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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. A High-Temperature Transient Hot-Wire Thermal Conductivity Apparatus for Fluids.

    PubMed

    Perkins, R A; Roder, H M; Nieto de Castro, C A

    1991-01-01

    A new apparatus for measuring both the thermal conductivity and thermal diffusivity of fluids at temperatures from 220 to 775 K at pressures to 70 MPa is described. The instrument is based on the step-power-forced transient hot-wire technique. Two hot wires are arranged in different arms of a Wheatstone bridge such that the response of the shorter compensating wire is subtracted from the response of the primary wire. Both hot wires are 12.7 µm diameter platinum wire and are simultaneously used as electrical heat sources and as resistance thermometers. A microcomputer controls bridge nulling, applies the power pulse, monitors the bridge response, and stores the results. Performance of the instrument was verified with measurements on liquid toluene as well as argon and nitrogen gas. In particular, new data for the thermal conductivity of liquid toluene near the saturation line, between 298 and 550 K, are presented. These new data can be used to illustrate the importance of radiative heat transfer in transient hot-wire measurements. Thermal conductivity data for liquid toluene, which are corrected for radiation, are reported. The precision of the thermal conductivity data is ± 0.3% and the accuracy is about ±1%. The accuracy of the thermal diffusivity data is about ± 5%. From the measured thermal conductivity and thermal diffusivity, we can calculate the specific heat, Cp , of the fluid, provided that the density is measured, or available through an equation of state.

  3. Transient, radial temperature distribution in a porous medium during fluid injection

    SciTech Connect

    Dunn, J.C.; Nilson, R.H.

    1982-01-01

    Analytical and numerical solutions are presented for the transient, radial temperature distribution in a porous medium which is subjected to a constant-rate injection of an incompressible fluid from a wellbore. The formulation includes energy transfer by conduction and convection, and the Danckwerts boundary condition is applied at the finite-radius wellbore. At late times, the numerical solutions approach a self-similar form which can be described in terms of the incomplete Gamma function. In typical petroleum and geothermal applications, convergence to the asymptotic similarity solutions occurs on a time scale of roughly one hour. The results are generally applicable to a broad range of convection-diffusion phenomena which are best described in radial coordinates.

  4. Fluid pressure and temperature transients detected at the Nankai Trough Megasplay Fault: Results from the SmartPlug borehole observatory

    NASA Astrophysics Data System (ADS)

    Hammerschmidt, S.; Davis, E. E.; Kopf, A.

    2013-07-01

    The SmartPlug is the first borehole observatory in the IODP Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE). It comprises a retrievable bridge plug with an autonomous instrument for pressure (P) and temperature (T) monitoring. The borehole observatory was installed at Site C0010 of the Integrated Ocean Drilling Program (IODP) Kumano transect crossing the Nankai Trough, SE offshore Japan, to obtain fluid pressure and temperature data from where the borehole penetrates one of the shallow branches of the subduction megasplay fault at 410 mbsf. In this manuscript, a 15 month-long P-T record collected by the SmartPlug is evaluated. Despite the 1 min sampling interval, pressure variations related to local storms and to tsunami and seismic waves from regional and distant earthquakes are observed. Seismic waves of one regional earthquake appear to have led to a drop in formation pressure that may be the consequence of a seismic-wave-induced increase in permeability. Pressure variations related to Rayleigh waves are typically larger in the formation than in the inadvertently sealed casing above, whereas seafloor loading signals imposed by tides, tsunamis, and storm-generated waves are larger in the casing than in the formation. This difference presumably reflects the different response to strain generated by formation deformation vs. strain caused by loading at the seafloor. No seismogenic or aseismic deformation event at the megasplay fault or within the accretionary prism was observed during this initial 15-month-long recording period. A SmartPlug observatory monitored the Nankai Trough Megasplay Fault for 15 months. In situ borehole pressure (P) and temperature (T) data were collected and evaluated. After the data were de-tided and filtered, several P transients were detected. P transients were caused by storm-induced microseism, seismic and tsunami waves. No indications for recent activity of the Megasplay Fault were found.

  5. Transient cavitation in fluid-structure interactions

    SciTech Connect

    Kot, C.A.; Hsieh, B.J.; Youngdahl, C.K.; Valentin, R.A.

    1981-11-01

    A generalized column separation model is extended to predict transient cavitation associated with fluid-structure interactions. The essential feature of the combined fluid-structure interaction calculations is the coupling between the fluid transient, which is computed one dimensionally, and the structural response which can be multidimensional. Proper coupling is achieved by defining an average, one-dimensional, structural velocity and by assuming a spatially uniform pressure loading of the structure. This procedure is found to be effective even for complex finite element structural models for which the required computational time step is orders of magnitude smaller than that for the fluid transient. Computational examples and comparison with experimental data show that neglecting cavitation and setting the fluid velocity at all times equal to that of the structural boundary leads to unreal negative pressure predictions. A properly coupled column separation model reproduces the important features of fluid-structure interactions, converges rapidly, and gives reasonable fluid and structural response predictions. 9 refs.

  6. Transient thermal analysis of fluid systems

    NASA Technical Reports Server (NTRS)

    Chandler, G. D.; Trust, R. D.

    1977-01-01

    Computer program performs transient thermal analysis of any 2-node to 200-node-thermal network, which transports heat by fluid flow convection. Program can be modified to add conduction along tubes and radiation.

  7. General Transient Fluid Flow Algorithm

    SciTech Connect

    Amsden, A. A.; Ruppel, H. M.; Hirt, C. W.

    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 results 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.

  8. 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.

  9. Fluid transients in fluid-structure interaction - 1985

    SciTech Connect

    Dodge, F.T.; Moody, F.J.

    1985-01-01

    This book presents the papers given at a conference which considered fluid flow in reactor cooling systems. Topics covered at the conference included computerized simulation, pressure surges, transient flow in piping, steam condensation in water, BWR type reactors, PWR type reactors, relief valves, shock waves, control elements, zero gravity in spacecraft, two-phase flow, steam turbines, and turbulent flow.

  10. 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.

  11. Transient fluid flow and heat transfer in petroleum production systems

    NASA Astrophysics Data System (ADS)

    Lin, Dongqing

    Heat transfer is an important phenomenon in both wellbore and reservoir. The pertinent temperature distribution can provide a valuable perspective in analyzing and optimizing the oil production. In this work, two kinds of co-production, production fluid through the annulus and tubing, and through two independent tubings, have been modeled using steady state analysis. The fluid temperatures in the production string and annulus have been solved analytically in both cases. Furthermore, we extended the theory of steady state energy transport to remedy asphaltene deposition problem by circulating the cooling fluid in the annulus. Due to the complex nature of two-phase flow in the oil/gas production, more reliable mechanistic modeling approaches have been developed since early 1980's. Rooted in Hasan-Kabir model, we have developed a wellbore/reservoir coupling simulator for the transient non-Darcy two-phase flow in the flow-after-flow well test. The entire historical flow behavior has been modeled using superposition method and validated with field data. Our second simulation is for the investigation of a blowout well, which is a great concern in the oil field. When the pressure in the wellbore is sufficiently high, the fluids will attain sonic velocity at the wellhead. We presented a computational algorithm to estimate the blowout rate in a given wellbore/reservoir system and examined four major parameters, such as formation permeability, Gas-Oil-Ratio (GOR), reservoir pressure and tubing diameter. The transient nature of this approach also illustrates the evolution process of a blowout. We have also developed a transient simulator to determine the location and severity of a blockage in a gas pipeline based on the theory of two-phase flow and pressure transient analysis. The presence of a sizeable blockage will affect the outlet gas pressure response by decreasing the available pipe volume and increasing the friction loss of the fluid flow. The simulator solves for the

  12. Transient thermohydraulic modeling of two-phase fluid systems

    NASA Astrophysics Data System (ADS)

    Blet, N.; Delalandre, N.; Ayel, V.; Bertin, Y.; Romestant, C.; Platel, V.

    2012-11-01

    This paper presents a transient thermohydraulic modeling, initially developed for a capillary pumped loop in gravitational applications, but also possibly suitable for all kinds of two-phase fluid systems. Using finite volumes method, it is based on Navier-Stokes equations for transcribing fluid mechanical aspects. The main feature of this 1D-model is based on a network representation by analogy with electrical. This paper also proposes a parametric study of a counterflow condenser following the sensitivity to inlet mass flow rate and cold source temperature. The comparison between modeling results and experimental data highlights a good numerical evaluation of temperatures. Furthermore, the model is able to represent a pretty good dynamic evolution of hydraulic variables.

  13. 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.

  14. The transient performance of a two-phase fluid reservoir

    NASA Technical Reports Server (NTRS)

    Chi, Joseph

    1989-01-01

    Thermal control of future large, high power spacecraft will require a two-phase fluid central bus. The two-phase fluid reservoir is a critical component in the two-phase fluid bus. It both controls the saturation temperature and provides a space for volumetric changes. A dynamic reservoir simulation model does not currently exist, but it is needed to expedite efforts and reduce risk. During 1989 an effort was made to develop a simulation model of the transient performance of a two-phase fluid reservoir. As a beginning, a preliminary model was developed. It is based upon component mathematical models in lumped parametric form and build upon five component mathematical models for calculating dynamic responses of two-phase fluid reservoirs, primary feedback elements, controller commands, heater actuators, and reservoir heaters. As much as possible, the model took advantage of the available SINDA'85/FLUINT thermal/fluid integrator. Additional calculation logic and computer subroutines were developed to complete implementation of the model. The model is capable of simulating dynamic response of an equilibrium two-phase fluid reservoir. Modification of the model to include the liquid/vapor nonequilibrium is required for applications of the model to simulate performance of reservoir in which the liquid and vapor phases of the reservoir fluid are not in equilibrium. In addition, the model in its present form, needs to be refined in several respects. More empirical data are needed to guide the model development. The model may then be used to conduct a full parametric study of two-phase fluid reservoirs. More complexities in two-phaes flow regions in laboratory and flight conditions may have to be considered eventually if empirical data cannot be simulated satisfactorily. System with other components arrangement also need to be simulated if optimization is ever to be attained. The present model does, however, preliminarily demonstrates that such analyses are quite possible

  15. 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.

  16. 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.

  17. Accurate measurement of unsteady state fluid temperature

    NASA Astrophysics Data System (ADS)

    Jaremkiewicz, Magdalena

    2017-03-01

    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.

  18. 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.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. 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.

  2. 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

  3. Transient Shear Banding in a Simple Yield Stress Fluid

    NASA Astrophysics Data System (ADS)

    Divoux, Thibaut; Tamarii, David; Barentin, Catherine; Manneville, Sébastien

    2010-05-01

    We report a large set of experimental data which demonstrates that a simple yield stress fluid, i.e., which does not present aging or thixotropy, exhibits transient shear banding before reaching a steady state characterized by a homogeneous, linear velocity profile. The duration of the transient regime decreases as a power law with the applied shear rate γ˙. This power-law behavior, observed here in carbopol dispersions, does not depend on the gap width and on the boundary conditions for a given sample preparation. For γ˙≲0.1s-1, heterogeneous flows could be observed for as long as 105s. These local dynamics account for the ultraslow stress relaxation observed at low shear rates.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Simulation and experiment on transient temperature field of a magnetorheological clutch for vehicle application

    NASA Astrophysics Data System (ADS)

    Wang, Daoming; Zi, Bin; Zeng, Yishan; Qian, Sen; Qian, Jun

    2017-09-01

    The unpredictable power fluctuation due to severe heating has been demonstrated to be a critical bottleneck technique restricting the application of magnetorheological (MR) clutches in vehicle industry. The aim of this study is to introduce a low-cost transient simulation approach for evaluating the heat build-up and dissipation of a liquid-cooled MR vehicle clutch. This paper firstly performs a detailed description of the developed MR clutch in terms of operation principle, material selection and configuration. Subsequently, transient temperature simulations are carried out under various conditions to reveal the distribution, variation and impact factors of the transient temperature field. Following these, an experimental setup is established for heating tests of the clutch prototype. Experimental results concerning the temperature variation of magnetorheological fluids and the maximum allowable transient slip power of the clutch prototype are presented, which in return verify the correctness and feasibility of the simulation.

  10. In vitro comparison of output fluid temperatures for room temperature and prewarmed fluids.

    PubMed

    Soto, N; Towle Millard, H A; Lee, R A; Weng, H Y

    2014-08-01

    To determine if prewarmed intravenous fluids produce superior fluid output temperatures compared with room temperature fluids at common anaesthetic fluid rates for small animal patients. A prospective, randomised, in vitro fluid line test-vein study was performed. Nine flow rates were analysed (10, 20, 60, 100, 140, 180, 220, 260 and 300 mL/hour) for room temperature fluids (21°C) and for five prewarmed fluids (40, 45, 50, 55 and 60°C). For each flow rate tested, room temperature fluids never exceeded 25°C at any time point for each trial (range 18 to 25°C). For each flow rate tested, prewarmed fluids never exceeded 25 · 5°C at any time point for each trial (range 18 to 25 · 5°C). The mean output fluid temperature of prewarmed fluids was significantly warmer than room temperature fluids only at 300 mL/hour for 40°C (P = 0 · 0012), 45°C (P = 0 · 004), 50°C (P = 0 · 0002), 55°C (P = 0 · 0001) and 60°C (P < 0 · 0001). There was no thermodynamic benefit to utilising prewarmed intravenous fluids (up to 60°C) compared with room temperature intravenous fluids at common anaesthetic fluid rates for small animals. © 2014 British Small Animal Veterinary Association.

  11. Transient computation fluid dynamics modeling of a single proton exchange membrane fuel cell with serpentine channel

    NASA Astrophysics Data System (ADS)

    Hu, Guilin; Fan, Jianren

    The proton exchange membrane fuel cell (PEMFC) has become a promising candidate for the power source of electrical vehicles because of its low pollution, low noise and especially fast startup and transient responses at low temperatures. A transient, three-dimensional, non-isothermal and single-phase mathematical model based on computation fluid dynamics has been developed to describe the transient process and the dynamic characteristics of a PEMFC with a serpentine fluid channel. The effects of water phase change and heat transfer, as well as electrochemical kinetics and multicomponent transport on the cell performance are taken into account simultaneously in this comprehensive model. The developed model was employed to simulate a single laboratory-scale PEMFC with an electrode area about 20 cm 2. The dynamic behavior of the characteristic parameters such as reactant concentration, pressure loss, temperature on the membrane surface of cathode side and current density during start-up process were computed and are discussed in detail. Furthermore, transient responses of the fuel cell characteristics during step changes and sinusoidal changes in the stoichiometric flow ratio of the cathode inlet stream, cathode inlet stream humidity and cell voltage are also studied and analyzed and interesting undershoot/overshoot behavior of some variables was found. It was also found that the startup and transient response time of a PEM fuel cell is of the order of a second, which is similar to the simulation results predicted by most models. The result is an important guide for the optimization of PEMFC designs and dynamic operation.

  12. 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.

  13. 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.

  14. 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.

  15. Temperature dependence of nucleation in Yukawa fluids

    NASA Astrophysics Data System (ADS)

    Li, J.-S.; Wilemski, G.

    2002-03-01

    We have studied the temperature dependence of gas-liquid nucleation in Yukawa fluids with gradient theory (GT) and density functional theory (DFT). Each of these nonclassical theories exhibits a weaker (i.e. better) temperature dependence than classical nucleation theory. At a given temperature, the difference between GT and DFT for the reversible work to form a critical nucleus gets smaller with increasing superaturation. For the temperature dependence, the reversible work for GT is very close to that for DFT at high temperatures. The difference between the two theories increases with decreasing temperature and supersaturation. Thus, in contrast to the behavior of a Peng-Robinson fluid, we find that GT can improve the temperature dependence over that of classical nucleation theory, although not always to the same degree as DFT.

  16. 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.

  17. Relatively simple, precise methods to analyze temperature transients in ectotherms.

    PubMed

    Voss, M A.; Reed Hainsworth, F

    2001-04-01

    Relatively complex core-shell models have been used to precisely characterize times and temperatures for ectotherms. There is a simpler method using a second-order analysis of heat flux. We derive the method from an equivalent mechanical system, correct some previously published inaccuracies, and show how to use the method by analyzing thermal transients for House Wren eggs under natural conditions.

  18. 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.

  19. 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.

  20. 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.

  1. Transient performance and temperature field of a natural convection air dehumidifier loop

    NASA Astrophysics Data System (ADS)

    Fazilati, Mohammad Ali; Sedaghat, Ahmad; Alemrajabi, Ali-Akbar

    2017-02-01

    In this paper, transient performance of the previously introduced natural convection heat and mass transfer loop is investigated for an air dehumidifier system. The performance of the loop is studied in different conditions of heat source/heat sink temperature and different startup desiccant concentrations. Unlike conventional loops, it is observed that natural convection of the fluid originates from the heat sink towards the heat source. The proper operation of the cycle is highly dependent on the heat sink/heat source temperatures. To reduce the time constant of the system, a proper desiccant concentration should be adopted for charge of the loop.

  2. Transient performance and temperature field of a natural convection air dehumidifier loop

    NASA Astrophysics Data System (ADS)

    Fazilati, Mohammad Ali; Sedaghat, Ahmad; Alemrajabi, Ali-Akbar

    2017-07-01

    In this paper, transient performance of the previously introduced natural convection heat and mass transfer loop is investigated for an air dehumidifier system. The performance of the loop is studied in different conditions of heat source/heat sink temperature and different startup desiccant concentrations. Unlike conventional loops, it is observed that natural convection of the fluid originates from the heat sink towards the heat source. The proper operation of the cycle is highly dependent on the heat sink/heat source temperatures. To reduce the time constant of the system, a proper desiccant concentration should be adopted for charge of the loop.

  3. Observations of transient high temperature vortical microstructures in solids during adiabatic shear banding

    NASA Astrophysics Data System (ADS)

    Guduru, P. R.; Ravichandran, G.; Rosakis, A. J.

    2001-09-01

    By using a unique infrared high-speed camera especially constructed for recording highly transient temperature fields at the microscale, we are able to reveal the spatial and temporal microstructure within dynamically growing shear bands in metals. It is found that this structure is highly nonuniform and possesses a transient, short range periodicity in the direction of shear band growth in the form of an array of intense ``hot spots'' reminiscent of the well-known, shear-induced hydrodynamic instabilities in fluids. This is contrary to the prevailing classical view that describes the deformations and the temperatures within shear bands as being essentially one-dimensional fields. These observations are also reminiscent of the nonuniform structure of localized shear regions believed to exist, at an entirely different length scale, in the earth's lower crust and upper mantle.

  4. SALE2D. General Transient Fluid Flow Algorithm

    SciTech Connect

    Amsden, A.A.; Ruppel, H.M.; Hirt, C.W.

    1981-06-01

    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 results 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.

  5. 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

  6. Modeling quantum fluid dynamics at nonzero temperatures.

    PubMed

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

    2014-03-25

    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.

  7. 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.

  8. Flow non-normality-induced transient growth in superposed Newtonian and non-Newtonian fluid layers.

    PubMed

    Camporeale, C; Gatti, F; Ridolfi, L

    2009-09-01

    In recent years non-normality and transient growths have attracted much interest in fluid mechanics. Here, we investigate these topics with reference to the problem of interfacial instability in superposed Newtonian and non-Newtonian fluid layers. Under the hypothesis of the lubrication theory, we demonstrate the existence of significant transient growths in the parameter space region where the dynamical system is asymptotically stable, and show how they depend on the main physical parameters. In particular, the key role of the density ratio is highlighted.

  9. Temperature-induced transient noise of pyroelectric thermal detector

    NASA Astrophysics Data System (ADS)

    Lee, Muno; Bae, Seong-Ho

    2000-11-01

    An analysis of temperature-induced transient noise for a thermal detector prepared with Pb(Zr,Ti)O3-Pb(Sb0.5Nb0.5)O3 (PZT-PSN) pyroelectric ceramics as the sensing element is conducted by measuring its oven noise as a function of the junction field-effect transistor (JFET) characteristics, gate resistance, low-temperature heat treatment, chemical composition and the grain size of the pyroelectric ceramic. Pyroelectric wafers are prepared by the mixed oxide technique, and thermal sensors are fabricated with a PZT-PSN ceramic wafer, JFET, chip-type gate resistor, alumina PCB (printed circuit board) and a TO- 5 package with antireflective (AR)-coated Si window. Thermal detector noise depends on the chemical composition of the pyroelectric sensing element. The temperature-induced transient JFET noise varies with its characteristics and gate resistance and is reduced by connecting a pyroelectric sensing element with high capacitance. The pyroelectric ceramic sensing element generates burst noise in the region from 7 to -10 degree(s)C during cooling, which is remarkably reduced by reducing the grain size of the pyroelectric ceramic and/or by cyclic heat treatment at a low temperature. Thus, burst noise as a strong relationship with the elastic energies within the ceramic sensing element and the bonding material between the sensing wafer and the PCB, originating in the different thermal expansion between pyroelectric sensing wafer and alumina PCB.

  10. 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.

  11. 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.

  12. Concrete creep at transient temperature: constitutive law and mechanism

    SciTech Connect

    Chern, J.C.; Bazant, Z.P.; Marchertas, A.H.

    1985-01-01

    A constitutive law which describes the transient thermal creep of concrete is presented. Moisture and temperature are two major parameters in this constitutive law. Aside from load, creep, cracking, and thermal (shrinkage) strains, stress-induced hygrothermal strains are also included in the analysis. The theory agrees with most types of test data which include basic creep, thermal expansion, shrinkage, swelling, creep at cyclic heating or drying, and creep at heating under compression or bending. Examples are given to demonstrate agreement between the theory and the experimental data. 15 refs., 6 figs.

  13. 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.

  14. Improving transaxle performance at low temperature with reduced-viscosity automatic transmission fluids

    SciTech Connect

    Linden, J.L.; Kemp, S.P.

    1987-01-01

    The effects of automatic transmission fluid viscosity on the low-temperature performance of a front-wheel-drive transaxle were determined in a cold room maintained at a temperature of -20/sup 0/F (-28.9/sup 0/C), using both a cranking apparatus and a vehicle. Cranking and vehicle tests were conducted to determine the effects of fluid viscosity on the power required to crack a transaxle and on transaxle performance under low-temperature transient operation, respectively. Four automatic transmission fluids were tested, ranging in viscosity from 2 600 to 16 000 cP at - 20/sup 0/F. All test fluids contained the same additive package and were blended using the same types of base oils.

  15. Transient molecular dynamics simulations of liquid viscosity for nonpolar and polar fluids.

    PubMed

    Thomas, Jason C; Rowley, Richard L

    2011-01-14

    A transient molecular dynamics (TMD) method for obtaining fluid viscosity is extended to multisite, force-field models of both nonpolar and polar liquids. The method overlays a sinusoidal velocity profile over the peculiar particle velocities and then records the transient decay of the velocity profile. The viscosity is obtained by regression of the solution of the momentum equation with an appropriate constitutive equation and initial and boundary conditions corresponding to those used in the simulation. The transient velocity decays observed appeared to include both relaxation and retardation effects. The Jeffreys viscoelastic model was found to model accurately the transient responses obtained for multisite models for n-butane, isobutane, n-hexane, water, methanol, and 1-hexanol. TMD viscosities obtained for saturated liquids over a wide range of densities agreed well for the polar fluids, both with nonequilibrium molecular dynamics (NEMD) results using the same force-field models and with correlations based on experimental data. Viscosities obtained for the nonpolar fluids agreed well with the experimental and NEMD results at low to moderate densities, but underpredicted experimental values at higher densities where shear-thinning effects and viscous heating may impact the TMD simulations.

  16. 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.

  17. Pressure transient behavior of dilatant non-Newtonian/Newtonian fluid composite reservoirs

    SciTech Connect

    Okpobiri, G.A.; Ikoku, C.U.

    1983-11-01

    This study investigates pressure falloff testing in non-Newtonian/Newtonian fluid composite reservoirs. The non-Newtonian fluids of interest exhibit dilatant behavior. Initial water saturation is accounted for. Application of non-Newtonian well test analysis techniques and conventional Horner (Newtonian) techniques is investigated. The effects of different injection times before shut-in, external radii, flow behavior indexes and non-Newtonian fluid consistencies on the pressure transient behavior constitute the salient features of this work. It is shown that early time falloff pressure data can be analyzed by non-Newtonian techniques while the late shut-in data, under certain conditions, can be analyzed by the conventional Horner method. The time when the Newtonian fluid starts influencing the non-Newtonian falloff curves and the location of the non-Newtonian fluid front can be estimated by using the radius of investigation equation for power-law fluids and volumetric balance equation respectively. Rheological consideration is made to illustrate the pressure transient behavior.

  18. 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

  19. Randomized Controlled Trial of Restrictive Fluid Management in Transient Tachypnea of the Newborn

    PubMed Central

    Stroustrup, Annemarie; Trasande, Leonardo; Holzman, Ian R.

    2011-01-01

    Objective To determine the effect of mild fluid restriction on the hospital course of neonates with transient tachypnea of the newborn (TTN). Study design This is a pilot prospective randomized controlled trial of 64 late preterm and term neonates diagnosed with TTN at a single tertiary-care hospital in the United States. Patients were randomized to receive standard fluid management or mild fluid restriction. Primary outcome was duration of respiratory support. Secondary outcomes were duration of admission to the ICU, time to first enteral feed, and total and composite hospital charges. Results were analyzed by t-test, chi-square, Kaplan-Meier estimation and proportional hazards regression. Results Fluid restriction did not cause adverse events or unsafe dehydration. Fluid management strategy did not affect primary or secondary outcomes in the broad study population. Fluid restriction significantly reduced duration of respiratory support (p=0.008) and hospitalization costs (p=0.017) for neonates with severe TTN. Conclusions Mild fluid restriction appears safe in late preterm and term neonates with uncomplicated TTN. Fluid restriction may be of benefit in decreasing duration of respiratory support and hospitalization charges in term and late preterm neonates with uncomplicated severe TTN. PMID:21839467

  20. Thermoelectric Energy Harvesting from Transient Ambient Temperature Gradients

    NASA Astrophysics Data System (ADS)

    Moser, André; Erd, Metin; Kostic, Milos; Cobry, Keith; Kroener, Michael; Woias, Peter

    2012-06-01

    We examine a thermoelectric harvester that converts electrical energy from the naturally occurring temperature difference between ambient air and large thermal storage capacitors such as building walls or the soil. For maximum power output, the harvester design is implemented in two steps: source matching of the thermal and electrical interfaces to the energy source (system level) followed by load matching of the generator to these interfaces (subsystem level). Therefore, we measure thermal source properties such as the temperature difference, the air velocity, and the cutoff frequency in two application scenarios (road tunnel and office building). We extend a stationary model of the harvester into the time domain to account for transient behavior of the source. Based on the model and the source measurements, we perform the source and load matching. The resulting harvester consists of a pin fin heat sink with a thermal resistance of 6.2 K/W and a cutoff frequency 2.5 times greater than that of the source, a thermoelectric generator, and a DC/DC step-up converter starting at a total temperature difference of only Δ T = 1.2 K. In a final road tunnel field test, this optimized harvester converts 70 mJ of electrical energy per day without any direct solar irradiation. The energy provided by the harvester enables 415 data transmissions from a wireless sensor node per day.

  1. 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.

  2. Fluid transients in fluid-structure interaction - 1987; Proceedings of the Third Symposium, Boston, MA, Dec. 13-18, 1987

    NASA Astrophysics Data System (ADS)

    Dodge, F. T.; Moody, F. J.

    Papers are presented on a three-dimensional analysis of liquid oxygen sloshing in the Space Shuttle external tank, the flow-induced oscillations of a novel double-wing spring-mass system, added mass and damping coefficents for a hexagonal cylinder, and a new hydraulic pressure intensifier using an oil hammer. Other topics include junction losses in pulsating flow, a finite element analysis of a slender fluid-structure system, two-phase blowdown through a short tube, and check valve behavior under transient flow conditions. Also considered are forces in initially empty pipes subject to rapid filling, a modal analysis of vibrations in liquid-filled piping systems, efficient computation of the pipeline break problem, and fluid dynamics associated with ductile pipeline fracture.

  3. 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).

  4. Fluid shear stress induces calcium transients in osteoblasts through depolarization of osteoblastic membrane.

    PubMed

    Sun, Junqing; Liu, Xifang; Tong, Jie; Sun, Lijun; Xu, Hao; Shi, Liang; Zhang, Jianbao

    2014-12-18

    Intracellular calcium transient ([Ca(2+)]i transient) induced by fluid shear stress (FSS) plays an important role in osteoblastic mechanotransduction. Changes of membrane potential usually affect [Ca(2+)]i level. Here, we sought to determine whether there was a relationship between membrane potential and FSS-induced [Ca(2+)]i transient in osteoblasts. Fluorescent dyes DiBAC4(3) and fura-2AM were respectively used to detect membrane potential and [Ca(2+)]i. Our results showed that FSS firstly induced depolarization of membrane potential and then a transient rising of [Ca(2+)]i in osteoblasts. There was a same threshold for FSS to induce depolarization of membrane potential and [Ca(2+)]i transients. Replacing extracellular Na(+) with tetraethylammonium or blocking stretch-activated channels (SACs) with gadolinium both effectively inhibited FSS-induced membrane depolarization and [Ca(2+)]i transients. However, voltage-activated K(+) channel inhibitor, 4-Aminopyridine, did not affect these responses. Removing extracellular Ca(2+) or blocking of L-type voltage-sensitive Ca(2+) channels (L-VSCCs) with nifedipine inhibited FSS-induced [Ca(2+)]i transients in osteoblasts too. Quantifying membrane potential with patch clamp showed that the resting potential of osteoblasts was -43.3mV and the depolarization induced by FSS was about 44mV. Voltage clamp indicated that this depolarization was enough to activated L-VSCCs in osteoblasts. These results suggested a time line of Ca(2+) mobilization wherein FSS activated SACs to promote Na(+) entry to depolarize membrane that, in turn, activated L-VSCCs and Ca(2+) influx though L-VSCCs switched on [Ca(2+)]i response in osteoblasts.

  5. Joule heating induced transient temperature field and its effects on electroosmosis in a microcapillary packed with microspheres.

    PubMed

    Kang, Y; Yang, C; Huang, X

    2005-08-02

    The Joule heating induced transient temperature field and its effect on the electroosmotic flow in a capillary packed with microspheres is analyzed numerically using the control-volume-based finite difference method. The model incorporates the coupled momentum equation for the electroosmotic velocity, the energy equations for the Joule heating induced temperature distributions in both the packed column and the capillary wall, and the mass and electric current continuity equations. The temperature-dependent physical properties of the electrolyte solution are taken into consideration. The characteristics of the Joule heating induced transient development of temperature and electroosmotic flow fields are studied. Specifically, the simulation shows that the presence of Joule heating causes a noticeable axial temperature gradient in the thermal entrance region and elevates a significant temperature increment inside the microcapillary. The temperature changes in turn greatly affect the electroosmotic velocity by means of the temperature-dependent fluid viscosity, dielectric constant, and local electric field strength. Furthermore, the model predicts an induced pressure gradient to counterbalance the axial variation of the electroosmotic velocity so as to maintain the fluid mass continuity. In addition, under specific conditions, the present model is validated by comparing with the existing analytical model and experimental data from the literature.

  6. Transient osmotic absorption of fluid in microvessels exposed to low concentrations of dimethyl sulfoxide.

    PubMed

    Glass, Catherine A; Perrin, Rachel M; Pocock, Tristan M; Bates, David O

    2006-01-01

    Dimethyl Sulfoxide (DMSO) is a common solvent for pharmacological agents. It is a small, lipophilic molecule thought to be relatively highly permeable through the cell membrane. While measuring the effect of low concentrations of DMSO (0.05-0.5% v/v) on capillary hydraulic conductivity as a vehicle control for pharmacological agents, the authors noticed what appeared to be an unusual transient absorption of fluid across the vessel wall. This absorption occurred during occlusion of the vessel, but dissipated quickly (1.7-8.6 s). The transient reabsorption reappeared upon each successive occlusion. To determine the nature of this transient absorption, the authors have measured the effect of increasing the pressure of the perfusing solution, of the concentration and time of perfusion of DMSO, and of superfusing the DMSO. They found that the absorption rate, but not the filtration rate, was concentration dependent, and was significantly correlated with the osmotic pressure of the DMSO. Moreover, the time taken for completion of the transient, i.e., time to reversal of flow, was inversely proportional to the hydraulic conductivity of the vessel. Furthermore, the transient absorption could be reduced and eventually abolished by increasing the hydrostatic pressure. These results strongly suggested that perfusion with low concentrations of DMSO could set up a significant osmotic pressure gradient across the vessel wall. This proposed mechanism for the absorption was confirmed by the measurement of a significant osmotic reflection coefficient of the vessel wall to DMSO (0.11 +/- 0.01). Relatively low concentrations (0.05-0.5%) of DMSO were therefore able to stimulate a significant osmotic transient across the blood vessel walls.

  7. Quantifying the residence time distribution of surface transient storage in streams: A computational fluid dynamics approach

    NASA Astrophysics Data System (ADS)

    Jackson, T. R.; Drost, K. J.; Haggerty, R.; Apte, S. V.

    2011-12-01

    Transient storage is the sum of surface transient storage (STS) and hyporheic transient storage (HTS) and separating the two storage components is challenging. A number of studies have attempted to determine the relationship between transient storage and stream channel properties; however, difficulties ensue when attempting to calculate STS. The present study attempts to develop a predictive relationship between a stream's STS residence time distribution (RTD) to physically-based and field-measureable properties of natural streams. Our approach is to use field measurements to constrain a computational fluid dynamics (CFD) model of STS and use both to develop and test a predictive model of STS RTD. Field sites were located on Oak and Soap creeks in the Willamette Valley near Corvallis, Oregon. Data collection included: (1) obtaining detailed stream and STS zone morphologies through dense survey measurements; (2) determining turbulence parameters and CFD model boundary inputs from stream and storage zone velocity measurements with a Marsh-McBirney and acoustic Doppler velocimeter; (3) quantifying the RTD and its mean using salt tracer injections and electrical conductivity probes; and (4) estimating mixing layer parameters using velocity measurements and a visual dye. Preliminary results from the CFD model and comparison to field data will be presented, and resulting insights into the RTD.

  8. 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.

  9. 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.

  10. Description of a high temperature downhole fluid sampler

    SciTech Connect

    Solbau, R.; Weres, O.; Hansen, L.; Dudak, B.

    1986-05-01

    Downhole fluid samplers have been used for years with limited success in high temperature geothermal wells. This paper discusses the development and operating principles of a high temperature downhole fluid sampler, reliable at obtaining samples at temperatures of up to 350/sup 0/C. The sampler was used successfully for recovering a brine sample from a depth of 10,200 ft in the Salton Sea Scientific Drilling Project well.

  11. Fluid transients in pipes. Reduction and control of pressure surges in liquids

    NASA Astrophysics Data System (ADS)

    1984-11-01

    ESDU 84013 provides a simplified graphical method for predicting maximum pressure changes in liquid filled pipework systems that may be treated as one-line systems. The method applies to pressures induced by partial or total valve closure, covering all common valve types, or pump trips. Data are also given for the estimation of the size of air vessel, situated just downstream of a pump, to protect against excessive upsurge and downsurge pressure changes following pump trip. A computer program is included to analyze transients in one-line systems and does not use the simplifying assumptions necessary for the graphical data. Practical worked examples, illustrating the use of the methods, are included and guidance is given on the data required for a full fluid transients analysis going beyond the scope of ESDU 84013.

  12. MINET: transient analysis of fluid-flow and heat-transfer networks

    SciTech Connect

    Van Tuyle, G.J.; Guppy, J.G.; Nepsee, T.C.

    1983-01-01

    MINET, a computer code developed for the steady-state and transient analysis of fluid-flow and heat-transfer networks, is described. The code is based on a momentum integral network method, which offers significant computational advantages in the analysis of large systems, such as the balance of plant in a power-generating facility. An application is discussed in which MINET is coupled to the Super System Code (SSC), an advanced generic code for the transient analysis of loop- or pool-type LMFBR systems. In this application, the ability of the Clinch River Breeder Reactor Plant to operate in a natural circulation mode following an assumed loss of all electric power, was assessed. Results from the MINET portion of the calculations are compared against those generated independently by the Clinch River Project, using the DEMO code.

  13. 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 %.

  14. 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.

  15. Transient deafness due to temperature-sensitive auditory neuropathy.

    PubMed

    Starr, A; Sininger, Y; Winter, M; Derebery, M J; Oba, S; Michalewski, H J

    1998-06-01

    To define mechanisms accounting for transient deafness in three children (two siblings, ages 3 and 6, and an unrelated child, age 15) when they become febrile. Audiometric tests (pure-tone audiometry, speech and sentence comprehension), tympanometry, middle ear muscle reflex thresholds, otoacoustic emissions (OAEs), and electrophysiological methods (auditory brain stem responses [ABRs], sensory evoked potentials, peripheral nerve conduction velocities) were used to test the children when they were afebrile and febrile. ABRs, when afebrile, were abnormal with a profound delay of the IV-V and absence of waves I-III. The ABR in one of the children, tested when febrile, showed no ABR components. Measures of cochlear receptor function using OAEs were normal in both febrile and afebrile states. Cochlear microphonic potentials were present in the three children, and a summating potential was likely present in two. When afebrile, there was a mild threshold elevation for all frequencies in the 15-yr-old and a mild elevation of thresholds for just low frequencies in the two siblings. Speech comprehension in quiet was normal but impaired in noise. One of the siblings tested when febrile had a profound elevation (>80 dB) of pure-tone thresholds and speech comprehension was absent. Acoustic reflexes subserving middle ear muscles and olivocochlear bundle were absent when febrile and when afebrile. No other peripheral or cranial nerve abnormalities were found in any of the children. Sensory nerve action potentials from median nerve in one of the children showed no abnormalities on warming of the hand to 39 degrees C. These children have an auditory neuropathy manifested by a disorder of auditory nerve function in the presence of normal cochlear outer hair cell functions. They develop a conduction block of the auditory nerves when their core body temperature rises due, most likely, to a demyelinating disorder of the auditory nerve. The auditory neuropathy in the two affected

  16. 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.

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

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Anderson, William G.

    2004-01-01

    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 in necessary. Many of the fluids considered are promising candidates as heat pipe fluids. Water is promising as a heat pipe fluid up to 500-550 K. Life test data for thermo-chemical compatibility are almost non-existent.

  18. 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.

  19. Effects of irrigation fluid temperature on core body temperature during transurethral resection of the prostate.

    PubMed

    Jaffe, J S; McCullough, T C; Harkaway, R C; Ginsberg, P C

    2001-06-01

    To determine the effect irrigation fluid temperature has on core body temperature changes in patients undergoing transurethral resection of the prostate (TURP). Fifty-six male patients (mean age 71.2 +/- 8.2 years) scheduled for TURP were enrolled in the study. Patients were randomized to one of two groups. Group 1 consisted of 27 patients who received room temperature irrigation fluid (70 degrees F) throughout TURP; group 2 consisted of 29 patients whose procedure was performed with warmed irrigation fluid (91.5 degrees F). The irrigation fluid used for both groups was glycine. The baseline temperature, final temperature, total time in the operating room, and amount of irrigation fluid used during the procedure were recorded for each patient. No significant difference in the average time spent in the operating room or in the total irrigation fluid used between the two groups was observed. Of the 27 patients who received room temperature irrigation fluid, 15 (55.6%) had a decrease in body temperature. A decrease in temperature was observed in 21 (72.4%) of the 29 patients who received warm irrigation fluid. Groups 1 and 2 had 12 (44.4%) of 27 and 8 (27.6%) of 29 patients, respectively, who demonstrated an elevation in their core body temperature. The results of our study suggest that irrigation fluid temperature is not a factor responsible for altering the core body temperature in patients undergoing TURP.

  20. Transient forcing effects on mixing of two fluids for a stable stratification

    NASA Astrophysics Data System (ADS)

    Pool, María.; Dentz, Marco; Post, Vincent E. A.

    2016-09-01

    Mixing and dispersion in coastal aquifers are strongly influenced by periodic temporal flow fluctuations on multiple time scales ranging from days (tides), seasons (pumping and recharge) to glacial cycles (regression and transgressions). Transient forcing effects lead to a complex space and time-dependent flow response which induces enhanced spreading and mixing of dissolved substances. We study effective mixing and solute transport in temporally fluctuating one-dimensional flow for a stable stratification of two fluids of different density using detailed numerical simulation as well as accurate column experiments. We quantify the observed transport behaviors and interface evolution by a time-averaged model that is obtained from a two-scale expansion of the full transport problem, and derive explicit expressions for the center of mass and width of the mixing zone between the two fluids. We find that the magnitude of transient-driven mixing is mainly controlled by the hydraulic diffusivity, the period, and the initial interface location. At an initial time regime, mixing can be characterized by an effective dispersion coefficient and both the interface position and width evolve linearly in time. At larger times, the spatial variability of the flow velocity leads to a deceleration of the interface and a compression of its width, which is manifested by a subdiffusive evolution of its width as t1/2.

  1. 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).

  2. 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.

  3. Design and transient computational fluid dynamics study of a continuous axial flow ventricular assist device.

    PubMed

    Song, Xinwei; Untaroiu, Alexandrina; Wood, Houston G; Allaire, Paul E; Throckmorton, Amy L; Day, Steven W; Olsen, Donald B

    2004-01-01

    A ventricular assist device (VAD), which is a miniaturized axial flow pump from the point of view of mechanism, has been designed and studied in this report. It consists of an inducer, an impeller, and a diffuser. The main design objective of this VAD is to produce an axial pump with a streamlined, idealized, and nonobstructing blood flow path. The magnetic bearings are adapted so that the impeller is completely magnetically levitated. The VAD operates under transient conditions because of the spinning movement of the impeller and the pulsatile inlet flow rate. The design method, procedure, and iterations are presented. The VAD's performance under transient conditions is investigated by means of computational fluid dynamics (CFD). Two reference frames, rotational and stationary, are implemented in the CFD simulations. The inlet and outlet surfaces of the impeller, which are connected to the inducer and diffuser respectively, are allowed to rotate and slide during the calculation to simulate the realistic spinning motion of the impeller. The flow head curves are determined, and the variation of pressure distribution during a cardiac cycle (including systole and diastole) is given. The axial oscillation of impeller is also estimated for the magnetic bearing design. The transient CFD simulation, which requires more computer resources and calculation efforts than the steady simulation, provides a range rather than only a point for the VAD's performance. Because of pulsatile flow phenomena and virtual spinning movement of the impeller, the transient simulation, which is realistically correlated with the in vivo implant scenarios of a VAD, is essential to ensure an effective and reliable VAD design.

  4. Chemical evolution of a high-temperature fracturing fluid

    SciTech Connect

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

    1985-10-01

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

  5. Low-temperature heat capacity of magnetic fluids

    NASA Astrophysics Data System (ADS)

    Lebedev, A. V.

    2008-12-01

    This paper continues the previous investigation into a recently discovered phenomenon of magnetic fluid solidification at temperatures essentially exceeding the freezing point of the base fluid. Physically, this phenomenon is related to the fact that at decreasing temperatures the magnetic fluid loses fluidity (with its viscosity tending to infinity) at a temperature higher than the freezing point of the base fluid. The main factor determining the freezing point is the type of the surface-active substance covering the particles. A group of different surfactants is examined with the aim of finding the lowest possible solidification temperature. The best result is obtained for linoleic acid (-100°C). In order to gain a deeper insight into the mechanisms of fluid solidification, a series of thermophysical measurements has been done. Heat capacity measurements made for an isooctane-based magnetic fluid stabilized by oleic acid at a temperature ranging from -130°C to 0 did not reveal any noticeable heat capacity anomalies in the vicinity of the solidification temperature. This suggests that the solidification of the magnetic fluid proceeds without phase transition. The highest peak of the heat flux is observed at the freezing point of isooctane. The position of the maximum slightly changes with the concentration of magnetic particles. With an increase of the concentration the temperature of the heat flux maximum decreases. In the presence of free oleic acid in isooctane a low peak is observed at a temperature of about -15°C. The peak position is independent of the oleic acid concentration. Tables 1, Figs 7, Refs 1.

  6. 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.

  7. 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.

  8. 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.

  9. Drilling fluid temperatures in a magma - penetrating wellbore

    SciTech Connect

    Finger, J.T.

    1986-01-01

    This paper describes the numerical modeling of the drilling fluid temperatures in a deep well that penetrates a magma body. The basic assumptions for the model are listed, the importance of the fluid temperature is considered, and the effect of changing the model parameters is assessed. The stratigraphy and formation temperature profile assumed for this hypothetical well are similar to Long Valley, CA, where a relatively shallow magma body is believed to exist. A major result of this modeling is demonstration of the benefit of insulated drillpipe.

  10. Water/Cerium as a Proxy for Slab Fluid Temperature

    NASA Astrophysics Data System (ADS)

    Cooper, L. B.; Plank, T.; Manning, C. E.; Hauri, E.; Zimmer, M.; Kelley, K.

    2008-12-01

    Numerical models and laboratory experiments predict widely varying temperatures of fluid generation in subducting slabs beneath volcanic arcs, from <600° C to >900° C. Moreover, slab thermal structures are expected to vary regionally, due to variations in mantle temperature, slab coupling, slab age and convergence rate. In order to provide constraints for such predictions, we develop here H2O/Ce as a potential slab fluid thermometer. Unlike incompatible trace elements, where concentrations in the fluid are governed by source abundances and partition coefficients, Ce fluid concentrations will be governed by the strongly temperature-dependent solubility of allanite and monazite, common REE-phases in sediment and basalt lithologies [1-4]. At low temperatures (<600° C), fluids saturated in allanite or monazite will have very low abundances of REE (<10 ppm) and low solute contents (H2O >90 wt%). At high temperatures (>900° C) fluids or melts will have high abundances of REE (>100 ppm) and low H2O contents (<10 wt%). Thus H2O/Ce in fluids will decrease by several orders of magnitude as temperature decreases across this relevant range, from >10,000 to <1000. Such variation is in stark contrast to the very small H2O/Ce variations expected during mantle melting, and observed in oceanic basalts far from subduction zones (150-250 [5]). We have examined H2O/Ce variations in volcanoes from several arcs, using H2O measurements from least degassed, primarily olivine-hosted melt inclusions and REE measurements from the same inclusions or whole rocks. H2O/Ce varies dramatically from <400 at Irazu in Costa Rica [6] and Tuxtepec in Mexico [7] to ~20,000 at submarine Volcano A in Tonga [8]. H2O/Ce in the fluid component for each arc can be estimated from linear mixing of Nb/Ce- H2O/Ce, between mantle, arc and a fluid end-member with zero Nb/Ce. Arc fluid end-members decrease in H2O/Ce systematically from Tonga and the Marianas (>5,000) to the Aleutians and Central America (<5

  11. Syndrome of Headache Accompanied with Transient Neurologic Deficits and Cerebrospinal Fluid Lymphocytosis

    PubMed Central

    ÇOBAN, Arzu; SHUGAIV, Erkingül; TÜZÜN, Erdem

    2013-01-01

    The syndrome of headache accompanied with transient neurologic deficits and cerebrospinal fluid lymphocytosis (HaNDL), is a rare, benign and self limiting syndrome. In the 2nd Edition of the International Classification of Headache Disorders, HaNDL syndrome was defined in secondary headache group as “Headache attributed to non-vascular intracranial disorder”. The etiology of HaNDL is still unknown. In recent years, some authors have shown that ion channel autoimmunity might at least partially contribute to HaNDL pathogenesis. In this paper, the definition of HaNDL syndrome, clinical picture and epidemiology of HaNDL syndrome, etiopathogenesis, differential diagnosis and treatment will be reviewed with the recent literature.

  12. Identification of relaxation parameter of a physical model of vein from fluid transient experiment

    NASA Astrophysics Data System (ADS)

    Hromádka, David; Chlup, Hynek; Žitný, Rudolf

    2014-03-01

    This paper presents a new fluid transient inflation experiment applied on a physical model of vein (short latex tube, 5mm diameter). Aim of experiments is assessment of wall viscous behaviour from attenuated pulsation of the tested sample. Experimental data obtained from dynamic test are compared with numerical simulation and a viscoelastic parameter of Haslach constitutive model is identified. It is verified that the viscoelasticity of wall has a greater impact to the damping of pulsation than the viscosity of water filling the sample and the attached capillary. Volume of sample depends on internal pressure measured by a pressure transducer. The maximum dissipation constitutive model of viscoelastic wall sample was employed for description of viscoelastic behaviour. Frequency of natural oscillation of pressure is determined by inertia of water column within the tested sample and attached capillary and by the tested specimen stiffness. The pressure pulsations are initiated by a sudden pressure drop at water surface.

  13. 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.

  14. 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.

  15. 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.

  16. A review of progress towards understanding the transient global mean surface temperature response to radiative perturbation

    NASA Astrophysics Data System (ADS)

    Yoshimori, Masakazu; Watanabe, Masahiro; Shiogama, Hideo; Oka, Akira; Abe-Ouchi, Ayako; Ohgaito, Rumi; Kamae, Youichi

    2016-12-01

    The correct understanding of the transient response to external radiative perturbation is important for the interpretation of observed climate change, the prediction of near-future climate change, and committed warming under climate stabilization scenarios, as well as the estimation of equilibrium climate sensitivity based on observation data. It has been known for some time that the radiative damping rate per unit of global mean surface temperature increase varies with time, and this inconstancy affects the transient response. Knowledge of the equilibrium response alone is insufficient, but understanding the transient response of the global mean surface temperature has made rapid progress. The recent progress accompanies the relatively new concept of the efficacies of ocean heat uptake and forcing. The ocean heat uptake efficacy associates the temperature response induced by ocean heat uptake with equilibrium temperature response, and the efficacy of forcing compares the temperature response caused by non-CO2 forcing with that by CO2 forcing.

  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. 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).

  19. Syndrome of transient headache and neurologic deficits with cerebrospinal fluid lymphocytosis (HaNDL): a pediatric case report.

    PubMed

    Gonçalves, Daniel; Meireles, Joana; Rocha, Ruben; Sampaio, Mafalda; Leão, Miguel

    2013-12-01

    The syndrome of transient headache and neurologic deficits associated with cerebrospinal fluid lymphocytosis (HaNDL) is characterized by 1 or more episodes of severe headache, transient neurologic deficits, and lymphocytic pleocytosis in the cerebrospinal fluid. It is a benign and self limited disorder seldom reported in pediatric age. We report the case of a 14-year-old girl who suffered from 2 episodes of headache with transient focal neurologic deficits and pleocytosis consistent with the syndrome of HaNDL. This entity should be taken into account as a differential diagnosis in otherwise healthy children presenting with recurrent headache and acute neurologic deficits. Repeated use of invasive and expensive laboratory and imaging investigations can be avoided when the diagnosis of the syndrome of HaNDL is correctly established.

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

    SciTech Connect

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

    1991-03-01

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

  1. Flowmeter measures flow rates of high temperature fluids

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1966-01-01

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

  2. 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.

  3. Simulation of intracellular [Formula: see text] transients in osteoblasts induced by fluid shear stress and its application.

    PubMed

    Sun, Junqing; Xie, Wenjun; Shi, Liang; Yu, Liyin; Zhang, Jianbao

    2017-04-01

    Intracellular [Formula: see text] transient induced by fluid shear stress (FSS) plays an important role in mechanical regulation of osteoblasts, but the cellular mechanism remains incompletely understood. Here, we constructed a mathematical model combined with experiments to elucidate it. Our simulated and experimental results showed that it was the delay of membrane potential repolarization to produce the refractory period of FSS-induced intracellular calcium transients in osteoblasts. Moreover, the results also demonstrated that the amplitude of FSS-induced intracellular calcium transient is crucial to the proliferation, while its duration is critical to the differentiation, of osteoblasts. Overall, the present study provides a way to understand the cellular mechanism of intracellular calcium transients in osteoblast induced by FSS and explains some of related physiological events.

  4. Transient thermal-mechanical behavior of cracked glass-cloth-reinforced epoxy laminates at low temperatures

    SciTech Connect

    Shindo, Y.; Ueda, S.

    1997-06-01

    We consider the transient thermal-mechanical response of cracked G-10CR glass-cloth-reinforced epoxy laminates with temperature-dependent properties. The glass-cloth-reinforced epoxy laminates are suddenly cooled on the surfaces. A generalized plane strain finite element model is used to study the influence of warp angle and crack formation on the thermal shock behavior of two-layer woven laminates at low temperatures. Numerical calculations are carried out, and the transient temperature distribution and the thermal-mechanical stresses are shown graphically.

  5. Application of the Taylor transformation to the transient temperature response of an annular fin

    SciTech Connect

    Yu, L.T.; Chen, C.K.

    1999-01-01

    This article presents the transient temperature response of a convective-radiative rectangular profile annular fin under a step temperature change occurring in its base. A convection-radiation fin tip is considered. The nonlinear transient heat transfer and boundary conditions are solved by using the hybrid method of Taylor transformation and finite-difference approximation. Also, time domain is controlled by Taylor transformation, and the spatial coordinates are handled by finite-difference approximation. Temperature distribution is implemented by employing natural cubic spline fitting.

  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. Transient emission wavelength estimation for DFB laser with temperature tuning

    NASA Astrophysics Data System (ADS)

    Li, Jin-yi; Qiao, Chen-zhi; Song, Li-mei; Guo, Qing-hua

    2017-03-01

    The prediction method of dynamic wavelength is proposed for temperature tuning process. The temperature of the thermistor integrated in laser diode (LD) module is recorded to predict the LD chip temperature. Then according to the injection current and priori tuning characteristics of the LDs, the emission wavelength is estimated in real time. The method is validated by using a 1.58 μm distributed feedback (DFB) LD. The absorption spectra of mixture gas of CO2 and CO are measured by means of the thermal tuning gas sensing system. The center wavelength of each absorption line is compared with the data in HITRAN2012 database. The results show that the deviations are less than 5 pm. This method fully meets the needs of spectroscopic measurement, and can be applied to spectroscopy, optical communications and other fields.

  8. A fluid-mechanics-based classification scheme for surface transient storage in riverine environments: quantitatively separating surface from hyporheic transient storage

    NASA Astrophysics Data System (ADS)

    Jackson, T. R.; Haggerty, R.; Apte, S. V.

    2013-04-01

    Surface transient storage (STS) and hyporheic transient storage (HTS) have functional significance in stream ecology and hydrology. Currently, tracer techniques couple STS and HTS effects on stream nutrient cycling; however, STS resides in localized areas of the surface stream and HTS resides in the hyporheic zone. These contrasting environments result in different storage and exchange mechanisms with the surface stream, which can yield contrasting results when comparing transient storage effects among morphologically diverse streams. We propose a fluid mechanics approach to quantitatively separate STS from HTS that involves classifying and studying different types of STS. As a starting point, a classification scheme is needed. This paper introduces a classification scheme that categorizes different STS in riverine systems based on their flow structure. Eight distinct STS types are identified and some are subcategorized based on characteristic mean flow structure: (1) lateral cavities (emerged and submerged); (2) protruding in-channel flow obstructions (backward- and forward-facing step); (3) isolated in-channel flow obstructions (emerged and submerged); (4) cascades and riffles; (5) aquatic vegetation (emerged and submerged); (6) pools (vertically submerged cavity, closed cavity, and recirculating reservoir); (7) meander bends; and (8) confluence of streams. The long-term goal is to use the classification scheme presented to develop predictive mean residence times for different STS using field-measureable hydromorphic parameters and obtain a theoretical STS residence time distribution (RTD). The STS RTD can then be deconvolved from the transient storage RTD (measured from a tracer test) to obtain an estimate of HTS.

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

    PubMed

    Morris, Nathan B; Bain, Anthony R; Cramer, Matthew N; Jay, Ollie

    2014-04-15

    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% Vo2peak 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% Vo2peak 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.

  10. 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

  11. BEM solution to transient free convective heat transfer in a viscous, electrically conducting, and heat generating fluid

    SciTech Connect

    Vajravelu, K.; Kassab, A.; Hadjinicolaou, A.

    1996-11-08

    The nonlinear partial differential equations for the transient free convective heat transfer in a viscous, electrically conducting, and heat-generating fluid past a vertical porous plate in the presence of free stream oscillations are solved by the boundary element method (BEM). Time-dependent fundamental solutions are employed in a time marching scheme to resolve the field variables. Numerical results are compared with previously reported analytical solutions in order to validate the developed BEM algorithm. These previous studies reported results for simpler versions of the problem, in which the convective effects in the momentum and energy equations were neglected in order to obtain analytical numerical solutions. The BEM results are shown to be in close agreement with the reported data. The effects of convection currents, the temperature-dependent heat sources (or sinks), the magnetic currents, and the viscous dissipation on the flow and heat transfer characteristics are assessed in a parametric study, which considers a variety of the dimensionless parameters Gr, Ec, Pr, M, and {gamma}. It is observed that {gamma} plays an important role in delaying the fluid flow reversal, present in the case of air, and acts to enhance the effect of Gr in augmenting the rate of heat transfer at the wall. The skin friction is observed to be an increasing function of Gr, Ec, and {gamma} and a decreasing function of M and Pr. However, the rate of heat transfer (in an absolute sense) is an increasing function of M, {gamma}, Gr, and Ec and a decreasing function of Pr. Of all the parameters, the Prandtl number has the strongest effect on the flow and heat transfer characteristics.

  12. THERMIT-2: a two-fluid model for light water reactor subchannel transient analysis. Final report

    SciTech Connect

    Kelly, J.E.; Kao, S.P.; Kazimi, M.S.

    1981-04-01

    The broad effort of developing and assessing the two fluid model computer code THERMIT for light water reactor (LWR) subchannel analysis is described. The developmental effort required a reformulation of the coolant-to-fuel rod coupling so that THERMIT is now capable of traditional coolant-centered subchannel analysis. A model that accounts for mass, momentum and energy transport between mesh cells due to turbulent mixing for two-phase conditions has also been introduced. This model is the first such attempt in a two-fluid context. The liquid-vapor interfacial exchange terms in the two-fluid model have been modified for improved accuracy. A systematic evaluation of the exchange models has been performed. The mass and momentum exchange rates between the vapor and the liquid for pre-CHF conditions were evaluated by comparison to void fraction data in over 30 one-dimensional steady-state experiments reported in the open literature. The liquid-vapor energy exchange rate for post-CHF conditions was assessed using 15 steady-state, one-dimensional wall temperature measurements. The mixing model was tested against G.E. and Ispra BWR and PWR rod-bundle measurements. Comparisons with these measurements have shown the appropriateness of this model.

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

    DOE PAGES

    Leishear, Robert A.; Gavalas, Nickolas A.

    2015-04-29

    High vacuum pressure measurements and calibrations below 1 × 10-8 Torr are problematic. Specifically, measurement accuracies change drastically for vacuum gauges when pressures are suddenly lowered in vacuum systems. How can gauges perform like this? A brief system description is first required to answer this question. Calibrations were performed using a vacuum calibration chamber with attached vacuum gauges. To control chamber pressures, vacuum pumps decreased the chamber pressure while nitrogen tanks increased the chamber pressure. By balancing these opposing pressures, equilibrium in the chamber was maintained at selected set point pressures to perform calibrations. When pressures were suddenly decreased duringmore » set point adjustments, a sudden rush of gas from the chamber also caused a surge of gas from the gauges to decrease the pressures in those gauges. Gauge pressures did not return to equilibrium as fast as chamber pressures due to the sparse distribution of gas molecules in the system. This disparity in the rate of pressure changes caused the pressures in different gauges to be different than expected. This discovery was experimentally proven to show that different gauge designs return to equilibrium at different rates, and that gauge accuracies vary for different gauge designs due to fluid transients in molecular flow.« less

  14. 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.

  15. Transient magnetic field and temperature modeling in large magnet applications

    SciTech Connect

    Gurol, H.; Hardy, G.E.; Peck, S.D.; Leung, E. . Space Systems Div.)

    1989-07-01

    This paper discusses a coupled magnetic/thermal model developed to study heat and magnetic field diffusion in conducting materials subject to time-varying external fields. There are numerous applications, both military and commercial. These include: energy storage devices, pulsed power transformers, and electromagnetic launchers. The time scales of interest may range from a magnetic field pulse of a microsecond in an electromagnetic launcher, to hundreds of seconds in an energy storage magnet. The problem can be dominated by either the magnetic field or heat diffusion, depending on the temperature and the material properties of the conductor. In general, heat diffuses much more rapidly in high electrical conductivity materials of cryogenic temperatures. The magnetic field takes longer to diffuse, since screening currents can be rapidly set up which shield the interior of the material from further magnetic field penetration. Conversely, in high resistivity materials, the magnetic field diffuses much more rapidly. A coupled two-dimensional thermal/magnetic model has been developed. The results of this model, showing the time and spatial variation of the magnetic field and temperature, are discussed for the projectile of an electromagnetic launcher.

  16. 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

  17. On monitoring and forecasting of graphite stack temperature in transient modes

    NASA Astrophysics Data System (ADS)

    Zagrebaev, A. M.; Ovsyannikova, N. V.; Ramazanov, R. N.

    2017-01-01

    The paper presents a method of monitoring and forecasting of the graphite stack temperature of the RBMK reactor in transient modes. The method is based on processing the in-core information about macro-distribution and mathematical model of distribution of temperature changes of the graphite stack in the reactor core. It is shown that the use of archival neutron field monitoring data allows determining the graphite stack temperature in the on-line mode.

  18. Thermocapillary motion of fluids in a temperature gradient

    NASA Astrophysics Data System (ADS)

    Gandhi, J. V.; Ignés-Mullol, Jordi; Bhagavatula, R.; Maher, J. V.

    1996-03-01

    footnotetext[1]Supported by the U.S. D.O.E. on grant #DE-FG02-84ER45131. We have studied the motion of a binary fluid mixture of water and Isobutyric acid (IBA) in a Hele-Shaw cell under the influence of a temperature gradient. A Hele-Shaw cell of inside dimensions 35mm x 31mm x 2mm was filled with a near-critical binary mixture of water and IBA with 40% IBA by volume. A uniform temperature gradient of 2.8 ^oC/cm was applied to the cell (along the 31mm side) with the highest temperature still below the coexistence temperature of the binary mixture. Phase migration occured such that water moved towards the colder end and the IBA-rich phase moved towards the hotter end of the cell. This effect is observed even against a small bouyancy force (bouyancy would have forced the less dense fluid IBA to stay at the colder end), and it is also observed in an off-critical sample where the interface moves in the direction which increases the interfacial tension. The phase migration is a slow process and may be related to the assymetry of the thermodynamic properties of the binary fluid system, as discussed by Ravi Bhagavatula^2. footnotetext[2]R. Bhagavatula, D. Jasnow, submitted to Journal of Chemical Physics.

  19. Equilibrium temperature in a clump of bacteria heated in fluid.

    PubMed Central

    Davey, K R

    1990-01-01

    A theoretical model was developed and used to estimate quantitatively the "worst case", i.e., the longest, time to reach equilibrium temperature in the center of a clump of bacteria heated in fluid. For clumps with 10 to 10(6) cells heated in vapor, such as dry and moist air, and liquid fluids such as purees and juices, predictions show that temperature equilibrium will occur with sterilization temperatures up to 130 degrees C in under 0.02 s. Model development highlighted that the controlling influence on time for heating up the clump is the surface convection thermal resistance and that the internal conduction resistance of the clump mass is negligible by comparison. The time for a clump to reach equilibrium sterilization temperature was therefore decreased with relative turbulence (velocity) of the heating fluid, such as occurs in many process operations. These results confirm widely held suppositions that the heat-up time of bacteria in vapor or liquid is not significant with usual sterilization times. PMID:2306095

  20. Effect of irrigation fluid temperature on core body temperature and inflammatory response during arthroscopic shoulder surgery.

    PubMed

    Pan, Xiaoyun; Ye, Luyou; Liu, Zhongtang; Wen, Hong; Hu, Yuezheng; Xu, Xinxian

    2015-08-01

    This study was designed to evaluate the influence of irrigation fluid on the patients' physiological response to arthroscopic shoulder surgery. Patients who were scheduled for arthroscopic shoulder surgery were prospectively included in this study. They were randomly assigned to receive warm arthroscopic irrigation fluid (Group W, n = 33) or room temperature irrigation fluid (Group RT, n = 33) intraoperatively. Core body temperature was measured at regular intervals. The proinflammatory cytokines TNF-α, IL-1, IL-6, and IL-10 were measured in drainage fluid and serum. The changes of core body temperatures in Group RT were similar with those in Group W within 15 min after induction of anesthesia, but the decreases in Group RT were significantly greater after then. The lowest temperature was 35.1 ± 0.4 °C in Group RT and 35.9 ± 0.3 °C in Group W, the difference was statistically different (P < 0.05). Hypothermia occurred in 31 out of 33 subjects in Group RT (31/33; 94 %), but was significantly lower in Group W (9/24; 27 %; P < 0.05). Serum TNF-α changes were undetectable postoperatively. No statistical significant differences in serum IL-1 and serum IL-10 levels were observed between groups. Serum IL-6 levels were significantly lower in Group W (P < 0.05). The levels of the above cytokines in drainage fluid were all significantly lower in Group W after surgery (P < 0.05). Hypothermia occurs more often in arthroscopic shoulder surgery by using room temperature irrigation fluid compared with warm irrigation fluid. And local inflammatory response is significantly reduced by using warm irrigation fluid. It seems that warm irrigation fluid is more recommendable for arthroscopic shoulder surgery.

  1. Imaging of Flame Temperature in a Combustion Chamber of Diesel Engine at Transient Operation

    NASA Astrophysics Data System (ADS)

    Kosaka, Hidenori; Sumi, Nariaki

    In this study, the flame temperature is visualized in a newly designed optical access diesel engine in order to investigate the mechanism of soot emission at transient operation mode. This single cylinder diesel engine has hydraulic variable valve system and an optical access window instead of an exhaust valve. Optical access window has cleaned by the laser cleaning technique in which the soot on the window is vaporized by the Nd:YAG laser incident. Using this optical engine, high speed photographs of flame were taken under transient operation, and flame temperature was analyzed by two color pyrometry.

  2. A Coupled Phase-Temperature Model for Dynamics of Transient Neuronal Signal in Mammals Cold Receptor.

    PubMed

    Kirana, Firman Ahmad; Alatas, Husin; Husein, Irzaman Sulaiman

    2016-01-01

    We propose a theoretical model consisting of coupled differential equation of membrane potential phase and temperature for describing the neuronal signal in mammals cold receptor. Based on the results from previous work by Roper et al., we modified a nonstochastic phase model for cold receptor neuronal signaling dynamics in mammals. We introduce a new set of temperature adjusted functional parameters which allow saturation characteristic at high and low steady temperatures. The modified model also accommodates the transient neuronal signaling process from high to low temperature by introducing a nonlinear differential equation for the "effective temperature" changes which is coupled to the phase differential equation. This simple model can be considered as a candidate for describing qualitatively the physical mechanism of the corresponding transient process.

  3. 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.

  4. 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.

  5. Syndrome of transient headache and neurologic deficits with cerebrospinal fluid lymphocytosis masquerading as meningitis in HIV patient

    PubMed Central

    Al Hadidi, Moayad; Meng, William D.; Jumean, Khalid

    2017-01-01

    Syndrome of transient headache and neurologic deficits with cerebrospinal fluid lymphocytosis (HaNDL syndrome) is described as “headache attributed to noninfectious inflammatory disease” featuring, as its name suggests, headache that mimics migraine in addition to neurologic symptoms such as hemiparesis, hemiparesthesia and dysphagia. We report a case of a 50-year-old African-American female who presented with headache, malaise and subsequent hemiparesis. Despite bearing a close resemblance to an acute episode of meningitis clinically, cerebrospinal fluid (CSF) analysis of the patient was only positive for isolated elevation in white cell count. The patient was diagnosed with HaNDL syndrome which is characterized by transient headache and neurologic deficits with CSF lymphocytosis. While the overall condition often appears substantial, the disease is self-limiting and patients usually recover spontaneously. PMID:28462218

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  7. Tile Lazor Code: Temperature Transients In Coated-Uncoated Cooled And Uncooled Laser Optics

    NASA Astrophysics Data System (ADS)

    Palmer, J. R.

    1988-06-01

    Lazar 'Lnc. has recently put on the market a new set of desk top Codes suitable for the Macintosh Plusnt that will allow the optical designer, systems analyst, or anyone that may be interested in the temperature transient when a reflective optical element is subjected to either continuous wave or repetitive pulsed laser radiation.

  8. A Coupled Phase-Temperature Model for Dynamics of Transient Neuronal Signal in Mammals Cold Receptor

    PubMed Central

    Kirana, Firman Ahmad; Husein, Irzaman Sulaiman

    2016-01-01

    We propose a theoretical model consisting of coupled differential equation of membrane potential phase and temperature for describing the neuronal signal in mammals cold receptor. Based on the results from previous work by Roper et al., we modified a nonstochastic phase model for cold receptor neuronal signaling dynamics in mammals. We introduce a new set of temperature adjusted functional parameters which allow saturation characteristic at high and low steady temperatures. The modified model also accommodates the transient neuronal signaling process from high to low temperature by introducing a nonlinear differential equation for the “effective temperature” changes which is coupled to the phase differential equation. This simple model can be considered as a candidate for describing qualitatively the physical mechanism of the corresponding transient process. PMID:27774102

  9. 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.

  10. Mechanical transients of single toad stomach smooth muscle cells. Effects of lowering temperature and extracellular calcium

    PubMed Central

    1990-01-01

    Smooth muscle's slow, economical contractions may relate to the kinetics of the crossbridge cycle. We characterized the crossbridge cycle in smooth muscle by studying tension recovery in response to a small, rapid length change (i.e., tension transients) in single smooth muscle cells from the toad stomach (Bufo marinus). To confirm that these tension transients reflect crossbridge kinetics, we examined the effect of lowering cell temperature on the tension transient time course. Once this was confirmed, cells were exposed to low extracellular calcium [( Ca2+]o) to determine whether modulation of the cell's shortening velocity by changes in [Ca2+]o reflected the calcium sensitivity of one or more steps in the crossbridge cycle. Single smooth muscle cells were tied between an ultrasensitive force transducer and length displacement device after equilibration in temperature-controlled physiological saline having either a low (0.18 mM) or normal (1.8 mM) calcium concentration. At the peak of isometric force, after electrical stimulation, small, rapid (less than or equal to 1.8% cell length in 3.6 ms) step stretches and releases were imposed. At room temperature (20 degrees C) in normal [Ca2+]o, tension recovery after the length step was described by the sum of two exponentials with rates of 40-90 s-1 for the fast phase and 2-4 s-1 for the slow phase. In normal [Ca2+]o but at low temperature (10 degrees C), the fast tension recovery phase slowed (apparent Q10 = 1.9) for both stretches and releases whereas the slow tension recovery phase for a release was only moderately affected (apparent Q10 = 1.4) while unaffected for a stretch. Dynamic stiffness was determined throughout the time course of the tension transient to help correlate the tension transient phases with specific step(s) in the crossbridge cycle. The dissociation of tension and stiffness, during the fast tension recovery phase after a release, was interpreted as evidence that this recovery phase resulted from

  11. Swelling and gas release in oxide fuels during fast temperature transients

    NASA Astrophysics Data System (ADS)

    Dollins, C. C.; Jursich, M.

    1982-05-01

    A previously reported intergranular swelling and gas release model for oxide fuels has been modified to predict fission gas behavior during fast temperature transients. Under steady state or slowly varying conditions it has been assumed in the previous model that the pressure caused by the fission gas within the gas bubbles is in equilibrium with the surface tension of the bubbles. During a fast transient, however, net vacancy migration to the bubbles may be insufficient to maintain this equilibrium. In order to ascertain the net vacancy flow, it is necessary to model the point defect behavior in the fuel. Knowing the net flow of vacancies to the bubble and the bubble size, the bubble diffusivity can be determined and the long range migration of the gas out of the fuel can be calculated. The model has also been modified to allow release of all the gas on the grain boundaries during a fast temperature transient. The gas release predicted by the revised model shows good agreement to fast transient gas release data from an EBR-II TREAT H-3 (Transient Reactor Test Facility) test. Agreement has also been obtained between predictions using the model and gas release data obtained by Argonne National Laboratory from out-of-reactor transient heating experiments on irradiated UO 2. It was found necessary to increase the gas bubble diffusivity used in the model by a factor of thirty during the transient to provide agreement between calculations and measurements. Other workers have also found that such an increase is necessary for agreement and attribute the increased diffusivity to yielding at the bubble surface due to the increased pressure.

  12. A fluid-mechanics based classification scheme for surface transient storage in riverine environments: quantitatively separating surface from hyporheic transient storage

    NASA Astrophysics Data System (ADS)

    Jackson, T. R.; Haggerty, R.; Apte, S. V.

    2013-07-01

    Surface transient storage (STS) and hyporheic transient storage (HTS) have functional significance in stream ecology and hydrology. Currently, tracer techniques couple STS and HTS effects on stream nutrient cycling; however, STS resides in localized areas of the surface stream and HTS resides in the hyporheic zone. These contrasting environments result in different storage and exchange mechanisms with the surface stream, which can yield contrasting results when comparing transient storage effects among morphologically diverse streams. We propose a fluid mechanics approach to quantitatively separate STS from HTS that involves classifying and studying different types of STS. As a starting point, a classification scheme is needed. This paper introduces a classification scheme that categorizes different STS in riverine systems based on their flow structure. Eight STS types are identified and some are subcategorized based on characteristic mean flow structure: (1) lateral cavities (emergent and submerged); (2) protruding in-channel flow obstructions (backward- and forward-facing step); (3) isolated in-channel flow obstructions (emergent and submerged); (4) cascades and riffles; (5) aquatic vegetation (emergent and submerged); (6) pools (vertically submerged cavity, closed cavity, and recirculating reservoir); (7) meander bends; and (8) confluence of streams. The long-term goal is to use the classification scheme presented to develop predictive mean residence times for different STS using field-measurable hydromorphic parameters and obtain an effective STS mean residence time. The effective STS mean residence time can then be deconvolved from the transient storage residence time distribution (measured from a tracer test) to obtain an estimate of HTS mean residence time.

  13. Deflagration-induced pressure and temperature transients in a waste storage facility

    SciTech Connect

    Ades, M.J.; Polizzi, L.M.

    1995-12-31

    This paper presents a study for a facility where a deflagration of flammable vapors takes place, and the generated pressure and temperature transients are analyzed to evaluate the pressure differentials induced on the various components of the facility to assesses their structural integrity. The temperature profiles are also analyzed to assess the qualification of the equipment that is required to operate during and after such an accident.

  14. 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.

  15. 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.

  16. Cu and Ni solubility in high-temperature aqueous fluids

    NASA Astrophysics Data System (ADS)

    Watenphul, A.; Scholten, L.; Beermann, O.; Kavner, A.; Alraun, P.; Falkenberg, G.; Newville, M.; Lanzirotti, A.; Schmidt, C.

    2013-12-01

    Copper and nickel are generally associated in magmatic sulfide ores formed by immiscibility in mafic and ultramafic magmas. In contrast, hydrothermal Cu-Ni deposits are uncommon and these elements usually occur in separate Cu-Fe-sulfide and Ni-Co-Ag-Bi-As-S mineralizations. Among the porphyry-type deposits formed at high temperatures to about 700 °C, there are many copper but no nickel deposits [1], pointing to a higher solubility of Cu relative to Ni in aqueous fluids at such conditions. The aim of this study is to measure the solubilities of Cu and Ni sulfides in high-temperature hydrothermal fluids in-situ using synchrotron-radiation micro-X-ray fluorescence spectrometry. Synthetic CuS or NiS crystals were partly dissolved in aqueous NaCl, NaCl+HCl, or CaCl2 solutions at temperatures of 400 to 600 °C and pressures between 70 and 900 MPa using a modified hydrothermal diamond-anvil cell with a recess in one diamond [2]. Consecutive XRF spectra of the fluid in the recess were collected in a confocal mode to exclude signal contributions from the crystals in the sample chamber [3]. Equilibrium was assumed if the determined concentrations of the dissolved metals indicated that a steady state was attained. The measured dissolved Cu concentrations ranged between 22 ppm at 70 MPa, 500 °C and 235 ppm at 306 MPa, 600 °C in 0.5 to 1.6 m NaCl solutions. We observed a decrease in Cu concentration with increasing pressure at constant temperature, and for 1.6 m NaCl an increase by a factor of two along an isochore from 120 MPa, 500 °C to 306 MPa, 600 °C. Higher Cu solubilities were determined in more concentrated solutions. A preliminary run with a more acidic NaCl+HCl solution (pH ~1) revealed a dramatic increase in the dissolved Cu concentration to 7898 ppm at 170 MPa, 500 °C. The measured dissolved Ni concentrations ranged between 3 ppm at 200 MPa, 500 °C in a 1 m NaCl solution and 33 ppm at 411 MPa, 500 °C in a 0.75 m CaCl2 solution. A solubility maximum at 500

  17. Numerical solutions of reactive fluid flows during postignition transients in hybrid rocket systems.

    NASA Technical Reports Server (NTRS)

    Hung, W. S. Y.; Chen, C. S.; Haviland, J. K.

    1972-01-01

    A computational method has been developed for the study of the post-ignition transients in hybrid rocket systems. The particular system chosen consisted of a gaseous oxidizer flowing within a tube of solid fuel, resulting in heterogeneous combustion. With the appropriate assumptions, two-dimensional, time-dependent conservation equations were derived for the reacting gas phase, and for the solid phase, in a cylindrical coordinate system. These were then programmed for numerical computation, using two implicit finite-difference schemes, the Lax-Wendroff scheme for the gas phase, and the Crank-Nicolson scheme for the solid phase. Appropriate initial and boundary conditions were represented, including heat and mass conservation at the interface between gas and solid. Initially, no attempt was made to relate the recession rate at the surface to the surface temperature, or to include heat transfer by radiation. A simple case was selected for preliminary calculations, with aluminum and oxygen as fuel and oxidizer, and aluminum oxide as the product.

  18. A 2-D basin-scale methane hydrate model: equilibrium and transient sensitivity to ocean temperature. (Invited)

    NASA Astrophysics Data System (ADS)

    Archer, D. E.; McGuire, P. C.; Buffett, B. A.

    2010-12-01

    Carbon and oxygen isotopic variations through the Paleocene-Eocene thermal maximum event suggest that biogenic methane was not the source of the perturbing carbon, but this does not guarantee that the hydrates on Earth today will not eventually respond to the unique provocation of the global warming climate event. The SpongeBOB ocean methane hydrate model is used to simulate the accumulation of sediment along a passive continental margin over geologic time scales. Fluid motions within the sediment column are driven by compaction and variations in sediment permeability, and they impact the efficiency of methane trapping within hydrate deposits. The equilibrium and transient sensitivity of the methane inventory in the sediments to the temperature of the ocean will be assessed.

  19. EDITORIAL: A Survey of Facilities for High-Temperature, High-Pressure Fluids Experiments

    NASA Astrophysics Data System (ADS)

    Argrow, Brian M.

    2005-09-01

    Similarity laws have opened the door for fluid dynamic experiments using subscale models. These laws enable the study of dynamically similar flows with geometrically similar models that are a fraction of the full-scale size with a concomitant reduction in required power. In some instances these similarity laws require experimental facilities that operate with fluids under very high temperatures and pressures in order to push the similarity variables to full-scale values or at least to useful values. High-enthalpy flow conditions encountered in hypersonic flight require testing facilities that produce chemically reacting flows and plasmas. Ignition processes and chemical kinetics generally require high temperature and pressure facilities. Shock tubes provide a reliable and repeatable means to produce conditions for high enthalpy flows and chemical kinetics. The short duration of any flow state in a shock tube, usually of the order of milliseconds, presents measurement challenges for fluid properties and reaction rates. Similarly, extremely fast response times are required to measure transient flow quantities in turbomachinery. The exploitation of material properties to create useful test conditions often introduces 'side effects' that must be accounted for in models and measurements. Paradoxically, the most difficult part of some experiments can be the understanding and management of these effects. For example, the thermodynamic state of a working fluid might be far from that encountered by a full-scale system, or the mechanical properties and dynamical behaviour of structural materials might determine the feasibility of meaningful measurements. For modelling and risk management, the behaviour of candidate materials and working fluids must be thoroughly understood. In this special feature, we survey some of the facilities and methods that have been developed for the measurement of fluid properties and processes under a wide range of conditions. Our focus is on

  20. 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.

  1. Synthetic Temperature-Depth Transients Based On Solar Forcing vs. Observed From Repeated Well Temperature Logs in the Canadian Prairies

    NASA Astrophysics Data System (ADS)

    Skinner, W.; Majorowicz, J. A.; Safanda, J.

    2009-12-01

    Temperature-logs in boreholes made initially two decades ago, and repeated a single decade ago, were recently repeated in 2006 and 2007. Modelling of the synthetic temperature-depth transients shows that repeated logs in the Canadian Prairies follow surface air temperature change forcing for the time interval between logs with surface temperature changes 0.2°C, and 0.4°C, for time spans of one and two decades, respectively. Composite top of the atmosphere (TOA) solar irradiance recorded by satellite since 1978 was scaled to the regional latitude/longitude position of the repeated logging experiment to provide a forcing signal to model subsurface temperatures, as previously done with SAT data. The feedback parameter used is assumed a priori as 3.0*COS(latitude in degrees) - 0.42) Wm-2/°C, which yields 0.71 - 0.59 for latitudes 49-52° and mean sensitivity 1.41 - 1.69 °C/Wm-2. While these sensitivity values correspond to equilibrium models in the transient times before the climate system reaches the equilibrium, the temperature change is smaller and likely closer to 1°C/Wm-2. Even for this higher mean sensitivity, the temperature response is not large enough to explain the ground surface temperature change. As surface air temperature forcing explains the observed sub-surface transients, factors other than solar forcing must be responsible for the observed large recent warming, likely anthropogenic changes related to the greenhouse effect.

  2. 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.

  3. Reconstruction of Past Ocean Salinity and Temperature from Pore Fluids

    NASA Astrophysics Data System (ADS)

    Miller, M. D.; Adkins, J. F.; Simons, M.; Minson, S. E.

    2012-12-01

    Ocean sediment pore fluid profiles of Cl- and δ18O can be used to reconstruct Last Glacial Maximum (LGM) ocean bottom temperatures and salinities (McDuff 1985,Schrag and DePaolo 1993, Schrag 1996, Paul et al. 2001, Adkins et al. 2002, Malone et al. 2004). Such reconstructions require use of a computational model of tracer transport and diffusion in sediments. Previous work inferred the boundary condition at the sediment-water interface by assuming its shape, for example that it scaled to the global mean sea level history. However, this approach assumes a simple relationship between local water properties and the global mean as well as a fixed spatial distribution of ocean water properties, relationships that are not supported by modern observations. Assuming the boundary condition shape scales to the local benthic δ18O history, another method previously used, requires constraints on the relationship between temperature, δ18O, and salinity. Further, as the evolution of concentrations in ocean sediment pore fluids is a diffusion-dominated problem, the solution to the inverse problem is not unique. It is difficult using previous methods to assign objective error bars to reconstructed temperatures and salinities. We seek to avoid the assumption that bottom water property histories scale to the sea level, and thus also avoid the assumption that there exists a simple relationship between bottom water properties at distantly spaced points in the ocean. We then seek to re-calculate previously reported bottom water salinities and temperatures and obtain robust error estimates on these values. To accomplish these goals, we consider two different approaches: linear regularization techniques and Bayesian Markov Chain Monte Carlo (MCMC) sampling. Using synthetic examples, we show that within the context of the necessary assumptions, linear regularization techniques can be informative, and that salinity and δ18O of bottom water at the LGM are robust features of the data

  4. Effects of transient temperature conditions on the divergence of activated sludge bacterial community structure and function.

    PubMed

    Nadarajah, Nalina; Allen, D Grant; Fulthorpe, Roberta R

    2007-06-01

    The effect of temperature fluctuations on bacterial community structure and function in lab-scale sequencing batch reactors treating bleached kraft mill effluent was investigated. An increase in temperature from 30 to 45 degrees C caused shifts in both bacterial community structure and function. Triplicate reactors were highly similar for 40 days following startup. After the temperature shift, their community structure and function started to diverge from each other and from the control. A multi-response permutation procedure confirmed that the variability in community structure between transient and control reactors were greater than that among the triplicate transient reactors. The fact that these disturbances manifest themselves in different ways in apparently identical reactors suggests a high degree of variability between replicate systems.

  5. 3D transient temperature measurement in homogeneous solid material with THz waves

    NASA Astrophysics Data System (ADS)

    Romano, M.; Sommier, A.; Batsale, J.-C.; Pradere, C.

    2016-04-01

    The first imaging system that is able to measure transient temperature phenomena taking place inside a bulk by 3D tomography is presented. This novel technique combines the power of terahertz waves and the high sensitivity of infrared imaging. The tomography reconstruction is achieved by the 3D motion of the sample at several angular positions followed by inverse Radon transform processing to retrieve the 3D transient temperatures. The aim of this novel volumetric imaging technique is to locate defects within the whole target body as well as to measure the temperature in the whole volume of the target. This new-fashioned thermal tomography will revolutionize the non-invasive monitoring techniques for volume inspection and in-situ properties estimations.

  6. 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.

  7. 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...

  8. 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...

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Transient Response of Arc Temperature and Iron Vapor Concentration Affected by Current Frequency with Iron Vapor in Pulsed Arc

    NASA Astrophysics Data System (ADS)

    Tanaka, Tatsuro; Maeda, Yoshifumi; Yamamoto, Shinji; Iwao, Toru

    2016-10-01

    TIG arc welding is chemically a joining technology with melting the metallic material and it can be high quality. However, this welding should not be used in high current to prevent cathode melting. Thus, the heat transfer is poor. Therefore, the deep penetration cannot be obtained and the weld defect sometimes occurs. The pulsed arc welding has been used for the improvement of this defect. The pulsed arc welding can control the heat flux to anode. The convention and driving force in the weld pool are caused by the arc. Therefore, it is important to grasp the distribution of arc temperature. The metal vapor generate from the anode in welding. In addition, the pulsed current increased or decreased periodically. Therefore, the arc is affected by such as a current value and current frequency, the current rate of increment and the metal vapor. In this paper, the transient response of arc temperature and the iron vapor concentration affected by the current frequency with iron vapor in pulsed arc was elucidated by the EMTF (ElectroMagnetic Thermal Fluid) simulation. As a result, the arc temperature and the iron vapor were transient response as the current frequency increase. Thus, the temperature and the electrical conductivity decreased. Therefore, the electrical field increased in order to maintain the current continuity. The current density and electromagnetic force increased at the axial center. In addition, the electronic flow component of the heat flux increased at the axial center because the current density increased. However, the heat conduction component of the heat flux decreased.

  14. Measurement of transient strain and surface temperature on simulated turbine blades using noncontacting techniques

    NASA Technical Reports Server (NTRS)

    Calfo, F. D.; Pollack, F. G.

    1978-01-01

    Noncontacting techniques were used to measure strain and temperature in thermally cycled simulated turbine blades. An electro-optical extensometer was used to measure the displacement between parallel targets mounted on the leading edge of the blades throughout a complete heating and cooling cycle. An infrared photographic pyrometry method was used to measure blade steady state surface temperature. The blade was cyclically heated and cooled by moving it into and out of a Mach 1 hot-gas stream. Transient leading edge strain and steady state surface temperature distributions are presented for blades of three different configurations.

  15. 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.

  16. Dating fluid flow in developing passive margins using low-temperature thermochronology

    NASA Astrophysics Data System (ADS)

    Gleadow, A. J.; Seiler, C.; Kohn, B. P.

    2012-12-01

    Despite the importance of fluid flow for mass flux and remobilisation in the Earth's crust, the age of past fluid flow events is often difficult to determine, particularly in the low-temperature environment of the shallow crust. This is partly because mineral phases precipitated by low-temperature fluids are either lacking or not very easy to date. Low-temperature thermochronometers such as apatite fission track (AFT) and (U-Th)/He (AHe) systems are, in theory, ideally suited to investigate the temperature interval of hydrothermal fluids near the Earth's surface and could be used to date fluid flow in the shallow crust. In passive margins, however, rift-related faulting, exhumation and post-breakup erosion often result in a much stronger regional cooling signal that relates to tectonic events rather than fluid flow. Moreover, the response of low-temperature thermochronometers to transient and potentially short-lived thermal events associated with hydrothermal fluids has not been studied systematically and is poorly known. In this study, we report AFT and AHe results from two young, regionally important faults that were active at different stages of passive margin evolution in the Gulf of California rift system. In the first case, we investigate the thermal history of the Libertad fault in central Baja California, which represents the breakaway fault for Late Miocene to recent rifting. Regional background AFT and AHe ages range between ~60-35Ma, they predate rifting and are likely associated with steady erosional unroofing of the basement. In contrast, a closely spaced 3D grid of samples from the Libertad escarpment records a distinct Late Miocene thermal event at ~9-8Ma that can be traced several kilometres along the base and a few hundred metres up the escarpment face. In the second case, we collected a 2D grid of samples orthogonal to the Ballenas transform, a transform fault located ~3-5km offshore the coast of central Baja California that is part of the current

  17. Transient receptor potential melastatin 8 (TRPM8) channels are involved in body temperature regulation.

    PubMed

    Gavva, Narender R; Davis, Carl; Lehto, Sonya G; Rao, Sara; Wang, Weiya; Zhu, Dawn X D

    2012-05-09

    Transient receptor potential cation channel subfamily M member 8 (TRPM8) is activated by cold temperature in vitro and has been demonstrated to act as a 'cold temperature sensor' in vivo. Although it is known that agonists of this 'cold temperature sensor', such as menthol and icilin, cause a transient increase in body temperature (Tb), it is not known if TRPM8 plays a role in Tb regulation. Since TRPM8 has been considered as a potential target for chronic pain therapeutics, we have investigated the role of TRPM8 in Tb regulation. We characterized five chemically distinct compounds (AMG0635, AMG2850, AMG8788, AMG9678, and Compound 496) as potent and selective antagonists of TRPM8 and tested their effects on Tb in rats and mice implanted with radiotelemetry probes. All five antagonists used in the study caused a transient decrease in Tb (maximum decrease of 0.98°C). Since thermoregulation is a homeostatic process that maintains Tb about 37°C, we further evaluated whether repeated administration of an antagonist attenuated the decrease in Tb. Indeed, repeated daily administration of AMG9678 for four consecutive days showed a reduction in the magnitude of the Tb decrease Day 2 onwards. The data reported here demonstrate that TRPM8 channels play a role in Tb regulation. Further, a reduction of magnitude in Tb decrease after repeated dosing of an antagonist suggests that TRPM8's role in Tb maintenance may not pose an issue for developing TRPM8 antagonists as therapeutics.

  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. Plume formation in strongly temperature-dependent viscosity fluids: Application to early Mars

    NASA Astrophysics Data System (ADS)

    Ke, Yun

    One of the most prominent features of Mars is the hemispherical dichotomy. The Martian surface consists of a heavily cratered elevated southern hemisphere and a resurfaced depressed northern hemisphere. The dichotomy seems to have formed very early in the history of the planet. Another interesting feature is a remnant magnetization of the crust, which suggests that early Mars had a magnetic field. Investigation of the origin of these features provides insights into the early history of Mars as well as other terrestrial planets including Earth. We develop a hypothesis that the dichotomy is caused by an early transient superplume produced by a hot Martian core. At first glance, the superplume hypothesis seems unlikely because the number of plumes in typical fluids heated from below is very large and the plumes are relatively small. However, solid rocks are rather unusual fluids whose viscosity varies with temperature by many orders of magnitude. Plume formation in such fluids is a complex and poorly understood phenomena. Thus, we begin with a systematic two- dimensional numerical and theoretical investigation of plume formation in strongly temperature-dependent viscosity fluids. Then we extend both the numerical calculations and the theory to fully three-dimensional geometry. We find the conditions under which a single transient superplume forms. One of the most important conditions is the requirement that the core was at least several hundred degrees Kelvin hotter than the mantle. Geophysical data and theoretical models of core formation suggest that this is likely to be the case. We find that the superplume can easily satisfy the timing constraints on the formation of the dichotomy. In the last part we consider the coupled core-mantle thermal evolution and investigate the cooling of the initially superheated core and the generation of the magnetic field on early Mars. We show that the core cooling is sufficiently rapid to induce convection inside the core and allow

  2. 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.

  3. One Crystal, Two Temperatures: Cryocooling Penalties Alter Ligand Binding to Transient Protein Sites

    DOE PAGES

    Fischer, Marcus; Shoichet, Brian K.; Fraser, James S.

    2015-05-28

    Interrogating fragment libraries by X-ray crystallography is a powerful strategy for discovering allosteric ligands for protein targets. Cryocooling of crystals should theoretically increase the fraction of occupied binding sites and decrease radiation damage. However, it might also perturb protein conformations that can be accessed at room temperature. Using data from crystals measured consecutively at room temperature and at cryogenic temperature, we found that transient binding sites could be abolished at the cryogenic temperatures employed by standard approaches. Finally, changing the temperature at which the crystallographic data was collected could provide a deliberate perturbation to the equilibrium of protein conformations andmore » help to visualize hidden sites with great potential to allosterically modulate protein function.« less

  4. One Crystal, Two Temperatures: Cryocooling Penalties Alter Ligand Binding to Transient Protein Sites

    SciTech Connect

    Fischer, Marcus; Shoichet, Brian K.; Fraser, James S.

    2015-05-28

    Interrogating fragment libraries by X-ray crystallography is a powerful strategy for discovering allosteric ligands for protein targets. Cryocooling of crystals should theoretically increase the fraction of occupied binding sites and decrease radiation damage. However, it might also perturb protein conformations that can be accessed at room temperature. Using data from crystals measured consecutively at room temperature and at cryogenic temperature, we found that transient binding sites could be abolished at the cryogenic temperatures employed by standard approaches. Finally, changing the temperature at which the crystallographic data was collected could provide a deliberate perturbation to the equilibrium of protein conformations and help to visualize hidden sites with great potential to allosterically modulate protein function.

  5. A theoretical model of accelerated irradiation creep at low temperatures by transient interstitial absorption

    SciTech Connect

    Stoller, R.E.; Grossbeck, M.L.; Mansur, L.K.

    1990-01-01

    A theoretical model has been developed using the reaction rate theory of radiation effects to explain experimental results that showed higher than expected values of irradiation creep at low temperatures in the Oak Ridge Research Reactor. The customary assumption that the point defect concentrations are at steady state was not made; rather, the time dependence of the vacancy and interstitial concentrations and the creep rate were explicitly calculated. For temperatures below about 100 to 200{degree}C, the time required for the vacancy concentration to reach steady state exceeds the duration of the experiment. For example, if materials parameters typical of austenitic stainless steel are used, the calculated vacancy transient dose at 100{degree}C is about 100 dpa. At 550{degree}C this transient is over by 10{sup {minus}8} dpa. During the time that the vacancy population remains lower than its steady state value, dislocation climb is increased since defects of primarily one type are being absorbed. Using the time-dependent point defect concentrations, the dislocation climb velocity has been calculated as a function of time and a climb-enabled glide creep model had been invoked. The extended transient time for the vacancies leads to high creep rates at low temperatures. In agreement with the experimental observations, a minimum in the temperature dependence of creep is predicted at a temperature between 50 and 350{degree}C. The temperature at which the minimum occurs decreases as the irradiation dose increases. Predicted values of creep at 8 dpa are in good agreement with the results of the ORR-MFE-6J/7J experiment.

  6. Fluid transients in fluid-structure interaction - 1985; Proceedings of the second symposium, Miami Beach, FL, November 17-22, 1985

    SciTech Connect

    Dodge, F.T.; Moody, F.J.

    1985-01-01

    Topics discussed include the dynamics of liquid sloshing in upright and inverted bladdered tanks, velocity profiles in decelerating turbulent pipe flows, fluid-dynamic aspects of torsional aeroelasticity in steam turbine low-pressure bladings, and the effect of encroachments on structure impact loads during a pool swell transient based on small-scale testing. Consideration is also given to shock wave effects on shut-off-rod guide tubes, the response of an immersed elastic tube bundle to pressure transient, problems encountered in modeling water vapor column separation, and the mechanism of pressure oscillation due to steam condensation in water. Papers are presented on the impact pressure from the sudden arrival of gas/liquid mixtures at a relief valve discharging gas, a multidimensional waterhammer analysis using a node-flow link approach, Poisson's ratio effects on the celerity of a pressure surge in rectangular section pipes and conduits, and analysis and computer simulation for transient flow in a complex system of liquid piping.

  7. Improved analysis of transient temperature data from permanent down-hole gauges (PDGs)

    NASA Astrophysics Data System (ADS)

    Zhang, Yiqun; Zheng, Shiyi; Wang, Qi

    2017-08-01

    With the installation of permanent down-hole gauges (PDGs) during oil field development, large volumes of high resolution and continuous down-hole information are obtainable. The interpretation of these real-time temperature and pressure data can optimize well performance, provide information about the reservoir and continuously calibrate the reservoir model. Although the dynamic temperature data have been interpreted in practice to predict flow profiling and provide characteristic information of the reservoir, almost all of the approaches rely on established non-isothermal models which depend on thermodynamic parameters. Another problem comes from the temperature transient analysis (TTA), which is underutilized compared with pressure transient analysis (PTA). In this study, several model-independent methods of TTA were performed. The entire set of PDG data consists of many flow events. By utilizing the wavelet transform, the exact points of flow-rate changes can be located. The flow regime changes, for example, from early time linear flow to later time pseudo-radial flow, among every transient period with constant flow-rate. For the early time region (ETR) that is caused by flow-rate change operations, the TTA, along with the PTA can greatly reduce the uncertainties in flow regime diagnosis. Then, the temperature variations during ETR were examined to infer the true reservoir temperature history, and the relationships between the wavelet detailed coefficients and the flow-rate changes were analysed. For the scenarios with constant reservoir-well parameters, the detailed flow-rate history can be generated by calculating the coefficient of relationship in advance. For later times, the flow regime changes to pseudo-radial flow. An analytical solution was introduced to describe the sand-face temperature. The formation parameters, such as permeability and skin factor, were estimated with the previously calculated flow-rate. It is necessary to analyse temperature

  8. Thermostat for high temperature and transient characterization of thin film thermoelectric materials.

    PubMed

    Singh, Rajeev; Shakouri, Ali

    2009-02-01

    We have designed and fabricated a vacuum-insulated thermostat capable of measuring the thermoelectric properties of thin films from room temperature to 850 K. High speed Seebeck voltage transients are resolved to 200 ns with 63 dB dynamic range in order to directly measure thermoelectric device figure of merit. In-plane Seebeck coefficient probes measure voltage and temperature difference at identical locations with low parasitic contributions. In-plane electrical conductivity measurement is accomplished at high speed to avoid possible Seebeck voltage effect on van der Pauw measurements.

  9. Extension of Lithium Ion Cell Model to Include Transient and Low-Temperature Behaviour

    NASA Astrophysics Data System (ADS)

    Dudley, G.

    2014-08-01

    Current-interruption resistance measurements have been analysed in detail allowing the ESTEC lithium ion cell electrical/thermal model to be extended to allow modelling of cell voltage in response to imposed current changes at low temperatures and short time scales where activation polarisation becomes important. Whilst an unnecessary complication in most cases, this extension is needed under certain circumstances such as the simulation of Mars rover batteries forced to operate at low temperature and possible effects of battery voltage transients on battery-bus power subsystems. Comparison with test data show that the model is capable of giving a good fit in these circumstances.

  10. 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.

  11. Investigation of transient temperature's influence on damage of high-speed sliding electrical contact rail surface

    NASA Astrophysics Data System (ADS)

    Zhang, Yuyan; Sun, Shasha; Guo, Quanli; Yang, Degong; Sun, Dongtao

    2016-11-01

    In the high speed sliding electrical contact with large current, the temperature of contact area rises quickly under the coupling action of the friction heating, the Joule heating and electric arc heating. The rising temperature seriously affects the conductivity of the components and the yield strength of materials, as well affects the contact state and lead to damage, so as to shorten the service life of the contact elements. Therefore, there is vital significance to measure the temperature accurately and investigate the temperature effect on damage of rail surface. Aiming at the problem of components damage in high speed sliding electrical contact, the transient heat effect on the contact surface was explored and its influence and regularity on the sliding components damage was obtained. A kind of real-time temperature measurement method on rail surface of high speed sliding electrical contact is proposed. Under the condition of 2.5 kA current load, based on the principle of infrared radiation non-contact temperature sensor was used to measure the rail temperature. The dynamic distribution of temperature field was obtained through the simulation analysis, further, the connection between temperature changes and the rail surface damage morphology, the damage volume was analyzed and established. Finally, the method to reduce rail damage and improve the life of components by changing the temperature field was discussed.

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

    USGS Publications Warehouse

    Sleep, Norman 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.

  13. 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.

  14. Safety aspects of forced flow cooldown transients in Modular High Temperature Gas-Cooled Reactors

    SciTech Connect

    Kroger, P.G. )

    1993-05-01

    During some of the design basis accidents in Modular High Temperature Gas Cooled Reactors (MHTGRs), the main Heat Transport System (HTS) and the Shutdown Cooling System n removed by the passive Reactor (SCS) are assumed to have failed. Decay heat is the Cavity Cooling System (RCCS) only. If either forced flow cooling system becomes available during such a transient, its restart could significantly reduce the down-time. This report used the THATCH code to examine whether such restart, during a period of elevated core temperatures, can be accomplished within safe limits for fuel and metal component temperatures. If the reactor is scrammed, either system can apparently be restarted at any time, without exceeding any safe limits. However, under unscrammed conditions a restart of forced cooling can lead to recriticality, with fuel and metal temperatures significantly exceeding the safety limits.

  15. 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.

  16. 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.

  17. 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

  18. Transient receptor potential melastatin 8 (TRPM8) channels are involved in body temperature regulation

    PubMed Central

    2012-01-01

    Background Transient receptor potential cation channel subfamily M member 8 (TRPM8) is activated by cold temperature in vitro and has been demonstrated to act as a ‘cold temperature sensor’ in vivo. Although it is known that agonists of this ‘cold temperature sensor’, such as menthol and icilin, cause a transient increase in body temperature (Tb), it is not known if TRPM8 plays a role in Tb regulation. Since TRPM8 has been considered as a potential target for chronic pain therapeutics, we have investigated the role of TRPM8 in Tb regulation. Results We characterized five chemically distinct compounds (AMG0635, AMG2850, AMG8788, AMG9678, and Compound 496) as potent and selective antagonists of TRPM8 and tested their effects on Tb in rats and mice implanted with radiotelemetry probes. All five antagonists used in the study caused a transient decrease in Tb (maximum decrease of 0.98°C). Since thermoregulation is a homeostatic process that maintains Tb about 37°C, we further evaluated whether repeated administration of an antagonist attenuated the decrease in Tb. Indeed, repeated daily administration of AMG9678 for four consecutive days showed a reduction in the magnitude of the Tb decrease Day 2 onwards. Conclusions The data reported here demonstrate that TRPM8 channels play a role in Tb regulation. Further, a reduction of magnitude in Tb decrease after repeated dosing of an antagonist suggests that TRPM8’s role in Tb maintenance may not pose an issue for developing TRPM8 antagonists as therapeutics. PMID:22571355

  19. Transient radon signals driven by fluid pressure pulse, micro-crack closure, and failure during granite deformation experiments

    NASA Astrophysics Data System (ADS)

    Girault, Frédéric; Schubnel, Alexandre; Pili, Éric

    2017-09-01

    In seismically active fault zones, various crustal fluids including gases are released at the surface. Radon-222, a radioactive gas naturally produced in rocks, is used in volcanic and tectonic contexts to illuminate crustal deformation or earthquake mechanisms. At some locations, intriguing radon signals have been recorded before, during, or after tectonic events, but such observations remain controversial, mainly because physical characterization of potential radon anomalies from the upper crust is lacking. Here we conducted several month-long deformation experiments under controlled dry upper crustal conditions with a triaxial cell to continuously monitor radon emission from crustal rocks affected by three main effects: a fluid pressure pulse, micro-crack closure, and differential stress increase to macroscopic failure. We found that these effects are systematically associated with a variety of radon signals that can be explained using a first-order advective model of radon transport. First, connection to a source of deep fluid pressure (a fluid pressure pulse) is associated with a large transient radon emission increase (factor of 3-7) compared with the background level. We reason that peak amplitude is governed by the accumulation time and the radon source term, and that peak duration is controlled by radioactive decay, permeability, and advective losses of radon. Second, increasing isostatic compression is first accompanied by an increase in radon emission followed by a decrease beyond a critical pressure representing the depth below which crack closure hampers radon emission (150-250 MPa, ca. 5.5-9.5 km depth in our experiments). Third, the increase of differential stress, and associated shear and volumetric deformation, systematically triggers significant radon peaks (ca. 25-350% above background level) before macroscopic failure, by connecting isolated cracks, which dramatically enhances permeability. The detection of transient radon signals before rupture

  20. Electrical measurement of absolute temperature and temperature transients in a buried nanostructure under ultrafast optical heating

    NASA Astrophysics Data System (ADS)

    Yang, H. F.; Hu, X. K.; Liebing, N.; Böhnert, T.; Costa, J. D.; Tarequzzaman, M.; Ferreira, R.; Sievers, S.; Bieler, M.; Schumacher, H. W.

    2017-06-01

    We report absolute temperature measurements in a buried nanostructure with a sub-nanosecond temporal resolution. For this purpose, we take advantage of the temperature dependence of the resistance of a magnetic tunnel junction (MTJ) as detected by a fast sampling oscilloscope. After calibrating the measurement setup using steady-state electric heating, we are able to quantify temperature changes in the MTJ induced by femtosecond optical heating of the metal contact lying several 100 nm above the MTJ. We find that a femtosecond pulse train with an average power of 400 mW and a repetition rate of 76 MHz leads to a constant temperature increase of 80 K and a temporally varying temperature change of 2 K in the MTJ. The maximum temperature change in the MTJ occurs 4 ns after the femtosecond laser pulses hit the metal contact, which is supported by simulations. Our work provides a scheme to quantitatively study local temperatures in nanoscale structures and might be important for the testing of nanoscale thermal transport simulations.

  1. 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.

  2. Perceptions of temperature, moisture and comfort in clothing during environmental transients.

    PubMed

    Li, Y

    2005-02-22

    A study has been carried out to investigate the psychophysical mechanisms of the perception of temperature and moisture sensations in clothing during environmental transients. A series of wear trials was conducted to measure the psychological perception of thermal and moisture sensations and the simultaneous temperature and humidity at the skin surface, fabric surface and in the clothing under simulated moderate rain conditions. Jumpers made from wool and acrylic fibres were used in the trial. Analysis has been carried out to study the relationship between psychological perceptions of temperature and moisture and the objectively measured skin and fabric temperatures and relative humidity in clothing microclimate. The perception of warmth seems to follow Fechner's law and Stevens' power law, having positive relationships with the skin temperature and fabric temperatures. The perception of dampness appears to follow Fechner's law more closely than Stevens' power law with a negative relationship with skin temperature, and is nonlinearly and positively correlated with relative humidity in clothing microclimate. The perception of comfort is positively related to the perception of warmth and negatively to the perception of dampness. This perception of comfort is positively related to the skin temperature, which appears to follow both Fechner's law and Stevens' law, also non-linearly and negatively related to relative humidity in clothing microclimate.

  3. Studies on the effect of the temperature of intermediate fluid on the effectiveness of three fluid heat exchangers

    NASA Astrophysics Data System (ADS)

    Vasudevan, T.; Rakesh, S. G.

    2017-07-01

    Three fluid heat exchangers involving twothermal communications as well as three thermal communications have been investigated for the effect of change in the intermediate fluid temperature on the effectiveness of the heat exchangers, using both theoretical and simulation studies. The objective of these heat exchangers is identified as cooling of hot fluid. The simulations are repeated for hot fluids with different specific heats. The effect of change in the conducting material on the effectiveness in a three thermal communications heat exchanger has been investigated. The pressure drop calculations are also done for the heat exchangers.

  4. Instabilities and transient growths of the Taylor-Couette flow in stratified fluids

    NASA Astrophysics Data System (ADS)

    Park, Junho; Billant, Paul; Baik, Jong-Jin

    2015-11-01

    The Taylor-Couette flow is centrifugally unstable in inviscid limit if μ <η2 where μ =Ωo /Ωi and η =ri /ro are the ratios of angular velocity and radius between inner and outer cylinders, respectively. In the presence of stable density stratification in axial direction, there is a new instability called Strato-Rotational Instability (SRI) due to the gravity wave resonance between the two cylinders. The SRI can occur in a wider regime of μ than the Centrifugal Instability (CI) such that the stratified Taylor-Couette flow is always unstable except for the solid-body rotation. Moreover, in the regime of CI, both instabilities co-exist and dominance of these instability changes depending on the stratification. In this presentation, we will show some parametric study results on how these two instabilities behave. Moreover, it is important to study transient growth since it can be a candidate to explain subcritical transitions to turbulence in the stable regime. We will present how the transient growth behaviors change for the stratified Taylor-Couette flow in terms of effects of the stratification on the transient growth which can be explained by two different mechanisms.

  5. 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.

  6. 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.

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

    SciTech Connect

    EDWARDS, ARTHUR L.

    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 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.

  8. An advanced method for transient temperature calculation in fuel element structural analysis

    SciTech Connect

    Lassmann, K.; Preusser, T.

    1983-03-01

    An advanced method has been developed for the specific purpose of calculating temperatures in fuel element structural analysis. Fuel, cladding, coolant, and structural temperatures are treated by a single system of equations. Melting of the fuel and cladding and boiling of the coolant are included in the model. The method is compared to other solution techniques. The thermal characteristics of the finite element method (FEM) and finite difference method (FDM) transient calculations are compared. The present method includes FDM and FEM algorithms as special cases; an optimum combination of both techniques is the standard usage. Explicit, implicit, or Crank-Nicholson integration procedures are possible. The method is fast running, reliable, and has no stability problems. The new method has been implemented into the temperature calculation subcode system TEMPER for use with URANUS or other fuel element codes. Special attention has been given to user requirements (e.g., an automatic time-step control). The URANUS code, with this subcode system TEMPER, has been applied successfully to difficult fast breeder fuel rod analysis including transient overpower, loss of flow, local coolant blockage, and specific carbide fuel experiments.

  9. 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.

  10. Low temperature transient response and electroluminescence characteristics of OLEDs based on Alq3

    NASA Astrophysics Data System (ADS)

    Yuan, Chao; Guan, Min; Zhang, Yang; Li, Yiyang; Liu, Shuangjie; Zeng, Yiping

    2017-08-01

    In this work, the organic light-emitting diodes (OLEDs) based on Alq3 are fabricated. In order to make clear the transport mechanism of carriers in organic light-emitting devices at low temperature, detailed electroluminescence transient response and the current-voltage-luminescence (I-V-L) characteristics under different temperatures in those OLEDs are investigated. It founds that the acceleration of brightness increases with increasing temperature is maximum when the temperature is 200 K and it is mainly affected by the electron transport layer (Alq3). The MoO3 injection layer and the electroluminescent layer have great influence on the delay time when the temperature is 200 K. Once the temperature is greater than 250 K, the delay time is mainly affected by the MoO3 injection layer. On the contrary, the fall time is mainly affected by the electroluminescent material. The Vf is the average growth rate of fall time when the temperature increases 1 K which represents the accumulation rate of carriers. The difference between Vf caused by the MoO3 injection layer is 0.52 us/K and caused by the electroluminescent material Ir(ppy)3 is 0.73 us/K.

  11. Consequences of metallic fuel-cladding liquid phase attack during over-temperature transient on fuel element lifetime

    SciTech Connect

    Lahm, C.E.; Koenig, J.F.; Seidel, B.R.

    1990-01-01

    Metallic fuel elements irradiated in EBR-II at temperatures significantly higher than design, causing liquid phase attack of the cladding, were subsequently irradiated at normal operating temperatures to first breach. The fuel element lifetime was compared to that for elements not subjected to the over-temperature transient and found to be equivalent. 1 ref., 3 figs.

  12. 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.

  13. 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.

  14. High Temperature mechanically pumped fluid loop for space applications - working fluid selection

    NASA Technical Reports Server (NTRS)

    Paris, Anthony D.; Birur, Gajanana C.

    2004-01-01

    Mechanically pumped single-phase fluid loops are increasingly being used for heat rejection purposes in space applications. Examples of Earth orbiting missions using this technology include NSTS Shuttles (water and Freon-based loops) and the International Space Station (water and ammonia-based loops). For deep space missions, both the Mars Pathfinder (1996) and Mars Exploration Rover (2003) missions used mechanically pumped Freon-I 1 loops for their primary Heat Rejection Systems (HRS.) Mechanically pumped loops are particularly well suited for rejecting large amounts of waste heat from spacecraft and future missions incorporating components with extremely high thermal energy dissipation (e.g. radar instruments, Radioisotope-based power sources) are ideal candidates for their use. However, previous implementations of mechanically pumped loops were designed for moderate temperatures (below 6OOC) and, thus, would require relatively large radiators to reject high heat loads to space. Loops designed for a higher operating temperature would allow large amounts of heat to be rejected within the constraints of a mass efficient thermal control system.

  15. Experimental transient vane temperatures in a cascade for gas stream temperature cycling between 922 and 1644 K (1200 and 2500 F)

    NASA Technical Reports Server (NTRS)

    Gauntner, D. J.; Kaufman, A.

    1974-01-01

    Experimental transient turbine vane metal temperatures were obtained from tests conducted on air-cooled vanes installed in a four-vane cascade for a gas temperature cycled between 922 and 1644 K (1200 and 2500 F). 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 11 kelvins (20 F), simulated cruise and idle steady-state readings were repeated by the cruise and idle readings taken from the ends of a transient half-cycle at low pressure to within 17 kelvins (30 F). The tests were conducted at pressure levels of 31 and 83 N-sq cm (45 and 120 psia) with coolant temperatures of 811 and 589 K (1000 and 600 F), respectively.

  16. Light intensity and temperature affect systemic spread of silencing signal in transient agroinfiltration studies.

    PubMed

    Patil, Basavaprabhu L; Fauquet, Claude M

    2015-06-01

    RNA silencing is a sequence-specific post-transcriptional gene inactivation mechanism that operates in diverse organisms and that can extend beyond its site of initiation, owing to the movement of the silencing signal, called non-autonomous gene silencing. Previous studies have shown that several factors manifest the movement of the silencing signal, such as the size (21 or 24 nucleotides) of the secondary small interfering RNA (siRNA) produced, the steady-state concentration of siRNAs and their cognate messenger RNA (mRNA) or a change in the sink-source status of plant parts affecting phloem translocation. Our study shows that both light intensity and temperature have a significant impact on the systemic movement of the silencing signal in transient agroinfiltration studies in Nicotiana benthamiana. At higher light intensities (≥ 450 μE/m(2)/s) and higher temperatures (≥ 30 °C), gene silencing was localized to leaf tissue that was infiltrated, without any systemic spread. Interestingly, in these light and temperature conditions (≥ 450 μE/m(2) /s and ≥ 30 °C), the N. benthamiana plants showed recovery from the viral symptoms. However, the reduced systemic silencing and reduced viral symptom severity at higher light intensities were caused by a change in the sink-source status of the plant, ultimately affecting the phloem translocation of small RNAs or the viral genome. In contrast, at lower light intensities (<300 μE/m(2)/s) with a constant temperature of 25 °C, there was strong systemic movement of the silencing signal in the N. benthamiana plants and reduced recovery from virus infections. The accumulation of gene-specific siRNAs was reduced at higher temperature as a result of a reduction in the accumulation of transcript on transient agroinfiltration of RNA interference (RNAi) constructs, mostly because of poor T-DNA transfer activity of Agrobacterium, possibly also accompanied by reduced phloem translocation.

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. Full frequency-range transient solution for compressional waves in a fluid-saturated viscoacoustic porous medium

    SciTech Connect

    Carcione, J.M.; Quiroga-Goode, G.

    1996-01-01

    An analytical transient solution is obtained for propagation of compressional waves in a homogeneous porous dissipative medium. The solution, based on a generalization of Biot`s poroelastic equations, holds for the low- and high-frequency ranges, and includes viscoelastic phenomena of a very general nature, besides the Biot relaxation mechanism. The viscodynamic operator is used to model the dynamic behavior associated with the relative motion of the fluid in the pores at all frequency ranges. Viscoelasticity is introduced through the standard linear solid which allows the modeling of a general relaxation spectrum. The solution is used to study the influence of the material properties, such as bulk moduli, porosity, viscosity, permeability and intrinsic attenuation, on the kinematic and dynamic characteristics of the two compressional waves supported by the medium. The authors also obtain snapshots of the static mode arising from the diffusive behavior of the slow wave at low frequencies.

  2. 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.

  3. 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.

  4. 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.

  5. Room temperature screening of thermal conductivity by means of thermal transient measurements

    NASA Astrophysics Data System (ADS)

    García-Cañadas, Jorge; Cheng, Shudan; Márquez-García, Lourdes; Prest, Martin J.; Akbari-Rahimabadi, Ahmad; Min, Gao

    2016-10-01

    A proof of concept of the possibility to estimate thermal conductivity of bulk disc samples at room temperature by means of thermal decays is demonstrated. An experimental set-up was designed and fabricated, which is able to perform thermal transient measurements by using a specially designed multifunctional probe that has the ability to measure temperature at its tip. Initially, the probe is heated by a heater coil located in its interior until the tip temperature reaches a steady state. Then, the probe is contacted with a disc sample which produces a temperature decay until a new state is reached. The difference between the initial and final states temperatures shows a correlation with the thermal conductivity of the sample. Employing a calibration equation, obtained using reference materials, the thermal conductivity can be calculated. Reasonably good random and systematic errors (<13% and ~9% respectively) are obtained. Theoretical simulations performed using COMSOL show a good qualitative agreement with experimental results. This new method involves an inexpensive and simple set-up which can be especially useful for thermal conductivity screening and high-throughput measurements.

  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. Equations of state for fluids: empirical temperature dependence of the second virial coefficients.

    PubMed

    Tian, Jianxiang; Gui, Yuanxing

    2007-09-20

    In this paper, an empirical dependence of the second virial coefficients is derived from equations of state. The second virial coefficient B2 is found to be a linear function of 1/T1+beta, where T is the temperature and beta is a constant and has different value for different substances. Excellent experimental supports to this relationship are reported for nonpolar fluids, polar fluids, heavy globular molecule fluids, and quantum fluid He-4.

  8. Fluid structure interaction and transient cavitation tests in a T-piece pipe

    NASA Astrophysics Data System (ADS)

    Tijsseling, A. S.; Vardy, A. E.

    2005-08-01

    A physical model featuring the combined phenomena of fluid structure interaction (FSI) and vaporous cavitation is presented. The model is a closed, water-filled, T-shaped, laboratory pipe system, where the T-junction and the three closed ends are potential locations for strong FSI coupling and/or column separation. The system is suspended horizontally on long steel wires and is excited through external impact. The impact force and the static pressure of the liquid control the severity of the cavitation phenomenon.

  9. An iterative initialization procedure for transient ground temperature models with deep boundary conditions

    NASA Astrophysics Data System (ADS)

    Gruber, S.

    2009-04-01

    The initialization of deep soil thermal models is discussed here in view of two applications: (a) climate modeling, where land surface schemes comprise a soil thermal model; and (b) permafrost models. Stevens et al. (2007) and Alexeev et al. (2007) have recently demonstrated that the bottom boundary condition placement can significantly bias ground temperatures as well as the partitioning of surface energy budgets in long-term climate simulations. Addressing this problem with a deeper soil model requires dedicated initialization techniques because simple spin-up would require prohibitively long time windows, especially in the presence of frozen ground and snow cover. Physics-based models are increasingly used to estimate permafrost distribution as well as its temporal evolution, especially in mountain areas with high lateral variability of micro-climate and ground conditions. However, how can one know if the modeled presence/absence of permafrost in deeper layers is an artifact of the initialization or a valuable result? Strictly speaking, permafrost modeling with transient energy-balance and heat transfer models implicitly contains two steps: first, the finding of equilibrium conditions between the ground thermal profile and climate over one or several years and, then, possibly a transient simulation. Mean air temperature and mean ground temperature at the depth of several meters are usually related in a non-obvious way, especially in regions subject to ground freezing and snow cover. As a consequence, we cannot reliably estimate the deeper temperature profile without running the soil model - which in turn requires realistic temperatures at depth. In the method proposed to address this issue, equilibrium conditions are found by minimizing residuals between initial and final conditions of a model run over an initialization period and the near-surface part of the thermal profile. The success of this approach is judged by long-term model runs repeating only the

  10. Distributed temperature sensing based on birefringence effect on transient Brillouin grating in a polarization-maintaining photonic crystal fiber.

    PubMed

    Dong, Yongkang; Bao, Xiaoyi; Chen, Liang

    2009-09-01

    We demonstrate a time-domain distributed temperature sensing based on birefringence effect on transient Brillouin grating (TBG) in a polarization-maintaining photonic crystal fiber (PM-PCF), which uses two short pump pulses (2 ns) to excite a TBG and a long probe pulse (6 ns) to map the transient Brillouin grating spectrum (TBGS) associated with the birefringence. The 2 ns pump pulses defines a spatial resolution of 20 cm and a temperature measurement range of a few hundred degrees Celsius, and the long probe pulse provides a narrow TBGS with a temperature resolution of 0.07 degrees C.

  11. Fluid pressure, sediment compressibility, and secular and transient strain in subduction prisms: Results from ODP CORK borehole hydrologic observatories

    NASA Astrophysics Data System (ADS)

    Davis, E. E.; Becker, K.

    2005-12-01

    Instruments for long-term hydrogeological monitoring in Ocean Drilling Program boreholes have been installed in five subduction zone settings, including Cascadia, Barbados, Mariana, Costa Rica, and Nankai. Pressure records reveal a wide range of average formation states that are consistent with formation permeability and proximity to sources of formation fluid. For example, near-hydrostatic pressures (excess pore-pressure ratio λ* ~ 0) are observed in the silty parts of the Nankai accretionary prism and in the upper oceanic crust beneath the Costa Rica prism, where well-drained conditions are inferred to be present, and elevated pressures (λ* up to 0.5) have been recorded in finer-grained sedimentary sections near the toe of prisms (e.g., at the level of the decollement in the fine-grained part of the Barbados accretionary prism). In no instances have high pressures (approaching lithostatic, λ* = 1) been observed, although operational difficulties have thus far precluded installations in underthrust sediment sequences where the highest average pressures are expected to be maintained. Records often reveal non-steady behavior, with variations occurring over a broad frequency range. Tidal-frequency variations present in all records are the consequence of oceanographic loading at the seafloor. The amplitude of these signals provide constraints on formation compressibility. Estimated values vary with depth and consolidation state, and range from 5 x 10-9 to 3.5 x 10-10 Pa-1. Once these signals are removed, other transients can be observed, including ones correlated with both seismic and aseismic deformation. Secular strain has been seen in hydrologically isolated parts of the formations at several sites. At the Mariana forearc site, seismic-frequency pressure variations and persistent positive pressure changes were observed at the time of two large (Mb ~ 7.0) deep (~ 70 km) earthquakes located roughly 200 km away; these signals are inferred to reflect local formation

  12. Opioid, cannabinoid, and transient receptor potential (TRP) systems: effects on body temperature

    PubMed Central

    Rawls, Scott M.; Benamar, Khalid

    2014-01-01

    Cannabinoid and opioid drugs produce marked changes in body temperature. Recent findings have extended our knowledge about the thermoregulatory effects of cannabinoids and opioids, particularly as related to delta opioid receptors, endogenous systems, and transient receptor potential (TRP) channels. Although delta opioid receptors were originally thought to play only a minor role in thermoregulation compared to mu and kappa opioid receptors, their activation has been shown to produce hypothermia in multiple species. Endogenous opioids and cannabinoids also regulate body temperature. Mu and kappa opioid receptors are thought to be in tonic balance, with mu and kappa receptor activation producing hyperthermia and hypothermia, respectively. Endocannabinoids participate in the febrile response, but more studies are needed to determine if a cannabinoid CB1 receptor tone exerts control over basal body temperature. A particularly intense research focus is TRP channels, where TRPV1 channel activation produces hypothermia whereas TRPA1 and TRPM8 channel activation causes hyperthermia. The marked hyperthermia produced by TRPV1 channel antagonists suggests these warm channels tonically control body temperature. A better understanding of the roles of cannabinoid, opioid, and TRP systems in thermoregulation may have broad clinical implications and provide insights into interactions among neurotransmitter systems involved in thermoregulation. PMID:21622235

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. A thermodynamic framework for understanding temperature sensing by transient receptor potential (TRP) channels.

    PubMed

    Clapham, David E; Miller, Christopher

    2011-12-06

    The exceptionally high temperature sensitivity of certain transient receptor potential (TRP) family ion channels is the molecular basis of hot and cold sensation in sensory neurons. The laws of thermodynamics dictate that opening of these specialized TRP channels must involve an unusually large conformational standard-state enthalpy, ΔH(o): positive ΔH(o) for heat-activated and negative ΔH(o) for cold-activated TRPs. However, the molecular source of such high-enthalpy changes has eluded neurobiologists and biophysicists. Here we offer a general, unifying mechanism for both hot and cold activation that recalls long-appreciated principles of protein folding. We suggest that TRP channel gating is accompanied by large changes in molar heat capacity, ΔC(P). This postulate, along with the laws of thermodynamics and independent of mechanistic detail, leads to the conclusion that hot- and cold-sensing TRPs operate by identical conformational changes.

  1. 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.

  2. Extremely strong room-temperature transient photocurrent-detected magnetic resonance in organic devices

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Liu, Rui; Cai, Min; Shinar, Ruth; Shinar, Joseph

    2012-12-01

    An extremely strong room-temperature photocurrent- (PC- or IPC-) detected magnetic resonance (PCDMR) that elucidates transport and trapping phenomena in organic devices, in particular solar cells, is described. When monitoring the transient PCDMR in indium tin oxide (ITO)/poly(2-methoxy-5-(2'-ethyl)-hexoxy-1,4-phenylenevinylene) (MEH-PPV)/Al devices, where the MEH-PPV film was baked overnight at 100 °C in O2, it is observed that |ΔIPC/IPC| peaks at values ≫1, where ΔIPC is the change in IPC induced by magnetic resonance conditions. Importantly, ΔIPC and IPC are of different origin. The mechanism most likely responsible for this effect is the spin-dependent formation of spinless bipolarons adjacent to negatively charged deep traps, apparently induced in particular by oxygen centers, to form trions.

  3. 3D transient model to predict temperature and ablated areas during laser processing of metallic surfaces

    NASA Astrophysics Data System (ADS)

    Naghshine, Babak. B.; Kiani, Amirkianoosh

    2017-02-01

    Laser processing is one of the most popular small-scale patterning methods and has many applications in semiconductor device fabrication and biomedical engineering. Numerical modelling of this process can be used for better understanding of the process, optimization, and predicting the quality of the final product. An accurate 3D model is presented here for short laser pulses that can predict the ablation depth and temperature distribution on any section of the material in a minimal amount of time. In this transient model, variations of thermal properties, plasma shielding, and phase change are considered. Ablation depth was measured using a 3D optical profiler. Calculated depths are in good agreement with measured values on laser treated titanium surfaces. The proposed model can be applied to a wide range of materials and laser systems.

  4. 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.

  5. Transient temperature rise in a mouse due to low-frequency regional hyperthermia

    NASA Astrophysics Data System (ADS)

    Trakic, Adnan; Liu, Feng; Crozier, Stuart

    2006-04-01

    A refined nonlinear heat transfer model of a mouse has been developed to simulate the transient temperature rise in a neoplastic tumour and neighbouring tissue during regional hyperthermia using a 150 kHz inductive coil. In this study, we incorporate various bio-energetic enhancements to the heat transfer equation and numerical validations based on experimental findings for the mouse, in terms of nonlinear metabolic heat production, homeothermy, blood perfusion parameters, thermoregulation, psychological and physiological effects. The discretized bio-heat transfer equation has been validated with the commercial software FEMLAB on a canonical multi-sphere object before applying the scheme to the inhomogeneous mouse voxel phantom. The time-dependent numerical results of regional hyperthermia of mouse thigh have been compared with the available experimental temperature results with only a few small disparities. During the first 20 min of local unfocused heating, the temperature in the tumour and the surrounding tissue increased by around 7.5 °C. The objective of this preliminary study was to develop a validated electrothermal numerical scheme for inductive hyperthermia of a small mammal with the intention of expanding the model into a complete numerical solution involving ferromagnetic nanoparticles for targeted heating of tumours at low frequencies. In addition, the numerical scheme herein could assist in optimizing and tailoring of focused electromagnetic fields for hyperthermia.

  6. Simplified simulation of the transient behavior of temperatures in the upper shaft of the blast furnace

    SciTech Connect

    Saxen, H.

    1998-06-01

    The blast furnace is the principal process in the world for production of iron for primary steelmaking. The furnace acts as a huge countercurrent heat exchange and chemical reactor with complicated heat and mass transfer phenomena and chemical reactions. The flows of burden and gas in the blast furnace shaft strongly affect the fuel economy of the process. An optimal gas flow distribution, which is obtained by controlling the burden distribution, leads to a high utilization degree of the reducing gas, smooth burden descent, and little wear of the furnace lining. Here, a one-dimensional dynamic model of the upper part of the blast furnace shaft is applied to study the evolution of gas and burden temperatures, mainly in order to shed light on the transient phenomena after charging dumps of burden. The effects of irregularities in the burden descent and charging are also studied briefly. The simulations demonstrate that the temperatures of the burden layers in the lower part of the simulated region assume a quasi-steady state, indicating that the changes in the top gas temperature experienced immediately after a dump of burden arise primarily because of heat transfer between the gas and the dump. These results support the idea that such temporary changes can be interpreted in terms of distribution of the dumps on the burden surface.

  7. 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)

  8. Temperature and electrical conductivity of the lunar interior from magnetic transient measurements in the geomagnetic tail

    NASA Technical Reports Server (NTRS)

    Dyal, P.; Parkin, C. W.; Daily, W. D.

    1974-01-01

    Magnetometers were deployed at four Apollo sites on the moon to measure remanent and induced lunar magnetic fields. Measurements from this network of instruments were used to calculate the electrical conductivity, temperature, magnetic permeability, and iron abundance of the lunar interior. Global lunar fields due to eddy currents, induced in the lunar interior by magnetic transients in the geomagnetic tail field, were analyzed to calculate an electrical conductivity profile for the moon: the conductivity increases rapidly with depth from 10 to the minus 9 power mhos/meter at the lunar surface to .0001 mhos/meter at 200 km depth, then less rapidly to .02 mhos/meter at 1000 km depth. A temperature profile is calculated from conductivity: temperature rises rapidly with depth to 1100 K at 200 km depth, then less rapidly to 1800 K at 1000 km depth. Velocities and thicknesses of the earth's magnetopause and bow shock are estimated from simultaneous magnetometer measurements. Average speeds are determined to be about 50 km/sec for the magnetopause and 70 km/sec for the bow shock, although there are large variations in the measurements for any particular boundary crossing.

  9. 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.

  10. 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.

  11. 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.

  12. Effect of irrigation fluid temperature on core temperature and hemodynamic changes in transurethral resection of prostate under spinal anesthesia

    PubMed Central

    Singh, Rajeev; Asthana, Veena; Sharma, Jagdish P.; Lal, Shobha

    2014-01-01

    Background: Hypothermia is a frequent observation in elderly males undergoing transurethral resection of prostate (TURP) under spinal anesthesia. The use of irrigating fluids at room temperature results in a decrease body temperature. Warmed irrigating solutions have shown to reduce heat loss and the resultant shivering. Such investigation was not much tried in low resource settings. Aim: To compare the resultant change in core temperature and hemodynamic changes among patients undergoing TURP surgery under spinal anesthesia using warm and room temperature irrigation fluids. Settings and Design: Randomized prospective study at a tertiary care center. Methods: This study was conducted on 40 male patients aged 50-85 years undergoing TURP under spinal anesthesia. Of which, 20 patients received irrigation fluid at room temperature 21°C and 20 patients received irrigation fluid at 37°C after random allocation. Core temperatures and hemodynamic parameters were assessed in all patients at preoperative, intra-operative, and postoperative periods. Intra-operative shivering was also noted in both groups. Statistical Analysis: Unpaired and Paired Student's t-test. Results: For patients who underwent irrigation with fluid at room temperature Core temperature drop from 36.97°C in preoperative to 34.54°C in postoperative period with an effective difference of 2.38°C. Among patients who received warmed irrigation fluid at 37°C had core temperature drop from 36.97°C to 36.17°C and the effect of fall was 0.8°C. This difference was statistically significant (P < 0.001). Shivering of Grades 1 and 2 was observed in nine patients, of Group 1 while only three patients had Grades 1 and 2 shivering in Group 2. The hemodynamic parameters were similar in the two groups and did not reach significant difference. Conclusion: Use of warm irrigation fluid during TURP reduces the risk of perioperative hypothermia and shivering. PMID:25886228

  13. Transient tension changes initiated by laser temperature jumps in rabbit psoas muscle fibres.

    PubMed Central

    Goldman, Y E; McCray, J A; Ranatunga, K W

    1987-01-01

    1. A technique was developed to generate 2-8 degrees C step temperature perturbations (T-jumps) in single muscle fibres to study the thermodynamics of muscle contraction. A solid-state pulsed holmium laser emitting at 2.065 microns heated the fibre and surrounding solution in approximately 150 mus. The signal from a 100 microns thermocouple fed back to a heating wire maintained the elevated temperature after the laser pulse. 2. Tension of glycerol-extracted muscle fibres from rabbit psoas muscle did not change significantly following T-jumps when the fibre was relaxed. 3. In rigor, tension decreased abruptly on heating indicating normal (not rubber-like) thermoelasticity. The thermoelastic coefficient (negative ratio of relative length change to relative temperature change) of the fibre was estimated to be -0.021 at sarcomere lengths of 2.5-2.8 microns. Rigor tension was constant after the temperature step and returned to the original value on recooling. 4. In maximal Ca2+ activation, tension transients initiated by T-jumps had several phases. An immediate tension decrease suggests that thermoelasticity during contraction is similar to that in rigor. Active tension then recovered to the value before the T-jump with an apparent rate constant of approximately 400 s-1 (at 10-20 degrees C). This rate constant did not have an appreciable dependence on the final temperature. Finally, tension increased exponentially to a new higher level with a rate constant of approximately 20 s-1 at 20 degrees C. This rate constant increased with temperature with a Q10 of 1.4. 5. At submaximal Ca2+ activation the tension rise was followed by a decay to below the value before the T-jump. This decline was expected from the temperature dependence of steady pCa-tension curves. The final tension decline occurred on the 1-5 s time scale. 6. The value and amplitude dependence of the rate constant for the quick recovery following T-jumps were similar to those of the quick recovery following

  14. Heat-conduction error of temperature sensors in a fluid flow with nonuniform and unsteady temperature distribution.

    PubMed

    Khine, Soe Minn; Houra, Tomoya; Tagawa, Masato

    2013-04-01

    In temperature measurement of non-isothermal fluid flows by a contact-type temperature sensor, heat conduction along the sensor body can cause significant measurement error which is called "heat-conduction error." The conventional formula for estimating the heat-conduction error was derived under the condition that the fluid temperature to be measured is uniform. Thus, if we apply the conventional formula to a thermal field with temperature gradient, the heat-conduction error will be underestimated. In the present study, we have newly introduced a universal physical model of a temperature-measurement system to estimate accurately the heat-conduction error even if a temperature gradient exists in non-isothermal fluid flows. Accordingly, we have been able to successfully derive a widely applicable estimation and/or evaluation formula of the heat-conduction error. Then, we have verified experimentally the effectiveness of the proposed formula using the two non-isothermal fields-a wake flow formed behind a heated cylinder and a candle flame-whose fluid-dynamical characteristics should be quite different. As a result, it is confirmed that the proposed formula can represent accurately the experimental behaviors of the heat-conduction error which cannot be explained appropriately by the existing formula. In addition, we have analyzed theoretically the effects of the heat-conduction error on the fluctuating temperature measurement of a non-isothermal unsteady fluid flow to derive the frequency response of the temperature sensor to be used. The analysis result shows that the heat-conduction error in temperature-fluctuation measurement appears only in a low-frequency range. Therefore, if the power-spectrum distribution of temperature fluctuations to be measured is sufficiently away from the low-frequency range, the heat-conduction error has virtually no effect on the temperature-fluctuation measurements even by the temperature sensor accompanying the heat-conduction error in

  15. Estimation of the equilibrium formation temperature in the presence of bore fluid invasion

    NASA Astrophysics Data System (ADS)

    Poulsen, Søren Erbs; Nielsen, Søren Bom; Balling, Niels

    2012-09-01

    Bottom hole temperatures (BHTs) measured during drilling operations are thermally disturbed by the drilling process. This paper presents a method, CSMI (Cylindrical Source Model with Invasion of bore mud filtrate), for estimating equilibrium formation temperatures with probability distributions from BHT measurements in the presence of bore fluid invasion. The scheme is based on finite element analysis in conjunction with Markov chain Monte Carlo inversion. The axisymmetric forward model assumes a cylindrical source of finite radius and contrasting thermal parameters, which includes the possibility of invasion (advection) of mud filtrate into the formation. In a synthetic example, it is demonstrated that given bore fluid invasion and a low and high temperature of the bore mud and formation, respectively, the equilibrium formation temperature and the uncertainty hereon is underestimated by correction schemes based on purely conductive models. The influence of the borehole radius and fluid invasion on the temperature measured at the borehole axis attenuates over time. It is further demonstrated that the invasion radius and the matrix thermal conductivity cannot be estimated simultaneously with the CSMI scheme. The analysis of five BHT records measured onshore Denmark, for which the equilibrium formation temperature is known, shows that CSMI temperatures based on single datum records are highly uncertain because of a strong negative coupling between the temperature of the mud filtrate and the equilibrium formation temperature. For records with multiple temperature measurements, the CSMI scheme matches statistically the measured equilibrium formation temperatures. It is further shown that additional negative bias is added to Horner plot temperatures if bore fluid invasion has occurred. Allowing for bore fluid invasion in addition to a borehole of finite radius and contrasting thermal parameters, increases temperature estimates by 5 per cent (4-7 per cent) on average

  16. Shaken. Not stirred-temperature change and heat loss during delivery of IV fluids

    PubMed

    Fields; Hsu

    2000-10-01

    Microwave-heated intravenous fluids are used in the rewarming of hypothermic patients. OBJECTIVES: To study the effect of both shaking of the microwaved bag and heat loss during delivery. METHODS: Twenty 1-liter normal saline bags were heated individually in a commercial microwave, immediately randomized into a "shaken" or a "non-shaken" group. The temperature of the fluid was recorded initially out of the bag and then at one-minute intervals by a blinded observer as the fluid ran "wideopen" through ambient temperature tubing. RESULTS: No statistically significant temperature difference occurred in any of the measured time intervals between the shaken and the non-shaken bags. Seventy percent of the overall temperature losses occurred in the first three minutes out of the microwave for both groups. CONCLUSIONS: Absence of shaking of the microwaved fluids does not produce "hot spots." Higher initial temperatures out of the bag should be considered as well as warming of the IV tubing.

  17. Electric heating for high-temperature heat transport fluids

    NASA Astrophysics Data System (ADS)

    Holmes, J. T.

    1985-12-01

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

  18. 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.

  19. Rectal Instillation of Cold Fluids for Targeted Temperature Management After Cardiac Arrest: A Case Report.

    PubMed

    Markota, Andrej; Fluher, Jure; Sinkovič, Andreja

    2017-07-14

    The optimal method of temperature management after cardiac arrest remains unknown. Methods that are most effective are usually invasive and expensive. Noninvasive methods are not as effective and obstruct access to the patient. Temperature management via rectal cooling offers some potential advantages in survivors of cardiac arrest, namely, relatively large volumes of temperature-controlled fluids can be instilled, access to the patient is not obstructed, and fluid overload can be ameliorated by removal of a fraction of instilled fluid. We used rectal cooling in a 72-year-old male comatose survivor of cardiac arrest with an initial body temperature of 36.8°C. We instilled 3000 mL of normal saline at 4°C in 75 minutes, and ∼2000 mL of effluent fluid was removed via gravity at 105 minutes after instillation. At 135 minutes, temperature decreased to a minimum of 35.2°C. No leakage was observed. Standard procedures (insertion of central venous and arterial catheters, electrocardiography, echocardiography, chest radiography) were performed with a rectal catheter in situ. At 210 minutes after instillation, the catheter was removed and there were no clinical signs of rectal injury after removal. To conclude, rectal instillation of cold fluids resulted in a significant decrease of body temperature and we observed no major side effects. Fluid overloading was avoided by removing effluent fluid. Additional studies are needed if this technique is to gain more widespread use.

  20. Thermographic NDT based on transient temperature field under Joule effect heating

    SciTech Connect

    Sakagami, Takahide; Ogura, Keiji

    1994-12-31

    The thermographic NDT based on the transient temperature distribution under the Joule effect heating by an electric current was discussed. Two different types of inspection methods, i.e., the singular method and the insulation method were examined. The singular method based on the heat concentration at the crack tip was successfully applied to the identification of the through-thickness and surface cracks embedded in steel plates. The resolution of the crack identification by the singular method was examined by the current intensity factor and the thermal diffusion length. The insulation method based on the temperature turbulence appears on the sample surface due to the thermal insulation of the defect was tested for the identification of the delaminated defect in CFRP. Two methods of the Joule effect heating, the direct current application and the induction heating, were successfully applied for the thermographic NDT of the delaminated defects in CFRP samples. The thermographic NDT developed in this study was found to be applicable to nondestructive flaw- and defect-inspection both in metallic and composite materials.

  1. Effects of transient high temperature treatment on the intestinal flora of the silkworm Bombyx mori.

    PubMed

    Sun, Zhenli; Kumar, Dhiraj; Cao, Guangli; Zhu, Liyuan; Liu, Bo; Zhu, Min; Liang, Zi; Kuang, Sulan; Chen, Fei; Feng, Yongjie; Hu, Xiaolong; Xue, Renyu; Gong, Chengliang

    2017-06-13

    The silkworm Bombyx mori is a poikilotherm and is therefore sensitive to various climatic conditions. The influence of temperature on the intestinal flora and the relationship between the intestinal flora and gene expression in the silkworm remain unknown. In the present study, changes of the intestinal flora at 48, 96 and 144 h following transient high temperature treatment (THTT) of 37 °C for 8 h were investigated. According to principal component analysis, the abundances of Enterococcus and Staphylococcus showed a negative correlation with other dominant genera. After THTT, the gene expression levels of spatzle-1 and dicer-2 were increased and decreased, respectively, which suggested that the Toll and RNAi pathways were activated and suppressed, respectively. The species-gene expression matrix confirmed that the spatzle-1 and dicer-2 gene expression levels were negatively and positively correlated, respectively, with the abundance of Enterococcus and Staphylococcus in the control. The abundance of Variovorax post-THTT was positively correlated with the spatzle-1 gene expression level, whereas the community richness of Enterococcus was negatively correlated with the spatzle-1 gene expression level and positively correlated with the dicer-2. The results of the present investigation provide new evidence for understanding the relationships among THTT, intestinal flora and host gene expression.

  2. Temperature responsive hydrogels enable transient three-dimensional tumor cultures via rapid cell recovery.

    PubMed

    Heffernan, John M; Overstreet, Derek J; Srinivasan, Sanjay; Le, Long D; Vernon, Brent L; Sirianni, Rachael W

    2016-01-01

    Recovery of live cells from three-dimensional (3D) culture would improve analysis of cell behaviors in tissue engineered microenvironments. In this work, we developed a temperature responsive hydrogel to enable transient 3D culture of human glioblastoma (GBM) cells. N-isopropylacrylamide was copolymerized with hydrophilic grafts and functionalized with the cell adhesion peptide RGD to yield the novel copolymer poly(N-isopropylacrylamide-co-Jeffamine(®) M-1000 acrylamide-co-hydroxyethylmethacrylate-RGD), or PNJ-RGD. This copolymer reversibly gels in aqueous solutions when heated under normal cell culture conditions (37°C). Moreover, these gels redissolve within 70 s when cooled to room temperature without the addition of any agents to degrade the synthetic scaffold, thereby enabling rapid recollection of viable cells after 3D culture. We tested the efficiency of cell recovery following extended 3D culture and were able to recover more than 50% of viable GBM cells after up to 7 days in culture. These data demonstrate the utility of physically crosslinked PNJ-RGD hydrogels as a platform for culture and recollection of cells in 3D. © 2015 Wiley Periodicals, Inc.

  3. Fluid temperatures: Modeling the thermal regime of a river network

    Treesearch

    Rhonda Mazza; Ashley Steel

    2017-01-01

    Water temperature drives the complex food web of a river network. Aquatic organisms hatch, feed, and reproduce in thermal niches within the tributaries and mainstem that comprise the river network. Changes in water temperature can synchronize or asynchronize the timing of their life stages throughout the year. The water temperature fluctuates over time and place,...

  4. Effect of temperature and small amounts of metal ions on transient chaos in the batch Belousov Zhabotinsky system

    NASA Astrophysics Data System (ADS)

    Didenko, Olga Z.; Strizhak, Peter E.

    2001-05-01

    We report an effect of temperature and small amounts of metal ions on transient chaotic regime observed in the batch Belousov-Zhabotinsky oscillating chemical reaction catalyzed by ferroin. The transient chaos is quantified by values of the largest Lyapunov exponent and induction period. We have found that these values depend through the Arrhenius equation on the temperature if the initial ferroin concentration is varied in the range of (0.87-3.5)×10 -3 M. We show that inside this range transient chaos is characterized by linear response to injection of solutions containing metal ions, e.g., cerium(III), manganese(II), vanadyl(IV) or thallium(I).

  5. Standard test method for low-temperature viscosity of automotive fluid lubricants measured by Brookfield viscometer

    SciTech Connect

    Not Available

    1980-01-01

    This method describes the use of the Brookfield viscometer for the determination of the low-shear-rate viscosity of automotive fluid lubricants in the temperature range from -5 to -40/sup 0/C. The viscosity range is 1000 to 1,000,000 cP (mPa.s). A lubricant fluid sample is cooled in an air bath at test temperature for 16 h. It is carried in an insulated container to a nearby Brookfield viscometer where its Brookfield viscosity is measured at any test temperature in the range from -5 to -40/sup 0/C. The low-temperature, low-shear-rate viscosity of gear oils, automatic transmission fluids, torque and tractor fluids, and industrial and automotive hydraulic oils are frequently specified by Brookfield viscosities.

  6. Properties of planetary fluids at high pressure and temperature

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  7. 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.

  8. Influence of shear history at bottomhole temperature on fracturing-fluid efficiency

    SciTech Connect

    Harris, P.C.; Penny, G.S.

    1989-05-01

    The effects of downhole environmental conditions on fracturing-fluid rheology and leakoff were evaluated in a flow loop at simulated fracture conditions. Linear and crosslinked gel fluids were subjected to shear rates of 50 to 100 seconds/sup -1/ past core for 4 hours at temperatures of 75 to 250/sup 0/F (24 to 121/sup 0/C). Nonlinear effects commonly observed with crosslinked gel fluids diminished as the fluid was sheared. Shearing for 30 minutes to 4 hours at 100 seconds/sup -1/ before a fluid-loss test was run resulted in leakoff following square-root-of-time behavior. Spurt loss increased for crosslinked gel fluids as the fluid degraded, whether by enzyme or oxidative mechanism. The leakoff coefficient decreased slightly with time under shearing conditions. Although the polymer was breaking, the absolute amount of polymer available for deposition did not change. The apparent viscosity of fluid remaining within the fracture was also investigated. During initial fluid leakoff, polymer was concentrated as a gel filter cake at the fracture face. Once an equilibrium filter-cake thickness was achieved, however, fluid loss to the formation resulted in an increase in the polymer concentration in the remaining fluid and hence an increase in apparent viscosity.

  9. Charge recombination reactions in photosystem II. 2. Transient absorbance difference spectra and their temperature dependence.

    PubMed

    Hillmann, B; Brettel, K; van Mieghem, F; Kamlowski, A; Rutherford, A W; Schlodder, E

    1995-04-11

    Absorbance difference spectra of the transient states in photosystem II (PS II) have been examined in the Qv absorption region between 660 and 700 nm. The P680+Pheo-/P680Pheo, 3P680/P680, and P680+QA-/P680QA spectra were measured in O2-evolving PS II core complexes from Synechococcus and PS II-enriched membrane fragments from spinach. The low-temperature absorbance difference spectra vary only slightly between both PS II preparations. The 3P680/P680 spectrum is characterized by a bleaching at 685 nm at 25 K and indicates weak exciton coupling with neighboring pigment(s). We conclude that P680 absorbs at 685 nm in more intact PS II preparations at cryogenic temperature. The difference spectra of the radical pairs are strongly temperature dependent. At low temperature the P680+QA-/P680QA- spectrum exhibits the strongest bleaching at 675 nm whereas the P680+Phe-/P680Pheo spectra show two distinct bleaching bands at 674 and 684 nm. It is suggested that an electrochronic red shift resulting in a bleaching at 675 nm and an absorbance increase at about 682 nm dominates the spectral features of the charge-separated states. On the basis of the present results and those in the literature, we conclude that the interactions between the pigments and especially the organization of the primary donor must be quite different in PS II compared to bacterial reaction centers, although the basic structural arrangement of the pigments might be similar. Spectral data obtained with samples in the presence of singly and doubly reduced QA indicate that the primary photochemistry in PS II is not strongly influenced by the redox state of QA at low temperature and confirm the results of the accompanying paper [Van Mieghem, F. J. E., Brettel, K., Hillmann, B., Kamlowski, A., Rutherford, A. W., & Schlodder, E. (1995) Biochemistry 34, 4798-4813]. The spectra of the primary radical pair and the reaction center triplet obtained with more intact PS II preparations differ widely from those of D1/D2

  10. 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.

  11. Temperature-sensitive transient receptor potential channels in corneal tissue layers and cells.

    PubMed

    Mergler, Stefan; Valtink, Monika; Takayoshi, Sumioka; Okada, Yuka; Miyajima, Masayasu; Saika, Shizuya; Reinach, Peter S

    2014-01-01

    We here provide a brief summary of the characteristics of transient receptor potential channels (TRPs) identified in corneal tissue layers and cells. In general, TRPs are nonselective cation channels which are Ca(2+) permeable. Most TRPs serve as thermosensitive molecular sensors (thermo-TRPs). Based on their functional importance, the possibilities are described for drug-targeting TRP activity in a clinical setting. TRPs are expressed in various tissues of the eye including both human corneal epithelial and endothelial layers as well as stromal fibroblasts and stromal nerve fibers. TRP vanilloid type 1 (TRPV1) heat receptor, also known as capsaicin receptor, along with TRP melastatin type 8 (TRPM8) cold receptor, which is also known as menthol receptor, are prototypes of the thermo-TRP family. The TRPV1 functional channel is the most investigated TRP channel in these tissues, owing to its contribution to maintaining tissue homeostasis as well as eliciting wound healing responses to injury. Other thermo-TRP family members identified in these tissues are TRPV2, 3 and 4. Finally, there is the TRP ankyrin type 1 (TRPA1) cold receptor. All of these thermo-TRPs can be activated within specific temperature ranges and transduce such inputs into chemical and electrical signals. Although several recent studies have begun to unravel complex roles for thermo-TRPs such as TRPV1 in corneal layers and resident cells, additional studies are needed to further elucidate their roles in health and disease.

  12. Transient 21st Century Changes in Daily-Scale Temperature Extremes in the United States

    NASA Astrophysics Data System (ADS)

    Scherer, M.; Diffenbaugh, N. S.

    2012-12-01

    A key question for policy and adaptation decisions is how quickly significant changes in temperature extremes will emerge as greenhouse gas concentrations increase and whether that emergence will be uniform between hot and cold extremes and across different geographic areas. We therefore use a high-resolution, multi-member ensemble climate model experiment driven by the A1B emission scenario to investigate the transient changes in the frequency, duration and magnitude of six daily-scale hot and cold extreme indices throughout the 21st century in the United States. We evaluate these changes within a time of emergence framework and calculate the emergence of a permanent exceedence above the colder part of the current (1980-2009) extremes distribution, and further analyze whether a new norm, with the distribution centered on the current distribution's maxima/minima, emerges. We find that hot extremes will permanently exceed the current distribution's colder half in large parts of the U.S. during the 21st century, along with the emergence of a new hot extremes norm. The changes are particularly robust for tropical nights in the Eastern U.S. and for the exceedence of the 95th daily-maximum-temperature percentile in the West and the Northeast. Conversely, no widespread emergence for a permanent exceedence or a new norm is found for cold extremes, with the exception of cold spell duration and frost day frequency. Accordingly, our analysis implies unprecedented heat stress in many parts of the U.S. by the mid century under increase radiative forcing, as well as cold extremes that, although less frequent, remain at least occasionally as long and as severe as in the current climate.

  13. Effects of a transient sea surface temperature anomaly on the energetics of the Mintz-Arakawa model atmosphere

    NASA Technical Reports Server (NTRS)

    Chow, S. H.

    1974-01-01

    The possible response of the atmosphere, as simulated by the two level Mintz-Arakawa global general circulation model, to a transient North Pacific sea surface temperature anomaly is investigated in terms of the energetics both in the spatial and wave number domains. Results indicate that the transient SST variations of reasonable magnitude in the North Pacific Ocean can induce a disturbing effect on the global energetics both in the spatial and wave number domains. The ability of the two level Mintz-Arakawa model to simulate the atmospheric energetics is also examined. Except in the tropics, the model exhibits a reasonable and realistic energy budget.

  14. Diels-Alder reactions in high temperature fluids

    SciTech Connect

    Manka, M.J.; Jeffers, J.M.

    1988-08-01

    While free radical reactions are thought to be the primary chemical mechanism for gas phase soot formation at combustion temperatures, Deils-Alder condensation reactions may be important in the formation of cyclic hydrocarbon species leading to aromatic hydrocarbons in pyrolytic-processes at lower temperatures which suffer from carbon formation. In order to evaluate the importance of Diels-Alder reactions in the formation of carbon, accurate kinetic rate data is needed for proper chemical modeling efforts. Diels-Alder reactions have been extensively studied in the gas and liquid phases. Since the reaction is a condensation reaction, the rate constant has a significant pressure as well as a temperature dependence. We report in this paper the results of reaction rate measurements of 1,3-cyclohexadiene with itself. We also report the effect of pressure on the kinetic rate constant for the pressure range 4000-18,000 kPa and the temperature range 200-250/degree/C.

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

    SciTech Connect

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

    1984-09-01

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

  16. Influence of beverage temperature on palatability and fluid ingestion during endurance exercise: a systematic review.

    PubMed

    Burdon, Catriona A; Johnson, Nathan A; Chapman, Phillip G; O'Connor, Helen T

    2012-06-01

    Beverage palatability is known to influence fluid consumption during exercise and may positively influence hydration status and help prevent fatigue, heat illness, and decreased performance. The aims of this review were to evaluate the effect of beverage temperature on fluid intake during exercise and investigate the influence of beverage temperature on palatability. Citations from multiple databases were searched from the earliest record to November 2010 using the terms beverage, fluid, or water and palatability, preference, feeding, and drinking behavior and temperature. Included studies (N = 14) needed to use adult (≥18 yr) human participants, have beverage temperatures ≤50 °C, and measure consumption during exercise and/or palatability. All studies reporting palatability (n = 10) indicated that cold (0-10 °C) or cool (10-22 °C) beverages were preferred to warmer ones (control, ≥22 °C). A meta-analysis on studies reporting fluid consumption (n = 5) revealed that participants consumed ~50% (effect size = 1.4, 0.75-2.04, 95% CI) more cold/cool beverages than control during exercise. Subanalysis of studies assessing hydration status (n = 4) with consumption of cool/cold vs. warm beverages demonstrated that dehydration during exercise was reduced by 1.3% of body weight (1.6-0.9%, 95% CI; p < .001). Cool beverage temperatures (<22 °C) significantly increased fluid palatability, fluid consumption, and hydration during exercise vs. control (≥22 -°C).

  17. Bacillus spore inactivation differences after combined mild temperature and high pressure processing using two pressurizing fluids.

    PubMed

    Robertson, Rosalind E; Carroll, Tim; Pearce, Lindsay E

    2008-06-01

    Spores of six species (28 strains) of dairy Bacillus isolates were added to sterile reconstituted skim milk and pressure processed (600 MPa for 60 s at 75 degrees C) using either a water-based pressurizing fluid or silicon oil. Processing temperatures peaked at 88 and 90 degrees C, respectively, for both fluids. For all strains, the log inactivation was consistently higher in the silicon oil than in the water-based fluid. This has potential implications for food safety assessment of combined pressure-temperature processes. High pressure processing causes mild heating during pressurization of both the target sample (i.e., spores) and the pressurizing fluid used for pressure delivery. Primarily, the adiabatic heat of compression of the fluids as well as other heat-transfer properties of the fluids and equipment determines the magnitude of this heating. Pressure cycles run with silicon oil were 7 to 15 degrees C higher in temperature during pressurization than pressure cycles run with the water-based pressurizing fluid, due to the greater adiabatic heat of compression of silicon oil. At and around the target pressure, however, the temperatures of both pressurizing fluids were similar, and they both dropped at the same rate during the holding time at the target pressure. We propose that the increased spore inactivation in the silicon oil system can be attributed to additional heating of the spore preparation when pressurized in oil. This could be explained by the temperature difference between the silicon oil and the aqueous spore preparation established during the pressurization phase of the pressure cycle. These spore-inactivation differences have practical implications because it is common practice to develop inactivation kinetic data on small, jacketed laboratory systems pressurized in oil, with extensive heat loss. However, commercial deployment is invariably on large industrial systems pressurized in water, with limited heat loss. Such effects should be

  18. Transient twenty-first century changes in daily-scale temperature extremes in the United States

    NASA Astrophysics Data System (ADS)

    Scherer, Martin; Diffenbaugh, Noah S.

    2014-03-01

    A key question for climate mitigation and adaptation decisions is how quickly significant changes in temperature extremes will emerge as greenhouse gas concentrations increase, and whether that emergence will be uniform between hot and cold extremes and across different geographic areas. We use a high-resolution, multi-member ensemble climate model experiment over the United States (U.S.) to investigate the transient response of the annual frequency, duration and magnitude of 8 daily-scale extreme temperature indices during the twenty-first century of the A1B emissions scenario. We evaluate the time of emergence of a permanent exceedance (PE) above the colder part of the historical (1980-2009) extremes distribution, and the time of emergence of a new norm (NN) centered on the historical maxima (for hot extremes) or minima (for cold extremes). We find that during the twenty-first century, hot extremes permanently exceed the historical distribution's colder half over large areas of the U.S., and that the hot extremes distribution also becomes centered on or above the historical distribution's maxima. The changes are particularly robust for the exceedance of the annual 95th percentile of daily maximum temperature over the West and the Northeast (with the earliest emergence of a PE by 2030 and of a NN by 2040), for warm days over the Southwest (with the earliest emergence of a PE by 2020 and of a NN by 2030), and tropical nights over the eastern U.S. (with the earliest emergence of a PE by 2020 and of a NN by 2030). Conversely, no widespread emergence of a PE or a NN is found for most cold extremes. Exceptions include frost day frequency (with a widespread emergence of a PE below the historical median frequency by 2030 and of a NN by 2040 over the western U.S.), and cold night frequency (with an emergence of a PE below the historical median frequency by 2040 and of a NN by 2060 in virtually the entire U.S.). Our analysis implies a transition over the next half century

  19. Simultaneous 2-D Measurements of Transient Velocity and Temperature Fields in a Thermal Starting Plume: Laboratory Models of Entrainment and Structure of Mantle Plumes

    NASA Astrophysics Data System (ADS)

    Kumagai, I.; Yanagisawa, T.; Kurita, K.

    2002-12-01

    Both numerical and experimental models of thermal plumes suggest that mantle plumes entrain surrounding mantle and their morphology (temperature and compositional fields in the plume head) evolves as they rise. Recent geochemical and isotopic studies of mantle plume products have revealed mixing of the ambient mantle with the primitive plume source. In order to make a quantitative comparison of the geophysical modeling with geological evidences, it is desired to show a precise image of spatial and temporal evolution of temperature and compositional fields in the plumes. Here, we present preliminary results of our laboratory experiments on thermal starting plumes using a quantitative technique of digital image processing. By coupling Particle Image Velocimetry (PIV) with Laser Induced Fluorescence (LIF) we can measure simultaneous 2-dimensional transient velocity and temperature fields in a thermal plume. Our experiments were conducted in a transparent rectangular tank containing a viscous fluid. Buoyancy in the form of heat was injected into the fluid by operating a heater at the base of the tank. The flow was marked with tracer particles for velocity and with the fluorescence dye, Rhodamine B, for temperature measurements. The particles and the fluorescence dye were illuminated and exited by a thin vertical sheet of laser light that was oriented to contain the axis of symmetry. We succeeded in simultaneous measurements of ascent velocity of the plume head, precise velocity field within the plume head, and evolution of the temperature field. This makes clear their relation and is useful for considering the entrainment process of plumes. Our aim of this study is to clarify the physics of entrainment and mixing phenomena of starting plumes, and to make quantitative geophysical models of mantle plumes connecting with geological and seismic evidences. In this presentation, we will show that this quantitative technique is a powerful tool for approaching these issues.

  20. A New Model for Temperature Jump at a Fluid-Solid Interface

    PubMed Central

    Shu, Jian-Jun; Teo, Ji Bin Melvin; Chan, Weng Kong

    2016-01-01

    The problem presented involves the development of a new analytical model for the general fluid-solid temperature jump. To the best of our knowledge, there are no analytical models that provide the accurate predictions of the temperature jump for both gas and liquid systems. In this paper, a unified model for the fluid-solid temperature jump has been developed based on our adsorption model of the interfacial interactions. Results obtained from this model are validated with available results from the literature. PMID:27764230

  1. Model energy landscapes of low-temperature fluids: Dipolar hard spheres.

    PubMed

    Matyushov, Dmitry V

    2007-07-01

    An analytical model of non-Gaussian energy landscape of low-temperature fluids is developed based on the thermodynamics of the fluid of dipolar hard spheres. The entire excitation profile of the liquid, from the high-temperature liquid to the point of ideal-glass transition, has been obtained from Monte Carlo simulations. The fluid of dipolar hard spheres loses stability close to the point of ideal-glass transition transforming via a first-order transition into a columnar liquid phase of dipolar chains locally arranged in a body-centered-tetragonal order. Significant non-Gaussianity of the energy landscape is responsible for narrowing of the distribution of potential energies and energies of inherent structures with decreasing temperature. We suggest that the proposed functionality of the enumeration function is widely applicable to both polar and nonpolar low-temperature liquids.

  2. Use of infrared thermometry to measure lavage and intravenous fluid temperature.

    PubMed

    Wright, R O; Jay, G D; Becker, B M; Linakis, J G

    1995-05-01

    A study was conducted to determine the accuracy of tympanic thermometers for measuring the temperature of warmed fluids in fluid bags and in tubing at the delivery site (ie, beside the intravenous [IV] catheter). One-liter 0.9% saline bags were warmed in a microwave oven. A thermocouple electronic temperature probe was then used to measure the reference temperature. The probe was inserted into each bag and bathed in the fluid. Temperature changes were recorded simultaneously over a 20-minute period using the probe and a First Temp Tympanic Thermometer (Intelligent Medical Systems, Inc, Carlsbad, CA). The warmed fluid was then allowed to run through microdrip IV tubing. Temperature of the effluent was measured in the tubing using the tympanic thermometer externally and the probe internally at the same point. The two measures were compared using linear regression and Student's t tests. Overall, the correlation between the two probes was r = 0.99 for both the fluid bags and the IV tubing. The overall mean differences were small, 0.7 degrees C and 1.2 degrees C for the bags and tubing, respectively, but they were statistically different (P > .05). Data were analyzed in three temperature ranges: < 36 degrees C, 36 degrees C to 41 degrees C, and 41 degrees C. Again, small differences were found on the order of 1 degree C. It was concluded that infrared thermometry is an accurate method for measuring the initial and delivery temperature of warmed fluids. Although tympanic thermometer measurements were statistically different from reference readings in certain temperature ranges, these differences were small and not clinically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Measurement of temperature and velocity fields in a convective fluid flow in air using schlieren images.

    PubMed

    Martínez-González, A; Moreno-Hernández, D; Guerrero-Viramontes, J A

    2013-08-01

    A convective fluid flow in air could be regulated if the physical process were better understood. Temperature and velocity measurements are required in order to obtain a proper characterization of a convective fluid flow. In this study, we show that a classical schlieren system can be used for simultaneous measurements of temperature and velocity in a convective fluid flow in air. The schlieren technique allows measurement of the average fluid temperature and velocity integrated in the direction of the test beam. Therefore, in our experiments we considered surfaces with isothermal conditions. Temperature measurements are made by relating the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the schlieren system. The same schlieren images were also used to measure the velocity of the fluid flow by using optical flow techniques. The algorithm implemented analyzes motion between consecutive schlieren frames to obtain a tracked sequence and finally velocity fields. The proposed technique was applied to measure the temperature and velocity fields in natural convection of air due to unconfined and confined heated rectangular plates.

  4. 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.

  5. Examination of the phase transition behavior of nano-confined fluids by statistical temperature molecular dynamics.

    PubMed

    Gai, Lili; Iacovella, Christopher R; Wan, Li; McCabe, Clare; Cummings, Peter T

    2015-08-07

    The fluid-solid phase transition behavior of nano-confined Lennard-Jones fluids as a function of temperature and degree of nanoconfinement has been studied via statistical temperature molecular dynamics (STMD). The STMD method allows the direct calculation of the density of states and thus the heat capacity with high efficiency. The fluids are simulated between parallel solid surfaces with varying pore sizes, wall-fluid interaction energies, and registry of the walls. The fluid-solid phase transition behavior has been characterized through determination of the heat capacity. The results show that for pores of ideal-spacing, the order-disorder transition temperature (T(ODT)) is reduced as the pore size increases until values consistent with that seen in a bulk system. Also, as the interaction between the wall and fluid is reduced, T(ODT) is reduced due to weak constraints from the wall. However, for non-ideal spacing pores, quite different behavior is obtained, e.g., generally T(ODT) are largely reduced, and T(ODT) is decreased as the wall constraint becomes larger. For unaligned walls (i.e., whose lattices are not in registry), the fluid-solid transition is also detected as T is reduced, indicating non-ideality in orientation of the walls does not impact the formation of a solid, but results in a slight change in T(ODT) compared to the perfectly aligned systems. The STMD method is demonstrated to be a robust way for probing the phase transitions of nanoconfined fluids systematically, enabling the future examination of the phase transition behavior of more complex fluids.

  6. Effect of Periodic Surface Air Temperature Variations on Subsurface Thermal Structure with Vertical Fluid flow

    NASA Astrophysics Data System (ADS)

    D, R. V.; Ravi, M.; Srivastava, K.

    2016-12-01

    The influence of climate change on near subsurface temperatures is an important research topic for global change impact assessment at the regional scale. The varying temperature of the air over the surface in long term will disturb subsurface thermal structure. Groundwater flow is another important process which perturbs the thermal distribution into the subsurface. To investigate the effect of periodic air temperature on nonisothermal subsurface, one dimensional transient heat conduction-advection equation is solved numerically using finite element method. Thermal response of subsurface for periodic variations in surface air temperature (SAT) with robin type boundary condition on the surface with vertical ground water flow are calculated and the amplitude attenuation of propagation of surface temperature information in the subsurface for different scenarios of advection and convective coefficient are discussed briefly. The results show the coupled response of trigonometric variation in air temperature with surface temperatures along with ground water velocity has significant implications for the effects of climate change.

  7. 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.

  8. Analysis of oil lubricated, fluid film, thrust bearings with allowance for temperature dependent viscosity

    NASA Technical Reports Server (NTRS)

    Pan, C. H. T.; Malanoski, S. B.

    1972-01-01

    A preliminary design study was performed to seek a fluid-film thrust bearing design intended to be part of a high-speed, hybrid (rolling element/fluid film) bearing configuration. The base line used is a design previously tested. To improve the accuracy of theoretical predictions of load capacity, flow rate, and friction power loss, an analytical procedure was developed to include curvature effects inherent in thrust bearings and to allow for the temperature rise in the fluid due to viscous heating. Also, a narrow-groove approximation in the treatment of the temperature field was formulated to apply the procedure to the Whipple thrust bearing. A comparative trade-off study was carried out assuming isothermal films; its results showed the shrouded-step design to be superior to the Whipple design for the intended application. An extensive parametric study was performed, employing isoviscous calculations, to determine the optimized design, which was subsequently recalculated allowing for temperature effects.

  9. SIMPLE METHOD FOR DETECTING ANOMALOUS FLUID MOTIONS IN BOREHOLES FROM CONTINUOUS TEMPERATURE LOGS.

    USGS Publications Warehouse

    Diment, William H.; Urban, Thomas C.

    1983-01-01

    Above a critical Rayleigh number, the fluid in a borehole convects. The aspect ratio of the convective motions is commonly between four and ten as determined by temperature-time recordings at fixed depths in cased holes. Aspect ratios greatly in excess of this range indicate anomalous fluid-flow in the hole such as might be caused by exchange of fluid among aquifers. Such high-aspect ratios can be detected from a single continuous temperature-depth log by taking the difference between the temperature gradient over a short interval and that over a longer spanning interval and dividing this difference by the gradient over the longer interval. This provides a measure of the gradient error (GE) from which an aspect ratio (AR) can be calculated. GEAR logs are presented for a large and a small diameter hole and for a large-diameter partially cased hole containing a small-diameter tubing. Refs.

  10. 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.

  11. Using diffusion MRI for measuring the temperature of cerebrospinal fluid within the lateral ventricles.

    PubMed

    Kozak, L R; Bango, M; Szabo, M; Rudas, G; Vidnyanszky, Z; Nagy, Z

    2010-02-01

    Hypothermia is often induced to reduce brain injury in newborns, following perinatal hypoxic-ischaemic events, and in adults following traumatic brain injury, stroke or cardiac arrest. We aimed to devise a method, based on diffusion-weighted MRI, to measure non-invasively the temperature of the cerebrospinal fluid in the lateral ventricles. The well-known temperature dependence of the water diffusion constant was used for the estimation of temperature. We carried out diffusion MRI measurements on a 3T Philips Achieva Scanner involving phantoms (filled with water or artificial cerebrospinal fluid while slowly cooling from 41 to 32 degrees C) and healthy adult volunteers. The estimated temperature of water phantoms followed that measured using a mercury thermometer, but the estimates for artificial cerebrospinal fluid were 1.04 degrees C lower. After correcting for this systematic difference, the estimated temperature within the lateral ventricles of volunteers was 39.9 degrees C. Using diffusion directions less sensitive to cerebrospinal fluid flow, it was 37.7 degrees C, which was in agreement with the literature. Although further improvements are needed, measuring the temperature within the lateral ventricles using diffusion MRI is a viable method that may be useful for clinical applications. We introduced the method, identified sources of error and offered remedies for each.

  12. Using diffusion MRI for measuring the temperature of cerebrospinal fluid within the lateral ventricles

    PubMed Central

    Kozak, LR; Bango, M; Szabo, M; Rudas, G; Vidnyanszky, Z; Nagy, Z

    2010-01-01

    Aim: Hypothermia is often induced to reduce brain injury in newborns, following perinatal hypoxic–ischaemic events, and in adults following traumatic brain injury, stroke or cardiac arrest. We aimed to devise a method, based on diffusion-weighted MRI, to measure non-invasively the temperature of the cerebrospinal fluid in the lateral ventricles. Methods: The well-known temperature dependence of the water diffusion constant was used for the estimation of temperature. We carried out diffusion MRI measurements on a 3T Philips Achieva Scanner involving phantoms (filled with water or artificial cerebrospinal fluid while slowly cooling from 41 to 32°C) and healthy adult volunteers. Results: The estimated temperature of water phantoms followed that measured using a mercury thermometer, but the estimates for artificial cerebrospinal fluid were 1.04°C lower. After correcting for this systematic difference, the estimated temperature within the lateral ventricles of volunteers was 39.9°C. Using diffusion directions less sensitive to cerebrospinal fluid flow, it was 37.7°C, which was in agreement with the literature. Conclusion: Although further improvements are needed, measuring the temperature within the lateral ventricles using diffusion MRI is a viable method that may be useful for clinical applications. We introduced the method, identified sources of error and offered remedies for each. PMID:19845565

  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. 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.

  15. Monitoring synchrotron X-ray-induced radiolysis effects on metal (Fe, W) ions in high-temperature aqueous fluids.

    PubMed

    Mayanovic, Robert A; Anderson, Alan J; Dharmagunawardhane, Hingure A N; Pascarelli, Sakura; Aquilanti, Giuliana

    2012-09-01

    Radiolysis-induced effects on aqueous tungsten ions are observed to form a precipitate within seconds upon exposure to a synchrotron X-ray micro-beam in a WO(3) + H(2)O system at 873 K and 200 MPa. In situ Fe K-edge energy-dispersive X-ray absorption spectroscopy (ED-XAS) measurements were made on Fe(II)Cl(2) aqueous solutions to 773 K in order to study the kinetics of high-temperature reactions of Fe(2+) and Fe(3+) ions with transient radiolysis species. The radiolytic reactions in a fluid sample within a hydrothermal diamond anvil cell result in oxidation of the Fe(2+) ion at 573 K and reduction of Fe(3+) at temperatures between 673 and 773 K and of the Fe(2+) ion at 773 K. The edge-energy drift evident in the ED-XAS data directly reflects the kinetics of reactions resulting in oxidation and/or reduction of the Fe(2+) and Fe(3+) ions in the aqueous solutions at high temperatures. The oxidation and reduction trends are found to be highly consistent, making reliable determinations of reaction kinetics possible.

  16. 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.

  17. High temperature, short time pasteurization temperatures inversely affect bacterial numbers during refrigerated storage of pasteurized fluid milk.

    PubMed

    Ranieri, M L; Huck, J R; Sonnen, M; Barbano, D M; Boor, K J

    2009-10-01

    The grade A Pasteurized Milk Ordinance specifies minimum processing conditions of 72 degrees C for at least 15 s for high temperature, short time (HTST) pasteurized milk products. Currently, many US milk-processing plants exceed these minimum requirements for fluid milk products. To test the effect of pasteurization temperatures on bacterial numbers in HTST pasteurized milk, 2% fat raw milk was heated to 60 degrees C, homogenized, and treated for 25 s at 1 of 4 different temperatures (72.9, 77.2, 79.9, or 85.2 degrees C) and then held at 6 degrees C for 21 d. Aerobic plate counts were monitored in pasteurized milk samples at d 1, 7, 14, and 21 postprocessing. Bacterial numbers in milk processed at 72.9 degrees C were lower than in milk processed at 85.2 degrees C on each sampling day, indicating that HTST fluid milk-processing temperatures significantly affected bacterial numbers in fluid milk. To assess the microbial ecology of the different milk samples during refrigerated storage, a total of 490 psychrotolerant endospore-forming bacteria were identified using DNA sequence-based subtyping methods. Regardless of processing temperature, >85% of the isolates characterized at d 0, 1, and 7 postprocessing were of the genus Bacillus, whereas more than 92% of isolates characterized at d 14 and 21 postprocessing were of the genus Paenibacillus, indicating that the predominant genera present in HTST-processed milk shifted from Bacillus spp. to Paenibacillus spp. during refrigerated storage. In summary, 1) HTST processing temperatures affected bacterial numbers in refrigerated milk, with higher bacterial numbers in milk processed at higher temperatures; 2) no significant association was observed between genus isolated and pasteurization temperature, suggesting that the genera were not differentially affected by the different processing temperatures; and 3) although typically present at low numbers in raw milk, Paenibacillus spp. are capable of growing to numbers that can

  18. Transient absorption probe of intermolecular triplet excimer of naphthalene in fluid solutions: Identification of the species based on comparison to the intramolecular triplet excimers of covalently-linked dimers

    SciTech Connect

    Wang, X.; Kofron, W.G.; Kong, S.; Rajesh, C.S.; Modarelli, D.A.; Lim, E.C.

    2000-02-24

    The authors report here the observation of the laser-induced transient absorption spectrum of intermolecular triplet excimers of naphthalene in fluid solution. This assignment is confirmed by comparison to the transient absorption spectra of the intramolecular triplet excimers of covalently linked dimers of naphthalene and quinoxaline.

  19. 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.

  20. Voluntary fluid intake and core temperature responses in adolescent tennis players: sports beverage versus water

    PubMed Central

    Bergeron, M F; Waller, J L; Marinik, E L

    2006-01-01

    Objective To examine differences in ad libitum fluid intake, comparing a 6% carbohydrate/electrolyte drink (CHO‐E) and water, and associated differences in core temperature and other selected physiological and perceptual responses in adolescent athletes during tennis training in the heat. Methods Fourteen healthy, fit, young tennis players (nine male; five female; mean (SD) age 15.1 (1.4) years; weight 60.6 (8.3) kg; height 172.8 (8.6) cm) completed two 120 minute tennis specific training sessions on separate days (randomised, crossover design) in a warm environment (wet bulb globe temperature: CHO‐E, 79.3 (2.6) °F; water, 79.9 (2.2) °F; p>0.05). Results There were no significant differences (p>0.05) between the trials with respect to fluid intake, urine volume, fluid retention, sweat loss, perceived exertion, thirst, or gastrointestinal discomfort. However, there was a difference (p<0.05) in the percentage body weight change after training (CHO‐E, −0.5 (0.7)%; water, −0.9 (0.6)%). Urine specific gravity before training (CHO‐E, 1.024 (0.006); water, 1.025 (0.005)) did not correlate significantly (p>0.05) with any of these measurements or with core body temperature. In examining the main effect for trial, the CHO‐E trial showed a significantly lower (p<0.001) mean body temperature (irrespective of measurement time) than the water trial. However, the mean body temperature in each trial was not associated (p>0.05) with fluid intake, fluid retention, sweat loss, or percentage body weight change. Conclusion Ad libitum consumption of a CHO‐E drink may be more effective than water in minimising fluid deficits and mean core temperature responses during tennis and other similar training in adolescent athletes. PMID:16632570

  1. Voluntary fluid intake and core temperature responses in adolescent tennis players: sports beverage versus water.

    PubMed

    Bergeron, M F; Waller, J L; Marinik, E L

    2006-05-01

    To examine differences in ad libitum fluid intake, comparing a 6% carbohydrate/electrolyte drink (CHO-E) and water, and associated differences in core temperature and other selected physiological and perceptual responses in adolescent athletes during tennis training in the heat. Fourteen healthy, fit, young tennis players (nine male; five female; mean (SD) age 15.1 (1.4) years; weight 60.6 (8.3) kg; height 172.8 (8.6) cm) completed two 120 minute tennis specific training sessions on separate days (randomised, crossover design) in a warm environment (wet bulb globe temperature: CHO-E, 79.3 (2.6) degrees F; water, 79.9 (2.2) degrees F; p>0.05). There were no significant differences (p>0.05) between the trials with respect to fluid intake, urine volume, fluid retention, sweat loss, perceived exertion, thirst, or gastrointestinal discomfort. However, there was a difference (p<0.05) in the percentage body weight change after training (CHO-E, -0.5 (0.7)%; water, -0.9 (0.6)%). Urine specific gravity before training (CHO-E, 1.024 (0.006); water, 1.025 (0.005)) did not correlate significantly (p>0.05) with any of these measurements or with core body temperature. In examining the main effect for trial, the CHO-E trial showed a significantly lower (p<0.001) mean body temperature (irrespective of measurement time) than the water trial. However, the mean body temperature in each trial was not associated (p>0.05) with fluid intake, fluid retention, sweat loss, or percentage body weight change. Ad libitum consumption of a CHO-E drink may be more effective than water in minimising fluid deficits and mean core temperature responses during tennis and other similar training in adolescent athletes.

  2. Localized heating on silicon field effect transistors: device fabrication and temperature measurements in fluid.

    PubMed

    Elibol, Oguz H; Reddy, Bobby; Nair, Pradeep R; Dorvel, Brian; Butler, Felice; Ahsan, Zahab S; Bergstrom, Donald E; Alam, Muhammad A; Bashir, Rashid

    2009-10-07

    We demonstrate electrically addressable localized heating in fluid at the dielectric surface of silicon-on-insulator field-effect transistors via radio-frequency Joule heating of mobile ions in the Debye layer. Measurement of fluid temperatures in close vicinity to surfaces poses a challenge due to the localized nature of the temperature profile. To address this, we developed a localized thermometry technique based on the fluorescence decay rate of covalently attached fluorophores to extract the temperature within 2 nm of any oxide surface. We demonstrate precise spatial control of voltage dependent temperature profiles on the transistor surfaces. Our results introduce a new dimension to present sensing systems by enabling dual purpose silicon transistor-heaters that serve both as field effect sensors as well as temperature controllers that could perform localized bio-chemical reactions in Lab on Chip applications.

  3. Localized Heating on Silicon Field Effect Transistors: Device Fabrication and Temperature Measurements in Fluid

    PubMed Central

    Elibol, Oguz H.; Reddy, Bobby; Nair, Pradeep R.; Dorvel, Brian; Butler, Felice; Ahsan, Zahab; Bergstrom, Donald E.; Alam, Muhammad A.; Bashir, Rashid

    2010-01-01

    We demonstrate electrically addressable localized heating in fluid at the dielectric surface of silicon-on-insulator field-effect transistors via radio-frequency Joule heating of mobile ions in the Debye layer. Measurement of fluid temperatures in close vicinity to surfaces poses a challenge due to the localized nature of the temperature profile. To address this, we developed a localized thermometry technique based on the fluorescence decay rate of covalently attached fluorophores to extract the temperature within 2 nm of any oxide surface. We demonstrate precise spatial control of voltage dependent temperature profiles on the transistor surfaces. Our results introduce a new dimension to present sensing systems by enabling dual purpose silicon transistor-heaters that serve both as field effect sensors as well as temperature controllers that could perform localized bio-chemical reactions in Lab on Chip applications. PMID:19967115

  4. Monopolar radiofrequency use in deep gluteal space endoscopy: sciatic nerve safety and fluid temperature.

    PubMed

    Martin, Hal David; Palmer, Ian James; Hatem, Munif

    2014-01-01

    The purpose of this study was to evaluate the temperature at the sciatic nerve when using a monopolar radiofrequency (RF) probe to control bleeding in deep gluteal space endoscopy, as well as assess the fluid temperature profile. Ten hips in 5 fresh-frozen human cadaveric specimens from the abdomen to the toes were used for this experiment. Temperatures were measured at the sciatic nerve after 2, 5, and 10 seconds of continuous RF probe activation over an adjacent vessel, a branch of the inferior gluteal artery. Fluid temperatures were then measured at different distances from the probe (3, 5, and 10 mm) after 2, 5, and 10 seconds of continuous probe activation. All tests were performed with irrigation fluid flow at 60 mm Hg allowing outflow. After 2, 5, or 10 seconds of activation over the crossing branch of the inferior gluteal artery, the mean temperature increased by less than 1°C on the surface and in the perineurium of the sciatic nerve. Considering the fluid temperature profile in the deep gluteal space, the distance and duration of activation influenced temperature (P < .05). Continuous delivery of RF energy for 10 seconds caused fluid temperature increases of 1.2°C, 2°C, and 3.1°C on average at 10 mm, 5 mm, and 3 mm of distance, respectively. This study found the tested monopolar RF device to be safe during use in vessels around the sciatic nerve after 2, 5, and 10 seconds of continuous activation. The maximum fluid temperature (28°C) after 10 seconds of activation at 3 mm of distance is lower than the minimal reported temperature necessary to cause nerve changes (40°C to 45°C). Monopolar RF seems to be safe to the neural structures when used at more than 3 mm of distance and with less than 10 seconds of continuous activation in deep gluteal space endoscopy with fluid inflow and outflow. Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. Temperature gradients drive radial fluid flow in Petri dishes and multiwell plates.

    PubMed

    Lindsay, Stephen M; Yin, John

    2016-06-01

    Liquid in a Petri dish spontaneously circulates in a radial pattern, even when the dish is at rest. These fluid flows have been observed and utilized for biological research, but their origins have not been well-studied. Here we used particle-tracking to measure velocities of radial fluid flows, which are shown to be linked to evaporation. Infrared thermal imaging was used to identify thermal gradients at the air-liquid interface and at the bottom of the dish. Two-color ratiometric fluorescence confocal imaging was used to measure thermal gradients in the vertical direction within the fluid. A finite-element model of the fluid, incorporating the measured temperature profiles, shows that buoyancy forces are sufficient to produce flows consistent with the measured particle velocity results. Such flows may arise in other dish or plate formats, and may impact biological research in positive or negative ways.

  11. 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.

  12. Effect of storage time and temperature on the results of analysis of synovial and mesothelial fluids.

    PubMed

    Hughes, K J; Rendle, D I; Higgins, S; Barron, R; Cowling, A; Love, S; Durham, A E

    2017-03-01

    Delays between collection and laboratory analysis of equine body fluid samples are common in practice; however, the effects of delays on the accuracy of results and diagnostic interpretation are unknown. To assess the effects of storage time and temperature combination on protein and cell parameters of equine synovial and mesothelial cavity fluids and determine whether any changes affect clinicopathological interpretation. In vitro experiment. Body fluid samples obtained from horses during diagnostic investigation were divided into 7 aliquots and total protein concentration (TP), total nucleated cell count (TNCC) and neutrophil morphology were analysed immediately (T0 ) and at 24 (T24 ), 48 (T48 ) and 72 h (T72 ) after storage at 4 or 22°C. Linear mixed models were used to analyse effects of fluid type and storage conditions on TP, TNCC and neutrophil morphology grade. Changes in interpretation of samples over time and diagnostic performance at each analysis point were recorded. A total of 32 samples were collected from 23 horses. Storage had no effect on TP. Cell count was influenced by fluid type and was significantly reduced at T72 for storage at 4°C and T24 , T48 and T72 for 22°C (P<0.001). Neutrophil morphology grade was significantly greater at T24 , T48 and T72 than at T0 for both 4 and 22°C (P<0.001). For 9 samples, the diagnostic interpretation changed over time. Specificity and positive predictive value at each analysis point was 100%; however, sensitivity and negative predictive value decreased with greater storage duration and temperature. Alterations in the TNCC and neutrophil morphology of body fluid samples occur when analysis is delayed, especially with higher storage temperatures, and may influence interpretation and clinical decision-making. Body fluid samples should be analysed as soon as possible after collection to minimise preanalytical errors due to storage. © 2016 EVJ Ltd.

  13. A semi-analytical approach to the study of an elastic circular cylinder confined in a cylindrical fluid domain subjected to small-amplitude transient motions

    NASA Astrophysics Data System (ADS)

    Leblond, C.; Sigrist, J. F.; Auvity, B.; Peerhossaini, H.

    2009-01-01

    This paper deals with the transient motions experienced by an elastic circular cylinder in a cylindrical fluid domain initially at rest and subjected to small-amplitude imposed displacements. Three fluid models are considered, namely potential, viscous and acoustic, to cover different fluid-structure interaction regimes. They are derived here from the general compressible Navier-Stokes equations by a formal perturbation method so as to underline their links and ranges of validity a priori. The resulting fluid models are linear owing to the small-amplitude-displacement hypothesis. For simplicity, the elastic flexure beam model is chosen for the circular cylinder dynamics. The semi-analytical approach used here is based on the methods of Laplace transform in time, in vacuo eigenvector expansion with time-dependent coefficients for the transverse beam displacement and separation of variables for the fluid. Moreover, the viscous case is handled with a matched asymptotic expansion performed at first order. The projection of the fluid forces on the in vacuo eigenvectors leads to a fully coupled system involving the modal time-dependent displacement coefficients. These coefficients are then obtained by matrix inversion in the Laplace domain and fast numerical inversion of the Laplace transform. The three models, written in the form of convolution products, are described through the analysis of their kernels, involving both the wave propagation phenomena in the fluid domain and the beam elasticity. Last, the three models are illustrated for a specific imposed motion mimicking shock loading. It is shown that their combination permits coverage of a broad range of motions.

  14. 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.

  15. 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.

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

    SciTech Connect

    Etters, R.D.

    1992-03-01

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

  17. 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

    2017-01-01

    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.

  18. Does prehospital fluid administration impact core body temperature and coagulation functions in combat casualties?

    PubMed

    Farkash, Uri; Lynn, Mauricio; Scope, Alon; Maor, Ron; Turchin, Nickolai; Sverdlik, Borris; Eldad, Arieh

    2002-03-01

    Administration of large amounts of fluids to trauma patients, in the absence of surgical control, may increase bleeding, cause hypothermia and coagulopathy which may worsen the bleeding and increase morbidity and mortality. The purpose of our study is to examine the impact of prehospital fluid administration to military combat casualties on core body temperature and coagulation functions. Prospective data were collected on all cases of moderately (9 < or = ISS < or = 14) and severely (ISS > or = 16) injured victims wounded in South Lebanon, treated by Israeli military physicians and evacuated to hospitals in Israel, over a two-year period. Data regarding prehospital phase of injury (timetables, amount of fluids) and upon hospital arrival (initial core body temperature, prothrombin time [PT], partial thromboplastin time [PTT]) were examined for monotonic relation using Spearman's non-parametric test. Fifty-three moderately injured and 31 severely injured patients were included in the study. The average evacuation time for the moderately injured group was 109.3 +/- 44.8 min, and for the severely injured 100.3 +/- 38.4 min (P value=NS). The mean volume of fluids administered was 2.39 +/- 1.52 and 2.49 +/- 1.47 l, respectively (P=NS). No statistical correlation was found between core body temperature, PT or PTT, measured upon hospital arrival, and prehospital fluid treatment. In addition, no correlation was found between core body temperature on hospital arrival and prehospital time, or between prehospital fluid volumes and prehospital time. The mean core body temperature of the moderately injured patients was 36.8 degrees C, and that of severely injured was 35.8 degrees C (P=0.026). With proper control of blood loss and avoidance of excessive fluid administration, moderately and severely injured combat casualties in 'low intensity conflict' in South Lebanon can be resuscitated with fluid volumes that do not result in a coagulation deficit or hypothermia. The core body

  19. 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.

  20. 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.

  1. A Comparative Study of the Effect of Surfactant and Temperature in Fluid Interfaces

    NASA Astrophysics Data System (ADS)

    Cortes-Estrada, Aldo H.; Ibarra-Bracamontes, Laura A.; Aguilar-Corona, Alicia; Viramontes-Gamboa, Gonzalo

    2016-11-01

    A fluid interface is the boundary region formed when two immiscible fluids come into contact. One of the most important properties of fluid interfaces is the interfacial tension. The interfacial tension between two fluids can be modified by the presence of surfactant. In addition, the temperature is a relevant factor that can also modify the interfacial properties. In this work the behavior of the interface formed by oil and water in the presence of surfactant at different temperatures is presented. Interfacial tension measurements were obtained by the Pendant Drop technique. Two types of surfactant were tested, Sodium Dodecyl Sulfate (SDS) as a hydrophilic surfactant, and Sorbitan Monooleate (Span 80) as a lipophilic surfactant. The range of variations in temperature was from 25 to 60 Celsius degree. Hexane or Dodecane was used as the oil phase. The main results showed that the lipophilic surfactant showed a greater efficiency with respect to the hydrophilic surfactant used. As the temperature increased in the range considered an exponential decay for the interfacial tension was observed. This decay was dominated by the surfactant concentration. This study was supported by the Mexican Council of Science and Technology (CONACyT) and by the Scientific Research Coordination of the University of Michoacan in Mexico.

  2. 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.

  3. 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.

  4. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Temperature-induced changes in soft tissues analyzed by spectral methods and transient elastography: A comparative study

    NASA Astrophysics Data System (ADS)

    Cortela, G. A.; Benech, N.; Pereira, W. C. A.; Negreira, C.

    2012-05-01

    Some biological tissues, such as skeletal muscle, have regular or quasi-periodic structures. Periodicity of these structures can be investigated by spectral methods based on ultrasonic backscattered signals. These methods estimate the Mean Scatterer Spacing (MSS). In this work we analyzed the MSS dependence with temperature in bovine skeletal muscle tissue samples. Through spectral analysis we found that the relative variation of the MSS, in the temperature range 20 - 48°C was of ~ 2% /°C. For the same sample and under the same experimental conditions, we analyzed the propagation velocity of shear waves by transient elastography. It was determined that the relative variation of shear elastic modulus was ~ 3% /°C in the same temperature range. The repeatability of the results was tested in three tissue samples, with a set of 6 measurements on each. The relative variation is therefore similar for both parameters. Thus, this study shows that both techniques can be used as a method of noninvasive thermometry for small temperature range. In addition we emphasize the conceptual differences between both methods. As temperature changes, MSS estimation varies due to two physical phenomena. An apparent variation in mean spacing is produced because the sound speed is temperature-dependent, while tissue expansion produces a real change. In practice it is difficult to discriminate the weight of each component in the MSS variation. On the other side, transient elastography is less sensitive to thermal expansion. Thus it measures the actual shear wave speed change with temperature. This differentiation between both methods could be used to construct useful thermoelastic models for soft tissues in the future.

  6. 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

  7. Water temperature, voluntary drinking and fluid balance in dehydrated taekwondo athletes.

    PubMed

    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 pointsFor 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.

  8. 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.

  9. Towards adaptive kinetic-fluid simulations of low-temperature plasmas

    NASA Astrophysics Data System (ADS)

    Kolobov, Vladimir

    2013-09-01

    The emergence of new types of gaseous electronics in multi-phase systems calls for computational tools with adaptive kinetic-fluid simulation capabilities. We will present an Adaptive Mesh and Algorithm Refinement (AMAR) methodology for multi-scale simulations of gas flows and discuss current efforts towards extending this methodology for weakly ionized plasmas. The AMAR method combines Adaptive Mesh Refinement (AMR) with automatic selection of kinetic or fluid solvers in different parts of computational domains. This AMAR methodology was implemented in our Unified Flow Solver (UFS) for mixed rarefied and continuum flows. UFS uses discrete velocity method for solving Boltzmann kinetic equation under rarefied flow conditions coupled to fluid (Navier-Stokes) solvers for continuum flow regimes. The main challenge of extending AMAR to plasmas comes from the distinction of electron and atom mass. We will present multi-fluid, two-temperature plasma models with AMR capabilities for simulations of glow, corona, and streamer discharges. We will briefly discuss specifics of electron kinetics in collisional plasmas, and deterministic methods of solving kinetic equations for different electron groups. Kinetic solvers with Adaptive Mesh in Phase Space (AMPS) will be introduced to solve Boltzmann equation for electrons in the presence of electric fields, elastic and inelastic collisions with atoms. These kinetic and fluid models are currently being incorporated into AMAR methodology for multi-scale simulations of low-temperature plasmas in multi-phase systems. Supported by AFOSR, NASA, and DoE

  10. Nonlinear stresses and temperatures in transient adiabatic and shear flows via nonequilibrium molecular dynamics: Three definitions of temperature

    NASA Astrophysics Data System (ADS)

    Hoover, Wm. G.; Hoover, C. G.

    2009-04-01

    We compare nonlinear stresses and temperatures for adiabatic-shear flows, using up to 262 144 particles, with those from corresponding homogeneous and inhomogeneous flows. Two varieties of kinetic temperature tensors are compared to the configurational temperatures. This comparison of temperatures led us to two findings beyond our original goal of analyzing shear algorithms. First, we found an improved form for local instantaneous velocity fluctuations, as calculated with smooth-particle weighting functions. Second, we came upon the previously unrecognized contribution of rotation to the configurational temperature.

  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. 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.

  13. 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.

  14. Global analysis of the effect of fluid flow on subduction zone temperatures

    NASA Astrophysics Data System (ADS)

    Rotman, Holly M. M.; Spinelli, Glenn A.

    2013-08-01

    Knowledge of the controls on temperature distributions at subduction zones is critical for understanding a wide range of seismic, metamorphic, and magmatic processes. Here, we present the results of ˜220 thermal model simulations covering the majority of known subduction zone convergence rates, incoming plate ages, and slab dips. We quantify the thermal effects of fluid circulation in the subducting crust by comparing results with and without advective heat transfer in the oceanic crustal aquifer. We find that hydrothermal cooling of a subduction zone is maximized when the subducting slab is young, slowly converging, steeply dipping, and the crustal aquifer is ventilated near the trench. Incoming plate age is one of the primary controls on the effectiveness of advective heat transfer in the aquifer, and the greatest temperature effects occur with an incoming plate <50 Ma. The thermal effects of fluid circulation decrease dramatically with increasing age of the incoming plate. Temperatures in the Cascadia, Nankai, southern Chile, Colombia/Ecuador, Mexico, and Solomon Islands subduction zones are likely strongly affected by fluid circulation; for these systems, only thermal models of Cascadia and Nankai have included fluid flow in subducting crust.

  15. 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.

  16. 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.

  17. 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

  18. Relationship between recent cave temperatures and noble gas temperatures derived from fluid inclusions of modern soda straw stalactites

    NASA Astrophysics Data System (ADS)

    Palcsu, Laszlo; Papp, Laszlo; Major, Zoltan; Molnar, Mihaly

    2010-05-01

    Recently, strong effort is devoted to establish a new method to derive palaeotemperatures from noble gas (Ne, Ar, Kr, Xe) concentrations dissolved in fluid inclusions of speleothems [1-2]. It has been already shown that the water content of the speleothems can be determined via the water vapour pressure after the water has been released from the carbonate samples and collected in a cold finger and then heated up to room temperature. Additionally, the noble gas contents can be precisely measured with noble gas mass spectrometers. Based on these noble gas concentration data sets, a so-called noble gas temperature (NGT) can be calculated meaning a temperature at which the noble gases have been dissolved in water. To use these NGT's as a palaeoclimate proxy, one of the main questions is how these noble gas temperatures reflect the prevailing cave temperature in which the carbonate has grown. We studied noble gas significances in recent soda straw stalactites from more than ten Central European caves covering a temperature range of 1 to 14 °C. Kluge et al. (2008) has shown the soda straw stalactites might contain less excess air, hence they are more suitable samples to derive NGT's, because noble gas abundances from large air inclusions can mask the temperature information. The 14C ages of these soda straw dripstones were obtained to be recent or at least Holocene ages. Thus one can assume that the cave temperatures during carbonate formation were as same as at present. We measured the water and noble gas contents of numerous carbonate samples from soda straw stalactites and calculated noble gas temperatures by a precision of 1 °C or better. Comparing these temperatures with cave temperatures we obtained that they agree well within the uncertainty of the noble gas temperature determination. Therefore, we can conclude if diffusion of noble gas isotopes does not play a significant role in the carbonate lattice this new tool helps the palaeoclimate community to gain

  19. 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

  20. On transient-flows of the Ostwald-de Waele fluids-transport in the Darcy-Brinkman porous medium

    NASA Astrophysics Data System (ADS)

    Siddiqui, Abuzar Abid

    2017-07-01

    This paper presents the mathematical formulation of the pulsatile motion of an Ostwald-de Waele (OdW) fluid in the circular-annular duct and the rectangular channel filled with the Darcy-Brinkman porous material/medium. The Ostwald-de Waele fluid model, modified for the Darcy-Brinkman medium, is used to get the boundary value problems (BVPs). These BVPs contain non-linear partial differential equations (PDEs). These PDEs are further transformed to the ordinary differential equations (ODEs) on using the pulsatile-transformation. The ODEs are solved numerically for different values of OdW-index. However, the exact solutions are also derived for one of the shear-thickening fluids (e.g., p = 2) and the Newtonian fluids (p = 1) in order to validate the numerical results. The numerical results are also compared with the existing or present-derived-analytical solution for the Newtonian fluids. It is observed that the porosity, the permeability and the frequency influence on the fluid-speed, the discharge and the stresses. The fact of relation of the permeability to the porosity is not only valid for the Darcian but also for the Darcy-Brinkman medium. The permeability decreases as the porosity decreases only for shear thinning fluids (p < 1). The imposed pulsatile pressure-gradient results the oscillatory ambient fluid-flow for both the geometries (circular-annular duct and rectangular channel). The radial normal stress is dominant in annular duct whereas the shear stress is significant in rectangular channel.

  1. Non-invasive, transient determination of the core temperature of a heat-generating solid body

    NASA Astrophysics Data System (ADS)

    Anthony, Dean; Sarkar, Daipayan; Jain, Ankur

    2016-11-01

    While temperature on the surface of a heat-generating solid body can be easily measured using a variety of methods, very few techniques exist for non-invasively measuring the temperature inside the solid body as a function of time. Measurement of internal temperature is very desirable since measurement of just the surface temperature gives no indication of temperature inside the body, and system performance and safety is governed primarily by the highest temperature, encountered usually at the core of the body. This paper presents a technique to non-invasively determine the internal temperature based on the theoretical relationship between the core temperature and surface temperature distribution on the outside of a heat-generating solid body as functions of time. Experiments using infrared thermography of the outside surface of a thermal test cell in a variety of heating and cooling conditions demonstrate good agreement of the predicted core temperature as a function of time with actual core temperature measurement using an embedded thermocouple. This paper demonstrates a capability to thermally probe inside solid bodies in a non-invasive fashion. This directly benefits the accurate performance prediction and control of a variety of engineering systems where the time-varying core temperature plays a key role.

  2. Non-invasive, transient determination of the core temperature of a heat-generating solid body.

    PubMed

    Anthony, Dean; Sarkar, Daipayan; Jain, Ankur

    2016-11-02

    While temperature on the surface of a heat-generating solid body can be easily measured using a variety of methods, very few techniques exist for non-invasively measuring the temperature inside the solid body as a function of time. Measurement of internal temperature is very desirable since measurement of just the surface temperature gives no indication of temperature inside the body, and system performance and safety is governed primarily by the highest temperature, encountered usually at the core of the body. This paper presents a technique to non-invasively determine the internal temperature based on the theoretical relationship between the core temperature and surface temperature distribution on the outside of a heat-generating solid body as functions of time. Experiments using infrared thermography of the outside surface of a thermal test cell in a variety of heating and cooling conditions demonstrate good agreement of the predicted core temperature as a function of time with actual core temperature measurement using an embedded thermocouple. This paper demonstrates a capability to thermally probe inside solid bodies in a non-invasive fashion. This directly benefits the accurate performance prediction and control of a variety of engineering systems where the time-varying core temperature plays a key role.

  3. Non-invasive, transient determination of the core temperature of a heat-generating solid body

    PubMed Central

    Anthony, Dean; Sarkar, Daipayan; Jain, Ankur

    2016-01-01

    While temperature on the surface of a heat-generating solid body can be easily measured using a variety of methods, very few techniques exist for non-invasively measuring the temperature inside the solid body as a function of time. Measurement of internal temperature is very desirable since measurement of just the surface temperature gives no indication of temperature inside the body, and system performance and safety is governed primarily by the highest temperature, encountered usually at the core of the body. This paper presents a technique to non-invasively determine the internal temperature based on the theoretical relationship between the core temperature and surface temperature distribution on the outside of a heat-generating solid body as functions of time. Experiments using infrared thermography of the outside surface of a thermal test cell in a variety of heating and cooling conditions demonstrate good agreement of the predicted core temperature as a function of time with actual core temperature measurement using an embedded thermocouple. This paper demonstrates a capability to thermally probe inside solid bodies in a non-invasive fashion. This directly benefits the accurate performance prediction and control of a variety of engineering systems where the time-varying core temperature plays a key role. PMID:27804981

  4. Detection and Quantification of Local Anthropogenic and Regional Climatic Transient Signals in Temperature Logs from Czechia and Slovenia

    NASA Astrophysics Data System (ADS)

    Dědeček, P.; Šafanda, J.; Rajver, D.

    2012-04-01

    The presentation focuses on detection and quantification of the impact of local anthropogenic structures and regional climatic changes on subsurface temperature field. The analyzed temperature records were obtained by temperature monitoring in a borehole in Prague-Spořilov (Czechia) and by repeated logging of a borehole in Šempeter (Slovenia). The observed data were compared with temperatures yielded by mathematical 3D time-variable geothermal models of the boreholes' sites with the aim to decompose the observed transient component of the subsurface temperature into the part affected by construction of new buildings and other anthropogenic structures in surroundings of the boreholes and into the part affected by the ground surface temperature warming due to the surface air temperature rise. A direct human impact on the subsurface temperature warming was proved and contributions of individual anthropogenic structures to this change were evaluated. In the case of Spořilov, where the mean annual warming rate reached 0.034°C per year at the depth of 38.3 m during the period 1993-2008, it turned out that about half of the observed warming can be attributed to the air (ground) surface temperature change and half to the human activity on the surface in the immediate vicinity of the borehole. The situation is similar in Šempeter, where the effect of the recently built surface anthropogenic structures is detectable down to the depth of 80 m and the share of the anthropogenic signal on the non-stationary component of the observed subsurface temperature amounts to 30% at the depth of 50 m.

  5. 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.

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

    PubMed

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

    2013-10-07

    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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

  10. Effect of warm intravenous and irrigating fluids on body temperature during transurethral resection of the prostate gland.

    PubMed

    Okeke, L I

    2007-09-18

    Transurethral resection of the prostate gland with irrigation fluid at room temperature leads to perioperative hypothermia which could give rise to adverse cardiovascular events in the perioperative period. The use of isothermic irrigation fluid reduces but does not eliminate this risk. Routine use of warm intravenous fluids along with isothermic irrigation had not been documented. This study set out to investigate the effect of the use of warm intravenous fluid together with isothermic irrigation fluid on the body temperature in patients undergoing transurethral resection of the prostate gland. One hundred and twenty consented patients with obstructing benign prostatic hyperplasia were randomly assigned to one of 3 groups. Group 1 received irrigation and intravenous fluids at room temperature, group 2 received warmed irrigation fluid at 38 degrees C along with intravenous fluid at room temperature while group 3 patients received warmed irrigation fluid and warmed intravenous fluids at 38 degrees C. Their perioperative body temperature changes were monitored, analyzed and compared. The mean decrease in body temperature at the end of the procedure was significantly greater in group 1 (0.98 +/- 0.56 degrees C) than in group 2 (0.42 +/- .21 degrees C) (p < 0.001). Significantly more patients in group 1 also experienced shivering. However, in group 3, there was no significant change in the mean body temperature (p > 0.05) and none of them felt cold or shivered. It is concluded that the use of isothermic irrigation fluid together with warm intravenous fluids during TURP prevents the occurrence of perioperative hypothermia.

  11. Measured vs. Simulated Transients of Temperature Logs - A Test of Borehole Climatology

    NASA Astrophysics Data System (ADS)

    Majorowicz, J.; Skinner, W.; Gosnold, W.; Safanda, J.

    2005-12-01

    Twenty-seven temperature-depth (T-z) profiles from shallow boreholes of less than 250 m in depth in mostly arid areas of the Canadian Prairie Provinces and northern U.S.A. Great Plains initially measured in the 1980's and early 1990's and repeated in the years 1995, 1999, 2000, 2004 and 2005 are compared with synthetic profiles based on the surface air temperature time series at nearby meteorological stations. Similar comparisons are currently being made for the northern U.S.A. Great Plains. The multiple T-z profiles of southwestern Canadian boreholes indicate a general agreement between ground surface temperature (GST) warming and warming observed in surface air temperature (SAT) series from meteorological stations. GST temperature changes of 0.1 - 0.2° C and 0.4° C are observed between the measurements for the shorter (decade) and longer (two decades) time spans, respectively. Temperature changes for the last 200 years derived from the FSI inversion of the deeper logs in southern Saskatchewan and southern-central Alberta in Canada are 2.5° C. These changes correspond to those changes derived from synthetic profiles in which surface temperature time series are used as forcing signals. Repeated measurements in the U.S.A. northern Great Plains (North Dakota) show similar large relative temperature change as do the Saskatchewan wells. The comparison of changes from repeated temperature logs in the high warming areas of the Canadian Prairies and U.S.A. Great Plains with those simulated from SAT forcing shows that surface temperature forcing is responsible for the majority of the observed deviation of temperature with depth. In some cases however, differences higher than the error of measurements are observed between the model based on surface temperature forcing and observation. These are interpreted in terms of well hydrogeological conditions and the influence of snow cover.

  12. 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.

  13. 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.

  14. A variable temperature student refractometer for the study of fluids in the liquid and frozen state

    NASA Astrophysics Data System (ADS)

    Lau, W. Travis; Minc, Samantha; Tobin, R. G.

    2001-11-01

    While refractive index measurements of transparent fluids and solids are routine, there have been relatively few such measurements on fluids in their frozen state. We have designed and built a simple device to measure the refractive index of frozen liquids. It consists of a trapezoidal prism cell housed in a small vacuum chamber. The cell can be filled with a liquid and cooled to temperatures below -100°C. By measuring the deflection of a He:Ne laser beam as it passes through the cell, we can determine the index of refraction of the fluid to an accuracy of ±0.005 and monitor changes as the fluid is frozen. This versatile system can accurately measure the refractive index of many common transparent fluids, and provides excellent student training in optics, vacuum techniques and error analysis. Measurements in the frozen state are much more challenging because of the difficulty of obtaining clear crystals. We are able to obtain uniformly clear crystals of water ice by cooling the sample slowly while bubbling nitrogen gas through the liquid, and observed the change in refractive index on crystallization.

  15. Transient Receptor Potential-Like Channels Are Essential for Calcium Signaling and Fluid Transport in a Drosophila Epithelium

    PubMed Central

    MacPherson, Matthew R.; Pollock, Valerie P.; Kean, Laura; Southall, Tony D.; Giannakou, Maria E.; Broderick, Kate E.; Dow, Julian A. T.; Hardie, Roger C.; Davies, Shireen A.

    2005-01-01

    Calcium signaling is an important mediator of neuropeptide-stimulated fluid transport by Drosophila Malpighian (renal) tubules. We demonstrate the first epithelial role, in vivo, for members of the TRP family of calcium channels. RT-PCR revealed expression of trp, trpl, and trpγ in tubules. Use of antipeptide polyclonal antibodies for TRP, TRPL, and TRPγ showed expression of all three channels in type 1 (principal) cells in the tubule main segment. Neuropeptide (CAP2b)-stimulated fluid transport rates were significantly reduced in tubules from the trpl302 mutant and the trpl;trp double mutant, trpl302;trp343. However, a trp null, trp343, had no impact on stimulated fluid transport. Measurement of cytosolic calcium concentrations ([Ca2+]i) in tubule principal cells using an aequorin transgene in trp and trpl mutants showed a reduction in calcium responses in trpl302. Western blotting of tubule preparations from trp and trpl mutants revealed a correlation between TRPL levels and CAP2b-stimulated fluid transport and calcium signaling. Rescue of trpl302 with a trpl transgene under heat-shock control resulted in a stimulated fluid transport phenotype that was indistinguishable from wild-type tubules. Furthermore, restoration of normal stimulated rates of fluid transport by rescue of trpl302 was not compromised by introduction of the trp null, trp343. Thus, in an epithelial context, TRPL is sufficient for wild-type responses. Finally, a scaffolding component of the TRPL/TRP-signaling complex, INAD, is not expressed in tubules, suggesting that inaD is not essential for TRPL/TRP function in Drosophila tubules. PMID:15695363

  16. 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

  17. 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.

  18. Determination of shelf heat transfer coefficients along the shelf flow path of a freeze dryer using the shelf fluid temperature perturbation approach.

    PubMed

    Kuu, Wei Y; Nail, Steven L; Hardwick, Lisa M

    2007-01-01

    The spatial distribution of local shelf heat transfer coefficients, Ks, was determined by mapping the transient temperature response of the shelf surface along the serpentine internal channels of the shelf while the temperature of the heat transfer fluid was ramped from -40 degrees to 40 degrees C. The solution of a first-order non-steady-state differential equation resulted in a predicted shelf surface temperature as a function of the shelf fluid temperature at any point along the flow path. During the study, the shelf surfaces were maintained under a thermally insulated condition so that the heat transfers by gas conduction and radiation were negligible. To minimize heat conduction by gas, the chamber was evacuated to a low pressure, such as 100 mTorr. To minimize heat transfers between shelves, shelves were moved close together, with a gap of approximately 3 mm between any two shelves, because the shelf surface temperatures at corresponding vertical locations of two shelves are virtually equal. In addition, this also provides a shielding from radiation heat transfer from shelf to walls. Local heat transfer coefficients at the probed locations h(x) ( approximately Ks) were calculated by fitting the experimental shelf temperature response to the theoretical value. While the resulting values of K(s) are in general agreement with previously reported values, the values of Ks close to the inlet are significantly higher than those of other locations of the shelf channel. This observation is most likely attributed to the variation of the flow pattern of heat transfer fluid within the channels.

  19. Reflection and refraction of a transient temperature field at a plane interface using Cagniard-de Hoop approach.

    PubMed

    Shendeleva, M L

    2001-09-01

    An instantaneous line heat source located in the medium consisting of two half-spaces with different thermal properties is considered. Green's functions for the temperature field are derived using the Laplace and Fourier transforms in time and space and their inverting by the Cagniard-de Hoop technique known in elastodynamics. The characteristic feature of the proposed approach consists in the application of the Cagniard-de Hoop method to the transient heat conduction problem. The idea is suggested by the fact that the Laplace transform in time reduces the heat conduction equation to a Helmholtz equation, as for the wave propagation. Derived solutions exhibit some wave properties. First, the temperature field is decomposed into the source field and the reflected field in one half-space and the transmitted field in the other. Second, the laws of reflection and refraction can be deduced for the rays of the temperature field. In this connection the ray concept is briefly discussed. It is shown that the rays, introduced in such a way that they are consistent with Snell's law do not represent the directions of heat flux in the medium. Numerical computations of the temperature field as well as diagrams of rays and streamlines of the temperature field are presented.

  20. Computational Fluid Dynamics Simulation of Supersonic Oxygen Jet Behavior at Steelmaking Temperature

    NASA Astrophysics Data System (ADS)

    Alam, Morshed; Naser, Jamal; Brooks, Geoffrey

    2010-06-01

    Supersonic oxygen jets are used in steelmaking and other different metal refining processes, and therefore, the behavior of supersonic jets inside a high temperature field is important for understanding these processes. In this study, a computational fluid dynamics (CFD) model was developed to investigate the effect of a high ambient temperature field on supersonic oxygen jet behavior. The results were compared with available experimental data by Sumi et al. and with a jet model proposed by Ito and Muchi. At high ambient temperatures, the density of the ambient fluid is low. Therefore, the mass addition to the jet from the surrounding medium is low, which reduces the growth rate of the turbulent mixing region. As a result, the velocity decreases more slowly, and the potential core length of the jet increases at high ambient temperatures. But CFD simulation of the supersonic jet using the k-ɛ turbulence model, including compressibility terms, was found to underpredict the potential flow core length at higher ambient temperatures. A modified k-ɛ turbulence model is presented that modifies the turbulent viscosity in order to reduce the growth rate of turbulent mixing at high ambient temperatures. The results obtained by using the modified turbulence model were found to be in good agreement with the experimental data. The CFD simulation showed that the potential flow core length at steelmaking temperatures (1800 K) is 2.5 times as long as that at room temperature. The simulation results then were used to investigate the effect of ambient temperature on the droplet generation rate using a dimensionless blowing number.

  1. Homeostasis and the concept of 'interstitial fluids hierarchy': Relevance of cerebrospinal fluid sodium concentrations and brain temperature control (Review)

    PubMed Central

    Agnati, Luigi F.; Marcoli, Manuela; Leo, Giuseppina; Maura, Guido; Guidolin, Diego

    2017-01-01

    In this review, the aspects and further developments of the concept of homeostasis are discussed also in the perspective of their possible impact in the clinical practice, particularly as far as psychic homeostasis is concerned. A brief historical survey and comments on the concept of homeostasis and allostasis are presented to introduce our proposal that is based on the classical assumption of the interstitial fluid (ISF) as the internal medium for multicellular organisms. However, the new concept of a hierarchic role of ISF of the various organs is introduced. Additionally, it is suggested that particularly for some chemico-physical parameters, oscillatory rhythms within their proper set-ranges should be considered a fundamental component of homeostasis. Against this background, we propose that the brain ISF has the highest hierarchic role in human beings, providing the optimal environment, not simply for brain cell survival, but also for brain complex functions and the oscillatory rhythms of some parameters, such as cerebrospinal fluid sodium and brain ISF pressure waves, which may play a crucial role in brain physio-pathological states. Thus, according to this proposal, the brain ISF represents the real internal medium since the maintenance of its dynamic intra-set-range homeostasis is the main factor for a free and independent life of higher vertebrates. Furthermore, the evolutionary links between brain and kidney and their synergistic role in H2O/Na balance and brain temperature control are discussed. Finally, it is surmised that these two interrelated parameters have deep effects on the Central Nervous System (CNS) higher integrative actions such those linked to psychic homeostasis. PMID:28204813

  2. Temperature gradient-induced fluid pumping inside a single-wall carbon nanotube: A non-equilibrium molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Faraji, Fahim; Rajabpour, Ali

    2016-09-01

    In this paper we investigate the fluid transport inside a single-wall carbon nanotube induced by a temperature gradient along the tube length, focusing on the effect of fluid-wall interaction strength. It is found that the fluid moves from the hot side of the nanotube towards the cold side. By increasing the fluid-wall interaction strength, the fluid volumetric flux assumes a maximum, increases, and then decreases. Fluid transport is pressure-driven in weak interactions; in contrast, in strong interactions, the fluid is broken into two parts in the radial direction. Fluid transport in the central regions of the tube is pressure-driven, while it is surface-driven in the areas close to the wall.

  3. Effects of temperature and pore fluid chemistry on frictional properties of laboratory fault zones

    NASA Astrophysics Data System (ADS)

    Bomberger, C. W.; King, D. S.

    2012-12-01

    The strength and stability of seismogenic faults depends upon the frictional properties of the gouge material. These frictional properties can be further understood through laboratory experiments designed to determine the material response of fault gouge to imposed sliding. We seek to explore the effects of several different brine compositions, concentrations, and temperatures on frictional stability of quartz and gypsum fault gouge. Groundwater is commonly present in areas of active faulting, and it is known from previous studies (Blanpied et al., 1998) that water decrease the frictional strength of fault gouge while the presence of salts can increase frictional strength (Feucht and Logan, 1989). Some of the common ions dissolved in groundwater are Na+, Mg2+, Ca2+, Cl-, and SO42-. These ions may cause varying effects on the frictional stability of faults when present in groundwater depending on the dissolved ionic species, concentration, temperature, and the lithology of the host rock. Rate-step sliding tests and slide-hold-slide tests were preformed on quartz and gypsum powders which simulated fault gouge. Quartz is used as a representation of the bulk continental lithosphere, while gypsum is used for its faster reaction rates in water. Gypsum is also a useful room temperature analog for quartz at elevated temperatures (Muhuri et al. 2003). The double direct shear experiments were preformed submerged in either DI water or a brine solution containing a single salt, over a range of temperatures. Experimental conditions are varied within a single experiment and among sets of experiments. These methods allow us to investigate the effects of strain, fluid temperature, and brine composition on the mechanical properties of fault gouge. Frictional healing for quartz powder does not depend upon brine concentration. For gypsum, healing is greater in a brine solution than in DI water. Differences in healing are also observed depending upon the salt, with Na2SO4 and CaCl2

  4. 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.

  5. 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.

  6. 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.

  7. Dynamic measurement of drilling fluid rheology at elevated temperature and pressure

    SciTech Connect

    Moussa, M.M.; Al-Marhoun, M.A.

    1985-03-01

    Due to instability and degradation of the conventional drilling fluids specially under high shear rate, elevated temperatures and chemically complex environments of deep and geothermal wells, it is essential to modify and develop stable batches of clay suspensions that can perform adequately under these conditions. To obtain batches, a reliable set-up should be designed and constructed to examine and measure all the properties that may possibly change under the prevailing conditions. A scaled dynamic flow loop is designed and built in the Department of Petroleum Engineering at the University of Petroleum and Minerals, Dhahran. This set-up can simulate efficiently the bottomhole condition e.g. high temperature up to 450/sup 0/F, high shear rate up to 50,000 sec/sup -1/. The system pressure is maintained above the saturation pressure of water at the test temperature. Dynamic filteration rate and the corrosion rate is monitored instantaneously at wide range of bottomhole conditions. The flow parameters NandK,/tau/, ..gamma.. etc., are obtained by measuring ..delta..P across the 3-tube viscometer using the DP 15-150 pressure differential transducers. The ambient properties are measured by Baroid multi-speed viscometer and compared with data obtained from the loop. Two batches composed of sepiolite and polymer were tested. Effective viscosity is increased significantly at high temperature for the first and second batches. The consistency and thermal stability of these fluids may be attributed to the transfer of sepiolite to smectite at high temperature and high shear.

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

    SciTech Connect

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

    2010-12-03

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

  9. 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.

  10. Unsteady MHD convective flow of Second grade fluid through a porous medium in a Rotating parallel plate channel with temperature dependent source

    NASA Astrophysics Data System (ADS)

    VeeraKrishna, M.; Subba Reddy, G.

    2016-09-01

    In this paper, we make an initial vale investigation of hydromagnetic convective flow of a viscous electrically conducting second grade fluid through a porous medium in a rotating parallel plate channel in the presence of a temperature dependent heat source. The perturbations in the flow are created by a constant pressure gradient along the plates in addition to non-torsional oscillations of the lower plate. The exact solutions of the velocity and the temperature fields consist of the steady state and the transient components using Laplace transform technique. The time required for the transient effects to decay is discussed in detail and the ultimate steady state consists of boundary layers on the plates and an interior. Attention is focused on the physical nature of the solutions, and the structure of the various kinds of boundary layers formed on the plates. The final steady state velocity and temperature fields are numerically discussed for different values of the governing parameters. The shear stresses and the Nusselt number are tabulated. Particular case when both the plates are at rest has also been computed and analyzed.

  11. 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

  12. Temperature dependence of fluid phase endocytosis coincides with membrane properties of pig platelets.

    PubMed

    Wolkers, Willem F; Looper, Sheri A; Fontanilla, Ray A; Tsvetkova, Nelly M; Tablin, Fern; Crowe, John H

    2003-06-10

    In previous studies we have shown that platelets take up low molecular weight molecules from the medium by fluid phase endocytosis, a phenomenon that we previously have used to load trehalose into human platelets, after which we have successfully freeze-dried them. We now extend those findings to a species to be used in animal trials of freeze-dried platelets:pigs. Further, we report results of studies aimed at elucidating the mechanism of the uptake. Temperature dependence of fluid-phase endocytosis was determined in pig platelets, using lucifer yellow carbohydrazide (LY) as a marker. A biphasic curve of marker uptake versus temperature was obtained. The activation energy was significantly higher above 22 degrees C (18.7+/-1.8 kcal/mol) than below that critical temperature (7.5+/-1.5 kcal/mol). The activation energy of fluid phase endocytosis in human platelets was 24.1+/-1.6 kcal/mol above 15 degrees C. In order to establish a correlation between the effect of temperature on fluid phase endocytosis and the membrane physical state, Fourier transform infrared spectroscopy (FTIR) and fluorescence anisotropy experiments were conducted. FTIR studies showed that pig platelets exhibit a main membrane phase transition at approximately 12 degrees C, and two smaller transitions at 26 and 37 degrees C. Anisotropy experiments performed with 1,6 diphenyl-1,3,5 hexatriene (DPH) complemented FTIR results and showed a major transition at 8 degrees C and smaller transitions at 26 and 35 degrees C. In order to investigate the relative roles of known participants in fluid phase endocytosis, the effects of several chemical inhibitors were investigated. LY uptake was unaffected by colchicine, methylamine, and amiloride. However, disruption of specific microdomains in the membrane (rafts) by methyl-beta-cyclodextrin reduced uptake of LY by 35%. Treatment with cytochalasin B, which inhibits actin polymerization, reduced the uptake by 25%. We conclude that the inflection point in the LY

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Transient Elevation of Cerebrospinal Fluid Protein in a Patient of Mild Encephalitis with Reversible Lesion in the Splenium: A Case Report

    PubMed Central

    SHARMA, Bhawna; HANDA, Rahul; NAGPAL, Kadam; PRAKASH, Swayam; PANAGARIYA, Ashok

    2014-01-01

    Mild encephalitis with reversible lesion in the splenium (MERS) is a clinicoradiological syndrome presenting as a solitary lesion in the central portion of the splenium of the corpus callosum (SCC) with a radiological finding of restricted diffusion and low apparent diffusion coefficient (ADC) values. Complete resolution of the lesion on follow-up imaging and full clinical recovery are the hallmarks of this syndrome, even with only supportive therapy. MERS is usually associated with normal Cerebrospinal fluid (CSF) findings and an excellent prognosis, even without corticosteroid therapy. Magnetic resonance imaging (MRI) is the ideal modality for initial diagnosis and follow-up. Not many cases of this uncommon clinicoradiological syndrome with transient elevation of CSF proteins have been reported. In the subsequent sections, we present a case report of this unusual clinicoradiological entity with raised CSF protein. We also elaborate on possible differential diagnoses and the syndrome’s proposed pathophysiology. PMID:25246843

  19. Study of a Combined Power and Ejector Refrigeration Cycle with Low-temperature Heat Sources by Applying Various Working Fluids

    NASA Astrophysics Data System (ADS)

    Jafarmadar, S.; Habibzadeh, A.

    2017-08-01

    A power and cooling cycle which combines the organic Rankine cycle and the ejector refrigeration cycle supplied by waste heat energy sources is discussed in this paper. Thirteen working fluids including one wet, eight dry and four isentropic fluids are studied in order to find their performances on the combined cycle. First and second law analysis has been performed by using a computer program in order to investigate various operating conditions’ effects on the proposed cycle by fixing power/refrigeration ratio and varying waste heat source and evaporator temperature. According to the results, in general, dry and isentropic ORC fluids have better performance compared with wet fluids. The increase in evaporator temperature leads to the decrease in exergy efficiency. On the other hand, exergy efficiency rises with the turbine inlet temperature decrease and an increase of heat source temperature. Rising expansion ratio and inlet temperature of the turbine causes an increase in the thermal efficiency of the cycle.

  20. Rehydration fluid temperature affects voluntary drinking in horses dehydrated by furosemide administration and endurance exercise.

    PubMed

    Butudom, Prawit; Barnes, Donna J; Davis, Matthew W; Nielsen, Brian D; Eberhart, Susan W; Schott, Harold C

    2004-01-01

    To determine whether temperature of rehydration fluid influences voluntary rehydration by horses, six 2-3-year-old horses were dehydrated (4-5% body weight loss) by a combination of furosemide administration and 30 km of treadmill exercise. For the initial 5 min following exercise, horses were offered a 0.9% NaCl solution at 10, 20, or 30 degrees C. Subsequently, after washing and cooling out, voluntary intake of water at 10, 20, or 30 degrees C from 20 to 60 min after exercise was measured. Fluid intake (FI) during the first 5 min of recovery was 9.8+/-2.5,12.3+/-2.1 and 9.7+/-2.0L (p>0.05) for saline at 10, 20, and 30 degrees C, respectively. Although not a significant finding, horses offered 0.9% NaCl at 20 degrees C tended to take fewer (p=0.07), longer drinks than when saline at either 10 or 30 degrees C was offered. Between 20 and 60 min of recovery, intake of water at 20 degrees C (7.7+/-0.8L) and 30 degrees C (6.6+/-1.2L) was greater (p<0.05) than that at 10 degrees C (4.9+/-0.5L). Thus, total FI was 14.7+/-2.5,19.9+/-2.5, and 16.3+/-2.4L for rehydration fluids at 10, 20, and 30 degrees C, respectively (p<0.05, value for 20 degrees C water greater than that for 10 degrees C water). Although the amount of metabolic heat transferred to the initial saline drink was correlated with the decrease in core temperature during the initial 5 min of recovery, heat transfer to ingested fluid was most likely responsible for the dissipation of, at most, 5% of the heat generated during endurance exercise. In conclusion, following exercise these dehydrated-normothermic horses voluntary drank the greatest amount of fluid at near ambient (20 degrees C) temperature. Although not determined in this study, greater satiation of thirst by oropharyngeal cooling may have contributed to lesser intake of colder (10 degrees C) fluid.

  1. Estimation of internal heat transfer coefficients and detection of rib positions in gas turbine blades from transient surface temperature measurements

    NASA Astrophysics Data System (ADS)

    Heidrich, P.; Wolfersdorf, J. v.; Schmidt, S.; Schnieder, M.

    2008-11-01

    This paper describes a non-invasive, non-destructive, transient inverse measurement technique that allows one to determine internal heat transfer coefficients and rib positions of real gas turbine blades from outer surface temperature measurements after a sudden flow heating. The determination of internal heat transfer coefficients is important during the design process to adjust local heat transfer to spatial thermal load. The detection of rib positions is important during production to fulfill design and quality requirements. For the analysis the one-dimensional transient heat transfer problem inside of the turbine blade's wall was solved. This solution was combined with the Levenberg-Marquardt method to estimate the unknown boundary condition by an inverse technique. The method was tested with artificial data to determine uncertainties with positive results. Then experimental testing with a reference model was carried out. Based on the results, it is concluded that the presented inverse technique could be used to determine internal heat transfer coefficients and to detect rib positions of real turbine blades.

  2. Hamiltonian reduced fluid model for plasmas with temperature and heat flux anisotropies

    NASA Astrophysics Data System (ADS)

    Tassi, E.

    2016-09-01

    For an arbitrary number of species, we derive a Hamiltonian fluid model for strongly magnetized plasmas describing the evolution of the density, velocity, and electromagnetic fluctuations and also of the temperature and heat flux fluctuations associated with motions parallel and perpendicular to the direction of a background magnetic field. We derive the model as a reduction of the infinite hierarchy of equations obtained by taking moments of a Hamiltonian drift-kinetic system with respect to Hermite-Laguerre polynomials in velocity-magnetic-moment coordinates. We show that a closure relation directly coupling the heat flux fluctuations in the directions parallel and perpendicular to the background magnetic field provides a fluid reduction that preserves the Hamiltonian character of the parent drift-kinetic model. We find an alternative set of dynamical variables in terms of which the Poisson bracket of the fluid model takes a structure of a simple direct sum and permits an easy identification of the Casimir invariants. Such invariants in the limit of translational symmetry with respect to the direction of the background magnetic field turn out to be associated with Lagrangian invariants of the fluid model. We show that the coupling between the parallel and perpendicular heat flux evolutions introduced by the closure is necessary for ensuring the existence of a Hamiltonian structure with a Poisson bracket obtained as an extension of a Lie-Poisson bracket.

  3. 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.

  4. 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

  5. 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.

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

    SciTech Connect

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

    1999-09-01

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

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    SciTech Connect

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

    2010-01-01

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

  10. The acute toxicity evaluation of a low-temperature hydraulic fluid.

    PubMed

    Kinkead, E R; Wolfe, R E; Bunger, S K; Leahy, H F

    1992-03-01

    A low-temperature version of MIL-H-83282 (LT 83282) is a candidate hydraulic fluid to be used as a replacement for the current low-temperature fluid used on Strategic Air Command aircraft. A single neat dose of 0.1 mL LT 83282 into New Zealand White (NZW) rabbit eyes resulted in slight conjunctival irritation for up to 24 hr after treatment in two of nine rabbits. Rinsing the eyes after treatment appeared beneficial. A single treatment of 0.5 mL neat LT 83282 to rabbit skin produced no irritation. A total of 40% of the guinea pigs receiving repeated dermal application of the fluid demonstrated a positive sensitization response. A single oral dose of 5 g LT 83282/kg body weight given to five male and five female Fischer 344 (F-344) rats and a single dermal application of 2 g LT 83282/kg body weight applied to five male and five female NZW rabbits resulted in no deaths. Inhalation exposures to aerosol concentrations of LT 83282 resulted in an LC50 of 2.13 and 1.50 mg/L for male and female F-344 rats, respectively. No clinical signs of acute delayed neurotoxicity were observed in hens twice dosed at limit levels (5 g/kg) and observed for 21 days.

  11. Numerical analysis of the transient temperature field of the multilayer insulative systems of Space Shuttle

    NASA Astrophysics Data System (ADS)

    Geng, Weiqun; Yang, Maozhao; Huang, Zhenzhong

    1992-09-01

    The finite difference method and the finite element method have been used to determine the temperature distribution through the multilayer insulative systems of the Space Shuttle. The computed results have been compared with STS-2 flight data and other experimental results; they show good agreement.

  12. Correlating measured transient temperature rises with damage rate processes in cultured cells

    NASA Astrophysics Data System (ADS)

    Denton, Michael L.; Tijerina, Amanda J.; Gonzalez, Cherry C.; Gamboa, B. Giovana; Noojin, Gary D.; Ahmed, Elharith M.; Rickman, John M.; Dyer, Phillip H.; Rockwell, Benjamin A.

    2017-02-01

    Thermal damage rate processes in biological tissues are usually characterized by a kinetics approach. This stems from experimental data that show how the transformation of a specified biological property of cells or biomolecule (plating efficiency for viability, change in birefringence, tensile strength, etc.) is dependent upon both time and temperature. Here, two disparate approaches were used to study thermal damage rate processes in cultured retinal pigment epithelial cells. Laser exposure (photothermal) parameters included 2-μm laser exposure of non-pigmented cells and 532-nm exposures of cells possessing a variety of melanosome particle densities. Photothermal experiments used a mid-IR camera to record temperature histories with spatial resolution of about 8 μm, while fluorescence microscopy of the cell monolayers identified threshold damage at the boundary between live and dead cells. Photothermal exposure durations ranged from 0.05-20 s, and the effects of varying ambient temperature were investigated. Temperature during heat transfer using a water-jacketed cuvette was recorded with a fast microthermister, while damage and viability of the suspended cells were determined as percentages. Exposure durations for the heat transfer experiments ranged from 50- 60 s. Empirically-determined kinetic parameters for the two heating methods were compared with each other, and with values found in the literature.

  13. Electron temperature response to ECRH on FTU tokamak in transient conditions.

    NASA Astrophysics Data System (ADS)

    Jacchia, A.; Bruschi, A.; Cirant, S.; Granucci, G.; Sozzi, C.; de Luca, F.; Amadeo, P.; Bracco, G.; Tudisco, O.

    2001-10-01

    Steady-state electron heat transport analysis of FTU high density plasmas under Electron Cyclotron Heating (ECRH) shows "stiff" electron temperature profiles [1,2,3]. Plasma response to off-axis EC heating, in fact, exibits a lower limit to electron temperature gradient length, Lc , below which electron thermal conductivity switches to higher values. Stiffness, however, is attenuated in the plasma core of saw-tooth free discharges with flat-hollow temperature profile and during current ramp-up [3,4,5], in which cases the temperature gradient length can be brought to very low values by means of on-axis ECH. Steady and current ramp-up discharges probed by steady and modulated ECH are analyzed in terms of stiffnes. Critical gradient length dependence on local features of computed current density profile is discussed. [1] Sozzi, C. et al., Paper EXP5/13, Plasma Phys. Contr. Fus. Res., Proc.18th IAEA Conf., Sorrento, 2000. [2] Jacchia, A. et al. Topical Conference on Radio Frequency Power in Plasmas, Oxnard, USA, (2001). [3] Cirant, S. et al. Topical Conference on Radio Frequency Power in Plasmas, Oxnard, USA, (2001). [4] Sozzi, C. et al., EPS, Madeira 2001. [5] Bracco, G. et al.,Plasma Phys. Contr. Fus. Res., Proc.18th IAEA Conf., Sorrento, 2000.

  14. A transient hot-wire instrument for thermal conductivity measurements in electrically conducting liquids at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Alloush, A.; Gosney, W. B.; Wakeham, W. A.

    1982-09-01

    This paper describes a novel type of transient hot-wire cell for thermal conductivity measurements on electrically conducting liquids. A tantalum wire of 25 μm. diameter is used as the sensing element in the cell, and it is insulated from the conducting liquids by an anodic film of tantalum pentoxide, 70 nm thick. The cell is suitable for measurements on conducting liquids at elevated temperatures. The results of test measurements on liquid water at its saturation vapor pressure are reported in order to confirm the correct operation of the thermal conductivity cell. The data, which have an estimated accuracy of ±3%, depart by less than ±1.8% from the correlation proposed by the International Association for the Properties of Steam. Results are also presented for concentrated aqueous solutions of lithium bromide, which are frequently used in absorption refrigerator cycles.

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

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Reddy, Ramana G.

    2017-03-01

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

  16. Tissue temperature transients in resting contra-lateral leg muscle tissue during isolated knee extension.

    PubMed

    Kenny, Glen P; Reardon, Frank D; Ducharme, Michel B; Reardon, Mark L; Zaleski, Wytek

    2002-12-01

    This study was designed to evaluate the role of non-active tissue in the retention and dissipation of heat during and following intense isolated muscle activity. Six subjects performed an incremental isotonic test (constant angular velocity, increases in force output) on a KIN-COM isokinetic apparatus to determine their maximal oxygen consumption during single knee extensions (VO2sp). In a subsequent session, a thin wire multi-sensor temperature probe was inserted into the left vastus medialis under ultrasound guidance at a specific internal marker. The deepest temperature sensor (tip, Tmu10) was located approximately 10 mm from the femur and deep femoral artery with 2 additional sensors located at 15 (Tmu25) and 30 (Tmu40) mm from the tip. Implant site was midway between and medial to a line joining the anterior superior iliac spine and base of patella. Esophageal temperature (Tes) temperature was measured as an index of core temperature. Subjects rested in a supine position for 60 min followed by 30 min of seated rest in an ambient condition of 22 degree C. Subjects then performed 15 min of isolated single right knee extensions against a dynamic resistance on a KIN COM corresponding to 60% of VO2sp at 60 degree x sec(-1). Exercise was followed by 60 min of seated rest. Resting Tes was 37 degree C while Tmu10, Tmu25, and Tmu40 were 36.58, 36.55 and 36.45 degree C, respectively. Exercise resulted in a Tes increase of 0.31 C above pre-exercise resting. Tmu of the non-exercising leg increased 0.23, 0.19 and 0.09 degree C for Tmu10, Tmu25, and Tmu40, respectively. While Tes decreased to baseline values within approximately 15 min of end-exercise, Tmu10 reached resting values following approximately 40 min of recovery. These results suggest that during isolated muscle activity, convective heat transfer by the blood to non-active muscle tissue may have a significant role in maintaining resting core temperature.

  17. Fractional-calculus model for temperature and pressure waves in fluid-saturated porous rocks.

    PubMed

    Garra, Roberto

    2011-09-01

    We study a fractional time derivative generalization of a previous Natale-Salusti model about nonlinear temperature and pressure waves, propagating in fluid-saturated porous rocks. Their analytic solutions, i.e., solitary shock waves characterized by a sharp front, are here generalized, introducing a formalism that allows memory mechanisms. In realistic wave propagation in porous media we must take into account spatial or temporal variability of permeability, diffusivity, and other coefficients due to the system "history." Such a rock fracturing or fine particulate migration could affect the rock and its pores. We therefore take into account these phenomena by introducing a fractional time derivative to simulate a memory-conserving formalism. We also discuss this generalized model in relation to the theory of dynamic permeability and tortuosity in fluid-saturated porous media. In such a realistic model we obtain exact solutions of Burgers' equation with time fractional derivatives in the inviscid case.

  18. 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.

  19. A two-fluid-model analysis on transient, internal-convection heat transfer of He II in a vertical Gorter-Mellink duct heated at the bottom surface

    NASA Astrophysics Data System (ADS)

    Rao, Van F.; Fukuda, Kenji; Horie, Hideki

    This paper deals with the flow and heat transfer of superfluid helium in a vertical Gorter-Mellink duct. Numerical simulation is performed using basic equations of the two-fluid model, with the dissipation due to the Gorter-Mellink two-fluid mutual friction added to the transport equation of entropy. The results indicate different patterns of thermal wave propagation induced by a stepwise heating. For a very low heat flux, the thermal energy will be transported mainly by the unique second-sound wave in He II, while for a higher heat flux it will be transported mainly by thermal diffusion. If the heat flux is higher than a limiting value, the temperature at the heated surface will increase sharply to reach the critical value for phase transition or boiling initiation. While when the heat flux is lower than the limiting value, the temperature distribution in the duct will reach an equilibrium showing either a high or a low thermal conductivity. The level of the thermal conductivity is found to be related to the level of the dissipation due to the two-fluid mutual friction, which is determined by the local temperature and heat flux. The numerically predicted limiting heat flux is also compared with the experimental data by Van Sciver, and the agreement is satisfactory.

  20. 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. © FASEB.

  1. Determination of transient radial-azimuthal temperature distributions in fuel bundles under loss-of-coolant-accident conditions

    SciTech Connect

    Saltos, N.T.; Christensen, R.N.; Aldemir, T.

    1988-10-01

    A methodology is presented to determine the transient temperature distributions in fuel bundles under loss-of-coolant accident (LOCA) conditions using a recently developed variational technique for the solution of radial-azimuthal heat conduction in the fuel rods and the modified view factor concept proposed by Uchida and Nakamure to model the radiative heat transfer between the rods. The variational technique is based on the Lebron-Labermont restricted variational principle and represents the temperature distribution in the rods at a given time during the LOCA via parabolic and circular trial functions in the radial and azimuthal directions, respectively. The methodology is implemented to a 4 x 4 boiling water reactor fuel bundle under typical LOCA conditions to investigate the effects of changes in rod heat transfer characteristics and simplifying modeling assumptions on predicted rod temperature distributions. The results show that these effects depend on the rod location in the assembly and LOCA phase under consideration and indicate that same degree of modelling detail may not be necessary for all the rods in the bundle at all times during the LOCA.

  2. Direct observation of ground-state lactam–lactim tautomerization using temperature-jump transient 2D IR spectroscopy

    PubMed Central

    Peng, Chunte Sam; Baiz, Carlos R.; Tokmakoff, Andrei

    2013-01-01

    We provide a systematic characterization of the nanosecond ground-state lactam–lactim tautomerization of pyridone derivatives in aqueous solution under ambient conditions using temperature-jump transient 2D IR spectroscopy. Although electronic excited-state tautomerization has been widely studied, experimental work on the ground electronic state, most relevant to chemistry and biology, is lacking. Using 2D IR spectroscopy, lactam and lactim tautomers of 6-chloro-2-pyridone and 2-chloro-4-pyridone are unambiguously identified by their unique cross-peak patterns. Monitoring the correlated exponential relaxation of these signals in response to a laser temperature jump provides a direct measurement of the nanosecond tautomerization kinetics. By studying the temperature, concentration, solvent, and pH dependence, we extract a thermodynamic and kinetic characterization and conclude that the tautomerization proceeds through a two-state concerted mechanism. We find that the intramolecular proton transfer is mediated by bridging water molecules and the reaction barrier is dictated by the release of a proton from pyridone, as would be expected for an efficient Grothuss-type proton transfer mechanism. PMID:23690588

  3. Numerical Simulation of Transient Development of Flame, Temperature and Velocity under Reduced Gravity in a Methane Air Diffusion Flame

    NASA Astrophysics Data System (ADS)

    Bhowal, Arup Jyoti; Mandal, Bijan Kumar

    2017-02-01

    A methane air co flow diffusion flame has been numerically simulated with the help of an in-house developed code at normal gravity, 0.5 G, and 0.0001 G (microgravity) for the study of transient behavior of the flame in terms of flame shape, temperature profile and velocity (streamlines). The study indicates that lower is the gravity level, the higher is the time of early transience. The flame developments during transience are marked by the formation of a secondary flamelet at different heights above the primary flame at all gravity levels. The development of temperature profile at microgravity takes a much longer time to stabilize than the flame development. At normal gravity and 0.5 G gravity level, streamlines, during transience, show intermediate vortices which are finally replaced by recirculation of ambient air from the exit plane. At microgravity, neither any vortex nor any recirculation at any stage is observed. Centerline temperature plots, at all gravity levels during transience, demonstrate a secondary peak at some instants as a consequence of the secondary flamelet formation. The centerline velocity at microgravity decreases gradually during transience, unlike at other two gravity levels where the fall is very sharp and is indicative of negligible buoyancy at microgravity.

  4. 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.

  5. Ion Temperatures in Earth's Inner Magnetosphere: Ring Current Dynamics, Transient Effects, and Data-Model Comparisons

    NASA Astrophysics Data System (ADS)

    Elfritz, Justin G.

    Earth's magnetosphere is an inherently complex, strongly nonlinear system with intrinsic coupling between internal and external drivers. In general, magnetospheric systems can be understood as a balance between multiple regions which all exhibit unique plasma properties. The feedback processes between each region depend on geomagnetic activity levels and the preceding states of the solar wind and the respective magnetospheric regions. Of particular interest is understanding how ion temperatures evolve during geomagnetically active periods, and also understanding the space weather impacts of hot ion populations injected during such periods. Dynamic, spatiotemporally resolved ion temperature boundary conditions have been implemented into the Comprehensive Ring Current Model (CRCM); the temperatures are based on 2-D equatorial maps derived from remotely imaged energetic neutral atom (ENA) measurements. The high-speed-stream-driven event on 22 July 2009 and the coronal mass ejection-driven event on 30-31 October 2013 are simulated and compared against identical simulations using a statistically derived boundary condition model. This new method for establishing boundary conditions allows users to include event-specific observations associated with a dynamic plasma sheet. It is found that spatial and energy distributions in the storm-time ring current exhibit sensitive dependence on boundary conditions during these events. The coupling of boundary conditions to the time history of the convection electric field strength is found to play an important role in throttling the influence of the boundary plasma on the inner magnetosphere. Storm-time dusk-dawn asymmetries consistent with observational data are reproduced well when CRCM is provided with the event-specific boundary condition model. The dependence of average, global magnetospheric ion temperatures derived from ENA maps is also investigated as a function of various combinations of solar wind parameters, IMF

  6. Influence of hydrological, biogeochemical and temperature transients on subsurface carbon fluxes in a flood plain environment

    SciTech Connect

    Arora, Bhavna; Spycher, Nicolas F.; Steefel, Carl I.; Molins, Sergi; Bill, Markus; Conrad, Mark E.; Dong, Wenming; Faybishenko, Boris; Tokunaga, Tetsu K.; Wan, Jiamin; Williams, Kenneth H.; Yabusaki, Steven B.

    2016-02-01

    Flood plains play a potentially important role in the global carbon cycle. The accumulation of organic matter in flood plains often induces the formation of chemically reduced groundwater and sediments along riverbanks. In this study, our objective is to evaluate the cumulative impact of such reduced zones, water table fluctuations, and temperature gradients on subsurface carbon fluxes in a flood plain at Rifle, Colorado located along the Colorado River. 2-D coupled variably-saturated, non-isothermal flow and biogeochemical reactive transport modeling was applied to improve our understanding of the abiotic and microbially mediated reactions controlling carbon dynamics at the Rifle site. Model simulations considering only abiotic reactions (thus ignoring microbial reactions) underestimated CO2 partial pressures observed in the unsaturated zone and severely underestimated inorganic (and overestimated organic) carbon fluxes to the river compared to simulations with biotic pathways. Both model simulations and field observations highlighted the need to include microbial contributions from chemolithoautotrophic processes (e.g., Fe?2 and S-2 oxidation) to match locally-observed high CO2 concentrations above reduced zones. Observed seasonal variations in CO2 concentrations in the unsaturated zone could not be reproduced without incorporating temperature gradients in the simulations. Incorporating temperature fluctuations resulted in an increase in the annual groundwater carbon fluxes to the river by 170 % to 3.3 g m-2 d-1, while including water table variations resulted in an overall decrease in the simulated fluxes. We conclude that spatial microbial and redox zonation as well as temporal fluctuations of temperature and water table depth contribute significantly to subsurface carbon fluxes in flood plains and need to be represented appropriately in model simulations.

  7. Choice of optimal working fluid for binary power plants at extremely low temperature brine

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Shipkov, A. A.; Sorokina, E. V.

    2016-12-01

    The geothermal energy development problems based on using binary power plants utilizing lowpotential geothermal resources are considered. It is shown that one of the possible ways of increasing the efficiency of heat utilization of geothermal brine in a wide temperature range is the use of multistage power systems with series-connected binary power plants based on incremental primary energy conversion. Some practically significant results of design-analytical investigations of physicochemical properties of various organic substances and their influence on the main parameters of the flowsheet and the technical and operational characteristics of heat-mechanical and heat-exchange equipment for binary power plant operating on extremely-low temperature geothermal brine (70°C) are presented. The calculation results of geothermal brine specific flow rate, capacity (net), and other operation characteristics of binary power plants with the capacity of 2.5 MW at using various organic substances are a practical interest. It is shown that the working fluid selection significantly influences on the parameters of the flowsheet and the operational characteristics of the binary power plant, and the problem of selection of working fluid is in the search for compromise based on the priorities in the field of efficiency, safety, and ecology criteria of a binary power plant. It is proposed in the investigations on the working fluid selection of the binary plant to use the plotting method of multiaxis complex diagrams of relative parameters and characteristic of binary power plants. Some examples of plotting and analyzing these diagrams intended to choose the working fluid provided that the efficiency of geothermal brine is taken as main priority.

  8. Fast transient infrared studies in material science: development of a novel low dead-volume, high temperature DRIFTS cell.

    PubMed

    Dal Santo, V; Dossi, C; Fusi, A; Psaro, R; Mondelli, C; Recchia, S

    2005-04-30

    A prototype DRIFTS flow reaction chamber was designed and developed in order to find analytical application in the study of heterogeneous catalysts operating at high temperatures under fast transient gas feed conditions. Minimisation of dead-volumes allows gas replacement in 8-10s at 10mLmin(-1) total flow. To overcome problems related to the reactivity of the cell walls under alternating oxidizing/reducing gases, the cell was built with Inconel 600trade mark, which was tested to be very inert even at high temperatures. The sample holder, which was developed to closely resemble a micro plug-flow reactor, poses some problems in terms of heat transfer to the outer body of the cell (limiting then the maximum reachable temperature) and of the correct measurement of the actual sample temperature. These problems were solved with a careful re-design of the upper part of the cell. The second prototype thus derived is able to reach temperatures up to 803K and allows gas replacement in less than 4s at 10mLmin(-1). The cell is inserted in a MCT-FT-IR, which allows to collect high quality spectra with a 1s time-resolution. The downstream flow can be analysed by a quadrupole mass spectrometer equipped with an enclosed source and by a commercial GC. The performances of this prototype cell are presented showing some tests carried out with ceria-zirconia (Ce(x)Zr(1-x)O(2)) catalysts for CO abatement under real operando conditions.

  9. Temperature and amplitude dependence of tension transients in glycerinated skeletal and insect fibrillar muscle.

    PubMed Central

    Abbott, R H; Steiger, G J

    1977-01-01

    1. Quick stretches and releases were applied to small bundles of glycerinated fibres of rabbit psoas and insect fibrillar flight muscle. The resulting tension changes were recorded at various temperatures and amplitudes of length change. The results from the two preparations had many features in common. At temperatures near 0 degrees C the asymmetry of the initial tension recovery after stretch and release originally reported in living frog fibres by Huxley & Simmons (1971 alpha) was very obvious. 2. The complete tension course could be described as an elastic change occurring simultaneously with the length change followed by recovery consisting of the sum of a number of exponential terms. These terms usually corresponded to the phases discernible without curve fitting, but in some cases a monotonic rise or fall of tension was seen to consist of two components only after curve fitting. 3. After either stretch or release there was a phase of rapid tension recovery towards the value before the length change. The rate constant of this phase increased as the amplitude of stretch or release was increased to about 2 nm/half sarcomere. At higher amplitudes it remained nearly constant 4. At temperatures near 0 degrees C there was a second and much slower continuation of the recovery after stretch. The rate constant of this second phase was much more sensitive to temperature than that of the first phase and it became slower with increasing amplitude of stretch. As the temperature was raised the speed of the second phase approached the speed of the first phase so that at room temperatures the initial tension recovery after stretch and release was nearly symmetrical. 5. Under many conditions these processes were followed by a change in the opposite direction, the 'delayed tension' described by earlier workers. This third phase of tension change had about the same temperature sensitivity as the second phase of the recovery seen after stretch. The tension due to stretch

  10. 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

  11. Computational Fluid Dynamics Analysis on Radiation Error of Surface Air Temperature Measurement

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Liu, Qing-Quan; Ding, Ren-Hui

    2017-01-01

    Due to solar radiation effect, current air temperature sensors inside a naturally ventilated radiation shield may produce a measurement error that is 0.8 K or higher. To improve air temperature observation accuracy and correct historical temperature of weather stations, a radiation error correction method is proposed. The correction method is based on a computational fluid dynamics (CFD) method and a genetic algorithm (GA) method. The CFD method is implemented to obtain the radiation error of the naturally ventilated radiation shield under various environmental conditions. Then, a radiation error correction equation is obtained by fitting the CFD results using the GA method. To verify the performance of the correction equation, the naturally ventilated radiation shield and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated temperature measurement platform serves as an air temperature reference. The mean radiation error given by the intercomparison experiments is 0.23 K, and the mean radiation error given by the correction equation is 0.2 K. This radiation error correction method allows the radiation error to be reduced by approximately 87 %. The mean absolute error and the root mean square error between the radiation errors given by the correction equation and the radiation errors given by the experiments are 0.036 K and 0.045 K, respectively.

  12. 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.

  13. 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.

  14. Effects of transient and persistent cerebrospinal fluid drainage on sleep disordered breathing in patients with idiopathic adult hydrocephalus syndrome

    PubMed Central

    Kristensen, B.; Malm, J.; Rabben, T.

    1998-01-01

    OBJECTIVES—To examine sleep disordered breathing including obstructive sleep apnoea in patients with idiopathic adult hydrocephalus syndrome (IAHS) and to study the effects of CSF drainage and shunting procedure on sleep disordered breathing.
METHODS—In 17 patients with IAHS polysomnographic investigations were performed before and after lumbar CSF drainage and after shunt operation.
RESULTS—Baseline investigations documented a high prevalence of sleep related obstructive respiratory events (respiratory disturbance index >10 in 65% of the patients) and impaired sleep structure. There was no correlation between respiratory disturbance index and CSF pressure. Minimum oxygen saturation was highly correlated with cognitive function. Neither lumbar CSF drainage nor shunting alleviated the respiratory disturbance index. REM and delta sleep increased initially after shunting but there was no sustained effect on sleep quality.
CONCLUSIONS—Sleep disordered breathing is a prevalent finding in patients with IAHS. The shortcoming of CSF drainage to improve sleep disordered breathing either transiently or permanently implies that sleep disordered breathing is a coexistent condition, or an irreversible consequence of the hydrocephalus, with a potential of causing additional dysfunction in IAHS.

 PMID:9771772

  15. Heteromeric heat-sensitive transient receptor potential channels exhibit distinct temperature and chemical response.

    PubMed

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

    2012-03-02

    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.

  16. 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

  17. 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.

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

    SciTech Connect

    Yamagishi, Osamu Sugama, Hideo

    2016-03-15

    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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Bounded anisotropy fluid model for ion temperature evolution applied to AMPTE/IRM magnetosheath data

    NASA Astrophysics Data System (ADS)

    Denton, Richard E.; Li, Xinlin; Phan, Tai-Duc

    1995-08-01

    The proton temperature ratio T⊥/T ∥ measured by the AMPTE/CCE spacecraft under conditions of high solar wind dynamic pressure follows closely the relation T⊥/T∥ =(T⊥/T∥)β≡1+0.85β-0.48∥. On the basis of this relation, a bounded anisotropy fluid model was developed which describes the temperature evolution of a collisionless anisotropic (T⊥≠T∥) plasma including the effect of energy exchange due to pitch angel scattering by cyclotron waves. This model has been shown to well predict the ion temperature evolution within the magnetosheath close to the magnetopause as observed by CCE. The model was also successful in explaining the temperature evolution of data from the AMPTE/IRM spacecraft averaged over more general solar wind conditions, despite the fact that much of the IRM data lay well below the CCE relation. Here, we make a more thorough comparison of the bounded anisotropy model with the IRM data. Three example IRM crossings are shown: (1) a case with the temperature ratio T⊥/T∥ closely following the CCE relation, (2) a case with T⊥/T∥ closely following the functional form of the CCE relation, but at a lower value, and (3) a case where T⊥/T∥ often falls well below and evolves in a manner unrelated to the CCE relation. These three cases roughly exhibit the range of typical behavior in the entire IRM data set. In all three cases, it is clear that the CCE relation represents an approximate upper bound on the anisotropy and that the ion cyclotron waves control the temperature evolution when the anisotropy is driven up to this bound. The bounded anisotropy model is successful in explaining the temperature evolution in the first two cases and the gross features of the third. In the third case, large fluctuations in temperature were probably due to temporal changes in magnetosheath conditions.

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

    SciTech Connect

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

    2016-08-15

    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.

  7. Pore fluid constraints on the temperature and oxygen isotopic composition of the glacial ocean

    SciTech Connect

    Schrag, D.P.; Hampt, G.; Murray, D.W.

    1996-06-28

    Pore fluids from the upper 60 meters of sediment 3000 meters below the surface of the tropical Atlantic indicate that the oxygen isotopic composition ({delta}{sup 18}O) of seawater at this site during the last glacial maximum was 0.8 {plus_minus} 0.1 per mil higher than it is today. Combined with the {delta}{sup 18}O change in benthic foraminifera from this region, the elevated ratio indicates that the temperature of deep water in the tropical Atlantic Ocean was 4{degree}C colder during the last glacial maximum. Extrapolation from this site to a global average suggests that the ice volume contribution to the change in {delta}{sup 18}O of foraminifera is 1.0 per mil, which partially reconciles the foraminiferal oxygen isotope record of tropical sea surface temperatures with estimates from Barbados corals and terrestrial climate proxies. 25 refs., 3 figs.

  8. Guggenheim's rule and the enthalpy of vaporization of simple and polar fluids, molten salts, and room temperature ionic liquids.

    PubMed

    Weiss, Volker C

    2010-07-22

    One of Guggenheim's many corresponding-states rules for simple fluids implies that the molar enthalpy of vaporization (determined at the temperature at which the pressure reaches 1/50th of its critical value, which approximately coincides with the normal boiling point) divided by the critical temperature has a value of roughly 5.2R, where R is the universal gas constant. For more complex fluids, such as strongly polar and ionic fluids, one must expect deviations from Guggenheim's rule. Such a deviation has far-reaching consequences for other empirical rules related to the vaporization of fluids, namely Guldberg's rule and Trouton's rule. We evaluate these characteristic quantities for simple fluids, polar fluids, hydrogen-bonding fluids, simple inorganic molten salts, and room temperature ionic liquids (RTILs). For the ionic fluids, the critical parameters are not accessible to direct experimental observation; therefore, suitable extrapolation schemes have to be applied. For the RTILs [1-n-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides, where the alkyl chain is ethyl, butyl, hexyl, or octyl], the critical temperature is estimated by extrapolating the surface tension to zero using Guggenheim's and Eotvos' rules; the critical density is obtained using the linear-diameter rule. It is shown that the RTILs adhere to Guggenheim's master curve for the reduced surface tension of simple and moderately polar fluids, but that they deviate significantly from his rule for the reduced enthalpy of vaporization of simple fluids. Consequences for evaluating the Trouton constant of RTILs, the value of which has been discussed controversially in the literature, are indicated.

  9. From single-particle to collective effective temperatures in an active fluid of self-propelled particles

    NASA Astrophysics Data System (ADS)

    Levis, Demian; Berthier, Ludovic

    2015-09-01

    We present a comprehensive analysis of effective temperatures based on fluctuation-dissipation relations in a model of an active fluid composed of self-propelled hard disks. We first investigate the relevance of effective temperatures in the dilute and moderately dense fluids. We find that a unique effective temperature does not in general characterize the non-equilibrium dynamics of the active fluid over this broad range of densities, because fluctuation-dissipation relations yield a lengthscale-dependent effective temperature. By contrast, we find that the approach to a non-equilibrium glass transition at very large densities is accompanied by the emergence of a unique effective temperature shared by fluctuations at all lengthscales. This suggests that an effective thermal dynamics generically emerges at long times in very dense suspensions of active particles due to the collective freezing occurring at non-equilibrium glass transitions.

  10. Response of an old-growth tropical rainforest to transient high temperature and drought.

    PubMed

    Silva, Carlos E; Kellner, James R; Clark, David B; Clark, Deborah A

    2013-11-01

    Tropical rainforests have experienced episodes of severe heat and drought in recent decades, and climate models project a warmer and potentially drier tropical climate over this century. However, likely responses of tropical rainforests are poorly understood due to a lack of frequent long-term measurements of forest structure and dynamics. We analyzed a 12-year record (1999-2010) of 47 817 annual measurements of canopy height to characterize the response of an old-growth Neotropical rainforest to the severe heat and drought associated with the 1997-1998 El Niño. Well-drained soils on slopes and plateaus experienced a threefold increase in the fraction of the landscape in gaps (≤2 m) and a reduction in the fraction in high canopy (>15 m) causing distributions of canopy height to depart from equilibrium for a period of 2-3 years. In contrast, forests on low-lying alluvial terraces remained in equilibrium and were nearly half as likely to experience upper canopy (>15 m) disturbance over the 12 years of observation. Variation in forest response across topographic positions suggests that tropical rainforests are more sensitive to moisture deficits than high temperature and that topography likely structures landscape-level variation in the severity of drought impacts. © 2013 John Wiley & Sons Ltd.

  11. Evaluation of micro tip pressure transducers for the measurement of intracerebral pressure transients induced by fluid percussion.

    PubMed

    Walter, B; Bauer, R; Fritz, H; Jochum, T; Wunder, L; Zwiener, U

    1999-02-01

    We describe the application of MIKRO TIP miniature pressure transducers (MPT) for the in vivo measurement of intracerebral stresses induced by traumatic brain injury (TBI). In order to test the linearity of these transducers pressure pulses of different amplitudes (duration approximately 10ms) were generated in a closed calibration chamber. A piezoelectric pressure transducer (PPT) served as the reference measure. A linear correlation was found within the pressure range between 0.57 and 5.09 bar (R2 = 0.998). The frequency transmission characteristics of the MPTs are comparable to the PPT. In three juvenile swines (6 weeks of age) pressures within the brain tissue were induced by fluid percussion (FP) and were measured in the anterior, middle, and posterior cranial cavity as well as in the extracranial part of the medulla oblongata. The data obtained in our experiments agree with the basic biomechanics of FP known from studies in cats and rabbits. Due to their small size, MPTs can be applied in living animals. Stereotaxic positioning of these catheters at any site of the brain and spinal cord requires only minimal surgery. Therefore, MPTs are useful in evaluating animal models of brain injury and in generating input data for computational models of head injury as well as to validate the mathematical results of such models with experimental data.

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

    PubMed Central

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

    2000-01-01

    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

  14. Aluminum speciation in aqueous fluids at deep crustal pressure and temperature

    NASA Astrophysics Data System (ADS)

    Mookherjee, Mainak; Keppler, Hans; Manning, Craig E.

    2014-05-01

    We investigated aluminum speciation in aqueous fluids in equilibrium with corundum using in situ Raman spectroscopy in hydrothermal diamond anvil cells to 20 kbar and 1000 °C. We have studied aluminum species in (a) pure H2O, (b) 5.3 m KOH solution, and (c) 1 m KOH solution. In order to better understand the spectral features of the aqueous fluids, we used ab initio simulations based on density functional theory to calculate and predict the energetics and vibrational spectra for various aluminum species that are likely to be present in aqueous solutions. The Raman spectra of pure water in equilibrium with Al2O3 are devoid of any characteristic spectral features. In contrast, aqueous fluids with 5.3 m and 1 m KOH solution in equilibrium with Al2O3 show a sharp band at ˜620 cm-1 which could be attributed to the [ species. The band grows in intensity with temperature along an isochore. A shoulder on the high-frequency side of this band may be due to a hydrated, charge neutral Al(OH)3·H2O species. In the limited pressure, temperature and density explored in the present study, we do not find any evidence for the polymerization of the [ species to dimers [(OH)2-Al-(OH)2-Al(OH)2] or [(OH)3-Al-O-Al(OH)3]2-. This is likely due to the relatively low concentration of Al in the solutions and does not rule out significant polymerization at higher pressures and temperatures. Upon cooling of Al-bearing solutions to room temperatures, Raman bands indicating the precipitation of diaspore (AlOOH) were observed in some experiments. The Raman spectra of the KOH solutions (with or without dissolved alumina) showed a sharp OH stretching band at ˜3614 cm-1 and an in-plane OH bending vibration at ˜1068 cm-1, likely related to an OH- ion with the oxygen atom attached to a water molecule by hydrogen bonding. A weak feature at ˜935 cm-1 may be related to the out-of-plane bending vibration of the same species or to an OH species with a different environment.

  15. Superfluid to Normal Fluid Phase Transition in the Bose Gas Trapped in Two-Dimensional Optical Lattices at Finite Temperature

    NASA Astrophysics Data System (ADS)

    Pires, M. O. C.; de Passos, E. J. V.

    2017-02-01

    We develop the Hartree-Fock-Bogoliubov theory at finite temperature for Bose gas trapped in the two-dimensional optical lattice with the on-site energy low enough that the gas presents superfluid properties. We obtain the condensate density as function of the temperature neglecting the anomalous density in the thermodynamics equation. The condensate fraction provides two critical temperature. Below the temperature T_{C1}, there is one condensate fraction. Above two condensate fractions merger up to the critical temperature T_{C2}. At temperatures larger than T_{C2}, the condensate fraction is null and, therefore, the gas is normal fluid. We resume by a finite-temperature phase diagram where three domains can be identified: the normal fluid, the superfluid with one stable condensate fraction and the superfluid with two condensate fractions being unstable one of them.

  16. Natural convection in Bingham plastic fluids from an isothermal spheroid: Effects of fluid yield stress, viscous dissipation and temperature-dependent viscosity

    NASA Astrophysics Data System (ADS)

    Gupta, Anoop Kumar; Gupta, Sanjay; Chhabra, Rajendra Prasad

    2017-08-01

    In this work, the buoyancy-induced convection from an isothermal spheroid is studied in a Bingham plastic fluid. Extensive results on the morphology of approximate yield surfaces, temperature profiles, and the local and average Nusselt numbers are reported to elucidate the effects of the pertinent dimensionless parameters: Rayleigh number, 102 ≤ Ra ≤ 106; Prandtl number, 20 ≤ Pr ≤ 100; Bingham number, 0 ≤ Bn ≤ 103, and aspect ratio, 0.2 ≤ e ≤ 5. Due to the fluid yield stress, fluid-like (yielded) and solid-like (unyielded) regions coexist in the flow domain depending upon the prevailing stress levels vis-a-vis the value of the fluid yield stress. The yielded parts progressively grow in size with the rising Rayleigh number while this tendency is countered by the increasing Bingham and Prandtl numbers. Due to these two competing effects, a limiting value of the Bingham number ( Bn max) is observed beyond which heat transfer occurs solely by conduction due to the solid-like behaviour of the fluid everywhere in the domain. Such limiting values bear a positive dependence on the Rayleigh number ( Ra) and aspect ratio ( e). In addition to this, oblate shapes ( e < 1) foster heat transfer with respect to spheres ( e = 1) while prolate shapes ( e > 1) impede it. Finally, simple predictive expressions for the maximum Bingham number and the average Nusselt number are developed which can be used to predict a priori the overall heat transfer coefficient in a new application. Also, a criterion is developed in terms of the composite parameter Bn• Gr-1/2 which predicts the onset of convection in such fluids. Similarly, another criterion is developed which delineates the conditions for the onset of settling due to buoyancy effects. The paper is concluded by presenting limited results to delineate the effects of viscous dissipation and the temperature-dependent viscosity on the Nusselt number. Both these effects are seen to be rather small in Bingham plastic fluids.

  17. Temperature-dependent Physical Properties of a HIFU Blood Mimicking Fluid

    NASA Astrophysics Data System (ADS)

    Liu, Yunbo; Maruvada, Subha; King, Randy L.; Herman, Bruce A.; Wear, Keith A.

    2009-04-01

    A blood mimicking fluid (BMF) has been developed and characterized in a temperature dependent manner for high intensity focused ultrasound (HIFU) ablation devices. The BMF is based on a degassed and de-ionized water solution dispersed with low density polyethylene micro-spheres, nylon particles, gellan gum and glycerol. A broad range of physical parameters, including frequency dependent ultrasound attenuation, speed of sound, viscosity, thermal conductivity and diffusivity were characterized as a function of temperature (20° C to 70° C). The nonlinear parameter B/A and backscatter coefficient were also measured at room temperature. The attenuation coefficient is linearly proportional to the frequency (2 MHz-8 MHz) with a slope of about 0.2 dB cm-1 MHz-1 in the 20° C to 70° C range as has been reported for human blood. All the other temperature dependent physical parameters are also close to the reported values in human blood. These properties make the BMF a useful HIFU research tool for developing standardized exposimetry techniques, validating numerical models, and determining the safety and efficacy of HIFU ablation devices.

  18. Cytological analysis of equine bronchoalveolar lavage fluid. Part 3: The effect of time, temperature and fixatives.

    PubMed

    Pickles, K; Pirie, R S; Rhind, S; Dixon, P M; McGorum, B C

    2002-05-01

    Bronchoalveolar lavage fluid (BALF) samples are often subject to time delays, possibly with temperature fluctuations, between collection and processing. The aim of this study was to evaluate the effects of time, temperature and 2 different fixatives on equine BALF cytology, in order to develop guidelines for optimal equine BALF storage conditions. Total nucleated cell count (TCC), differential cell counts (DCC), absolute cell counts (ACC), cell viability, cell morphology and bacterial growth of BALF samples stored at 4, 18 (+/- addition of formalin- or alcohol-based fixatives) and 38 degrees C were monitored serially over a 72 h period. The time taken for a significant reduction in TCC and cell viability of unfixed BALF samples decreased as the storage temperature increased. There was no diagnostically significant difference in DCC or ACC over this time-course at any temperature. Unfixed BALF samples showed significant bacterial growth by 24 h at 4 degrees C, and 8 h at 18 and 38 degrees C; and poor morphology by 48 h at 4 degrees C, 24 h at 18 degrees C and 8 h at 38 degrees C. Fixed BALF samples showed poor morphology with Leishman's stain compared to unfixed samples.

  19. 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

  20. Fluid and rock interactions in silicate and aluminosilicate systems at elevated pressure and temperature

    NASA Astrophysics Data System (ADS)

    Davis, Mary Kathleen

    Understanding fluid chemistry in the subduction zone environment is key to unraveling the details of element transport from the slab to the surface. Solubilities of cations, such as silicon, in water strongly affect both the physical and chemical properties of supercritical metamorphic fluids. Modeling the thermodynamics of fluid-rock interactions requires therefore a profound understanding of cation dissolution and aqueous speciation. In situ Raman experiments of the silica-water, alumina-water, and alumina water systems were performed in an externally heated Bassett-type diamond-anvil cell at the Department of Geological Sciences, University of Michigan. Natural quartz samples and synthetic ruby samples were used in the experiments. Samples were loaded in the sample chamber with a water pressure medium. All experiments used rhenium gaskets of uniform thickness with a 500 mum drill hole for the sample chamber. Temperature was measured using K-type thermocouples encompassing both the upper and lower diamond anvils. Pressures are obtained on the basis of the Raman shift of the 464 cm-1 quartz mode where possible or the Raman shift of the tips of the diamond anvils according to a method developed in this work. This work characterizes the state of stress in the diamond anvil cell, which is used as the basis for the pressure calibration using only the diamond anvils. Raman measurements of silicate fluid confirm the presence of H4 SiO4 and H6Si2O7 in solution and expand the pressure range for in-situ structural observations in the silica-water system. Additionally, we identify the presence of another silica species present at mantle conditions, which occurs at long time scales in the diamond cell. This study provides the first in situ data in the alumina-water and alumina-silica-water systems at pressures and temperatures relevant to the slab environment. Al(OH) 3 appears to be the dominant form of alumina present under these conditions and in the alumina

  1. 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.

  2. 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.

  3. Fingerprinting the temperature and fluid source of fracture-filling calcite in geothermal systems using clumped isotopes

    NASA Astrophysics Data System (ADS)

    MacDonald, John M.; Davies, Amelia; Faithfull, John; Holdsworth, Chris; Newton, Michael; Williamson, Sam; John, Cedric

    2017-04-01

    Geothermal energy production relies on maintaining open fractures within the rock through which fluids can flow, but precipitation of minerals in fractures can modify and reduce fluid flow. Most geothermal fluids are rich in dissolved material, and readily precipitate minerals such as calcite within fracture systems. Such mineral deposition can be a key limiting factor in viable geothermal energy production. We need to better understand the relationship between fluid temperatures, mineral precipitation, and fracture filling in such systems. Clumped isotopes offer a new way of characterising the temperature and fluid source of fracture-filling calcite. This technique is based on the thermodynamic relationship between carbonate mineral growth temperature and the abundance of chemical bonding ("clumping") between 13C and 18O isotopes (expressed as Δ47) within single carbonate ions (e.g. Eiler, 2007). In the gas phase, isotopic exchange between CO2 molecules and water is continuous and so CO2 gas will record the ambient fluid temperature. When the CO2 is trapped in a solid mineral phase, the isotope ratio is fixed. As a result, clumped isotopes will record the temperature of crystallisation, enabling the application of clumped isotope palaeothermometry to a range of geological problems. Samples from active geothermal fields (the Kawerau geothermal field, New Zealand (McNamara et al., 2017)) and analogues to basaltic geothermal systems in Western Scotland have been analysed with clumped isotopes. We present petrography, δ13C and δ18O, and clumped isotope data from these samples to show how clumped isotopes can fingerprint the temperature and fluid source of fracture-filling calcite in geothermal systems. Having this understanding of fracture filling conditions can lead to focused development of remediation measures. References Eiler, J. M., 2007. EPSL 262(3-4), 309-327. McNamara, D. D., Lister, A., Prior, D. J., 2016. JVGR 323, 38-52.

  4. Onset of slugging criterion based on characteristics and stability analyses of transient one-dimensional two-phase flow equations of two-fluid model

    SciTech Connect

    Chun, M.H.; Sung, C.K.

    1996-07-01

    A two-step approach has been used to obtain a new criterion for the onset of slug formation: (1) In the first step, a more general expression than the existing models for the onset of slug flow criterion has been derived from the analysis of singular points and neutral stability conditions of the transient one-dimensional two-phase flow equations of two-fluid model. (2) In the second step, introducing simplifications and incorporating a parameter into the general expression obtained in the first step to satisfy a number of physical conditions a priori specified, a new simple criterion for the onset of slug flow has been derived. Comparisons of the present model with existing models and experimental data show that the present model agrees very closely with Taitel and Dukler`s model and experimental data in horizontal pipes. In an inclined pipe ({theta} = 50{degree}), however, the difference between the predictions of the present model and those of existing models is appreciably large and the present model gives the best agreement with Ohnuki et al.`s data.

  5. 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.

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

    PubMed

    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.

  7. 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.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

    Curbelo, J.; Mancho, A. M.

    2015-12-01

    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 is suitable for representing a very viscous lithosphere (and thus rather rigid) over a convecting mantle. To this end, we study a 2D convection problem in which viscosity depends on temperature by abruptly changing its value within a narrow temperature gap. Notable solutions are found for a sharp transition viscosity law which are fundamentally related to the presence of a symmetry in the problem. For instance, cyclic series are found consisting of spontaneous plate-like behaviors emerging sporadically through abrupt bursts, and rapidly evolving towards a stagnant lid regime. The plate-like evolution alternates motions towards either right or left, introducing temporary asymmetries on the convecting styles. Further time-dependent regimes with stagnant and plate-like lids are described, which are also greatly influenced by the presence of the symmetry. These results provide convection examples of moving plates, that coexist with subsurface upwards and downwards meandering jets, but without a proper subduction, and can be particularly illustrative for understanding convective styles of the Earth prior to subduction, or that of other planetary bodies.

  10. 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.

  11. Low temperature blocks fluid-phase pinocytosis and receptor-mediated endocytosis in Trypanosoma cruzi epimastigotes.

    PubMed

    de Figueiredo, R C; Soares, M J

    2000-05-01

    Gold-labeled albumin and transferrin were used to follow at the ultrastructural level the early events and the effect of low temperature on protein uptake by Trypanosoma cruzi epimastigotes. In parasites incubated for 5 min at 28 degrees C with protein-gold complexes, extracellular markers were found only at the cytostome and/or the flagellar pocket regions, whereas intracellular gold particles were detected inside small uncoated vesicles located nearby. Within 10 min, labeling was also observed in uncoated vesicles close to the nucleus. Only after 30 min could the tracers be detected in the reservosomes. Weak labeling in the cytostome and flagellar pocket of parasites incubated at 4 degrees C with the albumin-gold solution indicated that albumin uptake occurred by fluid-phase pinocytosis. On the other hand, intense labeling at the cytostome was observed in parasites incubated at 4 degrees C with gold-labeled transferrin, showing that receptor-mediated endocytosis occurs mainly at this site. Both proteins were absent from the cells at 4 degrees C and 12 degrees C. Raising the temperature from 12 degrees C to 28 degrees C led to transferrin labeling in intracellular vesicles dispersed throughout the cytoplasm, but not in reservosomes. Our results suggest that low temperatures affect the transport and pinching of endocytic vesicles as well as the rate of delivery of transferrin to reservosomes.

  12. Numerical studies of a confined volatile binary fluid subject to a horizontal temperature gradient

    NASA Astrophysics Data System (ADS)

    Qin, Tongran; Grigoriev, Roman

    2016-11-01

    Our fundamental understanding of convection in a layer of nonisothermal binary fluid with free surface in the presence of noncondensable gases, such as air, is still limited. In relatively thick liquid layers, the flow is driven by a combination of three different forces: buoyancy, thermocapillarity, and solutocapillarity in the liquid layer. Unlike buoyancy, both thermocapillarity and solutocapillarity depend sensitively on the boundary conditions at the liquid-vapor interface. Recent experimental studies showed that the composition of both the liquid and the gas phases have significant effects on the convection pattern. In particular, in a methanol-water mixture, four different flow regimes were identified on a map spanned by the concentration of methanol in the liquid and the concentration of air in the gas, which are thermocapillarity-dominated flow (TDF), solutocapillarity-dominated flow (SDF), unsteady flow (UF) and reversed flow (RF). This talk will present a comprehensive numerical model for a confined volatile binary fluid subject to a horizontal temperature gradient in the presence of noncondensable gases, and illustrate how the composition of both phases affect thermocapillarity and solutocapillarity. The numerical results will also be compared with experiments. Supported by NSF.

  13. 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

  14. TOPICAL REVIEW: Particle and fluid simulations of low-temperature plasma discharges: benchmarks and kinetic effects

    NASA Astrophysics Data System (ADS)

    Kim, H. C.; Iza, F.; Yang, S. S.; Radmilovic-Radjenovic, M.; Lee, J. K.

    2005-10-01

    Fluid, particle-in-cell and hybrid models are the numerical simulation techniques commonly used for simulating low-temperature plasma discharges. Despite the complexity of plasma systems and the challenges in describing and modelling them, well-organized simulation methods can provide physical information often difficult to obtain from experiments. Simulation results can also be used to identify research guidelines, find optimum operating conditions or propose novel designs for performance improvements. In this paper, we present an overview of the principles, strengths and limitations of the three simulation models, including a brief history and the recent status of their development. The three modelling techniques are benchmarked by comparing simulation results in different plasma systems (plasma display panels, capacitively coupled plasmas and inductively coupled plasmas) with experimentally measured data. In addition, different aspects of the electron and ion kinetics in these systems are discussed based upon simulation results.

  15. Two-phase working fluids for the temperature range 100-350 C. [in heat pipes for solar applications

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.; Tower, L.

    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 to 350 C have been identified, and reflux heat pipe tests initiated with 10 fluids and carbon steel and aluminum envelopes to experimentally establish corrosion behavior and noncondensable gas generation rates.

  16. 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.

  17. Global Stability for Thermal Convection in a Couple-Stress Fluid with Temperature and Pressure Dependent Viscosity

    NASA Astrophysics Data System (ADS)

    Sunil; Choudhary, Shalu; Bharti, P. K.

    2013-09-01

    We show that the global nonlinear stability threshold for convection in a couple-stress fluid with temperature and pressure dependent viscosity is exactly the same as the linear instability boundary. This optimal result is important because it shows that linearized instability theory has captured completely the physics of the onset of convection. It has also been found that the couplestress fluid is more stable than the ordinary viscous fluid and then the effect of couple-stress parameter (F) and variable dependent viscosity (Γ) on the onset of convection is also analyzed.

  18. 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.

  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. 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.

  1. 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.

  2. A study of the proteorhodopsin primary photoreaction by low-temperature FTIR difference and ultrafast transient infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Amsden, Jason J.

    Proteorhodopsin (PR), a newly discovered microbial rhodopsin found in marine proteobacteria, functions as a light-driven proton pump similar to bacteriorhodopsin (BR). PR-containing bacteria account for ˜13% of the microorganisms in the oceans' photic zone and are responsible for a significant fraction of the biosphere's solar energy conversion. We study the initial response of proteorhodopsin to photon absorption using a combination of low-temperature (80 K) Fourier transform infrared (FTIR) difference spectroscopy and ultrafast transient infrared (TIR) spectroscopy. Low-temperature FTIR difference spectroscopy combined with site-directed mutagenesis and isotope labeling is used to detect and characterize changes occurring in the conformation of the retinal chromophore, protein, and internal water molecules of green-absorbing PR (GPR) and blue-absorbing PR (BPR) during the initial phototransition. Measurements on cryogenically trapped intermediates do not accurately reflect all native structural changes occurring in PR and other microbial rhodopsins on ultrafast time scales at room temperature. Recent studies demonstrate that photoactive proteins such as photoactive yellow protein, myoglobin, and green-fluorescent protein, can react within several picoseconds to photon absorption by their chromophores. Faster subpicosecond protein responses have been suggested to occur in rhodopsin-like proteins where retinal chromophore photoisomerization may impulsively drive structural changes in nearby protein groups. Here, I test this possibility by investigating the earliest protein and chromophore structural changes occurring in GPR using ultrafast TIR spectroscopy with ˜200 fs time resolution combined with non-perturbing isotope labeling. On the basis of total-15N and retinal C15D (retinal with a deuterium on carbon 15) isotope labeling, the all-trans to 13-cis retinal chromophore isomerization occurs with a 500-700 fs time constant and the amide II mode of one or more

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. In situ measurement of dissolved chloride in high temperature hydrothermal fluids

    NASA Astrophysics Data System (ADS)

    Larson, B. I.; Olson, E. J.; Lilley, M. D.

    2007-05-01

    The ability to continuously monitor chemical properties of hydrothermal vent effluents for extended periods of time is essential to understanding dynamic processes responsible for the temporally variable nature of mid-ocean ridge hydrothermal systems. Although instruments do exist for some parameters, there has been no sensor capable of measuring the chloride concentration, an indicator of possible phase separation, on a real-time and long-term basis. In this article, we discuss the construction of a novel instrument which measures solution resistance as a proxy for chloride concentration. The sensor consists of four gold electrodes embedded in a cylindrical ZrO 2 ceramic housing. It has been successfully deployed in several high temperature vents at the Main Endeavour Field (MEF) on the Juan de Fuca ridge in the NE Pacific, and calibrated under simulated hydrothermal conditions ranging up to 380 °C and 300 bar. The in situ data clearly demonstrate a tidal influence on the effluent from some high temperature vents possibly relating to a subsurface mixing process involving non-seawater end-members. Non-tidal changes are used to constrain the sequence and type of controls operating on fluids circulating within the subsurface.

  8. Emergence of Coherent Localized Structures in Shear Deformations of Temperature Dependent Fluids

    NASA Astrophysics Data System (ADS)

    Katsaounis, Theodoros; Olivier, Julien; Tzavaras, Athanasios E.

    2017-04-01

    Shear localization occurs in various instances of material instability in solid mechanics and is typically associated with Hadamard-instability for an underlying model. While Hadamard instability indicates the catastrophic growth of oscillations around a mean state, it does not by itself explain the formation of coherent structures typically observed in localization. The latter is a nonlinear effect and its analysis is the main objective of this article. We consider a model that captures the main mechanisms observed in high strain-rate deformation of metals, and describes shear motions of temperature dependent non-Newtonian fluids. For a special dependence of the viscosity on the temperature, we carry out a linearized stability analysis around a base state of uniform shearing solutions, and quantitatively assess the effects of the various mechanisms affecting the problem: thermal softening, momentum diffusion and thermal diffusion. Then, we turn to the nonlinear model, and construct localized states—in the form of similarity solutions—that emerge as coherent structures in the localization process. This justifies a scenario for localization that is proposed on the basis of asymptotic analysis in Katsaounis and Tzavaras (SIAM J Appl Math 69:1618-1643, 2009).

  9. Emergence of Coherent Localized Structures in Shear Deformations of Temperature Dependent Fluids

    NASA Astrophysics Data System (ADS)

    Katsaounis, Theodoros; Olivier, Julien; Tzavaras, Athanasios E.

    2016-12-01

    Shear localization occurs in various instances of material instability in solid mechanics and is typically associated with Hadamard-instability for an underlying model. While Hadamard instability indicates the catastrophic growth of oscillations around a mean state, it does not by itself explain the formation of coherent structures typically observed in localization. The latter is a nonlinear effect and its analysis is the main objective of this article. We consider a model that captures the main mechanisms observed in high strain-rate deformation of metals, and describes shear motions of temperature dependent non-Newtonian fluids. For a special dependence of the viscosity on the temperature, we carry out a linearized stability analysis around a base state of uniform shearing solutions, and quantitatively assess the effects of the various mechanisms affecting the problem: thermal softening, momentum diffusion and thermal diffusion. Then, we turn to the nonlinear model, and construct localized states—in the form of similarity solutions—that emerge as coherent structures in the localization process. This justifies a scenario for localization that is proposed on the basis of asymptotic analysis in uc(Katsaounis) and uc(Tzavaras) (SIAM J Appl Math 69:1618-1643, 2009).

  10. Thermoregulation During Extended Exercise in the Heat: Comparisons of Fluid Volume and Temperature.

    PubMed

    Hailes, Walter S; Cuddy, John S; Cochrane, Kyle; Ruby, Brent C

    2016-09-01

    This study aimed to determine the physiological and thermoregulatory responses of individuals exercising in the heat (US military red flag conditions, wet-bulb globe temperature 31.5-32.2ºC) while consuming varied volumes of ambient temperature water and ice slurry. Participants (N = 12) walked on a treadmill for 3 hours at approximately 40% peak aerobic capacity in a hot environment while consuming ambient temperature (35.5°C) water (W), ice slurry (0°C, two-thirds shaved ice and one-third water) at a ratio of 2 g·kg(-1) body mass every 10 minutes (FS), and reduced volume ice slurry as described at a rate of 1 g·kg(-1) body mass every 10 minutes (HS). Trials were completed at least 14 days apart, in a randomized, repeated measures design. Percent body weight loss was higher during the HS trial (1.8 ± 0.01%) compared with FS (0.5 ± 0.01%; P < .001) and W (0.6 ± 0.01%; P < .001). Mean rectal temperature at 3 hours was lower during FS (37.8 ± 0.7°C) compared with HS (38.1 ± 0.8°C) and W (38.2 ± 0.8°C) (P = .04 vs HS, and P = .005 vs W, main effect for trial). No differences were found in rectal temperature between HS and W. Heart rate was lower at the end of the third hour during FS (141 ± 10 beats/min) compared with HS (157 ± 19 beats/min) and W (154 ± 18 beats/min) (P = .001 and P = .007, respectively, time × trial interaction). There were no differences in heart rate between HS and W. The temperature of consumed fluids may be as important as the volume for the management of thermoregulation and other physiological responses for extended work in hot environments. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  11. 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.

  12. 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.

  13. Valve assembly for use with high temperature and high pressure fluids

    DOEpatents

    De Feo, Angelo

    1982-01-01

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

  14. Temperature dependence of the hydrated electron's excited-state relaxation. II. Elucidating the relaxation mechanism through ultrafast transient absorption and stimulated emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Farr, Erik P.; Zho, Chen-Chen; Challa, Jagannadha R.; Schwartz, Benjamin J.

    2017-08-01

    The structure of the hydrated electron, particularly whether it exists primarily within a cavity or encompasses interior water molecules, has been the subject of much recent debate. In Paper I [C.-C. Zho et al., J. Chem. Phys. 147, 074503 (2017)], we found that mixed quantum/classical simulations with cavity and non-cavity pseudopotentials gave different predictions for the temperature dependence of the rate of the photoexcited hydrated electron's relaxation back to the ground state. In this paper, we measure the ultrafast transient absorption spectroscopy of the photoexcited hydrated electron as a function of temperature to confront the predictions of our simulations. The ultrafast spectroscopy clearly shows faster relaxation dynamics at higher temperatures. In particular, the transient absorption data show a clear excess bleach beyond that of the equilibrium hydrated electron's ground-state absorption that can only be explained by stimulated emission. This stimulated emission component, which is consistent with the experimentally known fluorescence spectrum of the hydrated electron, decreases in both amplitude and lifetime as the temperature is increased. We use a kinetic model to globally fit the temperature-dependent transient absorption data at multiple temperatures ranging from 0 to 45 °C. We find the room-temperature lifetime of the excited-state hydrated electron to be 137 ±40 fs, in close agreement with recent time-resolved photoelectron spectroscopy (TRPES) experiments and in strong support of the "non-adiabatic" picture of the hydrated electron's excited-state relaxation. Moreover, we find that the excited-state lifetime is strongly temperature dependent, changing by slightly more than a factor of two over the 45 °C temperature range explored. This temperature dependence of the lifetime, along with a faster rate of ground-state cooling with increasing bulk temperature, should be directly observable by future TRPES experiments. Our data also suggest

  15. 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.

  16. High temperature deformation and fluid enhanced zircon modification along an exhumed subduction megathrust

    NASA Astrophysics Data System (ADS)

    Chapman, A. D.; Saleeby, J.

    2010-12-01

    metamorphic fluids resulted in significant zircon isotopic resetting. The observations presented here indicate that the San Emigdio Schist was deposited within a narrow time interval after ca. 108 Ma and upper structural levels experienced a Pb loss event at ca. 94 Ma during underthrusting beneath the then recently active Late Cretaceous arc. Continued schist underplating led to refrigeration of the upper plate and relaxation of the initially high geothermal gradient, explaining the lack of evidence for Pb loss at deep structural levels. We postulate that some combination of high temperatures, deformation, and fluid infiltration adjacent to the Rand fault triggered this Pb loss episode.

  17. Properties of molecular solids and fluids at high pressure and temperatures. Progress report, July 1, 1989--July 1, 1992

    SciTech Connect

    Etters, R.D.

    1992-03-01

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

  18. Unsteady MHD free convection flow of rotating Jeffrey fluid embedded in a porous medium with ramped wall temperature

    NASA Astrophysics Data System (ADS)

    Zin, N. A. Mohd; Khan, I.; Shafie, S.

    2017-09-01

    The effect of radiative heat transfer on unsteady magnetohydrodynamic (MHD) free convection flow of rotating Jeffrey fluid past an infinite vertical plate saturated in a porous medium with ramped wall temperature is investigated. The incompressible fluid is taken electrically conducting under influence of transverse magnetic field which perpendicular to the flow. An appropriate dimensionless variables are employed to the governing equations and solved analytically by Laplace transform technique. The results of several controlling parameters for both ramped wall temperature and an isothermal plate are presented graphically with comprehensive discussions. It has been observed that, an increase in rotation parameter, reduced the primary velocity, but an opposite behaviour is noticed for the secondary velocity. Moreover, large values of Hartmann number tends to retard the fluid flow due to the Lorentz force.

  19. 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.

  20. Computational fluid dynamics analysis and experimental study of a low measurement error temperature sensor used in climate observation

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Liu, Qingquan; Dai, Wei

    2017-02-01

    To improve the air temperature observation accuracy, a low measurement error temperature sensor is proposed. A computational fluid dynamics (CFD) method is implemented to obtain temperature errors under various environmental conditions. Then, a temperature error correction equation is obtained by fitting the CFD results using a genetic algorithm method. The low measurement error temperature sensor, a naturally ventilated radiation shield, a thermometer screen, and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated platform served as an air temperature reference. The mean temperature errors of the naturally ventilated radiation shield and the thermometer screen are 0.74 °C and 0.37 °C, respectively. In contrast, the mean temperature error of the low measurement error temperature sensor is 0.11 °C. The mean absolute error and the root mean square error between the corrected results and the measured results are 0.008 °C and 0.01 °C, respectively. The correction equation allows the temperature error of the low measurement error temperature sensor to be reduced by approximately 93.8%. The low measurement error temperature sensor proposed in this research may be helpful to provide a relatively accurate air temperature result.

  1. Computational fluid dynamics analysis and experimental study of a low measurement error temperature sensor used in climate observation.

    PubMed

    Yang, Jie; Liu, Qingquan; Dai, Wei

    2017-02-01

    To improve the air temperature observation accuracy, a low measurement error temperature sensor is proposed. A computational fluid dynamics (CFD) method is implemented to obtain temperature errors under various environmental conditions. Then, a temperature error correction equation is obtained by fitting the CFD results using a genetic algorithm method. The low measurement error temperature sensor, a naturally ventilated radiation shield, a thermometer screen, and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated platform served as an air temperature reference. The mean temperature errors of the naturally ventilated radiation shield and the thermometer screen are 0.74 °C and 0.37 °C, respectively. In contrast, the mean temperature error of the low measurement error temperature sensor is 0.11 °C. The mean absolute error and the root mean square error between the corrected results and the measured results are 0.008 °C and 0.01 °C, respectively. The correction equation allows the temperature error of the low measurement error temperature sensor to be reduced by approximately 93.8%. The low measurement error temperature sensor proposed in this research may be helpful to provide a relatively accurate air temperature result.

  2. 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.

  3. Sensitivity analysis of effective fluid and rock bulk modulus due to changes in pore pressure, temperature and saturation

    NASA Astrophysics Data System (ADS)

    Bhakta, Tuhin; Avseth, Per; Landrø, Martin

    2016-12-01

    Fluid substitution plays a vital role in time-lapse seismic modeling and interpretation. It is, therefore, very important to quantify as exactly as possible the changes in fluid bulk modulus due to changes in reservoir parameters. In this paper, we analyze the sensitivities in effective fluid bulk modulus due to changes in reservoir parameters like saturation, pore-pressure and temperature. The sensitivities are analyzed for two extreme bounds, i.e. the Voigt average and the Reuss average, for various fluid combinations (i.e. oil-water, gas-water and gas-oil). We quantify that the effects of pore-pressure and saturation changes are highest in the case of gas-water combination, while the effect of temperature is highest for oil-gas combination. Our results show that sensitivities vary with the bounds, even for same amount of changes in any reservoir parameter. In 4D rock physics studies, we often neglect the effects of pore-pressure or temperature changes assuming that those effects are negligible compare to the effect due to saturation change. Our analysis shows that pore-pressure and temperature changes can be vital and sometimes higher than the effect of saturation change. We investigate these effects on saturated rock bulk modulus. We first compute frame bulk modulus using the Modified Hashin Shtrikman (MHS) model for carbonate rocks and then perform fluid substitution using the Gassmann equation. We consider upper bound of the MHS as elastic behavior for stiffer rocks and lower bound of the MHS as elastic behavior for softer rocks. We then investigate four various combinations: stiff rock with upper bound (the Voigt bound) as effective fluid modulus, stiff rock with lower bound (Reuss bound) as effective fluid modulus, soft rock with upper bound as effective fluid modulus and soft rock with lower bound as effective fluid modulus. Our results show that the effect of any reservoir parameter change is highest for soft rock and lower bound combination and lowest

  4. 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

  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. 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.

  7. Convective heat transport in compressible fluids.

    PubMed

    Furukawa, Akira; Onuki, Akira

    2002-07-01

    We present hydrodynamic equations of compressible fluids in gravity as a generalization of those in the Boussinesq approximation used for nearly incompressible fluids. They account for adiabatic processes taking place throughout the cell (the piston effect) and those taking place within plumes (the adiabatic temperature gradient effect). Performing two-dimensional numerical analysis, we reveal some unique features of plume generation and convection in transient and steady states of compressible fluids. As the critical point is approached, the overall temperature changes induced by plume arrivals at the boundary walls are amplified, giving rise to overshoot behavior in transient states and significant noise in the temperature in steady states. The velocity field is suggested to assume a logarithmic profile within boundary layers. Random reversal of macroscopic shear flow is examined in a cell with unit aspect ratio. We also present a simple scaling theory for moderate Rayleigh numbers.

  8. Low and high temperature drilling fluids based on sulfonated terpolymer ionomers

    SciTech Connect

    Peiffer, D. G.; Lundberg, R. D.; Pober, K. W.

    1985-08-27

    The present invention relates to sulfonated thermoplastic terpolymers which are terpolymers of t-butyl styrene, styrene and sodium styrene sulfonate wherein these sulfonated terpolymers function as viscosification agents when added to oil-based drilling muds which are the fluids used to maintain pressure, cool drill bits and lift cuttings from the holes in the drilling operation for oil and gas wells. The sulfonated thermoplastic terpolymer of the latex have about 5 to 100 meg. of sulfonate groups per 100 grams of the sulfonated thermoplastic terpolymer, wherein the sulfonated groups are neutralized with a metallic cation or an amine or ammonium counterion. A polar cosolvent can optionally be added to the mixture of oil drilling mud and sulfonated thermoplastic polymer, wherein the polar cosolvent increases the solubility of the sulfonated thermoplastic terpolymer in the oil drilling mud by decreasing the strong ionic interactions between the sulfonate groups of the sulfonated polymer. The drilling muds formed from these latices of the sulfonated thermpolastic terpolymers exhibits markedly improved low and high temperature rheological properties as compared to drilling muds formed from sulfonated thermoplastic copolymers.

  9. An automated system for performing continuous viscosity versus temperature measurements of fluids using an Ostwald viscometer

    NASA Astrophysics Data System (ADS)

    Beaulieu, L. Y.; Logan, E. R.; Gering, K. L.; Dahn, J. R.

    2017-09-01

    An automated system was developed to measure the viscosity of fluids as a function of temperature using image analysis tracking software. An Ostwald viscometer was placed in a three-wall dewar in which ethylene glycol was circulated using a thermal bath. The system collected continuous measurements during both heating and cooling cycles exhibiting no hysteresis. The use of video tracking analysis software greatly reduced the measurement errors associated with measuring the time required for the meniscus to pass through the markings on the viscometer. The stability of the system was assessed by performing 38 consecutive measurements of water at 42.50 ± 0.05 °C giving an average flow time of 87.7 ± 0.3 s. A device was also implemented to repeatedly deliver a constant volume of liquid of 11.00 ± 0.03 ml leading to an average error in the viscosity of 0.04%. As an application, the system was used to measure the viscosity of two Li-ion battery electrolyte solvents from approximately 10 to 40 °C with results showing excellent agreement with viscosity values calculated using Gering's Advanced Electrolyte Model (AEM).

  10. Fluid simulations of mirror constraints on proton temperature anisotropy in solar wind turbulence

    NASA Astrophysics Data System (ADS)

    Laveder, D.; Marradi, L.; Passot, T.; Sulem, P. L.

    2011-09-01

    Non-resonant ion perpendicular heating by low-frequency kinetic Alfvén wave turbulence, together with the constraining effect of the mirror instability on the developing temperature anisotropy observed in the solar wind, are simulated for the first time in a self-consistent way using a fluid model retaining low-frequency kinetic effects. This model which does not include solar wind expansion, concentrates on the influence of small-scale turbulence. It provides a sufficiently refined description of Landau damping and finite Larmor corrections to accurately capture the transverse dynamics at sub-ionic scales, including the self-regulating influence of the developing mirror modes. A fit of the simulation results with the usual mirror-instability threshold is obtained, reproducing the frontier of the slow solar wind WIND/SWE data in the (T$\\perp$i/T$\\parallel$i, β$\\parallel$i) diagram. The quality of the fit is improved in the presence of a small amount of collisions, which suggests that the deviations from bi-Maxwellianity in the slow solar wind are weak enough not to significantly affect the mirror threshold.

  11. 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.

  12. Branching points in the low-temperature dipolar hard sphere fluid.

    PubMed

    Rovigatti, Lorenzo; Kantorovich, Sofia; Ivanov, Alexey O; Tavares, José Maria; Sciortino, Francesco

    2013-10-07

    In this contribution, we investigate the low-temperature, low-density behaviour of dipolar hard-sphere (DHS) particles, i.e., hard spheres with dipoles embedded in their centre. We aim at describing the DHS fluid in terms of a network of chains and rings (the fundamental clusters) held together by branching points (defects) of different nature. We first introduce a systematic way of classifying inter-cluster connections according to their topology, and then employ this classification to analyse the geometric and thermodynamic properties of each class of defects, as extracted from state-of-the-art equilibrium Monte Carlo simulations. By computing the average density and energetic cost of each defect class, we find that the relevant contribution to inter-cluster interactions is indeed provided by (rare) three-way junctions and by four-way junctions arising from parallel or anti-parallel locally linear aggregates. All other (numerous) defects are either intra-cluster or associated to low cluster-cluster interaction energies, suggesting that these defects do not play a significant part in the thermodynamic description of the self-assembly processes of dipolar hard spheres.

  13. The steady-state and transient electron transport within bulk zinc-blende indium nitride: The impact of crystal temperature and doping concentration variations

    SciTech Connect

    Siddiqua, Poppy; O'Leary, Stephen K.

    2016-03-07

    Within the framework of a semi-classical three-valley Monte Carlo electron transport simulation approach, we analyze the steady-state and transient aspects of the electron transport within bulk zinc-blende indium nitride, with a focus on the response to variations in the crystal temperature and the doping concentration. We find that while the electron transport associated with zinc-blende InN is highly sensitive to the crystal temperature, it is not very sensitive to the doping concentration selection. The device consequences of these results are then explored.

  14. The transient thermal response of a tubular solar collector

    NASA Technical Reports Server (NTRS)

    Lansing, F. L.

    1976-01-01

    A special analytical solution is provided for the timewise response of the circulating fluid temperatures when a sudden step change of the input solar radiation is imposed and remains constant thereafter. An example which demonstrates the transient temperatures at the exit section of a single collector with two different flow patterns is presented. This study is used to supplement some numerical solutions to provide a fairly complete coverage for this type of solar collector.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  16. One-dimensional modeling of radial heat removal during depressurized heatup transients in modular pebble-bed and prismatic high temperature gas-cooled reactors

    SciTech Connect

    Savage, M.G.

    1984-07-01

    A one-dimensional computational model was developed to evaluate the heat removal capabilities of both prismatic-core and pebble-bed modular HTGRs during depressurized heatup transients. A correlation was incorporated to calculate the temperature- and neutron-fluence-dependent thermal conductivity of graphite. The modified Zehner-Schluender model was used to determine the effective thermal conductivity of a pebble bed, accounting for both conduction and radiation. Studies were performed for prismatic-core and pebble-bed modular HTGRs, and the results were compared to analyses performed by GA and GR, respectively. For the particular modular reactor design studied, the prismatic HTGR peak temperature was 2152.2/sup 0/C at 38 hours following the transient initiation, and the pebble-bed peak temperature was 1647.8/sup 0/C at 26 hours. These results compared favorably with those of GA and GE, with only slight differences caused by neglecting axial heat transfer in a one-dimensional radial model. This study found that the magnitude of the initial power density had a greater effect on the temperature excursion than did the initial temperature.

  17. 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.

  18. 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

  19. 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

  20. Diagnostic system for measuring temperature, pressure, CO2 concentration and H2O concentration in a fluid stream

    DOEpatents

    Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji-Hyung; Parks, II, James E.

    2017-01-10

    A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperatures derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.