WorldWideScience

Sample records for cryogenic flow sensor

  1. A Cryogenic Flow Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Technologies Group, Inc. proposes the development of a Cryogenic Flow Sensor (CFS) for determining mass flow of cryogens in spacecraft propellant...

  2. A Cryogenic Flow Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on the success of the phase I effort, Advanced Technologies Group, Inc. proposes the development of a Cryogenic Flow Sensor (CFS) for determining mass flow of...

  3. Dual Cryogenic Capacitive Density Sensor

    Science.gov (United States)

    Youngquist, Robert; Mata, Carlos; Vokrot, Peter; Cox, Robert

    2009-01-01

    A dual cryogenic capacitive density sensor has been developed. The device contains capacitive sensors that monitor two-phase cryogenic flow density to within 1% accuracy, which, if temperature were known, could be used to determine the ratio of liquid to gas in the line. Two of these density sensors, located a known distance apart, comprise the sensor, providing some information on the velocity of the flow. This sensor was constructed as a proposed mass flowmeter with high data acquisition rates. Without moving parts, this device is capable of detecting the density change within a two-phase cryogenic flow more than 100 times a second. Detection is enabled by a series of two sets of five parallel plates with stainless steel, cryogenically rated tubing. The parallel plates form the two capacitive sensors, which are measured by electrically isolated digital electronics. These capacitors monitor the dielectric of the flow essentially the density of the flow and can be used to determine (along with temperature) the ratio of cryogenic liquid to gas. Combining this information with the velocity of the flow can, with care, be used to approximate the total two-phase mass flow. The sensor can be operated at moderately high pressures and can be lowered into a cryogenic bath. The electronics have been substantially improved over the older sensors, incorporating a better microprocessor, elaborate ground loop protection and noise limiting circuitry, and reduced temperature sensitivity. At the time of this writing, this design has been bench tested at room temperature, but actual cryogenic tests are pending

  4. Cryogenic MEMS Pressure Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A directly immersible cryogenic MEMS pressure sensor will be developed. Each silicon die will contain a vacuum-reference and a tent-like membrane. Offsetting thermal...

  5. Continuous-Reading Cryogen Level Sensor

    Science.gov (United States)

    Barone, F. E.; Fox, E.; Macumber, S.

    1984-01-01

    Two pressure transducers used in system for measuring amount of cryogenic liquid in tank. System provides continuous measurements accurate within 0.03 percent. Sensors determine pressure in liquid and vapor in tank. Microprocessor uses pressure difference to compute mass of cryogenic liquid in tank. New system allows continuous sensing; unaffected by localized variations in composition and density as are capacitance-sensing schemes.

  6. Optical density measurements in a multiphase cryogenic fluid flow system

    Science.gov (United States)

    Korman, Valentin; Wiley, John; Gregory, Don A.

    2006-05-01

    An accurate determination of fluid flow in a cryogenic propulsion environment is difficult under the best of circumstances. The extreme thermal environment increases the mechanical constraints, and variable density conditions create havoc with traditional flow measurement schemes. Presented here are secondary results of cryogenic testing of an all-optical sensor capable of a mass flow measurement by directly interrogating the fluid's density state and a determination of the fluid's velocity. The sensor's measurement basis does not rely on any inherent assumptions as to the state of the fluid flow (density or otherwise). The fluid sensing interaction model will be discussed. Current test and evaluation data and future development work will be presented.

  7. Thermal flow micro sensors

    OpenAIRE

    Elwenspoek, M.

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow sensors and time of flight flow sensors. Anemometers may comprise several heaters and temperature sensors and from a geometric point of view are similar sometimes for calorimetric flow sensors. We fi...

  8. CRYOGENIC SYSTEM FOR PRECISE CALIBRATION OF TEMPERATURE SENSORS

    Directory of Open Access Journals (Sweden)

    A. N. Solovyev

    2016-09-01

    Full Text Available A calibration technique for cryogenic temperature sensors is proposed and implemented. The experimental setup is based on the helium cryogenerator, providing calibration of the temperature sensors of various types in wide temperature range, including cryogenic band (25-100K. A condensation thermometer with hydrogen, neon, argon and xenon as working gases is used as a reference sensor. The experimental setup was successfully used for precise (0.1K precision calibration of platinum resistive temperature detectors (Pt-100 for international nuclear physics experiments MuSun and PolFusion. The setup can also be used for calibration of temperature sensors of the other types.

  9. Cryogenic detector modules and edgeless silicon sensors

    Energy Technology Data Exchange (ETDEWEB)

    Rouby, X. [Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium)]. E-mail: rouby@fynu.ucl.ac.be; Eremin, V. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Grohmann, S. [ILK Dresden, Bertolt-Brecht-Allee 20, D-01309 Dresden (Germany); Haerkoenen, J. [Helsinki Institute of Physics, 00014 Helsinki (Finland); Li, Z. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Luukka, P. [Helsinki Institute of Physics, 00014 Helsinki (Finland); Militaru, O. [Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Niinikoski, T. [CERN, CH-1211 Geneva (Switzerland); Nuessle, G. [CERN, CH-1211 Geneva (Switzerland); Perea Solano, B. [CERN, CH-1211 Geneva (Switzerland); Piotrzkowski, K. [Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Tuovinen, E. [Helsinki Institute of Physics, 00014 Helsinki (Finland); Verbitskaya, E. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

    2007-01-11

    We are studying the operation of silicon microstrip detector with readout electronics in the temperature range from 90 to 130K. The sensor can be operated in the current-injection mode which significantly improves its radiation hardness. A first module prototype has been built, with APV25 readout chips and an embedded microtube, providing efficient low-mass cooling of the whole module with a two-phase flow of N{sub 2} or Ar. First pedestal and pulse shape temperature dependencies are presented for this module. We have also built an edgeless test module with two pairs of laser cut sensors, with both angular and parallel cuts with respect to the strips (at 120{mu}m pitch). We are studying the efficiency of the microstrip sensors very close (<200{mu}m) to the physical border of the cut silicon crystal and present here some electrical characteristics.

  10. Thermal flow micro sensors

    NARCIS (Netherlands)

    Elwenspoek, M.

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow se

  11. A standardized Cernox™ cryogenic temperature sensor for aerospace applications

    Science.gov (United States)

    Courts, Samuel Scott

    2014-11-01

    The success of any aerospace mission depends upon the reliability of the discrete components comprising the instrument. To this end, many test standards have been developed to define test protocols and methods for the parts used in these missions. To date, no recognized MIL-type standard exists for cryogenic temperature sensors that are used from room temperature to 20 K or below. The aerospace applications utilizing these sensors require the procuring entity to develop a specification which the sensor manufacturer uses to screen and qualify a single build lot for flight use. The individual applications often require only a small number of sensors with the end result being a relatively high cost and long delivery time. Over the past two decades, Lake Shore Cryotronics, Inc. has worked with many aerospace companies to supply Cernox™ cryogenic temperature sensors for numerous missions. The experience gained from this work has led to the development of a manufacturing and test protocol resulting in 'off-the-shelf' cryogenic temperature sensors that should meet the requirements for many aerospace applications. Sensors will be available at the base part level with the ability to configure the delivered part with regard to lead wire material, package adapter, lead wire extensions, and calibration as appropriate or necessary for the application. This work presents details of this manufacturing, inspection, and test protocol as well as performance characteristics of Cernox™ temperature sensors when inspected and tested to this protocol.

  12. High-Speed Thermal Characterization of Cryogenic Flows Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna proposes to continue development on a high-speed fiber optic sensor and readout system for cryogenic temperature measurements in liquid oxygen (LOX) and liquid...

  13. GaAs JFETs for Extremely Low-Noise, Deep Cryogenic Sensor Readout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Ultrasensitive sensors used in NASAs scientific missions (for example infrared sensors) typically require operation at deep cryogenic temperatures for optimum...

  14. Optical fibre temperature sensor in the cryogenic range

    NARCIS (Netherlands)

    Bertrand, S.; Jalocha, A.; Tribillon, G.; Bouazaoui, M.; Rouhet, J.

    1996-01-01

    The realization of an optical fibre sensor applied to cryogenic temperature measurement in harsh environments is presented. The measurement principle is based on the analysis of the decay-time of the fluorescence emitted by special doped crystals, the excited state lifetimes of which are greatly dep

  15. Single Wall Carbon Nanotubes Based Cryogenic Temperature Sensor Platforms.

    Science.gov (United States)

    Monea, Bogdan Florian; Ionete, Eusebiu Ilarian; Spiridon, Stefan Ionut; Leca, Aurel; Stanciu, Anda; Petre, Emil; Vaseashta, Ashok

    2017-09-10

    We present an investigation consisting of single walled carbon nanotubes (SWCNTs) based cryogenic temperature sensors, capable of measuring temperatures in the range of 2-77 K. Carbon nanotubes (CNTs) due to their extremely small size, superior thermal and electrical properties have suggested that it is possible to create devices that will meet necessary requirements for miniaturization and better performance, by comparison to temperature sensors currently available on the market. Starting from SWCNTs, as starting material, a resistive structure was designed. Employing dropcast method, the carbon nanotubes were deposited over pairs of gold electrodes and in between the structure electrodes from a solution. The procedure was followed by an alignment process between the electrodes using a dielectrophoretic method. Two sensor structures were tested in cryogenic field down to 2 K, and the resistance was measured using a standard four-point method. The measurement results suggest that, at temperatures below 20 K, the temperature coefficient of resistance average for sensor 1 is 1.473%/K and for sensor 2 is 0.365%/K. From the experimental data, it can be concluded that the dependence of electrical resistance versus temperature can be approximated by an exponential equation and, correspondingly, a set of coefficients are calculated. It is further concluded that the proposed approach described here offers several advantages, which can be employed in the fabrication of a microsensors for cryogenic applications.

  16. Pulse Tube Interference in Cryogenic Sensor Resonant Circuits - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Tyler [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    Transition edge sensors (TES) are extremely sensitive superconducting sensors, operating at 100 mK, which can be used to detect X-rays and Cosmic Microwave Background. The goal of our project is to design the electronics to read out an array of 10000 of these sensors by using microwave signals. However, we noticed the pulse tube used to maintain cryogenic temperatures caused interference in our readout. To determine the cause of the signal distortions, we used a detector with a 370 MHz sampling rate to collect and analyze sensor data. Although this data provided little information towards the nature of the noise, it was determined through a maintenance procedure than the 0.3 mm stainless steel wires were being vibrated due to acoustic waves, which distorted the signal. Replacing this wire appeared to cease the interference from the sensor data.

  17. Biomimetic Flow Sensors

    NARCIS (Netherlands)

    Casas, J.; Liu, Chang; Krijnen, G.J.M.

    2012-01-01

    Biomimetic flow sensors are biologically inspired devices that measure the speed and direction of fluids. This survey starts by describing the role and functioning of airflow-sensing hairs in arthropods and in fishes, carries on with the biomimetic MEMS implementations, both for air and water flow s

  18. Recent Developments and Qualification of Cryogenic Helium Flow Meters

    CERN Document Server

    Bézaguet, Alain-Arthur; Serio, L

    2002-01-01

    Flow measurement of cryogenic fluids is a useful diagnostic tool not only to assess thermal performance of superconducting devices and related components but also for early diagnosis of faulty components/systems and to assure the correct sharing of cryogenic power. It is mainly performed on the recovery at room temperature of vapor from liquid boil-off due to lack of commercially available robust and precise cryogenic mass flow meters. When high-accuracy or fast-time response is needed, or individual gas recovery at room temperature is not available, it is necessary to measure directly the fluid feed at cryogenic temperature. The results of extensive testing of industrially available and in-house developed flowmeters outlining characteristics and advantages of each measuring method are presented.

  19. Conference on Refrigeration for Cryogenic Sensors and Electronic Systems

    CERN Document Server

    Sullivan, D B; McCarthy, S E; Cryogenic Refrigeration Conference; International Cryocooler Conference; Cryocoolers 1

    1981-01-01

    This proceedings documents the output of a meeting of refrigeration specialists held at the National Bureau of Standards, Boulder, CO, on October 6 and 7, 1980. Building on an earlier invitation-only meeting in 1977, the purpose of this first open meeting was to discuss progress in the development of refrigeration systems to cool cryogenic sensors and electronic systems in the temperature range below 20 K and with required cooling capacities below 10 W. The meeting was jointly sponsored by the International Institute of Refrigeration - Commission A1/2, the Office of Naval Research, the Naval Research Laboratory, the Cryogenic Engineering Conference, and the National Bureau of Standards. This first open cryocooler conference consisted of 23 papers presented by representatives of industry, government, and academia. The conference proceedings reproduced here was published by the National Bureau of Standards in Boulder, Colorado as NBS Special Publication #607. Subsequent meetings would become known as the Intern...

  20. Cryogenic Heat Exchanger with Turbulent Flows

    Science.gov (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  1. Cryogenic Heat Exchanger with Turbulent Flows

    Science.gov (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard

    2012-01-01

    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  2. Analytical network model on the flow and thermal characteristics of cyclic flow cryogenic regenerators

    Science.gov (United States)

    Hua, Xiao Jia; Zhong, Guo Fang

    1988-11-01

    The flow and thermal characteristics of rapid cyclic flow cryogenic regenerators and their interrelationship have been analysed using the linear network theory and perturbation method. The effect of flow resistance, gas storage in void volume, temperature distribution, interaction of pressure wave and cyclic mass flow, and the factor of real gas were considered. A computer simulation program, CFCRX, was developed and the numerical results obtained are presented. This theory provides a better understanding of the working mechanism of cryogenic regenerators.

  3. Measurement of cryogenic regenerator characteristics under oscillating flow and pulsating pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kwanwoo Nam; Sangkwon Jeong [Korea Advanced Institute of Science and Technology, Daejon (Korea). Department of Mechanical Engineering, Cryogenic Engineering Laboratory

    2003-11-01

    This paper describes an experimental apparatus developed to investigate detailed thermal and hydrodynamic characteristics of a regenerator at cryogenic temperature under oscillating flow and pulsating pressure conditions. Cold-end of the regenerator is maintained at approximately 85 K for G-M cryocooler type and 100 K for Stirling cryocooler type operations by means of two cryogenic heat exchangers. At both ends of the regenerator, fine hot wire probes are installed to measure the fast oscillating gas temperature and mass flow rate. The gas temperature sensors installed very close to the ends of the regenerator matrix assure precise gas temperature measurement in the regenerator. In this study, thermal and hydrodynamic behaviors of the well-defined wire-screen regenerator are fully characterized. First, pressure drop characteristics are discussed for different frequencies under room temperature. Second, ineffectiveness of the regenerator is obtained for different cold-end temperatures. (author)

  4. Measurement of cryogenic regenerator characteristics under oscillating flow and pulsating pressure

    Science.gov (United States)

    Nam, Kwanwoo; Jeong, Sangkwon

    2003-10-01

    This paper describes an experimental apparatus developed to investigate detailed thermal and hydrodynamic characteristics of a regenerator at cryogenic temperature under oscillating flow and pulsating pressure conditions. Cold-end of the regenerator is maintained at approximately 85 K for G-M cryocooler type and 100 K for Stirling cryocooler type operations by means of two cryogenic heat exchangers. At both ends of the regenerator, fine hot wire probes are installed to measure the fast oscillating gas temperature and mass flow rate. The gas temperature sensors installed very close to the ends of the regenerator matrix assure precise gas temperature measurement in the regenerator. In this study, thermal and hydrodynamic behaviors of the well-defined wire-screen regenerator are fully characterized. First, pressure drop characteristics are discussed for different frequencies under room temperature. Second, ineffectiveness of the regenerator is obtained for different cold-end temperatures.

  5. A Novel Flow Measurement System for Cryogenic Two-Phase Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flow rate measurements for cryogenic propellants are required for spacecraft and space exploration systems. Such a requirement has been hampered by lack of fast and...

  6. Passive Wireless Cryogenic Liquid Level Sensors Using Orthogonal Frequency Coded Acoustic Wave Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the continued development of passive wireless surface acoustic wave (SAW) based liquid level sensors for NASA application to cryogenic liquid...

  7. Passive Wireless Cryogenic Liquid Level Sensors Using Orthogonal Frequency Coded Acoustic Wave Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of passive wireless surface acoustic wave (SAW) based liquid level sensors for NASA application to cryogenic liquid level...

  8. Cryogenic fiber optic temperature sensor and method of manufacturing the same

    Science.gov (United States)

    Kochergin, Vladimir (Inventor)

    2012-01-01

    This invention teaches the fiber optic sensors temperature sensors for cryogenic temperature range with improved sensitivity and resolution, and method of making said sensors. In more detail, the present invention is related to enhancement of temperature sensitivity of fiber optic temperature sensors at cryogenic temperatures by utilizing nanomaterials with a thermal expansion coefficient that is smaller than the thermal expansion coefficient of the optical fiber but larger in absolute value than the thermal expansion coefficient of the optical fiber at least over a range of temperatures.

  9. Computational Analyses of Cavitating Flows in Cryogenic Liquid Hydrogen

    Institute of Scientific and Technical Information of China (English)

    Tiezhi Sun; Yingjie Wei; Cong Wang∗

    2016-01-01

    The objective of this study is to analyze the fundamental characteristics and the thermodynamic effects of cavitating flows in liquid hydrogen. For this purpose, numerical simulation of cavitating flows are conducted over a three dimensional hydrofoil in liquid hydrogen. Firstly, the efficiency of this computational methodology is validated through comparing the simulation results with the experimental measurements of pressure and temperature. Secondly, after analysing the cavitating flows in liquid hydrogen and water, the characteristics under cryogenic conditions are highlighted. The results show that the thermodynamic effects play a significant role in the cavity structure and the mass transfer, the dimensionless mass transfer rate of liquid hydrogen is much larger, and the peak value is about ninety times as high as water at room temperature. Furthermore, a parametric study of cavitating flows on hydrofoil is conducted by considering different cavitation number and dimensionless thermodynamic coefficient. The obtained results provide an insight into the thermodynamic effect on the cavitating flows.

  10. A new method for flow measurement in cryogenic systems

    Science.gov (United States)

    Grohmann, S.

    2014-03-01

    A new method for mass flow measurement of fluids in pipes is presented; its novelty lies in the capability for intrinsic calibration. The method is founded on a concept, where two independent analytic expressions for the flow rate are formed from the same direct measurement readings (input parameters). If the input parameters were error-free, the two expressions would yield identical results, by definition. This fact can be used as goal function in a minimization routine that removes systematic errors of the inherently error-prone input parameters. The uncertainty of the mass flow measurement is then only influenced by statistical effects and is typically less than 1% with regard to the measured value. The new method is explained by a proof-of-principle that is based on measurements in a large-scale cryogenic system. The intrinsic calibrations can be executed in situ at any moment during operation of a plant, and with no need for a reference standard. While the new method is applicable in any system involving single-phase fluid flow, it offers particular advantages in cryogenic application.

  11. Phonon Sensor Dynamics for Cryogenic Dark Matter Search Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Yen, Jeffrey [Stanford Univ., CA (United States)

    2015-01-01

    Understanding the quasiparticle diffusion process inside sputtered aluminum (Al thin films (~ 0.1-1 μm is critical for the Cryogenic Dark Matter Search (CDMS experiment to further optimize its detectors to directly search for dark matter. An initial study with Al films was undertaken by our group ~ 20 years ago, but some important questions were not answered at the time. This thesis can be considered a continuation of that critical study. The CDMS experiment utilizes high purity silicon and germanium crystals to simultaneously measure ionization and phonons created by particle interactions. In addition to describing some of the rich physics involved in simultaneously detecting ionization and phonons with a CDMS detector, this thesis focuses on the detailed physics of the phonon sensors themselves, which are patterned onto CDMS detector surfaces. CDMS detectors use thin sputtered Al films to collect phonon energy when it propagates to the surfaces of the detector crystals. The phonon energy breaks Cooper pairs and creates quasiparticles (qps). These qps diffuse until they get trapped in an proximitized “overlap” region where lower-Tc tungsten films connect to the Al film. These tungsten films are the transition edge sensors (W-TESs CDMS uses to readout phonon signals. We performed a wide range of experiments using several sets of test devices designed and fabricated specifically for this work. The devices were used mostly to study quasiparticle (qp transport in Al films and qp transmission through Al/W interfaces. The results of this work are being used to optimize the design of detectors for SuperCDMS SNOLAB. This thesis is intended for CDMS collaborators who are interested in knowing more about the detailed fundamentals of how our phonon sensors work so they can take full advantage of their benefits. However, this work can also be read by general readers who are interested in particle detection using TES technology. This thesis contains eight chapters. The

  12. Constitutive model of discontinuous plastic flow at cryogenic temperatures

    CERN Document Server

    Skoczen, B; Bielski, J; Marcinek, D

    2010-01-01

    FCC metals and alloys are frequently used in cryogenic applications, nearly down to the temperature of absolute zero, because of their excellent physical and mechanical properties including ductility. Some of these materials, often characterized by the low stacking fault energy (LSFE), undergo at low temperatures three distinct phenomena: dynamic strain ageing (DSA), plastic strain induced transformation from the parent phase (gamma) to the secondary phase (alpha) and evolution of micro-damage. The constitutive model presented in the paper is focused on the discontinuous plastic flow (serrated yielding) and takes into account the relevant thermodynamic background. The discontinuous plastic flow reflecting the DSA effect is described by the mechanism of local catastrophic failure of Lomer-Cottrell (LC) locks under the stress fields related to the accumulating edge dislocations (below the transition temperature from the screw dislocations to the edge dislocations mode T-1). The failure of LC locks leads to mass...

  13. Liquid Bismuth Propellant Flow Sensor

    Science.gov (United States)

    Polzin, Kurt A.; Stanojev, B. J.; Korman, V.

    2007-01-01

    Quantifying the propellant mass flow rate in liquid bismuth-fed electric propulsion systems has two challenging facets. First, the flow sensors must be capable of providing a resolvable measurement at propellant mass flow rates on the order of 10 mg/see with and uncertainty of less that 5%. The second challenge has to do with the fact that the materials from which the flow sensors are fabricated must be capable of resisting any of the corrosive effects associated with the high-temperature propellant. The measurement itself is necessary in order to properly assess the performance (thrust efficiency, Isp) of thruster systems in the laboratory environment. The hotspot sensor[I] has been designed to provide the bismuth propellant mass flow rate measurement. In the hotspot sensor, a pulse of thermal energy (derived from a current pulse and associated joule heating) is applied near the inlet of the sensor. The flow is "tagged" with a thermal feature that is convected downstream by the flowing liquid metal. Downstream, a temperature measurement is performed to detect a "ripple" in the local temperature associated with the passing "hotspot" in the propellant. By measuring the time between the upstream generation and downstream detection of the thermal feature, the flow speed can be calculated using a "time of flight" analysis. In addition, the system can be calibrated by measuring the accumulated mass exiting the system as a-function of time and correlating this with the time it takes the hotspot to convect through the sensor. The primary advantage of this technique is that it doesn't depend on an absolute measurement of temperature but, instead, relies on the observation of thermal features. This makes the technique insensitive to other externally generated thermal fluctuations. In this paper, we describe experiments performed using the hotspot flow sensor aimed at quantifying the resolution of the sensor technology. Propellant is expelled onto an electronic scale to

  14. A Fully Transparent Flexible Sensor for Cryogenic Temperatures Based on High Strength Metallurgical Graphene.

    Science.gov (United States)

    Pawlak, Ryszard; Lebioda, Marcin; Rymaszewski, Jacek; Szymanski, Witold; Kolodziejczyk, Lukasz; Kula, Piotr

    2016-12-28

    Low-temperature electronics operating in below zero temperatures or even below the lower limit of the common -65 to 125 °C temperature range are essential in medical diagnostics, in space exploration and aviation, in processing and storage of food and mainly in scientific research, like superconducting materials engineering and their applications-superconducting magnets, superconducting energy storage, and magnetic levitation systems. Such electronic devices demand special approach to the materials used in passive elements and sensors. The main goal of this work was the implementation of a fully transparent, flexible cryogenic temperature sensor with graphene structures as sensing element. Electrodes were made of transparent ITO (Indium Tin Oxide) or ITO/Ag/ITO conductive layers by laser ablation and finally encapsulated in a polymer coating. A helium closed-cycle cryostat has been used in measurements of the electrical properties of these graphene-based temperature sensors under cryogenic conditions. The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene layers in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor).

  15. A Fully Transparent Flexible Sensor for Cryogenic Temperatures Based on High Strength Metallurgical Graphene

    Directory of Open Access Journals (Sweden)

    Ryszard Pawlak

    2016-12-01

    Full Text Available Low-temperature electronics operating in below zero temperatures or even below the lower limit of the common −65 to 125 °C temperature range are essential in medical diagnostics, in space exploration and aviation, in processing and storage of food and mainly in scientific research, like superconducting materials engineering and their applications—superconducting magnets, superconducting energy storage, and magnetic levitation systems. Such electronic devices demand special approach to the materials used in passive elements and sensors. The main goal of this work was the implementation of a fully transparent, flexible cryogenic temperature sensor with graphene structures as sensing element. Electrodes were made of transparent ITO (Indium Tin Oxide or ITO/Ag/ITO conductive layers by laser ablation and finally encapsulated in a polymer coating. A helium closed-cycle cryostat has been used in measurements of the electrical properties of these graphene-based temperature sensors under cryogenic conditions. The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene layers in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor.

  16. Numerical modeling of the flow in a cryogenic fuel tank

    Science.gov (United States)

    Greer, Donald Steven

    Developing reusable flight weight cryogenic fuel tanks is one of the technological challenges in designing advanced hypersonic aircraft and the next generation of spacecraft. As an aid in the design of these aircraft, a computational fluid dynamics (CFD) model has been developed specifically for the analysis of flow in a cryogenic fuel tank. The model simulates the transient, two dimensional draining of a fuel tank cross section. The interface between the ullage gas and liquid fuel is modeled as a free surface to enable the calculation of slosh wave dynamics. The drain rate of the liquid fuel is specified as a boundary condition to the model. The ullage gas enters the model to replace the volume of drained liquid. The rate of ullage gas entering the model is calculated from boundary conditions of constant pressure and temperature for the ullage gas. The model employs the full set of Navier-Stokes equations with the exception that viscous dissipation is neglected in the energy equation. The method of solution is an explicit finite difference technique in two dimensional generalized coordinates approximated to second order accuracy in both space and time. The stiffness due to the low Mach number is handled by the method of artificial compressibility. Model comparisons are made to experimental data for free convection to a vertical plate and to free convection inside a horizontal cylinder. Slosh wave dynamics are compared to potential flow calculations for waves inside a square tank. Sample calculations are also performed on a rectangular tank and an eight sided polygon tank to demonstrate the capability of the model.

  17. Simulation of ideal-gas flow by nitrogen and other selected gases at cryogenic temperatures. [transonic flow in cryogenic wind tunnels

    Science.gov (United States)

    Hall, R. M.; Adcock, J. B.

    1981-01-01

    The real gas behavior of nitrogen, the gas normally used in transonic cryogenic tunnels, is reported for the following flow processes: isentropic expansion, normal shocks, boundary layers, and interactions between shock waves and boundary layers. The only difference in predicted pressure ratio between nitrogen and an ideal gas which may limit the minimum operating temperature of transonic cryogenic wind tunnels occur at total pressures approaching 9 atm and total temperatures 10 K below the corresponding saturation temperature. These pressure differences approach 1 percent for both isentropic expansions and normal shocks. Alternative cryogenic test gases were also analyzed. Differences between air and an ideal diatomic gas are similar in magnitude to those for nitrogen and should present no difficulty. However, differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. It is concluded that helium and cryogenic hydrogen would not approximate the compressible flow of an ideal diatomic gas.

  18. Peltier heat flux sensor for cryogenic use; Peruchie soshi wo mochiita teion netsuryusoku sensa

    Energy Technology Data Exchange (ETDEWEB)

    Haruyama, T. [High Energy Accelerator Research Organization, Tsukuba (Japan)

    1999-06-07

    It was evaluated as cryogenic heat flux sensor, which could measure the Peltier element in In situ in thermal flux. The equipment which could proofread the thermal flux was manufactured, and on marketed several kinds general-purpose Peltier element of, the relationship between thermal flux and thermoelectromotive force at the liquid nitrogen temperature was examined. (NEDO)

  19. Limitations of Heat Conductivity in Cryogenic Sensors Due to Surface Roughness

    NARCIS (Netherlands)

    Moktadir, Z.; Bruijn, M.P.; Wiegerink, Remco J.; Elwenspoek, Michael Curt; Ridder, M.; Mels, W.A.

    2002-01-01

    The limitation of heat conductivity in cryogenic sensors due to surface roughness was discussed. It was found that at macroscopic scale and high temperatures, the transport coefficients were characteristic properties of the material and were independent of the shape and size of specimen. An

  20. The Measurement and Uncertainty Analysis of Thermal Resistance in Cryogenic Temperature Sensor Installation

    Science.gov (United States)

    Li, K. R.; Zhou, G.; Dong, B.; Liu, L. Q.; Xiong, L. Y.; Meng, R.; Li, Q.

    2017-02-01

    The choice of the appropriate installation method plays an important role for accurate temperature measurement. In the cryogenic and high vacuum environment, due to poor contact between the cryogenic temperature sensor and the surroundings that the sensor is installed and intended to measure, the self-heating from sensor measuring current brings about temperature difference and creates a potential temperature measurement error. The self-heating temperature difference is directly proportional to the thermal resistance for a mounted sensor, which means that lower installation thermal resistance of sensors is advantageous to obtain better measurement results. In this paper, a measurement model for the installation thermal resistance of sensor is built in terms of two currents method which is always used to measure self-heating effect. A cryostat that can provide variable temperature in the accurate temperature measurement and control experiments is designed and manufactured. This cryostat can reach 3K in a few hours and the sample temperature can reach as high as 20 K. Based on the experimental results, the measurement uncertainty of the thermal resistance are also analyzed and calculated. To obtain the best measurement results in our cryostat, the thermal resistances of sensors with two installation methods are measured and compared.

  1. Fiber Optic Continuous Liquid Sensor for Cryogenic Propellant Gauging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Broadband Photonics Incorporated proposes to develop a patent-pending fiber optic continuous liquid sensor for low-thrust level settled mass gauging with measurement...

  2. The performance of a piezoelectric-sensor-based SHM system under a combined cryogenic temperature and vibration environment

    Science.gov (United States)

    Qing, Xinlin P.; Beard, Shawn J.; Kumar, Amrita; Sullivan, Kevin; Aguilar, Robert; Merchant, Munir; Taniguchi, Mike

    2008-10-01

    A series of tests have been conducted to determine the survivability and functionality of a piezoelectric-sensor-based active structural health monitoring (SHM) SMART Tape system under the operating conditions of typical liquid rocket engines such as cryogenic temperature and vibration loads. The performance of different piezoelectric sensors and a low temperature adhesive under cryogenic temperature was first investigated. The active SHM system for liquid rocket engines was exposed to flight vibration and shock environments on a simulated large booster LOX-H2 engine propellant duct conditioned to cryogenic temperatures to evaluate the physical robustness of the built-in sensor network as well as operational survivability and functionality. Test results demonstrated that the developed SMART Tape system can withstand operational levels of vibration and shock energy on a representative rocket engine duct assembly, and is functional under the combined cryogenic temperature and vibration environment.

  3. Cryogenic behavior of LEDs for use in third generation LIGO position sensors and actuators

    Science.gov (United States)

    Goetz, Ryan; Tanner, David; Mueller, Guido

    2014-03-01

    The sensitivity of Advanced LIGO, the second-generation among ground-based, long-baseline interferometric gravitational-wave detectors, is expected to be limited by thermal noise of test-mass optical coatings within the frequency band of interest. To reduce the effects of thermal noise, and thereby increase the sensitivity of LIGO interferometers, the third generation of LIGO detectors will likely be operated with some optical and control components at cryogenic temperatures. In the interest of developing and investigating LIGO subsystems at low temperatures, the University of Florida LIGO Group has constructed a testbed for table-top cryogenic experiments. This presentation focuses on a preliminary investigation into cryogenic Birmingham Optical Sensors and Electro-Magnetic actuators (BOSEMS). BOSEMS are shadow sensors which are used to sense the position of and actuate on the LIGO core optics. Specifically, the low temperature I-V performance and efficiency of LEDs used in BOSEMs will be presented. Supported by NSF grant PHY-1205512.

  4. Real-Time Model-Based Leak-Through Detection within Cryogenic Flow Systems

    Science.gov (United States)

    Walker, M.; Figueroa, F.

    2015-01-01

    The timely detection of leaks within cryogenic fuel replenishment systems is of significant importance to operators on account of the safety and economic impacts associated with material loss and operational inefficiencies. Associated loss in control of pressure also effects the stability and ability to control the phase of cryogenic fluids during replenishment operations. Current research dedicated to providing Prognostics and Health Management (PHM) coverage of such cryogenic replenishment systems has focused on the detection of leaks to atmosphere involving relatively simple model-based diagnostic approaches that, while effective, are unable to isolate the fault to specific piping system components. The authors have extended this research to focus on the detection of leaks through closed valves that are intended to isolate sections of the piping system from the flow and pressurization of cryogenic fluids. The described approach employs model-based detection of leak-through conditions based on correlations of pressure changes across isolation valves and attempts to isolate the faults to specific valves. Implementation of this capability is enabled by knowledge and information embedded in the domain model of the system. The approach has been used effectively to detect such leak-through faults during cryogenic operational testing at the Cryogenic Testbed at NASA's Kennedy Space Center.

  5. Permanent downhole seismic sensors in flowing wells

    NARCIS (Netherlands)

    Jaques, P.; Ong, H.; Jupe, A.; Brown, I.; Jansenns, M.

    2003-01-01

    It is generally accepted that the 'Oilfield of the Future' will incorporate distributed permanent downhole seismic sensors in flowing wells. However the effectiveness of these sensors will be limited by the extent to which seismic signals can be discriminated, or de-coupled, from flow induced

  6. Computer program for calculating flow parameters and power requirements for cryogenic wind tunnels

    Science.gov (United States)

    Dress, D. A.

    1985-01-01

    A computer program has been written that performs the flow parameter calculations for cryogenic wind tunnels which use nitrogen as a test gas. The flow parameters calculated include static pressure, static temperature, compressibility factor, ratio of specific heats, dynamic viscosity, total and static density, velocity, dynamic pressure, mass-flow rate, and Reynolds number. Simplifying assumptions have been made so that the calculations of Reynolds number, as well as the other flow parameters can be made on relatively small desktop digital computers. The program, which also includes various power calculations, has been developed to the point where it has become a very useful tool for the users and possible future designers of fan-driven continuous-flow cryogenic wind tunnels.

  7. Scanned probe imaging of nanoscale magnetism at cryogenic temperatures with a single-spin quantum sensor.

    Science.gov (United States)

    Pelliccione, Matthew; Jenkins, Alec; Ovartchaiyapong, Preeti; Reetz, Christopher; Emmanouilidou, Eve; Ni, Ni; Bleszynski Jayich, Ania C

    2016-08-01

    High-spatial-resolution magnetic imaging has driven important developments in fields ranging from materials science to biology. However, to uncover finer details approaching the nanoscale with greater sensitivity requires the development of a radically new sensor technology. The nitrogen-vacancy (NV) defect in diamond has emerged as a promising candidate for such a sensor on the basis of its atomic size and quantum-limited sensing capabilities. It has remained an outstanding challenge to implement the NV centre as a nanoscale scanning magnetic probe at cryogenic temperatures, however, where many solid-state systems exhibit non-trivial magnetic order. Here, we present NV magnetic imaging down to 6 K with 3 μT Hz(-1/2) field sensitivity, and use the technique to image vortices in the iron pnictide superconductor BaFe2(As0.7P0.3)2 with critical temperature Tc = 30 K. The expansion of NV-based magnetic imaging to cryogenic temperatures will enable future studies of previously inaccessible nanoscale magnetism in condensed-matter systems.

  8. 169 Kelvin cryogenic microcooler employing a condenser, evaporator, flow restriction and counterflow heat exchangers

    NARCIS (Netherlands)

    Burger, Johannes Faas; Holland, Herman J.; Berenschot, Johan W.; Seppenwolde, Jan-Henry; ter Brake, Hermanus J.M.; Gardeniers, Johannes G.E.; Elwenspoek, Michael Curt

    2001-01-01

    This paper presents the first cryogenic micromachined cooler that is suitable to cool from ambient temperature to 169 kelvin and below. The cooler operates with the vapor compression cycle. It consists of a silicon micromachined condenser, a flow restriction/evaporator and two miniature glass-tube c

  9. 169 Kelvin cryogenic microcooler employing a condenser, evaporator, flow restriction and counterflow heat exchangers

    NARCIS (Netherlands)

    Burger, Johannes Faas; Holland, Herman J.; Berenschot, Johan W.; Seppenwolde, Jan-Henry; ter Brake, Hermanus J.M.; Gardeniers, Johannes G.E.; Elwenspoek, Michael Curt

    2001-01-01

    This paper presents the first cryogenic micromachined cooler that is suitable to cool from ambient temperature to 169 kelvin and below. The cooler operates with the vapor compression cycle. It consists of a silicon micromachined condenser, a flow restriction/evaporator and two miniature glass-tube

  10. Low cryogen inventory, forced flow Ne cooling system with room temperature compression stage and heat recuperation

    CERN Document Server

    Shornikov, A; Wolf, A

    2014-01-01

    We present design and commissioning results of a forced flow cooling system utilizing neon at 30 K. The cryogen is pumped through the system by a room-temperature compression stage. To decouple the cold zone from the compression stage a recuperating counterflow tube-in-tube heat exchanger is used. Commissioning demonstrated successful condensation of neon and transfer of up to 30 W cooling power to the load at 30 K using only 30 g of the cryogen circulating in the system at pressures below 170 kPa.

  11. A screen-printed flexible flow sensor

    Science.gov (United States)

    Moschos, A.; Syrovy, T.; Syrova, L.; Kaltsas, G.

    2017-04-01

    A thermal flow sensor was printed on a flexible plastic substrate using exclusively screen-printing techniques. The presented device was implemented with custom made screen-printed thermistors, which allows simple, cost-efficient production on a variety of flexible substrates while maintaining the typical advantages of thermal flow sensors. Evaluation was performed for both static (zero flow) and dynamic conditions using a combination of electrical measurements and IR imaging techniques in order to determine important characteristics, such as temperature response, output repeatability, etc. The flow sensor was characterized utilizing the hot-wire and calorimetric principles of operation, while the preliminary results appear to be very promising, since the sensor was successfully evaluated and displayed adequate sensitivity in a relatively wide flow range.

  12. Vibration Measurements to Study the Effect of Cryogen Flow in Superconducting Quadrupole.

    Energy Technology Data Exchange (ETDEWEB)

    He,P.; Anerella, M.; aydin, S.; Ganetis, G. Harrison, M.; Jain, A.; Parker, B.

    2007-06-25

    The conceptual design of compact superconducting magnets for the International Linear Collider final focus is presently under development. A primary concern in using superconducting quadrupoles is the potential for inducing additional vibrations from cryogenic operation. We have employed a Laser Doppler Vibrometer system to measure the vibrations in a spare RHIC quadrupole magnet under cryogenic conditions. Some preliminary results of these studies were limited in resolution due to a rather large motion of the laser head as well as the magnet. As a first step towards improving the measurement quality, a new set up was used that reduces the motion of the laser holder. The improved setup is described, and vibration spectra measured at cryogenic temperatures, both with and without helium flow, are presented.

  13. 2nd Biennial Conference on Refrigeration for Cryogenic Sensors and Electronic Systems

    CERN Document Server

    1983-01-01

    This proceedings documents the output of the Second Biennial Conference on Refrigeration for Cryogenic Sensors and Electronic Systems held at the National Aeronautics and Space Administration's Goddard Space Flight Center, Greenbelt, Maryland, on December 7-8, 1982. Building on the first open meeting hosted by the National Bureau of Standards in 1980, the focus of this second meeting was again on low-temperature, closed-cycle cooler technology. However, higher temperature coolers (77 K), with technology applicable to the low temperature coolers, were considered to be within the scope of this meeting. This second conference consisted of 30 papers presented by representatives of industry, government, and academia. The conference proceedings reproduced here was published by the NASA Goddard Space Flight Center in Greenbelt Maryland as NASA Conference Publication 2287.

  14. Surface-acoustic-wave (SAW) flow sensor

    Science.gov (United States)

    Joshi, Shrinivas G.

    1991-03-01

    The use of a surface-acoustic-wave (SAW) device to measure the rate of gas flow is described. A SAW oscillator heated to a suitable temperature above ambient is placed in the path of a flowing gas. Convective cooling caused by the gas flow results in a change in the oscillator frequency. A 73-MHz oscillator fabricated on 128 deg rotated Y-cut lithium niobate substrate and heated to 55 C above ambient shows a frequency variation greater than 142 kHz for flow-rate variation from 0 to 1000 cu cm/min. The output of the sensor can be calibrated to provide a measurement of volume flow rate, pressure differential across channel ports, or mass flow rate. High sensitivity, wide dynamic range, and direct digital output are among the attractive features of this sensor. Theoretical expressions for the sensitivity and response time of the sensor are derived. It is shown that by using ultrasonic Lamb waves propagating in thin membranes, a flow sensor with faster response than a SAW sensor can be realized.

  15. Morphology of Cryogenic Flows and Channels on Dwarf Planet Ceres

    Science.gov (United States)

    Krohn, Katrin; Jaumann, Ralf; Otto, Katharina A.; von der Gathen, Isabel; Matz, Klaus-Dieter; Buczkowski, Debra L.; Williams, David A.; Pieters, Carle M.; Preusker, Frank; Roatsch, Thomas; Stephan, Katrin; Wagner, Roland J.; Russell, Christopher T.; Raymond, Carol A.

    2016-04-01

    Cereś surface is affected by numerous impact craters and some of them show features such as channels or multiple flow events forming a smooth, less cratered surface, indicating possible post-impact resurfacing [1,2]. Flow features occur on several craters on Ceres such as Haulani, Ikapati, Occator, Jarimba and Kondos in combination with smooth crater floors [3,4], appearing as extended plains, ponded material, lobate flow fronts and in the case of Haulani lobate flows originating from the crest of the central ridge [3] partly overwhelming the mass wasting deposits from the rim. Haulanís crater flanks are also affected by multiple flow events radiating out from the crater and partly forming breakages. Flows occur as fine-grained lobes with well-defined margins and as smooth undifferentiated streaky flows covering the adjacent surface. Thus, adjacent craters are covered by flow material. Occator also exhibits multiple flows but in contrast to Haulani, the flows originating from the center overwhelm the mass wasting deposits from the rim [4]. The flows have a "bluish" signature in the FC color filters ratio. Channels occur at relatively fresh craters. They also show the "bluish" signature like the flows and plains. Only few channels occur at older "reddish" craters. They are relatively fresh incised into flow features or crater ejecta. Most are small, narrow and have lobated lobes with predominant distinctive flow margins. The widths vary between a few tens of meters to about 3 km. The channels are found on crater flanks as well as on the crater floors. The occurrence of flow features indicates viscous material on the surface. Those features could be formed by impact melt. However, impact melt is produced during the impact, assuming similar material properties as the ejecta it is expected to have nearly the same age as the impact itself, but the flows and plains are almost free of craters, thus, they seem to be much younger than the impact itself. In addition, the

  16. Effects of mass flow rate and droplet velocity on surface heat flux during cryogen spray cooling

    Energy Technology Data Exchange (ETDEWEB)

    Karapetian, Emil [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Aguilar, Guillermo [Department of Biomedical Engineering, University of California, Irvine, CA (United States); Kimel, Sol [Beckman Laser Institute, University of California, Irvine, CA (United States); Lavernia, Enrique J [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Nelson, J Stuart [Department of Biomedical Engineering, University of California, Irvine, CA (United States)

    2003-01-07

    Cryogen spray cooling (CSC) is used to protect the epidermis during dermatologic laser surgery. To date, the relative influence of the fundamental spray parameters on surface cooling remains incompletely understood. This study explores the effects of mass flow rate and average droplet velocity on the surface heat flux during CSC. It is shown that the effect of mass flow rate on the surface heat flux is much more important compared to that of droplet velocity. However, for fully atomized sprays with small flow rates, droplet velocity can make a substantial difference in the surface heat flux. (note)

  17. Low-drift micro flow sensors

    NARCIS (Netherlands)

    Dijkstra, Marcel

    2009-01-01

    The emerging fields of micro total-analysis systems (micro-TAS), micro-reactors and bio-MEMS drives the need for further miniaturisation of sensors measuring quantities such as pressure, temperature and flow. The research described in this thesis concerns the development of low-drift micro flow sens

  18. Novel Bio-inspired Aquatic Flow Sensors

    Science.gov (United States)

    2012-06-18

    hot - wire elements to detect changes in flow [19- 21]. Specifically, these thermal flow sensors work by using thermal anemometry , which...correlates the convective heat transfer from the hot wire to the flow rate. As a result of this property, they can also be utilized as temperature sensors...A.  E.  Perry  and  P.  A.  Libby,  " Hot -­‐ Wire   Anemometry ,"  Journal  of  Applied  Mechanics,   vol.  50,

  19. Cryogenic-temperature profiling of high-power superconducting lines using local and distributed optical-fiber sensors.

    Science.gov (United States)

    Chiuchiolo, Antonella; Palmieri, Luca; Consales, Marco; Giordano, Michele; Borriello, Anna; Bajas, Hugues; Galtarossa, Andrea; Bajko, Marta; Cusano, Andrea

    2015-10-01

    This contribution presents distributed and multipoint fiber-optic monitoring of cryogenic temperatures along a superconducting power transmission line down to 30 K and over 20 m distance. Multipoint measurements were conducted using fiber Bragg gratings sensors coated with two different functional overlays (epoxy and poly methyl methacrylate (PMMA)) demonstrating cryogenic operation in the range 300-4.2 K. Distributed measurements exploited optical frequency-domain reflectometry to analyze the Rayleigh scattering along two concatenated fibers with different coatings (acrylate and polyimide). The integrated system has been placed along the 20 m long cryostat of a superconducting power transmission line, which is currently being tested at the European Organization for Nuclear Research (CERN). Cool-down events from 300-30 K have been successfully measured in space and time, confirming the viability of these approaches to the monitoring of cryogenic temperatures along a superconducting transmission line.

  20. Cryogenic-temperature profiling of high-power superconducting lines using local and distributed optical-fiber sensors

    CERN Document Server

    Chiuchiolo, Antonella; Consales, Marco; Giordano, Michele; Borriello, Anna; Bajas, Hugues; Galtarossa, Andrea; Bajko, Marta; Cusano, Andrea

    2015-01-01

    This contribution presents distributed and multi-point fiber-optic monitoring of cryogenic temperatures along a superconducting power transmission line down to 30 K and over 20 m distance. Multi-point measurements were conducted using fiber Bragg gratings sensors coated with two different functional overlays (epoxy and PMMA) demonstrating cryogenic operation in the range 300 – 4.2 K. Distributed measurements exploited optical frequency-domain reflectometry to analyze the Rayleigh scattering along two concatenated fibers with different coatings (acrylate and polyimide). The integrated system has been placed along the 20 m long cryostat of a superconducting power transmission line, which is currently being tested at the European Organization for Nuclear Research (CERN). Cool-down events from 300 K to 30 K have been successfully measured in space and time, confirming the viability of these approaches to the monitoring of cryogenic temperatures along a superconducting transmission line.

  1. The performance of a cryogenic pump for the two-phase flow condition

    OpenAIRE

    YAMADA, HITOSHI; WATANABE, Mitsuo; Hasegawa, Satoshi; Kamijo, Kenjiro; 山田, 仁; 渡辺, 光男; 長谷川, 敏; 上條, 謙二郎

    1985-01-01

    An experimental investigation was carried out in order to obtain the performance characteristics of a cryogenic pump under a two-phase flow condition. The experiment used an oxygen pump with an inducer and liquid nitrogen as the test fluid. The vapor volumetric fraction at the pump inlet was calculated with an assumption of a constant enthalpy process across an orifice which was used to generate the two-phase flow at the pump inlet. The results showed that the pump head rise did hardly decrea...

  2. Experimental investigation on mass flow rate measurements using fibre Bragg grating sensors

    Science.gov (United States)

    Thekkethil, S. R.; Thomas, R. J.; Neumann, H.; Ramalingam, R.

    2017-02-01

    Flow measurement and control of cryogens is one of the major requirements of systems such as superconductor magnets for fusion reactors, MRI magnets etc. They can act as an early diagnostic tool for detection of any faults and ensure correct distribution of cooling load while also accessing thermal performance of the devices. Fibre Bragg Grating (FBG) sensors provide compact and accurate measurement systems which have added advantages such as immunity towards electrical and magnetic interference, low attenuation losses and remote sensing. This paper summarizes the initial experimental investigations and calibration of a novel FBG based mass flow meter. This design utilizes the viscous drag due to the flow to induce a bending strain on the fibre. The strain experienced by the fibre will be proportional to the flowrate and can be measured in terms of Bragg wavelength shift. The flowmeter is initially tested at atmospheric conditions using helium. The results are summarized and the performance parameters of the sensor are estimated. The results were also compared to a numerical model and further results for liquid helium is also reported. An overall sensitivity of 29 pm.(g.s-1)-1 was obtained for a helium flow, with a resolution of 0.2 g.s-1. A hysteresis error of 8 pm was also observed during load-unload cycles. The sensor is suitable for further tests using cryogens.

  3. Advanced flow noise reducing acoustic sensor arrays

    Science.gov (United States)

    Fine, Kevin; Drzymkowski, Mark; Cleckler, Jay

    2009-05-01

    SARA, Inc. has developed microphone arrays that are as effective at reducing flow noise as foam windscreens and sufficiently rugged for tough battlefield environments. These flow noise reducing (FNR) sensors have a metal body and are flat and conformally mounted so they can be attached to the roofs of land vehicles and are resistant to scrapes from branches. Flow noise at low Mach numbers is created by turbulent eddies moving with the fluid flow and inducing pressure variations on microphones. Our FNR sensors average the pressure over the diameter (~20 cm) of their apertures, reducing the noise created by all but the very largest eddies. This is in contrast to the acoustic wave which has negligible variation over the aperture at the frequencies of interest (f less or equal than 400 Hz). We have also post-processed the signals to further reduce the flow noise. Two microphones separated along the flow direction exhibit highly correlated noise. The time shift of the correlation corresponds to the time for the eddies in the flow to travel between the microphones. We have created linear microphone arrays parallel to the flow and have reduced flow noise as much as 10 to 15 dB by subtracting time-shifted signals.

  4. Flow field analysis of high-speed helium turboexpander for cryogenic refrigeration and liquefaction cycles

    Science.gov (United States)

    Sam, Ashish Alex; Ghosh, Parthasarathi

    2017-03-01

    Turboexpander constitutes one of the vital components of Claude cycle based helium refrigerators and liquefiers that are gaining increasing technological importance. These turboexpanders which are of radial inflow in configuration are generally high-speed micro turbines, due to the low molecular weight and density of helium. Any improvement in efficiency of these machines requires a detailed understanding of the flow field. Computational Fluid Dynamics analysis (CFD) has emerged as a necessary tool for the determination of the flow fields in cryogenic turboexpanders, which is often not possible through experiments. In the present work three-dimensional transient flow analysis of a cryogenic turboexpander for helium refrigeration and liquefaction cycles were performed using Ansys CFX®, to understand the flow field of a high-speed helium turboexpander, which in turn will help in taking appropriate decisions regarding modifications of established design methodology for improved efficiency of these machines. The turboexpander is designed based on Balje's nsds diagram and the inverse design blade profile generation formalism prescribed by Hasselgruber and Balje. The analyses include the study of several losses, their origins, the increase in entropy due to these losses, quantification of losses and the effects of various geometrical parameters on these losses. Through the flow field analysis it was observed that in the nozzle, flow separation at the nozzle blade suction side and trailing edge vortices resulted in loss generation, which calls for better nozzle blade profile. The turbine wheel flow field analysis revealed that the significant geometrical parameters of the turbine wheel blade like blade inlet angle, blade profile, tip clearance height and trailing edge thickness need to be optimised for improved performance of the turboexpander. The detailed flow field analysis in this paper can be used to improve the mean line design methodology for turboexpanders used

  5. A beam-membrane structure micromachined differential pressure flow sensor.

    Science.gov (United States)

    Chen, P; Zhao, Y L; Tian, B; Li, C; Li, Y Y

    2015-04-01

    A beam-membrane structure micromachined flow sensor is designed, depending on the principle of differential pressure caused by the mass flow, which is directly proportional to the square flow rate. The FSI (fluid structure interaction) characteristics of the differential pressure flow sensor are investigated via numerical analysis and analog simulation. The working mechanism of the flow sensor is analyzed depending on the FSI results. Then, the flow sensor is fabricated and calibrated. The calibration results show that the beam-membrane structure differential pressure flow sensor achieves ideal static characteristics and works well in the practical applications.

  6. Managing parallel cryogenic flows to the thermal intercepts in the Cornell ERL

    Science.gov (United States)

    Eichhorn, R.; Holmes, A.; Markham, S.; Sabol, D.; Smith, E.

    2014-01-01

    The proposed Cornell Energy Recovery Linac (ERL) is based on superconducting 1.3 GHz cavities operated in continuous wave mode. It presents a number of interesting cryogenic challenges, as approximately 30 cryomodules share a common vacuum space and common cryogenic distribution lines forming two 300 meter long half-linacs. Within each module, are a number of concentrated heat loads which must be intercepted at 80K and 6.5K. It is necessary to provide convective cooling by helium gas via many parallel channels to intercept these large individual loads (average up to 200W at 80K, but some as high as 400W), and we discuss the design choices made to ensure no flow instabilities. We limit the control complexity by using a single control valve for each coolant stream within each cryomodule. These streams are subdivided into parallel paths using a length of smaller diameter tubing in the cold part to limit the variation in mass flow with heat load for each path. A model describing these flows at 80 K and 5 K under different operation regimes will be derived and presented and parameters for stability will be discussed.

  7. Micro Coriolis mass flow sensor for chemical micropropulsion systems

    NARCIS (Netherlands)

    Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Groenesteijn, Jarno; Dijkstra, Pieter J.; Lötters, Joost Conrad

    2012-01-01

    We have designed a micromachined micro Coriolis flow sensor for the measurement of hydrazine (N2H4, High Purity Grade) propellant flow in micro chemical propulsion systems. The sensor measures mass flow up to 10 mg/s for a single thruster or up to 40 mg/s for four thrusters. The sensor will first be

  8. Density and Cavitating Flow Results from a Full-Scale Optical Multiphase Cryogenic Flowmeter

    Science.gov (United States)

    Korman, Valentin

    2007-01-01

    Liquid propulsion systems are hampered by poor flow measurements. The measurement of flow directly impacts safe motor operations, performance parameters as well as providing feedback from ground testing and developmental work. NASA Marshall Space Flight Center, in an effort to improve propulsion sensor technology, has developed an all optical flow meter that directly measures the density of the fluid. The full-scale sensor was tested in a transient, multiphase liquid nitrogen fluid environment. Comparison with traditional density models shows excellent agreement with fluid density with an error of approximately 0.8%. Further evaluation shows the sensor is able to detect cavitation or bubbles in the flow stream and separate out their resulting effects in fluid density.

  9. Multi-Agent Optical Sensor Chip for Cryogenic Fluids Leak Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In space missions, launch vehicles (LV) are filled with cryogenic propellant fluids. It is important to protect these LVs from any leakage of liquid propellants...

  10. Periodical shedding of cloud cavitation from a single hydrofoil in high-speed cryogenic channel flow

    Institute of Scientific and Technical Information of China (English)

    Yutaka ITO; Koichi SETO; Takao NAGASAKI

    2009-01-01

    In order to explain criteria for periodical shedding of the cloud cavitation, flow patterns of cavitation around a piano-convex hydrofoil were observed using a cryogenic cavitation tunnel of a blowdown type. Two hydrofoils of similarity of 20 and 60 mm in chord length with two test sections of 20 and 60 mm in width were prepared. Working fluids were water at ambient temperature, hot water and liquid nitrogen. The parameter range was varied between 0.3 and 1.4 for cavitation number, 9 and 17 m/sec for inlet flow velocity, and -8° and 8° for the flow in-cidence angle, respectively. At incidence angle 8°, that is, the convex surface being suction surface, periodical shedding of the whole cloud cavitation was observed on the convex surface under the specific condition with cavitation number and inlet flow velocity, respectively, 0.5, 9 m/sec for liquid nitrogen at 192℃ and 1.4, 11 m/sec for water at 88℃, whereas under the supercavitation condition, it was not observable. Periodical shedding of cloud cavitation occurs only in the case that there are both the adverse pressure gradient and the slow flow region on the hydrofoil.

  11. A 2-Dimensional Micro Flow Sensor with Wide Range Flow Sensing Properties

    Institute of Scientific and Technical Information of China (English)

    Wan-Young Chung; Tae-Yong Kim

    2006-01-01

    A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties. The micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater. A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was performed. The nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4 m/s flow and saturated from 0.75 m/s flow. However the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0 m/s. Thus, this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.

  12. Evaluation of a mass flow sensor at a gin

    Science.gov (United States)

    As part of a system to optimize the cotton ginning process, a custom-built mass flow sensor was evaluated at USDA-ARS Cotton Ginning Research Unit at Stoneville, Mississippi. The mass flow sensor was fabricated based on the principle of the sensor patented by Thomasson and Sui. The optical and ele...

  13. Sap flow sensors: construction, quality control and comparison.

    Science.gov (United States)

    Davis, Tyler W; Kuo, Chen-Min; Liang, Xu; Yu, Pao-Shan

    2012-01-01

    This work provides a design for two types of sensors, based on the thermal dissipation and heat ratio methods of sap flow calculation, for moderate to large scale deployments for the purpose of monitoring tree transpiration. These designs include a procedure for making these sensors, a quality control method for the final products, and a complete list of components with vendors and pricing information. Both sensor designs were field tested alongside a commercial sap flow sensor to assess their performance and show the importance for quality controlling the sensor outputs. Results show that for roughly 2% of the cost of commercial sensors, self-made sap flow sensors can provide acceptable estimates of the sap flow measurements compared to the commercial sensors.

  14. ASSEMBLY METHOD OF CERNOX CRYOGENIC TEMPERATURE SENSOR%CERNOX CX-SD低温温度计使用方法

    Institute of Scientific and Technical Information of China (English)

    陈飞云; 龙风; 刘方; 雷雷

    2011-01-01

    随着超导技术的飞速发展,超导装置运行过程中极低温测量技术成为一个重要的研究课题.国际上发展了许多特殊的温度测量方法,以精确测量绝对零度附近mK甚至μK量级的温度,同时对于需要具有较大温度变化范围的温度测量,例如从室温到绝对零度附近的温度测量也开发出了性能优越的温度计.在超导托卡马克核聚变实验装置的设计运行过程中,美国Lakeshore公司设计生产的CERNOX温度计得到了广泛的运用.不同型号的CERNOX温度计具有不同的特性及安装工艺,本文描述了常用的CERNOX CX-SD温度计的安装工艺以测量到准确的%With the rapid development of superconducting technology,cryogenic temperature measurement method is one of the important research field.A number of special methods of cryogenic temperature measurement have been developed to measure the temperature around absolute zero point with the mK even μK magnitude temperature precision.Special temperature sensor was developed to measure the large temperature range such as from room temperature to cryogenic temperature near absolute zero point.During the operation of superconducting TOKAMAK and other superconducting devices,CERNOX temperature sensor which is made by Lakeshore corporation has been widely used.Different temperature sensor has different characteristics and assembly techniques.In this paper,assembly method of CERNOX CX-SD temperature sensor which is recommended for its flexibility in mounting was presented.

  15. Real-gas effects 1: Simulation of ideal gas flow by cryogenic nitrogen and other selected gases

    Science.gov (United States)

    Hall, R. M.

    1980-01-01

    The thermodynamic properties of nitrogen gas do not thermodynamically approximate an ideal, diatomic gas at cryogenic temperatures. Choice of a suitable equation of state to model its behavior is discussed and the equation of Beattie and Bridgeman is selected as best meeting the needs for cryogenic wind tunnel use. The real gas behavior of nitrogen gas is compared to an ideal, diatomic gas for the following flow processes: isentropic expansion; normal shocks; boundary layers; and shock wave boundary layer interactions. The only differences in predicted pressure ratio between nitrogen and an ideal gas that may limit the minimum operating temperatures of transonic cryogenic wind tunnels seem to occur at total pressures approaching 9atmospheres and total temperatures 10 K below the corresponding saturation temperature, where the differences approach 1 percent for both isentropic expansions and normal shocks. Several alternative cryogenic test gases - air, helium, and hydrogen - are also analyzed. Differences in air from an ideal, diatomic gas are similar in magnitude to those of nitrogen. Differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. Helium and hydrogen do not approximate the compressible flow of an ideal, diatomic gas.

  16. Real-gas effects 1: Simulation of ideal gas flow by cryogenic nitrogen and other selected gases

    Science.gov (United States)

    Hall, R. M.

    1980-01-01

    The thermodynamic properties of nitrogen gas do not thermodynamically approximate an ideal, diatomic gas at cryogenic temperatures. Choice of a suitable equation of state to model its behavior is discussed and the equation of Beattie and Bridgeman is selected as best meeting the needs for cryogenic wind tunnel use. The real gas behavior of nitrogen gas is compared to an ideal, diatomic gas for the following flow processes: isentropic expansion; normal shocks; boundary layers; and shock wave boundary layer interactions. The only differences in predicted pressure ratio between nitrogen and an ideal gas that may limit the minimum operating temperatures of transonic cryogenic wind tunnels seem to occur at total pressures approaching 9atmospheres and total temperatures 10 K below the corresponding saturation temperature, where the differences approach 1 percent for both isentropic expansions and normal shocks. Several alternative cryogenic test gases - air, helium, and hydrogen - are also analyzed. Differences in air from an ideal, diatomic gas are similar in magnitude to those of nitrogen. Differences for helium and hydrogen are over an order of magnitude greater than those for nitrogen or air. Helium and hydrogen do not approximate the compressible flow of an ideal, diatomic gas.

  17. Tunable sensor response by voltage-control in biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Krijnen, G.J.M.

    2012-01-01

    We report improvements in detection limit and responsivity of biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC-bias voltage to our capacitive flow sensors mediates large (80% and more) voltage-controlled electromechanical amplification of the flow signal for freque

  18. Tunable sensor response by voltage-control in biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Krijnen, G.J.M.

    2012-01-01

    We report improvements in detection limit and responsivity of biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC-bias voltage to our capacitive flow sensors mediates large (80% and more) voltage-controlled electro-mechanical amplification of the flow signal for frequ

  19. Experimental investigation on chill-down process of cryogenic flow line

    Science.gov (United States)

    Jin, Lingxue; Park, Changgi; Cho, Hyokjin; Lee, Cheonkyu; Jeong, Sangkwon

    2016-10-01

    This paper describes the cryogenic chill-down experiments that are conducted on a 12.7 mm outer diameter, 1.25 mm wall thickness and 7 m long stainless steel horizontal pipe with liquid nitrogen (LN2). The pipe is vacuum insulated during the experiment to minimize the heat leak from room temperature and to enable one to numerically simulate the process easily. The temperature and the pressure profiles of the chill-down line are obtained at the location which is 5.5 m in a distance from the pipe inlet. The mass flux range is approximately from 19 kg/m2 s to 49 kg/m2 s, which corresponds to the Reynolds numbers range from 1469 to 5240. The transient histories of temperature, pressure and mass flow rate during the line chill-down process are monitored, and the heat transfer coefficient and the heat flux are computed by an inverse problem solving method. The amplitude of the pressure oscillation and the oscillating period become larger and longer at higher pressure conditions. In the low mass flux conditions, the critical heat flux in horizontal pipes is not sensitive to mass flux, and is higher than that in vertical pipes. Kutateladze's correlation with the constant coefficient, B = 0.029 , well matches the experimental data in the current work. In nucleate flow boiling regime, heat transfer coefficient, h , is proportional to (q″)n , and n is equal to 0.7.

  20. Evaluation of static mixer flow enhancements for cryogenic viscous compressor prototype for ITER vacuum system

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, Robert C.; Baylor, Larry R.; Meitner, Steven J.; Combs, Stephen K.; Ha, Tam; Morrow, Michael; Biewer, T. [Fusion and Materials for Nuclear System Division, Oak Ridge National Laboratory, Oak Ridge (United States); Rasmussen, David A.; Hechler, Michael P. [U.S. ITER Project Office, Oak Ridge National Laboratory, Oak Ridge (United States); Pearce, Robert J. H.; Dremel, Mattias [ITER Organization, 13115 St. Paul-lez-Durance (France); Boissin, J.-C. [Consultant, Grenoble (France)

    2014-01-29

    As part of the U.S. ITER contribution to the vacuum systems for the ITER fusion project, a cryogenic viscous compressor (CVC) is being designed and fabricated to cryopump hydrogenic gases in the torus and neutral beam exhaust streams and to regenerate the collected gases to controlled pressures such that they can be mechanically pumped with controlled flows to the tritium reprocessing facility. One critical element of the CVC design that required additional investigation was the determination of flow rates of the low pressure (up to 1000 Pa) exhaust stream that would allow for complete pumping of hydrogenic gases while permitting trace levels of helium to pass through the CVC to be pumped by conventional vacuum pumps. A sub-scale prototype test facility was utilized to determine the effectiveness of a static mixer pump tube concept, which consisted of a series of rotated twisted elements brazed into a 2-mm thick, 5-cm diameter stainless steel tube. Cold helium gas flow provided by a dewar and helium transfer line was used to cool the exterior of the static mixer pump tube. Deuterium gas was mixed with helium gas through flow controllers at different concentrations while the composition of the exhaust gas was monitored with a Penning gauge and optical spectrometer to determine the effectiveness of the static mixer. It was found that with tube wall temperatures between 6 K and 9 K, the deuterium gas was completely cryopumped and only helium passed through the tube. These results have been used to design the cooling geometry and the static mixer pump tubes in the full-scale CVC prototype.

  1. Evaluation of Static Mixer Flow Enhancements for Cryogenic Viscous Compressor Prototype for ITER Vacuum System

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, Robert C [ORNL; Baylor, Larry R [ORNL; Meitner, Steven J [ORNL; Combs, Stephen Kirk [ORNL; Ha, Tam T [ORNL; Morrow, Michael [ORNL; Biewer, Theodore M [ORNL; Rasmussen, David A [ORNL; Hechler, Michael P [ORNL; Pearce, R.J.H. [ITER Organization, Cadarache, France; Dremel, M. [ITER Organization, Cadarache, France; Boissin, Jean Claude [Consultant

    2014-01-01

    As part of the U.S. ITER contribution to the vacuum systems for the ITER fusion project, a cryogenic viscous compressor (CVC) is being designed and fabricated to cryopump hydrogenic gases in the torus and neutral beam exhaust streams and to regenerate the collected gases to controlled pressures such that they can be mechanically pumped with controlled flows to the tritium reprocessing facility. One critical element of the CVC design that required additional investigation was the determination of flow rates of the low pressure (50 to 1000 Pa) exhaust stream that would allow for complete pumping of hydrogenic gases while permitting trace levels of helium to pass through the CVC to be pumped by conventional vacuum pumps. A sub-scale prototype test facility was utilized to determine the effectiveness of a static mixer pump tube concept, which consisted of a series of rotated twisted elements brazed into a 2-mm thick, 5-cm diameter stainless steel tube. Cold helium gas flow provided by a dewar and helium transfer line was used to cool the exterior of the static mixer pump tube. Deuterium gas was mixed with helium gas through flow controllers at different concentrations while the composition of the exhaust gas was monitored with a Penning gauge and optical spectrometer to determine the effectiveness of the static mixer. It was found that with tube wall temperatures between 6 K and 9 K, the deuterium gas was completely cryopumped and only helium passed through the tube. These results have been used to design the cooling geometry and the static mixer pump tubes in the full-scale CVC prototype

  2. Cryogenic Systems

    Science.gov (United States)

    Hosoyama, Kenji

    2002-02-01

    In this lecture we discuss the principle of method of cooling to a very low temperature, i.e. cryogenic. The "gas molecular model" will be introduced to explain the mechanism cooling by the expansion engine and the Joule-Thomson expansion valve. These two expansion processes are normally used in helium refrigeration systems to cool the process gas to cryogenic temperature. The reverse Carnot cycle will be discussed in detail as an ideal refrigeration cycle. First the fundamental process of liquefaction and refrigeration cycles will be discussed, and then the practical helium refrigeration system. The process flow of the system and the key components; -compressor, expander, and heat exchanger- will be discussed. As an example of an actual refrigeration system, we will use the cryogenic system for the KEKB superconducting RF cavity. We will also discuss the liquid helium distribution system, which is very important, especially for the cryogenic systems used in accelerator applications. 1 Principles of Cooling and Fundamental Cooling Cycle 2 Expansion engine, Joule-Thomson expansion, kinetic molecular theory, and enthalpy 3 Liquefaction Systems 4 Refrigeration Systems 5 Practical helium liquefier/refrigeration system 6 Cryogenic System for TRISTAN Superconducting RF Cavity

  3. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  4. Array of Biomimetic Hair Sensor Dedicated for Flow Pattern Recognition

    NARCIS (Netherlands)

    Dagamseh, A.M.K.; Bruinink, C.M.; Kolster, Marcel; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.

    Flow sensor arrays can be used to extract features from flow fields rather than averaging or providing local measurements provided the sensors in the array structure can be interrogated individually. This paper addresses the latest developments in fabrication and array interfacing of biomimetic

  5. Hall sensor applicable to cryogenic temperatures for magnetic fields up to 25 T

    Science.gov (United States)

    Sawada, A.; Sakatsume, S.; Goto, T.; Nakamura, S.; Matsui, H.; Settai, R.; Ohtani, Y.; Watanabe, K.; Hoshi, A.

    An investigation was carried out on commercial Hall sensors used to measure the magnetic field of a superconducting magnet. Surprisingly, one of the GaAs Hall sensors, THS-119A, did not show Shubnikov-de Haas oscillations under high field conditions. This sensor, which is available as an electrical component for commercial circuits, was suitable for measuring magnetic fields up to 25 T at temperatures from 1.5 to 300 K.

  6. Focal-plane optimization for detector noise limited performance in cryogenic Fourier transform spectrometer /FTS/ sensors

    Science.gov (United States)

    Mcguirk, M.; Logan, L.

    1980-01-01

    A study was performed to determine the optimum focal plane configuration including optics, filters and detector-preamplifier selection. The configuration was optimized particularly with respect to minimizing the noise level, but fabrication considerations for a cryogenic environment were also taken into account. The noise terms from source, background, detector electronics and charged particle radiation were quantitatively evaluated. It appears that noise equivalent spectral radiance less than 10 to the -11th W/sq cm per sr per kayser can be achieved between 2.5 and 20 microns.

  7. Electrical resistance sensors record spring flow timing, Grand Canyon, Arizona

    Science.gov (United States)

    Adams, E.A.; Monroe, S.A.; Springer, A.E.; Blasch, K.W.; Bills, D.J.

    2006-01-01

    Springs along the south rim of the Grand Canyon, Arizona, are important ecological and cultural resources in Grand Canyon National Park and are discharge points for regional and local aquifers of the Coconino Plateau. This study evaluated the applicability of electrical resistance (ER) sensors for measuring diffuse, low-stage (flow in the steep, rocky spring-fed tributaries of the south rim. ER sensors were used to conduct a baseline survey of spring flow timing at eight sites in three spring-fed tributaries in Grand Canyon. Sensors were attached to a nearly vertical rock wall at a spring outlet and were installed in alluvial and bedrock channels. Spring flow timing data inferred by the ER sensors were consistent with observations during site visits, with flow events recorded with collocated streamflow gauging stations and with local precipitation gauges. ER sensors were able to distinguish the presence of flow along nearly vertical rock surfaces with flow depths between 0.3 and 1.0 cm. Laboratory experiments confirmed the ability of the sensors to monitor the timing of diffuse flow on impervious surfaces. A comparison of flow patterns along the stream reaches and at springs identified the timing and location of perennial and intermittent flow, and periods of increased evapotranspiration.

  8. Spatio-temporal flow pattern observations using bio-inspired hair flow sensors

    NARCIS (Netherlands)

    Dagamseh, Ahmad; Hmeidi, Sarah; Krijnen, Gijs

    2015-01-01

    In nature, sensing is a fundamental property of virtually all living creatures. For many insects airflow patterns, as observed by means of their hair-sensors, carry highly valuable information exposing the sources of these flows. Flow-sensor arrays can be used to extract spatio-temporal flow fields

  9. Structural integrated sensor and actuator systems for active flow control

    Science.gov (United States)

    Behr, Christian; Schwerter, Martin; Leester-Schädel, Monika; Wierach, Peter; Dietzel, Andreas; Sinapius, Michael

    2016-04-01

    An adaptive flow separation control system is designed and implemented as an essential part of a novel high-lift device for future aircraft. The system consists of MEMS pressure sensors to determine the flow conditions and adaptive lips to regulate the mass flow and the velocity of a wall near stream over the internally blown Coanda flap. By the oscillating lip the mass flow in the blowing slot changes dynamically, consequently the momentum exchange of the boundary layer over a high lift flap required mass flow can be reduced. These new compact and highly integrated systems provide a real-time monitoring and manipulation of the flow conditions. In this context the integration of pressure sensors into flow sensing airfoils of composite material is investigated. Mechanical and electrical properties of the integrated sensors are investigated under mechanical loads during tensile tests. The sensors contain a reference pressure chamber isolated to the ambient by a deformable membrane with integrated piezoresistors connected as a Wheatstone bridge, which outputs voltage signals depending on the ambient pressure. The composite material in which the sensors are embedded consists of 22 individual layers of unidirectional glass fiber reinforced plastic (GFRP) prepreg. The results of the experiments are used for adapting the design of the sensors and the layout of the laminate to ensure an optimized flux of force in highly loaded structures primarily for future aeronautical applications. It can be shown that the pressure sensor withstands the embedding process into fiber composites with full functional capability and predictable behavior under stress.

  10. Unsteady flow sensing and optimal sensor placement using machine learning

    Science.gov (United States)

    Semaan, Richard

    2016-11-01

    Machine learning is used to estimate the flow state and to determine the optimal sensor placement over a two-dimensional (2D) airfoil equipped with a Coanda actuator. The analysis is based on flow field data obtained from 2D unsteady Reynolds averaged Navier-Stokes (uRANS) simulations with different jet blowing intensities and actuation frequencies, characterizing different flow separation states. This study shows how the "random forests" algorithm is utilized beyond its typical usage in fluid mechanics estimating the flow state to determine the optimal sensor placement. The results are compared against the current de-facto standard of maximum modal amplitude location and against a brute force approach that scans all possible sensor combinations. The results show that it is possible to simultaneously infer the state of flow and to determine the optimal sensor location without the need to perform proper orthogonal decomposition. Collaborative Research Center (CRC) 880, DFG.

  11. Blade Shape Optimization of Liquid Turbine Flow Sensor

    Institute of Scientific and Technical Information of China (English)

    郭素娜; 张涛; 孙立军; 杨振; 杨文量

    2016-01-01

    Based on the characteristic curve analysis, the method using 2D(K ) square difference of meter factor at different flow rates was developed to evaluate the performance of turbine flow sensor in this study. Then according to the distribution of entrance velocity, it was supposed that reducing the blade area near the tip could decrease the linearity error of a sensor. Therefore, the influence of different blade shape parameters on the performance of the sensor was investigated by combining computational fluid dynamics(CFD)simulation with experimental test. The experimental results showed that, for the liquid turbine flow sensor with a diameter of 10 mm, the linearity error was smallest, and the performance of sensor was optimal when blade shape parameter equaled 0.25.

  12. Micromachined Sensors for Hypersonic Flows Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Interdisciplinary Consulting Corporation proposes a sensor that offers the unique capability to make wall shear stress measurement and pressure measurements for time...

  13. Micro-Machined Flow Sensors Mimicking Lateral Line Canal Neuromasts

    Directory of Open Access Journals (Sweden)

    Hendrik Herzog

    2015-08-01

    Full Text Available Fish sense water motions with their lateral line. The lateral line is a sensory system that contains up to several thousand mechanoreceptors, called neuromasts. Neuromasts occur freestanding on the skin and in subepidermal canals. We developed arrays of flow sensors based on lateral line canal neuromasts using a biomimetic approach. Each flow sensor was equipped with a PDMS (polydimethylsiloxane lamella integrated into a canal system by means of thick- and thin-film technology. Our artificial lateral line system can estimate bulk flow velocity from the spatio-temporal propagation of flow fluctuations. Based on the modular sensor design, we were able to detect flow rates in an industrial application of tap water flow metering. Our sensory system withstood water pressures of up to six bar. We used finite element modeling to study the fluid flow inside the canal system and how this flow depends on canal dimensions. In a second set of experiments, we separated the flow sensors from the main stream by means of a flexible membrane. Nevertheless, these biomimetic neuromasts were still able to sense flow fluctuations. Fluid separation is a prerequisite for flow measurements in medical and pharmaceutical applications.

  14. The Combination of Micro Diaphragm Pumps and Flow Sensors for Single Stroke Based Liquid Flow Control.

    Science.gov (United States)

    Jenke, Christoph; Pallejà Rubio, Jaume; Kibler, Sebastian; Häfner, Johannes; Richter, Martin; Kutter, Christoph

    2017-04-03

    With the combination of micropumps and flow sensors, highly accurate and secure closed-loop controlled micro dosing systems for liquids are possible. Implementing a single stroke based control mode with piezoelectrically driven micro diaphragm pumps can provide a solution for dosing of volumes down to nanoliters or variable average flow rates in the range of nL/min to μL/min. However, sensor technologies feature a yet undetermined accuracy for measuring highly pulsatile micropump flow. Two miniaturizable in-line sensor types providing electrical readout-differential pressure based flow sensors and thermal calorimetric flow sensors-are evaluated for their suitability of combining them with mircopumps. Single stroke based calibration of the sensors was carried out with a new method, comparing displacement volumes and sensor flow volumes. Limitations of accuracy and performance for single stroke based flow control are described. Results showed that besides particle robustness of sensors, controlling resistive and capacitive damping are key aspects for setting up reproducible and reliable liquid dosing systems. Depending on the required average flow or defined volume, dosing systems with an accuracy of better than 5% for the differential pressure based sensor and better than 6.5% for the thermal calorimeter were achieved.

  15. Modeling of the Response Time of Thermal Flow Sensors

    Directory of Open Access Journals (Sweden)

    Walter Lang

    2011-10-01

    Full Text Available This paper introduces a simple theoretical model for the response time of thermal flow sensors. Response time is defined here as the time needed by the sensor output signal to reach 63.2% of amplitude due to a change of fluid flow. This model uses the finite-difference method to solve the heat transfer equations, taking into consideration the transient conduction and convection between the sensor membrane and the surrounding fluid. Program results agree with experimental measurements and explain the response time dependence on the velocity and the sensor geometry. Values of the response time vary from about 5 ms in the case of stagnant flow to 1.5 ms for a flow velocity of 44 m/s.

  16. Micro coriolis mass flow sensor with integrated capacitive readout

    NARCIS (Netherlands)

    Haneveld, J.; Lammerink, T.S.J.; Boer, de M.J.; Wiegerink, R.J.

    2009-01-01

    We have realized a micromachined micro Coriolis mass flow sensor with integrated capacitive readout to detect the extremely small Coriolis vibration of the sensor tube. A special comb-like detection electrode design eliminates the need for multiple metal layers and sacrificial layer etching methods.

  17. A Blowdown Cryogenic Cavitation Tunnel and CFD Treatment for Flow Visualization around a Foil

    Institute of Scientific and Technical Information of China (English)

    Yutaka ITO; Kazuya SAWASAKI; Naoki TANI; Takao NAGASAKI; Toshio NAGASHIMA

    2005-01-01

    Cavitation is one of the major problems in the development of rocket engines. There have been few experimental studies to visualize cryogenic foil cavitation. Therefore a new cryogenic cavitation tunnel of blowdown type was built. The foil shape is "plano-convex". This profile was chosen because of simplicity, but also of being similar to the one for a rocket inducer impeller. Working fluids were water at room temperature,hot water and liquid nitrogen. In case of Angle of Attack (AOA)=8°, periodical cavity departure was observed in the experiments of both water at 90℃ and nitrogen at -190℃ under the same velocity 10 m/sec and the same cavitation number 0.7. The frequencies were observed to be 110 and 90 Hz, respectively, and almost coincided with those of vortex shedding from the foil. Temperature depression due to the thermodynamic effect was confirmed in both experiment and simulation especially in the cryogenic cavitation.

  18. Minimum detectable air velocity by thermal flow sensors.

    Science.gov (United States)

    Issa, Safir; Lang, Walter

    2013-08-19

    Miniaturized thermal flow sensors have opened the doors for a large variety of new applications due to their small size, high sensitivity and low power consumption. Theoretically, very small detection limits of air velocity of some micrometers per second are achievable. However, the superimposed free convection is the main obstacle which prevents reaching these expected limits. Furthermore, experimental investigations are an additional challenge since it is difficult to generate very low flows. In this paper, we introduce a physical method, capable of generating very low flow values in the mixed convection region. Additionally, we present the sensor characteristic curves at the zero flow case and in the mixed convection region. Results show that the estimated minimum detectable air velocity by the presented method is 0.8 mm/s. The equivalent air velocity to the noise level of the sensor at the zero flow case is about 0.13 mm/s.

  19. Systems and Sensors for Debris-flow Monitoring and Warning.

    Science.gov (United States)

    Arattano, Massimo; Marchi, Lorenzo

    2008-04-04

    Debris flows are a type of mass movement that occurs in mountain torrents. They consist of a high concentration of solid material in water that flows as a wave with a steep front. Debris flows can be considered a phenomenon intermediate between landslides and water floods. They are amongst the most hazardous natural processes in mountainous regions and may occur under different climatic conditions. Their destructiveness is due to different factors: their capability of transporting and depositing huge amounts of solid materials, which may also reach large sizes (boulders of several cubic meters are commonly transported by debris flows), their steep fronts, which may reach several meters of height and also their high velocities. The implementation of both structural and nonstructural control measures is often required when debris flows endanger routes, urban areas and other infrastructures. Sensor networks for debris-flow monitoring and warning play an important role amongst non-structural measures intended to reduce debris-flow risk. In particular, debris flow warning systems can be subdivided into two main classes: advance warning and event warning systems. These two classes employ different types of sensors. Advance warning systems are based on monitoring causative hydrometeorological processes (typically rainfall) and aim to issue a warning before a possible debris flow is triggered. Event warning systems are based on detecting debris flows when these processes are in progress. They have a much smaller lead time than advance warning ones but are also less prone to false alarms. Advance warning for debris flows employs sensors and techniques typical of meteorology and hydrology, including measuring rainfall by means of rain gauges and weather radar and monitoring water discharge in headwater streams. Event warning systems use different types of sensors, encompassing ultrasonic or radar gauges, ground vibration sensors, videocameras, avalanche pendulums, photocells

  20. Systems and Sensors for Debris-flow Monitoring and Warning

    Directory of Open Access Journals (Sweden)

    Lorenzo Marchi

    2008-04-01

    Full Text Available Debris flows are a type of mass movement that occurs in mountain torrents. They consist of a high concentration of solid material in water that flows as a wave with a steep front. Debris flows can be considered a phenomenon intermediate between landslides and water floods. They are amongst the most hazardous natural processes in mountainous regions and may occur under different climatic conditions. Their destructiveness is due to different factors: their capability of transporting and depositing huge amounts of solid materials, which may also reach large sizes (boulders of several cubic meters are commonly transported by debris flows, their steep fronts, which may reach several meters of height and also their high velocities. The implementation of both structural and nonstructural control measures is often required when debris flows endanger routes, urban areas and other infrastructures. Sensor networks for debris-flow monitoring and warning play an important role amongst non-structural measures intended to reduce debris-flow risk. In particular, debris flow warning systems can be subdivided into two main classes: advance warning and event warning systems. These two classes employ different types of sensors. Advance warning systems are based on monitoring causative hydrometeorological processes (typically rainfall and aim to issue a warning before a possible debris flow is triggered. Event warning systems are based on detecting debris flows when these processes are in progress. They have a much smaller lead time than advance warning ones but are also less prone to false alarms. Advance warning for debris flows employs sensors and techniques typical of meteorology and hydrology, including measuring rainfall by means of rain gauges and weather radar and monitoring water discharge in headwater streams. Event warning systems use different types of sensors, encompassing ultrasonic or radar gauges, ground vibration sensors, videocameras, avalanche

  1. Optimal flow sensor placement on wastewater treatment plants.

    Science.gov (United States)

    Villez, Kris; Vanrolleghem, Peter A; Corominas, Lluís

    2016-09-15

    Obtaining high quality data collected on wastewater treatment plants is gaining increasing attention in the wastewater engineering literature. Typical studies focus on recognition of faulty data with a given set of installed sensors on a wastewater treatment plant. Little attention is however given to how one can install sensors in such a way that fault detection and identification can be improved. In this work, we develop a method to obtain Pareto optimal sensor layouts in terms of cost, observability, and redundancy. Most importantly, the resulting method allows reducing the large set of possibilities to a minimal set of sensor layouts efficiently for any wastewater treatment plant on the basis of structural criteria only, with limited sensor information, and without prior data collection. In addition, the developed optimization scheme is fast. Practically important is that the number of sensors needed for both observability of all flows and redundancy of all flow sensors is only one more compared to the number of sensors needed for observability of all flows in the studied wastewater treatment plant configurations.

  2. On the use of various oscillatory air flow fields for characterization of biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Dagamseh, A.M.K.; Yntema, D.R.; Sanders, R.G.P.; Krijnen, G.J.M.

    2011-01-01

    To determine the characteristics of flow sensors, a suitable source for flow generation is required. We discuss three different sources for oscillating air flow, by considering their acoustic impedance, frequency range, velocity and ability to distinguish between flow and pressure. We discuss the im

  3. On the Use of Various Oscillatory Air Flow Fields for Characterization of Biomimetic Hair Flow Sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Dagamseh, A.M.K.; Yntema, D.R.; Sanders, R.G.P.; Krijnen, G.J.M.

    2011-01-01

    To determine the characteristics of flow sensors, a suitable source for flow generation is required. We discuss three different sources for oscillating air flow, by considering their acoustic impedance, frequency range, velocity and ability to distinguish between flow and pressure. We discuss the im

  4. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    Science.gov (United States)

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  5. Driving Perpendicular Heat Flow: (p×n)-Type Transverse Thermoelectrics for Microscale and Cryogenic Peltier Cooling

    Science.gov (United States)

    Zhou, Chuanle; Birner, S.; Tang, Yang; Heinselman, K.; Grayson, M.

    2013-05-01

    Whereas thermoelectric performance is normally limited by the figure of merit ZT, transverse thermoelectrics can achieve arbitrarily large temperature differences in a single leg even with inferior ZT by being geometrically tapered. We introduce a band-engineered transverse thermoelectric with p-type Seebeck in one direction and n-type orthogonal, resulting in off-diagonal terms that drive heat flow transverse to electrical current. Such materials are advantageous for microscale devices and cryogenic temperatures—exactly the regimes where standard longitudinal thermoelectrics fail. InAs/GaSb type II superlattices are shown to have the appropriate band structure for use as a transverse thermoelectric.

  6. Sensor chip and apparatus for tactile and/or flow sensing

    Science.gov (United States)

    Liu, Chang (Inventor); Chen, Jack (Inventor); Engel, Jonathan (Inventor)

    2009-01-01

    A sensor chip, comprising a flexible, polymer-based substrate, and at least one microfabricated sensor disposed on the substrate and including a conductive element. The at least one sensor comprises at least one of a tactile sensor and a flow sensor. Other embodiments of the present invention include sensors and/or multi-modal sensor nodes.

  7. TECHNOLOGY EVALUATION REPORT, HYDROTECHNICS IN SITU FLOW SENSOR

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program evaluated performance of HydroTechnics, Inc. flow sensors in measuring the three-dimensional flow pattern created by operation of the Wasatch Environmental, Inc. (WEI) ground...

  8. Parametric amplification in a micro Coriolis mass flow sensor

    NARCIS (Netherlands)

    Groenesteijn, J.; Droogendijk, H.; Wiegerink, R.J.; Lammerink, T.S.J.; Lötters, J.C.; Sanders, R.G.P.; Krijnen, G.J.M.

    2014-01-01

    We report on the application of parametric amplification to a micro Coriolis mass flow sensor. We demonstrate that this mechanism allows for reduction of the system's power dissipation while retaining sensitivity to flow. By reducing this power dissipation, less heat will be transferred to the fluid

  9. Fiber Optic Cryogenic Sensors for Superconducting Magnets and Superconducting Power Transmission lines at CERN

    CERN Document Server

    Chiuchiolo, A; Cusano, A; Bajko, M; Perez, J C; Bajas, H; Giordano, M; Breglio, G; Palmieri, L

    2014-01-01

    The design, fabrication and tests of a new generation of superconducting magnets for the upgrade of the LHC require the support of an adequate, robust and reliable sensing technology. The use of Fiber Optic Sensors is becoming particularly challenging for applications in extreme harsh environments such as ultra-low temperatures, high electromagnetic fields and strong mechanical stresses offering perspectives for the development of technological innovations in several applied disciplines.

  10. An electrode polarization impedance based flow sensor for low water flow measurement

    Science.gov (United States)

    Yan, Tinghu; Sabic, Darko

    2013-06-01

    This note describes an electrode polarization impedance based flow sensor for low water flow measurement. It consists of two pairs of stainless steel electrodes set apart and inserted into a non-conductive flow tube with each pair of electrodes placed diametrically at the opposite sides. The flow sensor is modeled as a typical four-electrode system of which two electrodes are current-carrying and the other two serve as output pick ups. The polarization impedances of the two current carrying electrodes are affected by water flows resulting in changes of differential potential between the two pick-up electrodes which are separated by the same fluid. The interrogation of the two excitation electrodes with dc biased ac signals offers significantly higher sensor sensitivities to flow. The prototype flow sensor constructed for a 20 mm diameter pipeline was able to measure water flow rate as low as tested at 1.06 l h-1 and remained sensitive at a flow rate of 25.18 l h-1 when it was driven with a sinusoidal voltage at 1000 Hz with a peak ac amplitude of 2 V and a dc offset of +8 V. The nonlinear characteristics of the sensor response indicate that the sensor is more sensitive at low flows and will not be able to measure at very high flows. Additional experiments are needed to evaluate the influences of impurities, chemical species, ions constituents, conductivity and temperature over a practical range of residential water conditions, the effects of fluctuating ground signals, measurement uncertainty, power consumption, compensation of effects and practical operations. The flow sensor (principle) presented may be used as (in) a secondary sensor in combination with an existing electronic water meter to extend the low end of measurement range in residential water metering.

  11. Distributed thermal micro sensors for fluid flow

    NARCIS (Netherlands)

    Baar, van John Joannes Jacobus

    2002-01-01

    In this thesis the framework of thermal sensor-actuator structures is proposed for measuring the parameters pressure p, dynamic viscosity μ, thermal conductivity , specific heat c, density and fluid velocity v. All structures are based on simple resistive elements that can be used as actuator and s

  12. Smart Sensing Strip Using Monolithically Integrated Flexible Flow Sensor for Noninvasively Monitoring Respiratory Flow.

    Science.gov (United States)

    Jiang, Peng; Zhao, Shuai; Zhu, Rong

    2015-12-15

    This paper presents a smart sensing strip for noninvasively monitoring respiratory flow in real time. The monitoring system comprises a monolithically-integrated flexible hot-film flow sensor adhered on a molded flexible silicone case, where a miniaturized conditioning circuit with a Bluetooth4.0 LE module are packaged, and a personal mobile device that wirelessly acquires respiratory data transmitted from the flow sensor, executes extraction of vital signs, and performs medical diagnosis. The system serves as a wearable device to monitor comprehensive respiratory flow while avoiding use of uncomfortable nasal cannula. The respiratory sensor is a flexible flow sensor monolithically integrating four elements of a Wheatstone bridge on single chip, including a hot-film resistor, a temperature-compensating resistor, and two balancing resistors. The monitor takes merits of small size, light weight, easy operation, and low power consumption. Experiments were conducted to verify the feasibility and effectiveness of monitoring and diagnosing respiratory diseases using the proposed system.

  13. Biomimetic flow sensors for environmental awareness

    NARCIS (Netherlands)

    Krijnen, Gijsbertus J.M.; Dagamseh, A.M.K.

    Crickets possess hairy organs attached to their abdomen, the so-called cerci. These cerci contain highly flow-sensitive mechanosensors that enable the crickets to monitor the flow-field around them and react to specific stimuli form the environment, e.g. air-movements generated by hunting spiders.

  14. Biomimetic flow sensors for environmental awareness

    NARCIS (Netherlands)

    Krijnen, Gijs J.; Dagamseh, Ahmad

    2013-01-01

    Crickets possess hairy organs attached to their abdomen, the so-called cerci. These cerci contain highly flow-sensitive mechanosensors that enable the crickets to monitor the flow-field around them and react to specific stimuli form the environment, e.g. air-movements generated by hunting spiders. S

  15. Nanoparticle embedded enzymes for improved lateral flow sensors.

    Science.gov (United States)

    Özalp, Veli C; Zeydanlı, Uğur S; Lunding, Anita; Kavruk, Murat; Öz, M Tufan; Eyidoğan, Füsun; Olsen, Lars F; Öktem, Hüseyin A

    2013-08-01

    In this study, combining the nanoparticle embedded sensors with lateral flow assays, a novel strategy for ensuring the quality of signalling in lateral flow assays (LFAs) was developed. A LFA for reactive oxygen species (ROS) is reported that is based on horse radish peroxidase (HRP) which is co-entrapped with Texas Red dextran inside porous polyacrylamide nanoparticles. In this system, enzymes are protected in the porous matrix of polyacrylamide which freely allows the diffusion of the analyte. The sensor is rapid and sensitive for quantification of hydrogen peroxide concentrations. A test solution of hydrogen peroxides was quantified with this novel LFA-ROS sensor to obtain a linear range between 1 and 25 μM. Nanoparticle embedding of enzymes is proposed here as a general strategy for developing enzyme-based lateral flow assays, eliminating adverse effects associated with biological samples.

  16. Nanoparticle embedded enzymes for improved lateral flow sensors

    DEFF Research Database (Denmark)

    Özalp, Veli Cengiz; Zeydanlı, Uğur S.; Lunding, Anita

    2013-01-01

    In this study, combining the nanoparticle embedded sensors with lateral flow assays, a novel strategy for ensuring the quality of signalling in lateral flow assays (LFAs) was developed. A LFA for reactive oxygen species (ROS) is reported that is based on horse radish peroxidase (HRP) which is co......-entrapped with Texas Red dextran inside porous polyacrylamide nanoparticles. In this system, enzymes are protected in the porous matrix of polyacrylamide which freely allows the diffusion of the analyte. The sensor is rapid and sensitive for quantification of hydrogen peroxide concentrations. A test solution...... of hydrogen peroxides was quantified with this novel LFA-ROS sensor to obtain a linear range between 1 and 25 μM. Nanoparticle embedding of enzymes is proposed here as a general strategy for developing enzyme-based lateral flow assays, eliminating adverse effects associated with biological samples....

  17. Ionization based multi-directional flow sensor

    Science.gov (United States)

    Chorpening, Benjamin T.; Casleton, Kent H.

    2009-04-28

    A method, system, and apparatus for conducting real-time monitoring of flow (airflow for example) in a system (a hybrid power generation system for example) is disclosed. The method, system and apparatus measure at least flow direction and velocity with minimal pressure drop and fast response. The apparatus comprises an ion source and a multi-directional collection device proximate the ion source. The ion source is configured to generate charged species (electrons and ions for example). The multi-directional collection source is configured to determine the direction and velocity of the flow in real-time.

  18. Contactless Impedance Sensors and Their Application to Flow Measurements

    Directory of Open Access Journals (Sweden)

    Karel Štulík

    2013-02-01

    Full Text Available The paper provides a critical discussion of the present state of the theory of high-frequency impedance sensors (now mostly called contactless impedance or conductivity sensors, the principal approaches employed in designing impedance flow-through cells and their operational parameters. In addition to characterization of traditional types of impedance sensors, the article is concerned with the use of less common sensors, such as cells with wire electrodes or planar cells. There is a detailed discussion of the effect of the individual operational parameters (width and shape of the electrodes, detection gap, frequency and amplitude of the input signal on the response of the detector. The most important problems to be resolved in coupling these devices with flow-through measurements in the liquid phase are also discussed. Examples are given of cell designs for continuous flow and flow-injection analyses and of detection systems for miniaturized liquid chromatography and capillary electrophoresis. New directions for the use of these sensors in molecular biology and chemical reactors and some directions for future development are outlined.

  19. Contactless impedance sensors and their application to flow measurements.

    Science.gov (United States)

    Opekar, František; Tůma, Petr; Stulík, Karel

    2013-02-27

    The paper provides a critical discussion of the present state of the theory of high-frequency impedance sensors (now mostly called contactless impedance or conductivity sensors), the principal approaches employed in designing impedance flow-through cells and their operational parameters. In addition to characterization of traditional types of impedance sensors, the article is concerned with the use of less common sensors, such as cells with wire electrodes or planar cells. There is a detailed discussion of the effect of the individual operational parameters (width and shape of the electrodes, detection gap, frequency and amplitude of the input signal) on the response of the detector. The most important problems to be resolved in coupling these devices with flow-through measurements in the liquid phase are also discussed. Examples are given of cell designs for continuous flow and flow-injection analyses and of detection systems for miniaturized liquid chromatography and capillary electrophoresis. New directions for the use of these sensors in molecular biology and chemical reactors and some directions for future development are outlined.

  20. Cryogenic Fiber Optic Sensors for Superconducting Magnets and Power Transmission Lines in High Energy Physics Applications

    CERN Document Server

    AUTHOR|(CDS)2081689; Bajko, Marta

    In the framework of the Luminosity upgrade of the Large Hadron Collider (HL - LHC), a remarkable R&D effort is now ongoing at the European Organization for Nuclear Research (CERN) in order to develop a new generation of accelerator magnets and superconducting power transmission lines. The magnet technology will be based on Nb3Sn enabling to operate in the 11 - 13 T range. In parallel, in order to preserve the power converters from the increasing radiation level, high power transmission lines are foreseen to feed the magnets from free - radiation zones. These will be based on high temperature superconductors cooled down with helium gas in the range 5 - 30 K. The new technologies will require advanced design and fabrication approaches as well as adapted instrumentation for monitoring both the R&D phase and operation. Resistive sensors have been used so far for voltage, temperature and strain monitoring but their integration still suffers from the number of electrical wires and the complex compensation o...

  1. Arrays of biomimetic hair flow-sensor dedicated for measuring flow patterns

    NARCIS (Netherlands)

    Dagamseh, A.M.K.; Krijnen, G.J.M.

    2011-01-01

    Next to image sensors, future’s robots will definitely use a variety of sensing mechanisms for navigation and prevention of risks to human life, for example flow-sensor arrays for 3D hydrodynamic reconstruction of the near environment. This paper aims to quantify the possibilities of our artificial

  2. Investigations of pulsed heat loads on a forced flow supercritical helium loop. Part B: Simulation of the cryogenic circuit

    Science.gov (United States)

    Vallcorba, R.; Hitz, D.; Rousset, B.; Lagier, B.; Hoa, C.

    2012-07-01

    The VINCENTA software is applied to model the transient thermal-hydraulic flow of the HELIOS supercritical helium circuit. This cryogenic circuit is equipped with dedicated heating to simulate pulsed heat loads - See Part A for the description of the experimental set up. Currently, one of the main important problems to be solved is the control and smoothing of heat pulses in the cryogenic circuit to keep the refrigerator in stable operation. In this context, the aim of the present development is to get a predictive model for the experimental management of overall heat loads absorbed by the refrigerator as well as to better understand the associated physical phenomena. This preliminary model is validated with early experiments performed with the HELIOS test facility which is dedicated to simulate representative pulsed loads related to the Japanese tokamak JT60-SA. This article presents the first comparison between model and experiments for two JT60-SA relevant scaled down pulses: (20 s/600 s-1000 W) and (60 s/1800 s-750 W).

  3. Bi-directional fast flow sensor with a large dynamic range

    NARCIS (Netherlands)

    Bree, de Hans-Elias; Jansen, Henri V.; Lammerink, Theo S.J.; Krijnen, Gijs J.M.; Elwenspoek, Miko

    1998-01-01

    In this article an extended mass-flow sensor is presented. Apart from the magnitude of the flow, as an add-on to the traditional anemometer, this sensor also measures the direction of the flow. This is of interest for the flow sensor market in general, and more in particular for the safety monitorin

  4. Flow-accelerated corrosion monitoring through advanced sensors

    Science.gov (United States)

    Kim, Jung T.; Seong, Seung H.; Lee, Cheol K.; Hur, Sub; Lee, Na Y.; Lee, Sang J.

    2005-02-01

    In order to successfully implement the extended-life operation plan of the nuclear power plant (NPP), predictive maintenance based on on-line monitoring of deteriorated components becomes highly important. Pipe wall-thinning is usually caused by Flow-Accelerated Corrosion (FAC) under the undesirable combination of water chemistry, flow velocity and material composition. In order to increase the confidence of understanding on underlying process, a multi-disciplinary approach has been adopted in this work. Here, we apply a combination of several advanced sensors, ranging from chemical electrodes to mechanical vibration sensors to monitor the thickness change of the elbow, which can be still economical option. Electrochemical Corrosion Potential (ECP) and pH are chosen as electrochemical parameters, the change of vibration mode, displacement, and etc. are chosen as mechanical parameters to monitor the wall thinning phenomena. Electrodes are developed for the on-line monitoring of pH and ECP. Vibration is considered as a promising candidate as a mechanical parameter. Various sensors are surveyed and some are chosen based on FEM analysis result, which shows the approximate vibration range according to the thickness change. Mechanical sensors need to be sensitive enough to detect small thickness change with adequate safety margin to a pipe rupture. A few sensors are suggested to detect vibration or displacement quantitatively. Fiber optic sensors are chosen for their non-contacting property, which is appropriate for the high temperature application. Accelerometer and capacitance gage are suggested for their applicability fit to the test purpose.

  5. Port and EGR Mass Flow Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

    The note documents briefly work done on what is thought to be a new method of measurement of the pulsating flow in the intake port ot and SI engine and in the EGR returen line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, Civ. Ing. Christian Jepsen...

  6. Sensors for Using Times of Flight to Measure Flow Velocities

    Science.gov (United States)

    Fralick, Gutave; Wrbanek, John D.; Hwang, Danny; Turso, James

    2006-01-01

    Thin-film sensors for measuring flow velocities in terms of times of flight are undergoing development. These sensors are very small and can be mounted flush with surfaces of airfoils, ducts, and other objects along which one might need to measure flows. Alternatively or in addition, these sensors can be mounted on small struts protruding from such surfaces for acquiring velocity measurements at various distances from the surfaces for the purpose of obtaining boundary-layer flow-velocity profiles. These sensors are related to, but not the same as, hot-wire anemometers. Each sensor includes a thin-film, electrically conductive loop, along which an electric current is made to flow to heat the loop to a temperature above that of the surrounding fluid. Instantaneous voltage fluctuations in segments of the loop are measured by means of electrical taps placed at intervals along the loop. These voltage fluctuations are caused by local fluctuations in electrical resistance that are, in turn, caused by local temperature fluctuations that are, in turn, caused by fluctuations in flow-induced cooling and, hence, in flow velocity. The differential voltage as a function of time, measured at each pair of taps, is subjected to cross-correlation processing with the corresponding quantities measured at other pairs of taps at different locations on the loop. The cross-correlations yield the times taken by elements of fluid to travel between the pairs of taps. Then the component of velocity along the line between any two pairs of taps is calculated simply as the distance between the pairs of taps divided by the travel time. Unlike in the case of hot-wire anemometers, there is no need to obtain calibration data on voltage fluctuations versus velocity fluctuations because, at least in principle, the correlation times are independent of the calibration data.

  7. Optical measurement of a micro coriolis mass flow sensor

    NARCIS (Netherlands)

    Kristiansen, L.; Mehendale, A.; Brouwer, D.M.; Zwikker, J.M.; Klein, M.E.

    2009-01-01

    Haneveld [1,2] demonstrated a micro Coriolis mass flow sensor, operating in the measurement range of 0 to 1 g/hr achieving a resolution in the order of 10 mg/hr using a laser vibrometer. Equipped with an integrated capacitive [3] readout the measurement uncertainty amounted to 2% of the full scale r

  8. Integrated pressure sensing using capacitive Coriolis mass flow sensors

    NARCIS (Netherlands)

    Alveringh, Dennis; Wiegerink, Remco J.; Lötters, Joost Conrad

    2017-01-01

    The cross-sectional shape of microchannels is, dependent on the fabrication method, never perfectly circular. Consequently, the channels deform with the pressure, which is a non-ideal effect in flow sensors, but may be used for pressure sensing. Multiple suspended channels with different lengths

  9. Micro-cantilever flow sensor for small aircraft

    KAUST Repository

    Ghommem, Mehdi

    2013-10-01

    We extend the use of cantilever beams as flow sensors for small aircraft. As such, we propose a novel method to measure the airspeed and the angle of attack at which the air travels across a small flying vehicle. We measure beam deflections and extract information about the surrounding flow. Thus, we couple a nonlinear beam model with a potential flow simulator through a fluid-structure interaction scheme. We use this numerical approach to generate calibration curves that exhibit the trend for the variations of the limit cycle oscillations amplitudes of flexural and torsional vibrations with the air speed and the angle of attack, respectively. © The Author(s) 2013.

  10. Chemiluminometric hydrogen peroxide sensor for flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Preuschoff, F. (Inst. fuer Biotechnologie, Halle Univ. (Germany)); Spohn, U. (Inst. fuer Biotechnologie, Halle Univ. (Germany)); Blankenstein, G. (Inst. fuer Enzymtechnologie am Forschungszentrum Juelich GmbH, Duesseldorf Univ., Juelich (Germany)); Mohr, K.H. (Inst. fuer Biotechnologie, Halle Univ. (Germany)); Kula, M.R. (Inst. fuer Enzymtechnologie am Forschungszentrum Juelich GmbH, Duesseldorf Univ., Juelich (Germany))

    1993-08-01

    A chemiluminometric hydrogen peroxide sensor was developed for fast flow injection analysis. Different peroxidases were covalently immobilized on affinity membranes and compared with respect to the catalytic luminol oxidation. A photomultiplier tube is connected with a fibre bundle to the flow cell. The small cell volume of 5-10 [mu]l allows sampling rates between 90 and 200/h, depending on the flow rate. The highest sensitivity and the best longterm stability can be achieved with microbial peroxidase. Hydrogen peroxide can be determined in the range between 10[sup -3] and 10[sup -8] mol/l with a precision of < 3% (n=6, [alpha] = 0.05). The operational stability of the sensor is longer than 10 weeks. (orig.)

  11. Modeling, design, fabrication and characterization of a micro Coriolis mass flow sensor

    NARCIS (Netherlands)

    Haneveld, J.; Lammerink, T.S.J.; Boer, de M.J.; Sanders, R.G.P.; Mehendale, Aditya; Lotters, J.C.; Dijkstra, M.A.; Wiegerink, R.J.

    2010-01-01

    This paper discusses the modeling, design and realization of micromachined Coriolis mass flow sensors. A lumped element model is used to analyze and predict the sensor performance. The model is used to design a sensor for a flow range of 0–1.2 g h−1 with a maximum pressure drop of 1 bar. The sensor

  12. Measurement uncertainty budget of an interferometric flow velocity sensor

    Science.gov (United States)

    Bermuske, Mike; Büttner, Lars; Czarske, Jürgen

    2017-06-01

    Flow rate measurements are a common topic for process monitoring in chemical engineering and food industry. To achieve the requested low uncertainties of 0:1% for flow rate measurements, a precise measurement of the shear layers of such flows is necessary. The Laser Doppler Velocimeter (LDV) is an established method for measuring local flow velocities. For exact estimation of the flow rate, the flow profile in the shear layer is of importance. For standard LDV the axial resolution and therefore the number of measurement points in the shear layer is defined by the length of the measurement volume. A decrease of this length is accompanied by a larger fringe distance variation along the measurement axis which results in a rise of the measurement uncertainty for the flow velocity (uncertainty relation between spatial resolution and velocity uncertainty). As a unique advantage, the laser Doppler profile sensor (LDV-PS) overcomes this problem by using two fan-like fringe systems to obtain the position of the measured particles along the measurement axis and therefore achieve a high spatial resolution while it still offers a low velocity uncertainty. With this technique, the flow rate can be estimated with one order of magnitude lower uncertainty, down to 0:05% statistical uncertainty.1 And flow profiles especially in film flows can be measured more accurately. The problem for this technique is, in contrast to laboratory setups where the system is quite stable, that for industrial applications the sensor needs a reliable and robust traceability to the SI units, meter and second. Small deviations in the calibration can, because of the highly position depending calibration function, cause large systematic errors in the measurement result. Therefore, a simple, stable and accurate tool is needed, that can easily be used in industrial surroundings to check or recalibrate the sensor. In this work, different calibration methods are presented and their influences to the

  13. Integrated cantilever-based flow sensors with tunable sensitivity for in-line monitoring of flow fluctuations in microfluidic systems

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2014-01-01

    For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different m...... pumps connected to the microfluidic system. © 2013 by the authors; licensee MDPI, Basel, Switzerland....

  14. Sensor Device for Measuring a Direction of Incident Flow and Evaluation Device Therefor

    OpenAIRE

    Wagner, Hannes; Klüßendorf, Fabian

    2012-01-01

    The invention relates to a sensor device (4) for measuring a direction of incident flow (2) with which a flowing medium flows against the sensor device (4), having a flow body (1) which is set up to have the flowing medium flow around it, the flow body (1) having a plurality of pressure-sensitive or force-sensitive sensor elements (3) which are arranged on the outer surface of the flow body (1) or are arranged in the flow body (1) and are connected to the outer surface of the flow body (1), a...

  15. Insect-Inspired Optical-Flow Navigation Sensors

    Science.gov (United States)

    Thakoor, Sarita; Morookian, John M.; Chahl, Javan; Soccol, Dean; Hines, Butler; Zornetzer, Steven

    2005-01-01

    Integrated circuits that exploit optical flow to sense motions of computer mice on or near surfaces ( optical mouse chips ) are used as navigation sensors in a class of small flying robots now undergoing development for potential use in such applications as exploration, search, and surveillance. The basic principles of these robots were described briefly in Insect-Inspired Flight Control for Small Flying Robots (NPO-30545), NASA Tech Briefs, Vol. 29, No. 1 (January 2005), page 61. To recapitulate from the cited prior article: The concept of optical flow can be defined, loosely, as the use of texture in images as a source of motion cues. The flight-control and navigation systems of these robots are inspired largely by the designs and functions of the vision systems and brains of insects, which have been demonstrated to utilize optical flow (as detected by their eyes and brains) resulting from their own motions in the environment. Optical flow has been shown to be very effective as a means of avoiding obstacles and controlling speeds and altitudes in robotic navigation. Prior systems used in experiments on navigating by means of optical flow have involved the use of panoramic optics, high-resolution image sensors, and programmable imagedata- processing computers.

  16. Cryogenic Hybrid Magnetic Bearing

    Science.gov (United States)

    Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

    1994-01-01

    Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

  17. High-temperature zirconia microthruster with an integrated flow sensor

    Science.gov (United States)

    Lekholm, Ville; Persson, Anders; Palmer, Kristoffer; Ericson, Fredric; Thornell, Greger

    2013-05-01

    This paper describes the design, fabrication and characterization of a ceramic, heated cold-gas microthruster device made with silicon tools and high temperature co-fired ceramic processing. The device contains two opposing thrusters, each with an integrated calorimetric propellant flow sensor and a heater in the stagnation chamber of the nozzle. The exhaust from a thruster was photographed using schlieren imaging to study its behavior and search for leaks. The heater elements were tested under a cyclic thermal load and to the maximum power before failure. The nozzle heater was shown to improve the efficiency of the thruster by 6.9%, from a specific impulse of 66 to 71 s, as calculated from a decrease of the flow rate through the nozzle of 13%, from 44.9 to 39.2 sccm. The sensitivity of the integrated flow sensor was measured to 0.15 mΩ sccm-1 in the region of 0-15 sccm and to 0.04 mΩ sccm-1 above 20 sccm, with a zero-flow sensitivity of 0.27 mΩ sccm-1. The choice of yttria-stabilized zirconia as a material for the devices makes them robust and capable of surviving temperatures locally exceeding 1000 °C.

  18. Computation of Space Shuttle high-pressure cryogenic turbopump ball bearing two-phase coolant flow

    Science.gov (United States)

    Chen, Yen-Sen

    1990-01-01

    A homogeneous two-phase fluid flow model, implemented in a three-dimensional Navier-Stokes solver using computational fluid dynamics methodology is described. The application of the model to the analysis of the pump-end bearing coolant flow of the high-pressure oxygen turbopump of the Space Shuttle main engine is studied. Results indicate large boiling zones and hot spots near the ball/race contact points. The extent of the phase change of the liquid oxygen coolant flow due to the frictional and viscous heat fluxes near the contact areas has been investigated for the given inlet conditions of the coolant.

  19. Convective heat flow in space cryogenics plugs - Critical and moderate He II heat flux densities

    Science.gov (United States)

    Yuan, S. W. K.; Frederking, T. H. K.

    1990-01-01

    Plug flow rates of entropy, heat and normal fluid in phase separators and in zero net mass flow systems are, to some extent, quite similar. A simplified analysis of critical conditions is presented in agreement with data trends. A critical temperature gradient arises on the basis of the He II two-fluid model at the stability limit constraining the thermohydrodynamics of the system. Thus, the question of critical thermodynamic fluctuations associated with nucleation versus the possibility of critical gradients in externally imposed parameters is answered in favor of the latter route toward turbulence. Furthermore, a similarity equation is presented which incorporates size dependent rates for moderate heat flow densities observed in experiments.

  20. Fiber Optic Mass Flow Gauge for Liquid Cryogenic Fuel Facilities Monitoring and Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal describes a fiber optic mass flow gauge that will aid in managing liquid hydrogen and oxygen fuel storage and transport. The increasing...

  1. Helium cryogenics

    CERN Document Server

    Van Sciver, Steven W

    2012-01-01

    Twenty five years have elapsed since the original publication of Helium Cryogenics. During this time, a considerable amount of research and development involving helium fluids has been carried out culminating in several large-scale projects. Furthermore, the field has matured through these efforts so that there is now a broad engineering base to assist the development of future projects. Helium Cryogenics, 2nd edition brings these advances in helium cryogenics together in an updated form. As in the original edition, the author's approach is to survey the field of cryogenics with emphasis on helium fluids. This approach is more specialized and fundamental than that contained in other cryogenics books, which treat the associated range of cryogenic fluids. As a result, the level of treatment is more advanced and assumes a certain knowledge of fundamental engineering and physics principles, including some quantum mechanics. The goal throughout the work is to bridge the gap between the physics and engineering aspe...

  2. Cryogenic exciter

    Science.gov (United States)

    Bray, James William [Niskayuna, NY; Garces, Luis Jose [Niskayuna, NY

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  3. Boundary layer separation and reattachment detection on airfoils by thermal flow sensors.

    Science.gov (United States)

    Sturm, Hannes; Dumstorff, Gerrit; Busche, Peter; Westermann, Dieter; Lang, Walter

    2012-10-24

    A sensor concept for detection of boundary layer separation (flow separation, stall) and reattachment on airfoils is introduced in this paper. Boundary layer separation and reattachment are phenomena of fluid mechanics showing characteristics of extinction and even inversion of the flow velocity on an overflowed surface. The flow sensor used in this work is able to measure the flow velocity in terms of direction and quantity at the sensor's position and expected to determine those specific flow conditions. Therefore, an array of thermal flow sensors has been integrated (flush-mounted) on an airfoil and placed in a wind tunnel for measurement. Sensor signals have been recorded at different wind speeds and angles of attack for different positions on the airfoil. The sensors used here are based on the change of temperature distribution on a membrane (calorimetric principle). Thermopiles are used as temperature sensors in this approach offering a baseline free sensor signal, which is favorable for measurements at zero flow. Measurement results show clear separation points (zero flow) and even negative flow values (back flow) for all sensor positions. In addition to standard silicon-based flow sensors, a polymer-based flexible approach has been tested showing similar results.

  4. Optical Electronic Bragg Reflection Sensor System with Hydrodynamic Flow Applications

    Science.gov (United States)

    Lyons, D. R.

    2003-01-01

    This project, as described in the following report, involved design and fabrication of fiber optic sensors for the detection and measurement of dynamic fluid density variations. These devices are created using UV (ultraviolet) ablation and generally modified transverse holographic fiber grating techniques. The resulting phase gratings created on or immediately underneath the flat portion of D-shaped optical waveguides are characterized as evanescent field sensing devices. The primary applications include the sensor portion of a real-time localized or distributed measurement system for hydrodynamic flow, fluid density measurements, and phase change phenomena. Several design modifications were implemented in an attempt to accomplish the tasks specified in our original proposal. In addition, we have established key collaborative relationships with numerous people and institutions.

  5. Performance improvement of IPMC flow sensors with a biologically-inspired cupula structure

    Science.gov (United States)

    Lei, Hong; Sharif, Montassar Aidi; Paley, Derek A.; McHenry, Matthew J.; Tan, Xiaobo

    2016-04-01

    Ionic polymer-metal composites (IPMCs) have inherent underwater sensing and actuation properties. They can be used as sensors to collect flow information. Inspired by the hair-cell mediated receptor in the lateral line system of fish, the impact of a flexible, cupula-like structure on the performance of IPMC flow sensors is experimentally explored. The fabrication method to create a silicone-capped IPMC sensor is reported. Experiments are conducted to compare the sensing performance of the IPMC flow sensor before and after the PDMS coating under the periodic flow stimulus generated by a dipole source in still water and the laminar flow stimulus generated in a flow tank. Experimental results show that the performance of IPMC flow sensors is significantly improved under the stimulus of both periodic flow and laminar flow by the proposed silicone-capping.

  6. Butterfly valve with metal seals controls flow of hydrogen from cryogenic through high temperatures

    Science.gov (United States)

    Johnson, L. D.

    1967-01-01

    Butterfly valve with metal seals operates over a temperature range of minus 423 degrees to plus 440 degrees F with hydrogen as a medium and in a radiation environment. Media flow is controlled by an internal butterfly disk which is rotated by an actuation shaft.

  7. Flow sensor using a hollow whispering gallery mode microlaser

    Science.gov (United States)

    Ward, Jonathan M.; Yang, Yong; Chormaic, Síle N.

    2016-03-01

    Flow sensing using the concept of a hot whispering gallery microlaser is presented. Silica microcapillaries or microbubbles, coated with a layer of erbium:ytterbium (Er:Yb) doped phosphate laser glass, result in a hollow, microbottle-shaped laser geometry. The Er:Yb doped glass outer layer is pumped at 980 nm via a tapered optical fiber and whispering gallery mode (WGM) lasing is recorded at 1535 nm. When gas passes through the capillary, the WGMs shift toward shorter wavelengths due to the cooling effect of the fluid flow. In this way, thermal tuning of the lasing modes over 70 GHz can be achieved. The output end of the capillary is connected to a mass flow sensor and the WGM shift rate as a function of flow rate and pump laser power is measured, with the results fitted using hot wire anemometry theory. Flow sensing can also be realized when the cavity is passively probed at 780 nm, with the estimated Q-factor of the WGMs being in excess of 105.

  8. Biomolecular Nano-Flow-Sensor to Measure Near-Surface Flow

    Directory of Open Access Journals (Sweden)

    Noji Hiroyuki

    2009-01-01

    Full Text Available Abstract We have proposed and experimentally demonstrated that the measurement of the near-surface flow at the interface between a liquid and solid using a 10 nm-sized biomolecular motor of F1-ATPase as a nano-flow-sensor. For this purpose, we developed a microfluidic test-bed chip to precisely control the liquid flow acting on the F1-ATPase. In order to visualize the rotation of F1-ATPase, several hundreds nanometer-sized particle was immobilized at the rotational axis of F1-ATPase to enhance the rotation to be detected by optical microscopy. The rotational motion of F1-ATPase, which was immobilized on an inner surface of the test-bed chip, was measured to obtain the correlation between the near-surface flow and the rotation speed of F1-ATPase. As a result, we obtained the relationship that the rotation speed of F1-ATPase was linearly decelerated with increasing flow velocity. The mechanism of the correlation between the rotation speed and the near-surface flow remains unclear, however the concept to use biomolecule as a nano-flow-sensor was proofed successfully. (See supplementary material 1 Electronic supplementary material The online version of this article (doi:10.1007/s11671-009-9479-3 contains supplementary material, which is available to authorized users. Click here for file

  9. Preliminary results of flow fluctuation measurements in the cryogenic transonic wind tunnel

    Science.gov (United States)

    Zinovyev, V. N.; Lebiga, V. A.; Pak, A. Yu.; Quest, J.

    2012-01-01

    The detailed information about flow fluctuations structure inside the test section of Pilot of European Transonic Windtunnel (PETW) obtained by means of hot-wire anemometer and fluctuation diagram (FD) method within broad and narrow frequency band is presented. Fluctuation diagrams were derived from an array of hot wire output data measured at different overheating ratio of the probe (not less than 8) at freestream Mach numbers M = 0.2, 0.4, 0.6, 0.7, and 0.8, total temperature T0 = 118 . . . 294.7 K and unit Reynolds numbers Re1 = (5.54 . . . 108.6) · 106 1/m, respectively. Time series of these output signal data were used to obtain information of statistical and correlation features, mode, and spectral composition of flow fluctuations.

  10. Preliminary evaluation of cryogenic two-phase flow imaging using electrical capacitance tomography

    Science.gov (United States)

    Xie, Huangjun; Yu, Liu; Zhou, Rui; Qiu, Limin; Zhang, Xiaobin

    2017-09-01

    The potential application of the 2-D eight-electrode electrical capacitance tomography (ECT) to the inversion imaging of the liquid nitrogen-vaporous nitrogen (LN2-VN2) flow in the tube is theoretically evaluated. The phase distribution of the computational domain is obtained using the simultaneous iterative reconstruction technique with variable iterative step size. The detailed mathematical derivations for the calculations are presented. The calculated phase distribution for the two detached LN2 column case shows the comparable results with the water-air case, regardless of the much reduced dielectric permittivity of LN2 compared with water. The inversion images of total eight different LN2-VN2 flow patterns are presented and quantitatively evaluated by calculating the relative void fraction error and the correlation coefficient. The results demonstrate that the developed reconstruction technique for ECT has the capacity to reconstruct the phase distribution of the complex LN2-VN2 flow, while the accuracy of the inversion images is significantly influenced by the size of the discrete phase. The influence of the measurement noise on the image quality is also considered in the calculations.

  11. Guides for flow sensors selection; Guias para la seleccion de sensores de flujo

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Garcia, Gustavo; Guzman Flores, Roberto; Rodriguez Martinez, Arnulfo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    In this paper a system is presented that allows the selection and calculation on instruments for flow measurement, based on practical experiences, standards an taking into consideration the process operational characteristics such as fluid type, maximum flow rate, piping diameter, etc. The system is composed of a knowledge base and a software for the selection, calculation and de adequate recommendation of flow sensing elements for the different services needed in the power plants. [Espanol] En este trabajo se presenta un sistema que permite realizar la seleccion y calculo de instrumentos para la medicion de flujo con base en experiencias practicas, normas y tomando en cuenta las caracteristicas de operacion del proceso como el tipo de fluido, flujo maximo, diametro de tuberia, etcetera. El sistema esta compuesto por una base de conocimiento y un software para la seleccion, calculo y la recomendacion adecuada de elementos sensores de flujo para los diferentes servicios que se tienen en centrales generadoras.

  12. Non-resonant parametric amplification in biomimetic hair flow sensors: Selective gain and tunable filtering

    NARCIS (Netherlands)

    Droogendijk, H.; Bruinink, C.M.; Sanders, Remco G.P.; Krijnen, Gijsbertus J.M.

    2011-01-01

    We demonstrate that the responsivity of flow sensors for harmonic flows can be improved significantly by non-resonant parametric amplification. Using electrostatic spring softening by AC-bias voltages, increased responsivity and sharp filtering are achieved in our biomimetic flow sensors. Tunable

  13. Analytical and experimental characterization of a miniature calorimetric sensor in a pulsatile flow

    NARCIS (Netherlands)

    Gelderblom, H.; Horst, van der A.; Haartsen, J.R.; Rutten, M.C.M.; Ven, van de A.A.F.; Vosse, van de F.N.

    2010-01-01

    The behaviour of a miniature calorimetric sensor, which is under consideration for catheter-based coronary-artery-flow assessment, is investigated in both steady and pulsatile tube flows. The sensor is composed of a heating element operated at constant power and two thermopiles that measure flow-ind

  14. A volumetric flow sensor for automotive injection systems

    Science.gov (United States)

    Schmid, U.; Krötz, G.; Schmitt-Landsiedel, D.

    2008-04-01

    For further optimization of the automotive power train of diesel engines, advanced combustion processes require a highly flexible injection system, provided e.g. by the common rail (CR) injection technique. In the past, the feasibility to implement injection nozzle volumetric flow sensors based on the thermo-resistive measurement principle has been demonstrated up to injection pressures of 135 MPa (1350 bar). To evaluate the transient behaviour of the system-integrated flow sensors as well as an injection amount indicator used as a reference method, hydraulic simulations on the system level are performed for a CR injection system. Experimentally determined injection timings were found to be in good agreement with calculated values, especially for the novel sensing element which is directly implemented into the hydraulic system. For the first time pressure oscillations occurring after termination of the injection pulse, predicted theoretically, could be verified directly in the nozzle. In addition, the injected amount of fuel is monitored with the highest resolution ever reported in the literature.

  15. Data set from gas sensor array under flow modulation☆

    Science.gov (United States)

    Ziyatdinov, Andrey; Fonollosa, Jordi; Fernández, Luis; Gutiérrez-Gálvez, Agustín; Marco, Santiago; Perera, Alexandre

    2015-01-01

    Recent studies in neuroscience suggest that sniffing, namely sampling odors actively, plays an important role in olfactory system, especially in certain scenarios such as novel odorant detection. While the computational advantages of high frequency sampling have not been yet elucidated, here, in order to motivate further investigation in active sampling strategies, we share the data from an artificial olfactory system made of 16 MOX gas sensors under gas flow modulation. The data were acquired on a custom set up featured by an external mechanical ventilator that emulates the biological respiration cycle. 58 samples were recorded in response to a relatively broad set of 12 gas classes, defined from different binary mixtures of acetone and ethanol in air. The acquired time series show two dominant frequency bands: the low-frequency signal corresponds to a conventional response curve of a sensor in response to a gas pulse, and the high-frequency signal has a clear principal harmonic at the respiration frequency. The data are related to the study in [1], and the data analysis results reported there should be considered as a reference point. The data presented here have been deposited to the web site of The University of California at Irvine (UCI) Machine Learning Repository (https://archive.ics.uci.edu/ml/datasets/Gas+sensor+array+under+flow+modulation). The code repository for reproducible analysis applied to the data is hosted at the GutHub web site (https://github.com/variani/pulmon). The data and code can be used upon citation of [1]. PMID:26217733

  16. Seals For Cryogenic Turbomachines

    Science.gov (United States)

    Hendricks, Robert C.; Tam, L. T.; Braun, M. J.; Vlcek, B. L.

    1988-01-01

    Analysis considers effects of seals on stability. Report presents method of calculation of flows of cryogenic fluids through shaft seals. Key to stability is local average velocity in seal. Local average velocity strongly influenced by effects of inlet and outlet and injection of fluid.

  17. Analytical and experimental characterization of a miniature calorimetric sensor in pulsatile flow

    CERN Document Server

    Gelderblom, H; Haartsen, J R; Rutten, M C M; van de Ven, A A F; van de Vosse, F N; 10.1017/S0022112010004234

    2011-01-01

    The behaviour of a miniature calorimetric sensor, which is under consideration for catheter-based coronary artery flow assessment, is investigated in both steady and pulsatile tube flow. The sensor is composed of a heating element operated at constant power, and two thermopiles that measure flow-induced temperature differences over the sensor surface. An analytical sensor model is developed, which includes axial heat conduction in the fluid and a simple representation of the solid wall, assuming a quasi-steady sensor response to the pulsatile flow. To reduce the mathematical problem, described by a two-dimensional advection-diffusion equation, a spectral method is applied. A Fourier transform is then used to solve the resulting set of ordinary differential equations and an analytical expression for the fluid temperature is found. To validate the analytical model, experiments with the sensor mounted in a tube have been performed in steady and pulsatile water flow with various amplitudes and Strouhal numbers. E...

  18. Flow-Angle and Airspeed Sensor System (FASS) Using Flush-Mounted Hot-Films Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Micron-thin surface hot-film signatures will be used to simultaneously obtain airspeed and flow direction. The flow-angle and airspeed sensor system (FASS) will...

  19. High Sensitivity Carbon Nanotubes Flow-Rate Sensors and Their Performance Improvement by Coating

    Directory of Open Access Journals (Sweden)

    Xing Yang

    2010-05-01

    Full Text Available A new type of hot-wire flow-rate sensor (HWFS with a sensing element made of a macro-sized carbon nanotube (CNT strand is presented in this study. An effective way to improve repeatability of the CNT flow-rate sensor by coating a layer of Al2O3 on the CNT surface is proposed. Experimental results show that due to the large surface-to-volume ratio and thin coated Al2O3 layer, the CNT flow-rate sensor has higher sensitivity and faster response than a conventional platinum (Pt HWFS. It is also demonstrated that the covered CNT flow-rate sensor has better repeatability than its bare counterpart due to insulation from the surrounding environment. The proposed CNT flow-rate sensor shows application potential for high-sensitivity measurement of flow rate.

  20. Micromachined lab-on-a-tube sensors for simultaneous brain temperature and cerebral blood flow measurements.

    Science.gov (United States)

    Li, Chunyan; Wu, Pei-Ming; Hartings, Jed A; Wu, Zhizhen; Cheyuo, Cletus; Wang, Ping; LeDoux, David; Shutter, Lori A; Ramaswamy, Bharat Ram; Ahn, Chong H; Narayan, Raj K

    2012-08-01

    This work describes the development of a micromachined lab-on-a-tube device for simultaneous measurement of brain temperature and regional cerebral blood flow. The device consists of two micromachined gold resistance temperature detectors with a 4-wire configuration. One is used as a temperature sensor and the other as a flow sensor. The temperature sensor operates with AC excitation current of 500 μA and updates its outputs at a rate of 5 Hz. The flow sensor employs a periodic heating and cooling technique under constant-temperature mode and updates its outputs at a rate of 0.1 Hz. The temperature sensor is also used to compensate for temperature changes during the heating period of the flow sensor to improve the accuracy of flow measurements. To prevent thermal and electronic crosstalk between the sensors, the temperature sensor is located outside the "thermal influence" region of the flow sensor and the sensors are separated into two different layers with a thin-film Copper shield. We evaluated the sensors for accuracy, crosstalk and long-term drift in human blood-stained cerebrospinal fluid. These in vitro experiments showed that simultaneous temperature and flow measurements with a single lab-on-a-tube device are accurate and reliable over the course of 5 days. It has a resolution of 0.013 °C and 0.18 ml/100 g/min; and achieves an accuracy of 0.1 °C and 5 ml/100 g/min for temperature and flow sensors respectively. The prototype device and techniques developed here establish a foundation for a multi-sensor lab-on-a-tube, enabling versatile multimodality monitoring applications.

  1. Application of Optical Flow Sensors for Dead Reckoning, Heading Reference, Obstacle Detection, and Obstacle Avoidance

    Science.gov (United States)

    2015-09-01

    OPTICAL FLOW SENSORS FOR DEAD RECKONING, HEADING REFERENCE, OBSTACLE DETECTION, AND OBSTACLE AVOIDANCE by Tarek M. Nejah September 2015... SENSORS FOR DEAD RECKONING, HEADING REFERENCE, OBSTACLE DETECTION, AND OBSTACLE AVOIDANCE 5. FUNDING NUMBERS 6. AUTHOR(S) Nejah, Tarek M. 7...avoidance using only one optical mouse sensor was presented in this thesis. Odometry, position tracking, and obstacle avoidance are important issues in

  2. Magnetohydrodynamic and Slip Effects on the Flow and Mass Transfer over a Microcantilever-Based Sensor

    Directory of Open Access Journals (Sweden)

    M. B. Akgül

    2012-01-01

    Full Text Available Hydromagnetic flow and mass transfer of a viscous incompressible fluid over a microcantilever sensor surface are studied in the presence of slip flow. In addition, chemical reaction at the sensor surface is taken into account. The governing equations for the flow are reduced to a local nonsimilarity form. Resulting equations are solved numerically for various values of flow parameters. Effects of physical quantities on the velocity and concentration profiles are discussed in detail.

  3. μ-Biomimetic flow-sensors--introducing light-guiding PDMS structures into MEMS.

    Science.gov (United States)

    Herzog, Hendrik; Klein, Adrian; Bleckmann, Horst; Holik, Peter; Schmitz, Sam; Siebke, Georg; Tätzner, Simon; Lacher, Manfred; Steltenkamp, Siegfried

    2015-04-16

    In the area of biomimetics, engineers use inspiration from natural systems to develop technical devices, such as sensors. One example is the lateral line system of fish. It is a mechanoreceptive system consisting of up to several thousand individual sensors called neuromasts, which enable fish to sense prey, predators, or conspecifics. So far, the small size and high sensitivity of the lateral line is unmatched by man-made sensor devices. Here, we describe an artificial lateral line system based on an optical detection principle. We developed artificial canal neuromasts using MEMS technology including thick film techniques. In this work, we describe the MEMS fabrication and characterize a sensor prototype. Our sensor consists of a silicon chip, a housing, and an electronic circuit. We demonstrate the functionality of our μ-biomimetic flow sensor by analyzing its response to constant water flow and flow fluctuations. Furthermore, we discuss the sensor robustness and sensitivity of our sensor and its suitability for industrial and medical applications. In sum, our sensor can be used for many tasks, e.g. for monitoring fluid flow in medical applications, for detecting leakages in tap water systems or for air and gas flow measurements. Finally, our flow sensor can even be used to improve current knowledge about the functional significance of the fish lateral line.

  4. Integrated cantilever-based flow sensors with tunable sensitivity for in-line monitoring of flow fluctuations in microfluidic systems.

    Science.gov (United States)

    Noeth, Nadine; Keller, Stephan Sylvest; Boisen, Anja

    2013-12-23

    For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different materials (SU-8 and SiN) and with different thicknesses. The integration of arrays of holes with different hole size and number of holes allows the modification of device sensitivity, theoretical detection limit and measurement range. For an average flow in the microliter range, the cantilever deflection is directly proportional to the flow rate fluctuations in the microfluidic channel. The SiN cantilevers show a detection limit below 1 nL/min and the thinnest SU-8 cantilevers a detection limit below 5 nL/min. Finally, the sensor is applied for in-line monitoring of flow fluctuations generated by external pumps connected to the microfluidic system.

  5. Integrated Cantilever-Based Flow Sensors with Tunable Sensitivity for In-Line Monitoring of Flow Fluctuations in Microfluidic Systems

    Directory of Open Access Journals (Sweden)

    Nadine Noeth

    2013-12-01

    Full Text Available For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different materials (SU-8 and SiN and with different thicknesses. The integration of arrays of holes with different hole size and number of holes allows the modification of device sensitivity, theoretical detection limit and measurement range. For an average flow in the microliter range, the cantilever deflection is directly proportional to the flow rate fluctuations in the microfluidic channel. The SiN cantilevers show a detection limit below 1 nL/min and the thinnest SU-8 cantilevers a detection limit below 5 nL/min. Finally, the sensor is applied for in-line monitoring of flow fluctuations generated by external pumps connected to the microfluidic system.

  6. Analytical and experimental characterization of a miniature calorimetric sensor in a pulsatile flow

    NARCIS (Netherlands)

    Gelderblom, Hanneke; van der Horst, A.; Haartsen, J.R.; Rutten, M.C.M.; van de Ven, A.A.F.; van de Vosse, F.N.

    2010-01-01

    The behaviour of a miniature calorimetric sensor, which is under consideration for catheter-based coronary-artery-flow assessment, is investigated in both steady and pulsatile tube flows. The sensor is composed of a heating element operated at constant power and two thermopiles that measure

  7. Evaluation of an experimental mass-flow sensor of cotton-lint at the gin

    Science.gov (United States)

    As part of a system to optimize the cotton ginning process, a custom built mass-flow sensor was evaluated at USDA-ARS Cotton Ginning Research Unit at Stoneville, Mississippi. The mass-flow sensor was fabricated based on the principle of the senor patented by Thomasson and Sui (2004). The optical a...

  8. Determination of the sensitivity behavior of an acoustic thermal flow sensor by electronic characterization

    NARCIS (Netherlands)

    Honschoten, van J.W.; Svetovoy, V.B.; Lammerink, T.S.J.; Krijnen, G.J.M.; Elwenspoek, M.C.

    2004-01-01

    The microflown is an acoustic, thermal flow sensor that measures sound particle velocity instead of sound pressure. It is a specific example of a wide range of two- and three-wire thermal flow sensors. For most applications the microflown should be calibrated, which is usually performed acoustically

  9. Non-degenerate parametric amplification and filtering in biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Bruinink, C.M.; Sanders, R.G.P.; Krijnen, G.J.M.

    2011-01-01

    We report non-degenerate parametric amplification in our biomimetic MEMS hair-based flow-sensors with improved responsivity and sharp filtering through AC-biasing. To the best of our knowledge, this is the first flow sensor with tunable filtering by non-degenerate electromechanical parametric amplif

  10. Bioinspired carbon nanotube fuzzy fiber hair sensor for air-flow detection.

    Science.gov (United States)

    Maschmann, Matthew R; Ehlert, Gregory J; Dickinson, Benjamin T; Phillips, David M; Ray, Cody W; Reich, Greg W; Baur, Jeffery W

    2014-05-28

    Artificial hair sensors consisting of a piezoresistive carbon-nanotube-coated glass fiber embedded in a microcapillary are assembled and characterized. Individual sensors resemble a hair plug that may be integrated in a wide range of host materials. The sensors demonstrate an air-flow detection threshold of less than 1 m/s with a piezoresistive sensitivity of 1.3% per m/s air-flow change.

  11. Two-Dimensional Automatic Measurement for Nozzle Flow Distribution Using Improved Ultrasonic Sensor

    OpenAIRE

    Changyuan Zhai; Chunjiang Zhao; Xiu Wang; Ning Wang; Wei Zou; Wei Li

    2015-01-01

    Spray deposition and distribution are affected by many factors, one of which is nozzle flow distribution. A two-dimensional automatic measurement system, which consisted of a conveying unit, a system control unit, an ultrasonic sensor, and a deposition collecting dish, was designed and developed. The system could precisely move an ultrasonic sensor above a pesticide deposition collecting dish to measure the nozzle flow distribution. A sensor sleeve with a PVC tube was designed for the ultras...

  12. Imaging dipole flow sources using an artificial lateral-line system made of biomimetic hair flow sensors

    NARCIS (Netherlands)

    Dagamseh, Ahmad; Wiegerink, Remco; Lammerink, Theo; Krijnen, Gijs

    2013-01-01

    In Nature, fish have the ability to localize prey, school, navigate, etc., using the lateral-line organ. Artificial hair flow sensors arranged in a linear array shape (inspired by the lateral-line system (LSS) in fish) have been applied to measure airflow patterns at the sensor positions. Here, we t

  13. Theoretical and experimental studies of a surface acoustic wave flow sensor.

    Science.gov (United States)

    Wang, Yizhong; Li, Zheng; Qin, Lifeng; Chyu, Minking K; Wang, Qing-Ming

    2012-03-01

    A novel SAW flow sensor is proposed based on pressure measurement. The relationship between the flow rate and the pressure difference along the flow path is evaluated. The results show a linear relationship between the flow rate and pressure difference, which agrees with the past research results. Strain analysis and FEM simulation show that phase delay depends linearly on the flow rate passing the SAW sensor, whereas SAW frequency decreases linearly upon the increase of flow rate. Phase delay experiment results agree with analysis and simulation, and the frequency change falls in a reasonable range around the predicted curve.

  14. A μ-biomimetic flow sensor for medical and pharmaceutical applications.

    Science.gov (United States)

    Stepniak, Simon; Bleckmann, Horst; Herzog, Hendrik; Klein, Adrian; Schulze, Elisabeth; Taetzner, Simon; Steltenkamp, Siegfried

    2015-08-01

    Flow sensing is pivotal in many medical and pharmaceutical applications. Most commercial flow sensors are either expensive, complex, or consume a lot of energy, while low cost sensors usually lack sensitivity, robustness, or long-term stability. In addition, the maintenance and sterilization of most commercial flow sensors is difficult to perform. Here, we present a new μ-biomimetic flow sensor based on the fish lateral line. It measures flow velocity and detects the transition between laminar and turbulent flow, thereby fulfilling most requirements for medical and pharmaceutical applications. Additionally, it has a modular setup featuring a screened or passive bypass configuration, enabling it not only to meter flow in medical applications but also under harsh or well-defined environmental conditions, such as found in pharmaceutical applications. The sensor is robust and can be easily cleaned. Individual parts of the sensor can even be replaced or sterilized. In sum, this sensor opens up a whole new field of applications in the area of medical and pharmaceutical related flow monitoring.

  15. Geometric scaling of artificial hair sensors for flow measurement under different conditions

    Science.gov (United States)

    Su, Weihua; Reich, Gregory W.

    2017-03-01

    Artificial hair sensors (AHSs) have been developed for prediction of the local flow speed and aerodynamic force around an airfoil and subsequent application in vibration control of the airfoil. Usually, a specific sensor design is only sensitive to the flow speeds within its operating flow measurement region. This paper aims at expanding this flow measurement concept of using AHSs to different flow speed conditions by properly sizing the parameters of the sensors, including the dimensions of the artificial hair, capillary, and carbon nanotubes (CNTs) that make up the sensor design, based on a baseline sensor design and its working flow condition. In doing so, the glass fiber hair is modeled as a cantilever beam with an elastic foundation, subject to the distributed aerodynamic drag over the length of the hair. Hair length and diameter, capillary depth, and CNT height are scaled by keeping the maximum compressive strain of the CNTs constant for different sensors under different speed conditions. Numerical studies will demonstrate the feasibility of the geometric scaling methodology by designing AHSs for aircraft with different dimensions and flight conditions, starting from the same baseline sensor. Finally, the operating bandwidth of the scaled sensors are explored.

  16. Cryogenic technology for tracking detectors

    CERN Document Server

    Granata, V; Watts, S; Borer, K; Janos, S; Pretzl, Klaus P; Dezillie, B; Li, Z; Casagrande, L; Collins, P; Grohmann, S; Heijne, Erik H M; Lourenço, C; Niinikoski, T O; Palmieri, V G; Sonderegger, P; Borchi, E; Bruzzi, Mara; Pirollo, S; Chapuy, S; Dimcovski, Zlatomir; Grigoriev, E; Bell, W; Devine, S R H; O'Shea, V; Ruggiero, G; Smith, K; Berglund, P; de Boer, Wim; Hauler, F; Heising, S; Jungermann, L; Abreu, M C; Rato-Mendes, P; Sousa, P; Cindro, V; Mikuz, M; Zavrtanik, M; Esposito, A P; Konorov, I; Paul, S; Buontempo, S; D'Ambrosio, D; Pagano, S; Eremin, V V; Verbitskaya, E

    2001-01-01

    A low-mass cryogenic cooling technique for silicon sensor modules has been developed in the framework of the RD39 Collaboration at CERN. A prototype low-mass beam tracker cryostat has been designed, constructed and tested for applications in fixed target experiments. We shall report here briefly the main features and results of the system. (2 refs).

  17. Cryogenic gaseous photomultipliers and liquid hole- multipliers: advances in THGEM-based sensors for future noble-liquid TPCs

    Science.gov (United States)

    Arazi, L.; Coimbra, A. E. C.; Erdal, E.; Israelashvili, I.; Rappaport, M. L.; Shchemelinin, S.; Vartsky, D.; dos Santos, J. M. F.; A, Breskin

    2015-11-01

    Dual-phase noble-liquid TPCs are presently the most sensitive instruments for direct dark matter detection. Scaling up existing ton-scale designs to the multi-ton regime may prove to be technologically challenging. This includes both large-area coverage with affordable high-QE UV-photon detectors, and maintaining high precision in measuring the charge and light signals of rare events with keV-scale energy depositions. We present our recent advances in two complementary approaches to these problems: large-area cryogenic gaseous photomultipliers (GPM) for UV-photon detection, and liquid-hole multipliers (LHM) that provide electroluminescence light in response to ionization electrons and primary scintillation photons, using perforated electrodes immersed within the noble liquid. Results from a 10 cm diameter GPM coupled to a dual-phase liquid- xenon TPC demonstrate the feasibility of recording - for the first time - both primary (“S1”) and secondary (“S2”) scintillation signals, over a very broad dynamic range. The detector, comprising a triple-THGEM structure with CsI on the first element, has been operating stably at 180 K with gains larger than 105; it provided high single-photon detection efficiency - in the presence of massive alpha-particle induced S2 signals; S1 scintillation signals were recorded with time resolutions of 1.2 ns (RMS). Results with the LHM operated in liquid xenon yielded large photon gains, with a pulse-height resolution of 11% (RMS) for alpha-particle induced S2 signals. The detector response was stable over several months. The response of the S2 signals to rapid changes in pressure lead to the conclusion that the underlying mechanism for S2 light is electroluminescence in xenon bubbles trapped below the immersed THGEM electrode. Both studies have the potential of paving the way towards new designs of dual- and single-phase noble-liquid TPCs that could simplify the conception of future multi-ton detectors of dark matter and other rare

  18. Monte Carlo Comparisons to a Cryogenic Dark Matter Search Detector with low Transition-Edge-Sensor Transition Temperature

    CERN Document Server

    Leman, S W; Brink, P L; Cabrera, B; Cherry, M; Silva, E Do Couto E; Figueroa-Feliciano, E; Kim, P; Mirabolfathi, N; Pyle, M; Resch, R; Sadoulet, B; Serfass, B; Sundqvist, K M; Tomada, A; Young, B A

    2011-01-01

    We present results on phonon quasidiffusion and Transition Edge Sensor (TES) studies in a large, 3 inch diameter, 1 inch thick [100] high purity germanium crystal, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare calibration data with results from a Monte Carlo which includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels. The phonon energy is then parsed into TES based phonon readout channels and input into a TES simulator.

  19. Thin-Film Air-Mass-Flow Sensor of Improved Design Developed

    Science.gov (United States)

    Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.

    2003-01-01

    Researchers at the NASA Glenn Research Center have developed a new air-mass-flow sensor to solve the problems of existing mass flow sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other air-mass-flow sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film air-mass-flow sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-flow rate. The following figure shows a schematic of this sensor with air flowing around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no flow, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is flow, the air passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the air has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated air raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of air passing by the sensor. A current application for air-mass-flow sensors is as part of the intake system for an internal combustion engine. A mass-flow sensor is

  20. Systematic study of packaging designs on the performance of CMOS thermoresistive micro calorimetric flow sensors

    Science.gov (United States)

    Xu, Wei; Pan, Liang; Gao, Bo; Chiu, Yi; Xu, Kun; Lee, Yi-Kuen

    2017-08-01

    We systematically study the effect of two packaging configurations for the CMOS thermoresistive micro calorimetric flow (TMCF) sensors: S-type with the sensor chip protrusion-mounted on the flow channel wall and E-type with the sensor chip flush-mounted on the flow channel wall. Although the experimental results indicated that the sensitivity of the S-type was increased by more than 30%; the corresponding flow range as compared to the E-type was dramatically reduced by 60% from 0-11 m s-1 to 0-4.5 m s-1. Comprehensive 2D CFD simulation and in-house developed 3D numerical simulations based on the gas-kinetic scheme were applied to study the flow separation of these two packaging designs with the major parameters. Indeed, the S-type design with the large protrusion would change the local convective heat transfer of the TMCF sensor and dramatically decrease the sensors’ performance. In addition, parametric CFD simulations of the packaging designs provide inspiration to propose a novel general flow regime map (FRM), i.e. normalized protrusion d * versus reduced chip Reynolds number Re*, where the critical boundary curve for the flow separation of TMCF sensors was determined at different channel aspect ratios. The proposed FRM can be a useful guideline for the packaging design and manufacturing of different micro thermal flow sensors.

  1. Local Measurement of Gas-Liquid Bubbly Flow with a Double-Sensor Probe

    Institute of Scientific and Technical Information of China (English)

    孙科霞; 张鸣远; 陈学俊

    2000-01-01

    A double-sensor probe was used to measure local interfacial parameters of a gas-liquid bubbly flow in a horizontal tube. The parameters included void fraction, interfacial concentration, bubble size distribution, bubble frequency and bubble interface velocity. The authors paid special attention to the probe design and construction for minimizing measurement errors. Measures were also taken in the design of sensor ends for preventing corrosions in the flow. This is an effort to improve the current double-sensor probe technique to meet the ever-increasing needs to local varameter measurements in gas-liquid two-phase flows.

  2. Parametric amplification and stochastic resonance in bio-inspired hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Krijnen, G.J.M.

    2010-01-01

    Inspired by crickets and its perception for flow phenomena, artificial hair flow sensors have been developed successfully in our group. The realization of array structures and improvement of fabrication methodologies have led to better performance, making it possible to detect and measure flow veloc

  3. A study on performance improvement of MEMS hair flow sensors by parametric amplification

    NARCIS (Netherlands)

    Droogendijk, H.; Krijnen, G.J.M.

    2010-01-01

    Inspired by crickets and its perception for flow phenomena, artificial hair flow sensors have been developed successfully in our group. Improvement of fabrication methodologies have led to better performance, making it possible to detect and measure flow velocities in the range of sub-mm/s. To impro

  4. Cryogenic systems advanced monitoring, fault diagnostics, and predictive maintenance

    CERN Document Server

    Arpaia, Pasquale

    2017-01-01

    Cryogenics, the study and technology of materials and systems at very low temperature, is widely used for sensors and instruments requiring very highly precise measurements with low electrical resistance, especially for measurements of materials and energies at a very small scale. Thus, the need to understand how instruments operate and perform over time at temperatures below -2920 F (-1800 C) is critical, for applications from Magnetic Resonance Imaging (MRI) to Nuclear Magnetic Resonance Spectroscopy to instrumentation for particle accelerators of all kinds. This book brings to the reader guidance learned from work at the European Laboratory for Nuclear Research (CERN), and its large scale particle accelerator in Switzerland to help engineers and technicians implement best practices in instrumentation at cryogenic temperatures, including a better understanding of fault detection and predictive maintenance. Special problems with devices like flow meters, pressure gauges, and temperature gauges when operating...

  5. Flow-Angle and Airspeed Sensor System (FASS) Using Flush-Mounted Hot-Films Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Micron-thin surface hot-film gages are used to develop flow-angle and airspeed sensor system (FASS). Unlike Pitot-static and other pressure-based devices, which...

  6. Fully Integrated Micro Coriolis Mass Flow Sensor Operating at Atmospheric Pressure

    NARCIS (Netherlands)

    Wiegerink, R.J.; Lammerink, T.S.J.; Haneveld, J.; Hageman, T.A.G.; Lötters, J.C.

    2011-01-01

    This paper discusses the design and realization of a micromachined micro Coriolis flow sensor with integrated electrodes for both electrostatic actuation and capacitive readout. The sensor was realized using semicircular channels just beneath the surface of the silicon wafer. The channels have thin

  7. Fully integrated micro coriolis mass flow sensor operating at atmospheric pressure

    NARCIS (Netherlands)

    Lötters, Joost C.; Lammerink, Theo S.; Haneveld, Jeroen; Hageman, Tijmen A.G.; Wiegerink, Remco J.

    2012-01-01

    This paper discusses the design and realization of a micromachined micro Coriolis flow sensor with integrated electrodes for both electrostatic actuation and capacitive readout. The sensor was realized using semicircular channels just beneath the surface of the silicon wafer. The channels have thin

  8. Development of fiber optic sensor for fluid flow of astronauts’ life-support system

    Science.gov (United States)

    Shachneva, E. A.; Murashkina, T. I.

    2016-08-01

    This paper proposes a fiber optic sensor consumption (volume, speed) of liquids in life-support systems of astronauts, as well as offers a simple method and apparatus for reproducing the parameters of fluid flow needed in research, yustiovke and adjusting the optical sensor system.

  9. Interfacing of differential-capacitive biomimetic hair flow-sensors for optimal sensitivity

    NARCIS (Netherlands)

    Dagamseh, A.M.K.; Bruinink, C.M.; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Droogendijk, H.; Krijnen, Gijsbertus J.M.

    Biologically inspired sensor-designs are investigated as a possible path to surpass the performance of more traditionally engineered designs. Inspired by crickets, artificial hair sensors have shown the ability to detect minute flow signals. This paper addresses developments in the design,

  10. Magnetic bearings for cryogenic turbomachines

    Science.gov (United States)

    Iannello, Victor; Sixsmith, Herbert

    1991-01-01

    Magnetic bearings offer a number of advantages over gas bearings for the support of rotors in cryogenic turboexpanders and compressors. Their performance is relatively independent of the temperature or pressure of the process gas for a large range of conditions. Active magnetic bearing systems that use capacitive sensors have been developed for high speed compressors for use in cryogenic refrigerators. Here, the development of a magnetic bearing system for a miniature ultra high speed compressor is discussed. The magnetic bearing has demonstrated stability at rotational speeds exceeding 250,000 rpm. This paper describes the important features of the magnetic bearing and presents test results demonstrating its performance characteristics.

  11. CRYOGENIC MAGNETS

    Science.gov (United States)

    Post, R.F.; Taylor, C.E.

    1963-05-21

    A cryogenic magnet coil is described for generating magnetic fields of the order of 100,000 gauss with a minimum expenditure of energy lost in resistive heating of the coil inductors and energy lost irreversibly in running the coil refrigeration plant. The cryogenic coil comprises a coil conductor for generating a magnetic field upon energization with electrical current, and refrigeration means disposed in heat conductive relation to the coil conductor for cooling to a low temperature. A substantial reduction in the power requirements for generating these magnetic fields is attained by scaling the field generating coil to large size and particular dimensions for a particular conductor, and operating the coil at a particular optimum temperature commensurate with minimum overall power requirements. (AEC)

  12. Cryogenics; Criogenia

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez R, C.; Jimenez D, J.; Cejudo A, J.; Hernandez M, V. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Cryogenics is one of these technologies which contributes to scientific research that supports to the industry in the following benefits: 1. Storage ability and a great quantity of dense gases with cryogenic liquid which is found at high pressure. 2. Production ability at low cost with high purity gases through distillation or condensation. 3. Ability to use low temperatures in the refrigerating materials or alteration of the physical properties. This technology is used for reprocessing of those short and long half life radioactive wastes which always have been required that to be separated with classical methods. In this text we report the radioactive wastes separation by more sophisticated methods but more quickly and reliable. (Author)

  13. Theoretical and Experimental Study on Wide Range Optical Fiber Turbine Flow Sensor.

    Science.gov (United States)

    Du, Yuhuan; Guo, Yingqing

    2016-07-15

    In this paper, a novel fiber turbine flow sensor was proposed and demonstrated for liquid measurement with optical fiber, using light intensity modulation to measure the turbine rotational speed for converting to flow rate. The double-circle-coaxial (DCC) fiber probe was introduced in frequency measurement for the first time. Through the divided ratio of two rings light intensity, the interference in light signals acquisition can be eliminated. To predict the characteristics between the output frequency and flow in the nonlinear range, the turbine flow sensor model was built. Via analyzing the characteristics of turbine flow sensor, piecewise linear equations were achieved in expanding the flow measurement range. Furthermore, the experimental verification was tested. The results showed that the flow range ratio of DN20 turbine flow sensor was improved 2.9 times after using piecewise linear in the nonlinear range. Therefore, combining the DCC fiber sensor and piecewise linear method, it can be developed into a strong anti-electromagnetic interference(anti-EMI) and wide range fiber turbine flowmeter.

  14. Flow Webs: Mechanism and Architecture for the Implementation of Sensor Webs

    Science.gov (United States)

    Gorlick, M. M.; Peng, G. S.; Gasster, S. D.; McAtee, M. D.

    2006-12-01

    The sensor web is a distributed, federated infrastructure much like its predecessors, the internet and the world wide web. It will be a federation of many sensor webs, large and small, under many distinct spans of control, that loosely cooperates and share information for many purposes. Realistically, it will grow piecemeal as distinct, individual systems are developed and deployed, some expressly built for a sensor web while many others were created for other purposes. Therefore, the architecture of the sensor web is of fundamental import and architectural strictures that inhibit innovation, experimentation, sharing or scaling may prove fatal. Drawing upon the architectural lessons of the world wide web, we offer a novel system architecture, the flow web, that elevates flows, sequences of messages over a domain of interest and constrained in both time and space, to a position of primacy as a dynamic, real-time, medium of information exchange for computational services. The flow web captures; in a single, uniform architectural style; the conflicting demands of the sensor web including dynamic adaptations to changing conditions, ease of experimentation, rapid recovery from the failures of sensors and models, automated command and control, incremental development and deployment, and integration at multiple levels—in many cases, at different times. Our conception of sensor webs—dynamic amalgamations of sensor webs each constructed within a flow web infrastructure—holds substantial promise for earth science missions in general, and of weather, air quality, and disaster management in particular. Flow webs, are by philosophy, design and implementation a dynamic infrastructure that permits massive adaptation in real-time. Flows may be attached to and detached from services at will, even while information is in transit through the flow. This concept, flow mobility, permits dynamic integration of earth science products and modeling resources in response to real

  15. An Intelligent Traffic Flow Control System Based on Radio Frequency Identification and Wireless Sensor Networks

    OpenAIRE

    Chao, Kuei-Hsiang; Chen, Pi-Yun

    2014-01-01

    This study primarily focuses on the use of radio frequency identification (RFID) as a form of traffic flow detection, which transmits collected information related to traffic flow directly to a control system through an RS232 interface. At the same time, the sensor analyzes and judges the information using an extension algorithm designed to achieve the objective of controlling the flow of traffic. In addition, the traffic flow situation is also transmitted to a remote monitoring control syste...

  16. Development and testing of a novel single-wire sensor for wide range flow velocity measurements

    Science.gov (United States)

    Al-Salaymeh, A.; Durst, F.

    2004-05-01

    Thermal flow sensors with a wide dynamic range, e.g. 1:1000 and more, are currently not available in spite of the great demand for such sensors in practical fluid flow measurements. The present paper introduces a sensor of this kind. The new sensor is mechanically the same as the 'sending' wire of the two-wire thermal flow sensor described by Durst et al, but it is excited by discrete, widely separated, square waves of electrical current rather than a continuous sinusoidal current. The nominal 'output' of the new sensor is the increase in wire temperature so that an integral of the resistance over the pulse length can be used for measurements. This 'output' is a function of the time constant ('thermal inertia') of the heated wire and thus also of the velocity of flow. The time constant decreases as the flow velocity increases, while the heat transfer increases. At very low flow velocities the response is determined almost entirely by the time constant of the wire while at high velocities the device acts almost like a 'constant current' hot-wire anemometer. That is, the effect of thermal inertia augments the output signal of the basic hot wire, thus increasing the flow rate range/sensitivity of the device, especially at the low-velocity end, above than that of a simple hot-wire flowmeter. The sensor described here was developed for slowly changing unidirectional flows, and uses one wire of 12.5 µm diameter. It is excited at 30 Hz frequency and its usable flow velocity range is 0.01-25 m s-1.

  17. Optical flows method for lightweight agile remote sensor design and instrumentation

    Science.gov (United States)

    Wang, Chong; Xing, Fei; Wang, Hongjian; You, Zheng

    2013-08-01

    Lightweight agile remote sensors have become one type of the most important payloads and were widely utilized in space reconnaissance and resource survey. These imaging sensors are designed to obtain the high spatial, temporary and spectral resolution imageries. Key techniques in instrumentation include flexible maneuvering, advanced imaging control algorithms and integrative measuring techniques, which are closely correlative or even acting as the bottle-necks for each other. Therefore, mutual restrictive problems must be solved and optimized. Optical flow is the critical model which to be fully represented in the information transferring as well as radiation energy flowing in dynamic imaging. For agile sensors, especially with wide-field-of view, imaging optical flows may distort and deviate seriously when they perform large angle attitude maneuvering imaging. The phenomena are mainly attributed to the geometrical characteristics of the three-dimensional earth surface as well as the coupled effects due to the complicated relative motion between the sensor and scene. Under this circumstance, velocity fields distribute nonlinearly, the imageries may badly be smeared or probably the geometrical structures are changed since the image velocity matching errors are not having been eliminated perfectly. In this paper, precise imaging optical flow model is established for agile remote sensors, for which optical flows evolving is factorized by two forms, which respectively due to translational movement and image shape changing. Moreover, base on that, agile remote sensors instrumentation was investigated. The main techniques which concern optical flow modeling include integrative design with lightweight star sensors along with micro inertial measurement units and corresponding data fusion, the assemblies of focal plane layout and control, imageries post processing for agile remote sensors etc. Some experiments show that the optical analyzing method is effective to

  18. Low-Drift Flow Sensor with Zero-Offset Thermopile-Based Power Feedback

    CERN Document Server

    Dijkstra, M; De Boer, Meint; Berenschot, J W; Wiegerink, Remco; Elwenspoek, M

    2008-01-01

    A thermal flow sensor has been realised consisting of freely-suspended silicon-rich silicon-nitride microchannels with an integrated Al/poly-Si++ thermopile in combination with up- and downstream Al heater resistors. The inherently zero offset of the thermopile is exploited in a feedback loop controlling the dissipated power in the heater resistors, eliminating inevitable influences of resistance drift and mismatch of the thin-film metal resistors. The control system cancels the flow-induced temperature difference across the thermopile by controlling a power difference between both heater resistors, thereby giving a measure for the flow rate. The flow sensor was characterised for power difference versus water flow rates up to 1.5 ul/min, being in good agreement with a thermal model of the sensor, and the correct low-drift operation of the temperature-balancing control system has been verified.

  19. Imaging dipole flow sources using an artificial lateral-line system made of biomimetic hair flow sensors.

    Science.gov (United States)

    Dagamseh, Ahmad; Wiegerink, Remco; Lammerink, Theo; Krijnen, Gijs

    2013-06-01

    In Nature, fish have the ability to localize prey, school, navigate, etc., using the lateral-line organ. Artificial hair flow sensors arranged in a linear array shape (inspired by the lateral-line system (LSS) in fish) have been applied to measure airflow patterns at the sensor positions. Here, we take advantage of both biomimetic artificial hair-based flow sensors arranged as LSS and beamforming techniques to demonstrate dipole-source localization in air. Modelling and measurement results show the artificial lateral-line ability to image the position of dipole sources accurately with estimation error of less than 0.14 times the array length. This opens up possibilities for flow-based, near-field environment mapping that can be beneficial to, for example, biologists and robot guidance applications.

  20. Simultaneous Moisture Content and Mass Flow Measurements in Wood Chip Flows Using Coupled Dielectric and Impact Sensors

    Directory of Open Access Journals (Sweden)

    Pengmin Pan

    2016-12-01

    Full Text Available An 8-electrode capacitance tomography (ECT sensor was built and used to measure moisture content (MC and mass flow of pine chip flows. The device was capable of directly measuring total water quantity in a sample but was sensitive to both dry matter and moisture, and therefore required a second measurement of mass flow to calculate MC. Two means of calculating the mass flow were used: the first being an impact sensor to measure total mass flow, and the second a volumetric approach based on measuring total area occupied by wood in images generated using the capacitance sensor’s tomographic mode. Tests were made on 109 groups of wood chips ranging in moisture content from 14% to 120% (dry basis and wet weight of 280 to 1100 g. Sixty groups were randomly selected as a calibration set, and the remaining were used for validation of the sensor’s performance. For the combined capacitance/force transducer system, root mean square errors of prediction (RMSEP for wet mass flow and moisture content were 13.42% and 16.61%, respectively. RMSEP using the combined volumetric mass flow/capacitance sensor for dry mass flow and moisture content were 22.89% and 24.16%, respectively. Either of the approaches was concluded to be feasible for prediction of moisture content in pine chip flows, but combining the impact and capacitance sensors was easier to implement. In situations where flows could not be impeded, however, the tomographic approach would likely be more useful.

  1. Modeling, design, fabrication and characterization of a micro Coriolis mass flow sensor

    Science.gov (United States)

    Haneveld, J.; Lammerink, T. S. J.; de Boer, M. J.; Sanders, R. G. P.; Mehendale, A.; Lötters, J. C.; Dijkstra, M.; Wiegerink, R. J.

    2010-12-01

    This paper discusses the modeling, design and realization of micromachined Coriolis mass flow sensors. A lumped element model is used to analyze and predict the sensor performance. The model is used to design a sensor for a flow range of 0-1.2 g h-1 with a maximum pressure drop of 1 bar. The sensor was realized using semi-circular channels just beneath the surface of a silicon wafer. The channels have thin silicon nitride walls to minimize the channel mass with respect to the mass of the moving fluid. Special comb-shaped electrodes are integrated on the channels for capacitive readout of the extremely small Coriolis displacements. The comb-shaped electrode design eliminates the need for multiple metal layers and sacrificial layer etching methods. Furthermore, it prevents squeezed film damping due to a thin layer of air between the capacitor electrodes. As a result, the sensor operates at atmospheric pressure with a quality factor in the order of 40 and does not require vacuum packaging like other micro Coriolis flow sensors. Measurement results using water, ethanol, white gas and argon are presented, showing that the sensor measures true mass flow. The measurement error is currently in the order of 1% of the full scale of 1.2 g h-1.

  2. Self-Powered Triboelectric Micro Liquid/Gas Flow Sensor for Microfluidics.

    Science.gov (United States)

    Chen, Jie; Guo, Hengyu; Zheng, Jiangeng; Huang, Yingzhou; Liu, Guanlin; Hu, Chenguo; Wang, Zhong Lin

    2016-08-23

    Liquid and gas flow sensors are important components of the micro total analysis systems (μTAS) for modern analytical sciences. In this paper, we proposed a self-powered triboelectric microfluidic sensor (TMS) by utilizing the signals produced from the droplet/bubble via the capillary and the triboelectrification effects on the liquid/solid interface for real-time liquid and gas flow detection. By alternating capillary with different diameters, the sensor's detecting range and sensitivity can be adjusted. Both the relationship between the droplet/bubble and capillary size, and the output signal of the sensor are systematically studied. By demonstrating the monitoring of the transfusion process for a patient and the gas flow produced from an injector, it shows that TMS has a great potential in building a self-powered micro total analysis system.

  3. Development of a FBG vortex flow sensor for high-temperature applications

    NARCIS (Netherlands)

    Cheng, L.K.; Schiferli, W.; Nieuwland, R.A.; Franzen, A.; Boer, J.J. den; Jansen, T.H.

    2011-01-01

    A robust fibre optic flow sensor has been developed to measure liquid or gas flows at ambient temperatures up to 300°C and pressures up to 100 bar. While such environmental conditions are typical in pressurized steam systems in the oil and gas industry (downhole and surface), wider applications are

  4. A novel capacitive detection principle for Coriolis mass flow sensors enabling range/sensitivity tuning

    NARCIS (Netherlands)

    Alveringh, Dennis; Groenesteijn, Jarno; Ma, Kechun; Wiegerink, Remco J.; Lötters, Joost Conrad

    2015-01-01

    We report on a novel capacitive detection principle for Coriolis mass flow sensors which allows for one order of magnitude increased sensitivity. The detection principle consists of two pairs of comb-structures: one pair produces two signals with a phase shift directly dependent on the mass flow,

  5. Optical Sensor of Thermal Gas Flow Based on Fiber Bragg Grating

    Science.gov (United States)

    Jiang, Xu; Wang, Keda; Li, Junqing; Zhan, Hui; Song, Zhenan; Che, Guohang; Lyu, Guohui

    2017-01-01

    This paper aims at solving the problem of explosion proof in measurement of thermal gas flow using electronic sensor by presenting a new type of flow sensor by optical fiber heating. A measuring unit based on fiber Bragg grating (FBG) for fluid temperature and a unit for heat dissipation are designed to replace the traditional electronic sensors. The light in C band from the amplified spontaneous emission (ASE) light source is split, with one part used to heat the absorbing coating and the other part used in the signal processing unit. In the heating unit, an absorbing coating is introduced to replace the traditional resistance heating module to minimize the risk of explosion. The measurement results demonstrate a fine consistency between the flow and temperature difference in simulation. The method to enhance the measurement resolution of flow is also discussed. PMID:28212268

  6. Optical Sensor of Thermal Gas Flow Based on Fiber Bragg Grating

    Directory of Open Access Journals (Sweden)

    Xu Jiang

    2017-02-01

    Full Text Available This paper aims at solving the problem of explosion proof in measurement of thermal gas flow using electronic sensor by presenting a new type of flow sensor by optical fiber heating. A measuring unit based on fiber Bragg grating (FBG for fluid temperature and a unit for heat dissipation are designed to replace the traditional electronic sensors. The light in C band from the amplified spontaneous emission (ASE light source is split, with one part used to heat the absorbing coating and the other part used in the signal processing unit. In the heating unit, an absorbing coating is introduced to replace the traditional resistance heating module to minimize the risk of explosion. The measurement results demonstrate a fine consistency between the flow and temperature difference in simulation. The method to enhance the measurement resolution of flow is also discussed.

  7. Sensor Fish: an autonomous sensor package for characterizing complex flow fields and fish passage

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Zhiqun; Martinez, Jayson J.; Lu, Jun

    2016-10-04

    Fish passing through dams or other hydraulic structures may be injured or killed despite advances in turbine design, project operations, and other fish bypass systems. The Sensor Fish (SF) device is an autonomous sensor package that characterizes the physical conditions and stressors to which fish are exposed during passage through hydro facilities. It was designed to move passively as a neutrally buoyant object through severe hydraulic environments, while collecting high-resolution sensor data. Since its first generation1, the SF device has been successfully deployed in many fish passage studies and has evolved to be a major tool for characterizing fish passage conditions during fish passage in the Columbia River Basin. To better accelerate hydropower development, the U.S. Department of Energy Water Power Program provided funding to develop a new generation (Gen 2 SF) to incorporate more capabilities and accommodate a wider range of users over a broader range of turbine designs and operating environments. The Gen 2 SF (Figure 1) is approximately the size and density of a yearling salmon smolt and is nearly neutrally buoyant. It contains three-dimensional (3D) rotation sensors, 3D linear acceleration sensors, a pressure sensor, a temperature sensor, a 3D orientation sensor, a radiofrequency (RF) transmitter, and a recovery module2. A low-power microcontroller collects data from the sensors and stores up to 5 min of data on internal flash memory at a sampling frequency of 2048 Hz. The recovery module makes the SF positively buoyant after a pre-programmed period of time, causing it to float to the surface for recovery.

  8. Nanoimprinted distributed feedback dye laser sensors for high frame rate refractometric imaging of dissolution and fluid flow

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten;

    2015-01-01

    High frame rate refractometric dissolution and fluid flow monitoring in one and two dimensions of space with distributed feedback dye laser sensors is presented. The sensors provide both low detection limits and high spatial resolution. © 2015 OSA.......High frame rate refractometric dissolution and fluid flow monitoring in one and two dimensions of space with distributed feedback dye laser sensors is presented. The sensors provide both low detection limits and high spatial resolution. © 2015 OSA....

  9. Laser Doppler Blood Flow Imaging Using a CMOS Imaging Sensor with On-Chip Signal Processing

    Directory of Open Access Journals (Sweden)

    Cally Gill

    2013-09-01

    Full Text Available The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.

  10. Laser doppler blood flow imaging using a CMOS imaging sensor with on-chip signal processing.

    Science.gov (United States)

    He, Diwei; Nguyen, Hoang C; Hayes-Gill, Barrie R; Zhu, Yiqun; Crowe, John A; Gill, Cally; Clough, Geraldine F; Morgan, Stephen P

    2013-09-18

    The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF) imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.

  11. Laser Doppler Blood Flow Imaging Using a CMOS Imaging Sensor with On-Chip Signal Processing

    Science.gov (United States)

    He, Diwei; Nguyen, Hoang C.; Hayes-Gill, Barrie R.; Zhu, Yiqun; Crowe, John A.; Gill, Cally; Clough, Geraldine F.; Morgan, Stephen P.

    2013-01-01

    The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF) imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue. PMID:24051525

  12. High temperature gradient micro-sensor for wall shear stress and flow direction measurements

    Science.gov (United States)

    Ghouila-Houri, C.; Claudel, J.; Gerbedoen, J.-C.; Gallas, Q.; Garnier, E.; Merlen, A.; Viard, R.; Talbi, A.; Pernod, P.

    2016-12-01

    We present an efficient and high-sensitive thermal micro-sensor for near wall flow parameters measurements. By combining substrate-free wire structure and mechanical support using silicon oxide micro-bridges, the sensor achieves a high temperature gradient, with wires reaching 1 mm long for only 3 μm wide over a 20 μm deep cavity. Elaborated to reach a compromise solution between conventional hot-films and hot-wire sensors, the sensor presents a high sensitivity to the wall shear stress and to the flow direction. The sensor can be mounted flush to the wall for research studies such as turbulence and near wall shear flow analysis, and for technical applications, such as flow control and separation detection. The fabrication process is CMOS-compatible and allows on-chip integration. The present letter describes the sensor elaboration, design, and micro-fabrication, then the electrical and thermal characterizations, and finally the calibration experiments in a turbulent boundary layer wind tunnel.

  13. Extraction and evaluation of gas-flow-dependent features from dynamic measurements of gas sensors array

    Science.gov (United States)

    Kalinowski, Paweł; Woźniak, Łukasz; Jasiński, Grzegorz; Jasiński, Piotr

    2016-11-01

    Gas analyzers based on gas sensors are the devices which enable recognition of various kinds of volatile compounds. They have continuously been developed and investigated for over three decades, however there are still limitations which slow down the implementation of those devices in many applications. For example, the main drawbacks are the lack of selectivity, sensitivity and long term stability of those devices caused by the drift of utilized sensors. This implies the necessity of investigations not only in the field of development of gas sensors construction, but also the development of measurement procedures or methods of analysis of sensor responses which compensate the limitations of sensors devices. One of the fields of investigations covers the dynamic measurements of sensors or sensor-arrays response with the utilization of flow modulation techniques. Different gas delivery patterns enable the possibility of extraction of unique features which improves the stability and selectivity of gas detecting systems. In this article three utilized flow modulation techniques are presented, together with the proposition of the evaluation method of their usefulness and robustness in environmental pollutants detecting systems. The results of dynamic measurements of an commercially available TGS sensor array in the presence of nitrogen dioxide and ammonia are shown.

  14. Lowering the sensory threshold and enhancing the responsivity of biomimetic hair flow sensors by electrostatic spring softening

    NARCIS (Netherlands)

    Droogendijk, H.; Bruinink, C.M.; Sanders, Remco G.P.; Siebelder, Ortwin G.; Krijnen, Gijsbertus J.M.

    2011-01-01

    We report improvements in detection limit and responsivity of biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC voltage to our capacitive flow sensors results in a reduced sensory threshold, which gives an improvement for the flow detection limit of more than 30%.

  15. Sap flow is Underestimated by Thermal Dissipation Sensors due to Alterations of Wood Anatomy

    Science.gov (United States)

    Marañón-Jiménez, S.; Wiedemann, A.; van den Bulcke, J.; Cuntz, M.; Rebmann, C.; Steppe, K.

    2014-12-01

    The thermal dissipation technique (TD) is one of the most commonly adopted methods for sap flow measurements. However, underestimations of up to 60% of the tree transpiration have been reported with this technique, although the causes are not certainly known. The insertion of TD sensors within the stems causes damage of the wood tissue and subsequent healing reactions, changing wood anatomy and likely the sap flow path. However, the anatomical changes in response to the insertion of sap flow sensors and the effects on the measured flow have not been assessed yet. In this study, we investigate the alteration of vessel anatomy on wounds formed around TD sensors. Our main objectives were to elucidate the anatomical causes of sap flow underestimation for ring-porous and diffuse-porous species, and relate these changes to sap flow underestimations. Successive sets of TD probes were installed in early, mid and end of the growing season in Fagus sylvatica (diffuse-porous) and Quercus petraea (ring-porous) trees. They were logged after the growing season and additional sets of sensors were installed in the logged stems with presumably no healing reaction. The wood tissue surrounding each sensor was then excised and analysed by X-ray computed microtomography (X-ray micro CT). This technique allowed the quantification of vessel anatomical characteristics and the reconstruction of the 3-D internal microstructure of the xylem vessels so that extension and shape of the altered area could be determined. Gels and tyloses clogged the conductive vessels around the sensors in both beech and oak. The extension of the affected area was larger for beech although these anatomical changes led to similar sap flow underestimations in both species. The higher vessel size in oak may explain this result and, therefore, larger sap flow underestimation per area of affected conductive tissue. The wound healing reaction likely occurred within the first weeks after sensor installation, which

  16. New Love wave liquid sensor operating at 2 GHz using an integrated micro-flow channel

    Science.gov (United States)

    Assouar, M. B.; Kirsch, P.; Alnot, P.

    2009-09-01

    Surface acoustic wave (SAW) devices based on waveguide modes with shear-horizontal polarization (Love modes) are very promising for sensor applications, especially in liquid media. We present here the realization of a 2 GHz operating frequency sensor based on the SiO2/36YX LiTaO3 structure with an integrated PDMS micro-flow channel and using electron beam lithography to realize the submicronic interdigital transducers. Using our developed sensor operating at 2 GHz, we carried out alternate cycles of nitrogen and water circulating in the PDMS micro-flow channel. We measured an absolute sensitivity of -19 001 Hz mm2 ng-1 due to the interaction of the sensor with water. This sensitivity is higher than that of other devices operating at lower frequencies. The detection mechanism, including gravimetric and permittivity effects at high frequency, will be discussed.

  17. Recent Development in Optical Chemical Sensors Coupling with Flow Injection Analysis

    Directory of Open Access Journals (Sweden)

    Fuensanta Sánchez Rojas

    2006-10-01

    Full Text Available Optical techniques for chemical analysis are well established and sensors based on thesetechniques are now attracting considerable attention because of their importance in applications suchas environmental monitoring, biomedical sensing, and industrial process control. On the other hand,flow injection analysis (FIA is advisable for the rapid analysis of microliter volume samples and canbe interfaced directly to the chemical process. The FIA has become a widespread automatic analyticalmethod for more reasons; mainly due to the simplicity and low cost of the setups, their versatility, andease of assembling. In this paper, an overview of flow injection determinations by using opticalchemical sensors is provided, and instrumentation, sensor design, and applications are discussed. Thiswork summarizes the most relevant manuscripts from 1980 to date referred to analysis using opticalchemical sensors in FIA.

  18. Planar Array Sensor for High-speed Component Distribution Imaging in Fluid Flow Applications

    Directory of Open Access Journals (Sweden)

    Uwe Hampel

    2007-10-01

    Full Text Available A novel planar array sensor based on electrical conductivity measurements ispresented which may be applied to visualize surface fluid distributions. The sensor ismanufactured using printed-circuit board fabrication technology and comprises of 64 x 64interdigital sensing structures. An associated electronics measures the electricalconductivity of the fluid over each individual sensing structure in a multiplexed manner byapplying a bipolar excitation voltage and by measuring the electrical current flowing from adriver electrode to a sensing electrode. After interrogating all sensing structures, a two-dimensional image of the conductivity distribution over a surface is obtained which in turnrepresents fluid distributions over sensor’s surface. The employed electronics can acquire upto 2500 frames per second thus being able to monitor fast transient phenomena. The systemhas been evaluated regarding measurement accuracy and depth sensitivity. Furthermore, theapplication of the sensor in the investigation of two different flow applications is presented.

  19. Bio-inspired MEMS flow and inertial sensors

    NARCIS (Netherlands)

    Droogendijk, Harmen

    2014-01-01

    In biology, mechanosensors, equipped with differing hair-like structures for signal pick-up, are sensitive to a variety of physical quantities like: acceleration, flow, rotational rate, balancing and IR-light. As an example, crickets use filiform hairs for sensing of low-frequency flows to obtain in

  20. Bio-inspired MEMS flow and inertial sensors

    NARCIS (Netherlands)

    Droogendijk, H.

    2014-01-01

    In biology, mechanosensors, equipped with differing hair-like structures for signal pick-up, are sensitive to a variety of physical quantities like acceleration, flow, rotational rate, balancing and IR-light. As an example, crickets use filiform hairs for sensing of low-frequency flows to obtain

  1. Peltier Effect Applied to the Design and Realization of a New Mass Flow Sensor

    OpenAIRE

    Rahmoun, M.; El Hassani, A.; Leclerq, D.; Bendada, E.

    2000-01-01

    The present paper deals with design and realization of a new mass flow sensor using the Peltier effect. The sensor, shaped as a bimetallic circuit includes two continuous parallel strips coated with a great deal of metal plated spots. In such a device, one track performs as a classical thermoelectrical circuitry whose both plated and uncoated parts provide the thermopile junctions. The other strip is subjected to electrical current so as to generate numerous small thermal gradients owing to t...

  2. A Flexible Flow Sensor System and Its Characteristics for Fluid Mechanics Measurements

    Directory of Open Access Journals (Sweden)

    Ruiyi Que

    2009-11-01

    Full Text Available In this paper, we present a novel micromachined hot-film flow sensor system realized by a technique using a film depositing processes and incorporating a standard printed circuit. Sensor electrodes and electronic circuits are preprinted on a flexible substrate of polyimide (PI, i.e., a flexible printed circuit board (FPCB. The sensing element, which is made of Cr/Ni/Pt with a temperature coefficient of resistance around 2,000 ppm/K, is fabricated on the FPCB by either magnetron sputtering technology or pulsed laser deposition (PLD. The sensor can be packed efficiently at high-density and integrated with signal processing circuits without additional pads. A simple fabrication process using mature technique and materials selection guarantees that the time and costs are greatly reduced. Both steady-state and transient characteristics of the sensors are experimentally tested, and the results presented to validate the effectiveness of the sensors.

  3. Feedback Control of Flow Separation Using Plasma Actuator and FBG Sensor

    Directory of Open Access Journals (Sweden)

    Takehiko Segawa

    2016-01-01

    Full Text Available A feedback control system for mitigating flow separation was developed by using a string-type dielectric-barrier-discharge (DBD plasma actuator and a fiber Bragg grating (FBG sensor. Tangential jets were induced from the string-type DBD plasma actuator, which was located at 5% chord from the leading edge of an NACA0024 airfoil. The FBG sensor was attached to the interior surface near the root of the cantilever beam modeled on the pressure surface of the airfoil. The strain at the cantilever root was reflected in the form of Bragg wavelengths (λB detected by the FBG sensor when the cantilever tip was vibrated by the flow near the trailing edge of the airfoil. It was found that calculating running standard deviations in the Bragg wavelength (λB′ detected by the sensor was valuable for judging flow separation in real time. The feedback control of flow separation on the NACA0024 airfoil was successfully demonstrated by setting λB′=0.0028 with periodic flow separations generated in a wind tunnel by oscillating a side wall of the test section with frequency fw=0.42 Hz. It was confirmed that the appearance probability of flow separation tends to decrease with a decrease in the duration for calculating λB′ and with an increase in the duration of jet injection.

  4. Experimental measurement of oil-water two-phase flow by data fusion of electrical tomography sensors and venturi tube

    Science.gov (United States)

    Liu, Yinyan; Deng, Yuchi; Zhang, Maomao; Yu, Peining; Li, Yi

    2017-09-01

    Oil-water two-phase flows are commonly found in the production processes of the petroleum industry. Accurate online measurement of flow rates is crucial to ensure the safety and efficiency of oil exploration and production. A research team from Tsinghua University has developed an experimental apparatus for multiphase flow measurement based on an electrical capacitance tomography (ECT) sensor, an electrical resistance tomography (ERT) sensor, and a venturi tube. This work presents the phase fraction and flow rate measurements of oil-water two-phase flows based on the developed apparatus. Full-range phase fraction can be obtained by the combination of the ECT sensor and the ERT sensor. By data fusion of differential pressures measured by venturi tube and the phase fraction, the total flow rate and single-phase flow rate can be calculated. Dynamic experiments were conducted on the multiphase flow loop in horizontal and vertical pipelines and at various flow rates.

  5. CRYOGENIC DEWAR

    Science.gov (United States)

    Chamberlain, W.H.; Maseck, H.E.

    1964-01-28

    This patent relates to a dewar for storing cryogenic gase and is of the type having aii inner flask surrounded by a vacuum jacket and having a vent spout through which evaporating gas escapes. Heretofore substantial gas loss has resulted from the radiation of heat towards the flask from the warmer outer elements of the dewar. In this invention, the mask is surrounded by a thermally conducting shield which is disposed in the vacuum space between the flask and the outer elements of the dewar. The shield contacts only the vent spout, which is cooled by the evaporating gas, and thus is maintained at a temperature very close to that of the flask itself. Accordingly, heat radiated toward the flask is intercepted and conducted to the evaporating gas rather than being re-radiated towards the hask. In a liquid helium dewar of typical configniration the mention reduces the boil-off rate by approximately one-half.(AEC)

  6. Thermal MEMS flow meter for gaseous working fluids on the basis of the hot-wire thermoanemometric sensor

    Science.gov (United States)

    Tsivinskaya, T. A.; Avaeva, L. G.; Grigoriev, P. V.; Mileshin, S. A.

    2016-10-01

    This paper describes the main principles of constructing innovative MEMS flow meters for gaseous working fluids. MEMS flow meter contains hot-wire thermoanemometrisc sensor which response to the temperature change caused by convective working fluid heat transfer from a hot-wire. The advantages of using hot-wire thermoanemometric sensors were analyzed. The main emphasis of this work is on speed, construction simplicity and small size of the sensor. The new approach to the solution of a problem of sensor output signal relation with the working fluid temperature is presented. This approach is based on adding an extra temperature sensor and a special scheme for thermal compensation to the hot-wire sensor. The temperature scale between temperature sensors (thermistors) corresponds to the flow speed and the flow rate.

  7. Multiplexed fibre optic sensors for monitoring resin infusion, flow, and cure in composite material processing

    Science.gov (United States)

    Chehura, Edmon; Jarzebinska, Renata; Da Costa, Elisabete F. R.; Skordos, Alexandros A.; James, Stephen W.; Partridge, Ivana K.; Tatam, Ralph P.

    2013-04-01

    The infusion, flow and cure of RTM6 resin in a carbon fibre reinforced composite preform have been monitored using a variety of multiplexed fibre optic sensors. Optical fibre Fresnel sensors and tilted fibre Bragg grating (TFBG) sensors were configured to monitor resin infusion/flow in-plane of the component. The results obtained from the different sensors were in good agreement with visual observations. The degree of cure was monitored by Fresnel sensors via a measurement of the refractive index of the resin which was converted to degree of cure using a calibration determined from Differential Scanning Calorimetry. Fibre Bragg grating sensors fabricated in highly linearly birefringent fibre were used to monitor the development of transverse strain during the cure process, revealing through-thickness material shrinkage of about 712 μɛ and residual strain of 223 μɛ. An alternative approach to infusion monitoring, based on an array of multiplexed tapered optical fibre sensors interrogated using optical frequency domain reflectometry, was also investigated in a separate carbon fibre preform that was infused with RTM6 resin.

  8. Fiber optic liquid mass flow sensor and method

    Science.gov (United States)

    Korman, Valentin (Inventor); Gregory, Don Allen (Inventor); Wiley, John T. (Inventor); Pedersen, Kevin W. (Inventor)

    2010-01-01

    A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.

  9. Touch at a distance sensing: lateral-line inspired MEMS flow sensors.

    Science.gov (United States)

    Prakash Kottapalli, Ajay Giri; Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael

    2014-11-07

    Evolution bestowed the blind cavefish with a resourcefully designed lateral-line of sensors that play an essential role in many important tasks including object detection and avoidance, energy-efficient maneuvering, rheotaxis etc. Biologists identified the two types of vital sensors on the fish bodies called the superficial neuromasts and the canal neuromasts that are responsible for flow sensing and pressure-gradient sensing, respectively. In this work, we present the design, fabrication and experimental characterization of biomimetic polymer artificial superficial neuromast micro-sensor arrays. These biomimetic micro-sensors demonstrated a high sensitivity of 0.9 mV/(m s(-1)) and 0.022 V/(m s(-1)) and threshold velocity detection limits of 0.1 m s(-1) and 0.015 m s(-1) in determining air and water flows respectively. Experimental results demonstrate that the biological canal inspired polymer encapsulation on the array of artificial superficial neuromast sensors is capable of filtering steady-state flows that could otherwise significantly mask the relevant oscillatory flow signals of high importance.

  10. Cryogenic needs for future tokamaks

    Science.gov (United States)

    Katheder, H.

    The ITER tokamak is a machine using superconducting magnets. The windings of these magnets will be subjected to high heat loads resulting from a combination of nuclear energy absorption and AC-losses. It is estimated that about 100 kW at 4.5 K are needed. The total cooling mass flow rate will be around 10 - 15 kg/s. In addition to the large cryogenic power required for the superconducting magnets cryogenic power is also needed for refrigerated radiation shield, various cryopumps, fuel processing and test beds. A general description of the overall layout and the envisaged refrigerator cycle, necessary cold pumps and ancillary equipment is given. The basic cryogenic layout for the ITER tokakmak design, as developed during the conceptual design phase and a short overview about existing tokamak designs using superconducting magnets is given.

  11. Fiber optic flow velocity sensor based on an in-fiber integrated Michelson interferometer

    Science.gov (United States)

    Yuan, Libo; Yang, Jun; Liu, Zhihai

    2008-04-01

    A novel fiber optic flow velocity sensor based on a twin-core fiber Michelson interferometer has been proposed and demonstrated. The sensor only is a segment of twin-core fiber acting as cylinder cantilever beam. The force exerted on the cylinder by the flow of a fluid with unknown velocity bends the fiber, which corresponding to the shift of the phase of the twin-core in-fiber integrated Michelson interferometer. This twin-core fiber sensing technique could automatically compensate the variation of environmental temperature and pressure due to both arms of the interferometer would be affected equally by such changes.

  12. Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten

    2015-01-01

    Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution...... and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns...

  13. Heat transfer measurements in fully turbulent flows: basic investigations with an advanced thin foil triple sensor

    Science.gov (United States)

    Mocikat, H.; Herwig, H.

    2008-07-01

    In a former article in this journal a double layer hot film with two 10 μm nickel foils, separated by a 25 μm polyimide foil was introduced as a multi-purpose sensor. Each foil can be operated as a (calibrated) temperature sensor in its passive mode by imposing an electric current small enough to avoid heating by dissipation of electrical energy. Alternatively, however, each foil can also serve as a heater in an active mode with electric currents high enough to cause Joule heating. This double foil sensor can be used as a conventional heat flux sensor in its passive mode when mounted on an externally heated surface. In fully turbulent flows it alternatively can be operated in an active mode on a cold, i.e. not externally heated surface. Then, by heating the upper foil, a local heat transfer is initiated from which the local heat transfer coefficient h can be determined, once the lower foil is heated to the same temperature as the upper one, thus acting as a counter-heater. For further investigations with respect to the underlying sensor concept a triple sensor has been built which consists of three double layer film sensors very close to each other. Various aspects of heat transfer measurements in active modes can be addressed by this sensor.

  14. A high-temperature calorimetric flow sensor employing ion conduction in zirconia

    Science.gov (United States)

    Persson, A.; Lekholm, V.; Thornell, G.; Klintberg, L.

    2015-05-01

    This paper presents the use of the temperature-dependent ion conductivity of 8 mol % yttria-stabilized zirconia (YSZ8) in a miniature high-temperature calorimetric flow sensor. The sensor consists of 4 layers of high-temperature co-fired ceramic (HTCC) YSZ8 tape with a 400 μm wide, 100 μm deep, and 12 500 μm long internal flow channel. Across the center of the channel, four platinum conductors, each 80 μm wide with a spacing of 160 μm, were printed. The two center conductors were used as heaters, and the outer, up- and downstream conductors were used to probe the resistance through the zirconia substrate around the heaters. The thermal profile surrounding the two heaters could be made symmetrical by powering them independently, and hence, the temperature sensing elements could be balanced at zero flow. With nitrogen flowing through the channel, forced convection shifted the thermal profile downstream, and the resistance of the temperature sensing elements diverged. The sensor was characterized at nitrogen flows from 0 to 40 sccm, and resistances at zero-flow from 10 to 50 MΩ. A peak sensitivity of 3.1 MΩ/sccm was obtained. Moreover, the sensor response was found to be linear over the whole flow range, with R2 of around 0.999, and easy to tune with the individual temperature control of the heaters. The ability of the sensor to operate in high temperatures makes it promising for use in different harsh environments, e.g., for close integration with microthrusters.

  15. Numerical Prediction of a Bi-Directional Micro Thermal Flow Sensors

    Directory of Open Access Journals (Sweden)

    M. Al-Amayrah

    2011-09-01

    Full Text Available Thermal flow sensors such as hot-wire anemometer (HWA can be used to measure the flow velocity with certain accuracy. However, HWA can measure the flow velocity without determining the flow direction. Pulsed-Wire Anemometer (PWA with 3 wires can be used to measure flow velocity and flow directions. The present study aims to develop a numerical analysis of unsteady flow around a pulsed hot-wire anemometer using three parallel wires. The pulsed wire which is called the heated wire is located in the middle and the two sensor wires are installed upstream and downstream of the pulsed wire. 2-D numerical models were built and simulated using different wires arrangements. The ratio of the separation distance between the heated wire and sensor wire (x to the diameter of the heated wire (D ratios (x/D was varied between 3.33 and 183.33. The output results are plotted as a function of Peclet number (convection time / diffusion time. It was found that as the ratio of x/D increases, the sensitivity of PWA device to the time of flight decreases. But at the same the reading of the time of flight becomes more accurate, because the effects of the diffusion and wake after the heated wire decrease. Also, a very good agreement has been obtained between the present numerical simulation and the previous experimental data.

  16. Two-Dimensional Automatic Measurement for Nozzle Flow Distribution Using Improved Ultrasonic Sensor

    Directory of Open Access Journals (Sweden)

    Changyuan Zhai

    2015-10-01

    Full Text Available Spray deposition and distribution are affected by many factors, one of which is nozzle flow distribution. A two-dimensional automatic measurement system, which consisted of a conveying unit, a system control unit, an ultrasonic sensor, and a deposition collecting dish, was designed and developed. The system could precisely move an ultrasonic sensor above a pesticide deposition collecting dish to measure the nozzle flow distribution. A sensor sleeve with a PVC tube was designed for the ultrasonic sensor to limit its beam angle in order to measure the liquid level in the small troughs. System performance tests were conducted to verify the designed functions and measurement accuracy. A commercial spray nozzle was also used to measure its flow distribution. The test results showed that the relative error on volume measurement was less than 7.27% when the liquid volume was 2 mL in trough, while the error was less than 4.52% when the liquid volume was 4 mL or more. The developed system was also used to evaluate the flow distribution of a commercial nozzle. It was able to provide the shape and the spraying width of the flow distribution accurately.

  17. Two-dimensional automatic measurement for nozzle flow distribution using improved ultrasonic sensor.

    Science.gov (United States)

    Zhai, Changyuan; Zhao, Chunjiang; Wang, Xiu; Wang, Ning; Zou, Wei; Li, Wei

    2015-10-16

    Spray deposition and distribution are affected by many factors, one of which is nozzle flow distribution. A two-dimensional automatic measurement system, which consisted of a conveying unit, a system control unit, an ultrasonic sensor, and a deposition collecting dish, was designed and developed. The system could precisely move an ultrasonic sensor above a pesticide deposition collecting dish to measure the nozzle flow distribution. A sensor sleeve with a PVC tube was designed for the ultrasonic sensor to limit its beam angle in order to measure the liquid level in the small troughs. System performance tests were conducted to verify the designed functions and measurement accuracy. A commercial spray nozzle was also used to measure its flow distribution. The test results showed that the relative error on volume measurement was less than 7.27% when the liquid volume was 2 mL in trough, while the error was less than 4.52% when the liquid volume was 4 mL or more. The developed system was also used to evaluate the flow distribution of a commercial nozzle. It was able to provide the shape and the spraying width of the flow distribution accurately.

  18. Detection of flow separation and stagnation points using artificial hair sensors

    Science.gov (United States)

    Phillips, D. M.; Ray, C. W.; Hagen, B. J.; Su, W.; Baur, J. W.; Reich, G. W.

    2015-11-01

    Recent interest in fly-by-feel approaches for aircraft control has motivated the development of novel sensors for use in aerial systems. Artificial hair sensors (AHSs) are one type of device that promise to fill a unique niche in the sensory suite for aerial systems. In this work, we investigate the capability of an AHS based on structural glass fibers to directly identify flow stagnation and separation points on a cylindrical domain in a steady flow. The glass fibers are functionalized with a radially aligned carbon nanotube (CNT) forest and elicit a piezoresistive response as the CNT forest impinges on electrodes in a micropore when the hair is deflected due to viscous drag forces. Particle image velocimetry is used to measure the flow field allowing for the resulting moment and force acting on the hair to be correlated with the electrical response. It is demonstrated that the AHS provides estimates for the locations of both the stagnation and separation in steady flow. From this, a simulation of a heading estimation is presented to demonstrate a potential application for hair sensors. These results motivate the construction of large arrays of hair sensors for imaging and resolving flow structures in real time.

  19. Minimal sensor count approach to fuzzy logic rotary blood pump flow control.

    Science.gov (United States)

    Casas, Fernando; Ahmed, Nisar; Reeves, Andrew

    2007-01-01

    A rotary blood pump fuzzy logic flow controller without flow sensors was developed and tested in vitro. The controller, implemented in LabView, was set to maintain a flow set point in the presence of external pressure disturbances. Flow was estimated as a function of measured pump's delta P and speed, using a steady-state, nonlinear approximation. The fuzzy controller used the pump's flow estimate and delta P as feedback variables. The defuzzified control output manipulated the pump speed. Membership functions included flow error, delta P, and pump speed. Experimental runs in a mock loop (water/glycerin 3.5 cPs, 37 degrees C), using the estimated flow, were compared with those using a Transonic flow meter for nine conditions of flow and delta P (4 to 6 L/min, 150 to 350 mm Hg). Pressure disturbances generated by a servo pinch valve ranged from +/-23 to +/-47 mm Hg. Results indicated that the fuzzy controller ably regulated the flow set point to within +/-10% of the baseline even under large swings in pressure. There was no difference in controller performance between the ultrasonic flow measurement and the estimated flow calculation scenarios. These tests demonstrated that the fuzzy controller is capable of rejecting disturbances and regulating flow to acceptable limits while using a flow estimate.

  20. Cryogenic Tracking Detectors

    CERN Multimedia

    Luukka, P R; Tuominen, E M; Mikuz, M

    2002-01-01

    The recent advances in Si and diamond detector technology give hope of a simple solution to the radiation hardness problem for vertex trackers at the LHC. In particular, we have recently demonstrated that operating a heavily irradiated Si detector at liquid nitrogen (LN$_2$) temperature results in significant recovery of Charge Collection Efficiency (CCE). Among other potential benefits of operation at cryogenic temperatures are the use of large low-resistivity wafers, simple processing, higher and faster electrical signal because of higher mobility and drift velocity of carriers, and lower noise of the readout circuit. A substantial reduction in sensor cost could result The first goal of the approved extension of the RD39 program is to demonstrate that irradiation at low temperature in situ during operation does not affect the results obtained so far by cooling detectors which were irradiated at room temperature. In particular we shall concentrate on processes and materials that could significantly reduce th...

  1. MEMS sensors for assessing flow-related control of an underwater biomimetic robotic stingray.

    Science.gov (United States)

    Asadnia, Mohsen; Kottapalli, Ajay Giri Prakash; Haghighi, Reza; Cloitre, Audren; Alvarado, Pablo Valdivia Y; Miao, Jianmin; Triantafyllou, Michael

    2015-05-18

    A major difference between manmade underwater robotic vehicles (URVs) and undersea animals is the dense arrays of sensors on the body of the latter which enable them to execute extreme control of their limbs and demonstrate super-maneuverability. There is a high demand for miniaturized, low-powered, lightweight and robust sensors that can perform sensing on URVs to improve their control and maneuverability. In this paper, we present the design, fabrication and experimental testing of two types of microelectromechanical systems (MEMS) sensors that benefit the situational awareness and control of a robotic stingray. The first one is a piezoresistive liquid crystal polymer haircell flow sensor which is employed to determine the velocity of propagation of the stingray. The second one is Pb(Zr(0.52)Ti(0.48))O3 piezoelectric micro-diaphragm pressure sensor which measures various flapping parameters of the stingray's fins that are key parameters to control the robot locomotion. The polymer flow sensors determine that by increasing the flapping frequency of the fins from 0.5 to 3 Hz the average velocity of the stingray increases from 0.05 to 0.4 BL s(-1), respectively. The role of these sensors in detecting errors in control and functioning of the actuators in performing tasks like flapping at a desired amplitude and frequency, swimming at a desired velocity and direction are quantified. The proposed sensors are also used to provide inputs for a model predictive control which allows the robot to track a desired trajectory. Although a robotic stingray is used as a platform to emphasize the role of the MEMS sensors, the applications can be extended to most URVs.

  2. A method of calibrating wind velocity sensors with a modified gas flow calibrator

    Science.gov (United States)

    Stump, H. P.

    1978-01-01

    A procedure was described for calibrating air velocity sensors in the exhaust flow of a gas flow calibrator. The average velocity in the test section located at the calibrator exhaust was verified from the mass flow rate accurately measured by the calibrator's precision sonic nozzles. Air at elevated pressures flowed through a series of screens, diameter changes, and flow straighteners, resulting in a smooth flow through the open test section. The modified system generated air velocities of 2 to 90 meters per second with an uncertainty of about two percent for speeds below 15 meters per second and four percent for the higher speeds. Wind tunnel data correlated well with that taken in the flow calibrator.

  3. Oil-water two-phase flow measurement with combined ultrasonic transducer and electrical sensors

    Science.gov (United States)

    Tan, Chao; Yuan, Ye; Dong, Xiaoxiao; Dong, Feng

    2016-12-01

    A combination of ultrasonic transducers operated in continuous mode and a conductance/capacitance sensor (UTCC) is proposed to estimate the individual flow velocities in oil-water two-phase flows. Based on the Doppler effect, the transducers measure the flow velocity and the conductance/capacitance sensor estimates the phase fraction. A set of theoretical correlations based on the boundary layer models of the oil-water two-phase flow was proposed to describe the velocity profile. The models were separately established for the dispersion flow and the separate flow. The superficial flow velocity of each phase is calculated with the velocity measured in the sampling volume of the ultrasonic transducer with the phase fraction through the velocity profile models. The measuring system of the UTCC was designed and experimentally verified on a multiphase flow loop. The results indicate that the proposed system and correlations estimate the overall flow velocity at an uncertainty of U J   =  0.038 m s-1, and the water superficial velocity at U Jw   =  0.026 m s-1, and oil superficial velocity at U Jo   =  0.034 m s-1. The influencing factors of uncertainty were analyzed.

  4. In situ permeable flow sensor - OST reference No. 99. Subsurface contaminants focus area

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    This summary reports describes the In Situ Permeable Flow Sensor (ISPFS) developed to directly measure the direction and velocity of groundwater flow at a point in saturated soil sediments. The ISPFS provides information for locating, designing, and monitoring waste disposal sites, and for monitoring remediated waste sites. The design and performance are described and compared to alternative methods. Economic, regulatory, and policy issues are discussed. Applicability of the ISPFS to specific situations is also summarized. 8 refs., 7 figs., 3 tabs.

  5. Wavefront sensors for optical diagnostics in fluid mechanics: Application to heated flow, turbulence and droplet evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Neal, D.R.; O`Hern, T.J.; Torczynski, J.R.; Warren, M.E.; Shul, R. [Sandia National Labs., Albuquerque, NM (United States); McKechnie, T.S. [POD Associates, Inc., Albuquerque, NM (United States)

    1993-09-01

    Optical measurement techniques are extremely useful in fluid mechanics because of their non-invasive nature. However, it is often difficult to separate measurement effects due to pressure, temperature and density in real flows. Using a variation of a Shack-Hartmann wavefront sensor, we have made density measurements that have extremely large dynamic range coupled with excellent sensitivity at high temporal and spatial resolution. We have examined several classes of flow including volumetrically heated gas, turbulence and droplet evaporation.

  6. Dynamic Characterization of a Low Cost Microwave Water-Cut Sensor in a Flow Loop

    KAUST Repository

    Karimi, Muhammad Akram

    2017-03-31

    Inline precise measurement of water fraction in oil (i.e. water-cut [WC]) finds numerous applications in oil and gas industry. This paper presents the characterization of an extremely low cost, completely non-intrusive and full range microwave water-cut sensor based upon pipe conformable microwave T-resonator. A 10″ microwave stub based T-resonator has been implemented directly on the pipe surface whose resonance frequency changes in the frequency band of 90MHz–190MHz (111%) with changing water fraction in oil. The designed sensor is capable of detecting even small changes in WC with a resolution of 0.07% at low WC and 0.5% WC at high WC. The performance of the microwave WC sensor has been tested in an in-house flow loop. The proposed WC sensor has been characterized over full water-cut range (0%–100%) not only in vertical but also in horizontal orientation. The sensor has shown predictable response in both orientations with huge frequency shift. Moreover, flow rate effect has also been investigated on the proposed WC sensor’s performance and it has been found that the sensor’s repeatability is within 2.5% WC for variable flow rates.

  7. Smart monolithic integration of inkjet printed thermal flow sensors with fast prototyping polymer microfluidics

    Science.gov (United States)

    Etxebarria, Ikerne; Elizalde, Jorge; Pacios, Roberto

    2016-08-01

    There is an increasing demand for built-in flow sensors in order to effectively control microfluidic processes due to the high number of available microfluidic applications. The possible solutions should be inexpensive and easy to connect to both, the microscale features and the macro setup. In this paper, we present a novel approach to integrate a printed thermal flow sensor with polymeric microfluidic channels. This approach is focused on merging two high throughput production processes, namely inkjet printing and fast prototyping technologies, in order to produce trustworthy and low cost devices. These two technologies are brought together to obtain a sensor located outside the microfluidic device. This avoids the critical contact between the sensor material and the fluids through the microchannels that can seriously damage the conducting paths under continuous working regimes. In this way, we ensure reliable and stable operation modes. For this application, a silver nanoparticle based ink and cyclic olefin polymer were used. This flow sensor operates linearly in the range of 0-10 μl min-1 for water and 0-20 μl min-1 for ethanol in calorimetric mode. Switching to anemometric mode, the range can be expanded up to 40 μl min-1.

  8. CFD Modeling of Helium Pressurant Effects on Cryogenic Tank Pressure Rise Rates in Normal Gravity

    Science.gov (United States)

    Grayson, Gary; Lopez, Alfredo; Chandler, Frank; Hastings, Leon; Hedayat, Ali; Brethour, James

    2007-01-01

    A recently developed computational fluid dynamics modeling capability for cryogenic tanks is used to simulate both self-pressurization from external heating and also depressurization from thermodynamic vent operation. Axisymmetric models using a modified version of the commercially available FLOW-3D software are used to simulate actual physical tests. The models assume an incompressible liquid phase with density that is a function of temperature only. A fully compressible formulation is used for the ullage gas mixture that contains both condensable vapor and a noncondensable gas component. The tests, conducted at the NASA Marshall Space Flight Center, include both liquid hydrogen and nitrogen in tanks with ullage gas mixtures of each liquid's vapor and helium. Pressure and temperature predictions from the model are compared to sensor measurements from the tests and a good agreement is achieved. This further establishes the accuracy of the developed FLOW-3D based modeling approach for cryogenic systems.

  9. Simulation of Thermo-fluid Interactions in Cryogenic Stage Turbine Startup System Using AUSM+-UP-based Higher-order Accurate Flow Solver

    Directory of Open Access Journals (Sweden)

    Praveen Nair

    2009-05-01

    Full Text Available High-speed turbines are used in upper stage liquid engines of launch vehicles and the most common ones include LH2 and LOX turbines used in the cryogenic stages. The main constraints in the design of turbine system for a liquid engine are thermal loads, mass flow and pressure drops in various systems ahead of the turbine inlet. The temperature of the combustion products/gases reaching the turbine blades must be well below the melting point of the turbine blade material and the mass flow rate must be sufficient to generate the required power. Turbine can be started in two ways, by generating gases using a solid propellant-based spinner motor, and using compressed gases stored in gas bottles. The first method involves design challenges but requires less space and weight. On the other hand, second method is simple but requires more space. Because of the space and weight constraints associated with the upper stages, first method is preferred and discussed in this paper. It consists of a solid propellant-based spinner motor with a convergent-divergent nozzle, a guiding duct connecting nozzle exit, and the turbine inlet manifold in the form of a torroid with nozzle block having 39 guiding nozzles. The combustion products generated by the spinner motor are guided to the manifold through the guiding duct. Inlet manifold acts as a reservoir and supplies hot gases uniformly to the turbine through 39 nozzles. This study addresses the role of  computational fluid dynamics in the design of turbine startup system using unstructured cell-centered AUSM+-UP-based finite volume solver with the twoequation turbulence model. The flow and the thermal characteristics of the solid motor with a convergentdivergent nozzle were studied to evaluate the gas temperature, operating pressure, and flow velocities. The guiding duct along with the inlet manifold was analysed separately to find the drop in temperature and pressure within the system. From the simulation

  10. Ultrasensitive detection of microbial cells using magnetic focus enhanced lateral flow sensors.

    Science.gov (United States)

    Ren, Wen; Cho, Il-Hoon; Zhou, Zhongwu; Irudayaraj, Joseph

    2016-04-01

    We report on an improved lateral flow immunoassay (LFIA) sensor with a magnetic focus for ultrasensitive naked-eye detection of pathogenic microorganisms at a near single cell limit without any pre-enrichment steps, by allowing the magnetic probes to focus the labelled pathogens to the target zone of the LF strip.

  11. Vibration Isolation by an Actively Compliantly Mounted Sensor Applied to a Coriolis Mass-Flow Meter

    NARCIS (Netherlands)

    Ridder, van de L.; Hakvoort, W.B.J.; Dijk, van J.; Lötters, Joost C.; Boer, de A.

    2016-01-01

    In this paper, a vibration isolated design of a Coriolis mass-flow meter (CMFM) is proposed by introducing a compliant connection between the casing and the tube displacement sensors, with the objective to obtain a relative displacement measurement of the fluid conveying tube, dependent on the tube

  12. A micromachined thin-film gas flow sensor for microchemical reactors

    Science.gov (United States)

    Shin, W. C.; Besser, R. S.

    2006-04-01

    As microchemical systems (MCS) have gained in importance since their introduction in the last decade, it has become recognized that appropriate sensing and control capabilities are needed if MCS are to reach their potential. In this context, we present a study of the working behavior of a novel thin-film micro flow sensor which is integrated with a silicon microreactor with a submillimeter channel. A simple-to-fabricate device based on the concept of calorimetric sensing was chosen as a model structure to understand the important factors controlling sensor performance. Various design options for the sensor were explored by the use of computational fluid dynamics simulations. We found that sensitivity depends strongly on certain design factors. In summary, sensitivity is improved with (a) higher values of the resistors that detect flow-induced temperature changes, (b) shorter distances between the resistor that provides a source of heat and the thermally sensitive resistors and (c) higher input power to the heating resistor. Item (a) was found to have by far the strongest effect of the three. Reproducibility tests were conducted and the sensor exhibited consistent performance throughout the entire test range of 0-20 sccm which is an appropriate fit to the flow capacity of the microchannel. Finally, response time was assessed by simulating the transient behavior of the sensor with a thermal capacitance model, which yielded an accurate prediction of the experimental response of the device. The response time is approximately 70 ms at a typical flow rate of 10 sccm. According to the understanding gained from the model, the sensor response time can be improved by reducing the substrate thickness, using a lower density substrate material, and increasing the convective heat transfer coefficient in the channel.

  13. Development of a micro flow sensor for microfluidic systems

    OpenAIRE

    Loane, S; Selvaganapathy, PR; Ching, CY; 3rd Micro and Nano Flows Conference (MNF2011)

    2011-01-01

    This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute. ...

  14. Development of a micro flow sensor for microfluidic systems

    OpenAIRE

    Loane, S; Selvaganapathy, PR; Ching, CY; 3rd Micro and Nano Flows Conference (MNF2011)

    2011-01-01

    This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute. ...

  15. Cavity Ring Down Absorption of O2 in Air as a Temperature Sensor for an Open and a Cryogenic Optical Cavity.

    Science.gov (United States)

    Nyaupane, Parashu R; Perez-Delgado, Yasnahir; Camejo, David; Wright, Lesley M; Manzanares, Carlos E

    2016-06-30

    The A-band of oxygen has been measured at low resolution at temperatures between 90 K and 373 K using the phase shift cavity ring down (PS-CRD) technique. For temperatures between 90 K and 295 K, the PS-CRD technique presented here involves an optical cavity attached to a cryostat. The static cell and mirrors of the optical cavity are all inside a vacuum chamber at the same temperature of the cryostat. The temperature of the cell can be changed between 77 K and 295 K. For temperatures above 295 K, a hollow glass cylindrical tube without windows has been inserted inside an optical cavity to measure the temperature of air flowing through the tube. The cavity consists of two highly reflective mirrors which are mounted parallel to each other and separated by a distance of 93 cm. In this experiment, air is passed through a heated tube. The temperature of the air flowing through the tube is determined by measuring the intensity of the oxygen absorption as a function of the wavenumber. The A-band of oxygen is measured between 298 K and 373 K, with several air flow rates. To obtain the temperature, the energy of the lower rotational state for seven selected rotational transitions is linearly fitted to a logarithmic function that contains the relative intensity of the rotational transition, the initial and final rotational quantum numbers, and the energy of the transition. Accuracy of the temperature measurement is determined by comparing the calculated temperature from the spectra with the temperature obtained from a calibrated thermocouple inserted at the center of the tube. This flowing air temperature sensor will be used to measure the temperatures of cooling air at the input (cold air) and output (hot air) after cooling the blades of a laboratory gas turbine. The results could contribute to improvements in turbine blade cooling design.

  16. Temperature Sensing Solution for Cryogenic Space Engines Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic systems, heavily used in rocket ground testing, space station operations, shuttle launch systems, etc, require a large number of temperature sensors for...

  17. Cryogenic Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The storage of cryogenic propellants is challenging because heat leaks into the cryogenic storage tanks no matter how good the insulation, resulting in a necessity...

  18. Cryogenics a textbook

    CERN Document Server

    Thipse, S S

    2013-01-01

    A Textbook covers lucidly various cryogenic applications including cryogenic engines and space and electronic applications. Importance of cryogenic engines in space propulsion, complete thermodynamic analysis of cryogenic systems with special emphasis on cryogenic cycles, Dewar vessels used to store cryogenic fluids and their applications in various industries have also been discussed in detail. Explanation of Superconductivity and its applications with a description of various Cryocoolers used in industry has also been provided with extensive details. Further technical information on cryogens has been specified alongwith the vacuum technology which has been sufficiently described with examples. Science of Cryonics has been elaborated and all aspects of technology related to functioning of cryogenic plants and their construction including valves, pipes has been incorporated in this book.

  19. Energy Efficient Cryogenics

    Science.gov (United States)

    Meneghelli, Barry J.; Notardonato, William; Fesmire, James E.

    2016-01-01

    The Cryogenics Test Laboratory, NASA Kennedy Space Center, works to provide practical solutions to low-temperature problems while focusing on long-term technology targets for the energy-efficient use of cryogenics on Earth and in space.

  20. Interfacial area and two-phase flow structure development measured by a double-sensor probe

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Waihung; Revankar, S.T.; Ishii, Yoshihiko; Ishii, Mamoru

    1992-06-01

    In this report, we studied the local phasic characters of dispersed flow regime both at the entrance and at the fully developed regions. Since the dispersed phase is distributed randomly in the medium and enclosed in relatively small interfaces, the phasic measurement becomes difficult to obtain. Local probe must be made with a miniaturized sensor in order to reduce the interface distortion. The double-sensor resistivity probe has been widely used in local void fraction and interface velocity measurements because the are small in comparison with the interfaces. It has been tested and proved to be an accurate local phasic measurement tool. In these experiments, a double-sensor probe was employed to measure the local void fraction and interface velocity in an air-water system. The test section was flow regime can be determined by visualization. Furthermore, local phasic measurements can be verified by photographic studies. We concentrated our study on the bubbly flow regime only. The local measurements were conducted at two axial locations, L/D = 8 and 60, in which the first measurement represents the entrance region where the flow develops, and the second measurement represents the fully developed flow region where the radial profile does not change as the flow moves along the axial direction. Four liquid flow rates were chosen in combination with four different gas injection rates. The superficial liquid velocities were j{sub t} = 1.0, 0.6,0.4, and 0.1 m/s and superficial gas velocities were j{sub g} = 0.0965, 0.0696, 0.0384, and 0.0192 m/s. These combinations put the two-phase flow well in the bubbly flow regime. In this sequence of phenomenological studies, the local void fraction, interface area concentration, sauter mean diameter, bubble velocity and bubble frequency were measured.

  1. Experimental studies on pressure drop characteristics of cryogenic cross-counter flow coiled finned tube heat exchangers

    Science.gov (United States)

    Gupta, Prabhat Kumar; Kush, P. K.; Tiwari, Ashesh

    2010-04-01

    Cross-counter flow coiled finned tube heat exchangers used in medium capacity helium liquefiers/refrigerators were developed in our lab. These heat exchangers were developed using integrated low finned tubes. Experimental studies have been performed to know the pressure drop characteristics of tube side and shell side flow of these heat exchangers. All experiments were performed at room temperature in the Reynolds number range of 3000-30,000 for tube side and 25-155 for shell side. The results of present experiments indicate that available correlations for tube side can not be used for prediction of tube side pressure drop data due to complex surface formation at inner side of tube during formation of fins over the outer surface. Results also indicate that surface roughness effect becomes more pronounced as the value of di/ D m increases. New correlations based on present experimental data are proposed for predicting the friction factors for tube side and shell side.

  2. Cryogenic immersion microscope

    Science.gov (United States)

    Le Gros, Mark; Larabell, Carolyn A.

    2010-12-14

    A cryogenic immersion microscope whose objective lens is at least partially in contact with a liquid reservoir of a cryogenic liquid, in which reservoir a sample of interest is immersed is disclosed. When the cryogenic liquid has an index of refraction that reduces refraction at interfaces between the lens and the sample, overall resolution and image quality are improved. A combination of an immersion microscope and x-ray microscope, suitable for imaging at cryogenic temperatures is also disclosed.

  3. Screen-printed sensor for batch and flow injection potentiometric chromium(VI) monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Moreno, Raul A.; Gismera, M.J.; Sevilla, M.T.; Procopio, Jesus R. [Facultad de Ciencias, Universidad Autonoma de Madrid, Departamento de Quimica Analitica y Analisis Instrumental, Madrid (Spain)

    2010-05-15

    A disposable screen-printed electrode was designed and evaluated for direct detection of chromium(VI) in batch and flow analysis. The carbon screen-printed electrode was modified with a graphite-epoxy composite. The optimal graphite-epoxy matrix contains 37.5% graphite powder, 12.5% diphenylcarbohydrazide, a selective compound for chromium(VI), and 50% epoxy resin. The principal analytical parameters of the potentiometric response in batch and flow analysis were optimized and calculated. The screen-printed sensor exhibits a response time of 20 {+-} 1 s. In flow analysis, the analytical frequency of sampling is 70 injections per hour using 0.1 M NaNO{sub 3} solution at pH 3 as the carrier, a flow rate of 2.5 mL.min{sup -1}, and an injection sample volume of 0.50 mL. The sensor shows potentiometric responses that are very selective for chromium(VI) ions and optimal detection limits in both static mode (2.1 x 10{sup -7} M) and online analysis (9.4 x 10{sup -7} M). The disposable potentiometric sensor was employed to determine toxicity levels of chromium(VI) in mineral, tap, and river waters by flow-injection potentiometry and batch potentiometry. Chromium(VI) determination was also carried out with successful results in leachates from municipal solid waste landfills. (orig.)

  4. Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten;

    2015-01-01

    and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns......Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution....... The unique feature of the presented method is a high frame rate of up to 20 Hz, which is proven to enable the monitoring of fast flow of a sucrose solution jet into pure water. (C) 2015 Optical Society of America...

  5. A MEMS-based Air Flow Sensor with a Free-standing Micro-cantilever Structure

    Directory of Open Access Journals (Sweden)

    Che-Ming Chiang

    2007-10-01

    Full Text Available This paper presents a micro-scale air flow sensor based on a free-standingcantilever structure. In the fabrication process, MEMS techniques are used to deposit asilicon nitride layer on a silicon wafer. A platinum layer is deposited on the silicon nitridelayer to form a piezoresistor, and the resulting structure is then etched to create afreestanding micro-cantilever. When an air flow passes over the surface of the cantileverbeam, the beam deflects in the downward direction, resulting in a small variation in theresistance of the piezoelectric layer. The air flow velocity is determined by measuring thechange in resistance using an external LCR meter. The experimental results indicate that theflow sensor has a high sensitivity (0.0284 ω/ms-1, a high velocity measurement limit (45ms-1 and a rapid response time (0.53 s.

  6. Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor.

    Science.gov (United States)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten; Dufva, Martin; Kristensen, Anders

    2015-03-09

    Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns. The unique feature of the presented method is a high frame rate of up to 20 Hz, which is proven to enable the monitoring of fast flow of a sucrose solution jet into pure water.

  7. Wide Range Flow and Heat Flux Sensors for In-Flight Flow Characterization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The tracking of critical flow features (CFFs) such as stagnation point, flow separation, shock, and transition in flight provides insight into actual aircraft...

  8. Visual-Inspection Probe For Cryogenic Chamber

    Science.gov (United States)

    Friend, Steve; Valenzuela, James; Yoshinaga, Jay

    1990-01-01

    Visual-inspection probe that resembles borescope enables observer at ambient temperature to view objects immersed in turbulent flow of liquid oxygen, liquid nitrogen, or other cryogenic fluid. Design of probe fairly conventional, except special consideration given to selection of materials and to thermal expansion to provide for expected range of operating temperatures. Penetrates wall of cryogenic chamber to provide view of interior. Similar probe illuminates scene. View displayed on video monitor.

  9. Investigation of non-specific signals in nanoporous flow-through and flow-over based sensors.

    Science.gov (United States)

    Kumar, Neeraj; Froner, Elena; Guider, Romain; Scarpa, Marina; Bettotti, Paolo

    2014-03-21

    Porous materials are ideal hosts to fabricate high sensitivity devices. Their large specific area and the possibility to modify the type and the strength of the matrix-analyte interactions allow the realization of sensors with finely tailored characteristics. In this article, we investigate how mass transport across the nanoporous structure influences the response due to the non-specific signal by comparing flow-through versus flow-over geometries. We observed a systematic overestimation of the sensitivity for porous substrate devices made of closed-ended pores compared with open-ended pore ones. Our analysis shows that such an effect is due to (unbound) analytes or contaminants that remain trapped within the pores and are not removed by rinsing of the sample. This result was verified by measuring similar samples in both flow through and flow over configurations, as well as their residual response after blockage of all their active sites. We also notice that sensors based on free-standing membranes show similar results independent of the fact that mass transport is induced by either an external pressure source or simply by Brownian motions.

  10. A single-element, thermal, flow-velocity sensor with wide dynamic range

    Science.gov (United States)

    Al-Salaymeh, A.; Durst, F.; Gad-El-Hak, M.

    2001-11-01

    Thermal flow sensors with a wide dynamic range approaching 1:1000 are presently not available in spite of the large demand for such sensors in practical fluid flow measurements. During the last meeting (paper JG4, Bul. Am. Phys. Soc. 45, no. 9, p. 141, 2000), we described such a probe consisting of a minute wire heated using sinusoidal alternating current and two sensing wires acting as resistance thermometers and set parallel to, and at a small distance on either side of, the pulsed wire. Herein we detail the development of a single wire heated using square waves of electrical current. The elimination of the sensing wires reduces the complexity as well as the cost of the sensor and improves its spatial resolution. Unlike time-of-flight sensors, however, the present single-element sensor is sensitive to the physical properties and temperature of the ambient fluid. The present device is suited for measuring slowly-varying unidirectional flows over a very wide dynamic range. For a given current amplitude and frequency, the nominal output of the single sensor is the increase in wire temperature (or resistance) between times just before the leading edge of the current pulse and just after the trailing edge of the pulse. In practice, an integral of the resistance over the pulse duration is computed and averaged over several pulses. This output is a function of the wire’s time constant or thermal inertia and thus of the flow speed as well as the heat convected from the heated wire to the flow. We exploit the fact that the time constant decreases as the flow speed increases while the rate of heat transfer increases. At very low flow speeds, the response is determined almost entirely by the time constant whereas at high speeds the device acts almost like a constant-current hot-wire anemometer. At low speeds, therefore, the wire thermal inertia augments the output signal of the basic hot wire increasing its speed range and sensitivity above that of a conventional hot

  11. Hybridized electromagnetic-triboelectric nanogenerator for scavenging air-flow energy to sustainably power temperature sensors.

    Science.gov (United States)

    Wang, Xue; Wang, Shuhua; Yang, Ya; Wang, Zhong Lin

    2015-04-28

    We report a hybridized nanogenerator with dimensions of 6.7 cm × 4.5 cm × 2 cm and a weight of 42.3 g that consists of two triboelectric nanogenerators (TENGs) and two electromagnetic generators (EMGs) for scavenging air-flow energy. Under an air-flow speed of about 18 m/s, the hybridized nanogenerator can deliver largest output powers of 3.5 mW for one TENG (in correspondence of power per unit mass/volume: 8.8 mW/g and 14.6 kW/m(3)) at a loading resistance of 3 MΩ and 1.8 mW for one EMG (in correspondence of power per unit mass/volume: 0.3 mW/g and 0.4 kW/m(3)) at a loading resistance of 2 kΩ, respectively. The hybridized nanogenerator can be utilized to charge a capacitor of 3300 μF to sustainably power four temperature sensors for realizing self-powered temperature sensor networks. Moreover, a wireless temperature sensor driven by a hybridized nanogenerator charged Li-ion battery can work well to send the temperature data to a receiver/computer at a distance of 1.5 m. This work takes a significant step toward air-flow energy harvesting and its potential applications in self-powered wireless sensor networks.

  12. The nucleus of endothelial cell as a sensor of blood flow direction

    Directory of Open Access Journals (Sweden)

    Eugene Tkachenko

    2013-08-01

    Hemodynamic shear stresses cause endothelial cells (ECs to polarize in the plane of the flow. Paradoxically, under strong shear flows, ECs disassemble their primary cilia, common sensors of shear, and thus must use an alternative mechanism of sensing the strength and direction of flow. In our experiments in microfluidic perfusion chambers, confluent ECs developed planar cell polarity at a rate proportional to the shear stress. The location of Golgi apparatus and microtubule organizing center was biased to the upstream side of the nucleus, i.e. the ECs polarized against the flow. These in vitro results agreed with observations in murine blood vessels, where EC polarization against the flow was stronger in high flow arteries than in veins. Once established, flow-induced polarization persisted over long time intervals without external shear. Transient destabilization of acto-myosin cytoskeleton by inhibition of myosin II or depolymerization of actin promoted polarization of EC against the flow, indicating that an intact acto-myosin cytoskeleton resists flow-induced polarization. These results suggested that polarization was induced by mechanical displacement of EC nuclei downstream under the hydrodynamic drag. This hypothesis was confirmed by the observation that acute application of a large hydrodynamic force to ECs resulted in an immediate downstream displacement of nuclei and was sufficient to induce persistent polarization. Taken together, our data indicate that ECs can sense the direction and strength of blood flow through the hydrodynamic drag applied to their nuclei.

  13. Two-phase flow patterns characteristics analysis based on image and conductance sensors

    Science.gov (United States)

    Wang, Zhenya; Jin, Ningde; Wang, Chun; Wang, Jinxiang

    2008-10-01

    In order to study the temporal and spatial evolution characteristics of gas-liquid two-phase flow pattern, the two-phase flow monitoring system composed of high-speed dynamic camera and Vertical Multi-Electrode Array conductance sensor (VMEA) was utilized to shoot dynamic images and acquire the conductance fluctuating signals of 5 typical vertical gas-liquid two-phase flow patterns in a 125mm i.d. upward pipe. Gray level co-occurrence matrix (GLCM) was used to extract four time-varying characteristic parameter indices which represented different flow image texture structures and also Lempel-Ziv complexity of them were calculated. Then the transition of flow structure and flow property were comprehensively analyzed, combining the result derived from image information with recurrence plots (RPs) and Lempel-Ziv complexity of conductance fluctuating signals. The study showed that the line texture structure of RPs enabled to indicate flow pattern characteristics; the flow image texture structure characteristic parameters sequence described the variance of flow structure and dynamical complexity of different flow patterns.

  14. Design Issues for Low Power Integrated Thermal Flow Sensors with Ultra-Wide Dynamic Range and Low Insertion Loss

    Directory of Open Access Journals (Sweden)

    Paolo Bruschi

    2012-04-01

    Full Text Available Flow sensors are the key elements in most systems for monitoring and controlling fluid flows. With the introduction of MEMS thermal flow sensors, unprecedented performances, such as ultra wide measurement ranges, low power consumptions and extreme miniaturization, have been achieved, although several critical issues have still to be solved. In this work, a systematic approach to the design of integrated thermal flow sensors, with specification of resolution, dynamic range, power consumption and pressure insertion loss is proposed. All the critical components of the sensors, namely thermal microstructure, package and read-out interface are examined, showing their impact on the sensor performance and indicating effective optimization strategies. The proposed design procedures are supported by experiments performed using a recently developed test chip,including several different sensing structures and a flexible electronic interface.

  15. A New Method for Measurement of Helium Mass Flow Rate in the Cryogenic System of TORE SUPRA

    Institute of Scientific and Technical Information of China (English)

    Ouyang Zhengrong; Pascal Reynaud

    2005-01-01

    The TORE SUPRA Tokamak was built by EURATOM-CEA association. The NbTi conductor of superconducting coils is inserted in a tight enclosure filled with pressurized superfluid helium of 0.125 MPa at 1.8 K [1]. The thick casing is cooled to 4.5 K by 1.8 MPa in 4.5 K supercritical helium circulation. Around this thick casing, a 80 K thermal shield protects the parts at very low temperatures from the thermal radiation, which is cooled by pressurized helium at 80 K and 1.8 MPa. A new measurement method for helium mass flow rate of 80 K shield and 4.5 K casing is described in this paper. The commissioning was done on the two helium loops of the cryoplant: the supercritical 4.5 K thick casing and 80 K shields. The purpose is to improve control of the 4.5 K and 80 K refrigeration loops.

  16. Cryogen Safety Course 8876

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-13

    Cryogenics (from the Greek word κρvoζ, meaning frost or icy cold) is the study of the behavior of matter at very cold temperatures. The purpose of this course is to provide trainees with an introduction to cryogen use, the hazards and potential accidents related to cryogen systems, cryogen safety components, and the requirements that govern the design and use of cryogen systems at Los Alamos National Laboratory (LANL). The knowledge you gain will help you keep your workplace safe for yourself and your coworkers.

  17. Laser Doppler blood flow complementary metal oxide semiconductor imaging sensor with analog on-chip processing.

    Science.gov (United States)

    Gu, Quan; Hayes-Gill, Barrie R; Morgan, Stephen P

    2008-04-20

    A 4 x 4 pixel array with analog on-chip processing has been fabricated within a 0.35 mum complementary metal oxide semiconductor process as a prototype sensor for laser Doppler blood flow imaging. At each pixel the bandpass and frequency weighted filters necessary for processing laser Doppler blood flow signals have been designed and fabricated. Because of the space constraints of implementing an accurate omega(0.5) filter at the pixel level, this has been approximated using the "roll off" of a high-pass filter with a cutoff frequency set at 10 kHz. The sensor has been characterized using a modulated laser source. Fixed pattern noise is present that is demonstrated to be repeatable across the array and can be calibrated. Preliminary blood flow results on a finger before and after occlusion demonstrate that the sensor array provides the potential for a system that can be scaled to a larger number of pixels for blood flow imaging.

  18. [Comparision of forced expiratory time, recorded by two spirometers with flow sensors of various types, and acoustic duration of tracheal forced expiratory noises].

    Science.gov (United States)

    Malaeva, V V; Pochekutova, I A; Korenbaum, V I

    2015-01-01

    In the sample of 44 volunteers forced expiratory time values obtained in spirometers, equipped with flow sensor of Lilly type and turbine flow sensor, and acoustic duration of tracheal forced expiratory noises are compared. It is shown that spirometric forced expiratory time is dependent on flow sensor type. Therefore it can't be used in diagnostic aims.

  19. A two-dimensional flow sensor with integrated micro thermal sensing elements and a back propagation neural network.

    Science.gov (United States)

    Que, Ruiyi; Zhu, Rong

    2013-12-31

    This paper demonstrates a novel flow sensor with two-dimensional 360° direction sensitivity achieved with a simple structure and a novel data fusion algorithm. Four sensing elements with roundabout wires distributed in four quadrants of a circle compose the sensor probe, and work in constant temperature difference (CTD) mode as both Joule heaters and temperature detectors. The magnitude and direction of a fluid flow are measured by detecting flow-induced temperature differences among the four elements. The probe is made of Ti/Au thin-film with a diameter of 2 mm, and is fabricated using micromachining techniques. When a flow goes through the sensor, the flow-induced temperature differences are detected by the sensing elements that also serve as the heaters of the sensor. By measuring the temperature differences among the four sensing elements symmetrically distributed in the sensing area, a full 360° direction sensitivity can be obtained. By using a BP neural network to model the relationship between the readouts of the four sensor elements and flow parameters and execute data fusion, the magnitude and direction of the flow can be deduced. Validity of the sensor design was proven through both simulations and experiments. Wind tunnel experimental results show that the measurement accuracy of the airflow speed reaches 0.72 m/s in the range of 3 m/s-30 m/s and the measurement accuracy of flow direction angle reaches 1.9° in the range of 360°.

  20. A Two-Dimensional Flow Sensor with Integrated Micro Thermal Sensing Elements and a Back Propagation Neural Network

    Directory of Open Access Journals (Sweden)

    Ruiyi Que

    2013-12-01

    Full Text Available This paper demonstrates a novel flow sensor with two-dimensional 360° direction sensitivity achieved with a simple structure and a novel data fusion algorithm. Four sensing elements with roundabout wires distributed in four quadrants of a circle compose the sensor probe, and work in constant temperature difference (CTD mode as both Joule heaters and temperature detectors. The magnitude and direction of a fluid flow are measured by detecting flow-induced temperature differences among the four elements. The probe is made of Ti/Au thin-film with a diameter of 2 mm, and is fabricated using micromachining techniques. When a flow goes through the sensor, the flow-induced temperature differences are detected by the sensing elements that also serve as the heaters of the sensor. By measuring the temperature differences among the four sensing elements symmetrically distributed in the sensing area, a full 360° direction sensitivity can be obtained. By using a BP neural network to model the relationship between the readouts of the four sensor elements and flow parameters and execute data fusion, the magnitude and direction of the flow can be deduced. Validity of the sensor design was proven through both simulations and experiments. Wind tunnel experimental results show that the measurement accuracy of the airflow speed reaches 0.72 m/s in the range of 3 m/s–30 m/s and the measurement accuracy of flow direction angle reaches 1.9° in the range of 360°.

  1. Development and evaluation of virtual refrigerant mass flow sensors for fault detection and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woohyun; Braun, J.

    2016-03-05

    Refrigerant mass flow rate is an important measurement for monitoring equipment performance and enabling fault detection and diagnostics. However, a traditional mass flow meter is expensive to purchase and install. A virtual refrigerant mass flow sensor (VRMF) uses a mathematical model to estimate flow rate using low-cost measurements and can potentially be implemented at low cost. This study evaluates three VRMFs for estimating refrigerant mass flow rate. The first model uses a compressor map that relates refrigerant flow rate to measurements of inlet and outlet pressure, and inlet temperature measurements. The second model uses an energy-balance method on the compressor that uses a compressor map for power consumption, which is relatively independent of compressor faults that influence mass flow rate. The third model is developed using an empirical correlation for an electronic expansion valve (EEV) based on an orifice equation. The three VRMFs are shown to work well in estimating refrigerant mass flow rate for various systems under fault-free conditions with less than 5% RMS error. Each of the three mass flow rate estimates can be utilized to diagnose and track the following faults: 1) loss of compressor performance, 2) fouled condenser or evaporator filter, 3) faulty expansion device, respectively. For example, a compressor refrigerant flow map model only provides an accurate estimation when the compressor operates normally. When a compressor is not delivering the expected flow due to a leaky suction or discharge valve or other internal fault, the energy-balance or EEV model can provide accurate flow estimates. In this paper, the flow differences provide an indication of loss of compressor performance and can be used for fault detection and diagnostics.

  2. Long-period fiber grating sensors for the measurement of liquid level and fluid-flow velocity.

    Science.gov (United States)

    Wang, Jian-Neng; Luo, Ching-Ying

    2012-01-01

    This paper presents the development and assessment of two types of Long Period Fiber Grating (LPFG)-based sensors including a mobile liquid level sensor and a reflective sensor for the measurement of liquid level and fluid-flow velocity. Shewhart control charts were used to assess the liquid level sensing capacity and reliability of the mobile CO(2)-laser engraved LPFG sensor. There were ten groups of different liquid level experiment and each group underwent ten repeated wavelength shift measurements. The results showed that all measurands were within the control limits; thus, this mobile sensor was reliable and exhibited at least 100-cm liquid level measurement capacity. In addition, a reflective sensor consisting of five LPFGs in series with a reflective end has been developed to evaluate the liquid level and fluid-flow velocity. These five LPFGs were fabricated by the electrical arc discharge method and the reflective end was coated with silver by Tollen's test. After each liquid level experiment was performed five times, the average values of the resonance wavelength shifts for LPFG Nos. 1-5 were in the range of 1.35-9.14 nm. The experimental findings showed that the reflective sensor could be used to automatically monitor five fixed liquid levels. This reflective sensor also exhibited at least 100-cm liquid level measurement capacity. The mechanism of the fluid-flow velocity sensor was based on analyzing the relationship among the optical power, time, and the LPFG's length. There were two types of fluid-flow velocity measurements: inflow and drainage processes. The differences between the LPFG-based fluid-flow velocities and the measured average fluid-flow velocities were found in the range of 8.7-12.6%. For the first time to our knowledge, we have demonstrated the feasibility of liquid level and fluid-flow velocity sensing with a reflective LPFG-based sensor without modifying LPFGs or coating chemical compounds.

  3. A Flow-Partitioned Unequal Clustering Routing Algorithm for Wireless Sensor Networks

    OpenAIRE

    Jian Peng; Xiaohai Chen; Tang Liu

    2014-01-01

    Energy efficiency and energy balance are two important issues for wireless sensor networks. In previous clustering routing algorithms, multihop transmission, sleep scheduling, and unequal clustering are always used to improve energy efficiency and energy balance. In these algorithms, only the cluster heads share the burden of data forwarding in each round. In this paper, we propose a flow-partitioned unequal clustering routing (FPUC) algorithm to achieve better energy efficiency and energy ba...

  4. Traffic flow collection wireless sensor network node for intersection light control

    Science.gov (United States)

    Li, Xu; Li, Xue

    2011-10-01

    Wireless sensor network (WSN) is expected to be deployed in intersection to monitor the traffic flow continuously, and the monitoring datum can be used as the foundation of traffic light control. In this paper, a WSN based on ZigBee protocol for monitoring traffic flow is proposed. Structure, hardware and work flow of WSN nodes are designed. CC2431 from Texas Instrument is chosen as the main computational and transmission unit, and CC2591 as the amplification unit. The stability experiment and the actual environment experiment are carried out in the last of the paper. The results of experiments show that WSN has the ability to collect traffic flow information quickly and transmit the datum to the processing center in real time.

  5. The cryogenic control system of BEPCⅡ

    Institute of Scientific and Technical Information of China (English)

    LI Gang; WANG Ke-Xiang; ZHAO Ji-Jiu; YUE Ke-Juan; DAI Ming-Sui; HUANG Yi-Ling; JIANG Bo

    2008-01-01

    A superconducting cryogenic system has been designed and deployed in the Beijing Electron-Positron Collider Upgrade Project(BEPCⅡ).The system consists of a Siemens PLC(ST-PLC,Programmable Logic Controller)for the compressor control,an Allen Bradley(AB)PLC for the cryogenic equipments,and the Experimental Physics and Industrial Control System(EPICS)that integrates the PLCs.The system fully automates the superconducting cryogenic control with process control,PID(Proportional-Integral-Differential)control loops,real-time data access and data storage,alarm handler and human machine interface.It is capable of automatic recovery as well.This paper describes the BEPCⅡ cryogenic control system,data communication between ST-PLC and EPICS Input/Output Controllers(IOCs),and the integration of the flow control,the low level interlock,the AB-PLC,and EPICS.

  6. The cryogenic control system of BEPCII

    Science.gov (United States)

    Li, Gang; Wang, Ke-Xiang; Zhao, Ji-Jiu; Yue, Ke-Juan; Dai, Ming-Hui; Huang, Yi-Ling; Jiang, Bo

    2008-04-01

    A superconducting cryogenic system has been designed and deployed in the Beijing Electron- Positron Collider Upgrade Project (BEPCII). The system consists of a Siemens PLC (S7-PLC, Programmable Logic Controller) for the compressor control, an Allen Bradley (AB) PLC for the cryogenic equipments, and the Experimental Physics and Industrial Control System (EPICS) that integrates the PLCs. The system fully automates the superconducting cryogenic control with process control, PID (Proportional-Integral-Differential) control loops, real-time data access and data storage, alarm handler and human machine interface. It is capable of automatic recovery as well. This paper describes the BEPCII cryogenic control system, data communication between S7-PLC and EPICS Input/Output Controllers (IOCs), and the integration of the flow control, the low level interlock, the AB-PLC, and EPICS.

  7. Temperature measurements with two different IR sensors in a continuous-flow microwave heated system.

    Science.gov (United States)

    Rydfjord, Jonas; Svensson, Fredrik; Fagrell, Magnus; Sävmarker, Jonas; Thulin, Måns; Larhed, Mats

    2013-01-01

    In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe), thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications.

  8. Performances of Three Miniature Bio-inspired Optic Flow Sensors under Natural Conditions

    Directory of Open Access Journals (Sweden)

    Stéphane Viollet

    2011-02-01

    Full Text Available Considerable attention has been paid during the last decade to vision-based navigation systems based on optic flow (OF cues. OF-based systems have been implemented on an increasingly large number of sighted autonomous robotic platforms. Nowadays, the OF is measured using conventional cameras, custom-made sensors and even optical mouse chips. However, very few studies have dealt so far with the reliability of these OF sensors in terms of their precision, range and sensitivity to illuminance variations. Three miniature custom-made OF sensors developed at our laboratory, which were composed of photosensors connected to an OF processing unit were tested and compared in this study, focusing on their responses and characteristics in real indoor and outdoor environments in a large range of illuminance. It was concluded that by combining a custom-made aVLSI retina equipped with Adaptive Pixels for Insect-based Sensor (APIS with a bio-inspired visual processing system, it is possible to obtain highly effective miniature sensors for measuring the OF under real environmental conditions.

  9. Rolled-up magnetic sensor: nanomembrane architecture for in-flow detection of magnetic objects.

    Science.gov (United States)

    Mönch, Ingolf; Makarov, Denys; Koseva, Radinka; Baraban, Larysa; Karnaushenko, Daniil; Kaiser, Claudia; Arndt, Karl-Friedrich; Schmidt, Oliver G

    2011-09-27

    Detection and analysis of magnetic nanoobjects is a crucial task in modern diagnostic and therapeutic techniques applied to medicine and biology. Accomplishment of this task calls for the development and implementation of electronic elements directly in fluidic channels, which still remains an open and nontrivial issue. Here, we present a novel concept based on rolled-up nanotechnology for fabrication of multifunctional devices, which can be straightforwardly integrated into existing fluidic architectures. We apply strain engineering to roll-up a functional nanomembrane consisting of a magnetic sensor element based on [Py/Cu](30) multilayers, revealing giant magnetoresistance (GMR). The comparison of the sensor's characteristics before and after the roll-up process is found to be similar, allowing for a reliable and predictable method to fabricate high-quality ultracompact GMR devices. The performance of the rolled-up magnetic sensor was optimized to achieve high sensitivity to weak magnetic fields. We demonstrate that the rolled-up tube itself can be efficiently used as a fluidic channel, while the integrated magnetic sensor provides an important functionality to detect and respond to a magnetic field. The performance of the rolled-up magnetic sensor for the in-flow detection of ferromagnetic CrO(2) nanoparticles embedded in a biocompatible polymeric hydrogel shell is highlighted.

  10. Temperature measurements with two different IR sensors in a continuous-flow microwave heated system

    Directory of Open Access Journals (Sweden)

    Jonas Rydfjord

    2013-10-01

    Full Text Available In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe, thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications.

  11. High-resolution compact shear stress sensor for direct measurement of skin friction in fluid flow

    Science.gov (United States)

    Xu, Muchen; Kim, Chang-Jin ``Cj''

    2015-11-01

    The high-resolution measurement of skin friction in complex flows has long been of great interest but also a challenge in fluid mechanics. Compared with indirect measurement methods (e.g., laser Doppler velocimetry), direct measurement methods (e.g., floating element) do not involve any analogy and assumption but tend to suffer from instrumentation challenges, such as low sensing resolution or misalignments. Recently, silicon micromachined floating plates showed good resolution and perfect alignment but were too small for general purposes and too fragile to attach other surface samples repeatedly. In this work, we report a skin friction sensor consisting of a monolithic floating plate and a high-resolution optical encoder to measure its displacement. The key for the high resolution is in the suspension beams, which are very narrow (e.g., 0.25 mm) to sense small frictions along the flow direction but thick (e.g., 5 mm) to be robust along all other directions. This compact, low profile, and complete sensor is easy to use and allows repeated attachment and detachment of surface samples. The sheer-stress sensor has been tested in water tunnel and towing tank at different flow conditions, showing high sensing resolution for skin friction measurement. Supported by National Science Foundation (NSF) (No. 1336966) and Defense Advanced Research Projects Agency (DARPA) (No. HR0011-15-2-0021).

  12. Liquid holdup measurement with double helix capacitance sensor in horizontal oil-water two-phase flow pipes

    Institute of Scientific and Technical Information of China (English)

    Lusheng Zhai; Ningde Jin; Zhongke Gao; Zhenya Wang

    2015-01-01

    This paper presents the characteristics of a double helix capacitance sensor for measurement of the liquid holdup in horizontal oil–water two-phase flow. The finite element method is used to calculate the sensitivity field of the sensor in a pipe with 20 mm inner diameter and the effect of sensor geometry on the distribution of sensitivity field is presented. Then, a horizontal oil–water two-phase flow experiment is carried out to measure the response of the double helix capacitance sensor, in which a novel method is proposed to calibrate the liquid holdup based on three pairs of paral el-wire capacitance probes. The performance of the sensor is analyzed in terms of the flow structures detected by mini-conductance array probes.

  13. A Magnetically Coupled Cryogenic Pump

    Science.gov (United States)

    Hatfield, Walter; Jumper, Kevin

    2011-01-01

    Historically, cryogenic pumps used for propellant loading at Kennedy Space Center (KSC) and other NASA Centers have a bellows mechanical seal and oil bath ball bearings, both of which can be problematic and require high maintenance. Because of the extremely low temperatures, the mechanical seals are made of special materials and design, have wearing surfaces, are subject to improper installation, and commonly are a potential leak path. The ball bearings are non-precision bearings [ABEC-1 (Annular Bearing Engineering Council)] and are lubricated using LOX compatible oil. This oil is compatible with the propellant to prevent explosions, but does not have good lubricating properties. Due to the poor lubricity, it has been a goal of the KSC cryogenics community for the last 15 years to develop a magnetically coupled pump, which would eliminate these two potential issues. A number of projects have been attempted, but none of the pumps was a success. An off-the-shelf magnetically coupled pump (typically used with corrosive fluids) was procured that has been used for hypergolic service at KSC. The KSC Cryogenics Test Lab (CTL) operated the pump in cryogenic LN2 as received to determine a baseline for modifications required. The pump bushing, bearings, and thrust rings failed, and the pump would not flow liquid (this is a typical failure mode that was experienced in the previous attempts). Using the knowledge gained over the years designing and building cryogenic pumps, the CTL determined alternative materials that would be suitable for use under the pump design conditions. The CTL procured alternative materials for the bearings (bronze, aluminum bronze, and glass filled PTFE) and machined new bearing bushings, sleeves, and thrust rings. The designed clearances among the bushings, sleeves, thrust rings, case, and case cover were altered once again using experience gained from previous cryogenic pump rebuilds and designs. The alternative material parts were assembled into

  14. Compact Mass Flow Meter Based on a Micro Coriolis Flow Sensor

    Directory of Open Access Journals (Sweden)

    Remco Wiegerink

    2013-03-01

    Full Text Available In this paper we demonstrate a compact ready-to-use micro Coriolis mass flow meter. The full scale flow is 1 g/h (for water at a pressure drop < 1 bar. It has a zero stability of 2 mg/h and an accuracy of 0.5% reading for both liquids and gases. The temperature drift between 10 and 50 °C is below 1 mg/h/°C. The meter is robust, has standard fluidic connections and can be read out by means of a PC or laptop via USB. Its performance was tested for several common gases (hydrogen, helium, nitrogen, argon and air and liquids (water and isopropanol. As in all Coriolis mass flow meters, the meter is also able to measure the actual density of the medium flowing through the tube. The sensitivity of the measured density is ~1 Hz.m3/kg.

  15. A new contactless impedance sensor for void fraction measurement of gas-liquid two-phase flow

    Science.gov (United States)

    Ji, Haifeng; Chang, Ya; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

    2016-12-01

    With impedance elimination principle and phase sensitive demodulation (PSD) technique, this work aims to develop a new contactless impedance sensor, which is suitable for the void fraction measurement of gas-liquid two-phase flow. The impedance elimination principle is used to overcome the unfavorable influences of the coupling capacitances, i.e. the capacitive reactances of the coupling capacitances are eliminated by the inductive reactance of an introduced inductor. PSD technique is used to implement the impedance measurement. Unlike the conventional conductance/impedance sensors which use the equivalent conductance (the real part of the impedance) or the amplitude of the impedance of gas-liquid two-phase flow, the new contactless impedance sensor makes full use of the total impedance information of gas-liquid two-phase flow (including the amplitude, the real part and the imaginary part of the impedance, especially the imaginary part) to implement the void fraction measurement. As a preliminary study, to verify the effectiveness of the new contactless impedance sensor, two prototypes (with different inner diameters of 17.0 mm and 22.0 mm) are developed and experiments are carried out. Two typical flow patterns (bubble flow and stratified flow) of gas-liquid two-phase flow are investigated. The experimental results show that the new contactless impedance sensor is successful and effective. Compared with the conventional conductance/impedance sensors, the new contactless impedance sensor can avoid polarization effect and electrochemical erosion effect. The total impedance information is used and the void fraction measurement performance of the new sensor is satisfactory. The experimental results also indicate that the imaginary part of the impedance of gas-liquid two-phase flow is very useful for the void fraction measurement. Making full use of the total impedance information of gas-liquid two-phase flow can effectively improve the void fraction measurement

  16. Robust Pt1000 temperature sensor for cryogenic applications in the process measurement technology; Robuste Pt1000-Temperaturfuehler fuer kryogene Anwendungen in der Prozessmesstechnik

    Energy Technology Data Exchange (ETDEWEB)

    Ramalingam, Rajini Kumar; Langhans, Oliver; Suesser, Manfred [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Inst. fuer Technische Physik (ITEP)

    2012-07-01

    The process measurement technology has a great demand for robust temperature sensors for temperatures between 20 and 500 K. The field of application is for example the hydrogen technology or the utilization of neon for the cooling of high temperature superconductors. Pt1000 temperature sensors with a shell conductor are investigated for this large range of temperatures in the calibration laboratory of the Institute for Technical Physics (Eggenstein-Leopoldshafen, Federal Republic of Germany). The Pt1000 temperature sensors were supplied by the manufacturer. The specific characteristic lines of 21 temperature sensors were determined. Furthermore, the thermal stability was investigated by means of multiple temperature cycles between 78 and 525 K. The contribution under consideration presents the investigations of this institute in detail and discusses the measurement results with regard to the industrial process measurement technology.

  17. Dynamic On-Chip micro Temperature and Flow Sensor for miniaturized lab-on-a-chip instruments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to design, fabricate, and characterize a Dynamic On-Chip Flow and Temperature Sensor (DOCFlaTS) to mature and enable miniaturized...

  18. Plasma Sensor for High Bandwidth Mass-Flow Measurements at High Mach Numbers with RF Link Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposal is aimed at the development of a miniature high bandwidth (1 MHz class) plasma sensor for flow measurements at high enthalpies. This device uses a...

  19. James Webb Space Telescope Integrated Science Instrument Module Calibration and Verification of High-Accuracy Instrumentation to Measure Heat Flow in Cryogenic Testing

    Science.gov (United States)

    Comber, Brian; Glazer, Stuart

    2012-01-01

    The James Webb Space Telescope (JWST) is an upcoming flagship observatory mission scheduled to be launched in 2018. Three of the four science instruments are passively cooled to their operational temperature range of 36K to 40K, and the fourth instrument is actively cooled to its operational temperature of approximately 6K. The requirement for multiple thermal zoned results in the instruments being thermally connected to five external radiators via individual high purity aluminum heat straps. Thermal-vacuum and thermal balance testing of the flight instruments at the Integrated Science Instrument Module (ISIM) element level will take place within a newly constructed shroud cooled by gaseous helium inside Goddard Space Flight Center's (GSFC) Space environment Simulator (SES). The flight external radiators are not available during ISIM-level thermal vacuum/thermal testing, so they will be replaced in test with stable and adjustable thermal boundaries with identical physical interfaces to the flight radiators. Those boundaries are provided by specially designed test hardware which also measures the heat flow within each of the five heat straps to an accuracy of less than 2 mW, which is less than 5% of the minimum predicted heat flow values. Measurement of the heat loads to this accuracy is essential to ISIM thermal model correlation, since thermal models are more accurately correlated when temperature data is supplemented by accurate knowledge of heat flows. It also provides direct verification by test of several high-level thermal requirements. Devices that measure heat flow in this manner have historically been referred to a "Q-meters". Perhaps the most important feature of the design of the JWST Q-meters is that it does not depend on the absolute accuracy of its temperature sensors, but rather on knowledge of precise heater power required to maintain a constant temperature difference between sensors on two stages, for which a table is empirically developed during a

  20. A cryogenic test facility

    Science.gov (United States)

    Veenendaal, Ian

    The next generation, space-borne instruments for far infrared spectroscopy will utilize large diameter, cryogenically cooled telescopes in order to achieve unprecedented sensitivities. Low background, ground-based cryogenic facilities are required for the cryogenic testing of materials, components and subsystems. The Test Facility Cryostat (TFC) at the University of Lethbridge is a large volume, closed cycle, 4K cryogenic facility, developed for this purpose. This thesis discusses the design and performance of the facility and associated external instrumentation. An apparatus for measuring the thermal properties of materials is presented, and measurements of the thermal expansion and conductivity of carbon fibre reinforced polymers (CFRPs) at cryogenic temperatures are reported. Finally, I discuss the progress towards the design and fabrication of a demonstrator cryogenic, far infrared Fourier transform spectrometer.

  1. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  2. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  3. Measurement of local two-phase flow parameters of nanofluids using conductivity double-sensor probe

    Directory of Open Access Journals (Sweden)

    Park Yu sun

    2011-01-01

    Full Text Available Abstract A two-phase flow experiment using air and water-based γ-Al2O3 nanofluid was conducted to observe the basic hydraulic phenomenon of nanofluids. The local two-phase flow parameters were measured with a conductivity double-sensor two-phase void meter. The void fraction, interfacial velocity, interfacial area concentration, and mean bubble diameter were evaluated, and all of those results using the nanofluid were compared with the corresponding results for pure water. The void fraction distribution was flattened in the nanofluid case more than it was in the pure water case. The higher interfacial area concentration resulted in a smaller mean bubble diameter in the case of the nanofluid. This was the first attempt to measure the local two-phase flow parameters of nanofluids using a conductivity double-sensor two-phase void meter. Throughout this experimental study, the differences in the internal two-phase flow structure of the nanofluid were identified. In addition, the heat transfer enhancement of the nanofluid can be resulted from the increase of the interfacial area concentration which means the available area of the heat and mass transfer.

  4. Study on the inside gas flow visualization of oxygen sensor cover; Kashika ni yoru O2 sensor cover nai no gas nagare hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Hocho, S.; Mitsuishi, Y.; Inagaki, M. [Nippon Soken, Inc., Tokyo (Japan); Hamaguchi, S.; Mizusawa, K. [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    In order to make clear the difference of the response time between the oxygen sensors with different protection covers, we visualized gas flow inside of sensor covers by means of two experimental methods: One is `Smoke Suspension Method` using liquid paraffin vapor as the smoke. With smoke suspension method, we detected the streamlines inside of the covers. The other is `Color Reaction Method` using the reaction of phenolphthalein and NH3 gas. With color reaction method, we confirmed the streamline inside of the cover and furthermore detected the difference of the response time of each sensor. 3 refs., 7 figs., 1 tab.

  5. An open-source wireless sensor stack: from Arduino to SDI-12 to Water One Flow

    Science.gov (United States)

    Hicks, S.; Damiano, S. G.; Smith, K. M.; Olexy, J.; Horsburgh, J. S.; Mayorga, E.; Aufdenkampe, A. K.

    2013-12-01

    Implementing a large-scale streaming environmental sensor network has previously been limited by the high cost of the datalogging and data communication infrastructure. The Christina River Basin Critical Zone Observatory (CRB-CZO) is overcoming the obstacles to large near-real-time data collection networks by using Arduino, an open source electronics platform, in combination with XBee ZigBee wireless radio modules. These extremely low-cost and easy-to-use open source electronics are at the heart of the new DIY movement and have provided solutions to countless projects by over half a million users worldwide. However, their use in environmental sensing is in its infancy. At present a primary limitation to widespread deployment of open-source electronics for environmental sensing is the lack of a simple, open-source software stack to manage streaming data from heterogeneous sensor networks. Here we present a functioning prototype software stack that receives sensor data over a self-meshing ZigBee wireless network from over a hundred sensors, stores the data locally and serves it on demand as a CUAHSI Water One Flow (WOF) web service. We highlight a few new, innovative components, including: (1) a versatile open data logger design based the Arduino electronics platform and ZigBee radios; (2) a software library implementing SDI-12 communication protocol between any Arduino platform and SDI12-enabled sensors without the need for additional hardware (https://github.com/StroudCenter/Arduino-SDI-12); and (3) 'midStream', a light-weight set of Python code that receives streaming sensor data, appends it with metadata on the fly by querying a relational database structured on an early version of the Observations Data Model version 2.0 (ODM2), and uses the WOFpy library to serve the data as WaterML via SOAP and REST web services.

  6. Introduction to cryogenic engineering

    CERN Document Server

    CERN. Geneva; Vandoni, Giovanna; Niinikoski, Tapio O

    2005-01-01

    Cryogenic engineering is one of the key technologies at CERN. It is widely used in research and has many applications in industry and last but not least in medicine. In research cryogenic engineering and its applications are omnipresent from the smallest laboratories to fusion reactors, hughe detectors and accelerators. With the termination of the LHC, CERN will in fact become the world's largest cryogenic installation. This series of talks intends to introduce the non-cryogenist to the basic principles and challenges of cryogenic engineering and its applications. The course will also provide a basis for practical application as well as for further learning.

  7. A novel fluorescent sensor for measurement of CFTR function by flow cytometry.

    Science.gov (United States)

    Vijftigschild, Lodewijk A W; van der Ent, Cornelis K; Beekman, Jeffrey M

    2013-06-01

    Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis. CFTR-dependent iodide transport measured by fluorescent quenching of ectopically expressed halide-sensitive yellow fluorescent protein (YFP) is widely being used to study CFTR function by microscopy or plate readers. Since YFP fluorescence in these systems is dependent on YFP expression levels and iodide concentration, differences in sensor expression level between experimental units are normalized at the start of each experiment. To allow accurate measurement of CFTR function by flow cytometry, we reasoned that co-expression of an iodide insensitive fluorescent protein would allow for normalization of sensor expression levels and more accurate quantification of CFTR function. Our data indicated that dsRed and mKate fluorescence are iodide insensitive, and we determined an optimal format for co-expression of these fluorescent proteins with halide-sensitive YFP. We showed using microscopy that ratiometric measurement (YFP/mKate) corrects for differences in sensor expression levels. Ratiometric measurements were essential to accurately measure CFTR function by flow cytometry that we here describe for the first time. Mixing of wild type or mutant CFTR expressing cells indicated that addition of approximately 10% of wild type CFTR expressing cells could be distinguished by ratiometric YFP quenching. Flow cytometric ratiometric YFP quenching also allowed us to study CFTR mutants associated with differential residual function upon ectopic expression. Compared with conventional plate-bound CFTR function assays, the flow cytometric approach described here can be used to study CFTR function in suspension cells. It may be further adapted to study CFTR function in heterologous cell populations using cell surface markers and selection of cells that display high CFTR function by cell sorting.

  8. Optical Flow in a Smart Sensor Based on Hybrid Analog-Digital Architecture

    Directory of Open Access Journals (Sweden)

    Pablo Guzmán

    2010-03-01

    Full Text Available The purpose of this study is to develop a motion sensor (delivering optical flow estimations using a platform that includes the sensor itself, focal plane processing resources, and co-processing resources on a general purpose embedded processor. All this is implemented on a single device as a SoC (System-on-a-Chip. Optical flow is the 2-D projection into the camera plane of the 3-D motion information presented at the world scenario. This motion representation is widespread well-known and applied in the science community to solve a wide variety of problems. Most applications based on motion estimation require work in real-time; hence, this restriction must be taken into account. In this paper, we show an efficient approach to estimate the motion velocity vectors with an architecture based on a focal plane processor combined on-chip with a 32 bits NIOS II processor. Our approach relies on the simplification of the original optical flow model and its efficient implementation in a platform that combines an analog (focal-plane and digital (NIOS II processor. The system is fully functional and is organized in different stages where the early processing (focal plane stage is mainly focus to pre-process the input image stream to reduce the computational cost in the post-processing (NIOS II stage. We present the employed co-design techniques and analyze this novel architecture. We evaluate the system’s performance and accuracy with respect to the different proposed approaches described in the literature. We also discuss the advantages of the proposed approach as well as the degree of efficiency which can be obtained from the focal plane processing capabilities of the system. The final outcome is a low cost smart sensor for optical flow computation with real-time performance and reduced power consumption that can be used for very diverse application domains.

  9. Optical flow in a smart sensor based on hybrid analog-digital architecture.

    Science.gov (United States)

    Guzmán, Pablo; Díaz, Javier; Agís, Rodrigo; Ros, Eduardo

    2010-01-01

    The purpose of this study is to develop a motion sensor (delivering optical flow estimations) using a platform that includes the sensor itself, focal plane processing resources, and co-processing resources on a general purpose embedded processor. All this is implemented on a single device as a SoC (System-on-a-Chip). Optical flow is the 2-D projection into the camera plane of the 3-D motion information presented at the world scenario. This motion representation is widespread well-known and applied in the science community to solve a wide variety of problems. Most applications based on motion estimation require work in real-time; hence, this restriction must be taken into account. In this paper, we show an efficient approach to estimate the motion velocity vectors with an architecture based on a focal plane processor combined on-chip with a 32 bits NIOS II processor. Our approach relies on the simplification of the original optical flow model and its efficient implementation in a platform that combines an analog (focal-plane) and digital (NIOS II) processor. The system is fully functional and is organized in different stages where the early processing (focal plane) stage is mainly focus to pre-process the input image stream to reduce the computational cost in the post-processing (NIOS II) stage. We present the employed co-design techniques and analyze this novel architecture. We evaluate the system's performance and accuracy with respect to the different proposed approaches described in the literature. We also discuss the advantages of the proposed approach as well as the degree of efficiency which can be obtained from the focal plane processing capabilities of the system. The final outcome is a low cost smart sensor for optical flow computation with real-time performance and reduced power consumption that can be used for very diverse application domains.

  10. Flow Cytometry Enables Multiplexed Measurements of Genetically Encoded Intramolecular FRET Sensors Suitable for Screening.

    Science.gov (United States)

    Doucette, Jaimee; Zhao, Ziyan; Geyer, Rory J; Barra, Melanie M; Balunas, Marcy J; Zweifach, Adam

    2016-07-01

    Genetically encoded sensors based on intramolecular FRET between CFP and YFP are used extensively in cell biology research. Flow cytometry has been shown to offer a means to measure CFP-YFP FRET; we suspected it would provide a unique way to conduct multiplexed measurements from cells expressing different FRET sensors, which is difficult to do with microscopy, and that this could be used for screening. We confirmed that flow cytometry accurately measures FRET signals using cells transiently transfected with an ERK activity reporter, comparing responses measured with imaging and cytometry. We created polyclonal long-term transfectant lines, each expressing a different intramolecular FRET sensor, and devised a way to bar-code four distinct populations of cells. We demonstrated the feasibility of multiplexed measurements and determined that robust multiplexed measurements can be conducted in plate format. To validate the suitability of the method for screening, we measured responses from a plate of bacterial extracts that in unrelated experiments we had determined contained the protein kinase C (PKC)-activating compound teleocidin A-1. The multiplexed assay correctly identifying the teleocidin A-1-containing well. We propose that multiplexed cytometric FRET measurements will be useful for analyzing cellular function and for screening compound collections.

  11. Spatial Copula Model for Imputing Traffic Flow Data from Remote Microwave Sensors.

    Science.gov (United States)

    Ma, Xiaolei; Luan, Sen; Du, Bowen; Yu, Bin

    2017-09-21

    Issues of missing data have become increasingly serious with the rapid increase in usage of traffic sensors. Analyses of the Beijing ring expressway have showed that up to 50% of microwave sensors pose missing values. The imputation of missing traffic data must be urgently solved although a precise solution that cannot be easily achieved due to the significant number of missing portions. In this study, copula-based models are proposed for the spatial interpolation of traffic flow from remote traffic microwave sensors. Most existing interpolation methods only rely on covariance functions to depict spatial correlation and are unsuitable for coping with anomalies due to Gaussian consumption. Copula theory overcomes this issue and provides a connection between the correlation function and the marginal distribution function of traffic flow. To validate copula-based models, a comparison with three kriging methods is conducted. Results indicate that copula-based models outperform kriging methods, especially on roads with irregular traffic patterns. Copula-based models demonstrate significant potential to impute missing data in large-scale transportation networks.

  12. Wind energy harvesting and self-powered flow rate sensor enabled by contact electrification

    Science.gov (United States)

    Su, Yuanjie; Xie, Guangzhong; Xie, Tao; Zhang, Hulin; Ye, Zongbiao; Jing, Qingshen; Tai, Huiling; Du, Xiaosong; Jiang, Yadong

    2016-06-01

    We have developed a free-standing-mode based triboelectric nanogenerator (F-TENG) that consists of indium tin oxide (ITO) foils and a polytetrafluoroethylene (PTFE) thin film. By utilizing the wind-induced resonance vibration of a PTFE film between two ITO electrodes, the F-TENG delivers an open-circuit voltage up to 37 V and a short-circuit current of 6.2 μA, which can be used as a sustainable power source to simultaneously and continuously light up tens of light emitting diodes (LEDs) and charge capacitors. Moreover, uniform division of the electrode into several parallel units efficiently suppresses the inner counteracting effect of undulating film and leads to an enhancement of output current by 95%. The F-TENG holds prominent durability and an excellent linear relationship between output current and flow rate, revealing its feasibility as a self-powered sensor for detecting wind speed. This work demonstrates potential applications of the triboelectric generator in gas flow harvesters, self-powered air navigation, self-powered gas sensors and wind vector sensors.

  13. Unsaturated and Saturated Flow Front Tracking in Liquid Composite Molding Processes using Dielectric Sensors

    Science.gov (United States)

    Carlone, P.; Palazzo, G. S.

    2015-10-01

    Liquid composite molding processes are manufacturing techniques involving the impregnation and saturation of dry fibrous preforms by means of injection or infusion of catalyzed resin systems. Complete wetting of the reinforcement and reduction of voids are key issues to enhance mechanical properties of the final product, as a consequence on line monitoring and control of resin flow is highly desirable to detect and avoid potentialbet macro- as well as micro-voids. In this paper, parallel-plate dielectric sensors were investigated to track the position of unsaturated as well as saturated flow fronts through dual scale porous media. Sensors configuration was analyzed and improved via electromagnetic (EM) finite element simulations. The effectiveness of the proposed system was assessed in one-dimensional impregnation tests. Good agreement was found between unsaturated front positions provided by the considered system and acquired through conventional visual techniques. An indirect verification strategy, based on CFD and EM simulations of the process, was applied to investigate the reliability of dielectric sensors with respect to saturation phenomena. Obtained outcomes highlighted the intriguing capabilities of the proposed method.

  14. Design of a Sensor Based on Plastic Optical Fibre (POF) to Measure Fluid Flow and Turbidity.

    Science.gov (United States)

    Aiestaran, Pedro; Arrue, Jon; Zubia, Joseba

    2009-01-01

    Although many optical fibre applications are based on their capacity to transmit optical signals with low losses, it can also be desirable for the optical fibre to be strongly affected by a certain physical parameter in the environment. In this way, it can be used as a sensor for this parameter. There are many strong arguments for the use of POFs as sensors. In addition to being easy to handle and low cost, they demonstrate advantages common to all multimode optical fibres. These specifically include flexibility, small size, good electromagnetic compatibility behaviour, and in general, the possibility of measuring any phenomenon without physically interacting with it. In this paper, a sensor based on POF is designed and analysed with the aim of measuring the volume and turbidity of a low viscosity fluid, in this case water, as it passes through a pipe. A comparative study with a commercial sensor is provided to validate the proven flow measurement. Likewise, turbidity is measured using different colour dyes. Finally, this paper will present the most significant results and conclusions from all the tests which are carried out.

  15. Design of a Sensor Based on Plastic Optical Fibre (POF to Measure Fluid Flow and Turbidity

    Directory of Open Access Journals (Sweden)

    Joseba Zubia

    2009-05-01

    Full Text Available Although many optical fibre applications are based on their capacity to transmit optical signals with low losses, it can also be desirable for the optical fibre to be strongly affected by a certain physical parameter in the environment. In this way, it can be used as a sensor for this parameter. There are many strong arguments for the use of POFs as sensors. In addition to being easy to handle and low cost, they demonstrate advantages common to all multimode optical fibres. These specifically include flexibility, small size, good electromagnetic compatibility behaviour, and in general, the possibility of measuring any phenomenon without physically interacting with it. In this paper, a sensor based on POF is designed and analysed with the aim of measuring the volume and turbidity of a low viscosity fluid, in this case water, as it passes through a pipe. A comparative study with a commercial sensor is provided to validate the proven flow measurement. Likewise, turbidity is measured using different colour dyes. Finally, this paper will present the most significant results and conclusions from all the tests which are carried out.

  16. Flight Performance of the AKARI Cryogenic System

    CERN Document Server

    Nakagawa, Takao; Hirabayashi, Masayuki; Kaneda, Hidehiro; Kii, Tsuneo; Kimura, Yoshiyuki; Matsumoto, Toshio; Murakami, Hiroshi; Murakami, Masahide; Narasaki, Katsuhiro; Narita, Masanao; Ohnishi, Akira; Tsunematsu, Shoji; Yoshida, Seiji

    2007-01-01

    We describe the flight performance of the cryogenic system of the infrared astronomical satellite AKARI, which was successfully launched on 2006 February 21 (UT). AKARI carries a 68.5 cm telescope together with two focal plane instruments, Infrared Cameras (IRC) and Far Infrared Surveyor (FIS), all of which are cooled down to cryogenic temperature to achieve superior sensitivity. The AKARI cryogenic system is a unique hybrid system, which consists of cryogen (liquid helium) and mechanical coolers (2-stage Stirling coolers). With the help of the mechanical coolers, 179 L (26.0 kg) of super-fluid liquid helium can keep the instruments cryogenically cooled for more than 500 days. The on-orbit performance of the AKARI cryogenics is consistent with the design and pre-flight test, and the boil-off gas flow rate is as small as 0.32 mg/s. We observed the increase of the major axis of the AKARI orbit, which can be explained by the thrust due to thermal pressure of vented helium gas.

  17. Aircraft Aerodynamic Parameter Detection Using Micro Hot-Film Flow Sensor Array and BP Neural Network Identification

    Science.gov (United States)

    Que, Ruiyi; Zhu, Rong

    2012-01-01

    Air speed, angle of sideslip and angle of attack are fundamental aerodynamic parameters for controlling most aircraft. For small aircraft for which conventional detecting devices are too bulky and heavy to be utilized, a novel and practical methodology by which the aerodynamic parameters are inferred using a micro hot-film flow sensor array mounted on the surface of the wing is proposed. A back-propagation neural network is used to model the coupling relationship between readings of the sensor array and aerodynamic parameters. Two different sensor arrangements are tested in wind tunnel experiments and dependence of the system performance on the sensor arrangement is analyzed. PMID:23112638

  18. The Development of a Gas-Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus.

    Science.gov (United States)

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-11-18

    The measurement of wellbore annulus gas-liquid two-phase flow in CBM (coalbed methane) wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas-liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work.

  19. A Generic Framework for Enabling the Flow of Sensor Observations to Archives: O2A

    Science.gov (United States)

    Gerchow, Peter; Koppe, Roland; Macario, Ana; Haas, Antonie; Shäfer-Neth, Christian

    2015-04-01

    Over the last two decades, the Alfred Wegener Institute (AWI) has been continuously committing to develop and sustain an e-Infrastructure for coherent discovery, visualization, dissemination and archival of scientific information in polar and marine regions. Most of the data originates from research activities being carried out in a wide range of AWI-operated research platforms: vessels, land-based stations, ocean-based stations and aircrafts. Archival and publishing in PANGAEA repository along with DOI assignment to individual datasets is a typical end-of-line step for most data owners. Within AWI, a workflow for data acquisition from vessel-mounted devices along with ingestion procedures for the raw data into the institutional archives has been well-established for many years. However, the increasing number of ocean-based stations and respective sensors along with heterogeneous project-driven requirements towards satellite communication, sensor monitoring, QA/QC control and validation, processing algorithms, visualization and dissemination has recently lead us to build a more generic and cost-effective framework. This framework, hereafter named O2A, has as main strength its seamless flow of sensor observation to archives and the fact that it complies with internationally used OGC standards and thus assuring interoperability in international context (e.g. SOS/SWE, WPS, WMS WFS,..). O2A is comprised of several extensible and exchangeable modules (e.g. controlled vocabularies and gazetteers, file type and structure validation, aggregation solutions, processing algorithms, etc) as well as various interoperability services. At the first data tier level, not only each sensor is being described following SensorML data model standards but the data is being fed to an SOS interface offering streaming solutions along with support to O&M encoding. Project administrators or data specialists are now able to monitor the individual sensors displayed in a map by simply clicking

  20. Mass flow-rate control unit to calibrate hot-wire sensors

    Energy Technology Data Exchange (ETDEWEB)

    Durst, F.; Uensal, B. [FMP Technology GmbH, Erlangen (Germany); Haddad, K. [FMP Technology GmbH, Erlangen (Germany); Friedrich-Alexander-Universitaet Erlangen-Nuernberg, LSTM-Erlangen, Institute of Fluid Mechanics, Erlangen (Germany); Al-Salaymeh, A.; Eid, Shadi [University of Jordan, Mechanical Engineering Department, Faculty of Engineering and Technology, Amman (Jordan)

    2008-02-15

    Hot-wire anemometry is a measuring technique that is widely employed in fluid mechanics research to study the velocity fields of gas flows. It is general practice to calibrate hot-wire sensors against velocity. Calibrations are usually carried out under atmospheric pressure conditions and these suggest that the wire is sensitive to the instantaneous local volume flow rate. It is pointed out, however, that hot wires are sensitive to the instantaneous local mass flow rate and, of course, also to the gas heat conductivity. To calibrate hot wires with respect to mass flow rates per unit area, i.e., with respect to ({rho}U), requires special calibration test rigs. Such a device is described and its application is summarized within the ({rho}U) range 0.1-25 kg/m{sup 2} s. Calibrations are shown to yield the same hot-wire response curves for density variations in the range 1-7 kg/m{sup 3}. The application of the calibrated wires to measure pulsating mass flows is demonstrated, and suggestions are made for carrying out extensive calibrations to yield the ({rho}U) wire response as a basis for advanced fluid mechanics research on ({rho}U) data in density-varying flows. (orig.)

  1. Characterization of a Low-Cost Optical Flow Sensor When Using an External Laser as a Direct Illumination Source

    Directory of Open Access Journals (Sweden)

    Jordi Palacín

    2011-12-01

    Full Text Available In this paper, a low cost optical flow sensor is combined with an external laser device to measure surface displacements and mechanical oscillations. The measurement system is based on applying coherent light to a diffuser surface and using an optical flow sensor to analyze the reflected and transferred light to estimate the displacement of the surface or the laser spot. This work is focused on the characterization of this measurement system, which can have the optical flow sensor placed at different angles and distances from the diffuser surface. The results have shown that the displacement of the diffuser surface is badly estimated when the optical mouse sensor is placed in front of the diffuser surface (angular orientation >150° while the highest sensitivity is obtained when the sensor is located behind the diffuser surface and on the axis of the laser source (angular orientation 0°. In this case, the coefficient of determination of the measured displacement, R2, was very high (>0.99 with a relative error of less than 1.29%. Increasing the distance between the surface and the sensor also increased the sensitivity which increases linearly, R2 = 0.99. Finally, this measurement setup was proposed to measure very low frequency mechanical oscillations applied to the laser device, up to 0.01 Hz in this work. The results have shown that increasing the distance between the surface and the optical flow sensor also increases the sensitivity and the measurement range.

  2. Ceramic hot film sensor for exhaust gas mass flow measurements in automotive applications; Keramischer Heissfilmsensor zur Abgasmassenstrommessung in automotiven Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Dismon, Heinrich; Grimm, Karsten; Toennesmann, Andres; Nigrin, Sven [Pierburg GmbH, Neuss (Germany); Wienand, Karlheinz; Muziol, Matthias [Heraeus Sensor Technology GmbH, Kleinostheim (Germany)

    2008-07-01

    Due to increasingly stringent emission standards, a number of internal measures as well as exhaust gas aftertreatment systems have become state-of-the-art technology for passenger car and heavy duty engines. However, the full potential of these measures, for example the cooled external exhaust gas recirculation, can only be utilized if the engine control is adapted adequately well in all engine states. Thus, the requirements for future engine controls become more demanding and consequently the standards for sensors used in the control loop will increase. In this context this article introduces a new exhaust gas mass flow sensor based or the principle of hot film anemometry. The sensor comprising a ceramic sensor element is developed especially for the use in engine exhaust gases providing the exhaust gas mass flow as a direct measurement and control variable. Next to the sensor technology first results of engine tests are presented in this paper. (orig.)

  3. Development and characterization of a calorimetric flow sensor realized in thick-film technology; Aufbau und Charakterisierung eines kalorimetrischen Stroemungssensors in Dickschichttechnik

    Energy Technology Data Exchange (ETDEWEB)

    Smetana, W.; Unger, M.; Gschohsmann, W. [Technische Univ. Wien (Austria). Inst. fuer Sensor- und Aktuatorsysteme

    2006-10-15

    Based on the results of Finite Element Analyses a calorimetric flow-sensor has been realized on a steel tube by thick-film technology. The sensor characteristics have been determined experimentally as well as by numerical simulation. The paper discusses procedures required to increase the linearity range of the sensor characteristic and sensor signal output. (orig.)

  4. Flow-less and shape-conformable CNT sheet nanogenerator for self-powered motion sensor.

    Science.gov (United States)

    Song, Hyelynn; Kim, Taewoo; Im, Hyeongwook; Ovalle-Robles, Raquel; Kang, Tae June; Kim, Yong Hyup

    2016-09-22

    A carbon nanotube (CNT) sheet nanogenerator that does not require any liquid or gas flow for power generation is developed on the basis of Coulombic interactions, making the device attractive as a building block for self-powered sensors. The working principle of the CNT nanogenerator is probed in terms of sweeping speed, distance between charged object and nanotube sheet, surface charge, and number of layers of nanotube sheet. The nature of the CNT sheet and its formation process is such that simply winding the CNT sheet stripe n times around a substrate leads to increasing the power n times. For a practical demonstration of the CNT nanogenerator, a self-powered sensor array screen is developed that can read finger movements, just as with a finger command on a smartphone screen.

  5. Rainfall measurement based on in-situ storm drainage flow sensors

    DEFF Research Database (Denmark)

    Ahm, Malte; Rasmussen, Michael Robdrup

    2017-01-01

    these sensors, it may be possible to improve the ground rainfall estimate, and thereby improve the quantitative precipitation estimation from weather radars for urban drainage applications. To test the hypothesis, this paper presents a rainfall measurement method based on flow rate measurements from well......Data for adjustment of weather radar rainfall estimations are mostly obtained from rain gauge observations. However, the density of rain gauges is often very low. Yet in many urban catchments, runoff sensors are typically available which can measure the rainfall indirectly. By utilising......-defined urban surfaces. This principle was used to design a runoff measurement system in a parking structure in Aalborg, Denmark, where it was evaluated against rain gauges. The measurements show that runoff measurements from well-defined urban surfaces perform just as well as rain gauges. This opens up...

  6. Modeling of Potential Distribution of Electrical Capacitance Tomography Sensor for Multiphase Flow Image

    Directory of Open Access Journals (Sweden)

    S. Sathiyamoorthy

    2007-09-01

    Full Text Available Electrical Capacitance Tomography (ECT was used to develop image of various multi phase flow of gas-liquid-solid in a closed pipe. The principal difficulties to obtained real time image from ECT sensor are permittivity distribution across the plate and capacitance is nonlinear; the electric field is distorted by the material present and is also sensitive to measurement errors and noise. This work present a detailed description is given on method employed for image reconstruction from the capacitance measurements. The discretization and iterative algorithm is developed for improving the predictions with minimum error. The author analyzed eight electrodes square sensor ECT system with two-phase water-gas and solid-gas.

  7. Modeling, fabrication and plasma actuator coupling of flexible pressure sensors for flow separation detection and control in aeronautical applications

    Science.gov (United States)

    Francioso, L.; De Pascali, C.; Pescini, E.; De Giorgi, M. G.; Siciliano, P.

    2016-06-01

    Preventing the flow separation could enhance the performance of propulsion systems and future civil aircraft. To this end, a fast detection of boundary layer separation is mandatory for a sustainable and successful application of active flow control devices, such as plasma actuators. The present work reports on the design, fabrication and functional tests of low-cost capacitive pressure sensors coupled with dielectric barrier discharge (DBD) plasma actuators to detect and then control flow separation. Finite element method (FEM) simulations were used to obtain information on the deflection and the stress distribution in different-shaped floating membranes. The sensor sensitivity as a function of the pressure load was also calculated by experimental tests. The results of the calibration of different capacitive pressure sensors are reported in this work, together with functional tests in a wind tunnel equipped with a curved wall plate on which a DBD plasma actuator was mounted to control the flow separation. The flow behavior was experimentally investigated by particle image velocimetry (PIV) measurements. Statistical and spectral analysis, applied to the output signals of the pressure sensor placed downstream of the profile leading edge, demonstrated that the sensor is able to discriminate different ionic wind velocity and turbulence conditions. The sensor sensitivity in the 0-100 Pa range was experimentally measured and it ranged between 0.0030 and 0.0046 pF Pa-1 for the best devices.

  8. MEMS Flow Sensors Based on Self-Heated aGe-Thermistors in a Wheatstone Bridge.

    Science.gov (United States)

    Talic, Almir; Cerimovic, Samir; Beigelbeck, Roman; Kohl, Franz; Sauter, Thilo; Keplinger, Franz

    2015-04-28

    A thermal flow transduction method combining the advantages of calorimetric and hot-film transduction principles is developed and analyzed by Finite Element Method (FEM) simulations and confirmed experimentally. The analyses include electrothermal feedback effects of current driven NTC thermistors. Four thin-film germanium thermistors acting simultaneously as heat sources and as temperature sensors are embedded in a micromachined silicon-nitride membrane. These devices form a self-heated Wheatstone bridge that is unbalanced by convective cooling. The voltage across the bridge and the total dissipated power are exploited as output quantities. The used thin-film thermistors feature an extremely high temperature sensitivity. Combined with properly designed resistance values, a power demand in sub-1mW range enables efficient gas-flow transduction, as confirmed by measurements. Two sensor configurations with different arrangements of the membrane thermistors were examined experimentally. Moreover, we investigated the influence of different layouts on the rise time, the sensitivity, and the usable flow range by means of two-dimensional finite element simulations. The simulation results are in reasonable agreement with corresponding measurement data confirming the basic assumptions and modeling approach.

  9. Satellite Testbed for Evaluating Cryogenic-Liquid Behavior in Microgravity

    Science.gov (United States)

    Putman, Philip Travis (Inventor)

    2017-01-01

    Provided is a testbed for conducting an experiment on a substance in a cryogenic liquid state in a microgravity environment. The testbed includes a frame with rectangular nominal dimensions, and a source section including a supply of the substance to be evaluated in the cryogenic liquid state. An experiment section includes an experiment vessel in fluid communication with the storage section to receive the substance from the storage section and condense the substance into the cryogenic liquid state. A sensor is adapted to sense a property of the substance in the cryogenic liquid state in the experiment vessel as part of the experiment. A bus section includes a controller configured to control delivery of the substance from the storage section to the experiment vessel, and receive property data indicative of the property sensed by the sensor for subsequent evaluation on Earth.

  10. The cryogenic storage ring project

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Robert von; Blaum, Klaus; Becker, Arno; Fellenberger, Florian; George, Sebastian; Grieser, Manfred; Grussie, Florian; Herwig, Philipp; Krantz, Claude; Kreckel, Holger; Lange, Michael; Menk, Sebastian; Repnow, Roland; Vogel, Stephen; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Spruck, Kaija [Justus-Liebig-Universitaet, Giessen (Germany)

    2014-07-01

    At MPIK the electrostatic cryogenic storage ring CSR is nearing completion. At beam energies of 20 to 300 keV per charge unit and 35 m circumference the CSR will allow experiments in a cryogenic environment providing conditions of extremely low vacuum and heat radiation. By using liquid helium at 2 K for cryopumping, the projected vacuum (confirmed at a prototype) lies at 1E-13 mbar or below, ensuring long storage times for slow singly charged and highly charged ions, molecules and clusters. Moreover, phase space cooling by electrons will be implemented. The internal quantum states of molecular and cluster ions can be cooled to low temperature, yielding well defined vibrational and for smaller systems also rotational structures. In the CSR construction, the cryogenic ion beam vacuum system has been set up. Extensive tests confirming the criteria on heat flow, alignment and high-voltage stability were successfully completed on the first quadrant. In addition beam diagnostic units for electric pickup signals and spatial profiles, detectors for neutral and charged fragments, the injection beam line, and an electron cooling device are under construction.

  11. Negative-Resistance Characteristics Analysis of Poly-Silicon Resistors Formed on the Flow Sensor

    Institute of Scientific and Technical Information of China (English)

    Dianzhong Wen

    2006-01-01

    In this paper we put forward a new concept about effective trapping center concentration NeT which is decreasing with the trapped charge Q corresponding to index movement, based on that, we discuss the I-V and temperature characteristics of polysilicon resistors. The new concept presents ideal theoretical interpretion for the originally observed current-voltage negative-resistance characteristics of polysilicon resistors formed on the flow sensor, and also for poly-silicon film resistors.The final results agree well with the theoretical current-voltage characteristics.

  12. 液位传感器校准装置几何误差模型及不确定度评定%Geometric Error Model and Uncertainty Evaluation on Calibration Device of Cryogenic Liquid Level Sensor

    Institute of Scientific and Technical Information of China (English)

    于航; 李东升; 王梅宝; 马豪; 张晓丹; 王颖

    2016-01-01

    立足于接触式低温液位传感器的校准需求,设计并研制了液位传感器动态校准装置,以实现在常温及低温条件下对测量范围为1800 mm、极限误差为±2 mm的电容式传感器的校准。采用齐次坐标变换原理,从导轨直线度误差、定位误差、各连结链空间角度误差、液面波动误差等方面入手,建立了低温液位传感器校准装置的几何误差模型。对低温液位传感器校准装置的测量不确定度进行了评定,结果表明:扩展不确定度为U=0.53 mm ( k=2),满足低温液位传感器的校准精度要求。%Based on the need of calibrating the liquid level sensor , dynamic calibration device was designed and developed for liquid level sensor which applied to capacitive sensors ( measuring range is 1 800 mm, and limiting error is ±2 mm) in both normal and low temperature conditions .The principle of homogeneous coordinate transformation was used to establish geometric error model for the calibration device , which mainly contained the rail straightness error , positioning error , spatial angle error of each chain and level fluc-tuation error, and other aspects.Moreover, the uncertainty of calibration device was evaluated .The results show that the expanded un-certainty is U=0.53 mm ( k=2) , which meets the specifications of calibration accuracy of the cryogenic liquid level sensor .

  13. Design of fan beam optical sensor and its application in mass flow rate measurement of pneumatically conveyed solids

    Institute of Scientific and Technical Information of China (English)

    LI Yang; ZHENG Ying-na; YUE Hong-wei

    2005-01-01

    The fan-beam optical sensor is made up of many semiconductor lasers and detectors fixed around the wall alternately at a cross section of pneumatically conveying pipe. When the sensor works, a scanning light source emits a 50° lamellar fan-beam through the gas-solid two phase flow, and the projection data resulting extinction effect of solid particles are detected at the same time. With the projection data, the flow rate mass can be calculated, and then the flow image can be reconstructed. In this paper, the design of the sensor including spatial arrangement of the structural parts, basic principle and measurement sensitivity distribution are introduced. The mathematical measurement model of solid mass flow rate is presented together with the testing results.

  14. Fiber-optic flow sensors for high-temperature environment operation up to 800°C.

    Science.gov (United States)

    Chen, Rongzhang; Yan, Aidong; Wang, Qingqing; Chen, Kevin P

    2014-07-01

    This Letter presents an all-optical high-temperature flow sensor based on hot-wire anemometry. High-attenuation fibers (HAFs) were used as the heating elements. High-temperature-stable regenerated fiber Bragg gratings were inscribed in HAFs and in standard telecom fibers as temperature sensors. Using in-fiber light as both the heating power source and the interrogation light source, regenerative fiber Bragg grating sensors were used to gauge the heat transfer from an optically powered heating element induced by the gas flow. Reliable gas flow measurements were demonstrated between 0.066  m/s and 0.66  m/s from the room temperature to 800°C. This Letter presents a compact, low-cost, and multiflexible approach to measure gas flow for high-temperature harsh environments.

  15. From Biological Cilia to Artificial Flow Sensors: Biomimetic Soft Polymer Nanosensors with High Sensing Performance

    Science.gov (United States)

    Asadnia, Mohsen; Kottapalli, Ajay Giri Prakash; Karavitaki, K. Domenica; Warkiani, Majid Ebrahimi; Miao, Jianmin; Corey, David P.; Triantafyllou, Michael

    2016-09-01

    We report the development of a new class of miniature all-polymer flow sensors that closely mimic the intricate morphology of the mechanosensory ciliary bundles in biological hair cells. An artificial ciliary bundle is achieved by fabricating bundled polydimethylsiloxane (PDMS) micro-pillars with graded heights and electrospinning polyvinylidenefluoride (PVDF) piezoelectric nanofiber tip links. The piezoelectric nature of a single nanofiber tip link is confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Rheology and nanoindentation experiments are used to ensure that the viscous properties of the hyaluronic acid (HA)-based hydrogel are close to the biological cupula. A dome-shaped HA hydrogel cupula that encapsulates the artificial hair cell bundle is formed through precision drop-casting and swelling processes. Fluid drag force actuates the hydrogel cupula and deflects the micro-pillar bundle, stretching the nanofibers and generating electric charges. Functioning with principles analogous to the hair bundles, the sensors achieve a sensitivity and threshold detection limit of 300 mV/(m/s) and 8 μm/s, respectively. These self-powered, sensitive, flexible, biocompatibale and miniaturized sensors can find extensive applications in navigation and maneuvering of underwater robots, artificial hearing systems, biomedical and microfluidic devices.

  16. Drag Reduction of Turbulence Air Channel Flow with Distributed Micro Sensors and Actuators

    Science.gov (United States)

    Yoshino, Takashi; Suzuki, Yuji; Kasagi, Nobuhide

    A prototype system for feedback control of wall turbulence is developed, and its performance is evaluated in a physical experiment. Arrayed micro hot-film sensors with a spanwise spacing of 1 mm are employed for the measurement of streamwise shear stress fluctuations, while arrayed magnetic actuators of 2.4 mm in spanwise width are used to introduce control input through wall deformation. A digital signal processor with a time delay of 0.1 ms is employed to drive the actuators based on the sensor signals. The driving voltage of each actuator is determined with a linear combination of the wall shear stress fluctuations at three sensors located upstream of the actuator, and a noise-tolerant genetic algorithm is employed to optimize the control parameters. Feedback control experiments are conducted in a fully-developed turbulent air channel flow at the Reynolds number of Reτ=300. It is found that about 6% drag reduction has been achieved in a physical experiment for the first time. Through turbulent statistics measurements with LDV, it is also found that the Reynolds shear stress close to the wall is decreased by the present control scheme. A conditional average of a DNS database is also made to extract coherent structures associated with the present control input. It is shown that the wall-deformation actuators induce a wall-normal velocity away from the wall when the high-speed region is located above the actuator.

  17. Afocal Optical Flow Sensor for Reducing Vertical Height Sensitivity in Indoor Robot Localization and Navigation

    Directory of Open Access Journals (Sweden)

    Dong-Hoon Yi

    2015-05-01

    Full Text Available This paper introduces a novel afocal optical flow sensor (OFS system for odometry estimation in indoor robotic navigation. The OFS used in computer optical mouse has been adopted for mobile robots because it is not affected by wheel slippage. Vertical height variance is thought to be a dominant factor in systematic error when estimating moving distances in mobile robots driving on uneven surfaces. We propose an approach to mitigate this error by using an afocal (infinite effective focal length system. We conducted experiments in a linear guide on carpet and three other materials with varying sensor heights from 30 to 50 mm and a moving distance of 80 cm. The same experiments were repeated 10 times. For the proposed afocal OFS module, a 1 mm change in sensor height induces a 0.1% systematic error; for comparison, the error for a conventional fixed-focal-length OFS module is 14.7%. Finally, the proposed afocal OFS module was installed on a mobile robot and tested 10 times on a carpet for distances of 1 m. The average distance estimation error and standard deviation are 0.02% and 17.6%, respectively, whereas those for a conventional OFS module are 4.09% and 25.7%, respectively.

  18. Afocal optical flow sensor for reducing vertical height sensitivity in indoor robot localization and navigation.

    Science.gov (United States)

    Yi, Dong-Hoon; Lee, Tae-Jae; Cho, Dong-Il Dan

    2015-05-13

    This paper introduces a novel afocal optical flow sensor (OFS) system for odometry estimation in indoor robotic navigation. The OFS used in computer optical mouse has been adopted for mobile robots because it is not affected by wheel slippage. Vertical height variance is thought to be a dominant factor in systematic error when estimating moving distances in mobile robots driving on uneven surfaces. We propose an approach to mitigate this error by using an afocal (infinite effective focal length) system. We conducted experiments in a linear guide on carpet and three other materials with varying sensor heights from 30 to 50 mm and a moving distance of 80 cm. The same experiments were repeated 10 times. For the proposed afocal OFS module, a 1 mm change in sensor height induces a 0.1% systematic error; for comparison, the error for a conventional fixed-focal-length OFS module is 14.7%. Finally, the proposed afocal OFS module was installed on a mobile robot and tested 10 times on a carpet for distances of 1 m. The average distance estimation error and standard deviation are 0.02% and 17.6%, respectively, whereas those for a conventional OFS module are 4.09% and 25.7%, respectively.

  19. From Biological Cilia to Artificial Flow Sensors: Biomimetic Soft Polymer Nanosensors with High Sensing Performance.

    Science.gov (United States)

    Asadnia, Mohsen; Kottapalli, Ajay Giri Prakash; Karavitaki, K Domenica; Warkiani, Majid Ebrahimi; Miao, Jianmin; Corey, David P; Triantafyllou, Michael

    2016-09-13

    We report the development of a new class of miniature all-polymer flow sensors that closely mimic the intricate morphology of the mechanosensory ciliary bundles in biological hair cells. An artificial ciliary bundle is achieved by fabricating bundled polydimethylsiloxane (PDMS) micro-pillars with graded heights and electrospinning polyvinylidenefluoride (PVDF) piezoelectric nanofiber tip links. The piezoelectric nature of a single nanofiber tip link is confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Rheology and nanoindentation experiments are used to ensure that the viscous properties of the hyaluronic acid (HA)-based hydrogel are close to the biological cupula. A dome-shaped HA hydrogel cupula that encapsulates the artificial hair cell bundle is formed through precision drop-casting and swelling processes. Fluid drag force actuates the hydrogel cupula and deflects the micro-pillar bundle, stretching the nanofibers and generating electric charges. Functioning with principles analogous to the hair bundles, the sensors achieve a sensitivity and threshold detection limit of 300 mV/(m/s) and 8 μm/s, respectively. These self-powered, sensitive, flexible, biocompatibale and miniaturized sensors can find extensive applications in navigation and maneuvering of underwater robots, artificial hearing systems, biomedical and microfluidic devices.

  20. Simulations of Cavitating Cryogenic Inducers

    Science.gov (United States)

    Dorney, Dan (Technical Monitor); Hosangadi, Ashvin; Ahuja, Vineet; Ungewitter, Ronald J.

    2004-01-01

    Simulations of cavitating turbopump inducers at their design flow rate are presented. Results over a broad range of Nss, numbers extending from single-phase flow conditions through the critical head break down point are discussed. The flow characteristics and performance of a subscale geometry designed for water testing are compared with the fullscale configuration that employs LOX. In particular, thermal depression effects arising from cavitation in cryogenic fluids are identified and their impact on the suction performance of the inducer quantified. The simulations have been performed using the CRUNCH CFD[R] code that has a generalized multi-element unstructured framework suitable for turbomachinery applications. An advanced multi-phase formulation for cryogenic fluids that models temperature depression and real fluid property variations is employed. The formulation has been extensively validated for both liquid nitrogen and liquid hydrogen by simulating the experiments of Hord on hydrofoils; excellent estimates of the leading edge temperature and pressure depression were obtained while the comparisons in the cavity closure region were reasonable.

  1. Traffic Flow Condition Classification for Short Sections Using Single Microwave Sensor

    Science.gov (United States)

    Cinsdikici, Muhammed G.; Memiş, Kemal

    2010-12-01

    Daily observed traffic flow can show different characteristics varying with the times of the day. They are caused by traffic incidents such as accidents, disabled cars, construction activities and other unusual events. Three different major traffic conditions can be occurred: "Flow," "Dense" and "Congested". Objective of this research is to identify the current traffic condition by examining the traffic measurement parameters. The earlier researches have dealt only with speed and volume by ignoring occupancy. In our study, the occupancy is another important parameter of classification. The previous works have used multiple sensors to classify traffic condition whereas our work uses only single microwave sensor. We have extended Multiple Linear Regression classification with our new approach of Estimating with Error Prediction. We present novel algorithms of Multiclassification with One-Against-All Method and Multiclassification with Binary Comparison for multiple SVM architecture. Finaly, a non-linear model of backpropagation neural network is introduced for classification. This combination has not been reported on previous studies. Training data are obtained from the Corsim based microscopic traffic simulator TSIS 5.1. All performances are compared using this data set. Our methods are currently installed and running at traffic management center of 2.Ring Road in Istanbul.

  2. An Autonomous UAV with an Optical Flow Sensor for Positioning and Navigation

    Directory of Open Access Journals (Sweden)

    Nils Gageik

    2013-10-01

    Full Text Available A procedure to control all six DOF (degrees of freedom of a UAV (unmanned aerial vehicle without an external reference system and to enable fully autonomous flight is presented here. For 2D positioning the principle of optical flow is used. Together with the output of height estimation, fusing ultrasonic, infrared and inertial and pressure sensor data, the 3D position of the UAV can be computed, controlled and steered. All data processing is done on the UAV. An external computer with a pathway planning interface is for commanding purposes only. The presented system is part of the AQopterI8 project, which aims to develop an autonomous flying quadrocopter for indoor application. The focus of this paper is 2D positioning using an optical flow sensor. As a result of the performed evaluation, it can be concluded that for position hold, the standard deviation of the position error is 10cm and after landing the position error is about 30cm.

  3. Traffic Flow Condition Classification for Short Sections Using Single Microwave Sensor

    Directory of Open Access Journals (Sweden)

    Memiş Kemal

    2010-01-01

    Full Text Available Daily observed traffic flow can show different characteristics varying with the times of the day. They are caused by traffic incidents such as accidents, disabled cars, construction activities and other unusual events. Three different major traffic conditions can be occurred: "Flow," "Dense" and "Congested". Objective of this research is to identify the current traffic condition by examining the traffic measurement parameters. The earlier researches have dealt only with speed and volume by ignoring occupancy. In our study, the occupancy is another important parameter of classification. The previous works have used multiple sensors to classify traffic condition whereas our work uses only single microwave sensor. We have extended Multiple Linear Regression classification with our new approach of Estimating with Error Prediction. We present novel algorithms of Multiclassification with One-Against-All Method and Multiclassification with Binary Comparison for multiple SVM architecture. Finaly, a non-linear model of backpropagation neural network is introduced for classification. This combination has not been reported on previous studies. Training data are obtained from the Corsim based microscopic traffic simulator TSIS 5.1. All performances are compared using this data set. Our methods are currently installed and running at traffic management center of 2.Ring Road in Istanbul.

  4. A new sensor for stress measurement based on blood flow fluctuations

    Science.gov (United States)

    Fine, I.; Kaminsky, A. V.; Shenkman, L.

    2016-03-01

    It is widely recognized that effective stress management could have a dramatic impact on health care and preventive medicine. In order to meet this need, efficient and seamless sensing and analytic tools for the non-invasive stress monitoring during daily life are required. The existing sensors still do not meet the needs in terms of specificity and robustness. We utilized a miniaturized dynamic light scattering sensor (mDLS) which is specially adjusted to measure skin blood flow fluctuations and provides multi- parametric capabilities. Based on the measured dynamic light scattering signal from the red blood cells flowing in skin, a new concept of hemodynamic indexes (HI) and oscillatory hemodynamic indexes (OHI) have been developed. This approach was utilized for stress level assessment for a few usecase scenario. The new stress index was generated through the HI and OHI parameters. In order to validate this new non-invasive stress index, a group of 19 healthy volunteers was studied by measuring the mDLS sensor located on the wrist. Mental stress was induced by using the cognitive dissonance test of Stroop. We found that OHIs indexes have high sensitivity to the mental stress response for most of the tested subjects. In addition, we examined the capability of using this new stress index for the individual monitoring of the diurnal stress level. We found that the new stress index exhibits similar trends as reported for to the well-known diurnal behavior of cortisol levels. Finally, we demonstrated that this new marker provides good sensitivity and specificity to the stress response to sound and musical emotional arousal.

  5. Long-Period Fiber Grating Sensors for the Measurement of Liquid Level and Fluid-Flow Velocity

    Directory of Open Access Journals (Sweden)

    Jian-Neng Wang

    2012-04-01

    Full Text Available This paper presents the development and assessment of two types of Long Period Fiber Grating (LPFG-based sensors including a mobile liquid level sensor and a reflective sensor for the measurement of liquid level and fluid-flow velocity. Shewhart control charts were used to assess the liquid level sensing capacity and reliability of the mobile CO2-laser engraved LPFG sensor. There were ten groups of different liquid level experiment and each group underwent ten repeated wavelength shift measurements. The results showed that all measurands were within the control limits; thus, this mobile sensor was reliable and exhibited at least 100-cm liquid level measurement capacity. In addition, a reflective sensor consisting of five LPFGs in series with a reflective end has been developed to evaluate the liquid level and fluid-flow velocity. These five LPFGs were fabricated by the electrical arc discharge method and the reflective end was coated with silver by Tollen’s test. After each liquid level experiment was performed five times, the average values of the resonance wavelength shifts for LPFG Nos. 1–5 were in the range of 1.35–9.14 nm. The experimental findings showed that the reflective sensor could be used to automatically monitor five fixed liquid levels. This reflective sensor also exhibited at least 100-cm liquid level measurement capacity. The mechanism of the fluid-flow velocity sensor was based on analyzing the relationship among the optical power, time, and the LPFG’s length. There were two types of fluid-flow velocity measurements: inflow and drainage processes. The differences between the LPFG-based fluid-flow velocities and the measured average fluid-flow velocities were found in the range of 8.7–12.6%. For the first time to our knowledge, we have demonstrated the feasibility of liquid level and fluid-flow velocity sensing with a reflective LPFG-based sensor without modifying LPFGs or coating chemical compounds.

  6. Ultrasonic torsional guided wave sensor for flow front monitoring inside molds.

    Science.gov (United States)

    Visvanathan, Karthik; Balasubramaniam, Krishnan

    2007-01-01

    Measuring the extent of flow of viscous fluids inside opaque molds has been a very important parameter in determining the quality of products in the manufacturing process such as injection molding and resin transfer molding. Hence, in this article, an ultrasonic torsional guided wave sensor has been discussed for monitoring the movement of flow front during filling of resins in opaque molds. A pair of piezoelectric normal shear transducers were used for generating and receiving the fundamental ultrasonic torsional guided wave mode in thin copper wires. The torsional mode was excited at one end of the wire, while the flowing viscous fluid progressively wet the other free end of the wire. The time of flight of the transient reflections of this fundamental mode from the air-fluid interface, where the wire enters the resin, was used to measure the position of the fluid flow front. Experiments were conducted on four fluids with different viscosity values. Two postprocessing algorithms were developed for enhancing the transient reflected signal and for suppressing the unwanted stationary signals. The algorithms were tested for cases where the reflected signals showed a poor signal to noise ratio.

  7. Polymers at cryogenic temperatures

    CERN Document Server

    Fu, Shao-Yun

    2013-01-01

    Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.

  8. SNS Cryogenic Systems Commissioning

    Science.gov (United States)

    Hatfield, D.; Casagrande, F.; Campisi, I.; Gurd, P.; Howell, M.; Stout, D.; Strong, H.; Arenius, D.; Creel, J.; Dixon, K.; Ganni, V.; Knudsen, P.

    2006-04-01

    The Spallation Neutron Source (SNS) is under construction at Oak Ridge National Laboratory. The cold section of the Linac consists of 81 superconducting radio frequency cavities cooled to 2.1K by a 2400 watt cryogenic refrigeration system. The major cryogenic system components include warm helium compressors with associated oil removal and gas management, 4.5K cold box, 7000L liquid helium dewar, 2.1K cold box (consisting of 4 stages of cold compressors), gaseous helium storage, helium purification and gas impurity monitoring system, liquid nitrogen storage and the cryogenic distribution transfer line system. The overall system commissioning and future plans will be presented.

  9. FRIB Cryogenic Plant Status

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Kelly D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ganni, Venkatarao [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Knudsen, Peter N. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Casagranda, Fabio [Michigan State Univ., East Lansing, MI (United States)

    2015-12-01

    After practical changes were approved to the initial conceptual design of the cryogenic system for MSU FRIB and an agreement was made with JLab in 2012 to lead the design effort of the cryogenic plant, many activities are in place leading toward a cool-down of the linacs prior to 2018. This is mostly due to using similar equipment used at CHLII for the 12 GeV upgrade at JLab and an aggressive schedule maintained by the MSU Conventional Facilities department. Reported here is an updated status of the cryogenic plant, including the equipment procurement status, plant layout, facility equipment and project schedule.

  10. SNS Cryogenic Systems Commissioning

    Energy Technology Data Exchange (ETDEWEB)

    D. Hatfield; F. Casagrande; I. Campisi; P. Gurd; M. Howell; D. Stout; H. Strong; D. Arenius; J. Creel; K. Dixon; V. Ganni; and P. Knudsen

    2005-08-29

    The Spallation Neutron Source (SNS) is under construction at Oak Ridge National Laboratory. The cold section of the Linac consists of 81 superconducting radio frequency cavities cooled to 2.1K by a 2400 watt cryogenic refrigeration system. The major cryogenic system components include warm helium compressors with associated oil removal and gas management, 4.5K cold box, 7000L liquid helium dewar, 2.1K cold box (consisting of 4 stages of cold compressors), gaseous helium storage, helium purification and gas impurity monitoring system, liquid nitrogen storage and the cryogenic distribution transfer line system. The overall system commissioning and future plans will be presented.

  11. Fundamentals of cryogenic engineering

    CERN Document Server

    Mukhopadhyay, Mamata

    2014-01-01

    The author, with her vast and varied experience in teaching and allied fields, clearly enunciates the behaviour and various properties of common cryogenic fluids, methods of liquefaction, and separation and applications of cryogens with thermodynamic analysis for process selection. This profusely illustrated study with clear-cut diagrams and process charts, should serve not only as a textbook for students but also as an excellent reference for researchers and practising engineers on design of cryogenic refrigeration, and liquefaction and separation process plants for various applications.

  12. Influence of Thermal Cycling on Cryogenic Thermometers

    CERN Document Server

    Balle, C; Rieubland, Jean Michel; Suraci, A; Togny, F; Vauthier, N

    1999-01-01

    The stringent requirements on temperature control of the superconducting magnets for the Large Hadron Collider (LHC), impose that the cryogenic temperature sensors meet compelling demands such as long-term stability, radiation hardness, readout accuracy better than 5 mK at 1.8 K and compatibility with industrial control equipment. This paper presents the results concerning long-term stability of resistance temperature sensors submitted to cryogenic thermal cycles. For this task a simple test facility has been designed, constructed and put into operation for cycling simultaneously 115 cryogenic thermometers between 300 K and 4.2 K. A thermal cycle is set to last 71/4 hours: 3 hours for either cooling down or warming up the sensors and 1 respectively 1/4 hour at steady temperature conditions at each end of the temperature cycle. A Programmable Logic Controller (PLC) drives automatically this operation by reading 2 thermometers and actuating on 3 valves and 1 heater. The first thermal cycle was accomplished in a...

  13. Cryogenics for LHC experiments

    CERN Multimedia

    2001-01-01

    Cryogenic systems will be used by LHC experiments to maximize their performance. Institutes around the world are collaborating with CERN in the construction of these very low temperature systems. The cryogenic test facility in hall 180 for ATLAS magnets. High Energy Physics experiments have frequently adopted cryogenic versions of their apparatus to achieve optimal performance, and those for the LHC will be no exception. The two largest experiments for CERN's new flagship accelerator, ATLAS and CMS, will both use large superconducting magnets operated at 4.5 Kelvin - almost 270 degrees below the freezing point of water. ATLAS also includes calorimeters filled with liquid argon at 87 Kelvin. For the magnets, the choice of a cryogenic version was dictated by a combination economy and transparency to emerging particles. For the calorimeters, liquid argon was selected as the fluid best suited to the experiment's physics requirements. High Energy Physics experiments are the result of worldwide collaborations and...

  14. Advances in Cryogenic Principles

    Science.gov (United States)

    Barron, R. F.

    During the past 50 years, the use of digital computers has significantly influenced the design and analysis of cryogenic systems. At the time when the first Cryogenic Engineering Conference was held, thermodynamic data were presented in graphical or tabular form (the "steam table" format), whereas thermodynamic data for cryogenic system design is computer generated today. The thermal analysis of cryogenic systems in the 1950s involved analytical solutions, graphical solutions, and relatively simple finite-difference approaches. These approaches have been supplanted by finite-element numerical programs which readily solve complicated thermal problems that could not be solved easily using the methods of the 1950s. In distillation column design, the use of the McCabe-Thiele graphical method for determination of the number of theoretical plates has been replaced by numerical methods that allow consideration of several different components in the feed and product streams.

  15. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique

    Science.gov (United States)

    Battista, L.; Sciuto, S. A.; Scorza, A.

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10-4 m3/s (18.0 l/min) for the mono-directional sensor and a measurement range of ±3.00 × 10-4 m3/s (±18.0 l/min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the

  16. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique.

    Science.gov (United States)

    Battista, L; Sciuto, S A; Scorza, A

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10(-4) m(3)∕s (18.0 l∕min) for the mono-directional sensor and a measurement range of ±3.00 × 10(-4) m(3)∕s (±18.0 l∕min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono

  17. Design details of Intelligent Instruments for PLC-free Cryogenic measurements, control and data acquisition

    Science.gov (United States)

    Antony, Joby; Mathuria, D. S.; Chaudhary, Anup; Datta, T. S.; Maity, T.

    2017-02-01

    Cryogenic network for linear accelerator operations demand a large number of Cryogenic sensors, associated instruments and other control-instrumentation to measure, monitor and control different cryogenic parameters remotely. Here we describe an alternate approach of six types of newly designed integrated intelligent cryogenic instruments called device-servers which has the complete circuitry for various sensor-front-end analog instrumentation and the common digital back-end http-server built together, to make crateless PLC-free model of controls and data acquisition. These identified instruments each sensor-specific viz. LHe server, LN2 Server, Control output server, Pressure server, Vacuum server and Temperature server are completely deployed over LAN for the cryogenic operations of IUAC linac (Inter University Accelerator Centre linear Accelerator), New Delhi. This indigenous design gives certain salient features like global connectivity, low cost due to crateless model, easy signal processing due to integrated design, less cabling and device-interconnectivity etc.

  18. Water Pipeline Monitoring and Leak Detection using Flow Liquid Meter Sensor

    Science.gov (United States)

    Rahmat, R. F.; Satria, I. S.; Siregar, B.; Budiarto, R.

    2017-04-01

    Water distribution is generally installed through underground pipes. Monitoring the underground water pipelines is more difficult than monitoring the water pipelines located on the ground in open space. This situation will cause a permanent loss if there is a disturbance in the pipeline such as leakage. Leaks in pipes can be caused by several factors, such as the pipe’s age, improper installation, and natural disasters. Therefore, a solution is required to detect and to determine the location of the damage when there is a leak. The detection of the leak location will use fluid mechanics and kinematics physics based on harness water flow rate data obtained using flow liquid meter sensor and Arduino UNO as a microcontroller. The results show that the proposed method is able to work stably to determine the location of the leak which has a maximum distance of 2 metres, and it’s able to determine the leak location as close as possible with flow rate about 10 litters per minute.

  19. The dependence of Nusselt number on Reynolds number for a hot-wire sensor in supercritical CO2 flow

    Science.gov (United States)

    Vukoslavcevic, Petar; Wallace, James

    2005-11-01

    An analysis of the heat transfer mechanism around a hot-wire sensor in superctitical CO2 flow has been performed, and the dependence of the Nusselt number (Nu) on the Reynolds number (Re) has been determined. A special, closed flow loop, capable of inducing variable speed flow at different pressures and temperatures in the ranges of 0.15-2 m/s, 15-70^oC and 1-100 bar, has been used to create a supercritical CO2 flow around a hot-wire sensor operated in the constant temperature mode. The Nu and Re numbers were determined based on the known heat convected from the sensor, the flow speed and the sensor temperature and dimensions. The experiment was performed along a line of constant 80 bar pressure in the temperature range of 25-65^oC. It was found that, at a given pressure and temperature, the relation Nu=F(Re) has the classical form Nu=M+NRe^n, with the parameters M and N being functions of pressure and temperature. The dependence of these parameters on temperature was analyzed, and the most convenient reference temperature was chosen. In contrast to the operation of hot-wires in air and water, the dependence of the parameters M and N on the Prandtl number can result in nonunique solutions.

  20. Damage evaluation based on a wave energy flow map using multiple PZT sensors.

    Science.gov (United States)

    Liu, Yaolu; Hu, Ning; Xu, Hong; Yuan, Weifeng; Yan, Cheng; Li, Yuan; Goda, Riu; Alamusi, Emptyyn Y; Qiu, Jinhao; Ning, Huiming; Wu, Liangke

    2014-01-23

    A new wave energy flow (WEF) map concept was proposed in this work. Based on it, an improved technique incorporating the laser scanning method and Betti's reciprocal theorem was developed to evaluate the shape and size of damage as well as to realize visualization of wave propagation. In this technique, a simple signal processing algorithm was proposed to construct the WEF map when waves propagate through an inspection region, and multiple lead zirconate titanate (PZT) sensors were employed to improve inspection reliability. Various damages in aluminum and carbon fiber reinforced plastic laminated plates were experimentally and numerically evaluated to validate this technique. The results show that it can effectively evaluate the shape and size of damage from wave field variations around the damage in the WEF map.

  1. Simultaneous measurements of multiple flow parameters for scramjet characterization using tunable diode-laser sensors.

    Science.gov (United States)

    Li, Fei; Yu, Xilong; Gu, Hongbin; Li, Zhi; Zhao, Yan; Ma, Lin; Chen, Lihong; Chang, Xinyu

    2011-12-20

    This paper reports the simultaneous measurements of multiple flow parameters in a scramjet facility operating at a nominal Mach number of 2.5 using a sensing system based on tunable diode-laser absorption spectroscopy (TDLAS). The TDLAS system measures velocity, temperature, and water vapor partial pressure at three different locations of the scramjet: the inlet, the combustion region near the flame stabilization cavity, and the exit of the combustor. These measurements enable the determination of the variation of the Mach number and the combustion mode in the scramjet engine, which are critical for evaluating the combustion efficiency and optimizing engine performance. The results obtained in this work clearly demonstrated the applicability of TDLAS sensors in harsh and high-speed environments. The TDLAS system, due to its unique virtues, is expected to play an important role in the development of scramjet engines.

  2. 一种用于低流量测量的浮子流量传感器%A Float Flow Sensor for Low Flow Measurement

    Institute of Scientific and Technical Information of China (English)

    于宝; 孔垂广; 于靖民

    2012-01-01

    针对目前广泛存在的日产量小于10m3的油井及目前所应用的涡轮流量计测量下限较高和易砂卡等问题,根据流体力学相关原理,建立适合低流量测量的理论模型,分析其中的影响因素,采用独特设计技术,研制出外径为28 mm的浮子流量传感器.通过实验,确立油井流量在0~20m3/d变化范围内,所研制的浮子流量传感器的测量频率响应与被测液体流量之间为线性关系.在模拟仿真系统所能提供的水流量下限(0.24m3/d)和油流量下限(0.05m3/d)情况下,传感器仍有较高频率输出响应,表明所研制的浮子流量传感器适合低产液油井流量测量.%At present, the production of oil wells is less than 10 m3/d, and the turbine flowmeter often provides non-accurate log responses and results in sanding-in problem, etc. According to the fluid mechanics principle, established are theory models for the low flow measurement, and analyzed are influence factors on the models. Developed is a unique float flow sensor with 28 mm diameter. Through a series of experiments, established are linear relationships between the measurement frequency response of the sensor and the measured liquid flow when flow variation range of the oil wells is 0~20 m3/d. Estimated is lower flow limit of float flow sensor, the result of which shows that even when the lower water flow limit is 0. 24 m3/d and lower oil flow limit is 0.05 m3/d, the sensor also has higher frequency output response, which indicates that the float flow sensor developed is suitable for lower yield oil wells flow measurement.

  3. Evaluation of a gravel transport sensor for bed load measurements in natural flows

    Institute of Scientific and Technical Information of China (English)

    Athanasios N.(Thanos) PAPANICOLAOU; Mohamed ELHAKEEM; Doug KNAPP

    2009-01-01

    A recent acoustic instrument (Gravel Transport Sensor,GTS) was tested for predicting sediment transport rate (bed load rate) in gravel bed streams.The GTS operation is based on the particle collision theory of submerged obstacles in fluids.When particles collide with the GTS cylinder their momentum is recorded in the form of ping rates.The GTS is attractive for further consideration here because of its potential to provide continuous unattended local bed load measurements,especially in areas found in streams that access may be difficult under extreme conditions.Laboratory experiments coupled with numerical simulations for the same flow conditions were performed in order to determine the conditions under which particles of different size will hit the GTS cylinder and be able to register a ping rate.The GTS was able to detect the number of particles with diameter in the range of 15.9 to 25.4 mm,with reasonable accuracy,if the applied Shields effective stress τ*e =τ*-τ*cr was in the range of 0.006 to 0.015.A drawback of the tested prototype GTS,however,was that it exerted increased resistance on the incoming particles.The added drag effects increased the overall resistance that was exerted by the flow on particles and thus increased the likelihood that particles will rest in the ambient region of the cylinder instead of hitting it.Numerical simulation of the flow around the GTS cylinder revealed that changing the prototype geometry from cylindrical to ellipsoid or rhomboid will increase the likelihood of the particles hitting the instrumet under the same flow conditions failed by the original tested GTS cylinder.

  4. Characterizing the correlations between local phase fractions of gas-liquid two-phase flow with wire-mesh sensor.

    Science.gov (United States)

    Tan, C; Liu, W L; Dong, F

    2016-06-28

    Understanding of flow patterns and their transitions is significant to uncover the flow mechanics of two-phase flow. The local phase distribution and its fluctuations contain rich information regarding the flow structures. A wire-mesh sensor (WMS) was used to study the local phase fluctuations of horizontal gas-liquid two-phase flow, which was verified through comparing the reconstructed three-dimensional flow structure with photographs taken during the experiments. Each crossing point of the WMS is treated as a node, so the measurement on each node is the phase fraction in this local area. An undirected and unweighted flow pattern network was established based on connections that are formed by cross-correlating the time series of each node under different flow patterns. The structure of the flow pattern network reveals the relationship of the phase fluctuations at each node during flow pattern transition, which is then quantified by introducing the topological index of the complex network. The proposed analysis method using the WMS not only provides three-dimensional visualizations of the gas-liquid two-phase flow, but is also a thorough analysis for the structure of flow patterns and the characteristics of flow pattern transition. This article is part of the themed issue 'Supersensing through industrial process tomography'.

  5. Application of x-ray sensors for in-line and non-invasive monitoring of mass flow rate in continuous tablet manufacturing.

    Science.gov (United States)

    Ganesh, Sudarshan; Troscinski, Rachel; Schmall, Nicholas; Lim, Jongmook; Nagy, Zoltan; Reklaitis, Gintaras

    2017-08-31

    The progress in continuous downstream manufacturing of oral solid doses demands effective real-time process management, with monitoring at its core. This study evaluates the feasibility of using a commercial sensor to measure the mass flow rate of the particulates, a critical process variable in continuous manufacturing. The sensor independently measures x-ray attenuation and cross-correlation velocimetry of particulate flow in real-time. Steady-state flow rates of blends comprised primarily of acetaminophen and microcrystalline-cellulose are monitored using the sensor, with simultaneous weighing scale measurements, in order to calibrate the sensor and investigate the measurement accuracy. The free-fall flow measurement of the powder and granule blends in a conduit is linearly proportional to the x-ray attenuation. Relative standard deviations (RSD) of ∼3-7% for 1 second monitoring are observed and a measurement error of approximately 5% suggest the usability of the sensor for real-time monitoring. The sensor measurement is robust for operational variations in composition, addition of lubricant or glidant and reuse of material for PAT tool calibration. The measurement RSD depends on particulate flow dynamics at the sensor location. This requires experimental evaluation for a given material at the sensor location, in order to capture the flow dynamics of the particulate stream through the sensor. Copyright © 2017. Published by Elsevier Inc.

  6. An innovative design for cardiopulmonary resuscitation manikins based on a human-like thorax and embedded flow sensors.

    Science.gov (United States)

    Thielen, Mark; Joshi, Rohan; Delbressine, Frank; Bambang Oetomo, Sidarto; Feijs, Loe

    2017-03-01

    Cardiopulmonary resuscitation manikins are used for training personnel in performing cardiopulmonary resuscitation. State-of-the-art cardiopulmonary resuscitation manikins are still anatomically and physiologically low-fidelity designs. The aim of this research was to design a manikin that offers high anatomical and physiological fidelity and has a cardiac and respiratory system along with integrated flow sensors to monitor cardiac output and air displacement in response to cardiopulmonary resuscitation. This manikin was designed in accordance with anatomical dimensions using a polyoxymethylene rib cage connected to a vertebral column from an anatomical female model. The respiratory system was composed of silicon-coated memory foam mimicking lungs, a polyvinylchloride bronchus and a latex trachea. The cardiovascular system was composed of two sets of latex tubing representing the pulmonary and aortic arteries which were connected to latex balloons mimicking the ventricles and lumped abdominal volumes, respectively. These balloons were filled with Life/form simulation blood and placed inside polyether foam. The respiratory and cardiovascular systems were equipped with flow sensors to gather data in response to chest compressions. Three non-medical professionals performed chest compressions on this manikin yielding data corresponding to force-displacement while the flow sensors provided feedback. The force-displacement tests on this manikin show a desirable nonlinear behaviour mimicking chest compressions during cardiopulmonary resuscitation in humans. In addition, the flow sensors provide valuable data on the internal effects of cardiopulmonary resuscitation. In conclusion, scientifically designed and anatomically high-fidelity designs of cardiopulmonary resuscitation manikins that embed flow sensors can improve physiological fidelity and provide useful feedback data.

  7. Using a magnetite/thermoplastic composite in 3D printing of direct replacements for commercially available flow sensors

    Science.gov (United States)

    Leigh, S. J.; Purssell, C. P.; Billson, D. R.; Hutchins, D. A.

    2014-09-01

    Flow sensing is an essential technique required for a wide range of application environments ranging from liquid dispensing to utility monitoring. A number of different methodologies and deployment strategies have been devised to cover the diverse range of potential application areas. The ability to easily create new bespoke sensors for new applications is therefore of natural interest. Fused deposition modelling is a 3D printing technology based upon the fabrication of 3D structures in a layer-by-layer fashion using extruded strands of molten thermoplastic. The technology was developed in the late 1980s but has only recently come to more wide-scale attention outside of specialist applications and rapid prototyping due to the advent of low-cost 3D printing platforms such as the RepRap. Due to the relatively low-cost of the printers and feedstock materials, these printers are ideal candidates for wide-scale installation as localized manufacturing platforms to quickly produce replacement parts when components fail. One of the current limitations with the technology is the availability of functional printing materials to facilitate production of complex functional 3D objects and devices beyond mere concept prototypes. This paper presents the formulation of a simple magnetite nanoparticle-loaded thermoplastic composite and its incorporation into a 3D printed flow-sensor in order to mimic the function of a commercially available flow-sensing device. Using the multi-material printing capability of the 3D printer allows a much smaller amount of functional material to be used in comparison to the commercial flow sensor by only placing the material where it is specifically required. Analysis of the printed sensor also revealed a much more linear response to increasing flow rate of water showing that 3D printed devices have the potential to at least perform as well as a conventionally produced sensor.

  8. An innovative design for cardiopulmonary resuscitation manikins based on a human-like thorax and embedded flow sensors

    Science.gov (United States)

    Thielen, Mark; Joshi, Rohan; Delbressine, Frank; Bambang Oetomo, Sidarto; Feijs, Loe

    2017-01-01

    Cardiopulmonary resuscitation manikins are used for training personnel in performing cardiopulmonary resuscitation. State-of-the-art cardiopulmonary resuscitation manikins are still anatomically and physiologically low-fidelity designs. The aim of this research was to design a manikin that offers high anatomical and physiological fidelity and has a cardiac and respiratory system along with integrated flow sensors to monitor cardiac output and air displacement in response to cardiopulmonary resuscitation. This manikin was designed in accordance with anatomical dimensions using a polyoxymethylene rib cage connected to a vertebral column from an anatomical female model. The respiratory system was composed of silicon-coated memory foam mimicking lungs, a polyvinylchloride bronchus and a latex trachea. The cardiovascular system was composed of two sets of latex tubing representing the pulmonary and aortic arteries which were connected to latex balloons mimicking the ventricles and lumped abdominal volumes, respectively. These balloons were filled with Life/form simulation blood and placed inside polyether foam. The respiratory and cardiovascular systems were equipped with flow sensors to gather data in response to chest compressions. Three non-medical professionals performed chest compressions on this manikin yielding data corresponding to force–displacement while the flow sensors provided feedback. The force–displacement tests on this manikin show a desirable nonlinear behaviour mimicking chest compressions during cardiopulmonary resuscitation in humans. In addition, the flow sensors provide valuable data on the internal effects of cardiopulmonary resuscitation. In conclusion, scientifically designed and anatomically high-fidelity designs of cardiopulmonary resuscitation manikins that embed flow sensors can improve physiological fidelity and provide useful feedback data. PMID:28290239

  9. Methane Liquid Level Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Technologies Group, Inc. proposes the development of a Methane Liquid-Level Sensor, (MLS) for In-Space cryogenic storage capable of continuous monitoring of...

  10. Evaluation of Stirling cooler system for cryogenic CO2 capture

    OpenAIRE

    Song, Chun Feng; Kitamura, Yutaka; Li, Shu Hong

    2012-01-01

    In previous research, a cryogenic system based on Stirling coolers has been developed. In this work, the novel system was applied on CO2 capture from post-combustion flue gas and different process parameters (i.e. flow rate of feed gas, temperature of Stirling cooler and operating condition) were investigated to obtain the optimal performance (CO2 recovery and energy consumption). From the extensive experiments, it was concluded that the cryogenic system could realize CO2 capture without solv...

  11. A fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot cavity

    Science.gov (United States)

    Liu, Guigen; Sheng, Qiwen; Resende Lisboa Piassetta, Geraldo; Hou, Weilin; Han, Ming

    2016-05-01

    A hot-wire fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot interferometer (FPI) has been proposed and demonstrated in this paper. The operation of the sensor is based on the convective heat loss to water from a heated silicon FPI attached to the cleaved enface of a piece of single-mode fiber. The flow-induced change in the temperature is demodulated by the spectral shifts of the reflection fringes. An analytical model based on the FPI theory and heat transfer analysis has been developed for performance analysis. Numerical simulations based on finite element analysis have been conducted. The analytical and numerical results agree with each other in predicting the behavior of the sensor. Experiments have also been carried to demonstrate the sensing principle and verify the theoretical analysis. Investigations suggest that the sensitivity at low flow rates are much larger than that at high flow rates and the sensitivity can be easily improved by increasing the heating laser power. Experimental results show that an average sensitivity of 52.4 nm/(m/s) for the flow speed range of 1.5 mm/s to 12 mm/s was obtained with a heating power of ~12 mW, suggesting a resolution of ~1 μm/s assuming a wavelength resolution of 0.05 pm.

  12. Cryogenic regenerative heat exchangers

    CERN Document Server

    Ackermann, Robert A

    1997-01-01

    An in-depth survey of regenerative heat exchangers, this book chronicles the development and recent commercialization of regenerative devices for cryogenic applications. Chapters cover historical background, concepts, practical applications, design data, and numerical solutions, providing the latest information for engineers to develop advanced cryogenic machines. The discussions include insights into the operation of a regenerator; descriptions of the cyclic and fluid temperature distributions in a regenerator; data for various matrix geometries and materials, including coarse and fine bronze, stainless steel-woven wire mesh screens, and lead spheres; and unique operating features of cryocoolers that produce deviations from ideal regenerator theory.

  13. A time-of-flight flow sensor for the volume measurement of trace amount of interstitial fluid

    Science.gov (United States)

    Yu, H.; Li, D.; Roberts, R. C.; Xu, K.; Tien, N. C.

    2012-05-01

    Transdermal extraction of interstitial fluid (ISF) offers an attractive method for noninvasive blood glucose monitoring. The existing macroscale systems are not suitable for ISF collection, mainly because of the minute volume of the transdermally extracted ISF which scatters on the skin surface. Human skin's low permeability to glucose and its varying permeability exemplify the crucial need to make precise ISF volume measurements in order to calculate blood glucose concentrations accurately. In this paper, we present a novel time-of-flight flow sensor consisting of four electrode pairs fabricated directly into the channel of a polydimethylsiloxane (PDMS) microfluidic device designed to accurately measure the volume of transdermally extracted ISF. As fluid traverses the channel, it bridges each electrode pair and changes its resistance. By measuring the time difference in resistance change between each electrode pair, a precise fluid volume can be measured. In order to verify the suitability of the sensor for biological applications, experiments were conducted using a normal saline solution which is similar to ISF. The stability of the sensor was tested using a fixed volume, and the coefficient of variation for 20 tests was determined to be 0.0041. The consistency of the sensor for varied volume measurements was shown by the high correlation coefficient (R2 = 0.9992) between the tested volume and the volume measured by a commercial micro syringe. The excellent functionality of the flow sensor can be extended toward the measurement of conductive chemical and biochemical buffers and reagents.

  14. Traffic Vehicle Counting in Jam Flow Conditions Using Low-Cost and Energy-Efficient Wireless Magnetic Sensors

    Directory of Open Access Journals (Sweden)

    Xu Bao

    2016-11-01

    Full Text Available The jam flow condition is one of the main traffic states in traffic flow theory and the most difficult state for sectional traffic information acquisition. Since traffic information acquisition is the basis for the application of an intelligent transportation system, research on traffic vehicle counting methods for the jam flow conditions has been worthwhile. A low-cost and energy-efficient type of multi-function wireless traffic magnetic sensor was designed and developed. Several advantages of the traffic magnetic sensor are that it is suitable for large-scale deployment and time-sustainable detection for traffic information acquisition. Based on the traffic magnetic sensor, a basic vehicle detection algorithm (DWVDA with less computational complexity was introduced for vehicle counting in low traffic volume conditions. To improve the detection performance in jam flow conditions with a “tailgating effect” between front vehicles and rear vehicles, an improved vehicle detection algorithm (SA-DWVDA was proposed and applied in field traffic environments. By deploying traffic magnetic sensor nodes in field traffic scenarios, two field experiments were conducted to test and verify the DWVDA and the SA-DWVDA algorithms. The experimental results have shown that both DWVDA and the SA-DWVDA algorithms yield a satisfactory performance in low traffic volume conditions (scenario I and both of their mean absolute percent errors are less than 1% in this scenario. However, for jam flow conditions with heavy traffic volumes (scenario II, the SA-DWVDA was proven to achieve better results, and the mean absolute percent error of the SA-DWVDA is 2.54% with corresponding results of the DWVDA 7.07%. The results conclude that the proposed SA-DWVDA can implement efficient and accurate vehicle detection in jam flow conditions and can be employed in field traffic environments.

  15. Traffic Vehicle Counting in Jam Flow Conditions Using Low-Cost and Energy-Efficient Wireless Magnetic Sensors.

    Science.gov (United States)

    Bao, Xu; Li, Haijian; Xu, Dongwei; Jia, Limin; Ran, Bin; Rong, Jian

    2016-11-06

    The jam flow condition is one of the main traffic states in traffic flow theory and the most difficult state for sectional traffic information acquisition. Since traffic information acquisition is the basis for the application of an intelligent transportation system, research on traffic vehicle counting methods for the jam flow conditions has been worthwhile. A low-cost and energy-efficient type of multi-function wireless traffic magnetic sensor was designed and developed. Several advantages of the traffic magnetic sensor are that it is suitable for large-scale deployment and time-sustainable detection for traffic information acquisition. Based on the traffic magnetic sensor, a basic vehicle detection algorithm (DWVDA) with less computational complexity was introduced for vehicle counting in low traffic volume conditions. To improve the detection performance in jam flow conditions with a "tailgating effect" between front vehicles and rear vehicles, an improved vehicle detection algorithm (SA-DWVDA) was proposed and applied in field traffic environments. By deploying traffic magnetic sensor nodes in field traffic scenarios, two field experiments were conducted to test and verify the DWVDA and the SA-DWVDA algorithms. The experimental results have shown that both DWVDA and the SA-DWVDA algorithms yield a satisfactory performance in low traffic volume conditions (scenario I) and both of their mean absolute percent errors are less than 1% in this scenario. However, for jam flow conditions with heavy traffic volumes (scenario II), the SA-DWVDA was proven to achieve better results, and the mean absolute percent error of the SA-DWVDA is 2.54% with corresponding results of the DWVDA 7.07%. The results conclude that the proposed SA-DWVDA can implement efficient and accurate vehicle detection in jam flow conditions and can be employed in field traffic environments.

  16. Two-phase flow pattern measurements with a wire mesh sensor in a direct steam generating solar thermal collector

    Science.gov (United States)

    Berger, Michael; Mokhtar, Marwan; Zahler, Christian; Willert, Daniel; Neuhäuser, Anton; Schleicher, Eckhard

    2017-06-01

    At Industrial Solar's test facility in Freiburg (Germany), two phase flow patterns have been measured by using a wire mesh sensor from Helmholtz Zentrum Dresden-Rossendorf (HZDR). Main purpose of the measurements was to compare observed two-phase flow patterns with expected flow patterns from models. The two-phase flow pattern is important for the design of direct steam generating solar collectors. Vibrations should be avoided in the peripheral piping, and local dry-outs or large circumferential temperature gradients should be prevented in the absorber tubes. Therefore, the choice of design for operation conditions like mass flow and steam quality are an important step in the engineering process of such a project. Results of a measurement with the wire mesh sensor are the flow pattern and the plug or slug frequency at the given operating conditions. Under the assumption of the collector power, which can be assumed from previous measurements at the same collector and adaption with sun position and incidence angle modifier, also the slip can be evaluated for a wire mesh sensor measurement. Measurements have been performed at different mass flows and pressure levels. Transient behavior has been tested for flashing, change of mass flow, and sudden changes of irradiation (cloud simulation). This paper describes the measurements and the method of evaluation. Results are shown as extruded profiles in top view and in side view. Measurement and model are compared. The tests have been performed at low steam quality, because of the limits of the test facility. Conclusions and implications for possible future measurements at larger collectors are also presented in this paper.

  17. 低温透平膨胀机内平衡凝结两相流动的数值模拟%Numerical Simulation of Equilibrium Condensation Two-Phase Flow in Cryogenic Turboexpander

    Institute of Scientific and Technical Information of China (English)

    孙皖; 马斌; 牛璐; 侯予

    2013-01-01

    The binary mixture properties of cryogenic air were fitted by the PR equations and the zero pressure polynomial.The single-phase flow under the design conditions and the equilibrium condensation of two-phase flow at higher pressure and lower temperature were numerically simulated by ANSYS CFX.For a cryogenic turboexpander in air separation process,the temperature field,pressure field,streamlines and liquid mass fraction in the nozzle and impeller were obtained.The isentropic efficiency of the turboexpander was calculated.The results show that the eddy occurring on the suction side of the impeller would delay the phase-change condensation,and the wake at the trailing edge of the blade would lead to the decrease in the local liquid mass fraction.The simulation results agree well with the experimental data,confirming that the model of the equilibrium condensation can be applied to the simulation of the two-phase flow turboexpander having a small liquid mass fraction.%采用Peng-Robinson方程及零压多项式拟合了低温空气二元混合物的物性,利用商业软件ANSYS CFX对设计工况下的单相流动及进口升压降温后平衡凝结两相流动进行了数值模拟,得到了全低压空气分离流程中的低温两相透平膨胀机喷嘴和工作轮的温度场、压力场、流线及带液量云图,同时推导了该工况下膨胀机的等熵效率.结果表明,工作轮流道内吸力面壁面处的涡流会延迟凝结相变发生,叶片后缘处的尾迹使得吸力面壁面处的带液量有所减小.最后,通过实验验证了模拟结果,表明利用平衡凝结相变模型能够模拟小带液量透平膨胀机流道内的两相流动.该结果可为低温两相膨胀机研究提供参考.

  18. Research on the Conductivity-Based Detection Principles of Bubbles in Two-Phase Flows and the Design of a Bubble Sensor for CBM Wells

    Directory of Open Access Journals (Sweden)

    Chuan Wu

    2016-09-01

    Full Text Available The parameters of gas-liquid two-phase flow bubbles in field coalbed methane (CBM wells are of great significance for analyzing coalbed methane output, judging faults in CBM wells, and developing gas drainage and extraction processes, which stimulates an urgent need for detecting bubble parameters for CBM wells in the field. However, existing bubble detectors cannot meet the requirements of the working environments of CBM wells. Therefore, this paper reports findings on the principles of measuring the flow pattern, velocity, and volume of two-phase flow bubbles based on conductivity, from which a new bubble sensor was designed. The structural parameters and other parameters of the sensor were then computed, the “water film phenomenon” produced by the sensor was analyzed, and the appropriate materials for making the sensor were tested and selected. After the sensor was successfully devised, laboratory tests and field tests were performed, and the test results indicated that the sensor was highly reliable and could detect the flow patterns of two-phase flows, as well as the quantities, velocities, and volumes of bubbles. With a velocity measurement error of ±5% and a volume measurement error of ±7%, the sensor can meet the requirements of field use. Finally, the characteristics and deficiencies of the bubble sensor are summarized based on an analysis of the measurement errors and a comparison of existing bubble-measuring devices and the designed sensor.

  19. Research on the Conductivity-Based Detection Principles of Bubbles in Two-Phase Flows and the Design of a Bubble Sensor for CBM Wells.

    Science.gov (United States)

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-09-17

    The parameters of gas-liquid two-phase flow bubbles in field coalbed methane (CBM) wells are of great significance for analyzing coalbed methane output, judging faults in CBM wells, and developing gas drainage and extraction processes, which stimulates an urgent need for detecting bubble parameters for CBM wells in the field. However, existing bubble detectors cannot meet the requirements of the working environments of CBM wells. Therefore, this paper reports findings on the principles of measuring the flow pattern, velocity, and volume of two-phase flow bubbles based on conductivity, from which a new bubble sensor was designed. The structural parameters and other parameters of the sensor were then computed, the "water film phenomenon" produced by the sensor was analyzed, and the appropriate materials for making the sensor were tested and selected. After the sensor was successfully devised, laboratory tests and field tests were performed, and the test results indicated that the sensor was highly reliable and could detect the flow patterns of two-phase flows, as well as the quantities, velocities, and volumes of bubbles. With a velocity measurement error of ±5% and a volume measurement error of ±7%, the sensor can meet the requirements of field use. Finally, the characteristics and deficiencies of the bubble sensor are summarized based on an analysis of the measurement errors and a comparison of existing bubble-measuring devices and the designed sensor.

  20. Discovering and understanding android sensor usage behaviors with data flow analysis

    KAUST Repository

    Liu, Xing

    2017-03-20

    Today’s Android-powered smartphones have various embedded sensors that measure the acceleration, orientation, light and other environmental conditions. Many functions in the third-party applications (apps) need to use these sensors. However, embedded sensors may lead to security issues, as the third-party apps can read data from these sensors without claiming any permissions. It has been proven that embedded sensors can be exploited by well designed malicious apps, resulting in leaking users’ privacy. In this work, we are motivated to provide an overview of sensor usage patterns in current apps by investigating what, why and how embedded sensors are used in the apps collected from both a Chinese app. market called “AppChina” and the official market called “Google Play”. To fulfill this goal, We develop a tool called “SDFDroid” to identify the used sensors’ types and to generate the sensor data propagation graphs in each app. We then cluster the apps to find out their sensor usage patterns based on their sensor data propagation graphs. We apply our method on 22,010 apps collected from AppChina and 7,601 apps from Google Play. Extensive experiments are conducted and the experimental results show that most apps implement their sensor related functions by using the third-party libraries. We further study the sensor usage behaviors in the third-party libraries. Our results show that the accelerometer is the most frequently used sensor. Though many third-party libraries use no more than four types of sensors, there are still some third-party libraries registering all the types of sensors recklessly. These results call for more attentions on better regulating the sensor usage in Android apps.

  1. Test method for measuring insulation values of cryogenic pipes

    NARCIS (Netherlands)

    Velthuis, J.F.M.; Blokland, H.; Klaver, B.W.; Beld, C. van de

    2010-01-01

    In this paper a large-area heat flux and temperature sensor (HFT) is used for the evaluation of the insulation value of cryogenic pipes. The HFT is flexible and clamp-on. The test method is relatively simple and can be used in-situ. The HFT makes it possible to monitor insulation performance over el

  2. Test method for measuring insulation values of cryogenic pipes

    NARCIS (Netherlands)

    Velthuis, J.F.M.; Blokland, H.; Klaver, B.W.; Beld, C. van de

    2010-01-01

    In this paper a large-area heat flux and temperature sensor (HFT) is used for the evaluation of the insulation value of cryogenic pipes. The HFT is flexible and clamp-on. The test method is relatively simple and can be used in-situ. The HFT makes it possible to monitor insulation performance over

  3. Cryogenics Research and Engineering Experience

    Science.gov (United States)

    Toro Medina, Jaime A.

    2013-01-01

    Energy efficient storage, transfer and use of cryogens and cryogenic propellants on Earth and in space have a direct impact on NASA, government and commercial programs. Research and development on thermal insulation, propellant servicing, cryogenic components, material properties and sensing technologies provides industry, government and research institutions with the cross-cutting technologies to manage low-temperature applications. Under the direction of the Cryogenic Testing Lab at Kennedy Space Center, the work experience acquired allowed me to perform research, testing, design and analysis of current and future cryogenic technologies to be applied in several projects.

  4. A prototype of an electric-discharge gas flow oxygen−iodine laser: I. Modeling of the processes of singlet oxygen generation in a transverse cryogenic slab RF discharge

    Energy Technology Data Exchange (ETDEWEB)

    Vagin, N. P.; Ionin, A. A., E-mail: aion@sci.lebedev.ru; Kochetov, I. V.; Napartovich, A. P.; Sinitsyn, D. V., E-mail: dsinit@sci.lebedev.ru; Yuryshev, N. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2017-03-15

    The existing kinetic model describing self-sustained and electroionization discharges in mixtures enriched with singlet oxygen has been modified to calculate the characteristics of a flow RF discharge in molecular oxygen and its mixtures with helium. The simulations were performed in the gas plug-flow approximation, i.e., the evolution of the plasma components during their motion along the channel was represented as their evolution in time. The calculations were carried out for the O{sub 2}: He = 1: 0, 1: 1, 1: 2, and 1: 3 mixtures at an oxygen partial pressure of 7.5 Torr. It is shown that, under these conditions, volumetric gas heating in a discharge in pure molecular oxygen prevails over gas cooling via heat conduction even at an electrode temperature as low as ~100 K. When molecular oxygen is diluted with helium, the behavior of the gas temperature changes substantially: heat removal begins to prevail over volumetric gas heating, and the gas temperature at the outlet of the discharge zone drops to ~220–230 K at room gas temperature at the inlet, which is very important in the context of achieving the generation threshold in an electric-discharge oxygen−iodine laser based on a slab cryogenic RF discharge.

  5. Novel miniaturized sensors for potentiometric batch and flow-injection analysis (FIA) of perchlorate in fireworks and propellants.

    Science.gov (United States)

    Almeer, Saeed H M A; Zogby, Ibrahim A; Hassan, Saad S M

    2014-11-01

    Three planar miniaturized perchlorate membrane sensors (3×5 mm(2)) are prepared using a flexible Kaptan substrate coated with nitron-perchlorate (NT-ClO4) [sensor 1], methylene blue-perchlorate (MB-ClO4) [sensor II] and indium-porphyrin (In-Por) [sensor III] as electroactive materials in PVC membranes plasticized with 2-NPPE. Sensors I, II and III display near-Nernstian response for 1.0×10(-5)-1.0×10(-2), 3.1×10(-5)-1.0×10(-2) and 3.1×10(-6)-1.0×10(-2) mol L(-1) ClO4(-) with lower detection limits of 6.1×10(-6), 6.9×10(-6) and 1.2×10(-6) mol L(-1), and anionic calibration slopes of 50.9±0.4, 48.4±0.4 and 57.7±0.3 mV decade(-1), respectively. Methods for determining perchlorate using these sensors offer many attractive advantages including simplicity, flexibility, cost effectiveness, wide linear dynamic response range (0.1-1000 ppm), low detection limit (sensors show high selectivity in the presence of some inorganic ions (e.g., PO4(3-), SO4(2-), S2O3(2-), NO2(-), NO3(-), N3(-), CN(-), Cl(-), Br(-), I(-)) and automation feasibility. Indium-porphyrin based membrane sensor (sensor III) is used as a detector in a wall-jet flow injection set-up to enable accurate flow injection analysis (FIA) of perchlorate in some fireworks without interferences from the associated reducing agents (sulfur and charcoal), binders (dextrin, lactose), coloring agents (calcium, strontium, copper, iron, sodium), color brighten (linseed oil) and regulators (aluminum flakes) which are commonly used in the formulations. The sensor is also used for perchlorate assessment in some propellant powders. The results fairly agree with data obtained by ion-chromatography.

  6. High Power Cryogenic Targets

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Smith

    2011-08-01

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  7. Cryogenic current leads

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, F.

    1982-01-01

    Theoretical, technical and design questions are examined of cryogenic current leads for SP of magnetic systems. Simplified mathematical models are presented for the current leads. To illustrate modeling, the calculation is made of the real current leads for 500 A and three variants of current leads for 1500 A for the enterprise ''Shkoda.''

  8. The measurement of gas-liquid two-phase flows in a small diameter pipe using a dual-sensor multi-electrode conductance probe

    Science.gov (United States)

    Zhai, Lu-Sheng; Bian, Peng; Han, Yun-Feng; Gao, Zhong-Ke; Jin, Ning-De

    2016-04-01

    We design a dual-sensor multi-electrode conductance probe to measure the flow parameters of gas-liquid two-phase flows in a vertical pipe with an inner diameter of 20 mm. The designed conductance probe consists of a phase volume fraction sensor (PVFS) and a cross-correlation velocity sensor (CCVS). Through inserting an insulated flow deflector in the central part of the pipe, the gas-liquid two-phase flows are forced to pass through an annual space. The multiple electrodes of the PVFS and the CCVS are flush-mounted on the inside of the pipe wall and the outside of the flow deflector, respectively. The geometry dimension of the PVFS is optimized based on the distribution characteristics of the sensor sensitivity field. In the flow loop test of vertical upward gas-liquid two-phase flows, the output signals from the dual-sensor multi-electrode conductance probe are collected by a data acquisition device from the National Instruments (NI) Corporation. The information transferring characteristics of local flow structures in the annular space are investigated using the transfer entropy theory. Additionally, the kinematic wave velocity is measured based on the drift velocity model to investigate the propagation behavior of the stable kinematic wave in the annular space. Finally, according to the motion characteristics of the gas-liquid two-phase flows, the drift velocity model based on the flow patterns is constructed to measure the individual phase flow rate with higher accuracy.

  9. Mass flow rate measurements in gas-liquid flows by means of a venturi or orifice plate coupled to a void fraction sensor

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Jorge Luiz Goes; Passos, Julio Cesar [Departamento de Engenharia Mecanica-LEPTEN/Boiling-UFSC, Campus Universitario, Trindade, 88.040-900 Florianopolis-SC (Brazil); Verschaeren, Ruud; Geld, Cees van der [Eindhoven University of Technology, Faculty of Mechanical Engineering, W-hoog 2.135, P.O. Box 513, 5600 MB, Eindhoven (Netherlands)

    2009-01-15

    Two-phase flow measurements were carried out using a resistive void fraction meter coupled to a venturi or orifice plate. The measurement system used to estimate the liquid and gas mass flow rates was evaluated using an air-water experimental facility. Experiments included upward vertical and horizontal flow, annular, bubbly, churn and slug patterns, void fraction ranging from 2% to 85%, water flow rate up to 4000 kg/h, air flow rate up to 50 kg/h, and quality up to almost 10%. The fractional root mean square (RMS) deviation of the two-phase mass flow rate in upward vertical flow through a venturi plate is 6.8% using the correlation of Chisholm (D. Chisholm, Pressure gradients during the flow of incompressible two-phase mixtures through pipes, venturis and orifice plates, British Chemical Engineering 12 (9) (1967) 454-457). For the orifice plate, the RMS deviation of the vertical flow is 5.5% using the correlation of Zhang et al. (H.J. Zhang, W.T. Yue, Z.Y. Huang, Investigation of oil-air two-phase mass flow rate measurement using venturi and void fraction sensor, Journal of Zhejiang University Science 6A (6) (2005) 601-606). The results show that the flow direction has no significant influence on the meters in relation to the pressure drop in the experimental operation range. Quality and slip ratio analyses were also performed. The results show a mean slip ratio lower than 1.1, when bubbly and slug flow patterns are encountered for mean void fractions lower than 70%. (author)

  10. Unmanned Aerial Vehicle Navigation Using Wide-Field Optical Flow and Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Matthew B. Rhudy

    2015-01-01

    Full Text Available This paper offers a set of novel navigation techniques that rely on the use of inertial sensors and wide-field optical flow information. The aircraft ground velocity and attitude states are estimated with an Unscented Information Filter (UIF and are evaluated with respect to two sets of experimental flight data collected from an Unmanned Aerial Vehicle (UAV. Two different formulations are proposed, a full state formulation including velocity and attitude and a simplified formulation which assumes that the lateral and vertical velocity of the aircraft are negligible. An additional state is also considered within each formulation to recover the image distance which can be measured using a laser rangefinder. The results demonstrate that the full state formulation is able to estimate the aircraft ground velocity to within 1.3 m/s of a GPS receiver solution used as reference “truth” and regulate attitude angles within 1.4 degrees standard deviation of error for both sets of flight data.

  11. Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

    Science.gov (United States)

    Diaz, Carlos E., Jr.

    2015-01-01

    This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

  12. Calibration in a potential water jet of a five-hole pressure probe with embedded sensors for unsteady flow measurement

    Science.gov (United States)

    Duquesne, P.; Desch"nes, C.; Iliescu, M.; Ciocan, G. D.

    2010-03-01

    Investigations of the flow behavior are currently carried out experimentally on models of hydraulic turbines. Quantities such as unsteady velocity can be acquired using PIV or LDV techniques, static wall pressure using steady or unsteady pressure transducers and wall shear stress using hot-film anemometry. More rarely acquired however, the unsteady total pressure at different locations in the flowstream would give more information on the flow dynamics and would be a key component for setting boundary conditions for CFD simulations. Following the example of classical Pitot tubes, which can only give averaged pressure values though, we have developed a five-hole pressure probe with embedded sensors that can measure unsteady values of total pressure, local flow velocity and direction. The probe head is designed to have a minimum impact on the flowstream, and the miniature sensors are placed in a cross configuration compared to the probe's support axis. This paper focuses on the utilization of normalized calibration coefficients and their use for unsteady values, and on the justification for using our cross sensor repartition. The calibration setup is presented briefly, including a water potential jet that requires the calculation of specific calibration coefficients. Different phenomena were observed during experimentation. Their impact on the accuracy of the probe is analyzed. The probe's operation range for this particular calibration setup is discussed. Finally, we focus on the influence of the sensors repartition on the tridimensional shape of the calibration coefficients, and we provide a way to calculate the first approximate solution for the reverse calculus while the sensors are not aligned with the probe's arm.

  13. Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach

    Directory of Open Access Journals (Sweden)

    Lam Ghai Lim

    2016-07-01

    Full Text Available A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a ‘sine-like’ function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function, with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design.

  14. An advanced thin foil sensor concept for heat flux and heat transfer measurements in fully turbulent flows

    Science.gov (United States)

    Mocikat, H.; Herwig, H.

    2007-02-01

    A double layer hot film with two 10 μm nickel foils, separated by a 25 μm polyimide foil is used as a multi-purpose sensor. Each foil can be operated as a (calibrated) temperature sensor in its passive mode by imposing an electric current small enough to avoid heating by dissipation of electrical energy. Alternatively, however, each foil can also serve as a heater in an active mode with electric currents high enough to cause Joule heating. This double foil sensor can be used as a conventional heat flux sensor in its passive mode when mounted on an externally heated surface. Together with the wall and free stream temperature this measured heat flux will provide the local heat transfer coefficient h = dot{q}w/left(Tw - T_{infty}right). In fully turbulent flows it alternatively can be operated in an active mode on a cold, i.e. not externally heated surface. Then, by heating the upper foil, a local heat transfer is initiated from which the local heat transfer coefficient h can be determined, once the lower foil is heated to the same temperature as the upper one, thus acting as a counter-heater. The overall concept behind this mode of measurement is based on the local character of heat transfer in fully turbulent flows which turns out to be almost independent of the upstream thermal events.

  15. Diagnostics of two-phase flows with high concentration of a solid dispersed phase using fiber-optic sensors

    Science.gov (United States)

    Evseev, A. R.

    2016-10-01

    This paper is focused on the physical modeling of two-phase flows with high concentration of the dispersed phase. The fiber-optical sensors and their calibration procedure were developed for bubble concentration measurements in the fluidized bed apparatus (FB). Distributions of bubble concentration in the 2D and 3D FB apparatuses, which determine the quality of fluidization and local density of filling material, were obtained. The techniques of particle velocity and concentration measurements in the circulating fluidized bed (CFB) was developed using three-fiber sensor (the differential scheme of LDA) operated in backscattering regime. Sensor operation was analyzed and the main systematic measurement errors were determined; the original construction of the sensor was designed. The data on the velocity and concentration profiles of dispersed phase in a large-scale CFB apparatus were obtained for fluidization of particles by air. It was found that with increasing circulation velocity in the CFB apparatus, the particle concentration increases in the near-wall region much higher than in the flow core. The method of particle velocity measurements in a liquid was developed using the laser Doppler fiber anemometer (LDFA-1), operating in the backscattering regime. The signal to noise ratio was obtained for particles of different size and material in test measurements. The rates of consolidated precipitation of cryolite particles in a sedimentation apparatus with the inclined walls were measured.

  16. Photonic Low Cost Micro-Sensor for in-Line Wear Particle Detection in Flowing Lube Oils

    Directory of Open Access Journals (Sweden)

    Jon Mabe

    2017-03-01

    Full Text Available The presence of microscopic particles in suspension in industrial fluids is often an early warning of latent or imminent failures in the equipment or processes where they are being used. This manuscript describes work undertaken to integrate different photonic principles with a micro- mechanical fluidic structure and an embedded processor to develop a fully autonomous wear debris sensor for in-line monitoring of industrial fluids. Lens-less microscopy, stroboscopic illumination, a CMOS imager and embedded machine vision technologies have been merged to develop a sensor solution that is able to detect and quantify the number and size of micrometric particles suspended in a continuous flow of a fluid. A laboratory test-bench has been arranged for setting up the configuration of the optical components targeting a static oil sample and then a sensor prototype has been developed for migrating the measurement principles to real conditions in terms of operating pressure and flow rate of the oil. Imaging performance is quantified using micro calibrated samples, as well as by measuring real used lubricated oils. Sampling a large fluid volume with a decent 2D spatial resolution, this photonic micro sensor offers a powerful tool at very low cost and compacted size for in-line wear debris monitoring.

  17. Photonic Low Cost Micro-Sensor for in-Line Wear Particle Detection in Flowing Lube Oils

    Science.gov (United States)

    Mabe, Jon; Zubia, Joseba; Gorritxategi, Eneko

    2017-01-01

    The presence of microscopic particles in suspension in industrial fluids is often an early warning of latent or imminent failures in the equipment or processes where they are being used. This manuscript describes work undertaken to integrate different photonic principles with a micro- mechanical fluidic structure and an embedded processor to develop a fully autonomous wear debris sensor for in-line monitoring of industrial fluids. Lens-less microscopy, stroboscopic illumination, a CMOS imager and embedded machine vision technologies have been merged to develop a sensor solution that is able to detect and quantify the number and size of micrometric particles suspended in a continuous flow of a fluid. A laboratory test-bench has been arranged for setting up the configuration of the optical components targeting a static oil sample and then a sensor prototype has been developed for migrating the measurement principles to real conditions in terms of operating pressure and flow rate of the oil. Imaging performance is quantified using micro calibrated samples, as well as by measuring real used lubricated oils. Sampling a large fluid volume with a decent 2D spatial resolution, this photonic micro sensor offers a powerful tool at very low cost and compacted size for in-line wear debris monitoring. PMID:28335436

  18. Evaluation of event-based algorithms for optical flow with ground-truth from inertial measurement sensor

    Directory of Open Access Journals (Sweden)

    Bodo eRückauer

    2016-04-01

    Full Text Available In this study we compare nine optical flow algorithms that locally measure the flow normal to edges according to accuracy and computation cost. In contrast to conventional, frame-based motion flow algorithms, our open-source implementations compute optical flow based on address-events from a neuromorphic Dynamic Vision Sensor (DVS. For this benchmarking we created a dataset of two synthesized and three real samples recorded from a 240x180 pixel Dynamic and Active-pixel Vision Sensor (DAVIS. This dataset contains events from the DVS as well as conventional frames to support testing state-of-the-art frame-based methods. We introduce a new source for the ground truth: In the special case that the perceived motion stems solely from a rotation of the vision sensor around its three camera axes, the true optical flow can be estimated using gyro data from the inertial measurement unit integrated with the DAVIS camera. This provides a ground-truth to which we can compare algorithms that measure optical flow by means of motion cues. An analysis of error sources led to the use of a refractory period, more accurate numerical derivatives and a Savitzky-Golay filter to achieve significant improvements in accuracy. Our pure Java implementations of two recently published algorithms reduce computational cost by up to 29% compared to the original implementations. Two of the algorithms introduced in this paper further speed up processing by a factor of 10 compared with the original implementations, at equal or better accuracy. On a desktop PC, they run in real-time on dense natural input recorded by a DAVIS camera.

  19. Evaluation of Event-Based Algorithms for Optical Flow with Ground-Truth from Inertial Measurement Sensor.

    Science.gov (United States)

    Rueckauer, Bodo; Delbruck, Tobi

    2016-01-01

    In this study we compare nine optical flow algorithms that locally measure the flow normal to edges according to accuracy and computation cost. In contrast to conventional, frame-based motion flow algorithms, our open-source implementations compute optical flow based on address-events from a neuromorphic Dynamic Vision Sensor (DVS). For this benchmarking we created a dataset of two synthesized and three real samples recorded from a 240 × 180 pixel Dynamic and Active-pixel Vision Sensor (DAVIS). This dataset contains events from the DVS as well as conventional frames to support testing state-of-the-art frame-based methods. We introduce a new source for the ground truth: In the special case that the perceived motion stems solely from a rotation of the vision sensor around its three camera axes, the true optical flow can be estimated using gyro data from the inertial measurement unit integrated with the DAVIS camera. This provides a ground-truth to which we can compare algorithms that measure optical flow by means of motion cues. An analysis of error sources led to the use of a refractory period, more accurate numerical derivatives and a Savitzky-Golay filter to achieve significant improvements in accuracy. Our pure Java implementations of two recently published algorithms reduce computational cost by up to 29% compared to the original implementations. Two of the algorithms introduced in this paper further speed up processing by a factor of 10 compared with the original implementations, at equal or better accuracy. On a desktop PC, they run in real-time on dense natural input recorded by a DAVIS camera.

  20. Formation, characterization, and flow dynamics of nanostructure modified sensitive and selective gas sensors based on porous silicon

    Science.gov (United States)

    Ozdemir, Serdar

    Nanopore covered microporous silicon interfaces have been formed via an electrochemical etch for gas sensor applications. Rapid reversible and sensitive gas sensors have been fabricated. Both top-down and bottom-up approaches are utilized in the process. A nano-pore coated micro-porous silicon surface is modified selectively for sub-ppm detection of NH3, PH3 , NO, H2S, SO2. The selective depositions include electrolessly generated SnO2, CuxO, Au xO, NiO, and nanoparticles such as TiO2, MgO doped TiO 2, Al2O3, and ZrO2. Flow dynamics are analyzed via numerical simulations and response data. An array of sensors is formed to analyze mixed gas response. A general coating selection method for chemical sensors is established via an extrapolation on the inverse of the Hard-Soft Acid-Base concept. In Chapter 1, the current state of the porous silicon gas sensor research is reviewed. Since metal oxide thin films, and, recently, nanowires are dominantly used for sensing application, the general properties of metal oxides are also discussed in this chapter. This chapter is concluded with a discussion about commercial gas sensors and the advantages of using porous silicon as a sensing material. The PS review discussed at the beginning of this chapter is an overview of the following publication: (1) "The Potential of Porous Silicon Gas Sensors", Serdar Ozdemir, James L. Gole, Current Opinion in Solid State and Materials Science, 11, 92-100 (2007). In Chapter 2, porous silicon formation is explained in detail. Interesting results of various silicon anodization experiments are discussed. In the second part of this chapter, the microfabrication process of porous silicon conductometric gas sensors and gas testing set up are briefly introduced. In chapter 3, metal oxide nanoparticle/nanocluster formation and characterization experiments via SEM and XPS analysis are discussed. Chapter 4 is an overview of the test results for various concentrations NH3, NO, NO2 and PH3. The

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

    Science.gov (United States)

    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

  2. VOST Flow-Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Two cryogenic flow-control valves of diameters 1/2" and 2" will be built and tested. Based on cryogenically-proven Venturi Off-Set Technology (VOST) they have no...

  3. Conductometric Sensor for Soot Mass Flow Detection in Exhausts of Internal Combustion Engines

    Directory of Open Access Journals (Sweden)

    Markus Feulner

    2015-11-01

    Full Text Available Soot sensors are required for on-board diagnostics (OBD of automotive diesel particulate filters (DPF to detect filter failures. Widely used for this purpose are conductometric sensors, measuring an electrical current or resistance between two electrodes. Soot particles deposit on the electrodes, which leads to an increase in current or decrease in resistance. If installed upstream of a DPF, the “engine-out” soot emissions can also be determined directly by soot sensors. Sensors were characterized in diesel engine real exhausts under varying operation conditions and with two different kinds of diesel fuel. The sensor signal was correlated to the actual soot mass and particle number, measured with an SMPS. Sensor data and soot analytics (SMPS agreed very well, an impressing linear correlation in a double logarithmic representation was found. This behavior was even independent of the used engine settings or of the biodiesel content.

  4. Voidage Measurement of Air-Water Two-phase Flow Based on ERT Sensor and Data Mining Technology

    Institute of Scientific and Technical Information of China (English)

    王保良; 孟振振; 黄志尧; 冀海峰; 李海青

    2012-01-01

    Based on an electrical resistance tomography(ERT) sensor and the data mining technology,a new voidage measurement method is proposed for air-water two-phase flow.The data mining technology used in this work is a least squares support vector machine(LS-SVM) algorithm together with the feature extraction method,and three feature extraction methods are tested:principal component analysis(PCA),partial least squares(PLS) and independent component analysis(ICA).In the practical voidage measurement process,the flow pattern is firstly identified directly from the conductance values obtained by the ERT sensor.Then,the appropriate voidage measurement model is selected according to the flow pattern identification result.Finally,the voidage is calculated.Experimental results show that the proposed method can measure the voidage effectively,and the measurement accuracy and speed are satisfactory.Compared with the conventional voidage measurement methods based on ERT,the proposed method doesn't need any image reconstruction process,so it has the advantage of good real-time performance.Due to the introduction of flow pattern identification,the influence of flow pattern on the voidage measurement is overcome.Besides,it is demonstrated that the LS-SVM method with PLS feature extraction presents the best measurement performance among the tested methods.

  5. Fabrication of a polyvinylidene difluoride fiber with a metal core and its application as directional air flow sensor

    Science.gov (United States)

    Bian, Yixiang; Liu, Rongrong; Hui, Shen

    2016-09-01

    We fabricated a sensitive air flow detector that mimic the sensing mechanism found at the tail of some insects. [see Y. Yang, A. Klein, H. Bleckmann and C. Liu, Appl. Phys. Lett. 99(2) (2011); J. J. Heys, T. Gedeon, B. C. Knott and Y. Kim, J. Biomech. 41(5), 977 (2008); J. Tao and X. Yu, Smart Mat. Struct. 21(11) (2012)]. Our bionic airflow sensor uses a polyvinylidene difluoride (PVDF) microfiber with a molybdenum core which we produced with the hot extrusion tensile method. The surface of the fiber is partially coated with conductive silver adhesive that serve as surface electrodes. A third electrode, the metal core is used to polarize polyvinylidene difluoride (PVDF) under the surface electrodes. The cantilever beam structure of the prepared symmetric electrodes of metal core piezoelectric fiber (SMPF) is used as the artificial hair airflow sensor. The surface electrodes are used to measure output voltage. Our theoretical and experimental results show that the SMPF responds fast to air flow changes, the output charge has an exponential correlation with airflow velocity and a cosine relation with the direction of airflow. Our bionic airflow sensor with directional sensing ability can also measure air flow amplitude. [see H. Droogendijk, R. G. P. Sanders and G. J. M. Krijnen, New J. Phys. 15 (2013)]. By using two surface electrodes, our sensing circuit further improves sensitivity.

  6. A flowing liquid test system for assessing the linearity and time-response of rapid fibre optic oxygen partial pressure sensors.

    Science.gov (United States)

    Chen, R; Hahn, C E W; Farmery, A D

    2012-08-15

    The development of a methodology for testing the time response, linearity and performance characteristics of ultra fast fibre optic oxygen sensors in the liquid phase is presented. Two standard medical paediatric oxygenators are arranged to provide two independent extracorporeal circuits. Flow from either circuit can be diverted over the sensor under test by means of a system of rapid cross-over solenoid valves exposing the sensor to an abrupt change in oxygen partial pressure, P O2. The system is also capable of testing the oxygen sensor responses to changes in temperature, carbon dioxide partial pressure P CO2 and pH in situ. Results are presented for a miniature fibre optic oxygen sensor constructed in-house with a response time ≈ 50 ms and a commercial fibre optic sensor (Ocean Optics Foxy), when tested in flowing saline and stored blood.

  7. Cavitation instabilities of an inducer in a cryogenic pump

    Science.gov (United States)

    Kim, Dae-Jin; Sung, Hyung Jin; Choi, Chang-Ho; Kim, Jin-Sun

    2017-03-01

    Inducers assist cryogenic pumps to operate safely under cavitation conditions by increasing the pressure of the impeller inlet, but create cavitation instabilities. The use of cryogenic fluids requires special attention because of safety and handling concerns. To examine the cavitation instabilities of a cryogenic pump, two kinds of working fluids, water and liquid oxygen, were employed. The cavitation instabilities were measured with an accelerometer installed on the pump casing. The flow coefficient and the head slightly decrease with decreases in the cavitation number before the cavitation breakdown. These trends are true of both fluids. Several cavitation instabilities were identified with the accelerometer. At lower flow coefficients, super-synchronous rotating cavitation was found in a similar cavitation number range for both fluids. At higher flow coefficients, the cavitation numbers of the cavitation instabilities in the liquid oxygen test are smaller than those of the water test.

  8. Cryogenic treatment of gas

    Science.gov (United States)

    Bravo, Jose Luis [Houston, TX; Harvey, III, Albert Destrehan; Vinegar, Harold J [Bellaire, TX

    2012-04-03

    Systems and methods of treating a gas stream are described. A method of treating a gas stream includes cryogenically separating a first gas stream to form a second gas stream and a third stream. The third stream is cryogenically contacted with a carbon dioxide stream to form a fourth and fifth stream. A majority of the second gas stream includes methane and/or molecular hydrogen. A majority of the third stream includes one or more carbon oxides, hydrocarbons having a carbon number of at least 2, one or more sulfur compounds, or mixtures thereof. A majority of the fourth stream includes one or more of the carbon oxides and hydrocarbons having a carbon number of at least 2. A majority of the fifth stream includes hydrocarbons having a carbon number of at least 3 and one or more of the sulfur compounds.

  9. Cryogenic Control System

    Energy Technology Data Exchange (ETDEWEB)

    Goloborod' ko, S.; /Fermilab

    1989-02-27

    The control system (CS) for the cryogenic arrangement of the DO Liquid Argon Calorimeter consists of a Texas instruments 560/565 Programmable Logical Controller (PLC), two remote bases with Remote Base Controllers and a corresponding set of input/output (I/O) modules, and a PC AST Premium 286 (IBM AT Compatible). The PLC scans a set of inputs and provides a set of outputs based on a ladder logic program and PID control loops. The inputs are logic or analog (current, voltage) signals from equipment status switches or transducers. The outputs are logic or analog (current or voltage) signals for switching solenoids and positioning pneumatic actuators. Programming of the PLC is preformed by using the TISOFT2/560/565 package, which is installed in the PC. The PC communicates to the PLC through a serial RS232 port and provides operator interface to the cryogenic process using Xpresslink software.

  10. Cryogenic treatment of gas

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, Jose Luis [Houston, TX; Harvey, III, Albert Destrehan (Kingwood, TX); Vinegar, Harold J [Bellaire, TX

    2012-04-03

    Systems and methods of treating a gas stream are described. A method of treating a gas stream includes cryogenically separating a first gas stream to form a second gas stream and a third stream. The third stream is cryogenically contacted with a carbon dioxide stream to form a fourth and fifth stream. A majority of the second gas stream includes methane and/or molecular hydrogen. A majority of the third stream includes one or more carbon oxides, hydrocarbons having a carbon number of at least 2, one or more sulfur compounds, or mixtures thereof. A majority of the fourth stream includes one or more of the carbon oxides and hydrocarbons having a carbon number of at least 2. A majority of the fifth stream includes hydrocarbons having a carbon number of at least 3 and one or more of the sulfur compounds.

  11. Ionophore-Based Potentiometric Sensors for the Flow-Injection Determination of Promethazine Hydrochloride in Pharmaceutical Formulations and Human Urine

    Directory of Open Access Journals (Sweden)

    Suad Mustafa Al-Araji

    2011-01-01

    Full Text Available Plasticised poly(vinyl chloride-based membranes containing the ionophores (α-, β- and γ-cyclodextrins (CD, dibenzo-18-crown-6 (DB18C6 and dibenzo-30-crown-10 (DB30C10 were evaluated for their potentiometric response towards promethazine (PM in a flow injection analysis (FIA set-up. Good responses were obtained when β- and γ-CDs, and DB30C10 were used. The performance characteristics were further improved when tetrakis(4-chlorophenyl borate (KTPB was added to the membrane. The sensor based on β-CD, bis(2-ethylhexyl adipate (BEHA and KTPB exhibited the best performance among the eighteen sensor compositions that were tested. The response was linear from 1 x 10−5 to 1 x 10−2 M, slope was 61.3 mV decade−1, the pH independent region ranged from 4.5 to 7.0, a limit of detection of 5.3 x 10−6 M was possible and a lifetime of more than a month was observed when used in the FIA system. Other plasticisers such as dioctyl phenylphosphonate and tributyl phosphate do not show significant improvements in the quality of the sensors. The promising sensors were further tested for the effects of foreign ions (Li+, Na+, K+, Mg2+, Ca2+, Co2+, Cu2+, Cr3+, Fe3+, glucose, fructose. FIA conditions (e.g., effects of flow rate, injection volume, pH of the carrier stream were also studied when the best sensor was used (based on β-CD. The sensor was applied to the determination of PM in four pharmaceutical preparations and human urine that were spiked with different levels of PM. Good agreement between the sensor and the manufacturer’s claimed values (for pharmaceutical preparations was obtained, while mean recoveries of 98.6% were obtained for spiked urine samples. The molecular recognition features of the sensors as revealed by molecular modelling were rationalised by the nature of the interactions and complexation energies between the host and guest molecules.

  12. Cryogenic Selective Surfaces

    Science.gov (United States)

    Youngquist, Robert; Nurge, Mark; Gibson, Tracy; Johnson, Wesley

    2017-01-01

    The NASA Innovative Advanced Concept (NIAC) program has been funding work at KSC on a novel coating that should allow cryogenic materials to be stored in deep space. The NIAC Symposium will be the last week of September and it is a requirement that the funded material be presented both orally and at a poster session. This DAA submission is requesting approval to go public with both the presentation and the poster.

  13. Cryogenic Test Technology 1984.

    Science.gov (United States)

    1985-04-01

    aircraft configuration Pathfinder II (Figure 16) made of Vascomax 200, a set of six bodies of revolution (Figure 17) made from 6061 aluminium alloy, a...iron and aluminium alloys appear to be viable candidates. AS loads increase the number of avail- able alloys is severely constrained by toughness...using A-286 screws in four steels and one aluminium alloy. In the absence of loads cryogenic cycling gene- rally produced decreases in breakaway

  14. Advances in Helium Cryogenics

    Science.gov (United States)

    Sciver, S. W. Van

    This review provides a survey of major advances that have occurred in recent years in the area of helium cryogenics. Helium-temperature cryogenics is the enabling technology for a substantial and growing number of low-temperature systems from superconducting magnets to space-based experimental facilities. In recent years there have been many advances in the technology of low-temperature helium, driven mostly by new applications. However, to keep the review from being too broad, this presentation focuses mainly on three of the most significant advances. These are: (1) the development of large-scale recuperative refrigeration systems mainly for superconducting magnet applications in accelerators and other research facilities; (2) the use of stored superfluid helium (He II) as a coolant for spacebased astrophysics experiments; and (3) the application of regenerative cryocoolers operating at liquid helium temperatures primarily for cooling superconducting devices. In each case, the reader should observe that critical technologies were developed to facilitate these applications. In addition to these three primary advances, other significant helium cryogenic technologies are briefly reviewed at the end of this chapter, along with some vision for future developments in these areas.

  15. Optimisation of a two-wire thermal sensor for flow and sound measurements

    NARCIS (Netherlands)

    Honschoten, van J.W.; Krijnen, G.J.M.; Svetovoy, V.B.; Bree, de H.E.; Elwenspoek, M.C.

    2001-01-01

    The Microflown is an acoustic sensor measuring particle velocity instead of pressure, which is usually measured by conventional microphones. In this paper an analytical model is presented to describe the physical processes that govern the behaviour of the sensor and determine its sensitivity. The Mi

  16. Development of impedance sensors at ORNL: for measurement of two-phase flows. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Eads, B.G.; Hylton, J.O.

    1979-10-30

    Techniques and equipment have been developed to measure in-vessel local void fraction and velocity in a reflood transient test facility. The two impedance sensors, the flag probe and the string probe, have been tested (prototype sensors) in a variety of air-water and steam-water facilities an in all cases acceptable measurement results were obtained.

  17. Analytic model of a two wire thermal sensor for flow and sound measurements

    NARCIS (Netherlands)

    Honschoten, van J.W.; Krijnen, G.J.M.; Svetovoy, V.B.; Bree, de H.E.; Elwenspoek, M.C.

    2004-01-01

    The Microflown is an acoustic sensor that measures particle velocity instead of pressure, as conventional microphones do. This paper presents an analytical model describing the physical processes that govern the behaviour of the sensor and determine its sensitivity. Forced convection by an acoustic

  18. Length scales in cryogenic injection at supercritical pressure

    Energy Technology Data Exchange (ETDEWEB)

    Branam, R.; Mayer, W. [German Aerospace Center, DLR Lampoldshausen, 74239 Hardthausen (Germany)

    2002-09-01

    Length scales provide some understanding of the injection of cryogenic propellants in rocket chambers on mixing efficiency, which translates to burning efficiency and performance. This project uses supercritical cryogenic nitrogen to look at high-density core flows such as those of coaxial injectors used in rocket engines. The investigation considers test conditions from 4.0 to 6.0 MPa chamber pressure at two injection velocities and temperatures. Experimental data taken by using shadowgraph images provides a means of characterizing turbulent flow structures using a two-point correlation method to determine length scales and structure shapes. The experimental results are compared to computational models. (orig.)

  19. Sensor Fish Characterization of Fish Passage Conditions through John Day Dam Spillbay 20 with a Modified Flow Deflector

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, Joanne P.

    2011-04-29

    Fish passage conditions over a modified deflector in Spillbay 20 at John Day Dam were evaluated by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers (USACE), Portland District, using Sensor Fish devices. The objectives of the study were to describe and compare passage exposure conditions at two spill discharges, 2.4 and 4.0 thousand cubic feet per second (kcfs), identifying potential fish injury regions within the routes, and to evaluate a low-tailwater condition at the 2.4-kcfs discharge. The study was performed in April 2010 concurrent with HI-Z balloon-tag studies by Normandeau Associates, Inc. Sensor Fish data were analyzed to estimate 1) exposure conditions, particularly exposure to severe collision and shear events; 2) differences in passage conditions between treatments; and 3) relationships to live-fish injury and mortality data estimates. Nearly all Sensor Fish significant events were classified as collisions; the most severe occurred at the gate, on the spillbay chute, or at the deflector transition. Collisions in the gate region were observed only during the 2.4-kcfs discharge, when the tainter gate was open 1.2 ft. One shear event was observed during the evaluation, occurring at the deflector transition during passage at the 2.4-kcfs discharge at low tailwater. Flow quality, computed using the Sensor Fish turbulence index, was best for passage at the low-flow low-tailwater condition as well. The worst flow quality was observed for the 4.0-kcfs test condition. Contrasting the passage exposure conditions, the 2.4-kcfs low-tailwater treatment would be most deleterious to fish survival and well-being.

  20. SINGLE: single photon sensitive cryogenic light detectors

    Science.gov (United States)

    Biassoni, Matteo; SINGLE Collaboration

    2017-09-01

    Thermal detectors operated at few mK as calorimeters are a powerful tool for the study of rare particle physics processes. In order to implement particle identification, light detection can be effectively performed by means of other thermal detectors operated as light sensors. This configuration can be used also in large scale, thousand-channels setups, but the light sensors must be sensitive enough to detect few, possibly a single, photons. The SINGLE project described here aims at producing silicon based, large area devices that can be operated as thermal detectors with single-photon sensitivity, and demonstrate the reliability of the performance, scalability of the production process and integrability with present and next generation cryogenic experiments for the search for rare events.

  1. Aerogel Insulation to Support Cryogenic Technologies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA is seeking a high performance thermal insulation material for cryogenic applications in space launch development. Many of the components in cryogenic...

  2. Cryogenic Propellant Storage and Transfer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Cryogenic Propellant Storage and Transfer project will demonstrate the capability to safely and efficiently store, transfer and measure cryogenic propellants,...

  3. Flow injection chemiluminescence sensor based on core-shell magnetic molecularly imprinted nanoparticles for determination of sulfadiazine.

    Science.gov (United States)

    Lu, Fuguang; Li, Huaijiang; Sun, Min; Fan, Lulu; Qiu, Huamin; Li, Xiangjun; Luo, Chuannan

    2012-03-09

    A novel flow injection chemiluminescence (FI-CL) sensor for determination of sulfadiazine (SDZ) using core-shell magnetic molecularly imprinted polymers (MMIPs) as recognition element is developed. Briefly, a hydrophilic MMIPs layer was produced at the surface of Fe(3)O(4)@SiO(2) magnetic nanoparticles (MNPs) via combination of molecular imprinting and reversible stimuli responsive hydrogel. And it provided the MMIPs with excellent adsorption capacity and rapid adsorption rate due to the imprinted sites mostly situated on the surface of MMIPs. Then the prepared SDZ-MMIPs were packed into flow cell to establish a novel FI-CL sensor. The sensor provided a wide linear range for SDZ of 4.0×10(-7) to 1.0×10(-4) mol L(-1) with a detection limit of 1.54×10(-7) mol L(-1). And the relative standard deviation (RSD) for the determination of 1.0×10(-6) mol L(-1) SDZ was 2.56% (n=11). The proposed method was applied to determine SDZ in urine samples and satisfactory results were obtained.

  4. A dynamic response model for pressure sensors in continuum and high Knudsen number flows with large temperature gradients

    Science.gov (United States)

    Whitmore, Stephen A.; Petersen, Brian J.; Scott, David D.

    1996-01-01

    This paper develops a dynamic model for pressure sensors in continuum and rarefied flows with longitudinal temperature gradients. The model was developed from the unsteady Navier-Stokes momentum, energy, and continuity equations and was linearized using small perturbations. The energy equation was decoupled from momentum and continuity assuming a polytropic flow process. Rarefied flow conditions were accounted for using a slip flow boundary condition at the tubing wall. The equations were radially averaged and solved assuming gas properties remain constant along a small tubing element. This fundamental solution was used as a building block for arbitrary geometries where fluid properties may also vary longitudinally in the tube. The problem was solved recursively starting at the transducer and working upstream in the tube. Dynamic frequency response tests were performed for continuum flow conditions in the presence of temperature gradients. These tests validated the recursive formulation of the model. Model steady-state behavior was analyzed using the final value theorem. Tests were performed for rarefied flow conditions and compared to the model steady-state response to evaluate the regime of applicability. Model comparisons were excellent for Knudsen numbers up to 0.6. Beyond this point, molecular affects caused model analyses to become inaccurate.

  5. Cryogenic Liquid Sample Acquisition System for Remote Space Applications

    Science.gov (United States)

    Mahaffy, Paul; Trainer, Melissa; Wegel, Don; Hawk, Douglas; Melek, Tony; Johnson, Christopher; Amato, Michael; Galloway, John

    2013-01-01

    There is a need to acquire autonomously cryogenic hydrocarbon liquid sample from remote planetary locations such as the lakes of Titan for instruments such as mass spectrometers. There are several problems that had to be solved relative to collecting the right amount of cryogenic liquid sample into a warmer spacecraft, such as not allowing the sample to boil off or fractionate too early; controlling the intermediate and final pressures within carefully designed volumes; designing for various particulates and viscosities; designing to thermal, mass, and power-limited spacecraft interfaces; and reducing risk. Prior art inlets for similar instruments in spaceflight were designed primarily for atmospheric gas sampling and are not useful for this front-end application. These cryogenic liquid sample acquisition system designs for remote space applications allow for remote, autonomous, controlled sample collections of a range of challenging cryogenic sample types. The design can control the size of the sample, prevent fractionation, control pressures at various stages, and allow for various liquid sample levels. It is capable of collecting repeated samples autonomously in difficult lowtemperature conditions often found in planetary missions. It is capable of collecting samples for use by instruments from difficult sample types such as cryogenic hydrocarbon (methane, ethane, and propane) mixtures with solid particulates such as found on Titan. The design with a warm actuated valve is compatible with various spacecraft thermal and structural interfaces. The design uses controlled volumes, heaters, inlet and vent tubes, a cryogenic valve seat, inlet screens, temperature and cryogenic liquid sensors, seals, and vents to accomplish its task.

  6. Terahertz Quantum Cascade Laser-Based Sensors for Hypersonic Flows (7275-020) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to design, build, test, and deliver to NASA a THz wavelength absorption sensor for continuous monitoring of atomic oxygen...

  7. Towards an Automatic Parking System using Bio-Inspired 1-D Optical Flow Sensors

    OpenAIRE

    2015-01-01

    International audience; Although several (semi-) automatic parking systems have been presented throughout the years [1]–[12], car manufacturers are still looking for low-cost sensors providing redundant information about the obstacles around the vehicle, as well as efficient methods of processing this information, in the hope of achieving a very high level of robustness. We therefore investigated how Local Motion Sensors (LMSs) [13], [14], comprising only of a few pixels giving 1-D optical fl...

  8. Optimization of Cricket-inspired, Biomimetic Artificial Hair Sensors for Flow Sensing

    CERN Document Server

    Izadi, N; Floris, J; Krijnen, G

    2008-01-01

    High density arrays of artificial hair sensors, biomimicking the extremely sensitive mechanoreceptive filiform hairs found on cerci of crickets have been fabricated successfully. We assess the sensitivity of these artificial sensors and present a scheme for further optimization addressing the deteriorating effects of stress in the structures. We show that, by removing a portion of chromium electrodes close to the torsional beams, the upward lift at the edges of the membrane due to the stress, will decrease hence increase the sensitivity.

  9. Segmented wind energy harvester based on contact-electrification and as a self-powered flow rate sensor

    Science.gov (United States)

    Su, Yuanjie; Xie, Guangzhong; Xie, Fabiao; Xie, Tao; Zhang, Qiuping; Zhang, Hulin; Du, Hongfei; Du, Xiaosong; Jiang, Yadong

    2016-06-01

    A single-electrode-based segmented triboelectric nanogenerator (S-TENG) was developed. By utilizing the wind-induced vibration of a fluorinated ethylene propylene (FEP) film between two copper electrodes, the S-TENG delivers an open-circuit voltage up to 36 V and a short-circuit current of 11.8 μA, which can simultaneously light up 20 LEDs and charge capacitors. Moreover, the S-TENG holds linearity between output current and flow rate, revealing its feasibility as a self-powered wind speed sensor. This work demonstrates potential applications of S-TENG in wind energy harvester, self-powered gas sensor, high altitude air navigation.

  10. Highly spatially resolved velocity measurements of a turbulent channel flow by a fiber-optic heterodyne laser-Doppler velocity-profile sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shirai, K.; Pfister, T.; Buettner, L.; Czarske, J. [Dresden University of Technology (TU Dresden), Department of Electrical Engineering and Information Technology, Chair for Measurement and Testing Techniques, Dresden (Germany); Mueller, H. [Physikalisch-Technische Bundesanstalt Braunschweig (PTB), Department 1.4 Gas Flow, Braunschweig (Germany); Becker, S.; Lienhart, H.; Durst, F. [Institute of Fluid Mechanics (LSTM), Friedrich-Alexander-University Erlangen-Nuernberg, Erlangen (Germany)

    2006-03-15

    Velocity measurements with a high spatial resolution are important in turbulent flow research. In this paper, we report on the development of a new fiber-optic laser-Doppler velocity-profile sensor exhibiting a spatial resolution of up to 5 {mu}m and its application to turbulent boundary layers. The sensor developed in the present work employs a frequency-division-multiplexing technique in order to separate two measurement signals from the two fringe systems. Velocity measurements close to zero at the solid wall were realized using heterodyne technique. The use of fiber optics improved a robustness of the sensor. The measurement accuracy of the sensor was experimentally investigated with respect to the spatial resolution and velocity. Universal velocity profile of a turbulent flow was obtained in a fully developed channel flow. Mean and fluctuating velocity are presented with a high spatial resolution. (orig.)

  11. Expandable Purge Chambers Would Protect Cryogenic Fittings

    Science.gov (United States)

    Townsend, Ivan I., III

    2004-01-01

    Expandable ice-prevention and cleanliness-preservation (EIP-CP) chambers have been proposed to prevent the accumulation of ice or airborne particles on quick-disconnect (QD) fittings, or on ducts or tubes that contain cryogenic fluids. In the original application for which the EIP-CP chambers were conceived, there is a requirement to be able to disconnect and reconnect the QD fittings in rapid succession. If ice were to form on the fittings by condensation and freezing of airborne water vapor on the cold fitting surfaces, the ice could interfere with proper mating of the fittings, making it necessary to wait an unacceptably long time for the ice to thaw before attempting reconnection. By keeping water vapor away from the cold fitting surfaces, the EIP-CP chambers would prevent accumulation of ice, preserving the ability to reconnect as soon as required. Basically, the role of an EIP-CP chamber would be to serve as an enclosure for a flow of dry nitrogen gas that would keep ambient air away from QD cryogenic fittings. An EIP-CP chamber would be an inflatable device made of a fabriclike material. The chamber would be attached to an umbilical plate holding a cryogenic QD fitting.

  12. Minimalistic optic flow sensors applied to indoor and outdoor visual guidance and odometry on a car-like robot.

    Science.gov (United States)

    Mafrica, Stefano; Servel, Alain; Ruffier, Franck

    2016-11-10

    Here we present a novel bio-inspired optic flow (OF) sensor and its application to visual  guidance and odometry on a low-cost car-like robot called BioCarBot. The minimalistic OF sensor was robust to high-dynamic-range lighting conditions and to various visual patterns encountered thanks to its M(2)APIX auto-adaptive pixels and the new cross-correlation OF algorithm implemented. The low-cost car-like robot estimated its velocity and steering angle, and therefore its position and orientation, via an extended Kalman filter (EKF) using only two downward-facing OF sensors and the Ackerman steering model. Indoor and outdoor experiments were carried out in which the robot was driven in the closed-loop mode based on the velocity and steering angle estimates. The experimental results obtained show that our novel OF sensor can deliver high-frequency measurements ([Formula: see text]) in a wide OF range (1.5-[Formula: see text]) and in a 7-decade high-dynamic light level range. The OF resolution was constant and could be adjusted as required (up to [Formula: see text]), and the OF precision obtained was relatively high (standard deviation of [Formula: see text] with an average OF of [Formula: see text], under the most demanding lighting conditions). An EKF-based algorithm gave the robot's position and orientation with a relatively high accuracy (maximum errors outdoors at a very low light level: [Formula: see text] and [Formula: see text] over about [Formula: see text] and [Formula: see text]) despite the low-resolution control systems of the steering servo and the DC motor, as well as a simplified model identification and calibration. Finally, the minimalistic OF-based odometry results were compared to those obtained using measurements based on an inertial measurement unit (IMU) and a motor's speed sensor.

  13. Passenger flow statistics across the field of view based on the depth map of the double Xtion sensors

    Science.gov (United States)

    Yin, Zhang-qin; Gu, Guo-hua; Bai, Xiao-feng; Zhao, Tie-kun; Chen, Hai-xin

    2013-08-01

    It introduces a new method to achieve the passenger flow statistics in stereo vision according to the original depth image output by the monocular Xtion sensor, aiming at the problem of algorithm with large amounts of data and realization of single field with dual camera on the basis of stereo vision. Double Xtion sensors are used to expand the range of view angle because of the monocular Xtion sensor's limitations, whose view range is 45°*58° with small transverse view range and can't meet the passenger flow statistics. Due to the characteristics of constant physical space dimensions, use the improved SIFT (Scale Invariant Features Transform) feature algorithm to realize the auto - stereoscopic splice of binocular original depth images. Firstly, the feature points of the reference image (the image to be matched) and the subsequent image (the image to be matched with the reference image) are obtained by SIFT algorithm, getting the location, scale and direction of the feature points and the feature points are described by means of the 128-dimensional vector .Secondly, complete the match of the feature points of the two images to calculate overlapping area, using the nearest neighbor method. Finally, image stitching is completed based on multi-resolution wavelet transform, which contains three-dimensional spatial information of the human body, thus use a method to analysis comprehensively the depth image for field detection and tracking based on the features such as the head shape, the head area the spatial position relation of the human head and shoulder and so on. The experimental results show that this method not only improve the detection accuracy and efficiency, reduce the amount of operation data, so that the system is simple in structure, but also solve many problems of passenger flow statistics based on video stream in the system, accuracy up to 93%, having high and practical application value.

  14. Characteristics of a micro-mechanical thermal flow sensor based on a two hot wires principle with constant temperature operation in a small channel

    Science.gov (United States)

    Lange, P.; Weiss, M.; Warnat, S.

    2014-12-01

    A thermal mass flow sensor with high dynamic flow range in silicon bulk micromachining membrane technology is presented. The response behavior of this sensor based on a two hot wire principle is described. This sensor configuration uses two hot wires mounted closely spaced one behind the other within a thin membrane, kept at the same temperature. The power to compensate cooling of and the interaction between the two hot wires are used to calculate mass flows and directionality of flows of gaseous and liquid fluids in a small channel. The response shows both anemometric and calorimetric behavior, depending on fluid, channel height and flow range. The hot wires are heated relative to temperature sensors located also on an isolated membrane on the same chip. Choosing an appropriate evaluation procedure an independence of the signal from the ambient temperature is achieved. This configuration will be discussed in view of the published results of single heater flow sensors, being of calorimetric or anemometric type. A calculation method for the determination of linear and power law range of the response is given.

  15. Towards cryogenic liquid –vapor energy storage units for space applications

    OpenAIRE

    Afonso, Josiana Prado

    2013-01-01

    Dissertation to obtain the Doctoral degree in Physics Engineering With the development of mechanical coolers and very sensitive cryogenic sensors, it could be interesting to use Energy Storage Units (ESU) and turn off the cryocooler to operate in a free micro vibration environment. An ESU would also avoid cryogenic systems oversized to attenuate temperature fluctuations due to thermal load variations which is useful particularly for space applications. In both cases, the temperature dri...

  16. Accurate measurement of air supply. Radial blower with a mass flow sensor; Fuer eine exakte Luftzuteilung. Radialgeblaese mit Massenstromsensor

    Energy Technology Data Exchange (ETDEWEB)

    Hartauer, Siegbert [ebm-papst Landshut GmbH, Landshut (Germany)

    2009-07-01

    Fire is alive, which has always made it an interesting object for interior decoration, e.g. open chimneys or chimneys with glass windows. Modern gas-fuelled chimneys combine the soothing vision of open flames with efficient room heating. For low pollution and low consumption, fire needs fuel and oxygen in an optimum ratio. Conventional ''atmospheric'' burners must be adjusted on site, but variations of temperature and atmospheric pressure will still vary the air supply. As an optimum alternative, the contribution presents a new radial blower with an integrated mass flow sensor. (orig.)

  17. Cryogenic Piezoelectric Actuator

    Science.gov (United States)

    Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.

    2009-01-01

    In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

  18. Effect of Electron Drag on Performances of Carbon Nanotubes as Flow Sensors

    Institute of Scientific and Technical Information of China (English)

    L(ü) Jian-wei; WANG Wan-lu; LIAO Ke-jun; CAO Chun-lan; LIU Cang-lin; ZENG Qing-gao

    2004-01-01

    Experimentally, the electron drag effect on carbon nanotube surface in flowing liquids was investigated. It was found that electric current could be generated in metallic carbon nanotubes immersed in the liquids. Carbon nanotubes were synthesized on Si substrate by hot filament chemical vapor deposition. The experimental results showed that the flow-induced current on the surface of carbon nanotube films was closely depended on the flow rate, concentration, properties and temperature of liquids. The flow-induced current was increased with the increasing of flow rate, concentration and temperature of liquids. The obtained results were discussed in detail.

  19. Cryogenic capability for equation-of-state measurements on the Sandia Z pulsed radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, D.L.; Johnston, R.R.; Asay, J.R.

    1998-02-01

    Experimental cryogenic capabilities are essential for the study of ICF high-gain target and weapons effects issues involving dynamic materials response at low temperatures. The authors are developing a general purpose cryogenic target system for precision radiation driven EOS and shock physics experiments at liquid helium temperatures on the Sandia Z pulsed radiation source. Cryogenic sample cooling in the range of 6--30 K is provided by a liquid helium cryostat and an active temperature control system. The cryogenic target assembly is capable of condensing liquid deuterium samples from the gas phase at about 20 K, as well as cooling solid samples such as beryllium and CH ablators for ICF. The target assembly will also include the capability to use various shock diagnostics, such as VISAR interferometry and fiber-optic-coupled shock breakout diagnostics. They are characterizing the thermal and optical performance of the system components in an off-line cryogenic test facility and have designed an interface to introduce the cryogenic transfer lines, gas lines, and sensor cables into the Z vacuum section. Survivability of high-value cryogenic components in the destructive post-implosion environment of Z is a major issue driving the design of this cryogenic target system.

  20. Heat dissipation sensors of variable length for the measurement of sap flow in trees with deep sapwood.

    Science.gov (United States)

    James, Shelley A; Clearwater, Michael J; Meinzer, Frederick C; Goldstein, Guillermo

    2002-03-01

    Robust thermal dissipation sensors of variable length (3 to 30 cm) were developed to overcome limitations to the measurement of radial profiles of sap flow in large-diameter tropical trees with deep sapwood. The effective measuring length of the custom-made sensors was reduced to 1 cm at the tip of a thermally nonconducting shaft, thereby minimizing the influence of nonuniform sap flux density profiles across the sapwood. Sap flow was measured at different depths and circumferential positions in the trunks of four trees at the Parque Natural Metropolitano canopy crane site, Panama City, Republic of Panama. Sap flow was detected to a depth of 24 cm in the trunks of a 1-m-diameter Anacardium excelsum (Bertero & Balb. ex Kunth) Skeels tree and a 0.65-m-diameter Ficus insipida Willd. tree, and to depths of 7 cm in a 0.34-m-diameter Cordia alliodora (Ruiz & Pav.) Cham. trunk, and 17 cm in a 0.47-m-diameter Schefflera morototoni (Aubl.) Maguire, Steyerm. & Frodin trunk. Sap flux density was maximal in the outermost 4 cm of sapwood and declined with increasing sapwood depth. Considerable variation in sap flux density profiles was observed both within and among the trees. In S. morototoni, radial variation in sap flux density was associated with radial variation in wood properties, particularly vessel lumen area and distribution. High variability in radial and circumferential sap flux density resulted in large errors when measurements of sap flow at a single depth, or a single radial profile, were used to estimate whole-plant water use. Diurnal water use ranged from 750 kg H2O day-1 for A. excelsum to 37 kg H2O day-1 for C. alliodora.

  1. Low-complexity wireless communication modeling for information flow control in sensor networks

    NARCIS (Netherlands)

    Foeken, E. van; Kwakkernaat, M.R.J.A.E.

    2011-01-01

    The increasing demand for shared awareness in multi-platform sensor systems requires advanced wireless information sharing techniques. The analysis of these techniques requires information about communication resources and latency to be available in models. The work presented here introduces generic

  2. Development of Acid Resistance Velocity Sensor for Analyzing Acidic Fluid Flow Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gyujin; Yoon, Jinwon; Yu, Sangseok [Chungnam Nat’l Univ., Daejeon (Korea, Republic of)

    2016-10-15

    This study presents the development of an acid resistance velocity sensor that is used for measuring velocity inside a copper sulfate plating bath. First, researchers investigated the acid resistance coating to confirm the suitability of the anti-acid sensor in a very corrosive environment. Then, researchers applied signal processing methods to reduce noise and amplify the signal. Next, researchers applied a pressure-resistive sensor with an operation amplifier (Op Amp) and low-pass filter with high impedance to match the output voltage of a commercial flowmeter. Lastly, this study compared three low-pass filters (Bessel, Butterworth and Chebyshev) to select the appropriate signal process circuit. The results show 0.0128, 0.0023, and 5.06% of the mean square error, respectively. The Butterworth filter yielded more precise results when compared to a commercial flowmeter. The acid resistive sensor is capable of measuring velocities ranging from 2 to 6 m/s with a 2.7% margin of error.

  3. Low-complexity wireless communication modeling for information flow control in sensor networks

    NARCIS (Netherlands)

    Foeken, E. van; Kwakkernaat, M.R.J.A.E.

    2011-01-01

    The increasing demand for shared awareness in multi-platform sensor systems requires advanced wireless information sharing techniques. The analysis of these techniques requires information about communication resources and latency to be available in models. The work presented here introduces generic

  4. Nanodielectrics for Cryogenic Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tuncer, Enis [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Pace, Marshall O [ORNL; More, Karren [Oak Ridge National Laboratory (ORNL); Sathyamurthy, Srivatsan [University of Tennessee, Knoxville (UTK); Woodward, Jonathan [ORNL; Rondinone, Adam Justin [ORNL

    2009-01-01

    In this paper we report the recent advances in nanodielectrics that were developed and tested for cryogenic dielectric applications. The systems studied are composed of nanometer size particles. Particles were produced using either an ex-situ or in-situ technique. It is observed that there are clear differences in the structural properties of materials produced using these two approaches. Either no significant degradation or improvement in the electrical insulation properties were observed for ex-situ nano-particle samples processed with an ultrasonic processor and in-situ nano-particle samples. Nanodielectrics have the potential to be tailored with better thermal and mechanical properties without losing their electrical insulation characteristics.

  5. Cryogenic Cam Butterfly Valve

    Science.gov (United States)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  6. Identification of two-phase flow regimes under variable gravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kamiel S Gabriel [University of Ontario Institute of Technology 2000 Simcoe Street North, Oshawa, ON L1H 7K4 (Canada); Huawei Han [Mechanical Engineering Department, University of Saskatchewan 57 Campus Dr., Saskatoon, Saskatchewan, S7N 5A9 (Canada)

    2005-07-01

    Full text of publication follows: Two-phase flow is becoming increasingly important as we move into new and more aggressive technologies in the twenty-first century. Some of its many applications include the design of efficient heat transport systems, the transfer and storage of cryogenic fluids, and condensation and flow boiling processes in heat exchangers and energy transport systems. Two-phase flow has many applications in reduced gravity environments experienced in orbiting spacecraft and earth observation satellites. Examples are heat transport systems, the transfer and storage of cryogenic fluids, and condensation and flow boiling processes in heat exchangers. A concave parallel plate capacitance sensor has been developed to measure void fraction for the purpose of objectively identifying flow regimes. The sensor has been used to collect void-fraction data at microgravity conditions aboard the NASA and ESA zero-gravity aircraft. It is shown that the flow regimes can be objectively determined from the probability density functions of the void fraction signals. It was shown that under microgravity conditions four flow regimes exist: bubbly flow, characterized by discrete gas bubbles flowing in the liquid; slug flow, consisting of Taylor bubbles separated by liquid slugs which may or may not contain several small gas bubbles; transitional flow, characterized by the liquid flowing as a film at the tube wall, and the gas phase flowing in the center with the frequent appearance of chaotic, unstable slugs; and annular flow in which the liquid flows as a film along the tube wall and the gas flows uninterrupted through the center. Since many two-phase flow models are flow regime dependent, a method that can accurately and objectively determine flow regimes is required. (authors)

  7. Cooperative Suction by Vertical Capillary Array Pump for Controlling Flow Profiles of Microfluidic Sensor Chips

    Directory of Open Access Journals (Sweden)

    Emi Tamechika

    2012-10-01

    Full Text Available A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary.

  8. Cryogenic instrumentation for ITER magnets

    Science.gov (United States)

    Poncet, J.-M.; Manzagol, J.; Attard, A.; André, J.; Bizel-Bizellot, L.; Bonnay, P.; Ercolani, E.; Luchier, N.; Girard, A.; Clayton, N.; Devred, A.; Huygen, S.; Journeaux, J.-Y.

    2017-02-01

    Accurate measurements of the helium flowrate and of the temperature of the ITER magnets is of fundamental importance to make sure that the magnets operate under well controlled and reliable conditions, and to allow suitable helium flow distribution in the magnets through the helium piping. Therefore, the temperature and flow rate measurements shall be reliable and accurate. In this paper, we present the thermometric chains as well as the venturi flow meters installed in the ITER magnets and their helium piping. The presented thermometric block design is based on the design developed by CERN for the LHC, which has been further optimized via thermal simulations carried out by CEA. The electronic part of the thermometric chain was entirely developed by the CEA and will be presented in detail: it is based on a lock-in measurement and small signal amplification, and also provides a web interface and software to an industrial PLC. This measuring device provides a reliable, accurate, electromagnetically immune, and fast (up to 100 Hz bandwidth) system for resistive temperature sensors between a few ohms to 100 kΩ. The flowmeters (venturi type) which make up part of the helium mass flow measurement chain have been completely designed, and manufacturing is on-going. The behaviour of the helium gas has been studied in detailed thanks to ANSYS CFX software in order to obtain the same differential pressure for all types of flowmeters. Measurement uncertainties have been estimated and the influence of input parameters has been studied. Mechanical calculations have been performed to guarantee the mechanical strength of the venturis required for pressure equipment operating in nuclear environment. In order to complete the helium mass flow measurement chain, different technologies of absolute and differential pressure sensors have been tested in an applied magnetic field to identify equipment compatible with the ITER environment.

  9. Advanced ACTPol Cryogenic Detector Arrays and Readout

    Science.gov (United States)

    Henderson, S. W.; Allison, R.; Austermann, J.; Baildon, T.; Battaglia, N.; Beall, J. A.; Becker, D.; De Bernardis, F.; Bond, J. R.; Calabrese, E.; Choi, S. K.; Coughlin, K. P.; Crowley, K. T.; Datta, R.; Devlin, M. J.; Duff, S. M.; Dunkley, J.; Dünner, R.; van Engelen, A.; Gallardo, P. A.; Grace, E.; Hasselfield, M.; Hills, F.; Hilton, G. C.; Hincks, A. D.; Hloẑek, R.; Ho, S. P.; Hubmayr, J.; Huffenberger, K.; Hughes, J. P.; Irwin, K. D.; Koopman, B. J.; Kosowsky, A. B.; Li, D.; McMahon, J.; Munson, C.; Nati, F.; Newburgh, L.; Niemack, M. D.; Niraula, P.; Page, L. A.; Pappas, C. G.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Sehgal, N.; Sherwin, B. D.; Sievers, J. L.; Simon, S. M.; Spergel, D. N.; Staggs, S. T.; Stevens, J. R.; Thornton, R.; Van Lanen, J.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-08-01

    Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope, adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28-230 GHz). Its maps of primary and secondary cosmic microwave background anisotropies—imaged in intensity and polarization at few arcminute-scale resolution—will enable precision cosmological constraints and also a wide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the Advanced ACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new multiplexing readout architecture which uses superconducting quantum interference devices and time division to achieve a 64-row multiplexing factor. Here we present the status and scientific goals of the Advanced ACTPol instrument, emphasizing the design and implementation of the Advanced ACTPol cryogenic detector arrays.

  10. Power control electronics for cryogenic instrumentation

    Science.gov (United States)

    Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.

    1995-01-01

    In order to achieve a high-efficiency high-density cryogenic instrumentation system, the power processing electronics should be placed in the cold environment along with the sensors and signal-processing electronics. The typical instrumentation system requires low voltage dc usually obtained from processing line frequency ac power. Switch-mode power conversion topologies such as forward, flyback, push-pull, and half-bridge are used for high-efficiency power processing using pulse-width modulation (PWM) or resonant control. This paper presents several PWM and multiresonant power control circuits, implemented using commercially available CMOS and BiCMOS integrated circuits, and their performance at liquid-nitrogen temperature (77 K) as compared to their room temperature (300 K) performance. The operation of integrated circuits at cryogenic temperatures results in an improved performance in terms of increased speed, reduced latch-up susceptibility, reduced leakage current, and reduced thermal noise. However, the switching noise increased at 77 K compared to 300 K. The power control circuits tested in the laboratory did successfully restart at 77 K.

  11. Cryogenic Silicon Microstrip Detector Modules for LHC

    CERN Document Server

    Perea-Solano, B

    2004-01-01

    CERN is presently constructing the LHC, which will produce collisions of 7 TeV protons in 4 interaction points at a design luminosity of 1034 cm-2 s-1. The radiation dose resulting from the operation at high luminosity will cause a serious deterioration of the silicon tracker performance. The state-of-art silicon microstrip detectors can tolerate a fluence of about 3 1014 cm-2 of hadrons or charged leptons. This is insufficient, however, for long-term operation in the central parts of the LHC trackers, in particular after the possible luminosity upgrade of the LHC. By operating the detectors at cryogenic temperatures the radiation hardness can be improved by a factor 10. This work proposes a cryogenic microstrip detector module concept which has the features required for the microstrip trackers of the upgraded LHC experiments at CERN. The module can hold an edgeless sensor, being a good candidate for improved luminosity and total cross-section measurements in the ATLAS, CMS and TOTEM experiments. The design o...

  12. Calibration system for cryogenic temperature sensors based on G-M cryocooler%基于G-M低温制冷机的低温温度计标定系统

    Institute of Scientific and Technical Information of China (English)

    翁捷敏; 黄永华

    2013-01-01

    设计和搭建了一套5.2-300K温区的温度计标定系统,以G-M制冷机为冷源,进口已标定温度计为定标源,对Cernox负温度系数温度计、硅二极管温度计、PT100铂电阻温度计等进行了标定,获得了其温度特性曲线并进行对比,分析了标定误差,发现该系统具有较高的标定精度,所标定的温度计在其有效温区内能达到±15mK以内的不确定度,与定标源温度计处于同等量级.%A calibration system for temperature sensors between 5. 2K and 300K was established. A G - M cryocooler was used as the cold source and a commercial calibrated temperature sensor was used as the reference. One Cernox NTC temperature sensor, two silicon diode temperature sensors and five PT100 platinum resistance temperature sensors were calibrated. The response curves of these sensors were acquired. The uncertainty of the calibration system for all the above sample sensors was estimated to be within ± 15mK in their working range, which is on the same magnitude as the reference sensor.

  13. Cryogenic Acoustic Suppression Testing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed project will explore and test the feasibility and effectiveness of using a cryogenic fluid (liquid nitrogen) to facilitate acoustic suppression in a...

  14. Lightweight Inflatable Cryogenic Tank Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of an inflatable and lightweight polymer-fabric structured pressure vessel designed for the containment of cryogenic fluids....

  15. Cryogenic Systems and Superconductive Power

    Science.gov (United States)

    The report defines, investigates, and experimentally evaluates the key elements of a representative crogenic turborefrigerator subsystem suitable for providing reliable long-lived cryogenic refrigeration for a superconductive ship propulsion system.

  16. Ultrasensitive flow sensing of a single cell using graphene-based optical sensors.

    Science.gov (United States)

    Xing, Fei; Meng, Gui-Xian; Zhang, Qian; Pan, Lei-Ting; Wang, Peng; Liu, Zhi-Bo; Jiang, Wen-Shuai; Chen, Yongsheng; Tian, Jian-Guo

    2014-06-11

    On the basis of the polarization-dependent absorption of graphene under total internal reflection, we designed a graphene-based optical refractive index sensor with high resolution of 1.7 × 10(-8) and sensitivity of 4.3 × 10(7) mV/RIU, as well as an extensive dynamic range. This highly sensitive graphene optical sensor enables label-free, live-cell, and highly accurate detection of a small quantity of cancer cells among normal cells at the single-cell level and the simultaneous detection and distinction of two cell lines without separation. It provides an accurate statistical distribution of normal and cancer cells with fewer cells. This facile and highly sensitive sensing refractive index may expand the practical applications of the biosensor.

  17. Design of New Ultrasonic Flow Sensor%一种新型超声波流量传感器

    Institute of Scientific and Technical Information of China (English)

    李艳

    2012-01-01

    介绍了以AT89C52单片机为核心,以CD4049串并联组合及超声波发射换能器TCT40 - 10F1构成超声波发射电路,以CX20106A红外集成电路为核心构成超声波接收电路,采用C语言编程的超声波测流量系统.系统由电源、超声波发射装置、超声波接收装置、键盘输入、流量显示、报警装置、通信设备等组成.采用了速差法测流量的原理,从而消除了温度对测量结果的影响.同时采用一发一收双传感器的测量方案,降低了传感器肓区对测量精度的影响,提高了超声波测量的精度和可靠性.%This paper introduced a new ultrasonic flow sensor,which took AT89C52 microcontroller as the core,CD4049 and ultrasonic transmitting transducer,TCT40 - 10F1 .constituted the transmitter circuit,and took CX20106A as the ultrasonic receiver circuit, used C language as the programming languages. The system consisted of power supply, ultrasonic emission devices, ultrasonic sensors,keyboard,flow display,alarm devices,communications equipment and other components. Speed difference method was used to measure the flow,so it can eliminate the effect of temperature on measurements. It used one sending one receiving measurement program, reduced the effect of blind spot on measuring accuracy and increased accuracy reliability.

  18. A 3D CFD Simulation and Analysis of Flow-Induced Forces on Polymer Piezoelectric Sensors in a Chinese Liquors Identification E-Nose.

    Science.gov (United States)

    Gu, Yu; Wang, Yang-Fu; Li, Qiang; Liu, Zu-Wu

    2016-10-20

    Chinese liquors can be classified according to their flavor types. Accurate identification of Chinese liquor flavors is not always possible through professional sommeliers' subjective assessment. A novel polymer piezoelectric sensor electric nose (e-nose) can be applied to distinguish Chinese liquors because of its excellent ability in imitating human senses by using sensor arrays and pattern recognition systems. The sensor, based on the quartz crystal microbalance (QCM) principle is comprised of a quartz piezoelectric crystal plate sandwiched between two specific gas-sensitive polymer coatings. Chinese liquors are identified by obtaining the resonance frequency value changes of each sensor using the e-nose. However, the QCM principle failed to completely account for a particular phenomenon: we found that the resonance frequency values fluctuated in the stable state. For better understanding the phenomenon, a 3D Computational Fluid Dynamics (CFD) simulation using the finite volume method is employed to study the influence of the flow-induced forces to the resonance frequency fluctuation of each sensor in the sensor box. A dedicated procedure was developed for modeling the flow of volatile gas from Chinese liquors in a realistic scenario to give reasonably good results with fair accuracy. The flow-induced forces on the sensors are displayed from the perspective of their spatial-temporal and probability density distributions. To evaluate the influence of the fluctuation of the flow-induced forces on each sensor and ensure the serviceability of the e-nose, the standard deviation of resonance frequency value (SDF) and the standard deviation of resultant forces (SDFy) in y-direction (Fy) are compared. Results show that the fluctuations of Fy are bound up with the resonance frequency values fluctuations. To ensure that the sensor's resonance frequency values are steady and only fluctuate slightly, in order to improve the identification accuracy of Chinese liquors using

  19. A Complete Optical Sensor System Based on a POF-SPR Platform and a Thermo-Stabilized Flow Cell for Biochemical Applications.

    Science.gov (United States)

    Cennamo, Nunzio; Chiavaioli, Francesco; Trono, Cosimo; Tombelli, Sara; Giannetti, Ambra; Baldini, Francesco; Zeni, Luigi

    2016-02-04

    An optical sensor platform based on surface plasmon resonance (SPR) in a plastic optical fiber (POF) integrated into a thermo-stabilized flow cell for biochemical sensing applications is proposed. This device has been realized and experimentally tested by using a classic receptor-analyte assay. For this purpose, the gold surface of the POF was chemically modified through the formation of a self-assembling monolayer. The surface robustness of the POF-SPR platform has been tested for the first time thanks to the flow cell. The experimental results show that the proposed device can be successfully used for label-free biochemical sensing. The final goal of this work is to achieve a complete, small-size, simple to use and low cost optical sensor system. The whole system with the flow cell and the optical sensor are extensively described, together with the experimental results obtained with an immunoglobulin G (IgG)/anti-IgG assay.

  20. A Complete Optical Sensor System Based on a POF-SPR Platform and a Thermo-Stabilized Flow Cell for Biochemical Applications

    Directory of Open Access Journals (Sweden)

    Nunzio Cennamo

    2016-02-01

    Full Text Available An optical sensor platform based on surface plasmon resonance (SPR in a plastic optical fiber (POF integrated into a thermo-stabilized flow cell for biochemical sensing applications is proposed. This device has been realized and experimentally tested by using a classic receptor-analyte assay. For this purpose, the gold surface of the POF was chemically modified through the formation of a self-assembling monolayer. The surface robustness of the POF-SPR platform has been tested for the first time thanks to the flow cell. The experimental results show that the proposed device can be successfully used for label-free biochemical sensing. The final goal of this work is to achieve a complete, small-size, simple to use and low cost optical sensor system. The whole system with the flow cell and the optical sensor are extensively described, together with the experimental results obtained with an immunoglobulin G (IgG/anti-IgG assay.

  1. Quality Assurance of LHC Cryogenic Instrumentation during Installation and Commissioning

    CERN Document Server

    Lopez Lorente, A; Casas-Cubillos, J; Fortescue, E; Gomes, P; Jeanmonod, N; Peñacoba, G; Vauthier, N

    2009-01-01

    The operation and monitoring of the LHC requires a cryogenic instrumentation system of an unprecedented size (800 instrumentation crates, holding 15000 sensors and actuators), with strict constraints on temperature measurement uncertainty and radiation hardness for all sensors and actuators. This paper presents the applied procedures of quality assurance and the specific hard- & software tools used to meet and track the mentioned requirements during its lifetime (fabrication, installation, commissioning, operation and maintenance); within the given constraints of time schedule, accessibility and coordination with other teams.

  2. Real time, Non-intrusive Detection of Liquid Nitrogen in Liquid Oxygen (LOX) at High Pressure and High Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SSC needs the sensors that are capable and can be operated in liquid oxygen (LOX) and or liquid hydrogen (LH2) cryogenic environment to improve SSC cryogenic...

  3. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  4. Design and fabrication of a metal core PVDF fiber for an air flow sensor

    Science.gov (United States)

    Bian, Yixiang; Liu, Rongrong; Huang, Xiaomei; Hong, Jin; Huang, Huiyu; Hui, Shen

    2015-10-01

    To track prey or avoid predators, many arthropods can detect variations in airflow and pressure gradients using an array of very thin and sensitive filiform hairs. In this study, metal core piezoelectric poly(vinylidene fluoride) (PVDF) fibers were prepared to mimic such hair sensors. The flexibility of the fibers was very good, which was helpful for overcoming the typical brittleness of piezoelectric ceramic fibers. At the same time, the diameter of the fibers was very small (down to 50 μm in diameter). In order to mimic the insects’ hairs to the maximum extent, which was expected to greatly improve the sensitivity of such PVDF fiber-based sensors, a feasible process to prepare and extract electrodes on the surface of the fibers had to be developed. Compared with stainless steel filament-core fibers, the molybdenum filament-core PVDF fibers were easy to stretch. The molybdenum filament was then covered by a cylindrical PVDF layer with a diameter of 400 μm. One half of the longitudinal surface of the fibers was spray-coated with a conductive silver adhesive. The metal core was then used as one electrode, and the conductive silver adhesive was used as the other electrode. After polarization, a single metal-core PVDF fiber could be used as an airflow sensor. The surface structure and the sections of the PVDF fiber were analyzed by scanning electron microscopy. The results of the mechanical stretching tests showed that the metal core greatly enhanced the mechanical properties of the PVDF fibers. X-ray diffraction revealed that the greater the stretching ratio, the higher the α-to-β-phase conversion rate during the preparation of the PVDF fibers. A single metal-core PVDF fiber was used as a bionic airflow sensor, and a mechanical model of this sensor was derived. The airflow sensing capability of the PVDF fiber was experimentally confirmed in a miniature wind tunnel. The results showed that a cantilevered metal-core PVDF fiber is capable of detecting the range

  5. A Dual Conductance Sensor for Simultaneous Measurement of Void Fraction and Structure Velocity of Downward Two-Phase Flow in a Slightly Inclined Pipe

    Directory of Open Access Journals (Sweden)

    Yeon-Gun Lee

    2017-05-01

    Full Text Available In this study, a new and improved electrical conductance sensor is proposed for application not only to a horizontal pipe, but also an inclined one. The conductance sensor was designed to have a dual layer, each consisting of a three-electrode set to obtain two instantaneous conductance signals in turns, so that the area-averaged void fraction and structure velocity could be measured simultaneously. The optimum configuration of the electrodes was determined through numerical analysis, and the calibration curves for stratified and annular flow were obtained through a series of static experiments. The fabricated conductance sensor was applied to a 45 mm inner diameter U-shaped downward inclined pipe with an inclination angle of 3° under adiabatic air-water flow conditions. In the tests, the superficial velocities ranged from 0.1 to 3.0 m/s for water and from 0.1 to 18 m/s for air. The obtained mean void fraction and the structure velocity from the conductance sensor were validated against the measurement by the wire-mesh sensor and the cross-correlation technique for the visualized images, respectively. The results of the flow regime classification and the corresponding time series of the void fraction at a variety of flow velocities were also discussed.

  6. A Dual Conductance Sensor for Simultaneous Measurement of Void Fraction and Structure Velocity of Downward Two-Phase Flow in a Slightly Inclined Pipe.

    Science.gov (United States)

    Lee, Yeon-Gun; Won, Woo-Youn; Lee, Bo-An; Kim, Sin

    2017-05-08

    In this study, a new and improved electrical conductance sensor is proposed for application not only to a horizontal pipe, but also an inclined one. The conductance sensor was designed to have a dual layer, each consisting of a three-electrode set to obtain two instantaneous conductance signals in turns, so that the area-averaged void fraction and structure velocity could be measured simultaneously. The optimum configuration of the electrodes was determined through numerical analysis, and the calibration curves for stratified and annular flow were obtained through a series of static experiments. The fabricated conductance sensor was applied to a 45 mm inner diameter U-shaped downward inclined pipe with an inclination angle of 3° under adiabatic air-water flow conditions. In the tests, the superficial velocities ranged from 0.1 to 3.0 m/s for water and from 0.1 to 18 m/s for air. The obtained mean void fraction and the structure velocity from the conductance sensor were validated against the measurement by the wire-mesh sensor and the cross-correlation technique for the visualized images, respectively. The results of the flow regime classification and the corresponding time series of the void fraction at a variety of flow velocities were also discussed.

  7. First Experience with the LHC Cryogenic Instrumentation

    CERN Document Server

    Vauthier, N; Balle, Ch; Casas-Cubillos, J; Ciechanowski, M; Fernandez-Penacoba, G; Fortescue-Beck, E; Gomes, P; Jeanmonod, N; Lopez-Lorente, A; Suraci, A

    2008-01-01

    The LHC under commissioning at CERN will be the world's largest superconducting accelerator and therefore makes extensive use of cryogenic instruments. These instruments are installed in the tunnel and therefore have to withstand the LHC environment that imposes radiation-tolerant design and construction. Most of the instruments require individual calibration; some of them exhibit several variants as concerns measuring span; all relevant data are therefore stored in an Oracle® database. Those data are used for the various quality assurance procedures defined for installation and commissioning, as well as for generating tables used by the control system to configure automatically the input/output channels. This paper describes the commissioning of the sensors and the corresponding electronics, the first measurement results during the cool-down of one machine sector; it discusses the different encountered problems and their corresponding solutions.

  8. Advanced ACTPol Cryogenic Detector Arrays and Readout

    CERN Document Server

    Henderson, S W; Austermann, J; Baildon, T; Battaglia, N; Beall, J A; Becker, D; De Bernardis, F; Bond, J R; Calabrese, E; Choi, S K; Coughlin, K P; Crowley, K T; Datta, R; Devlin, M J; Duff, S M; Dunner, R; Dunkley, J; van Engelen, A; Gallardo, P A; Grace, E; Hasselfield, M; Hills, F; Hilton, G C; Hincks, A D; Hlozek, R; Ho, S P; Hubmayr, J; Huffenberger, K; Hughes, J P; Irwin, K D; Koopman, B J; Kosowsky, A B; Li, D; McMahon, J; Munson, C; Nati, F; Newburgh, L; Niemack, M D; Niraula, P; Page, L A; Pappas, C G; Salatino, M; Schillaci, A; Schmitt, B L; Sehgal, N; Sherwin, B D; Sievers, J L; Simon, S M; Spergel, D N; Staggs, S T; Stevens, J R; Thornton, R; Van Lanen, J; Vavagiakis, E M; Ward, J T; Wollack, E J

    2015-01-01

    Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope (ACT), adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28-230 GHz). Its maps of primary and secondary cosmic microwave background (CMB) anisotropies -- imaged in intensity and polarization at few arcminute-scale resolution -- will enable precision cosmological constraints and also a wide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the Advanced ACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor (TES) polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new ...

  9. Water temperature effect on upward air-water flow in a vertical pipe: Local measurements database using four-sensor conductivity probes and LDA

    Science.gov (United States)

    Monrós-Andreu, G.; Chiva, S.; Martínez-Cuenca, R.; Torró, S.; Juliá, J. E.; Hernández, L.; Mondragón, R.

    2013-04-01

    Experimental work was carried out to study the effects of temperature variation in bubbly, bubbly to slug transition. Experiments were carried out in an upward air-water flow configuration. Four sensor conductivity probes and LDA techniques was used together for the measurement of bubble parameters. The aim of this paper is to provide a bubble parameter experimental database using four-sensor conductivity probes and LDA technique for upward air-water flow at different temperatures and also show transition effect in different temperatures under the boiling point.

  10. Water temperature effect on upward air-water flow in a vertical pipe: Local measurements database using four-sensor conductivity probes and LDA

    Directory of Open Access Journals (Sweden)

    Hernández L.

    2013-04-01

    Full Text Available Experimental work was carried out to study the effects of temperature variation in bubbly, bubbly to slug transition. Experiments were carried out in an upward air-water flow configuration. Four sensor conductivity probes and LDA techniques was used together for the measurement of bubble parameters. The aim of this paper is to provide a bubble parameter experimental database using four-sensor conductivity probes and LDA technique for upward air-water flow at different temperatures and also show transition effect in different temperatures under the boiling point.

  11. Experimental Characterization of a Thermopile with Aluminum-n-type Polysilicon Junctions as a Base for Multi-directional Flow Sensor Implemented in a Silicon Chip

    Directory of Open Access Journals (Sweden)

    Muh. Thamrin

    2007-11-01

    Full Text Available A multi-directional flow sensor has been realized. The essential part of the considered sensor is a thermopile configuration, which enables the measurement of the flow speed and the flow direction. The thermopile is a series arrangement of eight thermocouples. A thermocouple converts a difference in temperature into an electrical signal, by means of the Seebeck effect. The thermocouples are made of aluminum-N-type polysilicon junctions. The incoming flow is heated and the degree of heat transfer by convection to the flow, depends on the speed of the flow; the faster the flow the smaller the heat transfer, which leads to a smaller (Seebeck output voltage of the thermopiles. After signal conditioning - i.e., filtering and amplification by means of an amplification system - the electrical output signals of the thermopiles are further signal-processed by applying analog-to-digital signal conversion, so that finally the flow speed and flow direction can be properly displayed on a computer screen. The measured values of the thermopower were in the range of: 0.433 mV/K to 0.6754 mV/K, which are in good agreement with the values found in the literature: 0.5 to 0.7 mV/K. In addition it was found that the flow speed U is proportional to the reciprocal value of the square root of the output voltage of the outgoing thermopile.

  12. Studies of complex terrain wind flows using acoustic sounder and optical cross-wind remote sensors

    Energy Technology Data Exchange (ETDEWEB)

    Porch, W.M.; Neff, W.; King, C.

    1985-08-01

    Remote sensing instrumentation has played an important role in the Atmospheric Studies in Complex Terrain (ASCOT) field experimental program. The goal of this program is to better understand transport and diffusion processes in complex terrain with an emphasis focused on nighttime drainage wind conditions. Two aspects of the instrumentation are discussed in this paper: acoustic sounders (doppler and monostatic) and space averaging optical cross-wind sensors. Data from these two sources are discussed and compared with data from conventional tower and tethersonde instrumentation. 13 refs., 10 figs. (WRF)

  13. A Shape Memory Alloy Based Cryogenic Thermal Conduction Switch

    Science.gov (United States)

    Notardonato, W. U.; Krishnan, V. B.; Singh, J. D.; Woodruff, T. R.; Vaidyanathan, R.

    2005-01-01

    Shape memory alloys (SMAs) can produce large strains when deformed (e.g., up to 8%). Heating results in a phase transformation and associated recovery of all the accumulated strain. This strain recovery can occur against large forces, resulting in their use as actuators. Thus an SMA element can integrate both sensory and actuation functions, by inherently sensing a change in temperature and actuating by undergoing a shape change as a result of a temperature-induced phase transformation. Two aspects of our work on cryogenic SMAs are addressed here. First - a shape memory alloy based cryogenic thermal conduction switch for operation between dewars of liquid methane and liquid oxygen in a common bulkhead arrangement is discussed. Such a switch integrates the sensor element and the actuator element and can be used to create a variable thermal sink to other cryogenic tanks for liquefaction, densification, and zero boil-off systems for advanced spaceport applications. Second - fabrication via arc-melting and subsequent materials testing of SMAs with cryogenic transformation temperatures for use in the aforementioned switch is discussed.

  14. Transient analysis of chilldown in a cryogenic transfer line

    Science.gov (United States)

    Martin, T.

    1990-01-01

    A numerical model was developed, with the SINDA'85/FLUINT program, for calculating the thermal and hydrodynamic transients that occur during the chilldown of a cryogenic transfer line, using a well documented test case to validate the modeling process. Using this model, a total of ten cases were analyzed to evaluate the effects of variable inlet valve position, inlet pressures, and the use of an internal flow liner to promote nucleate boiling. It was found that an efficient transfer line cooldown can be achieved if the inlet flow is throttled, to reduce the flow rate and quality, and an internal flow liner such as Teflon is used.

  15. Contactless Measurement of Magnetic Nanoparticles on Lateral Flow Strips Using Tunneling Magnetoresistance (TMR Sensors in Differential Configuration

    Directory of Open Access Journals (Sweden)

    Huaming Lei

    2016-12-01

    Full Text Available Magnetic nanoparticles (MNPs are commonly used in biomedical detection due to their capability to bind with some specific antibodies. Quantification of biological entities could be realized by measuring the magnetic response of MNPs after the binding process. This paper presents a contactless scanning prototype based on tunneling magnetoresistance (TMR sensors for quantification of MNPs present in lateral flow strips (LFSs. The sensing unit of the prototype composes of two active TMR elements, which are parallel and closely arranged to form a differential sensing configuration in a perpendicular magnetic field. Geometrical parameters of the configuration are optimized according to theoretical analysis of the stray magnetic field produced by the test line (T-line while strips being scanned. A brief description of our prototype and the sample preparation is presented. Experimental results show that the prototype exhibits the performance of high sensitivity and strong anti-interference ability. Meanwhile, the detection speed has been improved compared with existing similar techniques. The proposed prototype demonstrates a good sensitivity for detecting samples containing human chorionic gonadotropin (hCG at a concentration of 25 mIU/mL. The T-line produced by the sample with low concentration is almost beyond the visual limit and produces a maximum stray magnetic field some 0.247 mOe at the sensor in the x direction.

  16. The primary cilium as sensor of fluid flow: new building blocks to the model

    DEFF Research Database (Denmark)

    Prætorius, Helle

    2015-01-01

    functionally as an organelle that makes cells more susceptible to changes in fluid flow. Thus the primary cilium was suggested to function as a flow-sensing device. This characterization has been substantiated for many epithelial cell types over the years. Nevertheless, part of the central mechanism of signal......The primary cilium is an extraordinary organelle. For many years, it had the full attention of only a few dedicated scientists fascinated by its uniqueness. Unexpectedly, after decades of obscurity, it has moved very quickly into the limelight with the increasing evidence of its central role...... transduction has not been explained, largely because of the substantial technical challenges of working with this delicate organelle. The current review considers the recent advances that allow us to fill some of the holes in the model of signal transduction in cilium-mediated responses to fluid flow...

  17. Manipulation of Protein Translocation through Nanopores by Flow Field Control and Application to Nanopore Sensors.

    Science.gov (United States)

    Hsu, Wei-Lun; Daiguji, Hirofumi

    2016-09-20

    The control of biomolecule translocation through nanopores is important in nanopore protein detection. Improvement in current nanopore molecule control is desired to enhance capture rates, extend translocation times, and ensure the effective detection of various proteins in the same solutions. We present a method that simultaneously resolves these issues through the use of a gate-modulated conical nanopore coupled with solutions of varying salt concentration. Simulation results show that the presence of an induced reverse electroosmotic flow (IREOF) results in inlet flows from the two ends of the nanopore centerline entering into the nanopore in opposite directions, which simultaneously elevates the capture rate and immobilizes the protein in the nanopore, thus enabling steady current blockage measurements for a range of proteins. In addition, it is shown that proteins with different size/charge ratios can be trapped by a gate modulation intensified flow field at a similar location in the nanopore in the same solution conditions.

  18. Cryogenic holographic distortion testing

    Science.gov (United States)

    Michel, David G.

    1994-06-01

    Hughes cryogenic holographic test facility allows for the rapid characterization of optical components and mechanical structures at elevated and reduced temperatures. The facility consists of a 1.6 meter diameter thermal vacuum chamber, vibration isolated experiment test platform, and a holographic camera assembly. Temperatures as low as 12 Kelvin and as high as 350 Kelvin have been demonstrated. Complex aspheric mirrors are tested without the need for auxiliary null lenses and may be tested in either the polished or unpolished state. Structural elements such as optical benches, solar array panels, and spacecraft antennas have been tested. Types of materials tested include beryllium, silicon carbide, aluminum, graphite epoxy, silicon/aluminum matrix material and injection molded plastics. Sizes have ranged from 7 cm X 15 cm to 825 cm X 1125 cm and have weighed as little as 0.2 Kg and as much as 130 Kg. Surface figure changes as little as (lambda) /10 peak-to-valley ((lambda) equals .514 micrometers ) are routinely measured.

  19. Numerical Study on Cryogenic Coflowing Jets under Transcritical Conditions

    Science.gov (United States)

    Tani, Hiroumi; Teramoto, Susumu; Okamoto, Koji; Yamanishi, Nobuhiro

    2012-11-01

    A numerical and experimental study is presented on cryogenic coflowing jets under transcritical conditions for a better understanding of the propellant mixing in supercritical-pressure rocket engines. The major concerns are dominant flow structures in the mixing of cryogenic coflowing jets under transcritical conditions. Experimentally, in advance of detailed numerical simulations, cryogenic nitrogen/gaseous nitrogen coaxial jets were visualized by the backlighting photography technique. It was observed that a dense nitrogen core has a shear-layer instability near the injector exit and eventually breaks up into large lumps which dissolve and fade away downstream. In numerical simulations, LES technique was employed for more detailed discussion on the flow structures. LES of a cryogenic nitrogen/gaseous nitrogen coflowing plane jet was conducted with the same density and velocity ratios of inner/outer jets as the experiments. As observed in the experiments, the shear-layer instability in the inner mixing layers is predominant near the injector exit. After roll-up and paring, the shear-layer instability waves become large-scale vortices. They cause coherent vortex structures which become dominant in the downstream and break the dense core into lumps. Strouhal numbers of the shear-layer instability and the dense lump shedding in the numerical simulations were comparable to those measured in the experiments, respectively.

  20. The Development of the Control System for the Cryogenics in the LHC Tunnel

    CERN Document Server

    Fluder, C; Casas-Cubillos, J; Dubert, P; Gomes, P; Pezzetti, M; Tovar-Gonzalez, A; Zwalinski, L

    2011-01-01

    The Large Hadron Collider (LHC) was commissioned at CERN and started operation with beams in 2008. The LHC makes extensive use of superconductors, in magnets, electrical feed boxes and accelerating cavities, which are operated at cryogenic temperatures. The process automation for the cryogenic distribution around the 27 km accelerator circumference is based on 18 Programmable Logic Controllers (PLCs); overall, they handle 4 000 control loops and 8 000 alarms and interlocks; 16 000 cryogenic sensors and actuators are accessed through industrial field networks. This paper reviews the control system architecture and the main hardware and software components; presents the hardware commissioning and software production methodologies; and illustrates some of the problems faced during development, commissioning and nominal cryogenics operation, together with the solutions applied.

  1. Clementine sensor suite

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    LLNL designed and built the suite of six miniaturized light-weight space-qualified sensors utilized in the Clementine mission. A major goal of the Clementine program was to demonstrate technologies originally developed for Ballistic Missile Defense Organization Programs. These sensors were modified to gather data from the moon. This overview presents each of these sensors and some preliminary on-orbit performance estimates. The basic subsystems of these sensors include optical baffles to reject off-axis stray light, light-weight ruggedized optical systems, filter wheel assemblies, radiation tolerant focal plane arrays, radiation hardened control and readout electronics and low mass and power mechanical cryogenic coolers for the infrared sensors. Descriptions of each sensor type are given along with design specifications, photographs and on-orbit data collected.

  2. Dependence of composition of stable molecules in N2-H2 plasmas on nitrogen gas flow rate ratio measured using a quartz sensor

    Science.gov (United States)

    Suzuki, Atsushi; Asahina, Shuichi

    2014-11-01

    Compositions of stable molecules in N2-H2 plasmas measured using a quartz sensor (Q-sensor) were compared with those measured using a quadrupole mass spectrometer (QMS) under various nitrogen gas flow rate ratio to determine the applicability of Q-sensor measurement to N2-H2 plasmas. The nitrogen flow rate ratio dependence of the Q-sensor results obtained 20 mm from the edge of the plasma electrodes (Z = 20 mm) tended to agree more qualitatively with the NH3 density measured by QMS compared with those measured at 70 mm. For pure nitrogen or hydrogen plasma, the results measured at Z = 20 mm differed from those of gas analyses using QMS. The analysis indicated that Q-sensor results obtained near discharges with various nitrogen flow rate ratios reflect information on stable molecules such as N2, H2, and NH3 but yield information on other stable molecules or other chemical species in pure N2 and H2 plasmas.

  3. Construction and Use of Flow Cytometry Optimized Plasmid-Sensor Strains

    DEFF Research Database (Denmark)

    Bahl, Martin Iain; Oregaard, Gunnar; Sørensen, Søren Johannes;

    2009-01-01

    stability of the plasmid is high. The method presented here relies on a phenotypic (green fluorescence protein) marker, which is switched on if the host bacteria loses the residing plasmid. The incorporation of flow cytometry for single-cell detection and discrimination between plasmid-free and plasmid...

  4. A new fibre-optic sensor for high-temperature flow measurement

    NARCIS (Netherlands)

    Schiferli, W.; Cheng, L.K.; Jansen, T.H.

    2012-01-01

    Measuring flow is essentia ìn the process and oil & gas ìndustry. In the oil and gas industry, orifice plates and vortex meters are popular, since their lack of moving parts makes them robust. However, the need for electronics limits maximum process temperatures to 150 to 200'C. Special electronics

  5. Cryogenic Pressure Calibration Facility Using a Cold Force Reference

    CERN Document Server

    Bager, T; Métral, L

    1999-01-01

    Presently various commercial cryogenic pressure sensors are being investigated for installation in the LHC collider, they will eventually be used to assess that the magnets are fully immersed in liquid and to monitor fast pressure transients. In the framework of this selection procedure a cryogenic pressue calibration facility has been designed and built; it is based on a cryogenic primary pressure reference made of a bellows that converts the pressure into a force measurement. For that a shaft transfers this force to a precision force transducer at room temperature. Knowing the liquid bath pessure and the surface area of the bellows the pressure applied to the transducers under calibration is calculated; corrections due to thermal contraction are introduced. To avoid loss of force in the bellows wall its length is maintained constant; a cold capacitive displacement sensor measures this. The calibration temperature covers 1.5 K to 4.2 K and the pressure 0 to 20 bar. In contrast with more classical techniques ...

  6. Cryogenics bringing the temperature down, underground

    CERN Multimedia

    2005-01-01

    The first 600m of the LHC cryogenic distribution line (QRL), which will feed the accelerator's superconducting magnets, has passed initial validating tests of its mechanical design at room and cryogenic temperatures.

  7. Cryogenic engineering fifty years of progress

    CERN Document Server

    Reed, Richard

    2007-01-01

    Cryogenic Engineering: Fifty Years of Progress is a benchmark reference work which chronicles the major developments in the field. Starting with an historical background dating to the 1850s, this book reviews the development of data resources now available for cryogenic fields and properties of materials. The advances in cryogenic fundamentals are covered by reviews of cryogenic principles, cryogenic insulation, low-loss storage systems, modern liquefaction processes, helium cryogenics and low-temperature thermometry. Several well-established applications resulting from cryogenic advances include aerospace cryocoolers and refrigerators, use of LTS and HTS systems in electrical applications, and recent changes in cryopreservation. Extensive references are provided for the readers interested in the details of these cryogenic engineering advances.

  8. BOSCH热膜式空气质量流量传感器的分析%The Analysis of BOSCH Hot-film Air Flow Sensor

    Institute of Scientific and Technical Information of China (English)

    刘艳伟; 文昊; 李文中

    2012-01-01

    本文主要对BOSCH公司的热膜式空气质量流量传感器做了详细的分析研究。首先对空气流量质量传感器在汽车上的重要性进行了简单地叙述,接着重点分析了BOSCH公司的热膜式空气质量流量传感器,最后对汽车空气质量流量传感器的前景进行了展望。%In this paper, the hot-film air mass flow sensor in the BOSCH company made a detailed analyzed. First a simple account of the importance of the quality of the air flow sensor in the car, Then analyzes the BOSCH company's hot-film air mass flow sensor, Finally, the prospects of the automotive air mass flow sensor

  9. Design and integration of a generic disposable array-compatible sensor housing into an integrated disposable indirect microfluidic flow injection analysis system.

    Science.gov (United States)

    Rapp, Bastian E; Schickling, Benjamin; Prokop, Jürgen; Piotter, Volker; Rapp, Michael; Länge, Kerstin

    2011-10-01

    We describe an integration strategy for arbitrary sensors intended to be used as biosensors in biomedical or bioanalytical applications. For such devices ease of handling (by a potential end user) as well as strict disposable usage are of importance. Firstly we describe a generic array compatible polymer sensor housing with an effective sample volume of 1.55 μl. This housing leaves the sensitive surface of the sensor accessible for the application of biosensing layers even after the embedding. In a second step we show how this sensor housing can be used in combination with a passive disposable microfluidic chip to set up arbitrary 8-fold sensor arrays and how such a system can be complemented with an indirect microfluidic flow injection analysis (FIA) system. This system is designed in a way that it strictly separates between disposable and reusable components- by introducing tetradecane as an intermediate liquid. This results in a sensor system compatible with the demands of most biomedical applications. Comparative measurements between a classical macroscopic FIA system and this integrated indirect microfluidic system are presented. We use a surface acoustic wave (SAW) sensor as an exemplary detector in this work.

  10. The primary cilium as sensor of fluid flow: new building blocks to the model

    DEFF Research Database (Denmark)

    Prætorius, Helle

    2015-01-01

    The primary cilium is an extraordinary organelle. For many years, it had the full attention of only a few dedicated scientists fascinated by its uniqueness. Unexpectedly, after decades of obscurity, it has moved very quickly into the limelight with the increasing evidence of its central role...... in the many genetic variations that lead to what are now known as ciliopathies. These studies implicated unique biological functions of the primary cilium, which are not completely straightforward. In parallel, and initially completely unrelated to the ciliopathies, the primary cilium was characterized...... functionally as an organelle that makes cells more susceptible to changes in fluid flow. Thus the primary cilium was suggested to function as a flow-sensing device. This characterization has been substantiated for many epithelial cell types over the years. Nevertheless, part of the central mechanism of signal...

  11. Simultaneous measurements of multiple flow parameters for scramjet characterization using tunable diode-laser sensors

    OpenAIRE

    Li, Fei; Yu, XiLong; Gu, Hongbin; Li, Zhi; Zhao, Yan; Ma, Lin; Chen, Lihong; Chang, Xinyu

    2011-01-01

    This paper reports the simultaneous measurements of multiple flow parameters in a scramjet facility operating at a nominal Mach number of 2.5 using a sensing system based on tunable diode-laser absorption spectroscopy (TDLAS). The TDLAS system measures velocity, temperature, and water vapor partial pressure at three different locations of the scramjet: the inlet, the combustion region near the flame stabilization cavity, and the exit of the combustor. These measurements enable the determinati...

  12. Sapflow+: a four-needle heat-pulse sap flow sensor enabling nonempirical sap flux density and water content measurements.

    Science.gov (United States)

    Vandegehuchte, Maurits W; Steppe, Kathy

    2012-10-01

    • To our knowledge, to date, no nonempirical method exists to measure reverse, low or high sap flux density. Moreover, existing sap flow methods require destructive wood core measurements to determine sapwood water content, necessary to convert heat velocity to sap flux density, not only damaging the tree, but also neglecting seasonal variability in sapwood water content. • Here, we present a nonempirical heat-pulse-based method and coupled sensor which measure temperature changes around a linear heater in both axial and tangential directions after application of a heat pulse. By fitting the correct heat conduction-convection equation to the measured temperature profiles, the heat velocity and water content of the sapwood can be determined. • An identifiability analysis and validation tests on artificial and real stem segments of European beech (Fagus sylvatica L.) confirm the applicability of the method, leading to accurate determinations of heat velocity, water content and hence sap flux density. • The proposed method enables sap flux density measurements to be made across the entire natural occurring sap flux density range of woody plants. Moreover, the water content during low flows can be determined accurately, enabling a correct conversion from heat velocity to sap flux density without destructive core measurements. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  13. Solution Concentration and Flow Rate of Fe3+-modified Porphyrin (Red Blood Model) on Giant Magnetoresistance (GMR) Sensor Efficiency

    Science.gov (United States)

    Aminudin, A.; Tjahyono, D. H.; Suprijadi; Djamal, M.; Zaen, R.; Nandiyanto, A. B. D.

    2017-03-01

    Red blood has been of great interest for scientists since it relates to human’ and living creature’s life sustainability. One of the important compounds in red blood is porphyrin. Here, the purpose of this study was to develop a method for detecting porphyrin concentration using the assistance of giant magnetoresistance. In short of the method, we added Fe3+ solution to the porphyrin, and the mixed solution was introduced to the magnetic field. Next, the magnetized solution was introduced to the magnetic sensor to indicate the existence of porphyrin in the solution. To confirm the effectiveness of our method in detecting porphyrin, we varied the flow rate and concentration of Fe3+-modified porphyrin solution. The result showed that the more concentration and the slower flow rate affected the higher sensitivity gained. Since this developed method is simple but effective for detecting porphyrin concentration, we believe that further development of this method will be benefit for many applications, specifically relating to the medical uses.

  14. An accurate, flexible and small optical fiber sensor: a novel technological breakthrough for real-time analysis of dynamic blood flow data in vivo.

    Science.gov (United States)

    Yuan, Qiao-ying; Zhang, Ling; Xiao, Dan; Zhao, Kun; Lin, Chun; Si, Liang-yi

    2014-01-01

    Because of the limitations of existing methods and techniques for directly obtaining real-time blood data, no accurate microflow in vivo real-time analysis method exists. To establish a novel technical platform for real-time in vivo detection and to analyze average blood pressure and other blood flow parameters, a small, accurate, flexible, and nontoxic Fabry-Perot fiber sensor was designed. The carotid sheath was implanted through intubation of the rabbit carotid artery (n = 8), and the blood pressure and other detection data were determined directly through the veins. The fiber detection results were compared with test results obtained using color Doppler ultrasound and a physiological pressure sensor recorder. Pairwise comparisons among the blood pressure results obtained using the three methods indicated that real-time blood pressure information obtained through the fiber sensor technique exhibited better correlation than the data obtained with the other techniques. The highest correlation (correlation coefficient of 0.86) was obtained between the fiber sensor and pressure sensor. The blood pressure values were positively related to the total cholesterol level, low-density lipoprotein level, number of red blood cells, and hemoglobin level, with correlation coefficients of 0.033, 0.129, 0.358, and 0.373, respectively. The blood pressure values had no obvious relationship with the number of white blood cells and high-density lipoprotein and had a negative relationship with triglyceride levels, with a correlation coefficient of -0.031. The average ambulatory blood pressure measured by the fiber sensor exhibited a negative correlation with the quantity of blood platelets (correlation coefficient of -0.839, Preal time; the sensor can also determine the content and status of the blood flow to some extent. Therefore, the fiber sensor can obtain partially real-time vascular rheology information and may thus enable the early diagnosis of blood rheology disorders and

  15. Microfluidic Flow-Through Reactor with Electrochemical Sensor Array for Real-Time Pcr

    Science.gov (United States)

    Teh, Huey-Fang; Ramalingam, Naveen; Gong, Hai-Qing; Tan, Swee-Ngin

    We developed an integrated microfluidic flow-through EC-PCR (EC-PCR) microdevice for the concurrent DNA amplification, PCR products EC detection and PCR products quantification instead of the current available fluorescence detection scheme. The microfluidic flow-through EC-PCR microdevice was fabricated with the state-of-the-art microfabrication technology, by bonding a bottom glass substrate having a microelectrode array to a top glass cover having the microchannels made of PDMS material. Both the amplification of the target DNA sequence and the subsequent EC detection of the PCR products were carried out concurrently on the integrated device by real-time monitoring. The underlying principle of the microfluidic flow-through EC-PCR method was based on the changes of current signal of methylene blue (MB), which worked as an electrochemically active species DNA intercalator in the PCR mixture, during the amplification process at the extension phase. The results shown in this work indicated that the nucleic acid analysis could be performed in a fast thermal cycling and true real-time quantitative electrochemical detection. The signal variation trends of the EC detection and the fluorescence detection were the same in our verification measurements for both methods, which suggested that the EC detection method was feasible for this application.

  16. 浮子流量传感器粘度影响的研究%Study of Viscosity Effect on Float Flow Sensor

    Institute of Scientific and Technical Information of China (English)

    雷静; 张涛; 蒋伟

    2014-01-01

    The viscosity impact on float flow sensor was investigated.Experimental results show that the im-pact error from 4050 aviation lubricant with the viscosity ranging from 10 ~50mm2/s on the float flow sensor can be about 10%;and based on the boundary layer theory and considering conditions of fluid flow inside as well as the simulation with CFD software,the error of the viscosity’s influence on the DN40mm float flow sen-sor can be controlled within 5%.From the angle of the flow field analysis,analyzing float flow sensor’s vis-cosity influence law and mechanism and modeling the simulation model can provide the reference for the simu-lation of flow sensor later.%通过研究粘度对浮子流量传感器测量的影响,运用实验手段,测出粘度为10~50mm2/s 的4050航空润滑油对浮子流量传感器的影响误差约为10%左右。结合浮子流量传感器的边界层理论与内部流体流动情况,运用 CFD软件仿真,将粘度对 DN40mm 浮子流量传感器影响误差控制在5%以内。从流场的角度分析浮子流量传感器粘度影响规律及其机理,并且模式化仿真模型,为以后流量传感器的仿真提供了借鉴作用。

  17. Thermodynamic properties of cryogenic fluids

    CERN Document Server

    Leachman, Jacob; Lemmon, Eric; Penoncello, Steven

    2017-01-01

    This update to a classic reference text provides practising engineers and scientists with accurate thermophysical property data for cryogenic fluids. The equations for fifteen important cryogenic fluids are presented in a basic format, accompanied by pressure-enthalpy and temperature-entropy charts and tables of thermodynamic properties. It begins with a chapter introducing the thermodynamic relations and functional forms for equations of state, and goes on to describe the requirements for thermodynamic property formulations, needed for the complete definition of the thermodynamic properties of a fluid. The core of the book comprises extensive data tables and charts for the most commonly-encountered cryogenic fluids. This new edition sees significant updates to the data presented for air, argon, carbon monoxide, deuterium, ethane, helium, hydrogen, krypton, nitrogen and xenon. The book supports and complements NIST’s REFPROP - an interactive database and tool for the calculation of thermodynamic propertie...

  18. Cryogenic safety organisation at CERN

    CERN Document Server

    CERN. Geneva

    2016-01-01

    With Safety being a top priority of CERN’s general policy, the Organisation defines and implements a Policy that sets out the general principles governing Safety at CERN. To the end of the attainment of said Safety objectives, the organic units (owners/users of the equipment) are assigned the responsibility for the implementation of the CERN Safety Policy at all levels of the organization, whereas the Health and Safety and Environmental Protection Unit (HSE) has the role of providing assistance for the implementation of the Safety Policy, and a monitoring role related to the implementation of continuous improvement of Safety, compliance with the Safety Rules and the handling of emergency situations. This talk will elaborate on the roles, responsibilities and organisational structure of the different stakeholders within the Organization with regards to Safety, and in particular to cryogenic safety. The roles of actors of particular importance such as the Cryogenic Safety Officers (CSOs) and the Cryogenic Sa...

  19. Integrated Cryogenic Propulsion Test Article Thermal Vacuum Hotfire Testing

    Science.gov (United States)

    Morehead, Robert L.; Melcher, J. C.; Atwell, Matthew J.; Hurlbert, Eric A.

    2017-01-01

    In support of a facility characterization test, the Integrated Cryogenic Propulsion Test Article (ICPTA) was hotfire tested at a variety of simulated altitude and thermal conditions in the NASA Glenn Research Center Plum Brook Station In-Space Propulsion Thermal Vacuum Chamber (formerly B2). The ICPTA utilizes liquid oxygen and liquid methane propellants for its main engine and four reaction control engines, and uses a cold helium system for tank pressurization. The hotfire test series included high altitude, high vacuum, ambient temperature, and deep cryogenic environments, and several hundred sensors on the vehicle collected a range of system level data useful to characterize the operation of an integrated LOX/Methane spacecraft in the space environment - a unique data set for this propellant combination.

  20. Distributed Cooling in Cryogenics with Miniaturized Fluid Circuits

    CERN Document Server

    Grohmann, Steffen

    This work presents the development of miniaturized cryogenic fluid circuits for cooling of low temperature tracking detectors in High Energy Physics (HEPI. The system development comprises the circuit layout and control, and the design of major circuit components. It includes the development of a prototype cryogenic micropump compatible with cooling powers of about l0 W to l00 W, and capable of producing pressure heads of several bars. Focus is given to the design of microtube heat exchangers for direct evaporative cooling of sensors and electronic devices. Extensive experimental investigations on heat transfer in microtubes of 250 $\\mu m$ and 500 $\\mu m$ diameter are presented, carried out with argon at about 120 K. A new relative roughness parameter is introduced to model the effect of macroscopic surface roughness on convective heat transfer. An extension of the diameter function in the VDI Heat Atlas correlation for nucleate boiling in vertical tubes is proposed. Besides HEP, potential applications are es...