues: the rheological behavior of the rocks at the time of folding and the role played by fluids. In order to understand very low temperature folding and the structural evolution of a submarine foreland basin, we carried out detailed structural work in turbidites with alternating sandstone and shale, for which estimated peak temperature conditions were top diagenetic to very low grade metamorphism. Folds are tight to isoclinal, with local collapsed hinges, which implies that the incompetent shale was mobile enough to flow away from strongly flattened areas. We did not find evidence for cataclastic flow or crystal plasticity at mesoscopic and microscopic scales. Other structures (mostly boudins, foliations, conjugate brittle faults, and quartz veins) associated with folds denote anisotropic compaction by fluid extraction during regional shortening. This is possible if the folded rocks were unconsolidated, fluid-saturated sediments. The estimated low peak temperature is consistent with the shale being unlithified. Poorly cemented grains are free to slide past one another under shallow burial or high pore pressure conditions. Following this line of thought, we consider independent particulate flow assisted by fluids under very low confining pressure (bean bag analogy) as the rock deformation mechanism active during the described intense folding. Similar deformation is likely occurring (and has occurred) in other submarine accretionary wedges.

  15. An in situ experimental study of Zr4+ transport capacity of water-rich fluids in the temperature and pressure range of the deep crust and upper mantle

    NASA Astrophysics Data System (ADS)

    Mysen, Bjorn

    2015-12-01

    Throughout the Earth's history, mass transport involved fluids. In order to address the circumstances under which Zr4+ may have been transported in this manner, its solubility behavior in aqueous fluid with and without NaOH and SiO2 in equilibrium with crystalline ZrO2 was determined from 550 to 950 °C and 60 to 1200 MPa. The measurements were carried out in situ while the samples were at the temperatures and pressures of interest. In ZrO2-H2O and ZrO2-SiO2-H2O fluids, the Zr4+ concentration ranges from ≤10 to ~70 ppm with increasing temperature and pressure. Addition of SiO2 to the ZrO2-H2O system does not affect these values appreciably. In these two environments, Zr4+ forms simple oxide complexes in the H2O fluid with ∆H ~ 40 kJ/mol for the solution equilibrium, ZrO2(solid) = ZrO2(fluid). The Zr4+ concentration in aqueous fluid increases about an order of magnitude upon addition of 1 M NaOH, which reflects the formation of zirconate complexes. The principal solution mechanism is ZrO2 + 4NaOH = Na4ZrO4 + 2H2O with ∆H ~ 200 kJ/mol. Addition of both SiO2 and NaOH to ZrO2-H2O enhances the Zr4+ by an additional factor of about 5 with the formation of partially protonated alkali zircon silicate complexes in the fluid. The principal solution mechanism is 2ZrO2 + 2NaOH + 2SiO2 = Na2Zr2Si2O9 + H2O with ∆H ~ 40 kJ/mol. These results, in combination with other published experimental data, imply that fluid released during high-temperature/high-pressure dehydration of hydrous mineral assemblages in the Earth's interior under some circumstances may carry significant concentrations of Zr and probably other high field strength elements (HFSEs). This suggestion is consistent with the occurrence of Zr-rich veins in high-grade metamorphic eclogite and granulite terranes. Moreover, aqueous fluids transported from dehydrating oceanic crust into overlying mantle source rocks of partial melting also may carry high-abundance HFSE of fluids released from dehydrating slabs and

  16. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    DOE PAGESBeta

    Wang, Hsiu -Wen; Fanelli, Victor R.; Reiche, Helmut M.; Larson, Eric; Taylor, Mark A.; Xu, Hongwu; Zhu, Jinlong; Siewenie, Joan; Page, Katharine

    2014-12-01

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO2measurements. Asmore » a result, the new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H2 and natural gas uptake/storage.« less

  17. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    SciTech Connect

    Wang, Hsiu-Wen; Fanelli, Victor R.; Reiche, Helmut M.; Larson, Eric; Taylor, Mark A.; Siewenie, Joan; Xu, Hongwu; Zhu, Jinlong; Page, Katharine

    2014-12-15

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO{sub 2} measurements. The new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO{sub 2} sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H{sub 2} and natural gas uptake/storage.

  18. Unlocking the potential of supported liquid phase catalysts with supercritical fluids: low temperature continuous flow catalysis with integrated product separation

    PubMed Central

    Franciò, Giancarlo; Hintermair, Ulrich; Leitner, Walter

    2015-01-01

    Solution-phase catalysis using molecular transition metal complexes is an extremely powerful tool for chemical synthesis and a key technology for sustainable manufacturing. However, as the reaction complexity and thermal sensitivity of the catalytic system increase, engineering challenges associated with product separation and catalyst recovery can override the value of the product. This persistent downstream issue often renders industrial exploitation of homogeneous catalysis uneconomical despite impressive batch performance of the catalyst. In this regard, continuous-flow systems that allow steady-state homogeneous turnover in a stationary liquid phase while at the same time effecting integrated product separation at mild process temperatures represent a particularly attractive scenario. While continuous-flow processing is a standard procedure for large volume manufacturing, capitalizing on its potential in the realm of the molecular complexity of organic synthesis is still an emerging area that requires innovative solutions. Here we highlight some recent developments which have succeeded in realizing such systems by the combination of near- and supercritical fluids with homogeneous catalysts in supported liquid phases. The cases discussed exemplify how all three levels of continuous-flow homogeneous catalysis (catalyst system, separation strategy, process scheme) must be matched to locate viable process conditions. PMID:26574523

  19. Unlocking the potential of supported liquid phase catalysts with supercritical fluids: low temperature continuous flow catalysis with integrated product separation.

    PubMed

    Franciò, Giancarlo; Hintermair, Ulrich; Leitner, Walter

    2015-12-28

    Solution-phase catalysis using molecular transition metal complexes is an extremely powerful tool for chemical synthesis and a key technology for sustainable manufacturing. However, as the reaction complexity and thermal sensitivity of the catalytic system increase, engineering challenges associated with product separation and catalyst recovery can override the value of the product. This persistent downstream issue often renders industrial exploitation of homogeneous catalysis uneconomical despite impressive batch performance of the catalyst. In this regard, continuous-flow systems that allow steady-state homogeneous turnover in a stationary liquid phase while at the same time effecting integrated product separation at mild process temperatures represent a particularly attractive scenario. While continuous-flow processing is a standard procedure for large volume manufacturing, capitalizing on its potential in the realm of the molecular complexity of organic synthesis is still an emerging area that requires innovative solutions. Here we highlight some recent developments which have succeeded in realizing such systems by the combination of near- and supercritical fluids with homogeneous catalysts in supported liquid phases. The cases discussed exemplify how all three levels of continuous-flow homogeneous catalysis (catalyst system, separation strategy, process scheme) must be matched to locate viable process conditions. PMID:26574523

  20. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: probing atomic structure in situ.

    PubMed

    Wang, Hsiu-Wen; Fanelli, Victor R; Reiche, Helmut M; Larson, Eric; Taylor, Mark A; Xu, Hongwu; Zhu, Jinlong; Siewenie, Joan; Page, Katharine

    2014-12-01

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO2 measurements. The new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H2 and natural gas uptake/storage. PMID:25554335