Measurement of Gas-Liquid Two-Phase Flow in Micro-Pipes by a Capacitance Sensor

PubMed Central

Ji, Haifeng; Li, Huajun; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

2014-01-01

A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used to measure the small capacitance signals based on the differential sampling method. The performance and feasibility of the capacitance method are investigated and discussed. The capacitance signal is analyzed, which can reflect the voidage variation of two-phase flow. The gas slug velocity is determined through a cross-correlation technique using two identical capacitance sensors. The simulation and experimental results show that the presented capacitance measurement system is successful. Research work also verifies that the capacitance sensor is an effective method for the measurement of gas liquid two-phase flow parameters in micro-pipes. PMID:25587879

Measurement of gas-liquid two-phase flow in micro-pipes by a capacitance sensor.

PubMed

Ji, Haifeng; Li, Huajun; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

2014-11-26

A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used to measure the small capacitance signals based on the differential sampling method. The performance and feasibility of the capacitance method are investigated and discussed. The capacitance signal is analyzed, which can reflect the voidage variation of two-phase flow. The gas slug velocity is determined through a cross-correlation technique using two identical capacitance sensors. The simulation and experimental results show that the presented capacitance measurement system is successful. Research work also verifies that the capacitance sensor is an effective method for the measurement of gas liquid two-phase flow parameters in micro-pipes.

Flow direction measurement criteria and techniques planned for the 40- by 80-/80- x 120-foot wind tunnel integrated systems tests

NASA Technical Reports Server (NTRS)

Zell, P. T.; Hoffmann, J.; Sandlin, D. R.

1985-01-01

A study was performed in order to develop the criteria for the selection of flow direction indicators for use in the Integrated Systems Tests (ISTs) of the 40 by 80/80 by 120 Foot Wind Tunnel System. The problems, requirements, and limitations of flow direction measurement in the wind tunnel were investigated. The locations and types of flow direction measurements planned in the facility were discussed. A review of current methods of flow direction measurement was made and the most suitable technique for each location was chosen. A flow direction vane for each location was chosen. A flow direction vane that employs a Hall Effect Transducer was then developed and evaluated for application during the ISTs.

Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1997-06-24

A system is described for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit. 2 figs.

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

PubMed Central

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

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 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. PMID:26501288

An Integrated Instrumentation System for Velocity, Concentration and Mass Flow Rate Measurement of Solid Particles Based on Electrostatic and Capacitance Sensors.

PubMed

Li, Jian; Kong, Ming; Xu, Chuanlong; Wang, Shimin; Fan, Ying

2015-12-10

The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass flow rate measurement of dense phase pneumatically conveyed solid particles based on electrostatic and capacitance sensorsis developed. The electrostatic sensors are used for particle mean velocity measurement in combination with the cross-correlation technique, while the capacitance sensor with helical surface-plate electrodes, which has relatively homogeneous sensitivity distribution, is employed for the measurement of particle concentration and its capacitance is measured by an electrostatic-immune AC-based circuit. The solid mass flow rate can be further calculated from the measured velocity and concentration. The developed instrumentation system for velocity and concentration measurement is verified and calibrated on a pulley rig and through static experiments, respectively. Finally the system is evaluated with glass beads on a gravity-fed rig. The experimental results demonstrate that the system is capable of the accurate solid mass flow rate measurement, and the relative error is within -3%-8% for glass bead mass flow rates ranging from 0.13 kg/s to 0.9 kg/s.

Design and evaluation of a miniature laser speckle imaging device to assess gingival health

PubMed Central

Regan, Caitlin; White, Sean M.; Yang, Bruce Y.; Takesh, Thair; Ho, Jessica; Wink, Cherie; Wilder-Smith, Petra; Choi, Bernard

2016-01-01

Abstract. Current methods used to assess gingivitis are qualitative and subjective. We hypothesized that gingival perfusion measurements could provide a quantitative metric of disease severity. We constructed a compact laser speckle imaging (LSI) system that could be mounted in custom-made oral molds. Rigid fixation of the LSI system in the oral cavity enabled measurement of blood flow in the gingiva. In vitro validation performed in controlled flow phantoms demonstrated that the compact LSI system had comparable accuracy and linearity compared to a conventional bench-top LSI setup. In vivo validation demonstrated that the compact LSI system was capable of measuring expected blood flow dynamics during a standard postocclusive reactive hyperemia and that the compact LSI system could be used to measure gingival blood flow repeatedly without significant variation in measured blood flow values (p<0.05). Finally, compact LSI system measurements were collected from the interdental papilla of nine subjects and compared to a clinical assessment of gingival bleeding on probing. A statistically significant correlation (ρ=0.53; p<0.005) was found between these variables, indicating that quantitative gingival perfusion measurements performed using our system may aid in the diagnosis and prognosis of periodontal disease. PMID:27787545

Design and evaluation of a miniature laser speckle imaging device to assess gingival health

NASA Astrophysics Data System (ADS)

Regan, Caitlin; White, Sean M.; Yang, Bruce Y.; Takesh, Thair; Ho, Jessica; Wink, Cherie; Wilder-Smith, Petra; Choi, Bernard

2016-10-01

Current methods used to assess gingivitis are qualitative and subjective. We hypothesized that gingival perfusion measurements could provide a quantitative metric of disease severity. We constructed a compact laser speckle imaging (LSI) system that could be mounted in custom-made oral molds. Rigid fixation of the LSI system in the oral cavity enabled measurement of blood flow in the gingiva. In vitro validation performed in controlled flow phantoms demonstrated that the compact LSI system had comparable accuracy and linearity compared to a conventional bench-top LSI setup. In vivo validation demonstrated that the compact LSI system was capable of measuring expected blood flow dynamics during a standard postocclusive reactive hyperemia and that the compact LSI system could be used to measure gingival blood flow repeatedly without significant variation in measured blood flow values (p<0.05). Finally, compact LSI system measurements were collected from the interdental papilla of nine subjects and compared to a clinical assessment of gingival bleeding on probing. A statistically significant correlation (ρ=0.53 p<0.005) was found between these variables, indicating that quantitative gingival perfusion measurements performed using our system may aid in the diagnosis and prognosis of periodontal disease.

A measurement device for electromagnetic flow tomography

NASA Astrophysics Data System (ADS)

Vauhkonen, M.; Hänninen, A.; Lehtikangas, O.

2018-01-01

Electromagnetic flow meters have succesfully been used in many industries to measure the mean flow velocity of conductive liquids. This technology works reliably in single phase flows with axisymmetric flow profiles but can be inaccurate with asymmetric flows, which are encountered, for example, in multiphase flows, pipe elbows and T-junctions. Some computational techniques and measurement devices with multiple excitation coils and measurement electrodes have recently been proposed to be used in cases of asymmetric flows. In earlier studies, we proposed a computational approach for electromagnetic flow tomography (EMFT) for estimating velocity fields utilizing several excitation coils and a set of measurement electrodes attached to the surface of the pipe. This approach has been shown to work well with simulated data but has not been tested extensively with real measurements. In this paper, an EMFT system with four excitation coils and 16 measurement electrodes is introduced. The system is capable of using both square wave and sinusoidal coil current excitations and all the coils can be excited individually, also enabling parallel excitations with multiple frequencies. The studies undertaken in the paper demonstrate that the proposed EMFT system, together with the earlier introduced velocity field reconstruction approach, is capable of producing reliable velocify field estimates in a laboratory environment with both axisymmetric and asymmetric single phase flows.

Guide to Flow Measurement for Electric Propulsion Systems

NASA Technical Reports Server (NTRS)

Frieman, Jason D.; Walker, Mitchell L. R.; Snyder, Steve

2013-01-01

In electric propulsion (EP) systems, accurate measurement of the propellant mass flow rate of gas or liquid to the thruster and external cathode is a key input in the calculation of thruster efficiency and specific impulse. Although such measurements are often achieved with commercial mass flow controllers and meters integrated into propellant feed systems, the variability in potential propellant options and flow requirements amongst the spectrum of EP power regimes and devices complicates meter selection, integration, and operation. At the direction of the Committee on Standards for Electric Propulsion Testing, a guide was jointly developed by members of the electric propulsion community to establish a unified document that contains the working principles, methods of implementation and analysis, and calibration techniques and recommendations on the use of mass flow meters in laboratory and spacecraft electric propulsion systems. The guide is applicable to EP devices of all types and power levels ranging from microthrusters to high-power ion engines and Hall effect thrusters. The establishment of a community standard on mass flow metering will help ensure the selection of the proper meter for each application. It will also improve the quality of system performance estimates by providing comprehensive information on the physical phenomena and systematic errors that must be accounted for during the analysis of flow measurement data. This paper will outline the standard methods and recommended practices described in the guide titled "Flow Measurement for Electric Propulsion Systems."

Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

NASA Technical Reports Server (NTRS)

Jentink, Henk W.; Bogue, Rodney K.

2005-01-01

Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

The temperature measurement research for high-speed flow based on tunable diode laser absorption spectroscopy

NASA Astrophysics Data System (ADS)

Di, Yue; Jin, Yi; Jiang, Hong-liang; Zhai, Chao

2013-09-01

Due to the particularity of the high-speed flow, in order to accurately obtain its' temperature, the measurement system should has some characteristics of not interfereing with the flow, non-contact measurement and high time resolution. The traditional measurement method cannot meet the above requirements, however the measurement method based on tunable diode laser absorption spectroscopy (TDLAS) technology can meet the requirements for high-speed flow temperature measurement. When the near-infared light of a specific frequency is through the media to be measured, it will be absorbed by the water vapor molecules and then the transmission light intensity is detected by the detector. The temperature of the water vapor which is also the high-speed flow temperature, can be accurately obtained by the Beer-Lambert law. This paper focused on the research of absorption spectrum method for high speed flow temperature measurement with the scope of 250K-500K. Firstly, spectral line selection method for low temperature measurement of high-speed flow is discussed. Selected absorption lines should be isolated and have a high peak absorption within the range of 250-500K, at the same time the interference of the other lines should be avoided, so that a high measurement accuracy can be obtained. According to the near-infrared absorption spectra characteristics of water vapor, four absorption lines at the near 1395 nm and 1409 nm are selected. Secondly, a system for the temperature measurement of the water vapor in the high-speed flow is established. Room temperature are measured through two methods, direct absorption spectroscopy (DAS) and wavelength modulation spectroscopy (WMS) ,the results show that this system can realize on-line measurement of the temperature and the measurement error is about 3%. Finally, the system will be used for temperature measurement of the high-speed flow in the shock tunnel, its feasibility of measurement is analyzed.

Supersonic Flow Field Investigation Using a Fiber-optic based Doppler Global Velocimeter

NASA Technical Reports Server (NTRS)

Meyers, James F.; Lee, Joseph W.; Fletcher, Mark T.; Cavone, Angelo A.; AscencionGuerreroViramontes, J.

2006-01-01

A three-component fiber-optic based Doppler Global Velocimeter was constructed, evaluated and used to measure shock structures about a low-sonic boom model in a Mach 2 flow. The system was designed to have maximum flexibility in its ability to measure flows with restricted optical access and in various facilities. System layout is described along with techniques developed for production supersonic testing. System evaluation in the Unitary Plan Wind Tunnel showed a common acceptance angle of f4 among the three views with velocity measurement resolutions comparable with free-space systems. Flow field measurements of shock structures above a flat plate with an attached ellipsoid-cylinder store and a low-sonic boom model are presented to demonstrate the capabilities of the system during production testing.

A system for the real time, direct measurement of natural gas flow

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

Sowell, T.

1995-12-31

PMI/Badger Meter, Inc. with partial sponsorship from the Gas Research Institute, has designed and developed direct measurement total energy flow metering instrumentation. As industry demands for improved accuracy and speed of measurement have increased so has the complexity of the overall hardware and software systems. Considering traditional system approaches, few companies have the in house capability of maintaining a complete system. This paper addresses efforts to implement a direct, total gas energy flow metering system which is simple to use and cost effective.

Analysis of particle in liquid using excitation-fluorescence spectral flow cytometer

NASA Astrophysics Data System (ADS)

Takenaka, Kei; Togashi, Shigenori

2018-01-01

We have developed a new flow cytometer that can measure the excitation-fluorescence spectra of a single particle. This system consists of a solution-transmitting unit and an optical unit. The solution-transmitting unit allows a sample containing particles to flow through the center of a flow cell by hydrodynamic focusing. The optical unit irradiates particles with dispersed white light (wavelength band: 400-650 nm) along the flow direction and measures their fluorescence spectra (wavelength band: 400-700 nm) using a spectroscopic photodetector array. The fluorescence spectrum of a particle changes with the shift of the wavelength of the excitation light. Using this system, the excitation-fluorescence spectra of a fluorescent particle were measured. Additionally, a homogenized tomato suspension and a homogenized spinach suspension were measured using the system. Measurement results show that it is possible to determine the components of vegetables by comparing measured fluorescence spectra of particles in a vegetable suspension.

A compact x-ray system for two-phase flow measurement

NASA Astrophysics Data System (ADS)

Song, Kyle; Liu, Yang

2018-02-01

In this paper, a compact x-ray densitometry system consisting of a 50 kV, 1 mA x-ray tube and several linear detector arrays is developed for two-phase flow measurement. The system is capable of measuring void fraction and velocity distributions with a spatial resolution of 0.4 mm per pixel and a frequency of 1000 Hz. A novel measurement model has been established for the system which takes account of the energy spectrum of x-ray photons and the beam hardening effect. An improved measurement accuracy has been achieved with this model compared with the conventional log model that has been widely used in the literature. Using this system, void fraction and velocity distributions are measured for a bubbly and a slug flow in a 25.4 mm I.D. air-water two-phase flow test loop. The measured superficial gas velocities show an error within  ±4% when compared with the gas flowmeter for both conditions.

Evaluating a Radar-Based, Non Contact Streamflow Measurement System in the San Joaquin River at Vernalis, California

USGS Publications Warehouse

Cheng, Ralph T.; Gartner, Jeffrey W.; Mason, Jr., Robert R.; Costa, John E.; Plant, William J.; Spicer, Kurt R.; Haeni, F. Peter; Melcher, Nick B.; Keller, William C.; Hayes, Ken

2004-01-01

Accurate measurement of flow in the San Joaquin River at Vernalis, California, is vital to a wide range of Federal and State agencies, environmental interests, and water contractors. The U.S. Geological Survey uses a conventional stage-discharge rating technique to determine flows at Vernalis. Since the flood of January 1997, the channel has scoured and filled as much as 20 feet in some sections near the measurement site resulting in an unstable stage-discharge rating. In response to recent advances in measurement techniques and the need for more accurate measurement methods, the Geological Survey has undertaken a technology demonstration project to develop and deploy a radar-based streamflow measuring system on the bank of the San Joaquin River at Vernalis, California. The proposed flow-measurement system consists of a ground-penetrating radar system for mapping channel geometries, a microwave radar system for measuring surface velocities, and other necessary infrastructure. Cross-section information derived from ground penetrating radar provided depths similar to those measured by other instruments during the study. Likewise, surface-velocity patterns and magnitudes measured by the pulsed Doppler radar system are consistent with near surface current measurements derived from acoustic velocity instruments. Since the ratio of surface velocity to mean velocity falls to within a small range of theoretical value, using surface velocity as an index velocity to compute river discharge is feasable. Ultimately, the non-contact radar system may be used to make continuous, near-real-time flow measurements during high and medium flows. This report documents the data collected between April 14, 2002 and May 17, 2002 for the purposes of testing this radar based system. Further analyses of the data collected during this field effort will lead to further development and improvement of the system.

Flow Pattern Phenomena in Two-Phase Flow in Microchannels

NASA Astrophysics Data System (ADS)

Keska, Jerry K.; Simon, William E.

2004-02-01

Space transportation systems require high-performance thermal protection and fluid management techniques for systems ranging from cryogenic fluid management devices to primary structures and propulsion systems exposed to extremely high temperatures, as well as for other space systems such as cooling or environment control for advanced space suits and integrated circuits. Although considerable developmental effort is being expended to bring potentially applicable technologies to a readiness level for practical use, new and innovative methods are still needed. One such method is the concept of Advanced Micro Cooling Modules (AMCMs), which are essentially compact two-phase heat exchangers constructed of microchannels and designed to remove large amounts of heat rapidly from critical systems by incorporating phase transition. The development of AMCMs requires fundamental technological advancement in many areas, including: (1) development of measurement methods/systems for flow-pattern measurement/identification for two-phase mixtures in microchannels; (2) development of a phenomenological model for two-phase flow which includes the quantitative measure of flow patterns; and (3) database development for multiphase heat transfer/fluid dynamics flows in microchannels. This paper focuses on the results of experimental research in the phenomena of two-phase flow in microchannels. The work encompasses both an experimental and an analytical approach to incorporating flow patterns for air-water mixtures flowing in a microchannel, which are necessary tools for the optimal design of AMCMs. Specifically, the following topics are addressed: (1) design and construction of a sensitive test system for two-phase flow in microchannels, one which measures ac and dc components of in-situ physical mixture parameters including spatial concentration using concomitant methods; (2) data acquisition and analysis in the amplitude, time, and frequency domains; and (3) analysis of results including evaluation of data acquisition techniques and their validity for application in flow pattern determination.

Laser Doppler velocimetry for continuous flow solar-pumped iodine laser system

NASA Technical Reports Server (NTRS)

Tabibi, Bagher M.; Lee, Ja H.

1991-01-01

A laser Doppler velocimetry (LDV) system was employed to measure the flow velocity profile of iodide vapor inside laser tubes of 36 mm ID and 20 mm ID. The LDV, which was operated in the forward scatter mode used a low power (15 mW) He-Ne laser beam. Velocity ranges from 1 m/s was measured to within one percent accuracy. The flow velocity profile across the laser tube was measured and the intensity of turbulence was determined. The flow of iodide inside the laser tube demonstrated a mixture of both turbulence and laminar flow. The flowmeter used for the laser system previously was calibrated with the LDV and found to be in good agreement.

Measuring Thermal Conductivity of a Small Insulation Sample

NASA Technical Reports Server (NTRS)

Miller, Robert A.; Kuczmarski, Maria A.

2009-01-01

A multiple-throat venturi system has been invented for measuring laminar flow of air or other gas at low speed (1 to 30 cm/s) in a duct while preserving the laminar nature of the flow and keeping the velocity profile across the duct as nearly flat as possible. While means for measuring flows at higher speeds are well established, heretofore, there have been no reliable means for making consistent, accurate measurements in this speed range. In the original application for which this system was invented, the duct leads into the test section of a low-speed wind tunnel wherein uniform, low-speed, laminar flow is required for scientific experiments. The system could also be used to monitor a slow flow of gas in an industrial process like chemical vapor deposition. In the original application, the multiple- throat venturi system is mounted at the inlet end of the duct having a rectangular cross section of 19 by 14 cm, just upstream of an assembly of inlet screens and flow straighteners that help to suppress undesired flow fluctuations (see Figure 1). The basic venturi measurement principle is well established: One measures the difference in pressure between (1) a point just outside the inlet, where the pressure is highest and the kinetic energy lowest; and (2) the narrowest part (the throat) of the venturi passage, where the kinetic energy is highest and the pressure is lowest. Then by use of Bernoulli s equation for the relationship between pressure and kinetic energy, the volumetric flow speed in the duct can be calculated from the pressure difference and the inlet and throat widths. The design of this system represents a compromise among length, pressure recovery, uniformity of flow, and complexity of assembly. Traditionally, venturis are used to measure faster flows in narrower cross sections, with longer upstream and downstream passages to maintain accuracy. The dimensions of the passages of the present venturi system are sized to provide a readily measurable pressure drop. Multiple throats are used to minimize the length needed to recover internal energy and enable the velocity profile to recover to near flatness.

Bioinspired sensory systems for local flow characterization

NASA Astrophysics Data System (ADS)

Colvert, Brendan; Chen, Kevin; Kanso, Eva

2016-11-01

Empirical evidence suggests that many aquatic organisms sense differential hydrodynamic signals.This sensory information is decoded to extract relevant flow properties. This task is challenging because it relies on local and partial measurements, whereas classical flow characterization methods depend on an external observer to reconstruct global flow fields. Here, we introduce a mathematical model in which a bioinspired sensory array measuring differences in local flow velocities characterizes the flow type and intensity. We linearize the flow field around the sensory array and express the velocity gradient tensor in terms of frame-independent parameters. We develop decoding algorithms that allow the sensory system to characterize the local flow and discuss the conditions under which this is possible. We apply this framework to the canonical problem of a circular cylinder in uniform flow, finding excellent agreement between sensed and actual properties. Our results imply that combining suitable velocity sensors with physics-based methods for decoding sensory measurements leads to a powerful approach for understanding and developing underwater sensory systems.

Flow Control and Measurement in Electric Propulsion Systems: Towards an AIAA Reference Standard

NASA Technical Reports Server (NTRS)

Snyder, John Steven; Baldwin, Jeff; Frieman, Jason D.; Walker, Mitchell L. R.; Hicks, Nathan S.; Polzin, Kurt A.; Singleton, James T.

2013-01-01

Accurate control and measurement of propellant flow to a thruster is one of the most basic and fundamental requirements for operation of electric propulsion systems, whether they be in the laboratory or on flight spacecraft. Hence, it is important for the electric propulsion community to have a common understanding of typical methods for flow control and measurement. This paper addresses the topic of propellant flow primarily for the gaseous propellant systems which have dominated laboratory research and flight application over the last few decades, although other types of systems are also briefly discussed. While most flight systems have employed a type of pressure-fed flow restrictor for flow control, both thermal-based and pressure-based mass flow controllers are routinely used in laboratories. Fundamentals and theory of operation of these types of controllers are presented, along with sources of uncertainty associated with their use. Methods of calibration and recommendations for calibration processes are presented. Finally, details of uncertainty calculations are presented for some common calibration methods and for the linear fits to calibration data that are commonly used.

In vitro flow measurements in ion sputtered hydrocephalus shunts

NASA Technical Reports Server (NTRS)

Cho, Y. I.; Back, L. H.

1989-01-01

This paper describes an experimental procedure for accurate measurements of the pressure-drop/flow rate relationship in hydrocephalus shunts. Using a fish-hook arrangement, small flow rates in a perforated ion-sputtered Teflon microtubule were measured in vitro in a pressured system and were correlated with pressure in the system. Results indicate that appropriate drainage rates could be obtained in the physiological range for hydrocephalus shunts.

LDV measurements in an annular combustor model. M.S. Thesis

NASA Technical Reports Server (NTRS)

Barron, Dean A.

1986-01-01

The design and setup of a Laser Doppler Velocimeter (LDV) system used to take velocity measurements in an annular combustor model are covered. The annular combustor model is of contemporary design using 60 degree flat vane swirlers, producing a strong recirculation zone. Detailed measurements are taken of the swirler inlet air flow and of the downstream enclosed swirling flow. The laser system used is a two color, two component system set up in forward scatter. Detailed are some of the special considerations needed for LDV use in the confined turbulent flow of the combustor model. The LDV measurements in a single swirler rig indicated that the flow changes radically in the first duct height. After this, a flow profile is set up and remains constant in shape. The magnitude of the velocities gradually decays due to viscous damping.

LDV Measurements in an Annular Combustor Model

NASA Technical Reports Server (NTRS)

Barron, Dean A.

1996-01-01

This thesis covers the design and setup of a laser doppler velocimeter (LDV) system used to take velocity measurements in an annular combustor model. The annular combustor model is of contemporary design using 60 degree flat vane swirlers, producing a strong recirculation zone. Detailed measurements are taken of the swirler inlet air flow and of the downstream enclosed swirling flow. The laser system used is a two color, two component system set up in forward scatter. Detailed are some of the special considerations needed for LDV use in the confined turbulent flow of the combustor model. LDV measurements in a single swirler rig indicated that the flow changes radically in the first duct height. After this, a flow profile is set up and remains constant in shape. The magnitude of the velocities gradually decays due to viscous damping.

[A capillary blood flow velocity detection system based on linear array charge-coupled devices].

PubMed

Zhou, Houming; Wang, Ruofeng; Dang, Qi; Yang, Li; Wang, Xiang

2017-12-01

In order to detect the flow characteristics of blood samples in the capillary, this paper introduces a blood flow velocity measurement system based on field-programmable gate array (FPGA), linear charge-coupled devices (CCD) and personal computer (PC) software structure. Based on the analysis of the TCD1703C and AD9826 device data sheets, Verilog HDL hardware description language was used to design and simulate the driver. Image signal acquisition and the extraction of the real-time edge information of the blood sample were carried out synchronously in the FPGA. Then a series of discrete displacement were performed in a differential operation to scan each of the blood samples displacement, so that the sample flow rate could be obtained. Finally, the feasibility of the blood flow velocity detection system was verified by simulation and debugging. After drawing the flow velocity curve and analyzing the velocity characteristics, the significance of measuring blood flow velocity is analyzed. The results show that the measurement of the system is less time-consuming and less complex than other flow rate monitoring schemes.

Macropore system characteristics controls on non-reactive solute transport at different flow rates

NASA Astrophysics Data System (ADS)

Larsbo, Mats; Koestel, John

2014-05-01

Preferential flow and transport in macroporous soils are important pathways for the leaching of agrochemicals through soils. Preferential solute transport in soil is to a large extent determined by the macropore system characteristics and the water flow conditions. The importance of different characteristics of the macropore system is likely to vary with the flow conditions. The objective of this study was to determine which properties of the macropore system that control the shape of non-reactive tracer solute breakthrough curves at different steady-state flow rates. We sampled five undisturbed columns (20 cm high, 20 cm diameter) from the soil surface of four soils with clay contents between 21 and 50 %. Solute transport experiments were carried out under unsaturated conditions at 2, 4, 6, 8 and 12 mm h-1 flow rates. For each flow rate a pulse of potassium bromide solution was applied at the soil surface and the electrical conductivity was measured with high temporal resolution in the column effluent. We used the 5 % arrival time and the holdback factor to estimate the degree of preferential transport from the resulting breakthrough curves. Unsaturated hydraulic conductivities were measured at the soil surface of the columns using a tension disc infiltrometer. The macropore system was imaged by industrial X-ray computed tomography at a resolution of 125 μm in all directions. Measures of the macropore system characteristics including measures of pore continuity were calculated from these images using the ImageJ software. Results show that the degree of preferential transport is generally increasing with flow rate when larger pores become active in the transport. The degree of preferential flow was correlated to measures of macropore topology. This study show that conclusions drawn from experiments carried out at one flow rate should generally not be extrapolated to other flow rates.

A bio-inspired real-time capable artificial lateral line system for freestream flow measurements.

PubMed

Abels, C; Qualtieri, A; De Vittorio, M; Megill, W M; Rizzi, F

2016-06-03

To enhance today's artificial flow sensing capabilities in aerial and underwater robotics, future robots could be equipped with a large number of miniaturized sensors distributed over the surface to provide high resolution measurement of the surrounding fluid flow. In this work we show a linear array of closely separated bio-inspired micro-electro-mechanical flow sensors whose sensing mechanism is based on a piezoresistive strain-gauge along a stress-driven cantilever beam, mimicking the biological superficial neuromasts found in the lateral line organ of fishes. Aiming to improve state-of-the-art flow sensing capability in autonomously flying and swimming robots, our artificial lateral line system was designed and developed to feature multi-parameter freestream flow measurements which provide information about (1) local flow velocities as measured by the signal amplitudes from the individual cantilevers as well as (2) propagation velocity, (3) linear forward/backward direction along the cantilever beam orientation and (4) periodicity of pulses or pulse trains determined by cross-correlating sensor signals. A real-time capable cross-correlation procedure was developed which makes it possible to extract freestream flow direction and velocity information from flow fluctuations. The computed flow velocities deviate from a commercial system by 0.09 m s(-1) at 0.5 m s(-1) and 0.15 m s(-1) at 1.0 m s(-1) flow velocity for a sampling rate of 240 Hz and a sensor distance of 38 mm. Although experiments were performed in air, the presented flow sensing system can be applied to underwater vehicles as well, once the sensors are embedded in a waterproof micro-electro-mechanical systems package.

40 CFR 75.10 - General operating requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... continuous emission monitoring system and a flow monitoring system with an automated data acquisition and handling system for measuring and recording SO2 concentration (in ppm), volumetric gas flow (in scfh), and... emission monitoring system and a flow monitoring system with an automated data acquisition and handling...

Development and testing of highway storm-sewer flow measurement and recording system

USGS Publications Warehouse

Kilpatrick, F.A.; Kaehrle, W.R.; Hardee, Jack; Cordes, E.H.; Landers, M.N.

1985-01-01

A comprehensive study and development of measuring instruments and techniques for measuring all components of flow in a storm-sewer drainage system was undertaken by the U.S. Geological Survey under the sponsorship of the Federal Highway Administration. The study involved laboratory and field calibration and testing of measuring flumes, pipe insert meters, weirs, electromagnetic velocity meters as well as the development and calibration of pneumatic-bubbler pressure transducer head measuring systems. Tracer-dilution and acoustic flow meter measurements were used in field verification tests. A single micrologger was used to record data from all the above instruments as well as from a tipping-bucket rain gage and also to activate on command the electromagnetic velocity meter and tracer-dilution systems. (Author 's abstract)

Multiple-Point Mass Flux Measurement System Using Rayleigh Scattering

NASA Technical Reports Server (NTRS)

Mielke, Amy F.; Elam, Kristie A.; Clem, Michelle M.

2009-01-01

A multiple-point Rayleigh scattering diagnostic is being developed to provide mass flux measurements in gas flows. Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous density, temperature, and velocity measurements. Rayleigh scattered light from a focused 18 Watt continuous-wave laser beam is directly imaged through a solid Fabry-Perot etalon onto a CCD detector which permits spectral analysis of the light. The spatial resolution of the measurements is governed by the locations of interference fringes, which can be changed by altering the etalon characteristics. A prototype system has been used to acquire data in a Mach 0.56 flow to demonstrate feasibility of using this system to provide mass flux measurements. Estimates of measurement uncertainty and recommendations for system improvements are presented

Evaluation of commercially available techniques and development of simplified methods for measuring grille airflows in HVAC systems

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

Walker, Iain S.; Wray, Craig P.; Guillot, Cyril

2003-08-01

In this report, we discuss the accuracy of flow hoods for residential applications, based on laboratory tests and field studies. The results indicate that commercially available hoods are often inadequate to measure flows in residential systems, and that there can be a wide range of performance between different flow hoods. The errors are due to poor calibrations, sensitivity of existing hoods to grille flow non-uniformities, and flow changes from added flow resistance. We also evaluated several simple techniques for measuring register airflows that could be adopted by the HVAC industry and homeowners as simple diagnostics that are often as accuratemore » as commercially available devices. Our test results also show that current calibration procedures for flow hoods do not account for field application problems. As a result, organizations such as ASHRAE or ASTM need to develop a new standard for flow hood calibration, along with a new measurement standard to address field use of flow hoods.« less

Laser Light Scattering Diagnostic for Measurement of Flow Velocity in Vicinity of Propagating Shock Waves

NASA Technical Reports Server (NTRS)

Seasholtz, Richard G.; Buggele, Alvin E.

2002-01-01

A laser light scattering diagnostic for measurement of dynamic flow velocity at a point is described. The instrument is being developed for use in the study of propagating shock waves and detonation waves in pulse detonation engines under development at the NASA Glenn Research Center (GRC). The approach uses a Fabry-Perot interferometer to measure the Doppler shift of laser light scattered from small (submicron) particles in the flow. The high-speed detection system required to resolve the transient response as a shock wave crosses the probe volume uses fast response photodetectors, and a PC based data acquisition system. Preliminary results of measurements made in the GRC Mach 4, 10 by 25 cm supersonic wind tunnel are presented. Spontaneous condensation of water vapor in the flow is used as seed. The tunnel is supplied with continuous air flow at up to 45 psia and the flow is exhausted into the GRC laboratory-wide altitude exhaust system at pressures down to 0.3 psia.

In Vivo Validation of Volume Flow Measurements of Pulsatile Flow Using a Clinical Ultrasound System and Matrix Array Transducer.

PubMed

Hudson, John M; Williams, Ross; Milot, Laurent; Wei, Qifeng; Jago, James; Burns, Peter N

2017-03-01

The goal of this study was to evaluate the accuracy of a non-invasive C-plane Doppler estimation of pulsatile blood flow in the lower abdominal vessels of a porcine model. Doppler ultrasound measurements from a matrix array transducer system were compared with invasive volume flow measurements made on the same vessels with a surgically implanted ultrasonic transit-time flow probe. For volume flow rates ranging from 60 to 750 mL/min, agreement was very good, with a Pearson correlation coefficient of 0.97 (p < 0.0001) and a mean bias of -4.2%. The combination of 2-D matrix array technology and fast processing gives this Doppler method clinical potential, as many of the user- and system-dependent parameters of previous methods, including explicit vessel angle and diameter measurements, are eliminated. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Flow measurements in sewers based on image analysis: automatic flow velocity algorithm.

PubMed

Jeanbourquin, D; Sage, D; Nguyen, L; Schaeli, B; Kayal, S; Barry, D A; Rossi, L

2011-01-01

Discharges of combined sewer overflows (CSOs) and stormwater are recognized as an important source of environmental contamination. However, the harsh sewer environment and particular hydraulic conditions during rain events reduce the reliability of traditional flow measurement probes. An in situ system for sewer water flow monitoring based on video images was evaluated. Algorithms to determine water velocities were developed based on image-processing techniques. The image-based water velocity algorithm identifies surface features and measures their positions with respect to real world coordinates. A web-based user interface and a three-tier system architecture enable remote configuration of the cameras and the image-processing algorithms in order to calculate automatically flow velocity on-line. Results of investigations conducted in a CSO are presented. The system was found to measure reliably water velocities, thereby providing the means to understand particular hydraulic behaviors.

The early indicators of financial failure: a study of bankrupt and solvent health systems.

PubMed

Coyne, Joseph S; Singh, Sher G

2008-01-01

This article presents a series of pertinent predictors of financial failure based on analysis of solvent and bankrupt health systems to identify which financial measures show the clearest distinction between success and failure. Early warning signals are evident from the longitudinal analysis as early as five years before bankruptcy. The data source includes seven years of annual statements filed with the Securities and Exchange Commission by 13 health systems before they filed bankruptcy. Comparative data were compiled from five solvent health systems for the same seven-year period. Seven financial solvency ratios are included in this study, including four cash liquidity measures, two leverage measures, and one efficiency measure. The results show distinct financial trends between solvent and bankrupt health systems, in particular for the operating-cash-flow-related measures, namely Ratio 1: Operating Cash Flow Percentage Change, from prior to current period; Ratio 2: Operating Cash Flow to Net Revenues; and Ratio 4: Cash Flow to Total Liabilities, indicating sensitivity in the hospital industry to cash flow management. The high dependence on credit from third-party payers is cited as a reason for this; thus, there is a great need for cash to fund operations. Five managerial policy implications are provided to help health system managers avoid financial solvency problems in the future.

Demonstration that a new flow sensor can operate in the clinical range for cerebrospinal fluid flow

PubMed Central

Raj, Rahul; Lakshmanan, Shanmugamurthy; Apigo, David; Kanwal, Alokik; Liu, Sheng; Russell, Thomas; Madsen, Joseph R.; Thomas, Gordon A.; Farrow, Reginald C.

2015-01-01

A flow sensor has been fabricated and tested that is capable of measuring the slow flow characteristic of the cerebrospinal fluid in the range from less than 4 mL/h to above 100 mL/h. This sensor is suitable for long-term implantation because it uses a wireless external spectrometer to measure passive subcutaneous components. The sensors are pressure-sensitive capacitors, in the range of 5 pF with an air gap at atmospheric pressure. Each capacitor is in series with an inductor to provide a resonant frequency that varies with flow rate. At constant flow, the system is steady with drift <0.3 mL/h over a month. At variable flow rate, V̇, the resonant frequency, f0, which is in the 200–400 MHz range, follows a second order polynomial with respect to V̇. For this sensor system the uncertainty in measuring f0 is 30 kHz which corresponds to a sensitivity in measuring flow of ΔV̇= 0.6 mL/hr. Pressures up to 20 cm H2O relative to ambient pressure were also measured. An implantable twin capacitor system is proposed that can measure flow, which is fully compensated for all hydrostatic pressures. For twin capacitors, other sources of systematic variation within clinical range, such as temperature and ambient pressure, are smaller than our sensitivity and we delineate a calibration method that should maintain clinically useful accuracy over long times. PMID:26543321

A Mobile System for Measuring Water Surface Velocities Using Unmanned Aerial Vehicle and Large-Scale Particle Image Velocimetry

NASA Astrophysics Data System (ADS)

Chen, Y. L.

2015-12-01

Measurement technologies for velocity of river flow are divided into intrusive and nonintrusive methods. Intrusive method requires infield operations. The measuring process of intrusive methods are time consuming, and likely to cause damages of operator and instrument. Nonintrusive methods require fewer operators and can reduce instrument damages from directly attaching to the flow. Nonintrusive measurements may use radar or image velocimetry to measure the velocities at the surface of water flow. The image velocimetry, such as large scale particle image velocimetry (LSPIV) accesses not only the point velocity but the flow velocities in an area simultaneously. Flow properties of an area hold the promise of providing spatially information of flow fields. This study attempts to construct a mobile system UAV-LSPIV by using an unmanned aerial vehicle (UAV) with LSPIV to measure flows in fields. The mobile system consists of a six-rotor UAV helicopter, a Sony nex5T camera, a gimbal, an image transfer device, a ground station and a remote control device. The activate gimbal helps maintain the camera lens orthogonal to the water surface and reduce the extent of images being distorted. The image transfer device can monitor the captured image instantly. The operator controls the UAV by remote control device through ground station and can achieve the flying data such as flying height and GPS coordinate of UAV. The mobile system was then applied to field experiments. The deviation of velocities measured by UAV-LSPIV of field experiments and handhold Acoustic Doppler Velocimeter (ADV) is under 8%. The results of the field experiments suggests that the application of UAV-LSPIV can be effectively applied to surface flow studies.

A system for calibrating seepage meters used to measure flow between ground water and surface water

USGS Publications Warehouse

Rosenberry, Donald O.; Menheer, Michael A.

2006-01-01

The in-line flowmeter used with this system is incapable of measuring seepage rates below about 7 centimeters per day. Smaller seepage rates can be measured manually. The seepage- control system also can be modified for measuring slower seepage rates with the use of two flowmeters and a slightly different water-routing system, or a fluid-metering pump can be used to control flow through the flux tank instead of an adjustable-height reservoir.

Wide-Area Situational Awareness of Power Grids with Limited Phasor Measurements

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

Zhou, Ning; Huang, Zhenyu; Nieplocha, Jarek

Lack of situational awareness has been identified as one of root causes for the August 14, 2003 Northeast Blackout in North America. To improve situational awareness, the Department of Energy (DOE) launched several projects to deploy Wide Area Measurement Systems (WAMS) in different interconnections. Compared to the tens of thousands of buses, the number of Phasor Measurement Units (PMUs) is quite limited and not enough to achieve the observability for the whole interconnections. To utilize the limited number of PMU measurements to improve situational awareness, this paper proposes to combine PMU measurement data and power flow equations to form amore » hybrid power flow model. Technically, a model which combines the concept of observable islands and modeling of power flow conditions, is proposed. The model is called a Hybrid Power Flow Model as it has both PMU measurements and simulation assumptions, which describes prior knowledge available about whole power systems. By solving the hybrid power flow equations, the proposed method can be used to derive power system states to improve the situational awareness of a power grid.« less

Method and system for measuring multiphase flow using multiple pressure differentials

DOEpatents

Fincke, James R.

2001-01-01

An improved method and system for measuring a multiphase flow in a pressure flow meter. An extended throat venturi is used and pressure of the multiphase flow is measured at three or more positions in the venturi, which define two or more pressure differentials in the flow conduit. The differential pressures are then used to calculate the mass flow of the gas phase, the total mass flow, and the liquid phase. The method for determining the mass flow of the high void fraction fluid flow and the gas flow includes certain steps. The first step is calculating a gas density for the gas flow. The next two steps are finding a normalized gas mass flow rate through the venturi and computing a gas mass flow rate. The following step is estimating the gas velocity in the venturi tube throat. The next step is calculating the pressure drop experienced by the gas-phase due to work performed by the gas phase in accelerating the liquid phase between the upstream pressure measuring point and the pressure measuring point in the venturi throat. Another step is estimating the liquid velocity in the venturi throat using the calculated pressure drop experienced by the gas-phase due to work performed by the gas phase. Then the friction is computed between the liquid phase and a wall in the venturi tube. Finally, the total mass flow rate based on measured pressure in the venturi throat is calculated, and the mass flow rate of the liquid phase is calculated from the difference of the total mass flow rate and the gas mass flow rate.

A multitracer system for multizone ventilation measurement

NASA Astrophysics Data System (ADS)

Sherman, Max

1990-09-01

Mass transfer due to pressure-driven air flow is one of the most important processes for determining both environmental quality and energy requirements in buildings. Heat, moisture, and contaminants are all transported by air movement between indoors and outdoors as well as between different zones within a building. Measurement of these air flows is critical to understanding the performance of buildings. Virtually all measurements of ventilation are made using the dilution of a tracer gas. The vast majority of such measurements have been made in a single zone, using a single tracer gas. For the past several years LBL has been developing the MultiTracer Measurement System (MTMS) to provide full multizone air flow information in an accurate, real-time manner. MTMS is based on a quadrupole mass spectrometer to provide high-speed concentration analysis of multiple tracer gases in the (low) ppm level that are injected into multiple zones using mass-flow controllers. The measurement and injection system is controlled by a PC and can measure all concentrations in all zones (and adjust the injected tracer flows) within 2 min and can operate unattended for weeks. The resulting injection rate and concentration data can be analyzed to infer the bulk air movement between zones. The system also measures related quantities such as weather and zonal temperature to assist in the data interpretation. Using MTMS, field measurements have been made for the past two years.

ASRDI oxygen technology survey. Volume 6: Flow measurement instrumentation

NASA Technical Reports Server (NTRS)

Mann, D. B.

1974-01-01

A summary is provided of information available on liquid and gaseous oxygen flowmetering including an evaluation of commercial meters. The instrument types, physical principles of measurement, and performance characteristics are described. Problems concerning flow measurements of less than plus or minus two percent uncertainty are reviewed. Recommendations concerning work on flow reference systems, the use of surrogate fluids, and standard tests for oxygen flow measurements are also presented.

System and method measuring fluid flow in a conduit

DOEpatents

Ortiz, Marcos German; Kidd, Terrel G.

1999-01-01

A system for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements.

Flow and volume dependence of rat airway resistance during constant flow inflation and deflation.

PubMed

Rubini, Alessandro; Carniel, Emanuele Luigi; Parmagnani, Andrea; Natali, Arturo Nicola

2011-12-01

The aim of this study was to measure the flow and volume dependence of both the ohmic and the viscoelastic pressure dissipations of the normal rat respiratory system separately during inflation and deflation. The study was conducted in the Respiratory Physiology Laboratory in our institution. Measurements were obtained for Seven albino Wistar rats of both sexes by using the flow interruption method during constant flow inflations and deflations. Measurements included anesthesia induction, tracheostomy and positioning of a tracheal cannula, positive pressure ventilation, constant flow respiratory system inflations and deflations at two different volumes and flows. The ohmic resistance exhibited volume and flow dependence, decreasing with lung volume and increasing with flow rate, during both inflation and deflation. The stress relaxation-related viscoelastic resistance also exhibited volume and flow dependence. It decreased with the flow rate at a constant lung volume during both inflation and deflation, but exhibited a different behavior with the lung volume at a constant flow rate (i.e., increased during inflations and decreased during deflations). Thus, stress relaxation in the rat lungs exhibited a hysteretic behavior. The observed flow and volume dependence of respiratory system resistance may be predicted by an equation derived from a model of the respiratory system that consists of two distinct compartments. The equation agrees well with the experimental data and indicates that the loading time is the critical parameter on which stress relaxation depends, during both lung inflation and deflation.

Columbus Payloads Flow Rate Anomalies

NASA Technical Reports Server (NTRS)

Quaranta, Albino; Bufano, Gaetana; DePalo, Savino; Holt, James M.; Szigetvari, Zoltan; Palumberi, Sergio; Hinderer, S.

2011-01-01

The Columbus Active Thermal Control System (ATCS) is the main thermal bus for the pressurized racks working inside the European laboratory. One of the ATCS goals is to provide proper water flow rate to each payload (P/L) by controlling actively the pressure drop across the common plenum distribution piping. Overall flow measurement performed by the Water Pump Assembly (WPA) is the only flow rate monitor available at system level and is not part of the feedback control system. At rack activation the flow rate provided by the system is derived on ground by computing the WPA flow increase. With this approach, several anomalies were raised during these 3 years on-orbit, with the indication of low flow rate conditions on the European racks FSL, BioLab, EDR and EPM. This paper reviews the system and P/Ls calibration approach, the anomalies occurred, the engineering evaluation on the measurement approach and the accuracy improvements proposed, the on-orbit test under evaluation with NASA and finally discusses possible short and long term solutions in case of anomaly confirmation.

Changes in cochlear blood flow in mice due to loud sound exposure measured with Doppler optical microangiography and laser Doppler flowmetry.

PubMed

Reif, Roberto; Zhi, Zhongwei; Dziennis, Suzan; Nuttall, Alfred L; Wang, Ruikang K

2013-10-01

In this work we determined the contributions of loud sound exposure (LSE) on cochlear blood flow (CoBF) in an in vivo anesthetized mouse model. A broadband noise system (20 kHz bandwidth) with an intensity of 119 dB SPL, was used for a period of one hour to produce a loud sound stimulus. Two techniques were used to study the changes in blood flow, a Doppler optical microangiography (DOMAG) system; which can measure the blood flow within individual cochlear vessels, and a laser Doppler flowmetry (LDF) system; which averages the blood flow within a volume (a hemisphere of ~1.5 mm radius) of tissue. Both systems determined that the blood flow within the cochlea is reduced due to the LSE stimulation.

Thermal imaging for cold air flow visualisation and analysis

NASA Astrophysics Data System (ADS)

Grudzielanek, M.; Pflitsch, A.; Cermak, J.

2012-04-01

In this work we present first applications of a thermal imaging system for animated visualization and analysis of cold air flow in field studies. The development of mobile thermal imaging systems advanced very fast in the last decades. The surface temperature of objects, which is detected with long-wave infrared radiation, affords conclusions in different problems of research. Modern thermal imaging systems allow infrared picture-sequences and a following data analysis; the systems are not exclusive imaging methods like in the past. Thus, the monitoring and analysing of dynamic processes became possible. We measured the cold air flow on a sloping grassland area with standard methods (sonic anemometers and temperature loggers) plus a thermal imaging system measuring in the range from 7.5 to 14µm. To analyse the cold air with the thermal measurements, we collected the surface infrared temperatures at a projection screen, which was located in cold air flow direction, opposite the infrared (IR) camera. The intention of using a thermal imaging system for our work was: 1. to get a general idea of practicability in our problem, 2. to assess the value of the extensive and more detailed data sets and 3. to optimise visualisation. The results were very promising. Through the possibility of generating time-lapse movies of the image sequences in time scaling, processes of cold air flow, like flow waves, turbulence and general flow speed, can be directly identified. Vertical temperature gradients and near-ground inversions can be visualised very well. Time-lapse movies will be presented. The extensive data collection permits a higher spatial resolution of the data than standard methods, so that cold air flow attributes can be explored in much more detail. Time series are extracted from the IR data series, analysed statistically, and compared to data obtained using traditional systems. Finally, we assess the usefulness of the additional measurement of cold air flow with thermal imaging systems.

"Time-dependent flow-networks"

NASA Astrophysics Data System (ADS)

Tupikina, Liubov; Molkentin, Nora; Lopez, Cristobal; Hernandez-Garcia, Emilio; Marwan, Norbert; Kurths, Jürgen

2015-04-01

Complex networks have been successfully applied to various systems such as society, technology, and recently climate. Links in a climate network are defined between two geographical locations if the correlation between the time series of some climate variable is higher than a threshold. Therefore, network links are considered to imply information or heat exchange. However, the relationship between the oceanic and atmospheric flows and the climate network's structure is still unclear. Recently, a theoretical approach verifying the correlation between ocean currents and surface air temperature networks has been introduced, where the Pearson correlation networks were constructed from advection-diffusion dynamics on an underlying flow. Since the continuous approach has its limitations, i.e. high computational complexity and fixed variety of the flows in the underlying system, we introduce a new, method of flow-networks for changing in time velocity fields including external forcing in the system, noise and temperature-decay. Method of the flow-network construction can be divided into several steps: first we obtain the linear recursive equation for the temperature time-series. Then we compute the correlation matrix for time-series averaging the tensor product over all realizations of the noise, which we interpret as a weighted adjacency matrix of the flow-network and analyze using network measures. We apply the method to different types of moving flows with geographical relevance such as meandering flow. Analyzing the flow-networks using network measures we find that our approach can highlight zones of high velocity by degree and transition zones by betweenness, while the combination of these network measures can uncover how the flow propagates within time. Flow-networks can be powerful tool to understand the connection between system's dynamics and network's topology analyzed using network measures in order to shed light on different climatic phenomena.

Tracer airflow measurement system (TRAMS)

DOEpatents

Wang, Duo [Albany, CA

2007-04-24

A method and apparatus for measuring fluid flow in a duct is disclosed. The invention uses a novel high velocity tracer injector system, an optional insertable folding mixing fan for homogenizing the tracer within the duct bulk fluid flow, and a perforated hose sampling system. A preferred embodiment uses CO.sub.2 as a tracer gas for measuring air flow in commercial and/or residential ducts. In extant commercial buildings, ducts not readily accessible by hanging ceilings may be drilled with readily plugged small diameter holes to allow for injection, optional mixing where desired using a novel insertable foldable mixing fan, and sampling hose.

An experimental evaluation of the effect of homogenization quality as a preconditioning on oil-water two-phase volume fraction measurement accuracy using gamma-ray attenuation technique

NASA Astrophysics Data System (ADS)

Sharifzadeh, M.; Hashemabadi, S. H.; Afarideh, H.; Khalafi, H.

2018-02-01

The problem of how to accurately measure multiphase flow in the oil/gas industry remains as an important issue since the early 80 s. Meanwhile, oil-water two-phase flow rate measurement has been regarded as an important issue. Gamma-ray attenuation is one of the most commonly used methods for phase fraction measurement which is entirely dependent on the flow regime variations. The peripheral strategy applied for removing the regime dependency problem, is using a homogenization system as a preconditioning tool, as this research work demonstrates. Here, at first, TPFHL as a two-phase flow homogenizer loop has been introduced and verified by a quantitative assessment. In the wake of this procedure, SEMPF as a static-equivalent multiphase flow with an additional capability for preparing a uniform mixture has been explained. The proposed idea in this system was verified by Monte Carlo simulations. Finally, the different water-gas oil two-phase volume fractions fed to the homogenizer loop and injected into the static-equivalent system. A comparison between performance of these two systems by using gamma-ray attenuation technique, showed not only an extra ability to prepare a homogenized mixture but a remarkably increased measurement accuracy for the static-equivalent system.

Development of an outdoor MRI system for measuring flow in a living tree

NASA Astrophysics Data System (ADS)

Nagata, Akiyoshi; Kose, Katsumi; Terada, Yasuhiko

2016-04-01

An outdoor MRI system for noninvasive, long-term measurements of sap flow in a living tree in its natural environment has been developed. An open-access, 0.2 T permanent magnet with a 160 mm gap was combined with a radiofrequency probe, planar gradient coils, electromagnetic shielding, several electrical units, and a waterproofing box. Two-dimensional cross-sectional images were acquired for a ring-porous tree, and the anatomical structures, including xylem and phloem, were identified. The MRI flow measurements demonstrated the diurnal changes in flow velocity in the stem on a per-pixel basis. These results demonstrate that our outdoor MRI system is a powerful tool for studies of water transport in outdoor trees.

In Situ Local Fracture Flow Measurement by the Double Packer Dilution Test

NASA Astrophysics Data System (ADS)

Englert, A.; Le Borgne, T.; Bour, O.; Klepikova, M.; Lavenant, N.

2011-12-01

For prediction of flow and transport in fractured media, prior estimation of the fracture network is essential, but challenging. Recent developments in hydraulic tomography have shown promising results for understanding connectivities between boreholes. However, as the hydraulic tomographic survey is typically based on the propagation of head only, it becomes a strongly non unique problem. To reduce the non uniqueness of tomographic surveys point conditioning has been found beneficial. Just as well, measurement of local flow in a fracture can serve as point conditioning for hydraulic and tracer tomographic surveys. Nevertheless, only few measurements of local fracture flow have been performed since this type of measurements implies several important technical issues. Dilution test in a packed off interval is a possible method for measuring fracture flow (e.g. Drost et al. 1968, Novakowski et al., 2005). However, a key issue for estimating flow with dilution tests is to ensure a full mixing of the tracer in the packed interval. This is typically done by including a mixing system within the packer. The design of such system can be challenging for deep wells and small diameters. Here, we propose a method where mixing is ensured by a recirculation loop including a surface tank. This method is adapted from the design proposed by Brouyere et al. (2008), who measured dilution in open wells. Dilution is quantified by measuring the concentration in the surface barrel as function of time. Together with the measurement of the circulating flow and the water filled volume in the surface barrel, the measured tracer dilution allows for calculation of the fracture flow. Since the method can be applied using a classical double packer system, it may provide a broader application of local flow measurements in heterogeneous media. We tested the approach on the Ploemeur fractured crystalline rock site. A one meter interval at depth 80 m with a single flowing fracture was isolated with a double packer dilution system. We performed a pumping test in the adjacent well. Different flow rates were estimated from the dilution curves for the different pumping rates in the adjacent well, showing a linear response. The obtained fracture flow rates provide important information on the flow geometry and connectivity between the two wells. Future joint interpretation of flow measurements, hydraulic head and tracer test data is expected to provide detailed insights in the flow and transport processes at the Ploemeur site. Drost, W., Klotz, D., Koch, A., Moser, H., Neumaier, F., Rauert, W.: Point dilution methods of investigating ground water flow by means of radioisotopes, Water. Resour. Res., 4(1), 1968. Novakowski, K., Bickerton, G., Lapcevic, P., Voralek, J., Ross, N.: Measurements of groundwater velocity in discrete rock fractures: Jour. Cont. Hydr., 82(1-2), 2006. Brouyere, S., Batlle-Aguilar, J., Goderniaux, P., Dassargues, A.: A new tracer technique for monitoring groundwater fluxes: The Finite Volume Point Dilution Method, Jour. Cont. Hydr., 95(3-4), 121-140, 2008.

Effect of Doppler flow meter position on discharge measurement in surcharged manholes.

PubMed

Yang, Haoming; Zhu, David Z; Liu, Yanchen

2018-02-01

Determining the proper installation location of flow meters is important for accurate measurement of discharge in sewer systems. In this study, flow field and flow regimes in two types of manholes under surcharged flow were investigated using a commercial computational fluid dynamics (CFD) code. The error in measuring the flow discharge using a Doppler flow meter (based on the velocity in a Doppler beam) was then estimated. The values of the corrective coefficient were obtained for the Doppler flow meter at different locations under various conditions. Suggestions for selecting installation positions are provided.

Multiphase fluid characterization system

DOEpatents

Sinha, Dipen N.

2014-09-02

A measurement system and method for permitting multiple independent measurements of several physical parameters of multiphase fluids flowing through pipes are described. Multiple acoustic transducers are placed in acoustic communication with or attached to the outside surface of a section of existing spool (metal pipe), typically less than 3 feet in length, for noninvasive measurements. Sound speed, sound attenuation, fluid density, fluid flow, container wall resonance characteristics, and Doppler measurements for gas volume fraction may be measured simultaneously by the system. Temperature measurements are made using a temperature sensor for oil-cut correction.

The effects of Missouri River mainstem reservoir system operations on 2011 flooding using a Precipitation-Runoff Modeling System model: Chapter K in 2011 Floods of the Central United States

USGS Publications Warehouse

Haj, Adel E.; Christiansen, Daniel E.; Viger, Roland J.

2014-01-01

In 2011 the Missouri River Mainstem Reservoir System (Reservoir System) experienced the largest volume of flood waters since the initiation of record-keeping in the nineteenth century. The high levels of runoff from both snowpack and rainfall stressed the Reservoir System’s capacity to control flood waters and caused massive damage and disruption along the river. The flooding and resulting damage along the Missouri River brought increased public attention to the U.S. Army Corps of Engineers (USACE) operation of the Reservoir System. To help understand the effects of Reservoir System operation on the 2011 Missouri River flood flows, the U.S. Geological Survey Precipitation-Runoff Modeling System was used to construct a model of the Missouri River Basin to simulate flows at streamgages and dam locations with the effects of Reservoir System operation (regulation) on flow removed. Statistical tests indicate that the Missouri River Precipitation-Runoff Modeling System model is a good fit for high-flow monthly and annual stream flow estimation. A comparison of simulated unregulated flows and measured regulated flows show that regulation greatly reduced spring peak flow events, consolidated two summer peak flow events to one with a markedly decreased magnitude, and maintained higher than normal base flow beyond the end of water year 2011. Further comparison of results indicate that without regulation, flows greater than those measured would have occurred and been sustained for much longer, frequently in excess of 30 days, and flooding associated with high-flow events would have been more severe.

Flow prediction over a transport multi-element high-lift system and comparison with flight measurements

NASA Technical Reports Server (NTRS)

Vijgen, P. M. H. W.; Hardin, J. D.; Yip, L. P.

1992-01-01

Accurate prediction of surface-pressure distributions, merging boundary-layers, and separated-flow regions over multi-element high-lift airfoils is required to design advanced high-lift systems for efficient subsonic transport aircraft. The availability of detailed measurements of pressure distributions and both averaged and time-dependent boundary-layer flow parameters at flight Reynolds numbers is critical to evaluate computational methods and to model the turbulence structure for closure of the flow equations. Several detailed wind-tunnel measurements at subscale Reynolds numbers were conducted to obtain detailed flow information including the Reynolds-stress component. As part of a subsonic-transport high-lift research program, flight experiments are conducted using the NASA-Langley B737-100 research aircraft to obtain detailed flow characteristics for support of computational and wind-tunnel efforts. Planned flight measurements include pressure distributions at several spanwise locations, boundary-layer transition and separation locations, surface skin friction, as well as boundary-layer profiles and Reynolds stresses in adverse pressure-gradient flow.

Flow Quality Measurements in the NASA Ames Upgraded 11-by 11-Foot Transonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Amaya, Max A.; Murthy, Sreedhara V.; George, M. W. (Technical Monitor)

2000-01-01

Among the many upgrades designed and implemented in the NASA Ames 11-by 11-Foot Transonic Wind Tunnel over the past few years, several directly affect flow quality in the test section: a turbulence reduction system with a honeycomb and two screens, a flow smoothing system in the back leg diffusers, an improved drive motor control system, and a full replacement set of composite blades for the compressor. Prior to the shut-down of the tunnel for construction activities, an 8-foot span rake populated with flow instrumentation was traversed in the test section to fully document the flow quality and establish a baseline against which the upgrades could be characterized. A similar set of measurements was performed during the recent integrated system test trials, but the scope was somewhat limited in accordance with the primary objective of such tests, namely to return the tunnel to a fully operational status. These measurements clearly revealed substantial improvements in flow angularity and significant reductions in turbulence level for both full-span and semi-span testing configurations, thus making the flow quality of the tunnel one of the best among existing transonic facilities.

System and method measuring fluid flow in a conduit

DOEpatents

Ortiz, M.G.; Kidd, T.G.

1999-05-18

A system is described for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements. 3 figs.

The `Henry Problem' of `density-driven' groundwater flow versus Tothian `groundwater flow systems' with variable density: A review of the influential Biscayne aquifer data.

NASA Astrophysics Data System (ADS)

Weyer, K. U.

2017-12-01

Coastal groundwater flow investigations at the Biscayne Bay, south of Miami, Florida, gave rise to the concept of density-driven flow of seawater into coastal aquifers creating a saltwater wedge. Within that wedge, convection-driven return flow of seawater and a dispersion zone were assumed by Cooper et al. (1964) to be the cause of the Biscayne aquifer `sea water wedge'. This conclusion was based on the chloride distribution within the aquifer and on an analytical model concept assuming convection flow within a confined aquifer without taking non-chemical field data into consideration. This concept was later labelled the `Henry Problem', which any numerical variable density flow program must be able to simulate to be considered acceptable. Both, `density-driven flow' and Tothian `groundwater flow systems' (with or without variable density conditions) are driven by gravitation. The difference between the two are the boundary conditions. 'Density-driven flow' occurs under hydrostatic boundary conditions while Tothian `groundwater flow systems' occur under hydrodynamic boundary conditions. Revisiting the Cooper et al. (1964) publication with its record of piezometric field data (heads) showed that the so-called sea water wedge has been caused by discharging deep saline groundwater driven by gravitational flow and not by denser sea water. Density driven flow of seawater into the aquifer was not found reflected in the head measurements for low and high tide conditions which had been taken contemporaneously with the chloride measurements. These head measurements had not been included in the flow interpretation. The very same head measurements indicated a clear dividing line between shallow local fresh groundwater flow and saline deep groundwater flow without the existence of a dispersion zone or a convection cell. The Biscayne situation emphasizes the need for any chemical interpretation of flow pattern to be supported by head data as energy indicators of flow fields. At the Biscayne site density-driven flow of seawater did and does not exist. Instead this site and the Florida coast line in general are the end points of local fresh and regional saline groundwater flow systems driven by gravity forces and not by density differences.

Self-Calibrating Respiratory-Flowmeter Combination

NASA Technical Reports Server (NTRS)

Westenskow, Dwayne R.; Orr, Joseph A.

1990-01-01

Dual flowmeters ensure accuracy over full range of human respiratory flow rates. System for measurement of respiratory flow employs two flowmeters; one compensates for deficiencies of other. Combination yields easily calibrated system accurate over wide range of gas flow.

Definition of two-phase flow behaviors for spacecraft design

NASA Technical Reports Server (NTRS)

Reinarts, Thomas R.; Best, Frederick R.; Miller, Katherine M.; Hill, Wayne S.

1991-01-01

Two-phase flow, thermal management systems are currently being considered as an alternative to conventional, single phase systems for future space missions because of their potential to reduce overall system mass, size, and pumping power requirements. Knowledge of flow regime transitions, heat transfer characteristics, and pressure drop correlations is necessary to design and develop two-phase systems. A boiling and condensing experiment was built in which R-12 was used as the working fluid. A two-phase pump was used to circulate a freon mixture and allow separate measurements of the vapor and liquid flow streams. The experimental package was flown five times aboard the NASA KC-135 aircraft which simulates zero-g conditions by its parabolic flight trajectory. Test conditions included stratified and annual flow regimes in 1-g which became bubbly, slug, or annular flow regimes on 0-g. A portion of this work is the analysis of adiabatic flow regimes. The superficial velocities of liquid and vapor have been obtained from the measured flow rates and are presented along with the observed flow regimes.

Non-invasive determination of instantaneous brachial blood flow using the oscillometric method.

PubMed

Liu, Shing-Hong; Wang, Jia-Jung; Cheng, Da-Chuan

2009-08-01

The oscillometric method has been widely used to measure arterial systolic and diastolic blood pressures, but its potential for arterial blood flow measurements still remains to be explored. The aim of this study was to non-invasively determine arterial blood flow using an oscillometric blood flow measurement system. The system consists of a pneumatic elastic cuff, an air-pumping motor, a releaser valve, a pressure transducer, and an airflow meter. To build a non-linear cuff model, we measured airflow pumped into the pneumatic cuff and cuff pressure using an airflow meter and pressure transducer during the inflation period, respectively. During the deflation period, only the pressure transducer was used to record cuff pressure. Based on the cuff model, the oscillometric blood flow waveform was obtained by integrating the oscillometric pressure waveform. We compared arterial blood flow derived from the maximum amplitude of the oscillometric blood flow waveform with Doppler-measured blood flow calculated with the diameters and blood velocities of the brachial arteries in 32 subjects who underwent diagnostic evaluations for peripheral arterial embolism. A linear correlation coefficient of r = 0.716 was found between the oscillometry- and Doppler-based blood flow measurements in the 32 subjects. These results suggest that blood flow passing through the brachial artery can be quantified non-invasively using the oscillometric approach after appropriate calibration.

Systems and Sensors for Debris-flow Monitoring and Warning

PubMed Central

Arattano, Massimo; Marchi, Lorenzo

2008-01-01

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 non-structural 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, trip wires etc. Event warning systems for debris flows have a strong linkage with debris-flow monitoring that is carried out for research purposes: the same sensors are often used for both monitoring and warning, although warning systems have higher requirements of robustness than monitoring systems. The paper presents a description of the sensors employed for debris-flow monitoring and event warning systems, with attention given to advantages and drawbacks of different types of sensors. PMID:27879828

Design and implementation of a smartphone-based portable ultrasound pulsed-wave Doppler device for blood flow measurement.

PubMed

Huang, Chih-Chung; Lee, Po-Yang; Chen, Pay-Yu; Liu, Ting-Yu

2012-01-01

Blood flow measurement using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological monitor. Recently, pocket-sized ultrasound scanners have been introduced for portable diagnosis. The present paper reports the implementation of a portable ultrasound pulsed-wave (PW) Doppler flowmeter using a smartphone. A 10-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional baseband Doppler shift signals were obtained using a portable analog circuit system. After hardware processing, the Doppler signals were fed directly to a smartphone for Doppler spectrogram analysis and display in real time. To the best of our knowledge, this is the first report of the use of this system for medical ultrasound Doppler signal processing. A Couette flow phantom, consisting of two parallel disks with a 2-mm gap, was used to evaluate and calibrate the device. Doppler spectrograms of porcine blood flow were measured using this stand-alone portable device under the pulsatile condition. Subsequently, in vivo portable system verification was performed by measuring the arterial blood flow of a rat and comparing the results with the measurement from a commercial ultrasound duplex scanner. All of the results demonstrated the potential for using a smartphone as a novel embedded system for portable medical ultrasound applications. © 2012 IEEE

Device and method for measuring fluid flow in a conduit having a gradual bend

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1998-11-10

A system is described for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend

DOEpatents

Ortiz, M.G.

1998-02-10

A system is described for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Device and method for measuring multi-phase fluid flow and density of fluid in a conduit having a gradual bend

DOEpatents

Ortiz, Marcos German; Boucher, Timothy J.

1998-01-01

A system for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Device and method for measuring fluid flow in a conduit having a gradual bend

DOEpatents

Ortiz, Marcos German; Boucher, Timothy J

1998-01-01

A system for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend

DOEpatents

Ortiz, Marcos German

1998-01-01

A system for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

The characterisation and application of a pulsed neodymium YAG laser DGV system to a time-varying high-speed flow

NASA Astrophysics Data System (ADS)

Thorpe, S. J.; Quinlan, N.; Ainsworth, R. W.

2000-10-01

Doppler Global Velocimetry (DGV) is a whole-field measurement technique which has attracted significant interest from the fluid-flow research community since its introduction in 1991. Practical implementations of the methodology have focused on two principal laser light sources: the argon ion laser, applied to steady state or slowly varying flows; and the pulsed neodymium YAG laser for the measurement of instantaneous velocity fields. However, the emphasis in the published literature has been very much on research using the argon laser. This paper reports the application of a Q-switched, injection-seeded neodymium YAG laser to the proven Oxford DGV system, and the use of this combination in a short duration unsteady high-speed flow. The pertinent characteristics of the apparatus are described, and the impact of these on the integrity of the resulting velocity measurements is presented. Adaptations to the commercial laser system that make it suitable for application to the measurement of transient high-speed flows are described. Finally, the application of this system to a short duration unsteady flow is described. This application is based on the flow found in a new type of transdermal drug delivery device, where particles of the drug material are projected at high speed through the skin. Whole-field velocities are recorded, and values as high as 800 m/ s are evident.

Miniaturized Water Flow and Level Monitoring System for Flood Disaster Early Warning

NASA Astrophysics Data System (ADS)

Ifedapo Abdullahi, Salami; Hadi Habaebi, Mohamed; Surya Gunawan, Teddy; Rafiqul Islam, MD

2017-11-01

This study presents the performance of a prototype miniaturised water flow and water level monitoring sensor designed towards supporting flood disaster early warning systems. The design involved selection of sensors, coding to control the system mechanism, and automatic data logging and storage. During the design phase, the apparatus was constructed where all the components were assembled using locally sourced items. Subsequently, under controlled laboratory environment, the system was tested by running water through the inlet during which the flow rate and rising water levels are automatically recorded and stored in a database via Microsoft Excel using Coolterm software. The system is simulated such that the water level readings measured in centimeters is output in meters using a multiplicative of 10. A total number of 80 readings were analyzed to evaluate the performance of the system. The result shows that the system is sensitive to water level rise and yielded accurate measurement of water level. But, the flow rate fluctuates due to the manual water supply that produced inconsistent flow. It was also observed that the flow sensor has a duty cycle of 50% of operating time under normal condition which implies that the performance of the flow sensor is optimal.

Wind Tunnel Seeding Systems for Laser Velocimeters

NASA Technical Reports Server (NTRS)

Hunter, W. W., Jr. (Compiler); Nichols, C. E., Jr. (Compiler)

1985-01-01

The principal motivating factor for convening the Workshop on the Development and Application of Wind Tunnel Seeding Systems for Laser Velocimeters is the necessity to achieve efficient operation and, most importantly, to insure accurate measurements with velocimeter techniques. The ultimate accuracy of particle scattering based laser velocimeter measurements of wind tunnel flow fields depends on the ability of the scattering particle to faithfully track the local flow field in which it is embedded. A complex relationship exists between the particle motion and the local flow field. This relationship is dependent on particle size, size distribution, shape, and density. To quantify the accuracy of the velocimeter measurements of the flow field, the researcher has to know the scattering particle characteristics. In order to obtain optimum velocimeter measurements, the researcher is striving to achieve control of the particle characteristics and to verify those characteristics at the measurement point. Additionally, the researcher is attempting to achieve maximum measurement efficiency through control of particle concentration and location in the flow field.

Optical Air Flow Measurements in Flight

NASA Technical Reports Server (NTRS)

Bogue, Rodney K.; Jentink, Henk W.

2004-01-01

This document has been written to assist the flight-test engineer and researcher in using optical flow measurements in flight applications. The emphasis is on describing tradeoffs in system design to provide desired measurement performance as currently understood. Optical system components are discussed with examples that illustrate the issues. The document concludes with descriptions of optical measurement systems designed for a variety of applications including aeronautics research, airspeed measurement, and turbulence hazard detection. Theoretical discussion is minimized, but numerous references are provided to supply ample opportunity for the reader to understand the theoretical underpinning of optical concepts.

Determination of Heritage SSME Pogo Suppressor Resistance and Inertance from Waterflow Pulse Testing

NASA Technical Reports Server (NTRS)

McDougal, Chris; Eberhart, Chad; Lee, Erik

2016-01-01

Waterflow tests of a heritage Space Shuttle Main Engine pogo suppressor were performed to experimentally quantify the resistance and inertance provided by the suppressor. Measurements of dynamic pressure and flow rate in response to pulsing flow were made throughout the test loop. A unique system identification methodology combined all sensor measurements with a one-dimensional perturbational flow model of the complete water flow loop to spatially translate physical measurements to the device under test. Multiple techniques were then employed to extract the effective resistance and inertance for the pogo suppressor. Parameters such as steady flow rate, perturbational flow rate magnitude, and pulse frequency were investigated to assess their influence on the behavior of the pogo suppressor dynamic response. These results support validation of the RS-25 pogo suppressor performance for use on the Space Launch System Core Stage.

Phased Array Ultrasound System for Planar Flow Mapping in Liquid Metals.

PubMed

Mader, Kevin; Nauber, Richard; Galindo, Vladimir; Beyer, Hannes; Buttner, Lars; Eckert, Sven; Czarske, Jurgen

2017-09-01

Controllable magnetic fields can be used to optimize flows in technical and industrial processes involving liquid metals in order to improve quality and yield. However, experimental studies in magnetohydrodynamics often involve complex, turbulent flows and require planar, two-component (2c) velocity measurements through only one acoustical access. We present the phased array ultrasound Doppler velocimeter as a modular research platform for flow mapping in liquid metals. It combines the pulse wave Doppler method with the phased array technique to adaptively focus the ultrasound beam. This makes it possible to resolve smaller flow structures in planar measurements compared with fixed-beam sensors and enables 2c flow mapping with only one acoustical access via the cross beam technique. From simultaneously measured 2-D velocity fields, quantities for turbulence characterization can be derived. The capabilities of this measurement system are demonstrated through measurements in the alloy gallium-indium-tin at room temperature. The 2-D, 2c velocity measurements of a flow in a cubic vessel driven by a rotating magnetic field (RMF) with a spatial resolution of up to 2.2 mm are presented. The measurement results are in good agreement with a semianalytical simulation. As a highlight, two-point correlation functions of the velocity field for different magnitudes of the RMF are presented.

40 CFR 1065.245 - Sample flow meter for batch sampling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... rates or total flow sampled into a batch sampling system over a test interval. You may use the... rates or total raw exhaust flow over a test interval. (b) Component requirements. We recommend that you... averaging Pitot tube, or a hot-wire anemometer. Note that your overall system for measuring sample flow must...

Laser Doppler dust devil measurements

NASA Technical Reports Server (NTRS)

Bilbro, J. W.; Jeffreys, H. B.; Kaufman, J. W.; Weaver, E. A.

1977-01-01

A scanning laser doppler velocimeter (SLDV) system was used to detect, track, and measure the velocity flow field of naturally occurring tornado-like flows (dust devils) in the atmosphere. A general description of the dust devil phenomenon is given along with a description of the test program, measurement system, and data processing techniques used to collect information on the dust devil flow field. The general meteorological conditions occurring during the test program are also described, and the information collected on two selected dust devils are discussed in detail to show the type of information which can be obtained with a SLDV system. The results from these measurements agree well with those of other investigators and illustrate the potential for the SLDV in future endeavors.

Initial testing of a 3D printed perfusion phantom using digital subtraction angiography

NASA Astrophysics Data System (ADS)

Wood, Rachel P.; Khobragade, Parag; Ying, Leslie; Snyder, Kenneth; Wack, David; Bednarek, Daniel R.; Rudin, Stephen; Ionita, Ciprian N.

2015-03-01

Perfusion imaging is the most applied modality for the assessment of acute stroke. Parameters such as Cerebral Blood Flow (CBF), Cerebral Blood volume (CBV) and Mean Transit Time (MTT) are used to distinguish the tissue infarct core and ischemic penumbra. Due to lack of standardization these parameters vary significantly between vendors and software even when provided with the same data set. There is a critical need to standardize the systems and make them more reliable. We have designed a uniform phantom to test and verify the perfusion systems. We implemented a flow loop with different flow rates (250, 300, 350 ml/min) and injected the same amount of contrast. The images of the phantom were acquired using a Digital Angiographic system. Since this phantom is uniform, projection images obtained using DSA is sufficient for initial validation. To validate the phantom we measured the contrast concentration at three regions of interest (arterial input, venous output, perfused area) and derived time density curves (TDC). We then calculated the maximum slope, area under the TDCs and flow. The maximum slope calculations were linearly increasing with increase in flow rate, the area under the curve decreases with increase in flow rate. There was 25% error between the calculated flow and measured flow. The derived TDCs were clinically relevant and the calculated flow, maximum slope and areas under the curve were sensitive to the measured flow. We have created a systematic way to calibrate existing perfusion systems and assess their reliability.

Dynamic PIV measurement of a compressible flow issuing from an airbag inflator nozzle

NASA Astrophysics Data System (ADS)

Lee, Sang Joon; Jang, Young Gil; Kim, Seok; Kim, Chang Soo

2006-12-01

Among many equipment for passenger safety, the air bag system is the most fundamental and effective device for an automobile. The inflator housing is a main part of the curtain-type air bag system, which supplies high-pressure gases in pumping up the air bag-curtain which is increasingly being adapted in deluxe cars for protecting passengers from the danger of side clash. However, flow information on the inflator housing is very limited. In this study, we measure the instantaneous velocity fields of a high-speed compressible flow issuing from the exit nozzle of an inflator housing using a dynamic PIV system. From the velocity field data measured at a high frame-rate, we evaluate the variation of the mass flow rate with time. The dynamic PIV system consists of a high-repetition Nd:YLF laser, a high-speed CMOS camera, and a delay generator. The flow images are taken at 4000 fps with synchronization of the trigger signal for inflator ignition. From the instantaneous velocity field data of flow ejecting from the airbag inflator housing at the initial stage, we can see a flow pattern of broken shock wave front and its downward propagation. The flow ejecting from the inflator housing is found to have very high velocity fluctuations, with the maximum velocity at about 700 m/s. The time duration of the high-speed flow is very short, and there is no perceptible flow after 100 ms.

Flow of sand and a variable mass Atwood machine

NASA Astrophysics Data System (ADS)

Flores, José; Solovey, Guillermo; Gil, Salvador

2003-07-01

We discuss a simple and inexpensive apparatus that lets us measure the instantaneous flow rate of granular media, such as sand, in real time. The measurements allow us to elucidate the phenomenological laws that govern the flow of granular media through an aperture. We use this apparatus to construct a variable mass system and study the motion of an Atwood machine with one weight changing in time in a controlled manner. The study illustrates Newton's second law for variable mass systems and lets us investigate the dependence of the flow rate on acceleration.

Quantifying radar-rainfall uncertainties in urban drainage flow modelling

NASA Astrophysics Data System (ADS)

Rico-Ramirez, M. A.; Liguori, S.; Schellart, A. N. A.

2015-09-01

This work presents the results of the implementation of a probabilistic system to model the uncertainty associated to radar rainfall (RR) estimates and the way this uncertainty propagates through the sewer system of an urban area located in the North of England. The spatial and temporal correlations of the RR errors as well as the error covariance matrix were computed to build a RR error model able to generate RR ensembles that reproduce the uncertainty associated with the measured rainfall. The results showed that the RR ensembles provide important information about the uncertainty in the rainfall measurement that can be propagated in the urban sewer system. The results showed that the measured flow peaks and flow volumes are often bounded within the uncertainty area produced by the RR ensembles. In 55% of the simulated events, the uncertainties in RR measurements can explain the uncertainties observed in the simulated flow volumes. However, there are also some events where the RR uncertainty cannot explain the whole uncertainty observed in the simulated flow volumes indicating that there are additional sources of uncertainty that must be considered such as the uncertainty in the urban drainage model structure, the uncertainty in the urban drainage model calibrated parameters, and the uncertainty in the measured sewer flows.

Measurement uncertainty budget of an interferometric flow velocity sensor

NASA Astrophysics Data System (ADS)

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 measurement uncertainty budget of the sensor is discussed. Finally, generated measurement results for the film flow of an impinging jet cleaning experiment are presented.

An automated cell analysis sensing system based on a microfabricated rheoscope for the study of red blood cells physiology.

PubMed

Bransky, Avishay; Korin, Natanel; Nemirovski, Yael; Dinnar, Uri

2006-08-15

An automated rheoscope has been developed, utilizing a microfabricated glass flow cell, high speed camera and advanced image-processing software. RBCs suspended in a high viscosity medium were filmed flowing through a microchannel. Under these conditions, RBCs exhibit different orientations and deformations according to their location in the velocity profile. The rheoscope system produces valuable data such as velocity profile of RBCs, spatial distribution within a microchannel and deformation index (DI) curves. The variation of DI across the channel height, due to change in shear stress, was measured carrying implications for diffractometry methods. These curves of DI were taken at a constant flow rate and cover most of the relevant shear stress spectrum. This is an improvement of the existing techniques for deformability measurements and may serve as a diagnostic tool for certain blood disorders. The DI curves were compared to measurements of the flowing RBCs velocity profile. In addition, we found that RBCs flowing in a microchannel are mostly gathered in the center of the flow and maintain a characteristic spatial distribution. The spatial distribution in this region changes slightly with increasing flow rate. Hence, the system described, provides means for examining the behavior of individual RBCs, and may serve as a microfabricated diagnostic device for deformability measurement.

A diameter-sensitive flow entropy method for reliability consideration in water distribution system design

NASA Astrophysics Data System (ADS)

Liu, Haixing; Savić, Dragan; Kapelan, Zoran; Zhao, Ming; Yuan, Yixing; Zhao, Hongbin

2014-07-01

Flow entropy is a measure of uniformity of pipe flows in water distribution systems. By maximizing flow entropy one can identify reliable layouts or connectivity in networks. In order to overcome the disadvantage of the common definition of flow entropy that does not consider the impact of pipe diameter on reliability, an extended definition of flow entropy, termed as diameter-sensitive flow entropy, is proposed. This new methodology is then assessed by using other reliability methods, including Monte Carlo Simulation, a pipe failure probability model, and a surrogate measure (resilience index) integrated with water demand and pipe failure uncertainty. The reliability assessment is based on a sample of WDS designs derived from an optimization process for each of the two benchmark networks. Correlation analysis is used to evaluate quantitatively the relationship between entropy and reliability. To ensure reliability, a comparative analysis between the flow entropy and the new method is conducted. The results demonstrate that the diameter-sensitive flow entropy shows consistently much stronger correlation with the three reliability measures than simple flow entropy. Therefore, the new flow entropy method can be taken as a better surrogate measure for reliability and could be potentially integrated into the optimal design problem of WDSs. Sensitivity analysis results show that the velocity parameters used in the new flow entropy has no significant impact on the relationship between diameter-sensitive flow entropy and reliability.

Design and analysis on fume exhaust system of blackbody cavity sensor for continuously measuring molten steel temperature

NASA Astrophysics Data System (ADS)

Mei, Guohui; Zhang, Jiu; Zhao, Shumao; Xie, Zhi

2017-03-01

Fume exhaust system is the main component of the novel blackbody cavity sensor with a single layer tube, which removes the fume by gas flow along the exhaust pipe to keep the light path clean. However, the gas flow may break the conditions of blackbody cavity and results in the poor measurement accuracy. In this paper, we analyzed the influence of the gas flow on the temperature distribution of the measuring cavity, and then calculated the integrated effective emissivity of the non-isothermal cavity based on Monte-Carlo method, accordingly evaluated the sensor measurement accuracy, finally obtained the maximum allowable flow rate for various length of the exhaust pipe to meet the measurement accuracy. These results will help optimize the novel blackbody cavity sensor design and use it better for measuring the temperature of molten steel.

Device and method for measuring multi-phase fluid flow and density of fluid in a conduit having a gradual bend

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1998-10-27

A system is described for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Molecular-Flow Properties of RIB Type Vapor-Transport Systems Using a Fast-Valve

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

Alton, Gerald D; Bilheux, Hassina Z; Zhang, Y.

2014-01-01

The advent of the fast-valve device, described previously, permits measurement of molecular-flow times of chemically active or inactive gaseous species through radioactive ion beam (RIB) target ion source systems, independent of size, geometry and materials of construction. Thus, decay losses of short-half-life RIBs can be determined for a given target/vapor-transport system in advance of on-line operation, thereby ascertaining the feasibility of the system design for successful processing of a given isotope. In this article, molecular-flow-time theory and experimentally measured molecular-flow time data are given for serial- and parallel-coupled Ta metal RIB vapor-transport systems similar to those used at ISOL basedmore » RIB facilities. In addition, the effect of source type on the molecular-flow time properties of a given system is addressed, and a chemical passivation method for negating surface adsorption enthalpies for chemically active gaseous species on Ta surfaces is demonstrated.« less

STORM-SEWER FLOW MEASUREMENT AND RECORDING SYSTEM.

USGS Publications Warehouse

Kilpatrick, Frederick A.; Kaehrle, William R.

1986-01-01

A comprehensive study and development of instruments and techniques for measuring all components of flow in a storm-sewer drainage system were undertaken by the U. S. Geological Survey under the sponsorship of FHWA. The study involved laboratory and field calibration and testing of measuring flumes, pipe insert meters, weirs, and electromagnetic velocity meters as well as the development and calibration of pneumatic bubbler and pressure transducer head-measuring systems. Tracer dilution and acoustic-flowmeter measurements were used in field verification tests. A single micrologger was used to record data from all the instruments and also to activate on command the electromagnetic velocity meter and tracer dilution systems.

Advancements in Dual-Pump Broadband CARS for Supersonic Combustion Measurements

NASA Technical Reports Server (NTRS)

Tedder, Sarah Augusta Umberger

2010-01-01

Space- and time-resolved measurements of temperature and species mole fractions of nitrogen, oxygen, and hydrogen were obtained with a dual-pump coherent anti-Stokes Raman spectroscopy (CARS) system in hydrogen-fueled supersonic combustion free jet flows. These measurements were taken to provide time-resolved fluid properties of turbulent supersonic combustion for use in the creation and verification of computational fluid dynamic (CFD) models. CFD models of turbulent supersonic combustion flow currently facilitate the design of air-breathing supersonic combustion ramjet (scramjet) engines. Measurements were made in supersonic axi-symmetric free jets of two scales. First, the measurement system was tested in a laboratory environment using a laboratory-scale burner (approx.10 mm at nozzle exit). The flow structures of the laboratory-burner were too small to be resolved with the CARS measurements volume, but the composition and temperature of the jet allowed the performance of the system to be evaluated. Subsequently, the system was tested in a burner that was approximately 6 times larger, whose length scales are better resolved by the CARS measurement volume. During both these measurements, weaknesses of the CARS system, such as sensitivity to vibrations and beam steering and inability to measure temperature or species concentrations in hydrogen fuel injection regions were indentified. Solutions were then implemented in improved CARS systems. One of these improved systems is a dual-pump broadband CARS technique called, Width Increased Dual-pump Enhanced CARS (WIDECARS). The two lowest rotational energy levels of hydrogen detectable by WIDECARS are H2 S(3) and H2 S(4). The detection of these lines gives the system the capability to measure temperature and species concentrations in regions of the flow containing pure hydrogen fuel at room temperature. WIDECARS is also designed for measurements of all the major species (except water) in supersonic combustion flows fueled with hydrogen and hydrogen/ethylene mixtures (N2, O2, H2, C2H4, CO, and CO2). This instrument can characterize supersonic combustion fueled with surrogate fuel mixtures of hydrogen and ethylene. This information can lead to a better understanding of the chemistry and performance of supersonic combustion fueled with cracked jet propulsion (JP)-type fuel.

Development of an aerodynamic measurement system for hypersonic rarefied flows

NASA Astrophysics Data System (ADS)

Ozawa, T.; Fujita, K.; Suzuki, T.

2015-01-01

A hypersonic rarefied wind tunnel (HRWT) has lately been developed at Japan Aerospace Exploration Agency in order to improve the prediction of rarefied aerodynamics. Flow characteristics of hypersonic rarefied flows have been investigated experimentally and numerically. By conducting dynamic pressure measurements with pendulous models and pitot pressure measurements, we have probed flow characteristics in the test section. We have also improved understandings of hypersonic rarefied flows by integrating a numerical approach with the HRWT measurement. The development of the integration scheme between HRWT and numerical approach enables us to estimate the hypersonic rarefied flow characteristics as well as the direct measurement of rarefied aerodynamics. Consequently, this wind tunnel is capable of generating 25 mm-core flows with the free stream Mach number greater than 10 and Knudsen number greater than 0.1.

Chemical preconcentrator with integral thermal flow sensor

DOEpatents

Manginell, Ronald P.; Frye-Mason, Gregory C.

2003-01-01

A chemical preconcentrator with integral thermal flow sensor can be used to accurately measure fluid flow rate in a microanalytical system. The thermal flow sensor can be operated in either constant temperature or constant power mode and variants thereof. The chemical preconcentrator with integral thermal flow sensor can be fabricated with the same MEMS technology as the rest of the microanlaytical system. Because of its low heat capacity, low-loss, and small size, the chemical preconcentrator with integral thermal flow sensor is fast and efficient enough to be used in battery-powered, portable microanalytical systems.

Measurements in the Turbulent Boundary Layer at Constant Pressure in Subsonic and Supersonic Flow. Part I. Mean Flow

DTIC Science & Technology

1978-05-01

distribution unlimited. I REPORTS ":-- r , Prepared for ARNOLD ENGINEERING DEVELOPMENT CENTER/DOTR AiR FORCE SYSTEMS COMMAND ARNOLD AIR FORCE STATIONI...section and diffuser. The measurements used the JPL multlport measuring system , which simultaneously recorded the stag- nation temperature and...stagnation and static pressures were recorded by the data system . For. the experiments.at CIT, two techniques were employed. Within the first i00 cm from

Developing an ultrasound correlation velocimetry system

NASA Astrophysics Data System (ADS)

Surup, Gerrit; White, Christopher; UNH Team

2011-11-01

The process of building an ultrasound correlation velocimetry (UCV) system by integrating a commercial medical ultrasound with a PC running commercial PIV software is described and preliminary validation measurements in pipe flow using UCV and optical particle image velocimetry (PIV) are reported. In principles of operation, UCV is similar to the technique of PIV, differing only in the image acquisition process. The benefits of UCV are that it does not require optical access to the flow field and can be used for measuring flows of opaque fluids. While the limitations of UVC are the inherently low frame rates (limited by the imaging capabilities of the commercial ultrasound system) and low spatial resolution, which limits the range of velocities and transient flow behavior that can be measured. The support of the NSF (CBET0846359, grant monitor Horst Henning Winter) is gratefully acknowledged.

NEW MODEL AND MEASUREMENT PRINCIPLE OF FLOWING AND HEAT TRANSFER CHARACTERISTICS OF REGENERATOR

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

Chen, Y. Y.; Graduate University of the Chinese Academy of Sciences, Beijing, 100049; Luo, E. C.

2008-03-16

Regenerators play key role in oscillating-flow cryocoolers or thermoacoustic heat engine systems. However, their flowing and heat transfer mechanism is still not well understood. The complexities of the oscillating flow regenerator make traditional method of heat transfer research become difficult or helpless. In this paper, a model for porous media regenerator was given based on the linear thermoacoustic theory. Then the correlations for characteristic parameters were obtained by deducing universal expressions for thermoacoustic viscous function F{sub v} and thermal function F{sub T}. A simple acoustical method and experimental system to get F{sub v} and F{sub T} via measurements of isothermalmore » regenerators were presented. Some measurements of packed stainless screen regenerators were performed, and preliminary experimental results for flow and convective coefficients were derived, which showing flowing friction factor is approximately within 132/Re to 173/Re.« less

A Microfluidics-based Pulpal Arteriole Blood Flow Phantom for Validation of Doppler Ultrasound Devices in Pulpal Blood Flow Velocity Measurement.

PubMed

Kim, Dohyun; Park, Sung-Ho

2016-11-01

Recently, Doppler ultrasound has been used for the measurement of pulpal blood flow in human teeth. However, the reliability of this method has not been verified. In this study, we developed a model to simulate arteriole blood flow within the dental pulp by using microfluidics. This arteriole simulator, or flow phantom, was used to determine the reliability of measurements obtained by using a Doppler ultrasound device. A microfluidic chip was fabricated by using the soft lithography technique, and blood-mimicking fluid was pumped through the channel by a microfluidic system. A Doppler ultrasound device was used for the measurement of flow velocity. The peak, mean, and minimal flow velocities obtained from the phantom and the Doppler ultrasound device were compared by using linear regression analysis and Pearson correlation coefficient. Bland-Altman analyses were performed to evaluate the velocity differences between the flow generated by the phantom and the flow measurements made with the Doppler ultrasound device. The microfluidic system was able to generate the flow profiles as intended, and the fluid flow could be monitored and controlled by the software program. There were excellent linear correlations between the peak, mean, and minimal flow velocities of the phantom and those of the Doppler ultrasound device (r = 0.94-0.996, P < .001). However, the velocities were overestimated by the Doppler ultrasound device. This phantom provides opportunities for research and education involving the Doppler ultrasound technique in dentistry. Although Doppler ultrasound can be an effective tool for the measurement of pulpal blood flow velocity, it is essential to validate and calibrate the device before clinical use. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Data system for multiplexed water-current meters

NASA Technical Reports Server (NTRS)

Ramsey, C. R.

1977-01-01

Flow rates at 32 flood plain locations are measured simultaneously by single digital logic unit with high noise immunity. Water flowing through pygmy current meters rotates element that closes electrical contact once every resolution, so flow rate is measured by counting number of closures in time interval.

An experimental investigation on fluid dynamics of an automotive torque converter

NASA Astrophysics Data System (ADS)

Dong, Yu

The objective of the automotive torque converter fluid dynamics experimental investigation is to understand the flow field inside the torque converter, improve the performance, and increase the fuel economy of vehicles. A high-frequency response five-hole probe was developed for the unsteady flow measurement. The dynamic performance of this probe was examined, and the corresponding data processing technique was also developed. The accuracy of this probe unsteady flow measurement was assessed using a hot-film sensor and a high-frequency response total pressure Pitot probe. The pump passage relative flow field was measured by a rotating five-hole probe system at three chord-wise locations. The rotating probe system is designed and developed for both pump and turbine flow measurement, and it was proved to be accurate and successful. A strong secondary flow is observed to dominate the flow structure at the pump mid-chord. At the pump 3/4 chord, the flow concentration on the pressure side is clearly observed. The secondary flow is found to change direction of rotation between the 3/4 chord and the 4/4 chord. High losses are found in the core-suction corner "wake" flow. The pump exit and turbine exit unsteady flow fields were measured by a high-frequency response five-hole probe in the stationary frame. At the pump exit, the flow is concentrated on the pressure side due to the strong secondary flow in the pump passage. A strong secondary flow is observed. At the turbine exit, a fully developed flow is found caused by the turbulent mixing. The stator exit steady flow was measured by a conventional five-hole probe. A strong secondary flow is found due to the inlet vorticity and axial velocity deficit near the core. The radially inward velocity and the secondary flow produce a large radial transport of mass flow in the stator passage. The stator passage flow is found to be turbulent at the normal operating condition by the measurement using the surface hot-film sensors mounted on the stator blade surface. Based on the experimental data and analysis, recommendations are proposed for the hydraulic design and the fluid dynamics research of the torque converter.

40 CFR 86.210-08 - Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... detector (HFID) (375 °±20 °F (191 °±11 °C)) sample for total hydrocarbon (THC) analysis. The HFID sample... integrated measurement of diluted THC is required. Unless compensation for varying mass flow is made, a constant mass flow system must be used to ensure a proportional THC measurement. (2) For natural gas-fueled...

40 CFR 86.210-08 - Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... detector (HFID) (375 °±20 °F (191 °±11 °C)) sample for total hydrocarbon (THC) analysis. The HFID sample... integrated measurement of diluted THC is required. Unless compensation for varying mass flow is made, a constant mass flow system must be used to ensure a proportional THC measurement. (2) For natural gas-fueled...

A simple bubble-flowmeter with quasicontinuous registration.

PubMed

Ludt, H; Herrmann, H D

1976-07-22

The construction of a simple bubble-flow-meter is described. The instrument has the following features: 1. automatic bubble injection, 2. precise measurement of the bubble passage time by a digital counter, 3. quasicontinuous registration of the flow rate, 4. alternative run with clear fluid (water) and coloured fluid (blood), 5. low volume, 6. closed measuring system for measurements in low and high pressure systems.

Laser induced fluorescence measurements of ion velocity and temperature of drift turbulence driven sheared plasma flow in a linear helicon plasma device

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

Chakraborty Thakur, S.; Fedorczak, N.; Manz, P.

2012-08-15

Using laser induced fluorescence (LIF), radial profiles of azimuthal ion fluid velocity and ion temperature are measured in the controlled shear de-correlation experiment (CSDX) linear helicon plasma device. Ion velocities and temperatures are derived from the measured Doppler broadened velocity distribution functions of argon ions. The LIF system employs a portable, high power (>300 mW), narrowband ({approx}1 MHz) tunable diode laser-based system operating at 668.614 nm. Previous studies in CSDX have shown the existence of a radially sheared azimuthal flow as measured with time delay estimation methods and Mach probes. Here, we report the first LIF measurements of sheared plasmamore » fluid flow in CSDX. Above a critical magnetic field, the ion fluid flow profile evolves from radially uniform to peaked on axis with a distinct reversed flow region at the boundary, indicating the development of a sheared azimuthal flow. Simultaneously, the ion temperature also evolves from a radially uniform profile to a profile with a gradient. Measurements in turbulent and coherent drift wave mode dominated plasmas are compared.« less

An implantable blood pressure and flow transmitter.

NASA Technical Reports Server (NTRS)

Rader, R. D.; Meehan, J. P.; Henriksen, J. K. C.

1973-01-01

A miniature totally implantable FM/FM telemetry system has been developed to simultaneously measure blood pressure and blood flow, thus providing an appreciation of the hemodynamics of the circulation to the entire body or to a particular organ. Developed for work with animal subjects, the telemetry system's transmission time is controlled by an RF signal that permits an operating life of several months. Pressure is detected by a miniature intravascular transducer and flow is detected by an extravascular interferometric ultrasonic technique. Both pressure and flow are calibrated prior to implanting. The pressure calibration can be checked after the implanting by cannulation; flow calibration can be verified only at the end of the experiment by determining the voltage output from the implanted sensing system as a function of several measured flow rates. The utility of this device has been established by its use in investigating canine renal circulation during exercise, emotional encounters, administration of drugs, and application of accelerative forces.

The Feasibility of Performing Particle Tracking Based Flow Measurements with Acoustic Cameras

DTIC Science & Technology

2017-08-01

particles that cannot be assumed to follow the fluid motion) affected by grid-generated turbulent flow in a wind tunnel to compare the particle...over other flow measurements systems, such as hot- wire anemometry, laser Doppler velocimetry, or acoustic Doppler velocimetry, is that PIV produces...Velocimetry Measurements of the Flow around a Rushton Turbine .” Experiments in Fluids 29(5): 478–485. doi:10.1007/s003480000116. Hjemfelt, A. T., and L. F

Effect of Very-High-Flow Nasal Therapy on Airway Pressure and End-Expiratory Lung Impedance in Healthy Volunteers.

PubMed

Parke, Rachael L; Bloch, Andreas; McGuinness, Shay P

2015-10-01

Previous research has demonstrated a positive linear correlation between flow delivered and airway pressure generated by high-flow nasal therapy. Current practice is to use flows over a range of 30-60 L/min; however, it is technically possible to apply higher flows. In this study, airway pressure measurements and electrical impedance tomography were used to assess the relationship between flows of up to 100 L/min and changes in lung physiology. Fifteen healthy volunteers were enrolled into this study. A high-flow nasal system capable of delivering a flow of 100 L/min was purpose-built using 2 Optiflow systems. Airway pressure was measured via the nasopharynx, and cumulative changes in end-expiratory lung impedance were recorded using the PulmoVista 500 system at gas flows of 30-100 L/min in increments of 10 L/min. The mean age of study participants was 31 (range 22-44) y, the mean ± SD height was 171.8 ± 7.5 cm, the mean ± SD weight was 69.7 ± 10 kg, and 47% were males. Flows ranged from 30 to 100 L/min with resulting mean ± SD airway pressures of 2.7 ± 0.7 to 11.9 ± 2.7 cm H2O. A cumulative and linear increase in end-expiratory lung impedance was observed with increasing flows, as well as a decrease in breathing frequency. Measured airway pressure and lung impedance increased linearly with increased gas flow. Observed airway pressures were in the range used clinically with face-mask noninvasive ventilation. Developments in delivery systems may result in this therapy being an acceptable alternative to face-mask noninvasive ventilation. Copyright © 2015 by Daedalus Enterprises.

Aerodynamic and Acoustic Tests of a 1/15 Scale Model Dry Cooled Jet Aircraft Runup Noise Suppression System,

DTIC Science & Technology

1975-10-01

sophisticated wet-cooled systems having scrubbers and their associated water treatment facilities . The United States Navy has recognized these Hush... venturi meter air inlet to measure the pumped air flow and the exhaust enclosure is provided with suitable ports for the flow to exit. The test program...constantan thermo- couple and venturi flow meters were used to measure the aerodynamic/thermo- dynamic information required from the tests (pressure

Nonintrusive Flow Rate Determination Through Space Shuttle Water Coolant Loop Floodlight Coldplate

NASA Technical Reports Server (NTRS)

Werlink, Rudolph; Johnson, Harry; Margasahayam, Ravi

1997-01-01

Using a Nonintrusive Flow Measurement System (NFMS), the flow rates through the Space Shuttle water coolant coldplate were determined. The objective of this in situ flow measurement was to prove or disprove a potential block inside the affected coldplate had contributed to a reduced flow rate and the subsequent ice formation on the Space Shuttle Discovery. Flow through the coldplate was originally calculated to be 35 to 38 pounds per hour. This application of ultrasonic technology advanced the envelope of flow measurements through use of 1/4-inch-diameter tubing, which resulted in extremely low flow velocities (5 to 30 pounds per hour). In situ measurements on the orbiters Discovery and Atlantis indicated both vehicles, on the average, experienced similar flow rates through the coldplate (around 25 pounds per hour), but lower rates than the designed flow. Based on the noninvasive checks, further invasive troubleshooting was eliminated. Permanent monitoring using the NFMS was recommended.

Aerodynamic Flow Field Measurements for Automotive Systems

NASA Technical Reports Server (NTRS)

Hepner, Timothy E.

1999-01-01

The design of a modern automotive air handling system is a complex task. The system is required to bring the interior of the vehicle to a comfortable level in as short a time as possible. A goal of the automotive industry is to predict the interior climate of an automobile using advanced computational fluid dynamic (CFD) methods. The development of these advanced prediction tools will enable better selection of engine and accessory components. The goal of this investigation was to predict methods used by the automotive industry. To accomplish this task three separate experiments were performed. The first was a laboratory setup where laser velocimeter (LV) flow field measurements were made in the heating and air conditioning unit of a Ford Windstar. The second involved flow field measurements in the engine compartment of a Ford Explorer, with the engine running idle. The third mapped the flow field exiting the center dashboard panel vent inside the Explorer, while the circulating fan operated at 14 volts. All three experiments utilized full-coincidence three-component LV systems. This enabled the mean and fluctuating velocities to be measured along with the Reynolds stress terms.

Seed Cotton Mass Flow Measurement in the Gin

USDA-ARS?s Scientific Manuscript database

Seed cotton mass flow measurement is necessary for the development of improved gin process control systems that can increase gin efficiency and improve fiber quality. Previous studies led to the development of a seed cotton mass flow rate sensor based on the static pressure drop across the blowbox, ...

Particle-sampling statistics in laser anemometers Sample-and-hold systems and saturable systems

NASA Technical Reports Server (NTRS)

Edwards, R. V.; Jensen, A. S.

1983-01-01

The effect of the data-processing system on the particle statistics obtained with laser anemometry of flows containing suspended particles is examined. Attention is given to the sample and hold processor, a pseudo-analog device which retains the last measurement until a new measurement is made, followed by time-averaging of the data. The second system considered features a dead time, i.e., a saturable system with a significant reset time with storage in a data buffer. It is noted that the saturable system operates independent of the particle arrival rate. The probabilities of a particle arrival in a given time period are calculated for both processing systems. It is shown that the system outputs are dependent on the mean particle flow rate, the flow correlation time, and the flow statistics, indicating that the particle density affects both systems. The results are significant for instances of good correlation between the particle density and velocity, such as occurs near the edge of a jet.

Determination of local values of gas and liquid mass flux in highly loaded two-phase flow

NASA Technical Reports Server (NTRS)

Burick, R. J.; Scheuerman, C. H.; Falk, A. Y.

1974-01-01

A measurement system using a deceleration probe was designed for determining the local values of gas and liquid mass flux in various gas/liquid droplet sprayfields. The system was used to characterize two-phase flowfields generated by gas/liquid rocket-motor injectors. Measurements were made at static pressures up to 500 psia and injected mass flow ratios up to 20. The measurement system can also be used at higher pressures and in gas/solid flowfields.

A fiber optic probe coupled low-cost CMOS-camera-based system for simultaneous measurement of oxy-, deoxyhemoglobin, and blood flow

NASA Astrophysics Data System (ADS)

Seong, Myeongsu; Phillips, Zephaniah; Mai, Phuong M.; Yeo, Chaebeom; Song, Cheol; Lee, Kijoon; Kim, Jae G.

2015-07-01

Appropriate oxygen supply and blood flow are important in coordination of body functions and maintaining a life. To measure both oxygen supply and blood flow simultaneously, we developed a system that combined near-infrared spectroscopy (NIRS) and diffuse speckle contrast analysis (DSCA). Our system is more cost effective and compact than such combined systems as diffuse correlation spectroscopy(DCS)-NIRS or DCS flow oximeter, and also offers the same quantitative information. In this article, we present the configuration of DSCA-NIRS and preliminary data from an arm cuff occlusion and a repeated gripping exercise. With further investigation, we believe that DSCA-NIRS can be a useful tool for the field of neuroscience, muscle physiology and metabolic diseases such as diabetes.

Numerical Technique for Analyzing Rotating Rake Mode Measurements in a Duct With Passive Treatment and Shear Flow

NASA Technical Reports Server (NTRS)

Dahl, Milo D.; Sutliff, Daniel L.

2007-01-01

A technique is presented for the analysis of measured data obtained from a rotating microphone rake system. The system is designed to measure the interaction modes of ducted fans. A Fourier analysis of the data from the rotating system results in a set of circumferential mode levels at each radial location of a microphone inside the duct. Radial basis functions are then least-squares fit to this data to obtain the radial mode amplitudes. For ducts with soft walls and mean flow, the radial basis functions must be numerically computed. The linear companion matrix method is used to obtain both the eigenvalues of interest, without an initial guess, and the radial basis functions. The governing equations allow for the mean flow to have a boundary layer at the wall. In addition, a nonlinear least-squares method is used to adjust the wall impedance to best fit the data in an attempt to use the rotating system as an in-duct wall impedance measurement tool. Simulated and measured data are used to show the effects of wall impedance and mean flow on the computed results.

An electronic flow control system for a variable-rate tree sprayer

USDA-ARS?s Scientific Manuscript database

Precise modulation of nozzle flow rates is a critical measure to achieve variable-rate spray applications. An electronic flow rate control system accommodating with microprocessors and pulse width modulation (PWM) controlled solenoid valves was designed to manipulate the output of spray nozzles inde...

Design and setup of intermittent-flow respirometry system for aquatic organisms.

PubMed

Svendsen, M B S; Bushnell, P G; Steffensen, J F

2016-01-01

Intermittent-flow respirometry is an experimental protocol for measuring oxygen consumption in aquatic organisms that utilizes the best features of closed (stop-flow) and flow-through respirometry while eliminating (or at least reducing) some of their inherent problems. By interspersing short periods of closed-chamber oxygen consumption measurements with regular flush periods, accurate oxygen uptake rate measurements can be made without the accumulation of waste products, particularly carbon dioxide, which may confound results. Automating the procedure with easily available hardware and software further reduces error by allowing many measurements to be made over long periods thereby minimizing animal stress due to acclimation issues. This paper describes some of the fundamental principles that need to be considered when designing and carrying out automated intermittent-flow respirometry (e.g. chamber size, flush rate, flush time, chamber mixing, measurement periods and temperature control). Finally, recent advances in oxygen probe technology and open source automation software will be discussed in the context of assembling relatively low cost and reliable measurement systems. © 2015 The Fisheries Society of the British Isles.

Automated structure and flow measurement - a promising tool in nailfold capillaroscopy.

PubMed

Berks, Michael; Dinsdale, Graham; Murray, Andrea; Moore, Tonia; Manning, Joanne; Taylor, Chris; Herrick, Ariane L

2018-07-01

Despite increasing interest in nailfold capillaroscopy, objective measures of capillary structure and blood flow have been little studied. We aimed to test the hypothesis that structural measurements, capillary flow, and a combined measure have the predictive power to separate patients with systemic sclerosis (SSc) from those with primary Raynaud's phenomenon (PRP) and healthy controls (HC). 50 patients with SSc, 12 with PRP, and 50 HC were imaged using a novel capillaroscopy system that generates high-quality nailfold images and provides fully-automated measurements of capillary structure and blood flow (capillary density, mean width, maximum width, shape score, derangement and mean flow velocity). Population statistics summarise the differences between the three groups. Areas under ROC curves (A Z ) were used to measure classification accuracy when assigning individuals to SSc and HC/PRP groups. Statistically significant differences in group means were found between patients with SSc and both HC and patients with PRP, for all measurements, e.g. mean width (μm) ± SE: 15.0 ± 0.71, 12.7 ± 0.74 and 11.8 ± 0.23 for SSc, PRP and HC respectively. Combining the five structural measurements gave better classification (A Z  = 0.919 ± 0.026) than the best single measurement (mean width, A Z  = 0.874 ± 0.043), whilst adding flow further improved classification (A Z  = 0.930 ± 0.024). Structural and blood flow measurements are both able to distinguish patients with SSc from those with PRP/HC. Importantly, these hold promise as clinical trial outcome measures for treatments aimed at improving finger blood flow or microvascular remodelling. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Bluetooth-based distributed measurement system

NASA Astrophysics Data System (ADS)

Tang, Baoping; Chen, Zhuo; Wei, Yuguo; Qin, Xiaofeng

2007-07-01

A novel distributed wireless measurement system, which is consisted of a base station, wireless intelligent sensors and relay nodes etc, is established by combining of Bluetooth-based wireless transmission, virtual instrument, intelligent sensor, and network. The intelligent sensors mounted on the equipments to be measured acquire various parameters and the Bluetooth relay nodes get the acquired data modulated and sent to the base station, where data analysis and processing are done so that the operational condition of the equipment can be evaluated. The establishment of the distributed measurement system is discussed with a measurement flow chart for the distributed measurement system based on Bluetooth technology, and the advantages and disadvantages of the system are analyzed at the end of the paper and the measurement system has successfully been used in Daqing oilfield, China for measurement of parameters, such as temperature, flow rate and oil pressure at an electromotor-pump unit.

Energy measurement using flow computers and chromatography

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

Beeson, J.

1995-12-01

Arkla Pipeline Group (APG), along with most transmission companies, went to electronic flow measurement (EFM) to: (1) Increase resolution and accuracy; (2) Real time correction of flow variables; (3) Increase speed in data retrieval; (4) Reduce capital expenditures; and (5) Reduce operation and maintenance expenditures Prior to EFM, mechanical seven day charts were used which yielded 800 pressure and differential pressure readings. EFM yields 1.2-million readings, a 1500 time improvement in resolution and additional flow representation. The total system accuracy of the EFM system is 0.25 % compared with 2 % for the chart system which gives APG improved accuracy.more » A typical APG electronic measurement system includes a microprocessor-based flow computer, a telemetry communications package, and a gas chromatograph. Live relative density (specific gravity), BTU, CO{sub 2}, and N{sub 2} are updated from the chromatograph to the flow computer every six minutes which provides accurate MMBTU computations. Because the gas contract length has changed from years to monthly and from a majority of direct sales to transports both Arkla and its customers wanted access to actual volumes on a much more timely basis than is allowed with charts. The new electronic system allows volumes and other system data to be retrieved continuously, if EFM is on Supervisory Control and Data Acquisition (SCADA) or daily if on dial up telephone. Previously because of chart integration, information was not available for four to six weeks. EFM costs much less than the combined costs of telemetry transmitters, pressure and differential pressure chart recorders, and temperature chart recorder which it replaces. APG will install this equipment on smaller volume stations at a customers expense. APG requires backup measurement on metering facilities this size. It could be another APG flow computer or chart recorder, or the other companies flow computer or chart recorder.« less

Ultrasonic flow measurements for irrigation process monitoring

NASA Astrophysics Data System (ADS)

Ziani, Elmostafa; Bennouna, Mustapha; Boissier, Raymond

2004-02-01

This paper presents the state of the art of the general principle of liquid flow measurements by ultrasonic method, and problems of flow measurements. We present an ultrasonic flowmeter designed according to smart sensors concept, for the measurement of irrigation water flowing through pipelines or open channels, using the ultrasonic transit time approach. The new flowmeter works on the principle of measuring time delay differences between sound pulses transmitted upstream and downstream in the flowing liquid. The speed of sound in the flowing medium is eliminated as a variable because the flowrate calculations are based on the reciprocals of the transmission times. The transit time difference is digitally measured by means of a suitable, microprocessor controlled logic. This type of ultrasonic flowmeter will be widely used in industry and water management, it is well studied in this work, followed by some experimental results. For pressurized channels, we use one pair of ultrasonic transducer arranged in proper positions and directions of the pipe, in this case, to determine the liquid velocity, a real time on-line analysis taking account the geometries of the hydraulic system, is applied to the obtained ultrasonic data. In the open channels, we use a single or two pairs of ultrasonic emitter-receiver according to the desired performances. Finally, the goals of this work consist in integrating the smart sensor into irrigation systems monitoring in order to evaluate potential advantages and demonstrate their performance, on the other hand, to understand and use ultrasonic approach for determining flow characteristics and improving flow measurements by reducing errors caused by disturbances of the flow profiles.

Large Field of View PIV Measurements of Air Entrainment by SLS SMAT Water Sound Suppression System

NASA Astrophysics Data System (ADS)

Stegmeir, Matthew; Pothos, Stamatios; Bissell, Dan

2015-11-01

Water-based sound suppressions systems have been used to reduce the acoustic impact of space vehicle launches. Water flows at a high rate during launch in order to suppress Engine Generated Acoustics and other potentially damaging sources of noise. For the Space Shuttle, peak flow rates exceeded 900,000 gallons per minute. Such large water flow rates have the potential to induce substantial entrainment of the surrounding air, affecting the launch conditions and generating airflow around the launch vehicle. Validation testing is necessary to quantify this impact for future space launch systems. In this study, PIV measurements were performed to map the flow field above the SMAT sub-scale launch vehicle scaled launch stand. Air entrainment effects generated by a water-based sound suppression system were studied. Mean and fluctuating fluid velocities were mapped up to 1m above the test stand deck and compared to simulation results. Measurements performed with NASA MSFC.

Velocimetry using scintillation of a laser beam for a laser-based gas-flux monitor

NASA Astrophysics Data System (ADS)

Kagawa, Naoki; Wada, Osami; Koga, Ryuji

1999-05-01

This paper describes a velocimetry system using scintillation of a laser-beam with spatial filters based on sensor arrays for a laser- based gas flux monitor. In the eddy correlation method, gas flux is obtained by mutual relation between the gas density and the flow velocity. The velocimetry system is developed to support the flow velocity monitor portion of the laser-based gas flux monitor with a long span for measurement. In order to sense not only the flow velocity but also the flow direction, two photo diode arrays are arranged with difference of a quarter period of the weighting function between them; the two output signals from the sensor arrays have phase difference of either (pi) /2 or -(pi) /2 depending on the sense of flow direction. In order to obtain the flow velocity and the flow direction instantly, an electronic apparatus built by the authors extracts frequency and phase from crude outputs of the pair of sensors. A feasibility of the velocimetry was confirmed indoors by measurement of the flow- velocity vector of the convection. Measured flow-velocity vector of the upward flow agreed comparatively with results of an ultrasonic anemometer.

40 CFR 63.605 - Monitoring requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the mass flow of phosphorus-bearing feed material to the process. The monitoring system shall have an... either the mass flow of phosphorus-bearing feed material to the dryer or calciner, or the mass flow of... total mass rate in metric ton/hour of phosphorus bearing feed using a monitoring system for measuring...

40 CFR 63.605 - Monitoring requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the mass flow of phosphorus-bearing feed material to the process. The monitoring system shall have an... either the mass flow of phosphorus-bearing feed material to the dryer or calciner, or the mass flow of... total mass rate in metric ton/hour of phosphorus bearing feed using a monitoring system for measuring...

Measurement and control systems for an imaging electromagnetic flow metre.

PubMed

Zhao, Y Y; Lucas, G; Leeungculsatien, T

2014-03-01

Electromagnetic flow metres based on the principles of Faraday's laws of induction have been used successfully in many industries. The conventional electromagnetic flow metre can measure the mean liquid velocity in axisymmetric single phase flows. However, in order to achieve velocity profile measurements in single phase flows with non-uniform velocity profiles, a novel imaging electromagnetic flow metre (IEF) has been developed which is described in this paper. The novel electromagnetic flow metre which is based on the 'weight value' theory to reconstruct velocity profiles is interfaced with a 'Microrobotics VM1' microcontroller as a stand-alone unit. The work undertaken in the paper demonstrates that an imaging electromagnetic flow metre for liquid velocity profile measurement is an instrument that is highly suited for control via a microcontroller. © 2013 ISA Published by ISA All rights reserved.

Experimental study of porous media flow using hydro-gel beads and LED based PIV

NASA Astrophysics Data System (ADS)

Harshani, H. M. D.; Galindo-Torres, S. A.; Scheuermann, A.; Muhlhaus, H. B.

2017-01-01

A novel experimental approach for measuring porous flow characteristics using spherical hydro-gel beads and particle image velocimetry (PIV) technique is presented. A transparent porous medium consisting of hydro-gel beads that are made of a super-absorbent polymer, allows using water as the fluid phase while simultaneously having the same refractive index. As a result, a more adaptable and cost effective refractive index matched (RIM) medium is created. The transparent nature of the porous medium allows optical systems to visualize the flow field by using poly-amide seeding particles (PSP). Low risk light emitting diode (LED) based light was used to illuminate the plane in order to track the seeding particles’ path for the characterization of the flow inside the porous medium. The system was calibrated using a manually measured flow by a flow meter. Velocity profiles were obtained and analysed qualitatively and quantitatively in order to characterise the flow. Results show that this adaptable, low risk experimental set-up can be used for flow measurements in porous medium under low Reynolds numbers. The limitations of using hydro-gel beads are also discussed.

Measurement of Air Flow Characteristics Using Seven-Hole Cone Probes

NASA Technical Reports Server (NTRS)

Takahashi, Timothy T.

1997-01-01

The motivation for this work has been the development of a wake survey system. A seven-hole probe can measure the distribution of static pressure, total pressure, and flow angularity in a wind tunnel environment. The author describes the development of a simple, very efficient algorithm to compute flow properties from probe tip pressures. Its accuracy and applicability to unsteady, turbulent flow are discussed.

High-flow oxygen therapy: pressure analysis in a pediatric airway model.

PubMed

Urbano, Javier; del Castillo, Jimena; López-Herce, Jesús; Gallardo, José A; Solana, María J; Carrillo, Ángel

2012-05-01

The mechanism of high-flow oxygen therapy and the pressures reached in the airway have not been defined. We hypothesized that the flow would generate a low continuous positive pressure, and that elevated flow rates in this model could produce moderate pressures. The objective of this study was to analyze the pressure generated by a high-flow oxygen therapy system in an experimental model of the pediatric airway. An experimental in vitro study was performed. A high-flow oxygen therapy system was connected to 3 types of interface (nasal cannulae, nasal mask, and oronasal mask) and applied to 2 types of pediatric manikin (infant and neonatal). The pressures generated in the circuit, in the airway, and in the pharynx were measured at different flow rates (5, 10, 15, and 20 L/min). The experiment was conducted with and without a leak (mouth sealed and unsealed). Linear regression analyses were performed for each set of measurements. The pressures generated with the different interfaces were very similar. The maximum pressure recorded was 4 cm H(2)O with a flow of 20 L/min via nasal cannulae or nasal mask. When the mouth of the manikin was held open, the pressures reached in the airway and pharynxes were undetectable. Linear regression analyses showed a similar linear relationship between flow and pressures measured in the pharynx (pressure = -0.375 + 0.138 × flow) and in the airway (pressure = -0.375 + 0.158 × flow) with the closed mouth condition. According to our hypothesis, high-flow oxygen therapy systems produced a low-level CPAP in an experimental pediatric model, even with the use of very high flow rates. Linear regression analyses showed similar linear relationships between flow and pressures measured in the pharynx and in the airway. This finding suggests that, at least in part, the effects may be due to other mechanisms.

Model calibration and issues related to validation, sensitivity analysis, post-audit, uncertainty evaluation and assessment of prediction data needs

USGS Publications Warehouse

Tiedeman, Claire; Hill, Mary C.

2007-01-01

When simulating natural and engineered groundwater flow and transport systems, one objective is to produce a model that accurately represents important aspects of the true system. However, using direct measurements of system characteristics, such as hydraulic conductivity, to construct a model often produces simulated values that poorly match observations of the system state, such as hydraulic heads, flows and concentrations (for example, Barth et al., 2001). This occurs because of inaccuracies in the direct measurements and because the measurements commonly characterize system properties at different scales from that of the model aspect to which they are applied. In these circumstances, the conservation of mass equations represented by flow and transport models can be used to test the applicability of the direct measurements, such as by comparing model simulated values to the system state observations. This comparison leads to calibrating the model, by adjusting the model construction and the system properties as represented by model parameter values, so that the model produces simulated values that reasonably match the observations.

Optimal Sensor Layouts in Underwater Locomotory Systems

NASA Astrophysics Data System (ADS)

Colvert, Brendan; Kanso, Eva

2015-11-01

Retrieving and understanding global flow characteristics from local sensory measurements is a challenging but extremely relevant problem in fields such as defense, robotics, and biomimetics. It is an inverse problem in that the goal is to translate local information into global flow properties. In this talk we present techniques for optimization of sensory layouts within the context of an idealized underwater locomotory system. Using techniques from fluid mechanics and control theory, we show that, under certain conditions, local measurements can inform the submerged body about its orientation relative to the ambient flow, and allow it to recognize local properties of shear flows. We conclude by commenting on the relevance of these findings to underwater navigation in engineered systems and live organisms.

Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

NASA Astrophysics Data System (ADS)

Werkmeister, René M.; Vietauer, Martin; Knopf, Corinna; Fürnsinn, Clemens; Leitgeb, Rainer A.; Reitsamer, Herbert; Gröschl, Martin; Garhöfer, Gerhard; Vilser, Walthard; Schmetterer, Leopold

2014-10-01

A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique. The system was operated with an 841-nm superluminescent diode and a charge-coupled device camera that could be operated at a line rate of 20 kHz. We show that the system is capable of quantifying the response of 100% oxygen breathing on the retinal blood flow. In six rats, we observed a decrease in retinal vessel diameters of 13.2% and a decrease in retinal blood velocity of 42.6%, leading to a decrease in retinal blood flow of 56.7%. Furthermore, in four rats, the response of retinal blood flow during stimulation with diffuse flicker light was assessed. Retinal vessel diameter and blood velocity increased by 3.4% and 28.1%, respectively, leading to a relative increase in blood flow of 36.2%;. The presented technique shows much promise to quantify early changes in retinal blood flow during provocation with various stimuli in rodent models of ocular diseases in rats.

Non-Intrusive Pressure/Multipurpose Sensor and Method

NASA Technical Reports Server (NTRS)

Smith, William C. (Inventor)

2001-01-01

Method and apparatus are provided for determining pressure using a non-intrusive sensor that is easily attachable to the plumbing of a pressurized system. A bent mode implementation and a hoop mode implementation of the invention are disclosed. Each of these implementations is able to nonintrusively measure pressure while fluid is flowing. As well, each implementation may be used to measure mass flow rate simultaneously with pressure. An ultra low noise control system is provided for making pressure measurements during gas flow. The control system includes two tunable digital bandpass filters with center frequencies that are responsive to a clock frequency. The clock frequency is divided by a factor of N to produce a driving vibrational signal for resonating a metal sensor section.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

PubMed

Donaldsson, Snorri; Falk, Markus; Jonsson, Baldvin; Drevhammar, Thomas

2015-01-01

The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing

PubMed Central

2015-01-01

Background The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Methods Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. Results The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. Conclusion The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates. PMID:26192188

Static test-stand performance of the YF-102 turbofan engine with several exhaust configurations for the Quiet Short-Haul Research Aircraft (QSRA)

NASA Technical Reports Server (NTRS)

Mcardle, J. G.; Homyak, L.; Moore, A. S.

1979-01-01

The performance of a YF-102 turbofan engine was measured in an outdoor test stand with a bellmouth inlet and seven exhaust-system configurations. The configurations consisted of three separate-flow systems of various fan and core nozzle sizes and four confluent-flow systems of various nozzle sizes and shapes. A computer program provided good estimates of the engine performance and of thrust at maximum rating for each exhaust configuration. The internal performance of two different-shaped core nozzles for confluent-flow configurations was determined to be satisfactory. Pressure and temperature surveys were made with a traversing probe in the exhaust-nozzle flow for some confluent-flow configurations. The survey data at the mixing plane, plus the measured flow rates, were used to calculate the static-pressure variation along the exhaust nozzle length. The computed pressures compared well with experimental wall static-pressure data. External-flow surveys were made, for some confluent-flow configurations, with a large fixed rake at various locations in the exhaust plume.

An investigation of two phase flow pressure drops in a reduced acceleration environment

NASA Astrophysics Data System (ADS)

Wheeler, Montgomery W.; Best, Frederick R.; Reinarts, Thomas R.

1993-01-01

Thermal systems for space applications based on two phase flow have several advantages over single phase systems. Two phase thermal energy management and dynamic power conversion system advantages include the capability of achieving high specific power levels. Before two phase systems for space applications can be designed effectively, knowledge of the flow behavior in a reduced acceleration environment is necessary. To meet these needs, two phase flow experiments were conducted aboard the National Aeronautic and Space Administration's KC-135 using R12 as the working fluid. Annular flow two phase pressure drops were measured through 10.41-mm ID 1.251-m long glass tubing during periods with acceleration levels in the range ±0.05 G. The experiments were conducted with emphasis on achieving data with a high level of accuracy. The reduced acceleration annular flow pressure drops were compred with pressure drops measured in a 1-G environment for similar flow conditions. The reduced acceleration pressure drops were found to be 45% greater than the 1-G pressure drops. In addition, the reduced acceleration annular flow interfacial friction factors were compared with models for vertical up-flow in a 1-G environment. The reduced acceleration interfacial friction factor data was not predicted by the 1-G models.

Quantity and quality of ground-water discharge to the South Platte River, Denver to Fort Lupton, Colorado, August 1992 through July 1993

USGS Publications Warehouse

McMahon, P.B.; Lull, K.J.; Dennehy, K.F.; Collins, J.A.

1995-01-01

Water-quality studies conducted by the Metro Wastewater Reclamation District have indicated that during low flow in segments of the South Platte River between Denver and Fort Lupton, concentrations of dissolved oxygen are less than minimum concen- trations set by the State of Colorado. Low dissolved-oxygen concentrations are observed in two reaches of the river-they are about 3.3 to 6.4 miles and 17 to 25 miles downstream from the Metro Waste- water Reclamation District effluent outfalls. Concentrations of dissolved oxygen recover between these two reaches. Studies conducted by the U.S. Geological Survey have indicated that ground-water discharge to the river may contribute to these low dissolved-oxygen concentrations. As a result, an assessment was made of the quantity and quality of ground-water discharge to the South Platte River from Denver to Fort Lupton. Measurements of surface- water and ground-water discharge and collections of surface water and ground water for water-quality analyses were made from August 1992 through January 1993 and in May and July 1993. The quantity of ground-water discharge to the South Platte River was determined indirectly by mass balance of surface-water inflows and outflows and directly by instantaneous measurements of ground-water discharge across the sediment/water interface in the river channel. The quality of surface water and ground water was determined by sampling and analysis of water from the river and monitoring wells screened in the alluvial aquifer adjacent to the river and by sampling and analysis of water from piezometers screened in sediments underlying the river channel. The ground-water flow system was subdivided into a large-area and a small-area flow system. The precise boundaries of the two flow systems are not known. However, the large-area flow system is considered to incorporate all alluvial sediments in hydrologic connection with the South Platte River. The small- area flow system is considered to incorporate the alluvial aquifer in the vicinity of the river. Flow-path lengths in the large-area flow system were considered to be on the order of hundreds of feet to more than a mile, whereas in the small-area flow system, they were considered to be on the order of feet to hundreds of feet. Mass-balance estimates of incremental ground-water discharge from the large- area flow system ranged from -27 to 17 cubic feet per second per mile in three reaches of the river; the median rate was 4.6 cubic feet per second per mile. The median percentage of surface-water discharge derived from ground-water discharge in the river reaches studied was 13 percent. Instantaneous measurements of ground-water discharge from the small-area flow system ranged from -1,360 to 1,000 cubic feet per second per mile, with a median value of -5.8 cubic feet per second per mile. Hourly measurements of discharge from the small-area flow system indicated that the high rates of discharge were transient and may have been caused by daily fluctuations in river stage due to changing effluent-discharge rates from the Metro Wastewater Reclamation District treatment plant. Higher river stages caused surface water to infiltrate bed sediments underlying the river channel, and lower river stages allowed ground water to discharge into the river. Although stage changes apparently cycled large quantities of water in and out of the small- area flow system, the process probably provided no net gain or loss of water to the river. In general, mass balance and instantaneous measurements of ground-water discharge indicated that the ground- water flow system in the vicinity of the river consisted of a large-area flow system that provided a net addition of water to the river and a small- area flow system that cycled water in and out of the riverbed sediments, but provided no net addition of water to the river. The small-area flow system was superimposed on the large-area flow system. The median values of pH and dissolved oxygen

Wind field measurement in the nonprecipitous regions surrounding storms by an airborne pulsed Doppler lidar system, appendix A

NASA Technical Reports Server (NTRS)

Bilbro, J. W.; Vaughan, W. W.

1980-01-01

Coherent Doppler lidar appears to hold great promise in contributing to the basic store of knowledge concerning flow field characteristics in the nonprecipitous regions surrounding severe storms. The Doppler lidar, through its ability to measure clear air returns, augments the conventional Doppler radar system, which is most useful in the precipitous regions of the storm. A brief description of the Doppler lidar severe storm measurement system is provided along with the technique to be used in performing the flow field measurements. The application of the lidar is addressed, and the planned measurement program is outlined.

Vision-based system for the control and measurement of wastewater flow rate in sewer systems.

PubMed

Nguyen, L S; Schaeli, B; Sage, D; Kayal, S; Jeanbourquin, D; Barry, D A; Rossi, L

2009-01-01

Combined sewer overflows and stormwater discharges represent an important source of contamination to the environment. However, the harsh environment inside sewers and particular hydraulic conditions during rain events reduce the reliability of traditional flow measurement probes. In the following, we present and evaluate an in situ system for the monitoring of water flow in sewers based on video images. This paper focuses on the measurement of the water level based on image-processing techniques. The developed image-based water level algorithms identify the wall/water interface from sewer images and measure its position with respect to real world coordinates. A web-based user interface and a 3-tier system architecture enable the remote configuration of the cameras and the image-processing algorithms. Images acquired and processed by our system were found to reliably measure water levels and thereby to provide crucial information leading to better understand particular hydraulic behaviors. In terms of robustness and accuracy, the water level algorithm provided equal or better results compared to traditional water level probes in three different in situ configurations.

Velocimetry with refractive index matching for complex flow configurations, phase 1

NASA Technical Reports Server (NTRS)

Thompson, B. E.; Vafidis, C.; Whitelaw, J. H.

1987-01-01

The feasibility of obtaining detailed velocity field measurements in large Reynolds number flow of the Space Shuttle Main Engine (SSME) main injector bowl was demonstrated using laser velocimetry and the developed refractive-index-matching technique. An experimental system to provide appropriate flow rates and temperature control of refractive-index-matching fluid was designed and tested. Test results are presented to establish the feasibility of obtaining accurate velocity measurements that map the entire field including the flow through the LOX post bundles: sample mean velocity, turbulence intensity, and spectral results are presented. The results indicate that a suitable fluid and control system is feasible for the representation of complex rocket-engine configurations and that measurements of velocity characteristics can be obtained without the optical access restrictions normally associated with laser velocimetry. The refractive-index-matching technique considered needs to be further developed and extended to represent other rocket-engine flows where current methods either cannot measure with adequate accuracy or they fail.

Nitric Oxide PLIF Measurements in the Hypersonic Materials Environmental Test System (HYMETS)

NASA Technical Reports Server (NTRS)

Inman, Jennifer A.; Bathel, Brett F.; Johansen, Craig T.; Danehy, Paul M.; Jones, Stephen B.; Gragg, Jeffrey G.; Splinter, Scott C.

2011-01-01

A nonintrusive laser-based measurement system has been applied for the first time in the HYMETS (Hypersonic Materials Environmental Test System) 400 kW arc-heated wind tunnel at NASA Langley Research Center. Planar laser-induced fluorescence of naturally occurring nitric oxide (NO) has been used to obtain instantaneous flow visualization images, and to make both radial and axial velocity measurements. Results are presented at selected facility run conditions, including some in simulated Earth atmosphere (75% nitrogen, 20% oxygen, 5% argon) and others in simulated Martian atmosphere (71% carbon dioxide, 24% nitrogen, 5% argon), for bulk enthalpies ranging from 6.5 MJ/kg to 18.4 MJ/kg. Flow visualization images reveal the presence of large scale unsteady flow structures, and indicate nitric oxide fluorescence signal over more than 70% of the core flow for bulk enthalpies below about 11 MJ/kg, but over less than 10% of the core flow for bulk enthalpies above about 16 MJ/kg. Axial velocimetry was performed using molecular tagging velocimetry (MTV). Axial velocities of about 3 km/s were measured along the centerline. Radial velocimetry was performed by scanning the wavelength of the narrowband laser and analyzing the resulting Doppler shift. Radial velocities of 0.5km/s were measured.

Sensitivity Analysis for Steady State Groundwater Flow Using Adjoint Operators

NASA Astrophysics Data System (ADS)

Sykes, J. F.; Wilson, J. L.; Andrews, R. W.

1985-03-01

Adjoint sensitivity theory is currently being considered as a potential method for calculating the sensitivity of nuclear waste repository performance measures to the parameters of the system. For groundwater flow systems, performance measures of interest include piezometric heads in the vicinity of a waste site, velocities or travel time in aquifers, and mass discharge to biosphere points. The parameters include recharge-discharge rates, prescribed boundary heads or fluxes, formation thicknesses, and hydraulic conductivities. The derivative of a performance measure with respect to the system parameters is usually taken as a measure of sensitivity. To calculate sensitivities, adjoint sensitivity equations are formulated from the equations describing the primary problem. The solution of the primary problem and the adjoint sensitivity problem enables the determination of all of the required derivatives and hence related sensitivity coefficients. In this study, adjoint sensitivity theory is developed for equations of two-dimensional steady state flow in a confined aquifer. Both the primary flow equation and the adjoint sensitivity equation are solved using the Galerkin finite element method. The developed computer code is used to investigate the regional flow parameters of the Leadville Formation of the Paradox Basin in Utah. The results illustrate the sensitivity of calculated local heads to the boundary conditions. Alternatively, local velocity related performance measures are more sensitive to hydraulic conductivities.

Validation of thermal techniques for measurement of pelvic organ blood flows in the nonpregnant sheep: comparison with transit-time ultrasonic and microsphere measurements of blood flow

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

Randall, N.J.; Beard, R.W.; Sutherland, I.A.

1988-03-01

Data obtained from a thermal system capable of measuring changes in organ temperature as well as tissue thermal clearance in the uterus and vagina have been compared with blood flow measured continuously with a transit-time ultrasound volume-flow sensor placed around the common internal iliac artery and intermittently with radioactive microspheres in the chronically instrumented nonpregnant sheep. Temperature changes in both the uterus and the vagina correlated well with blood flow changes measured by both techniques after intravenous administration of estradiol or norepinephrine. Thermal clearance did not correlate well with blood flow in the vagina or uterus. These methods may havemore » value in the investigation of blood flow patterns in various clinical situations such as the pelvic pain syndrome and early pregnancy.« less

Experimental Measurement of Small Scale Multirotor Flows

NASA Astrophysics Data System (ADS)

Connors, Jacob; Weiner, Joseph; Velarde, John-Michael; Glauser, Mark

2017-11-01

Work is being done to create a multirotor Unmanned Air Vehicle (UAV) based anemometer system that would allow for measurement of velocity and spectra in the atmospheric boundary layer. The flow from the UAV's rotors will impact such measurements and hence must be filtered. This study focuses on measuring the fluctuations of the velocity field in the flow both above and below various UAVs to determine first, the feasibility of the creation of the filter, and second, the optimal placement of the system on the body of the UAV. These measurements are taking place in both Syracuse University's subsonic wind tunnel and Skytop Turbulence Lab's Indoor Flow Lab. Constant Temperature Anemometry is being used to measure these velocity field fluctuations across a variety of UAVs with differing characteristics such as size, number of propellers, and rotor blade type. The data from these experiments is being used to define a method to estimate the filter band required to isolate noise from wake effects, and determine ideal sensor placement based on characteristics of the vehicle's design alone. The authors would like to thank The Center for Advanced Systems and Engineering (CASE) at Syracuse University for funding and supporting this work.

Rotating permanent magnet excitation for blood flow measurement.

PubMed

Nair, Sarath S; Vinodkumar, V; Sreedevi, V; Nagesh, D S

2015-11-01

A compact, portable and improved blood flow measurement system for an extracorporeal circuit having a rotating permanent magnetic excitation scheme is described in this paper. The system consists of a set of permanent magnets rotating near blood or any conductive fluid to create high-intensity alternating magnetic field in it and inducing a sinusoidal varying voltage across the column of fluid. The induced voltage signal is acquired, conditioned and processed to determine its flow rate. Performance analysis shows that a sensitivity of more than 250 mV/lpm can be obtained, which is more than five times higher than conventional flow measurement systems. Choice of rotating permanent magnet instead of an electromagnetic core generates alternate magnetic field of smooth sinusoidal nature which in turn reduces switching and interference noises. These results in reduction in complex electronic circuitry required for processing the signal to a great extent and enable the flow measuring device to be much less costlier, portable and light weight. The signal remains steady even with changes in environmental conditions and has an accuracy of greater than 95%. This paper also describes the construction details of the prototype, the factors affecting sensitivity and detailed performance analysis at various operating conditions.

Ionization based multi-directional flow sensor

DOEpatents

Chorpening, Benjamin T [Morgantown, WV; Casleton, Kent H [Morgantown, WV

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.

Particle Streak Anemometry: A New Method for Proximal Flow Sensing from Aircraft

NASA Astrophysics Data System (ADS)

Nichols, T. W.

Accurate sensing of relative air flow direction from fixed-wing small unmanned aircraft (sUAS) is challenging with existing multi-hole pitot-static and vane systems. Sub-degree direction accuracy is generally not available on such systems and disturbances to the local flow field, induced by the airframe, introduce an additional error source. An optical imaging approach to make a relative air velocity measurement with high-directional accuracy is presented. Optical methods offer the capability to make a proximal measurement in undisturbed air outside of the local flow field without the need to place sensors on vulnerable probes extended ahead of the aircraft. Current imaging flow analysis techniques for laboratory use rely on relatively thin imaged volumes and sophisticated hardware and intensity thresholding in low-background conditions. A new method is derived and assessed using a particle streak imaging technique that can be implemented with low-cost commercial cameras and illumination systems, and can function in imaged volumes of arbitrary depth with complex background signal. The new technique, referred to as particle streak anemometry (PSA) (to differentiate from particle streak velocimetry which makes a field measurement rather than a single bulk flow measurement) utilizes a modified Canny Edge detection algorithm with a connected component analysis and principle component analysis to detect streak ends in complex imaging conditions. A linear solution for the air velocity direction is then implemented with a random sample consensus (RANSAC) solution approach. A single DOF non-linear, non-convex optimization problem is then solved for the air speed through an iterative approach. The technique was tested through simulation and wind tunnel tests yielding angular accuracies under 0.2 degrees, superior to the performance of existing commercial systems. Air speed error standard deviations varied from 1.6 to 2.2 m/s depending on the techniques of implementation. While air speed sensing is secondary to accurate flow direction measurement, the air speed results were in line with commercial pitot static systems at low speeds.

Doppler global velocimetry: Development of a flight research instrumentation system for application to non-intrusive measurements of the flow field

NASA Technical Reports Server (NTRS)

Komine, Hiroshi; Brosnan, Stephen J.; Long, William H.; Stappaerts, Eddy A.

1994-01-01

Doppler Global Velocimetry (DGV) is a new diagnostic tool that offers potential for flow field measurements in flight by acquiring three-component velocity data in near real-time during flight maneuvers. The feasibility of implementation of a flight DGV system aboard NASA's High-Angle-of-Attack Research Vehicle (HARV) was addressed in this work by identifying the essential characteristics of a flight measurement system and by performing calibration and error tests. Results from this work were: an outline that establishes a preliminary basis for system configurations by analyzing measurement errors, installation issues, and operating requirements; measurement of the accuracy of the DGV technique using a laboratory breadboard DGV system based on a frequency-doubled Nd: YAG laser and iodine Absorption Line Filter (ALF), which showed excellent agreement between the DGV data and pilot measurements on a laminar flow jet with velocities of up to 150 m/sec; a survey of DGV system components and technologies that are relevant to the design of a flight measurement system, including a survey of cameras for the next generation DGV receivers; an assessment of the candidate lasers and absorption line filters for the flight system, resulting in a near-term recommendation of Nd: host lasers and an iodine ALF for both flight and wind tunnel applications.

Automated flow quantification in valvular heart disease based on backscattered Doppler power analysis: implementation on matrix-array ultrasound imaging systems.

PubMed

Buck, Thomas; Hwang, Shawn M; Plicht, Björn; Mucci, Ronald A; Hunold, Peter; Erbel, Raimund; Levine, Robert A

2008-06-01

Cardiac ultrasound imaging systems are limited in the noninvasive quantification of valvular regurgitation due to indirect measurements and inaccurate hemodynamic assumptions. We recently demonstrated that the principle of integration of backscattered acoustic Doppler power times velocity can be used for flow quantification in valvular regurgitation directly at the vena contracta of a regurgitant flow jet. We now aimed to accomplish implementation of automated Doppler power flow analysis software on a standard cardiac ultrasound system utilizing novel matrix-array transducer technology with detailed description of system requirements, components and software contributing to the system. This system based on a 3.5 MHz, matrix-array cardiac ultrasound scanner (Sonos 5500, Philips Medical Systems) was validated by means of comprehensive experimental signal generator trials, in vitro flow phantom trials and in vivo testing in 48 patients with mitral regurgitation of different severity and etiology using magnetic resonance imaging (MRI) for reference. All measurements displayed good correlation to the reference values, indicating successful implementation of automated Doppler power flow analysis on a matrix-array ultrasound imaging system. Systematic underestimation of effective regurgitant orifice areas >0.65 cm(2) and volumes >40 ml was found due to currently limited Doppler beam width that could be readily overcome by the use of new generation 2D matrix-array technology. Automated flow quantification in valvular heart disease based on backscattered Doppler power can be fully implemented on board a routinely used matrix-array ultrasound imaging systems. Such automated Doppler power flow analysis of valvular regurgitant flow directly, noninvasively, and user independent overcomes the practical limitations of current techniques.

Measurement of the Shear Lift Force on a Bubble in a Channel Flow

NASA Technical Reports Server (NTRS)

Nahra, Henry K.; Motil, Brian; Skor, Mark

2005-01-01

Two-phase flow systems play vital roles in the design of some current and anticipated space applications of two-phase systems which include: thermal management systems, transfer line flow in cryogenic storage, space nuclear power facilities, design and operation of thermal bus, life support systems, propulsion systems, In Situ Resource Utilization (ISRU), and space processes for pharmaceutical applications. The design of two-phase flow systems for space applications requires a clear knowledge of the behaviors of the dispersed phase (bubble), its interaction with the continuous phase (liquid) and its effect on heat and mass transfer processes, The need to understand the bubble generation process arises from the fact that for all space applications, the size and distribution of bubbles are extremely crucial for heat and mass transfer control. One important force in two-phase flow systems is the lift force on a bubble or particle in a liquid shear flow. The shear lift is usually overwhelmed by buoyancy in normal gravity, but it becomes an important force in reduced gravity. Since the liquid flow is usually sheared because of the confining wall, the trajectories of bubbles and particles injected into the liquid flow are affected by the shear lift in reduced gravity. A series of experiments are performed to investigate the lift force on a bubble in a liquid shear flow and its effect on the detachment of a bubble from a wall under low gravity conditions. Experiments are executed in a Poiseuille flow in a channel. An air-water system is used in these experiments that are performed in the 2.2 second drop tower. A bubble is injected into the shear flow from a small injector and the shear lift is measured while the bubble is held stationary relative to the fluid. The trajectory of the bubble prior, during and after its detachment from the injector is investigated. The measured shear lift force is calculated from the trajectory of the bubble at the detachment point. These values for the shear lift are then compared with the theoretical predictions from various published works on shear lift in the open literature, which include asymptotic solutions at low bubble Reynolds number, potential flow predictions and numerical studies that deal with intermediate bubble Reynolds numbers.

A technique for measuring hypersonic flow velocity profiles

NASA Technical Reports Server (NTRS)

Gartrell, L. R.

1973-01-01

A technique for measuring hypersonic flow velocity profiles is described. This technique utilizes an arc-discharge-electron-beam system to produce a luminous disturbance in the flow. The time of flight of this disturbance was measured. Experimental tests were conducted in the Langley pilot model expansion tube. The measured velocities were of the order of 6000 m/sec over a free-stream density range from 0.000196 to 0.00186 kg/cu m. The fractional error in the velocity measurements was less than 5 percent. Long arc discharge columns (0.356 m) were generated under hypersonic flow conditions in the expansion-tube modified to operate as an expansion tunnel.

Laser measurements of unsteady flow field in a radial turbine guide vanes

NASA Astrophysics Data System (ADS)

Pasin, M.; Tabakoff, W.

1992-01-01

Detailed measurements of a unsteady flow field within the inlet guide vanes (IGV) of a radial inflow turbine were performed using a three component Laser Doppler Velocimeter (LDV) system. The mean velocity, the flow angle and the turbulence results are presented at the midspan plane for different rotor positions. These results are compared with the measurements obtained in the same passage in the absence of the rotor.

Three-dimensional flow field measurements in a radial inflow turbine scroll using LDV

NASA Technical Reports Server (NTRS)

Malak, M. F.; Hamed, A.; Tabakoff, W.

1986-01-01

The results of an experimental study of the three-dimensional flow field in a radial inflow turbine scroll are presented. A two-color LDV system was used in the measurement of three orthogonal velocity components at 758 points located throughout the scroll and the unvaned portion of the nozzle. The cold flow experimental results are presented for through-flow velocity contours and the cross velocity vectors.

Measuring Taylor Slough boundary and internal flows, Everglades National Park, Florida

USGS Publications Warehouse

Tillis, G.M.

2001-01-01

Four intensive data-collection efforts, intended to represent the spectrum of precipitation events and associated flow conditions, were conducted during 1997 and 1998 in the Taylor Slough Basin, Everglades National Park. Flow velocities were measured by newly developed, portable Acoustic Doppler Velocity meters along three transects bisecting the Taylor Slough Basin from east to west, roughly perpendicular to the centerline axis of the slough as well as a fourth transect along the slough's axis. These meters provided the required levels of accuracy in flow-velocity measurements while enabling the rapid collection of multiple time series of flow data at remote sites. Concurrently, flow measurements were made along bordering road culverts and under L-31W and Taylor Slough bridges. Flows across the study area's boundaries provided net flow of water into the system and transect measurements provided flow data within the basin. Collected data are available through the World Wide Web (http://sofia.usgs.gov/projects/flow_velocity/). The high-water and low-water events corresponded with the highest and lowest flow velocities, respectively. The July 1998 data had lower than expected flow velocities and, in some cases, strong winds reversed flow direction.

Calibration of sonic valves for the laminar flow control, leading-edge flight test

NASA Technical Reports Server (NTRS)

Petley, D. H.; Alexander, W., Jr.; Wright, A. S., Jr.; Vallas, M.

1985-01-01

Sonic needle valves were calibrated to measure and control airflow in the suction system for the leading-edge flight test. The procedure and results for the calibration flow test of 4:41 flight valves are given. Mass-flow rates, which ranged from 0.001 to 0.012 lbm/sec, and maximum back pressure were measured for total temperatures from -30 F to 75 F and total pressures from 120 to 540 psf. Correlating equations are obtained for mass-flow rate as a function of total pressure, total temperature, and valve opening length. The most important aspect of flow measurement and control is found to be the measurement of valve opening length.

Continuous real-time measurement of aqueous cyanide

DOEpatents

Rosentreter, Jeffrey J.; Gering, Kevin L.

2007-03-06

This invention provides a method and system capable of the continuous, real-time measurement of low concentrations of aqueous free cyanide (CN) using an on-line, flow through system. The system is based on the selective reactivity of cyanide anions and the characteristically nonreactive nature of metallic gold films, wherein this selective reactivity is exploited as an indirect measurement for aqueous cyanide. In the present invention the dissolution of gold, due to the solubilization reaction with the analyte cyanide anion, is monitored using a piezoelectric microbalance contained within a flow cell.

40 CFR Appendix E to Part 52 - Performance Specifications and, Specification Test Procedures for Monitoring Systems for Effluent...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., Specification Test Procedures for Monitoring Systems for Effluent Stream Gas Volumetric Flow Rate E Appendix E... Stream Gas Volumetric Flow Rate 1. Principle and applicability. 1.1Principle. Effluent stream gas... method is applicable to subparts which require continuous gas volumetric flow rate measurement...

40 CFR Appendix E to Part 52 - Performance Specifications and, Specification Test Procedures for Monitoring Systems for Effluent...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Specification Test Procedures for Monitoring Systems for Effluent Stream Gas Volumetric Flow Rate E Appendix E... Stream Gas Volumetric Flow Rate 1. Principle and applicability. 1.1Principle. Effluent stream gas... method is applicable to subparts which require continuous gas volumetric flow rate measurement...

Dynamical systems characterization of inertial effects of fluid flow in a curved artery model under pulsatile flow forcing

NASA Astrophysics Data System (ADS)

Leggiero, Michael; Bulusu, Kartik V.; Plesniak, Michael W.

2013-11-01

The main objective of this study was to examine inertial effects in a 180-degree model of curved arteries under pulsatile inflow conditions. Two-component, two-dimensional particle image velocimetery (2C-2D PIV) data were acquired upstream of and at several cross-sectional locations in the curved artery model. A blood-analog fluid comprised of 71% saturated sodium iodide solution, 28% glycerol and 1% distilled water (by volume) was subjected to multi-harmonic pulsatile inflow functions. First, signal time-lag was quantified by cross-correlating the input (voltage-time) supplied to a programmable pump and the output PIV (flow rate-time) measurements. The experiment was then treated as a linear, time-invariant system, and frequency response was estimated for phase shifts across a certain spectrum. Input-output signal dissimilarities were attributable to intrinsic inertial effects of flow. By coupling pressure-time and upstream flow rate-time measurements, the experiment was modeled using system identification methods. Results elucidate the role of inertial effects in fluid flow velocity measurements and the effect of these delays on secondary flow structure detection in a curved artery model. Supported by the NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

Development of a thermal-hydraulics experimental system for high Tc superconductors cooled by liquid hydrogen

NASA Astrophysics Data System (ADS)

Tatsumoto, H.; Shirai, Y.; Shiotsu, M.; Hata, K.; Kobayashi, H.; Naruo, Y.; Inatani, Y.; Kato, T.; Futakawa, M.; Kinoshita, K.

2010-06-01

A thermal-hydraulics experimental system of liquid hydrogen was developed in order to investigate the forced flow heat transfer characteristics in the various cooling channels for wide ranges of subcoolings, flow velocities, and pressures up to supercritical. A main tank is connected to a sub tank through a hydrogen transfer line with a control valve. A channel heater is located at one end of the transfer line in the main tank. Forced flow through the channel is produced by adjusting the pressure difference between the tanks and the valve opening. The mass flow rate is measured from the weight change of the main tank. For the explosion protection, electrical equipments are covered with a nitrogen gas blanket layer and a remote control system was established. The first cryogenic performance tests confirmed that the experimental system had satisfied with the required performances. The forced convection heat transfer characteristics was successfully measured at the pressure of 0.7 MPa for various flow velocities.

In vivo photoacoustic tomography of total blood flow and Doppler angle

NASA Astrophysics Data System (ADS)

Yao, Junjie; Maslov, Konstantin I.; Wang, Lihong V.

2012-02-01

As two hallmarks of cancer, angiogenesis and hypermetabolism are closely related to increased blood flow. Volumetric blood flow measurement is important to understanding the tumor microenvironment and developing new means to treat cancer. Current photoacoustic blood flow estimation methods focus on either the axial or transverse component of the flow vector. Here, we propose a method to compute the total flow speed and Doppler angle by combining the axial and transverse flow measurements. Both the components are measured in M-mode. Collating the A-lines side by side yields a 2D matrix. The columns are Hilbert transformed to compare the phases for the computation of the axial flow. The rows are Fourier transformed to quantify the bandwidth for the computation of the transverse flow. From the axial and transverse flow components, the total flow speed and Doppler angle can be derived. The method has been verified by flowing bovine blood in a plastic tube at various speeds from 0 to 7.5 mm/s and at Doppler angles from 30 to 330°. The measurement error for total flow speed was experimentally determined to be less than 0.3 mm/s; for the Doppler angle, it was less than 15°. In addition, the method was tested in vivo on a mouse ear. The advantage of this method is simplicity: No system modification or additional data acquisition is required to use our existing system. We believe that the proposed method has the potential to be used for cancer angiogenesis and hypermetabolism imaging.

Evaluation of the structures size in the liquid-gas flow by gamma-ray absorption

NASA Astrophysics Data System (ADS)

Zych, Marcin; Hanus, Robert; Jaszczur, Marek; Świsulski, Dariusz; Petryka, Leszek; Jodłowski, Paweł; Zych, Piotr

2018-06-01

The rapid development of tomography methods particularly electrical, X and gamma rays allows for a wide range of the information about flow structure. However, all of such methods are quite complicated. At the same time much simpler systems as the measuring system of gamma rays absorption, allows to obtain a all key flow information which describe the two-phase flow. In the article the results of analyzes of radiometric signal that not only allow to recognize the type of flow, but also the assessment of forming structures are presented. Calculation and interpretation of the data were based on the crosscorrelation and cross-spectral density function. In order to verify the calculations the photographic documentation made during the measurements was used.

Drag measurements on a laminar-flow body of revolution in the 13-inch magnetic suspension and balance system

NASA Technical Reports Server (NTRS)

Dress, David A.

1989-01-01

Low speed wind tunnel drag force measurements were taken on a laminar flow body of revolution free of support interference. This body was tested at zero incidence in the NASA Langley 13 in. Magnetic Suspension and Balance System (MSBS). The primary objective of these tests was to substantiate the drag force measuring capabilities of the 13 in. MSBS. The drag force calibrations and wind-on repeatability data provide a means of assessing these capabilities. Additional investigations include: (1) the effects of fixing transition; (2) the effects of fins installed in the tail; and (3) surface flow visualization using both liquid crystals and oil flow. Also two simple drag prediction codes were used to assess their usefulness in estimating overall body drag.

Wake measurements in a strong adverse pressure gradient

NASA Technical Reports Server (NTRS)

Hoffenberg, R.; Sullivan, John P.; Schneider, S. P.

1994-01-01

The behavior of wakes in adverse pressure gradients is critical to the performance of high-lift systems for transport aircraft. Wake deceleration is known to lead to sudden thickening and the onset of reversed flow; this 'wake bursting' phenomenon can occur while surface flows remain attached. Although 'wake bursting' is known to be important for high-lift systems, no detailed measurements of 'burst' wakes have ever been reported. Wake bursting has been successfully achieved in the wake of a flat plate as it decelerated in a two-dimensional diffuser, whose sidewalls were forced to remain attached by use of slot blowing. Pilot probe surveys, L.D.V. measurements, and flow visualization have been used to investigate the physics of this decelerated wake, through the onset of reversed flow.

CARS Temperature Measurements in a Hypersonic Propulsion Test Facility

NASA Technical Reports Server (NTRS)

Jarrett, Olin, Jr.; Smith, M. W.; Antcliff, R. R.; Northam, G. Burt; Cutler, A. D.; Capriotti, D. P.; Taylor, D. J.

1990-01-01

Nonintrusive diagnostic measurements were performed in the supersonic reacting flow of the Hypersonic Propulsion Test Cell 2 at NASA-Langley. A Coherent Anti-stokes Raman Spectroscopy (CARS) system was assembled specifically for the test cell environment. System design considerations were: (1) test cell noise and vibration; (2) contamination from flow field or atmospheric borne dust; (3) unwanted laser or electrically induced combustion (inside or outside the duct); (4) efficient signal collection; (5) signal splitting to span the wide dynamic range present throughout the flow field; (6) movement of the sampling volume in the flow; and (7) modification of the scramjet model duct to permit optical access to the reacting flow with the CARS system. The flow in the duct was a nominal Mach 2 flow with static pressure near one atmosphere. A single perpendicular injector introduced hydrogen into the flow behind a rearward facing step. CARS data was obtained in three planes downstream of the injection region. At least 20 CARS data points were collected at each of the regularly spaced sampling locations in each data plane. Contour plots of scramjet combustor static temperature in a reacting flow region are presented.

Pneumatic Proboscis Heat-Flow Probe

NASA Technical Reports Server (NTRS)

Zacny, Kris; Hedlund, Magnus; Mumm, Eric; Shasho, Jeffrey; Chu, Philip; Kumar, Nishant

2013-01-01

Heat flow is a fundamental property of a planet, and provides significant constraints on the abundance of radiogenic isotopes, the thermal evolution and differentiation history, and the mechanical properties of the lithosphere. Heat-flow measurements are also essential in achieving at least four of the goals set out by the National Research Council for future lunar exploration. The heat-flow probe therefore directly addresses the goal of the Lunar Geophysical Network, which is to understand the interior structure and composition of the Moon. A key challenge for heat flow measurement is to install thermal sensors to the depths approximately equal to 3 m that are not influenced by the diurnal, annual, and longer-term fluctuations of the surface thermal environment. In addition, once deployed, the heat flow probe should cause little disturbance to the thermal regime of the surrounding regolith. A heat-flow probe system was developed that has two novel features: (1) it utilizes a pneumatic (gas) approach, excavates a hole by lofting the lunar soil out of the hole, and (2) deploys the heat flow probe, which utilizes a coiled up tape as a thermal probe to reach greater than 3-meter depth. The system is a game-changer for small lunar landers as it exhibits extremely low mass, volume, and simple deployment. The pneumatic system takes advantage of the helium gas used for pressurizing liquid propellant of the lander. Normally, helium is vented once the lander is on the surface, but it can be utilized for powering pneumatic systems. Should sufficient helium not be available, a simple gas delivery system may be taken specifically for the heat flow probe. Either way, the pneumatic heat flow probe system would be much lighter than other systems that entirely rely on the electrical power of the lander.

Regional muscle tissue saturation is an indicator of global inadequate circulation during cardiopulmonary bypass: a randomized porcine study using muscle, intestinal and brain tissue metabolomics.

PubMed

Thomassen, Sisse Anette; Kjærgaard, Benedict; Sørensen, Preben; Andreasen, Jan Jesper; Larsson, Anders; Rasmussen, Bodil Steen

2017-04-01

Muscle tissue saturation (StO 2 ) measured with near-infrared spectroscopy has generally been considered a measurement of the tissue microcirculatory condition. However, we hypothesized that StO 2 could be more regarded as a fast and reliable measure of global than of regional circulatory adequacy and tested this with muscle, intestinal and brain metabolomics at normal and two levels of low cardiopulmonary bypass blood flow rates in a porcine model. Twelve 80 kg pigs were connected to normothermic cardiopulmonary bypass with a blood flow of 60 mL/kg/min for one hour, reduced randomly to 47.5 mL/kg/min (Group I) or 35 mL/kg/min (Group II) for one hour followed by one hour of 60 mL/kg/min in both groups. Regional StO 2 was measured continuously above the musculus gracilis (non-cannulated leg). Metabolomics were obtained by brain tissue oxygen monitoring system (Licox) measurements of the brain and microdialysis perfusate from the muscle, intestinal mucosa and brain. A non-parametric statistical method was used. The systemic parameters showed profound systemic ischaemia during low CPB blood flow. StO 2 did not change markedly in Group I, but in Group II, StO 2 decreased immediately when blood flow was reduced and, furthermore, was not restored despite blood flow being normalized. Changes in the metabolomics from the muscle, colon and brain followed the changes in StO 2 . We found, in this experimental cardiopulmonary bypass model, that StO 2 reacted rapidly when the systemic circulation became inadequate and, furthermore, reliably indicate insufficient global tissue perfusion even when the systemic circulation was restored after a period of systemic hypoperfusion.

Development of a Dual-PIV system for high-speed flow applications

NASA Astrophysics Data System (ADS)

Schreyer, Anne-Marie; Lasserre, Jean J.; Dupont, Pierre

2015-10-01

A new Dual-particle image velocimetry (Dual-PIV) system for application in supersonic flows was developed. The system was designed for shock wave/turbulent boundary layer interactions with separation. This type of flow places demanding requirements on the system, from the large range of characteristic frequencies O(100 Hz-100 kHz) to spatial and temporal resolutions necessary for the measurement of turbulent quantities (Dolling in AIAA J 39(8):1517-1531, 2001; Dupont et al. in J Fluid Mech 559:255-277, 2006; Smits and Dussauge in Turbulent shear layers in supersonic flow, 2nd edn. Springer, New York, 2006). While classic PIV systems using high-resolution CCD sensors allow high spatial resolution, these systems cannot provide the required temporal resolution. Existing high-speed PIV systems provide temporal and CMOS sensor resolutions, and even laser pulse energies, that are not adapted to our needs. The only obvious solution allowing sufficiently high spatial resolution, access to high frequencies, and a high laser pulse energy is a multi-frame system: a Dual-PIV system, consisting of two synchronized PIV systems observing the same field of view, will give access to temporal characteristics of the flow. The key technology of our system is frequency-based image separation: two lasers of different wavelengths illuminate the field of view. The cross-pollution with laser light from the respective other branches was quantified during system validation. The overall system noise was quantified, and the prevailing error of only 2 % reflects the good spatial and temporal alignment. The quality of the measurement system is demonstrated with some results on a subsonic jet flow including the spatio-temporal inter-correlation functions between the systems. First measurements in a turbulent flat-plate boundary layer at Mach 2 show the same satisfactory data quality and are also presented and discussed.

Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing

PubMed Central

Liu, Yaxin; Chen, Liguo; Sun, Lining

2009-01-01

A high speed MEMS flow sensor to enhance the reliability and accuracy of a liquid dispensing system is proposed. Benefitting from the sensor information feedback, the system can self-adjust the open time of the solenoid valve to accurately dispense desired volumes of reagent without any pre-calibration. First, an integrated high-speed liquid flow sensor based on the measurement of the pressure difference across a flow channel is presented. Dimensions of the micro-flow channel and two pressure sensors have been appropriately designed to meet the static and dynamic requirements of the liquid dispensing system. Experiments results show that the full scale (FS) flow measurement ranges up to 80 μL/s, with a nonlinearity better than 0.51% FS. Secondly, a novel closed-loop control strategy is proposed to calculate the valve open time in each dispensing cycle, which makes the system immune to liquid viscosity, pressure fluctuation, and other sources of error. Finally, dispensing results show that the system can achieve better dispensing performance, and the coefficient of variance (CV) for liquid dispensing is below 3% at 1 μL and below 4% at 100 nL. PMID:22408517

Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing.

PubMed

Liu, Yaxin; Chen, Liguo; Sun, Lining

2009-01-01

A high speed MEMS flow sensor to enhance the reliability and accuracy of a liquid dispensing system is proposed. Benefitting from the sensor information feedback, the system can self-adjust the open time of the solenoid valve to accurately dispense desired volumes of reagent without any pre-calibration. First, an integrated high-speed liquid flow sensor based on the measurement of the pressure difference across a flow channel is presented. Dimensions of the micro-flow channel and two pressure sensors have been appropriately designed to meet the static and dynamic requirements of the liquid dispensing system. Experiments results show that the full scale (FS) flow measurement ranges up to 80 μL/s, with a nonlinearity better than 0.51% FS. Secondly, a novel closed-loop control strategy is proposed to calculate the valve open time in each dispensing cycle, which makes the system immune to liquid viscosity, pressure fluctuation, and other sources of error. Finally, dispensing results show that the system can achieve better dispensing performance, and the coefficient of variance (CV) for liquid dispensing is below 3% at 1 μL and below 4% at 100 nL.

The Tacitness of Tacitus. A Methodological Approach to European Thought. No. 46.

ERIC Educational Resources Information Center

Bierschenk, Bernhard

This study measured the analysis of verbal flows by means of volume-elasticity measures and the analysis of information flow structures and their representations in the form of a metaphysical cube. A special purpose system of computer programs (PERTEX) was used to establish the language space in which the textual flow patterns occurred containing…

Device accurately measures and records low gas-flow rates

NASA Technical Reports Server (NTRS)

Branum, L. W.

1966-01-01

Free-floating piston in a vertical column accurately measures and records low gas-flow rates. The system may be calibrated, using an adjustable flow-rate gas supply, a low pressure gage, and a sequence recorder. From the calibration rates, a nomograph may be made for easy reduction. Temperature correction may be added for further accuracy.

The Development of Point Doppler Velocimeter Data Acquisition and Processing Software

NASA Technical Reports Server (NTRS)

Cavone, Angelo A.

2008-01-01

In order to develop efficient and quiet aircraft and validate Computational Fluid Dynamic predications, aerodynamic researchers require flow parameter measurements to characterize flow fields about wind tunnel models and jet flows. A one-component Point Doppler Velocimeter (pDv), a non-intrusive, laser-based instrument, was constructed using a design/develop/test/validate/deploy approach. A primary component of the instrument is software required for system control/management and data collection/reduction. This software along with evaluation algorithms, advanced pDv from a laboratory curiosity to a production level instrument. Simultaneous pDv and pitot probe velocity measurements obtained at the centerline of a flow exiting a two-inch jet, matched within 0.4%. Flow turbulence spectra obtained with pDv and a hot-wire detected the primary and secondary harmonics with equal dynamic range produced by the fan driving the flow. Novel,hardware and software methods were developed, tested and incorporated into the system to eliminate and/or minimize error sources and improve system reliability.

Active Flow Control on a Boundary-Layer-Ingesting Inlet

NASA Technical Reports Server (NTRS)

Gorton, Susan Althoff; Owens, Lewis R.; Jenkins, Luther N.; Allan, Brian G.; Schuster, Ernest P.

2004-01-01

Boundary layer ingestion (BLI) is explored as means to improve overall system performance for Blended Wing Body configuration. The benefits of BLI for vehicle system performance benefit are assessed with a process derived from first principles suitable for highly-integrated propulsion systems. This performance evaluation process provides framework within which to assess the benefits of an integrated BLI inlet and lays the groundwork for higher-fidelity systems studies. The results of the system study show that BLI provides a significant improvement in vehicle performance if the inlet distortion can be controlled, thus encouraging the pursuit of active flow control (AFC) as a BLI enabling technology. The effectiveness of active flow control in reducing engine inlet distortion was assessed using a 6% scale model of a 30% BLI offset, diffusing inlet. The experiment was conducted in the NASA Langley Basic Aerodynamics Research Tunnel with a model inlet designed specifically for this type of testing. High mass flow pulsing actuators provided the active flow control. Measurements were made of the onset boundary layer, the duct surface static pressures, and the mass flow through the duct and the actuators. The distortion was determined by 120 total pressure measurements located at the aerodynamic interface plane. The test matrix was limited to a maximum freestream Mach number of 0.15 with scaled mass flows through the inlet for that condition. The data show that the pulsed actuation can reduce distortion from 29% to 4.6% as measured by the circumferential distortion descriptor DC60 using less than 1% of inlet mass flow. Closed loop control of the actuation was also demonstrated using a sidewall surface static pressure as the response sensor.

A new approach for flow-through respirometry measurements in humans

PubMed Central

Ingebrigtsen, Jan P.; Bergouignan, Audrey; Ohkawara, Kazunori; Kohrt, Wendy M.; Lighton, John R. B.

2010-01-01

Indirect whole room calorimetry is commonly used in studies of human metabolism. These calorimeters can be configured as either push or pull systems. A major obstacle to accurately calculating gas exchange rates in a pull system is that the excurrent flow rate is increased above the incurrent flow rate, because the organism produces water vapor, which also dilutes the concentrations of respiratory gasses in the excurrent sample. A common approach to this problem is to dry the excurrent gasses prior to measurement, but if drying is incomplete, large errors in the calculated oxygen consumption will result. The other major potential source of error is fluctuations in the concentration of O2 and CO2 in the incurrent airstream. We describe a novel approach to measuring gas exchange using a pull-type whole room indirect calorimeter. Relative humidity and temperature of the incurrent and excurrent airstreams are measured continuously using high-precision, relative humidity and temperature sensors, permitting accurate measurement of water vapor pressure. The excurrent flow rates are then adjusted to eliminate the flow contribution from water vapor, and respiratory gas concentrations are adjusted to eliminate the effect of water vapor dilution. In addition, a novel switching approach is used that permits constant, uninterrupted measurement of the excurrent airstream while allowing frequent measurements of the incurrent airstream. To demonstrate the accuracy of this approach, we present the results of validation trials compared with our existing system and metabolic carts, as well as the results of standard propane combustion tests. PMID:20200135

Noninvasive blood-flow meter using a curved cannula with zero compensation for an axial flow blood pump.

PubMed

Kosaka, Ryo; Fukuda, Kyohei; Nishida, Masahiro; Maruyama, Osamu; Yamane, Takashi

2013-01-01

In order to monitor the condition of a patient using a left ventricular assist system (LVAS), blood flow should be measured. However, the reliable determination of blood-flow rate has not been established. The purpose of the present study is to develop a noninvasive blood-flow meter using a curved cannula with zero compensation for an axial flow blood pump. The flow meter uses the centrifugal force generated by the flow rate in the curved cannula. Two strain gauges served as sensors. The first gauges were attached to the curved area to measure static pressure and centrifugal force, and the second gauges were attached to straight area to measure static pressure. The flow rate was determined by the differences in output from the two gauges. The zero compensation was constructed based on the consideration that the flow rate could be estimated during the initial driving condition and the ventricular suction condition without using the flow meter. A mock circulation loop was constructed in order to evaluate the measurement performance of the developed flow meter with zero compensation. As a result, the zero compensation worked effectively for the initial calibration and the zero-drift of the measured flow rate. We confirmed that the developed flow meter using a curved cannula with zero compensation was able to accurately measure the flow rate continuously and noninvasively.

Experimental and numerical characterization of the water flow in spacer-filled channels of spiral-wound membranes.

PubMed

Bucs, Szilard S; Linares, Rodrigo Valladares; Marston, Jeremy O; Radu, Andrea I; Vrouwenvelder, Johannes S; Picioreanu, Cristian

2015-12-15

Micro-scale flow distribution in spacer-filled flow channels of spiral-wound membrane modules was determined with a particle image velocimetry system (PIV), aiming to elucidate the flow behaviour in spacer-filled flow channels. Two-dimensional water velocity fields were measured in a flow cell (representing the feed spacer-filled flow channel of a spiral wound reverse osmosis membrane module without permeate production) at several planes throughout the channel height. At linear flow velocities (volumetric flow rate per cross-section of the flow channel considering the channel porosity, also described as crossflow velocities) used in practice (0.074 and 0.163 m·s(-1)) the recorded flow was laminar with only slight unsteadiness in the upper velocity limit. At higher linear flow velocity (0.3 m·s(-1)) the flow was observed to be unsteady and with recirculation zones. Measurements made at different locations in the flow cell exhibited very similar flow patterns within all feed spacer mesh elements, thus revealing the same hydrodynamic conditions along the length of the flow channel. Three-dimensional (3-D) computational fluid dynamics simulations were performed using the same geometries and flow parameters as the experiments, based on steady laminar flow assumption. The numerical results were in good agreement (0.85-0.95 Bray-Curtis similarity) with the measured flow fields at linear velocities of 0.074 and 0.163 m·s(-1), thus supporting the use of model-based studies in the optimization of feed spacer geometries and operational conditions of spiral wound membrane systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Computed tomography measurement of gaseous fuel concentration by infrared laser light absorption

NASA Astrophysics Data System (ADS)

Kawazoe, Hiromitsu; Inagaki, Kazuhisa; Emi, Y.; Yoshino, Fumio

1997-11-01

A system to measure gaseous hydrocarbon distributions was devised, which is based on IR light absorption by C-H stretch mode of vibration and computed tomography method. It is called IR-CT method in the paper. Affection of laser light power fluctuation was diminished by monitoring source light intensity by the second IR light detector. Calibration test for methane fuel was carried out to convert spatial data of line absorption coefficient into quantitative methane concentration. This system was applied to three flow fields. The first is methane flow with lifted flame which is generated by a gourd-shaped fuel nozzle. Feasibility of the IR-CT method was confirmed through the measurement. The second application is combustion field with diffusion flame. Calibration to determine absorptivity was undertaken, and measured line absorption coefficient was converted spatial fuel concentration using corresponding temperature data. The last case is modeled in cylinder gas flow of internal combustion engine, where gaseous methane was led to the intake valve in steady flow state. The fuel gas flow simulates behavior of gaseous gasoline which is evaporated at intake valve tulip. Computed tomography measurement of inner flow is essentially difficult because of existence of surrounding wall. In this experiment, IR laser beam was led to planed portion by IR light fiber. It is found that fuel convection by airflow takes great part in air-fuel mixture formation and the developed IR-CT system to measure fuel concentration is useful to analyze air-fuel mixture formation process and to develop new combustors.

Development of an in-vitro circulatory system with known resistance and capacitance

NASA Technical Reports Server (NTRS)

Offerdahl, C. D.; Schaub, J. D.; Koenig, S. C.; Swope, R. D.; Ewert, D. L.; Convertino, V. A. (Principal Investigator)

1996-01-01

An in-vitro (hydrodynamic) model of the circulatory system was developed. The model consisted of a pump, compliant tubing, and valves for resistance. The model is used to simulate aortic pressure and flow. These parameters were measured using a Konigsburg Pressure transducer and a Triton ART2 flow probe. In addition, venous pressure and flow were measured on the downstream side of the resistance. The system has a known compliance and resistance. Steady and pulsatile flow tests were conducted to determine the resistance of the model. A static compliance test was used to determine the compliance of the system. The aortic pressure and flow obtained from the hydrodynamic model will be used to test the accuracy of parameter estimation models such as the 2-element and 4-element Windkessel models and the 3-element Westkessel model. Verifying analytical models used in determining total peripheral resistance (TPR) and systemic arterial compliance (SAC) is important because it provides insight into hemodynamic parameters that indicate baroreceptor responsiveness to situations such as changes in gravitational acceleration.

Numerical simulation of the effect of upstream swirling flow on swirl meter performance

NASA Astrophysics Data System (ADS)

Chen, Desheng; Cui, Baoling; Zhu, Zuchao

2018-04-01

Flow measurement is important in the fluid process and transmission system. For the need of accuracy measurement of fluid, stable flow is acquired. However, the elbows and devices as valves and rotary machines may produce swirling flow in the natural gas pipeline networks system and many other industry fields. In order to reveal the influence of upstream swirling flow on internal flow fields and the metrological characteristics, numerical simulations are carried out on the swirl meter. Using RNG k-ɛ turbulent model and SIMPLE algorithm, the flow field is numerically simulated under swirling flows generated from co-swirl and counter-swirl flow. Simulation results show fluctuation is enhanced or weakened depending on the rotating direction of swirling flow. A counter- swirl flow increases the entropy production rate at the inlet and outlet of the swirler, the junction region between throat and divergent section, and then the pressure loss is increased. The vortex precession dominates the static pressure distributions on the solid walls and in the channel, especially at the end region of the throat.

Force measuring valve assemblies, systems including such valve assemblies and related methods

DOEpatents

DeWall, Kevin George [Pocatello, ID; Garcia, Humberto Enrique [Idaho Falls, ID; McKellar, Michael George [Idaho Falls, ID

2012-04-17

Methods of evaluating a fluid condition may include stroking a valve member and measuring a force acting on the valve member during the stroke. Methods of evaluating a fluid condition may include measuring a force acting on a valve member in the presence of fluid flow over a period of time and evaluating at least one of the frequency of changes in the measured force over the period of time and the magnitude of the changes in the measured force over the period of time to identify the presence of an anomaly in a fluid flow and, optionally, its estimated location. Methods of evaluating a valve condition may include directing a fluid flow through a valve while stroking a valve member, measuring a force acting on the valve member during the stroke, and comparing the measured force to a reference force. Valve assemblies and related systems are also disclosed.

Liquid Bismuth Propellant Management System for the Very High Specific Impulse Thruster with Anode Layer

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Markusic, T. E.; Stanojev, B. J.

2007-01-01

Two prototype bismuth propellant feed systems were constructed and operated in conjunction with a propellant vaporizer. One system provided bismuth to a vaporizer using gas pressurization but did not include a means to measure the flow rate. The second system incorporated an electromagnetic pump to provide fine control of the hydrostatic pressure and a new type of in-line flow sensor that was developed for accurate, real-time measurement of the mass flow rate. High-temperature material compatibility was a driving design requirement for the pump and flow sensor, leading to the selection of Macor for the main body of both components. Posttest inspections of both components revealed no degradation of the material. The gas pressurization system demonstrated continuous pressure control over a range from zero to 200 torr. In separate proof-of-concept experiments, the electromagnetic pump produced a linear pressure rise as a function of current that compared favorably with theoretical pump pressure predictions, producing a pressure rise of 10 kPa at 30 A. Preliminary flow sensor operation indicated a bismuth flow rate of 6 mg/s with an uncertainty of plus or minus 6%. An electronics suite containing a real-time controller was successfully used to control the entire system, simultaneously monitoring all power supplies and performing data acquisition duties.

A flux monitoring method for easy and accurate flow rate measurement in pressure-driven flows.

PubMed

Siria, Alessandro; Biance, Anne-Laure; Ybert, Christophe; Bocquet, Lydéric

2012-03-07

We propose a low-cost and versatile method to measure flow rate in microfluidic channels under pressure-driven flows, thereby providing a simple characterization of the hydrodynamic permeability of the system. The technique is inspired by the current monitoring method usually employed to characterize electro-osmotic flows, and makes use of the measurement of the time-dependent electric resistance inside the channel associated with a moving salt front. We have successfully tested the method in a micrometer-size channel, as well as in a complex microfluidic channel with a varying cross-section, demonstrating its ability in detecting internal shape variations.

Immersed transient eddy current flow metering: a calibration-free velocity measurement technique for liquid metals

NASA Astrophysics Data System (ADS)

Krauter, N.; Stefani, F.

2017-10-01

Eddy current flow meters are widely used for measuring the flow velocity of electrically conducting fluids. Since the flow induced perturbations of a magnetic field depend both on the geometry and the conductivity of the fluid, extensive calibration is needed to get accurate results. Transient eddy current flow metering has been developed to overcome this problem. It relies on tracking the position of an impressed eddy current system that is moving with the same velocity as the conductive fluid. We present an immersed version of this measurement technique and demonstrate its viability by numerical simulations and a first experimental validation.

Simultaneous Measurements of Geometric and Viscoelastic Properties of Hydrogel Microbeads Using Continuous-Flow Microfluidics with Embedded Electrodes.

PubMed

Niu, Ye; Zhang, Xu; Si, Ting; Zhang, Yuntian; Qi, Lin; Zhao, Gang; Xu, Ronald X; He, Xiaoming; Zhao, Yi

2017-12-01

Geometric and mechanical characterizations of hydrogel materials at the microscale are attracting increasing attention due to their importance in tissue engineering, regenerative medicine, and drug delivery applications. Contemporary approaches for measuring the these properties of hydrogel microbeads suffer from low-throughput, complex system configuration, and measurement inaccuracy. In this work, a continuous-flow device is developed to measure geometric and viscoelastic properties of hydrogel microbeads by flowing the microbeads through a tapered microchannel with an array of interdigitated microelectrodes patterned underneath the channel. The viscoelastic properties are derived from the trajectories of microbeads using a quasi-linear viscoelastic model. The measurement is independent of the applied volumetric flow rate. The results show that the geometric and viscoelastic properties of Ca-alginate hydrogel microbeads can be determined independently and simultaneously. The bulky high-speed optical systems are eliminated, simplifying the system configuration and making it a truly miniaturized device. A throughput of up to 394 microbeads min -1 is achieved. This study may provide a powerful tool for mechanical profiling of hydrogel microbeads to support their wide applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flow Visualization Studies in the Novacor Left Ventricular Assist System CRADA PC91-002, Final Report

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

Borovetz, H.S.; Shaffer, F.; Schaub, R.

This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical imaging technique called fluorescent image tracking velocimetry (FITV) to hack the motion of small, neutrally-buoyant particles in a flowing fluid.

Digital holographic microscopy applied to measurement of a flow in a T-shaped micromixer

NASA Astrophysics Data System (ADS)

Ooms, T. A.; Lindken, R.; Westerweel, J.

2009-12-01

In this paper, we describe measurements of a three-dimensional (3D) flow in a T-shaped micromixer by means of digital holographic microscopy. Imaging tracer particles in a microscopic flow with conventional microscopy is accompanied by a small depth-of-field, which hinders true volumetric flow measurements. In holographic microscopy, the depth of the measurement domain does not have this limitation because any desired image plane can be reconstructed after recording. Our digital holographic microscope (DHM) consists of a conventional in-line recording system with an added magnifying optical element. The measured flow velocity and the calculated vorticity illustrate four streamwise vortices in the micromixer outflow channel. Because the investigated flow is stationary and strongly 3D, the DHM performance (i.e. accuracy and resolution) can be precisely investigated. The obtained Dynamic spatial range and Dynamic velocity range are larger than 20 and 30, respectively. High-speed multiple-frame measurements illustrate the capability to simultaneously track about 80 particles in a volumetric measurement domain.

Apparatus for passive removal of subsurface contaminants and mass flow measurement

DOEpatents

Jackson, Dennis G [Augusta, GA; Rossabi, Joseph [Aiken, SC; Riha, Brian D [Augusta, GA

2003-07-15

A system for improving the Baroball valve and a method for retrofitting an existing Baroball valve. This invention improves upon the Baroball valve by reshaping the interior chamber of the valve to form a flow meter measuring chamber. The Baroball valve sealing mechanism acts as a rotameter bob for determining mass flow rate through the Baroball valve. A method for retrofitting a Baroball valve includes providing static pressure ports and connecting a measuring device, to these ports, for measuring the pressure differential between the Baroball chamber and the well. A standard curve of nominal device measurements allows the mass flow rate to be determined through the retrofitted Baroball valve.

Apparatus for passive removal of subsurface contaminants and volume flow measurement

DOEpatents

Jackson, Dennis G.; Rossabi, Joseph; Riha, Brian D.

2002-01-01

A system for improving the Baroball valve and a method for retrofitting an existing Baroball valve. This invention improves upon the Baroball valve by reshaping the interior chamber of the valve to form a flow meter measuring chamber. The Baroball valve sealing mechanism acts as a rotameter bob for determining volume flow rate through the Baroball valve. A method for retrofitting a Baroball valve includes providing static pressure ports and connecting a measuring device, to these ports, for measuring the pressure differential between the Baroball chamber and the well. A standard curve of nominal device measurements allows the volume flow rate to be determined through the retrofitted Baroball valve.

A translating stage system for µ-PIV measurements surrounding the tip of a migrating semi-infinite bubble.

PubMed

Smith, B J; Yamaguchi, E; Gaver, D P

2010-01-01

We have designed, fabricated and evaluated a novel translating stage system (TSS) that augments a conventional micro particle image velocimetry (µ-PIV) system. The TSS has been used to enhance the ability to measure flow fields surrounding the tip of a migrating semi-infinite bubble in a glass capillary tube under both steady and pulsatile reopening conditions. With conventional µ-PIV systems, observations near the bubble tip are challenging because the forward progress of the bubble rapidly sweeps the air-liquid interface across the microscopic field of view. The translating stage mechanically cancels the mean bubble tip velocity, keeping the interface within the microscope field of view and providing a tenfold increase in data collection efficiency compared to fixed-stage techniques. This dramatic improvement allows nearly continuous observation of the flow field over long propagation distances. A large (136-frame) ensemble-averaged velocity field recorded with the TSS near the tip of a steadily migrating bubble is shown to compare well with fixed-stage results under identical flow conditions. Use of the TSS allows the ensemble-averaged measurement of pulsatile bubble propagation flow fields, which would be practically impossible using conventional fixed-stage techniques. We demonstrate our ability to analyze these time-dependent two-phase flows using the ensemble-averaged flow field at four points in the oscillatory cycle.

Stable Algorithm For Estimating Airdata From Flush Surface Pressure Measurements

NASA Technical Reports Server (NTRS)

Whitmore, Stephen, A. (Inventor); Cobleigh, Brent R. (Inventor); Haering, Edward A., Jr. (Inventor)

2001-01-01

An airdata estimation and evaluation system and method, including a stable algorithm for estimating airdata from nonintrusive surface pressure measurements. The airdata estimation and evaluation system is preferably implemented in a flush airdata sensing (FADS) system. The system and method of the present invention take a flow model equation and transform it into a triples formulation equation. The triples formulation equation eliminates the pressure related states from the flow model equation by strategically taking the differences of three surface pressures, known as triples. This triples formulation equation is then used to accurately estimate and compute vital airdata from nonintrusive surface pressure measurements.

Report of secondary flows, boundary layers, turbulence and wave team, report 1

NASA Technical Reports Server (NTRS)

Scoggins, J. R.; Fitzjarrald, D.; Doviak, R.; Cliff, W.

1980-01-01

General criteria for a flight test option are that: (1) there be a good opportunity for comparison with other measurement techniques; (2) the flow to be measured is of considerable scientific or practical interest; and (3) the airborne laser Doppler system is well suited to measure the required quantities. The requirement for comparison, i.e., ground truth, is particularly important because this is the first year of operation for the system. It is necessary to demonstrate that the system does actually measure the winds and compare the results with other methods to provide a check on the system error analysis. The uniqueness of the laser Doppler system precludes any direct comparison, but point measurements from tower mounted wind sensors and two dimensional fields obtained from radars with substantially different sampling volumes are quite useful.

Drag coefficients for loose reactor parts

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

Shi, L.; Doster, J.M.; Mayo, C.W.

1997-12-01

Loose-part monitoring systems are capable of providing estimates of loose-part mass and energy as well as impact location. Additional information regarding potentially damaging loose parts can be obtained by estimating loose-part velocity on the basis of free motion dynamics within the flow. To estimate the loose-part velocity, the drag coefficient of the part must be known. Traditionally, drag coefficients of three-dimensional bodies are measured in wind tunnels, by towing in free air or liquids, and with drop tests. These methods have disadvantages with respect to measuring drag coefficients for loose parts in that they require a fixed orientation, or themore » flow field is inconsistent with the turbulent flow conditions found in reactor systems. Though drag coefficients for some regularly shaped objects can be found in the literature, many shapes representative of typical loose parts have not been investigated. In this work, drag coefficients are measured for typical loose-part shapes, including bolts, nuts, pins, and hand tools within the flow conditions expected in reactor coolant systems.« less

Comparison of Stereo-PIV and Plenoptic-PIV Measurements on the Wake of a Cylinder in NASA Ground Test Facilities.

NASA Technical Reports Server (NTRS)

Fahringer, Timothy W.; Thurow, Brian S.; Humphreys, William M., Jr.; Bartram, Scott M.

2017-01-01

A series of comparison experiments have been performed using a single-camera plenoptic PIV measurement system to ascertain the systems performance capabilities in terms of suitability for use in NASA ground test facilities. A proof-of-concept demonstration was performed in the Langley Advanced Measurements and Data Systems Branch 13-inch (33- cm) Subsonic Tunnel to examine the wake of a series of cylinders at a Reynolds number of 2500. Accompanying the plenoptic-PIV measurements were an ensemble of complementary stereo-PIV measurements. The stereo-PIV measurements were used as a truth measurement to assess the ability of the plenoptic-PIV system to capture relevant 3D/3C flow field features in the cylinder wake. Six individual tests were conducted as part of the test campaign using three different cylinder diameters mounted in two orientations in the tunnel test section. This work presents a comparison of measurements with the cylinders mounted horizontally (generating a 2D flow field in the x-y plane). Results show that in general the plenoptic-PIV measurements match those produced by the stereo-PIV system. However, discrepancies were observed in extracted pro les of the fuctuating velocity components. It is speculated that spatial smoothing of the vector fields in the stereo-PIV system could account for the observed differences. Nevertheless, the plenoptic-PIV system performed extremely well at capturing the flow field features of interest and can be considered a viable alternative to traditional PIV systems in smaller NASA ground test facilities with limited optical access.

A dual-phantom system for validation of velocity measurements in stenosis models under steady flow.

PubMed

Blake, James R; Easson, William J; Hoskins, Peter R

2009-09-01

A dual-phantom system is developed for validation of velocity measurements in stenosis models. Pairs of phantoms with identical geometry and flow conditions are manufactured, one for ultrasound and one for particle image velocimetry (PIV). The PIV model is made from silicone rubber, and a new PIV fluid is made that matches the refractive index of 1.41 of silicone. Dynamic scaling was performed to correct for the increased viscosity of the PIV fluid compared with that of the ultrasound blood mimic. The degree of stenosis in the models pairs agreed to less than 1%. The velocities in the laminar flow region up to the peak velocity location agreed to within 15%, and the difference could be explained by errors in ultrasound velocity estimation. At low flow rates and in mild stenoses, good agreement was observed in the distal flow fields, excepting the maximum velocities. At high flow rates, there was considerable difference in velocities in the poststenosis flow field (maximum centreline differences of 30%), which would seem to represent real differences in hydrodynamic behavior between the two models. Sources of error included: variation of viscosity because of temperature (random error, which could account for differences of up to 7%); ultrasound velocity estimation errors (systematic errors); and geometry effects in each model, particularly because of imperfect connectors and corners (systematic errors, potentially affecting the inlet length and flow stability). The current system is best placed to investigate measurement errors in the laminar flow region rather than the poststenosis turbulent flow region.

NMRI Measurements of Flow of Granular Mixtures

NASA Technical Reports Server (NTRS)

Nakagawa, Masami; Waggoner, R. Allen; Fukushima, Eiichi

1996-01-01

We investigate complex 3D behavior of granular mixtures in shaking and shearing devices. NMRI can non-invasively measure concentration, velocity, and velocity fluctuations of flows of suitable particles. We investigate origins of wall-shear induced convection flow of single component particles by measuring the flow and fluctuating motion of particles near rough boundaries. We also investigate if a mixture of different size particles segregate into their own species under the influence of external shaking and shearing disturbances. These non-invasive measurements will reveal true nature of convecting flow properties and wall disturbance. For experiments in a reduced gravity environment, we will design a light weight NMR imager. The proof of principle development will prepare for the construction of a complete spaceborne system to perform experiments in space.

Velocity and pressure measurements in guide vane clearance gap of a low specific speed Francis turbine

NASA Astrophysics Data System (ADS)

Thapa, B. S.; Dahlhaug, O. G.; Thapa, B.

2016-11-01

In Francis turbine, a small clearance gap between the guide vanes and the cover plates is usually required to pivot guide vanes as a part of governing system. Deflection of cover plates and erosion of mating surfaces causes this gap to increase from its design value. The clearance gap induces the secondary flow in the distributor system. This effects the main flow at the runner inlet, which causes losses in efficiency and instability. A guide vane cascade of a low specific speed Francis turbine has been developed for experimental investigations. The test setup is able to produce similar velocity distributions at the runner inlet as that of a reference prototype turbine. The setup is designed for particle image velocimetry (PIV) measurements from the position of stay vane outlet to the position of runner inlet. In this study, velocity and pressure measurements are conducted with 2 mm clearance gap on one side of guide vane. Leakage flow is observed and measured together with pressure measurements. It is concluded that the leakage flow behaves as a jet and mixes with the main flow in cross-wise direction and forms a vortex filament. This causes non-uniform inlet flow conditions at runner blades.

Two-phase flow characterization based on advanced instrumentation, neural networks, and mathematical modeling

NASA Astrophysics Data System (ADS)

Mi, Ye

1998-12-01

The major objective of this thesis is focused on theoretical and experimental investigations of identifying and characterizing vertical and horizontal flow regimes in two-phase flows. A methodology of flow regime identification with impedance-based neural network systems and a comprehensive model of vertical slug flow have been developed. Vertical slug flow has been extensively investigated and characterized with geometric, kinematic and hydrodynamic parameters. A multi-sensor impedance void-meter and a multi-sensor magnetic flowmeter were developed. The impedance void-meter was cross-calibrated with other reliable techniques for void fraction measurements. The performance of the impedance void-meter to measure the void propagation velocity was evaluated by the drift flux model. It was proved that the magnetic flowmeter was applicable to vertical slug flow measurements. Separable signals from these instruments allow us to unearth most characteristics of vertical slug flow. A methodology of vertical flow regime identification was developed. Supervised neural network and self-organizing neural network systems were employed. First, they were trained with results from an idealized simulation of impedance in a two-phase mixture. The simulation was mainly based on Mishima and Ishii's flow regime map, the drift flux model, and the newly developed model of slug flow. Then, these trained systems were tested with impedance signals. The results showed that the neural network systems were appropriate classifiers of vertical flow regimes. The theoretical models and experimental databases used in the simulation were reliable. Furthermore, this approach was applied successfully to horizontal flow identification. A comprehensive model was developed to predict important characteristics of vertical slug flow. It was realized that the void fraction of the liquid slug is determined by the relative liquid motion between the Taylor bubble tail and the Taylor bubble wake. Relying on this understanding and experimental results, a special relationship was built for the void fraction of the liquid slug. The prediction of the void fraction of the liquid slug was considerably improved. Experimental characterization of vertical slug flows was performed extensively with the impedance void-meter and the magnetic flowmeter. The theoretical predictions were compared with the experimental results. The agreements between them are very satisfactory.

Drag measurements on a laminar flow body of revolution in Langley's 13 inch magnetic suspension and balance system. M.S. Thesis

NASA Technical Reports Server (NTRS)

Dress, David A.

1988-01-01

Low-speed wind tunnel drag force measurements were taken on a laminar flow body of revolution free of support interference. This body was tested at zero incidence in the NASA Langley 13 inch Magnetic Suspension and Balance System (MSBS). The primary objective of these tests was to substantiate the drag force measuring capabilities of the 13 inch MSBS. A secondary objective was to obtain support interference free drag measurements on an axisymmetric body of interest. Both objectives were met. The drag force calibrations and wind-on repeatability data provide a means of assessing the drag force measuring capabilities of the 13 inch MSBS. The measured drag coefficients for this body are of interest to researchers actively involved in designing minimum drag fuselage shapes. Additional investigations included: the effects of fixing transition; the effects of fins installed in the tail; surface flow visualizations using both liquid crystals and oil flow; and base pressure measurements using a one-channel telemetry system. Two drag prediction codes were used to assess their usefulness in estimating overall body drag. These theoretical results did not compare well with the measured values because of the following: incorrect or non-existent modeling of a laminar separation bubble on the body and incorrect of non-existent estimates of base pressure drag.

PIV Measurement of Transient 3-D (Liquid and Gas Phases) Flow Structures Created by a Spreading Flame over 1-Propanol

NASA Technical Reports Server (NTRS)

Hassan, M. I.; Kuwana, K.; Saito, K.

2001-01-01

In the past, we measured three-D flow structure in the liquid and gas phases that were created by a spreading flame over liquid fuels. In that effort, we employed several different techniques including our original laser sheet particle tracking (LSPT) technique, which is capable of measuring transient 2-D flow structures. Recently we obtained a state-of-the-art integrated particle image velocimetry (IPIV), whose function is similar to LSPT, but it has an integrated data recording and processing system. To evaluate the accuracy of our IPIV system, we conducted a series of flame spread tests using the same experimental apparatus that we used in our previous flame spread studies and obtained a series of 2-D flow profiles corresponding to our previous LSPT measurements. We confirmed that both LSPT and IPIV techniques produced similar data, but IPIV data contains more detailed flow structures than LSPT data. Here we present some of newly obtained IPIV flow structure data, and discuss the role of gravity in the flame-induced flow structures. Note that the application of IPIV to our flame spread problems is not straightforward, and it required several preliminary tests for its accuracy including this IPIV comparison to LSPT.

In vitro evaluation of forward and reverse volumetric flow across a regurgitant aortic valve using Doppler power-weighted mean velocities.

PubMed

Minich, L L; Tani, L Y; Pantalos, G M

1997-01-01

To determine the accuracy of using power-weighted mean velocities for quantitating volumetric flow across a cardiac valve, we equipped pulsatile flow-tank systems with a 25 mm porcine or a 27 mm mechanical valve with various sizes of regurgitant orifices. Forward and reverse volumetric flows were measured over a range of hemodynamic conditions using two insonating angles (0 and 45 degrees). Pulsed Doppler power-weighted mean velocity measurements were obtained simultaneously with electromagnetic or ultrasonic transit-time probe measurements. For the porcine valve, Doppler measurements correlated well with electromagnetic flow measurements for all (r = 0.75 to 0.97, p < 0.05) except the smallest (2.7 mm) orifice (r = 0.19). For the mechanical valve, power-weighted mean velocity measurements correlated well with ultrasonic transit-time measurements for each hemodynamic condition defined by pulse rate, mean arterial pressure, and insonating angle (r = 0.93 to 0.99, p < 0.01), but equations varied unpredictably. Thus, although power-weighted mean velocity volumetric flow measurements correlate well with flow probe measurements, equations vary widely as hemodynamic conditions change. Because of this variation, power-weighted mean velocity data are not useful for quantitation of volumetric flow across a cardiac valve at this time. Further investigation may show how different hemodynamic conditions affect power-weighted mean velocity measurements of volumetric flow.

Using archived ITS data to measure the operational benefits of a system-wide adaptive ramp metering system : appendix online 5 : I-205 NB ramp flow & ML speed-flow plots.

DOT National Transportation Integrated Search

2008-12-01

The appendix includes various ramp flow and ML speed-flow plots, including: I-205 NB, Gladstone MP 11.05; I-205 NB, Gladstone Hway MP 12.94; I-205 NB, Lawnfield MP 13.58; I-205 NB, Sunnybrook MP 14.32; I-205 NB, Sunnyside MP 14.7; I-205 NB, Johnson C...

Optical Feedback Interferometry for Velocity Measurement of Parallel Liquid-Liquid Flows in a Microchannel

PubMed Central

Ramírez-Miquet, Evelio E.; Perchoux, Julien; Loubière, Karine; Tronche, Clément; Prat, Laurent; Sotolongo-Costa, Oscar

2016-01-01

Optical feedback interferometry (OFI) is a compact sensing technique with recent implementation for flow measurements in microchannels. We propose implementing OFI for the analysis at the microscale of multiphase flows starting with the case of parallel flows of two immiscible fluids. The velocity profiles in each phase were measured and the interface location estimated for several operating conditions. To the authors knowledge, this sensing technique is applied here for the first time to multiphase flows. Theoretical profiles issued from a model based on the Couette viscous flow approximation reproduce fairly well the experimental results. The sensing system and the analysis presented here provide a new tool for studying more complex interactions between immiscible fluids (such as liquid droplets flowing in a microchannel). PMID:27527178

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

PubMed Central

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 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. PMID:23594816

A Constant-Field Interrupted Resonance System for Percutaneous Electromagnetic Measurement of Blood Flow

PubMed Central

Kolin, Alexander; Steele, James R.; Imai, James S.; Macalpin, Rex N.

1974-01-01

A combination of deformable flow probes of negligible lateral dimensions with an electronic circuit capable of providing a prolonged plateau of dB/dt = 0 and of sampling the flow signal at the end of this interval permits electromagnetic measurement of blood flow with a reliable zero base line secured by switching off the magnet. An extracorporeal magnet provides the magnetic field. The flow transducer is introduced into the vascular system percutaneously through a standard angiographic catheter by conventional technique. The idea of the current generator can be described as “principle of interrupted resonance.” The current wave form can be described as a sequence of disconnected bisected sine waves joined at the apices by horizontal current plateaus where di/dt is strictly zero. Images PMID:4275395

Ultrasonic Blood Flow Measurement in Haemodialysis

PubMed Central

Sampson, D.; Papadimitriou, M.; Kulatilake, A. E.

1970-01-01

A 5-megacycle Doppler flow meter, calibrated in-vitro, was found to give a linear response to blood flow in the ranges commonly encountered in haemodialysis. With this, blood flow through artificial kidneys could be measured simply and with a clinically acceptable error. The method is safe, as blood lines do not have to be punctured or disconnected and hence there is no risk of introducing infection. Besides its value as a research tool the flow meter is useful in evaluating new artificial kidneys. Suitably modified it could form the basis of an arterial flow alarm system. PMID:5416812

Flow Visualization and Laser Velocimetry for Wind Tunnels

NASA Technical Reports Server (NTRS)

Hunter, W. W., Jr. (Editor); Foughner, J. T., Jr. (Editor)

1982-01-01

The need for flow visualization and laser velocimetry were discussed. The purpose was threefold: (1) provide a state-of-the-art overview; (2) provide a forum for industry, universities, and government agencies to address problems in developing useful and productive flow visualization and laser velocimetry measurement techniques; and (3) provide discussion of recent developments and applications of flow visualization and laser velocimetry measurement techniques and instrumentation systems for wind tunnels including the 0.3-Meter Transonic Cryogenic Tunnel.

Design and Uncertainty Analysis for a PVTt Gas Flow Standard

PubMed Central

Wright, John D.; Johnson, Aaron N.; Moldover, Michael R.

2003-01-01

A new pressure, volume, temperature, and, time (PVTt) primary gas flow standard at the National Institute of Standards and Technology has an expanded uncertainty (k = 2) of between 0.02 % and 0.05 %. The standard spans the flow range of 1 L/min to 2000 L/min using two collection tanks and two diverter valve systems. The standard measures flow by collecting gas in a tank of known volume during a measured time interval. We describe the significant and novel features of the standard and analyze its uncertainty. The gas collection tanks have a small diameter and are immersed in a uniform, stable, thermostatted water bath. The collected gas achieves thermal equilibrium rapidly and the uncertainty of the average gas temperature is only 7 mK (22 × 10−6 T). A novel operating method leads to essentially zero mass change in and very low uncertainty contributions from the inventory volume. Gravimetric and volume expansion techniques were used to determine the tank and the inventory volumes. Gravimetric determinations of collection tank volume made with nitrogen and argon agree with a standard deviation of 16 × 10−6 VT. The largest source of uncertainty in the flow measurement is drift of the pressure sensor over time, which contributes relative standard uncertainty of 60 × 10−6 to the determinations of the volumes of the collection tanks and to the flow measurements. Throughout the range 3 L/min to 110 L/min, flows were measured independently using the 34 L and the 677 L collection systems, and the two systems agreed within a relative difference of 150 × 10−6. Double diversions were used to evaluate the 677 L system over a range of 300 L/min to 1600 L/min, and the relative differences between single and double diversions were less than 75 × 10−6. PMID:27413592

The Development of a Fiber Optic Raman Temperature Measurement System for Rocket Flows

NASA Technical Reports Server (NTRS)

Degroot, Wim A.

1992-01-01

A fiberoptic Raman diagnostic system for H2/O2 rocket flows is currently under development. This system is designed for measurement of temperature and major species concentration in the combustion chamber and part of the nozzle of a 100 Newton thrust rocket currently undergoing testing. This paper describes a measurement system based on the spontaneous Raman scattering phenomenon. An analysis of the principles behind the technique is given. Software is developed to measure temperature and major species concentrations by comparing theoretical Raman scattering spectra with experimentally obtained spectra. Equipment selection and experimental approach are summarized. This experimental program is part of a program, which is in progress, to evaluate Navier-Stokes based analyses for this class of rocket.

Vaporizing particle velocimeter

NASA Technical Reports Server (NTRS)

Weinstein, Leonard M. (Inventor)

1992-01-01

A velocimeter measures flow characteristics of a flow traveling through a chamber in a given direction. Tracer particles are entrained in the flow and a source of radiant energy produces an output stream directed transversely to the chamber, having a sufficient intensity to vaporize the particles as they pass through the output stream. Each of the vaporized particles explodes to produce a shock wave and a hot core, and a flow visualization system tracks the motion of the hot cores and shock waves to measure the velocity of each tracer particle and the temperature of the flow around the tracer.

Designing and Constructing an Optical Monitoring System of Blood Supply to Tissues under Pressure.

PubMed

Hadi, Akbari; Amin, Younessi Heravi Mohammad

2012-04-01

Reduced blood flow due to obstruction is in most cases a primary factor in pressure ulcer formation and creation of bedsores. The aim of this study is to design and manufacture a care system for tissue under pressure, based on variations in blood flow at different depths of tissue. In the manufacture of the system two infrared light transmitters and receivers were located between 5 and 10 mm depth to measure the flow of blood at different in the under- pressure heel tissue. In addition, blood flow was evaluated in an unloaded and loaded condition, with 30 mmHg and 60.0 mmHg. A total of 15 people participated with a mean age of 50. Of these 15; 9 (60%) were men and 6 (40%) were women. Primary measurement results showed different individual differences in variation of blood flow in the tissue. To study signal amplitude changes significantly influenced by external pressure the PPG, P-value was measured. It was noted that there were significant changes in PPG signal amplitude during loading both pressures of 30 and 60 mmHg. Further development of this system would be possible with the use of a more flexible probe and by using a stronger optical receiver and transmitter to access more depth.

Use of acoustic technology to define hydraulic characteristics of an estuary near the Mississippi Gulf Coast

USGS Publications Warehouse

Van Wilson, K.

2004-01-01

An Acoustic Doppler Current Profiler (ADCP) was used on the Jourdan River at Interstate Highway 10 near Kiln, Mississippi, in 1996 to measure three-dimensional velocity vectors and water depths and in 1998, in combination with a global positioning system, to define channel bathymetry in the vicinity of the bridge. During a 25-hour period on September 19-20, 1996, 117 consecutive measurements of stage and discharge were obtained throughout a complete tidal cycle. These measurements were obtained during the time of year when headwater flows were minimal, and, therefore, the tidal-affected flow conditions were noticeable. The stage ranged from only 0.7 to 2.8 ft above sea level, but discharge ranged from 3,980 ft3/s flowing upstream to 5,580 ft 3/s flowing downstream. The average discharge during the 25-hour period was only 80 ft3/s flowing downstream. By using the ADCP, full downstream flow, bi-directional flow, and full upstream flow conditions were identified. If conventional measurement techniques had been used, the bi-directional flow conditions could not have been detected since flow direction would have been based on what was seen at the water surface. These measurements were used to define the lower range of the stage-storage-volume relation inland of the highway. On June 10, 1998, the ADCP, in combination with a global positional system, was used to define channel bathymetry for the river reach from about 3,500 ft upstream to about 2,500 ft downstream of the bridge. The bathymetry was compared to past soundings obtained in the vicinity of the bridge; as much as 18 ft of total scour was indicated to have occurred at a bridge pier. Copyright ASCE 2004.

System-size independence of directed flow measured at the BNL relativistic heavy-ion collider.

PubMed

Abelev, B I; Aggarwal, M M; Ahammed, Z; Anderson, B D; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Baumgart, S; Beavis, D R; Bellwied, R; Benedosso, F; Betts, R R; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Biritz, B; Bland, L C; Bombara, M; Bonner, B E; Botje, M; Bouchet, J; Braidot, E; Brandin, A V; Bueltmann, S; Burton, T P; Bystersky, M; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Callner, J; Catu, O; Cebra, D; Cendejas, R; Cervantes, M C; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Cheng, J; Cherney, M; Chikanian, A; Choi, K E; Christie, W; Chung, S U; Clarke, R F; Codrington, M J M; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Dash, S; Daugherity, M; de Moura, M M; Dedovich, T G; Dephillips, M; Derevschikov, A A; Derradi de Souza, R; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Du, F; Dunlop, J C; Dutta Mazumdar, M R; Edwards, W R; Efimov, L G; Elhalhuli, E; Elnimr, M; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Eun, L; Fachini, P; Fatemi, R; Fedorisin, J; Feng, A; Filip, P; Finch, E; Fine, V; Fisyak, Y; Gagliardi, C A; Gaillard, L; Gangadharan, D R; Ganti, M S; Garcia-Solis, E; Ghazikhanian, V; Ghosh, P; Gorbunov, Y N; Gordon, A; Grebenyuk, O; Grosnick, D; Grube, B; Guertin, S M; Guimaraes, K S F F; Gupta, A; Gupta, N; Guryn, W; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Heppelmann, S; Hippolyte, B; Hirsch, A; Hoffman, A M; Hoffmann, G W; Hofman, D J; Hollis, R S; Huang, H Z; Hughes, E W; Humanic, T J; Igo, G; Iordanova, A; Jacobs, P; Jacobs, W W; Jakl, P; Jin, F; Jones, P G; Judd, E G; Kabana, S; Kajimoto, K; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Kettler, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Klein, S R; Knospe, A G; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kumar, A; Kumar, L; Kurnadi, P; Lamont, M A C; Landgraf, J M; Lange, S; Lapointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Levine, M J; Li, C; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, J; Liu, L; Ljubicic, T; Llope, W J; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Matis, H S; Matulenko, Yu A; McShane, T S; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mischke, A; Mitchell, J; Mohanty, B; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, C; Netrakanti, P K; Ng, M J; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okada, H; Okorokov, V; Olson, D; Pachr, M; Pal, S K; Panebratsev, Y; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Phatak, S C; Planinic, M; Pluta, J; Poljak, N; Porile, N; Poskanzer, A M; Potekhin, M; Potukuchi, B V K S; Prindle, D; Pruneau, C; Pruthi, N K; Putschke, J; Qattan, I A; Raniwala, R; Raniwala, S; Ray, R L; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Rykov, V; Sahoo, R; Sakrejda, I; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Schambach, J; Scharenberg, R P; Schmitz, N; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shi, S S; Shi, X-H; Sichtermann, E P; Simon, F; Singaraju, R N; Skoby, M J; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Staszak, D; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Subba, N L; Sumbera, M; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Symons, T J M; Szanto de Toledo, A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thein, D; Thomas, J H; Tian, J; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Tram, V N; Trattner, A L; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van der Kolk, N; van Leeuwen, M; Vander Molen, A M; Varma, R; Vasconcelos, G M S; Vasilevski, I M; Vasiliev, A N; Videbaek, F; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Wada, M; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, Q; Wang, X; Wang, X L; Wang, Y; Webb, J C; Westfall, G D; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, J; Wu, Y; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yang, Y Y; Yepes, P; Yoo, I-K; Yue, Q; Zawisza, M; Zbroszczyk, H; Zhan, W; Zhang, H; Zhang, S; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zhou, J; Zoulkarneev, R; Zoulkarneeva, Y; Zuo, J X

2008-12-19

We measure directed flow (v_{1}) for charged particles in Au+Au and Cu+Cu collisions at sqrt[s_{NN}]=200 and 62.4 GeV, as a function of pseudorapidity (eta), transverse momentum (p_{t}), and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragmentation concept to v_{1} in different collision systems, and investigate possible explanations for the observed sign change in v_{1}(p_{t}).

μ-PIV measurements of the ensemble flow fields surrounding a migrating semi-infinite bubble.

PubMed

Yamaguchi, Eiichiro; Smith, Bradford J; Gaver, Donald P

2009-08-01

Microscale particle image velocimetry (μ-PIV) measurements of ensemble flow fields surrounding a steadily-migrating semi-infinite bubble through the novel adaptation of a computer controlled linear motor flow control system. The system was programmed to generate a square wave velocity input in order to produce accurate constant bubble propagation repeatedly and effectively through a fused glass capillary tube. We present a novel technique for re-positioning of the coordinate axis to the bubble tip frame of reference in each instantaneous field through the analysis of the sudden change of standard deviation of centerline velocity profiles across the bubble interface. Ensemble averages were then computed in this bubble tip frame of reference. Combined fluid systems of water/air, glycerol/air, and glycerol/Si-oil were used to investigate flows comparable to computational simulations described in Smith and Gaver (2008) and to past experimental observations of interfacial shape. Fluorescent particle images were also analyzed to measure the residual film thickness trailing behind the bubble. The flow fields and film thickness agree very well with the computational simulations as well as existing experimental and analytical results. Particle accumulation and migration associated with the flow patterns near the bubble tip after long experimental durations are discussed as potential sources of error in the experimental method.

Dynamic measurements in non-uniform flows

NASA Astrophysics Data System (ADS)

Ershov, A. P.

2017-12-01

The response of gauges registering the flow velocity and pressure in highly non-uniform media (for example, a powder under shock compression or powdered low-density explosive) is simulated. The modeling employs an acoustic approach. Against the average level of the signal, the fluctuations generated by the heterogeneity of the medium are observed which may distort the results completely. For reliable measurements, gauges larger than the characteristic scale of the medium non-uniformity are required. Under this condition, electromagnetic flow measurements and the velocity interferometer system for any reflector (VISAR) produce quite similar flow velocity profiles with small level of noise.

Dynamic measurements in non-uniform flows

NASA Astrophysics Data System (ADS)

Ershov, A. P.

2018-07-01

The response of gauges registering the flow velocity and pressure in highly non-uniform media (for example, a powder under shock compression or powdered low-density explosive) is simulated. The modeling employs an acoustic approach. Against the average level of the signal, the fluctuations generated by the heterogeneity of the medium are observed which may distort the results completely. For reliable measurements, gauges larger than the characteristic scale of the medium non-uniformity are required. Under this condition, electromagnetic flow measurements and the velocity interferometer system for any reflector (VISAR) produce quite similar flow velocity profiles with small level of noise.

A Multi-Beam Interferometer and Its Use as a Screening System in Gynecologic Cytology

NASA Astrophysics Data System (ADS)

Fujii, Ken-ichi; Suzuki, Norihito

1982-11-01

Clumps of cells remaining after the cell separation process present the greatest obstacle to the development of an automated screening system using flow cytofluorometry. There are two main problems caused by such clumps of cells. One occurs in the flow system, when the clumps block the nozzles, while the other occurs in the measuring system, when the clumps give a false fluorescence intensity. The former problem can be solved by designing the flow system appropriately, and the latter can be obviated by using a multi-beam interferometer.

An airborne system for vortex flow visualization on the F-18 high-alpha research vehicle

NASA Technical Reports Server (NTRS)

Curry, Robert E.; Richwine, David M.

1988-01-01

A flow visualization system for the F-18 high-alpha research vehicle is described which allows direct observation of the separated vortex flows over a wide range of flight conditions. The system consists of a smoke generator system, on-board photographic and video systems, and instrumentation. In the present concept, smoke is entrained into the low-pressure vortex core, and vortice breakdown is indicated by a rapid diffusion of the smoke. The resulting pattern is observed using photographic and video images and is correlated with measured flight conditions.

EDITORIAL: Measurement techniques for multiphase flows Measurement techniques for multiphase flows

NASA Astrophysics Data System (ADS)

Okamoto, Koji; Murai, Yuichi

2009-11-01

Research on multiphase flows is very important for industrial applications, including power stations, vehicles, engines, food processing and so on. Multiphase flows originally have nonlinear features because of multiphase systems. The interaction between the phases plays a very interesting role in the flows. The nonlinear interaction causes the multiphase flows to be very complicated. Therefore techniques for measuring multiphase flows are very useful in helping to understand the nonlinear phenomena. The state-of-the-art measurement techniques were presented and discussed at the sixth International Symposium on Measurement Techniques for Multiphase Flows (ISMTMF2008) held in Okinawa, Japan, on 15-17 December 2008. This special feature of Measurement Science and Technology includes selected papers from ISMTMF2008. Okinawa has a long history as the Ryukyus Kingdom. China, Japan and many western Pacific countries have had cultural and economic exchanges through Okinawa for over 1000 years. Much technical and scientific information was exchanged at the symposium in Okinawa. The proceedings of ISMTMF2008 apart from these special featured papers were published in Journal of Physics: Conference Series vol. 147 (2009). We would like to express special thanks to all the contributors to the symposium and this special feature. This special feature will be a milestone in measurement techniques for multiphase flows.

Using the VentCam and Optical Plume Velocimetry to Measure High-Temperature Hydrothermal Fluid Flow Rates in the ASHES Vent Field on Axial Volcano

NASA Astrophysics Data System (ADS)

Crone, T. J.; Mittelstaedt, E. L.; Fornari, D. J.

2014-12-01

Fluid flow rates through high-temperature mid-ocean ridge hydrothermal vents are likely quite sensitive to poroelastic forcing mechanisms such as tidal loading and tectonic activity. Because poroelastic deformation and flow perturbations are estimated to extend to considerable depths within young oceanic crust, observations of flow rate changes at seafloor vents have the potential to provide constraints on the flow geometry and permeability structure of the underlying hydrothermal systems, as well as the quantities of heat and chemicals they exchange with overlying ocean, and the potential biological productivity of ecosystems they host. To help provide flow rate measurements in these challenging environments, we have developed two new optical flow oriented technologies. The first is a new form of Optical Plume Velocimetry (OPV) which relies on single-frame temporal cross-correlation to obtain time-averaged image velocity fields from short video sequences. The second is the VentCam, a deep sea camera system that can collect high-frame-rate video sequences at focused hydrothermal vents suitable for analysis with OPV. During the July 2014 R/V Atlantis/Alvin expedition to Axial Seamount, we deployed the VentCam at the ~300C Phoenix vent within the ASHES vent field and positioned it with DSRV Alvin. We collected 24 seconds of video at 50 frames per second every half-hour for approximately 10 days beginning July 22nd. We are currently applying single-frame lag OPV to these videos to estimate relative and absolute fluid flow rates through this vent. To explore the relationship between focused and diffuse venting, we deployed a second optical flow camera, the Diffuse Effluent Measurement System (DEMS), adjacent to this vent at a fracture within the lava carapace where low-T (~30C) fluids were exiting. This system collected video sequences and diffuse flow measurements at overlapping time intervals. Here we present the preliminary results of our work with VentCam and OPV, and comparisons with results from the DEMS camera.

New devices for flow measurements: Hot film and burial wire sensors, infrared imagery, liquid crystal, and piezo-electric model

NASA Technical Reports Server (NTRS)

Mcree, Griffith J., Jr.; Roberts, A. Sidney, Jr.

1991-01-01

An experimental program aimed at identifying areas in low speed aerodynamic research where infrared imaging systems can make significant contributions is discussed. Implementing a new technique, a long electrically heated wire was placed across a laminar flow. By measuring the temperature distribution along the wire with the IR imaging camera, the flow behavior was identified.

Operating manual for the digital data-collection system for flow-control structures

USGS Publications Warehouse

Rorabaugh, J.I.; Rapp, W.L.

1986-01-01

This manual was written to help the user operate and maintain the digital data collection system for flow control structures. The system is used to measure daily discharge through river control dams. These dams commonly have tainter gates which are raised and lowered to keep the upper pool level relatively constant as the river flow changes. In order to measure the flow through such a structure, the positions of the tainter gates and the headwater and tailwater elevations must be known. From these data, the flow through the structure can be calculated. A typical digital data collection system is shown. Digitizing devices are mounted on the hoisting mechanism of each gate, as well as at the headwater and tailwater gages. Data from these digitizers are then routed by electrical cables to a central console where they are displayed and recorded on paper tape. If the dam has locks, a pressure-sensitive switch located in the lock activates a counter in the console which keeps track of the number of times the lock is drained and filled. (USGS)

Ion flow measurements during the rotating kink behavior of the central column in the HIST device

NASA Astrophysics Data System (ADS)

Yamada, S.; Yoshikawa, T.; Hashimoto, S.; Nishioka, T.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2007-11-01

Plasma flow is essentially driven in self-organization and magnetic reconnection process of compact spherical torus (ST) and spheromak in the helicity-driven systems. For example, when reversing the external toroidal field of ST, the direction not only of the plasma current but also of the toroidal ion flow is self-reversed during the formation of the flipped ST relaxed states. Mach probe measurement shows that the velocity of the ion flow reversed after the flip increases to about 20 km/s. We have been newly developing an ion Doppler spectrometer (IDS) system using a compact 16 or 64 channel photomultiplier tube (PMT) in order to measure the spatial profile of ion temperature and rotation velocity in the HIST device. The IDS system consists of a light collection system including optical fibers, 1 m-spectrometer and the PMT detector. The optical fibers covered with glass tubes are inserted into the plasma. The glass tubes can be rotated in the poloidal and the toroidal directions. The new IDS system will be applied to observations of ion temperature and plasma rotation in the flipped ST formation and in the MHD control of kinking behaviors of the central column by using the rotating magnetic field (RMF). Preliminary IDS results will be compared to those from Mach probe measurements in space.

Novel monorail infusion catheter for volumetric coronary blood flow measurement in humans: in vitro validation.

PubMed

van 't Veer, Marcel; Adjedj, Julien; Wijnbergen, Inge; Tóth, Gabor G; Rutten, Marcel C M; Barbato, Emanuele; van Nunen, Lokien X; Pijls, Nico H J; De Bruyne, Bernard

2016-08-20

The aim of this study is to validate a novel monorail infusion catheter for thermodilution-based quantitative coronary flow measurements. Based on the principles of thermodilution, volumetric coronary flow can be determined from the flow rate of a continuous saline infusion, the temperature of saline when it enters the coronary artery, and the temperature of the blood mixed with the saline in the distal part of the coronary artery. In an in vitro set-up of the systemic and coronary circulation at body temperature, coronary flow values were varied from 50-300 ml/min in steps of 50 ml/min. At each coronary flow value, thermodilution-based measurements were performed at infusion rates of 15, 20, and 30 ml/min. Temperatures and pressures were simultaneously measured with a pressure/temperature sensor-tipped guidewire. Agreement of the calculated flow and the measured flow as well as repeatability were assessed. A total of five catheters were tested, with a total of 180 measurements. A strong correlation (ρ=0.976, p<0.0001) and a difference of -6.5±15.5 ml/min were found between measured and calculated flow. The difference between two repeated measures was 0.2%±8.0%. This novel infusion catheter used in combination with a pressure/temperature sensor-tipped guidewire allows accurate and repeatable absolute coronary flow measurements. This opens a window to a better understanding of the coronary microcirculation.

Design of Flow Systems for Improved Networking and Reduced Noise in Biomolecular Signal Processing in Biocomputing and Biosensing Applications

PubMed Central

Verma, Arjun; Fratto, Brian E.; Privman, Vladimir; Katz, Evgeny

2016-01-01

We consider flow systems that have been utilized for small-scale biomolecular computing and digital signal processing in binary-operating biosensors. Signal measurement is optimized by designing a flow-reversal cuvette and analyzing the experimental data to theoretically extract the pulse shape, as well as reveal the level of noise it possesses. Noise reduction is then carried out numerically. We conclude that this can be accomplished physically via the addition of properly designed well-mixing flow-reversal cell(s) as an integral part of the flow system. This approach should enable improved networking capabilities and potentially not only digital but analog signal-processing in such systems. Possible applications in complex biocomputing networks and various sense-and-act systems are discussed. PMID:27399702

Particle velocity measurements with macroscopic fluorescence imaging in lymph tissue mimicking microfluidic phantoms

NASA Astrophysics Data System (ADS)

Hennessy, Ricky; Koo, Chiwan; Ton, Phuc; Han, Arum; Righetti, Raffaella; Maitland, Kristen C.

2011-03-01

Ultrasound poroelastography can quantify structural and mechanical properties of tissues such as stiffness, compressibility, and fluid flow rate. This novel ultrasound technique is being explored to detect tissue changes associated with lymphatic disease. We have constructed a macroscopic fluorescence imaging system to validate ultrasonic fluid flow measurements and to provide high resolution imaging of microfluidic phantoms. The optical imaging system is composed of a white light source, excitation and emission filters, and a camera with a zoom lens. The field of view can be adjusted from 100 mm x 75 mm to 10 mm x 7.5 mm. The microfluidic device is made of polydimethylsiloxane (PDMS) and has 9 channels, each 40 μm deep with widths ranging from 30 μm to 200 μm. A syringe pump was used to propel water containing 15 μm diameter fluorescent microspheres through the microchannels, with flow rates ranging from 0.5 μl/min to 10 μl/min. Video was captured at a rate of 25 frames/sec. The velocity of the microspheres in the microchannels was calculated using an algorithm that tracked the movement of the fluorescent microspheres. The imaging system was able to measure particle velocities ranging from 0.2 mm/sec to 10 mm/sec. The range of flow velocities of interest in lymph vessels is between 1 mm/sec to 10 mm/sec; therefore our imaging system is sufficient to measure particle velocity in phantoms modeling lymphatic flow.

Advanced nozzle and engine components test facility

NASA Technical Reports Server (NTRS)

Beltran, Luis R.; Delroso, Richard L.; Delrosario, Ruben

1992-01-01

A test facility for conducting scaled advanced nozzle and engine component research is described. The CE-22 test facility, located in the Engine Research Building of the NASA Lewis Research Center, contains many systems for the economical testing of advanced scale-model nozzles and engine components. The combustion air and altitude exhaust systems are described. Combustion air can be supplied to a model up to 40 psig for primary air flow, and 40, 125, and 450 psig for secondary air flow. Altitude exhaust can be simulated up to 48,000 ft, or the exhaust can be atmospheric. Descriptions of the multiaxis thrust stand, a color schlieren flow visualization system used for qualitative flow analysis, a labyrinth flow measurement system, a data acquisition system, and auxiliary systems are discussed. Model recommended design information and temperature and pressure instrumentation recommendations are included.

Streamflow measurements, basin characteristics, and streamflow statistics for low-flow partial-record stations operated in Massachusetts from 1989 through 1996

USGS Publications Warehouse

Ries, Kernell G.

1999-01-01

A network of 148 low-flow partial-record stations was operated on streams in Massachusetts during the summers of 1989 through 1996. Streamflow measurements (including historical measurements), measured basin characteristics, and estimated streamflow statistics are provided in the report for each low-flow partial-record station. Also included for each station are location information, streamflow-gaging stations for which flows were correlated to those at the low-flowpartial-record station, years of operation, and remarks indicating human influences of stream-flowsat the station. Three or four streamflow measurements were made each year for three years during times of low flow to obtain nine or ten measurements for each station. Measured flows at the low-flow partial-record stations were correlated with same-day mean flows at a nearby gaging station to estimate streamflow statistics for the low-flow partial-record stations. The estimated streamflow statistics include the 99-, 98-, 97-, 95-, 93-, 90-, 85-, 80-, 75-, 70-, 65-, 60-, 55-, and 50-percent duration flows; the 7-day, 10- and 2-year low flows; and the August median flow. Characteristics of the drainage basins for the stations that theoretically relate to the response of the station to climatic variations were measured from digital map data by use of an automated geographic information system procedure. Basin characteristics measured include drainage area; total stream length; mean basin slope; area of surficial stratified drift; area of wetlands; area of water bodies; and mean, maximum, and minimum basin elevation.Station descriptions and calculated streamflow statistics are also included in the report for the 50 continuous gaging stations used in correlations with the low-flow partial-record stations.

Method and apparatus to measure vapor pressure in a flow system

DOEpatents

Grossman, Mark W.; Biblarz, Oscar

1991-01-01

The present invention is directed to a method for determining, by a condensation method, the vapor pressure of a material with a known vapor pressure versus temperature characteristic, in a flow system particularly in a mercury isotope enrichment process.

Assessment of the urban water system with an open, reproducible process applied to Chicago

EPA Science Inventory

Urban water systems convey complex environmental and man-made flows. The relationships among water flows and networked storages remains difficult to comprehensively evaluate. Such evaluation is important, however, as interventions are designed (e.g, conservation measures, green...

Spectral measurement of nonequilibrium arc-jet free-stream flow

NASA Technical Reports Server (NTRS)

Gopaul, Nigel K. J. M.

1993-01-01

Spectra of radiation emitted by the free-stream flow of air in an arcjet wind tunnel at NASA-Ames Research Center were studied experimentally. The arcjet produces a high energy gaseous flow that is expanded to low density and low temperature to produce high velocities in the free-stream for simulating atmospheric entry conditions. The gamma and the delta band systems of nitric oxide emitted by the free stream were measured in the second order. The NO-beta band system, which is in the same spectral region as the NO-gamma and NO-delta band systems, was not present in the data. Only transitions from the lowest vibrational level of the upper state of both the NO-gamma and NO-delta band systems were observed. The rotational temperature determined from these band systems was 660 +/- 50 deg K. The maximum possible vibrational temperature was determined to be less than 850 +/- 50 deg K. The electronic temperature determined from the ratio of the intensities of the NO-gamma and NO-delta band systems was 7560 +/- 340 K. The results indicate that the arcjet free-stream flow is in thermal nonequilibrium.

Controlling Gas-Flow Mass Ratios

NASA Technical Reports Server (NTRS)

Morris, Brian G.

1990-01-01

Proposed system automatically controls proportions of gases flowing in supply lines. Conceived for control of oxidizer-to-fuel ratio in new gaseous-propellant rocket engines. Gas-flow control system measures temperatures and pressures at various points. From data, calculates control voltages for electronic pressure regulators for oxygen and hydrogen. System includes commercially available components. Applicable to control of mass ratios in such gaseous industrial processes as chemical-vapor depostion of semiconductor materials and in automotive engines operating on compressed natural gas.

Characterization of a Combined CARS and Interferometric Rayleigh Scattering System

NASA Technical Reports Server (NTRS)

Tedder, Sarah A.; Bivolaru, Daniel; Danehy, Paul M.; Weikl, M. C.; Beyrau, F.; Seeger, T.; Cutler, Andrew D.

2007-01-01

This paper describes the characterization of a combined Coherent anti-Stokes Raman Spectroscopy and Interferometric Rayleigh Scattering (CARS-IRS) system by reporting the accuracy and precision of the measurements of temperature, species mole fraction of N2, O2, and H2, and two-components of velocity. A near-adiabatic H2-air Hencken burner flame was used to provide known properties for measurements made with the system. The measurement system is also demonstrated in a small-scale Mach 1.6 H2-air combustion-heated supersonic jet with a co-flow of H2. The system is found to have a precision that is sufficient to resolve fluctuations of flow properties in the mixing layer of the jet.

Scattering matrix elements of biological particles measured in a flow through system: theory and practice.

PubMed

Sloot, P M; Hoekstra, A G; van der Liet, H; Figdor, C G

1989-05-15

Light scattering techniques (including depolarization experiments) applied to biological cells provide a fast nondestructive probe that is very sensitive to small morphological differences. Until now quantitative measurement of these scatter phenomena were only described for particles in suspension. In this paper we discuss the symmetry conditions applicable to the scattering matrices of monodisperse biological cells in a flow cytometer and provide evidence that quantitative measurement of the elements of these scattering matrices is possible in flow through systems. Two fundamental extensions to the theoretical description of conventional scattering experiments are introduced: large cone integration of scattering signals and simultaneous implementation of the localization principle to account for scattering by a sharply focused laser beam. In addition, a specific calibration technique is proposed to account for depolarization effects of the highly specialized optics applied in flow through equipment.

Experiments in a flighted conveyor comparing shear rates in compressed versus free surface flows

NASA Astrophysics Data System (ADS)

Pohlman, Nicholas; Higgins, Hannah; Krupiarz, Kamila; O'Connor, Ryan

2017-11-01

Uniformity of granular flow rate is critical in industry. Experiments in a flighted conveyor system aim to fill a gap in knowledge of achieving steady mass flow rate by correlating velocity profile data with mass flow rate measurements. High speed images were collected for uniformly-shaped particles in a bottom-driven flow conveyor belt system from which the velocity profiles can be generated. The correlation of mass flow rates from the velocity profiles to the time-dependent mass measurements will determine energy dissipation rates as a function of operating conditions. The velocity profiles as a function of the size of the particles, speed of the belt, and outlet size, will be compared to shear rate relationships found in past experiments that focused on gravity-driven systems. The dimension of the linear shear and type of decaying transition to the stationary bed may appear different due to the compression versus dilation space in open flows. The application of this research can serve to validate simulations in discrete element modeling and physically demonstrate a process that can be further developed and customized for industry applications, such as feeding a biomass conversion reactor. Sponsored by NIU's Office of Student Engagement and Experiential Learning.

Prediction of induction time for methane hydrate formation in the presence or absence of THF in flow loop system by Natarajan model

NASA Astrophysics Data System (ADS)

Talaghat, Mohammad Reza; Jokar, Seyyed Mohammad

2018-03-01

The induction time is a time interval to detect the initial hydrate formation, which is counted from the moment when the stirrer is turned on until the first detection of hydrate formation. The main objective of the present work is to predict and measure the induction time of methane hydrate formation in the presence or absence of tetrahydrofuran (THF) as promoter in the flow loop system. A laboratory flow mini-loop apparatus was set up to measure the induction time of methane hydrate formation. The induction time is predicted using developed Kashchiev and Firoozabadi model and modified model of Natarajan for a flow loop system. Furthermore, the effects of volumetric flow rate of the fluid on the induction time were investigated. The results of the models were compared with experimental data. They show that the induction time of hydrate formation in the presence of THF is very short at high pressure and high volumetric flow rate of the fluid. It decreases with increasing pressure and liquid volumetric flow rate. It is also shown that the modified Natarajan model is more accurate than the Kashchiev and Firoozabadi ones in prediction of the induction time.

Development of a Deep-Penetrating, Compact Geothermal Heat Flow System for Robotic Lunar Geophysical Missions

NASA Technical Reports Server (NTRS)

Nagihara, Seiichi; Zacny, Kris; Hedlund, Magnus; Taylor, Patrick T.

2012-01-01

Geothermal heat flow measurements are a high priority for the future lunar geophysical network missions recommended by the latest Decadal Survey of the National Academy. Geothermal heat flow is obtained as a product of two separate measurements of geothermal gradient and thermal conductivity of the regolith/soil interval penetrated by the instrument. The Apollo 15 and 17 astronauts deployed their heat flow probes down to 1.4-m and 2.3-m depths, respectively, using a rotary-percussive drill. However, recent studies show that the heat flow instrument for a lunar mission should be capable of excavating a 3-m deep hole to avoid the effect of potential long-term changes of the surface thermal environment. For a future robotic geophysical mission, a system that utilizes a rotary/percussive drill would far exceed the limited payload and power capacities of the lander/rover. Therefore, we are currently developing a more compact heat flow system that is capable of 3-m penetration. Because the grains of lunar regolith are cohesive and densely packed, the previously proposed lightweight, internal hammering systems (the so-called moles ) are not likely to achieve the desired deep penetration. The excavation system for our new heat flow instrumentation utilizes a stem which winds out of a pneumatically driven reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab tests have demonstrated that this proboscis system has much greater excavation capability than a mole-based heat flow system, while it weighs about the same. Thermal sensors are attached along the stem and at the tip of the penetrating cone. Thermal conductivity is measured at the cone tip with a short (1- to 1.5-cm long) needle sensor containing a resistance temperature detector (RTD) and a heater wire. When it is inserted into the soil, the heater is activated. Thermal conductivity of the soil is obtained from the rate of temperature increase during the heating. By stopping during the excavation, it is possible to measure thermal conductivities at different depths. The gas jets are turned off when the penetrating cone reaches the target depth. Then, the stem pushes the needle sensor into the undisturbed soil at the bottom of the hole and carries out a thermal conductivity measurement. When the measurement is complete, the system resumes excavation. RTDs, placed along the stem at short (approx 30 cm) intervals, will monitor long-term temperature stability of the subsurface. Temperature in the shallow subsurface would fluctuate with the diurnal, annual, and precession cycles of the Moon. These thermal waves penetrate to different depths into the regolith. Longterm monitoring of the subsurface temperature would allow us to accurately delineate these cyclic signals and separate them from the signal associated with the outward flow of the Moon s endogenic heat. Further, temperature toward bottom of the 3-m hole should be fairly stable after the heat generated during the excavation dissipates into the surrounding soil. The geothermal gradient may be determined reliably from temperature measurements at the RTDs near the bottom. In order to minimize the heat conduction along the stem from affecting the geothermal gradient measurements, we plan to use low-conductive materials for the stem and develop a mechanism to achieve close coupling between the RTDs and the wall of the excavated hole.

Optical measurement of high-temperature melt flow rate.

PubMed

Bizjan, Benjamin; Širok, Brane; Chen, Jinpeng

2018-05-20

This paper presents an optical method and system for contactless measurement of the mass flow rate of melts by digital cameras. The proposed method is based on reconstruction of melt stream geometry and flow velocity calculation by cross correlation, and is very cost-effective due its modest hardware requirements. Using a laboratory test rig with a small inductive melting pot and reference mass flow rate measurement by weighing, the proposed method was demonstrated to have an excellent dynamic response (0.1 s order of magnitude) while producing deviations from the reference of about 5% in the steady-state flow regime. Similar results were obtained in an industrial stone wool production line for two repeated measurements. Our method was tested in a wide range of melt flow rates (0.05-1.2 kg/s) and did not require very fast cameras (120 frames per second would be sufficient for most industrial applications).

Experimental Evaluation of an Isolated Synthetic Jet IN Crossflow

NASA Technical Reports Server (NTRS)

Schaeffler, Norman W.; Jenkins, Luther N.; Hepner, Timothy E.

2007-01-01

The second case for this workshop builds upon the isolated synthetic jet of Case 1 by adding a crossflow, with no streamwise pressure gradient, for the developing jet to interact with. Formally, Case 2 examines the interaction of a single, isolated, synthetic jet and a fully turbulent zero-pressure gradient boundary layer. The resulting flow has many of the characteristics that need to be modeled with fidelity if the results of the calculations are to serve as the basis for research and design with active flow control devices. These include the turbulence in the boundary layer, the time-evolution of the large vortical structure emanating from the jet orifice and its subsequent interaction with and distortion by the boundary layer turbulence, and the effect of the suction cycle on the boundary layer flow. In a synthetic jet, the flow through the orifice and out into the outer flowfield alternates between an exhaust and a suction cycle, driven by the contraction and expansion of a cavity internal to the actuator. In the present experiment, the volume changes in the internal cavity are accomplished by replacing one of the rigid walls of the cavity, the wall opposite the orifice exit, with a deformable wall. This flexible wall is driven by a bottom-mounted moveable piston. The piston is driven electro-mechanically. The synthetic jet issues into the external flow through a circular orifice. In the present experiment, this orifice has a diameter of 0.250 inches (6.35 mm). The flow is conceptually similar to that documented in Schaeffler [1]. To document the flow, several measurement techniques were utilized. The upstream boundary conditions (in-flow conditions), and several key phase-averaged velocity profiles were measured with a 3-component laser-Doppler velocimetry system. Phase-averaged velocity field measurements were made with both stereo digital particle image velocimetry and 2-D digital particle image velocimetry as the primary measurement system. Surface pressure measurements were made utilizing an electronically scanned pressure system.

Advanced optical measuring systems for measuring the properties of fluids and structures

NASA Technical Reports Server (NTRS)

Decker, A. J.

1986-01-01

Four advanced optical models are reviewed for the measurement of visualization of flow and structural properties. Double-exposure, diffuse-illumination, holographic interferometry can be used for three-dimensional flow visualization. When this method is combined with optical heterodyning, precise measurements of structural displacements or fluid density are possible. Time-average holography is well known as a method for displaying vibrational mode shapes, but it also can be used for flow visualization and flow measurements. Deflectometry is used to measure or visualize the deflection of light rays from collimation. Said deflection occurs because of refraction in a fluid or because of reflection from a tilted surface. The moire technique for deflectometry, when combined with optical heterodyning, permits very precise measurements of these quantities. The rainbow schlieren method of deflectometry allows varying deflection angles to be encoded with colors for visualization.

Rayleigh Scattering Diagnostic for Measurement of Temperature and Velocity in Harsh Environments

NASA Technical Reports Server (NTRS)

Seasholtz, Richard G.; Greer, Lawrence C., III

1998-01-01

A molecular Rayleigh scattering system for temperature and velocity measurements in unseeded flows is described. The system is capable of making measurements in the harsh environments commonly found in aerospace test facilities, which may have high acoustic sound levels, varying temperatures, and high vibration levels. Light from an argon-ion laser is transmitted via an optical fiber to a remote location where two flow experiments were located. One was a subsonic free air jet; the second was a low-speed heated airjet. Rayleigh scattered light from the probe volume was transmitted through another optical fiber from the remote location to a controlled environment where a Fabry-Perot interferometer and cooled CCD camera were used to analyze the Rayleigh scattered light. Good agreement between the measured velocity and the velocity calculated from isentropic flow relations was demonstrated (less than 5 m/sec). The temperature measurements, however, exhibited systematic errors on the order of 10-15%.

Effect of Transpiration Injection on Skin Friction in an Internal Supersonic Flow

NASA Technical Reports Server (NTRS)

Castiglone, L. A.; Northam, G. B.; Baker, N. R.; Roe, L. A.

1996-01-01

An experimental program was conducted at NASA Langley Research Center that included development and evaluation of an operational facility for wall drag measurement of potential scramjet fuel injection or wall cooling configurations. The facility consisted of a supersonic tunnel, with one wall composed of a series of interchangeable aluminum plates attached to an air bearing suspension system. The system was equipped with load cells that measured drag forces of 115 psia (793 kPa). This flow field contained a train of weak, unsteady, reflecting shock waves that were produced in the Mach 2 nozzle flows, the effect of reflecting shocks (which are to be expected in scramjet combustors) in internal flows has not previously been documented.

Design and nonlinear modeling of a sensitive sensor for the measurement of flow in mice.

PubMed

Bou Jawde, Samer; Smith, Bradford J; Sonnenberg, Adam; Bates, Jason H T; Suki, Bela

2018-06-07

While many studies rely on flow and pressure measurements in small animal models of respiratory disease, such measurements can however be inaccurate and difficult to obtain. Thus, the goal of this study was to design and implement an easy to manufacture and accurate sensor capable of monitoring flow. We designed and 3-D printed a flowmeter and utilized parametric (resistance and inertance) and nonparametric (polynomial and Volterra series) system identification to characterize the device. The sensor was tested in a closed system for apparent flow using the common mode rejection ratio (CMRR). The sensor properly measured tidal volumes and respiratory rates in spontaneously breathing mice. The device was used to evaluate a ventilator's ability to deliver a prescribed volume before and after lung injury. The parametric and polynomial models provided a reasonable prediction of the independently measured flow (Coefficient of determination (Cv)=0.9591 and 0.9147 respectively), but the Volterra series of the 1st, 2nd, and 3rd order with a memory of six time points provided better fits (Cv=0.9775, 0.9787, and 0.9954, respectively). At and below the mouse breathing frequency (1-5 Hz), CMRR was higher than 40 dB. Following lung injury, the sensor revealed a significant drop in delivered tidal volume. We demonstrate that the application of nonparametric nonlinear Volterra series modeling in combination with 3-D printing technology allows the inexpensive and rapid fabrication of an accurate flow sensor for continuously measuring small flows in various physiological conditions. © 2018 Institute of Physics and Engineering in Medicine.

Hemodynamic measurements in rat brain and human muscle using diffuse near-infrared absorption and correlation spectroscopies

NASA Astrophysics Data System (ADS)

Yu, Guoqiang; Durduran, Turgut; Furuya, D.; Lech, G.; Zhou, Chao; Chance, Britten; Greenberg, J. H.; Yodh, Arjun G.

2003-07-01

Measurement of concentration, oxygenation, and flow characteristics of blood cells can reveal information about tissue metabolism and functional heterogeneity. An improved multifunctional hybrid system has been built on the basis of our previous hybrid instrument that combines two near-infrared diffuse optical techniques to simultaneously monitor the changes of blood flow, total hemoglobin concentration (THC) and blood oxygen saturation (StO2). Diffuse correlation spectroscopy (DCS) monitors blood flow (BF) by measuring the optical phase shifts caused by moving blood cells, while diffuse photon density wave spectroscopy (DPDW) measures tissue absorption and scattering. Higher spatial resolution, higher data acquisition rate and higher dynamic range of the improved system allow us to monitor rapid hemodynamic changes in rat brain and human muscles. We have designed two probes with different source-detector pairs and different separations for the two types of experiments. A unique non-contact probe mounted on the back of a camera, which allows continuous measurements without altering the blood flow, was employed to in vivo monitor the metabolic responses in rat brain during KCl induced cortical spreading depression (CSD). A contact probe was used to measure changes of blood flow and oxygenation in human muscle during and after cuff occlusion or exercise, where the non-contact probe is not appropriate for monitoring the moving target. The experimental results indicate that our multifunctional hybrid system is capable of in vivo and non-invasive monitoring of the hemodynamic changes in different tissues (smaller tissues in rat brain, larger tissues in human muscle) under different conditions (static versus moving). The time series images of flow during CSD obtained by our technique revealed spatial and temporal hemodynamic changes in rat brain. Two to three fold longer recovery times of flow and oxygenation after cuff occlusion or exercise from calf flexors in a patient with peripheral vascular disease (PVD) were found.

Effects of free convection and friction on heat-pulse flowmeter measurement

NASA Astrophysics Data System (ADS)

Lee, Tsai-Ping; Chia, Yeeping; Chen, Jiun-Szu; Chen, Hongey; Liu, Chen-Wuing

2012-03-01

SummaryHeat-pulse flowmeter can be used to measure low flow velocities in a borehole; however, bias in the results due to measurement error is often encountered. A carefully designed water circulation system was established in the laboratory to evaluate the accuracy and precision of flow velocity measured by heat-pulse flowmeter in various conditions. Test results indicated that the coefficient of variation for repeated measurements, ranging from 0.4% to 5.8%, tends to increase with flow velocity. The measurement error increases from 4.6% to 94.4% as the average flow velocity decreases from 1.37 cm/s to 0.18 cm/s. We found that the error resulted primarily from free convection and frictional loss. Free convection plays an important role in heat transport at low flow velocities. Frictional effect varies with the position of measurement and geometric shape of the inlet and flow-through cell of the flowmeter. Based on the laboratory test data, a calibration equation for the measured flow velocity was derived by the least-squares regression analysis. When the flowmeter is used with a diverter, the range of measured flow velocity can be extended, but the measurement error and the coefficient of variation due to friction increase significantly. At higher velocities under turbulent flow conditions, the measurement error is greater than 100%. Our laboratory experimental results suggested that, to avoid a large error, the heat-pulse flowmeter measurement is better conducted in laminar flow and the effect of free convection should be eliminated at any flow velocities. Field measurement of the vertical flow velocity using the heat-pulse flowmeter was tested in a monitoring well. The calibration of measured velocities not only improved the contrast in hydraulic conductivity between permeable and less permeable layers, but also corrected the inconsistency between the pumping rate and the measured flow rate. We identified two highly permeable sections where the horizontal hydraulic conductivity is 3.7-6.4 times of the equivalent hydraulic conductivity obtained from the pumping test. The field test results indicated that, with a proper calibration, the flowmeter measurement is capable of characterizing the vertical distribution of preferential flow or hydraulic conductivity.

Laser transit anemometer measurements on a slender cone in the Langley unitary plan wind tunnel

NASA Technical Reports Server (NTRS)

Humphreys, William M., Jr.; Hunter, William W., Jr.; Covell, Peter F.; Nichols, Cecil E., Jr.

1990-01-01

A laser transit anemometer (LTA) system was used to probe the boundary layer on a slender (5 degree half angle) cone model in the Langley unitary plan wind tunnel. The anemometer system utilized a pair of laser beams with a diameter of 40 micrometers spaced 1230 micrometers apart to measure the transit times of ensembles of seeding particles using a cross-correlation technique. From these measurements, boundary layer profiles around the model were constructed and compared with CFD calculations. The measured boundary layer profiles representing the boundary layer velocity normalized to the edge velocity as a function of height above the model surface were collected with the model at zero angle of attack for four different flow conditions, and were collected in a vertical plane that bisected the model's longitudinal center line at a location 635 mm from the tip of the forebody cone. The results indicate an excellent ability of the LTA system to make velocity measurements deep into the boundary layer. However, because of disturbances in the flow field caused by onboard seeding, premature transition occurred implying that upstream seeding is mandatory if model flow field integrity is to be maintained. A description and results of the flow field surveys are presented.

Measuring Surface Tension of a Flowing Soap Film

NASA Astrophysics Data System (ADS)

Sane, Aakash; Kim, Ildoo; Mandre, Shreyas

2016-11-01

It is well known that surface tension is sensitive to the presence of surfactants and many conventional methods exist to measure it. These techniques measure surface tension either by intruding into the system or by changing its geometry. Use of conventional methods in the case of a flowing soap film is not feasible because intruding the soap film changes surface tension due to Marangoni effect. We present a technique in which we measure the surface tension in situ of a flowing soap film without intruding into the film. A flowing soap film is created by letting soap solution drip between two wires. The interaction of the soap film with the wires causes the wires to deflect which can be measured. Surface tension is calculated using a relation between curvature of the wires and the surface tension. Our measurements indicate that the surface tension of the flowing soap film for our setup is around 0.05 N/m. The nature of this technique makes it favorable for measuring surface tension of flowing soap films whose properties change on intrusion.

Simulations of initial MHD experiments on the Madison Dynamo Experiment

NASA Astrophysics Data System (ADS)

O'Connell, R.; Forest, C. B.; Goldwin, J. M.; Kendrick, R. D.; Canary, H. W.; Nornberg, M. D.; Jaun, A.

1999-11-01

Initial experiments for a liquid metal MHD device have been modelled using measurements from geometrically similar water experiments. In the low B limit the water flows are the same as sodium flows. Two codes have been written to predict 1) linear stability of the system and 2) the response of the system to an externally applied vertical magnetic field, using measured velocity profiles. Predictions are made for a first set of MHD experiments, including: a) demonstration of the distortion and amplification of externally applied magnetic fields by sheared flows, b) demonstration of the β-effect by measurement of the turbulent conductivity, c) demonstration of a turbulent α effect and d) characterization of magnetic eigenmodes.

The effects of vasoactive agents on flow through saphenous vein grafts during lower-extremity peripheral vascular surgery.

PubMed

Maslow, Andrew D; Bert, Arthur; Slaiby, Jeffrey; Carney, William; Marcaccio, Edward

2007-06-01

The purpose of this study was to assess the effects of hemodynamic alterations on vein graft flow during peripheral vascular surgery. It was hypothesized that vasopressors can be administered without compromising flow through the vein grafts. Tertiary care center, university medical center. Randomized placebo-controlled double-blinded study. The effects of phenylephrine, epinephrine, milrinone, intravenous fluid, and placebo on newly constructed peripheral vein grafts were assessed in 60 patients (12 patients in each of 5 groups). Systemic and central hemodynamics were measured by using intra-arterial and pulmonary artery catheters. Vein graft flow was measured by using a transultrasonic flow probe (Transultrasonic Inc, Ithaca, NY). Phenylephrine increased systemic mean blood pressure (mBP) (68.2-94.0 mmHg, p < 0.01), systemic vascular resistance (SVR) (1,091-1,696 dynes x sec x cm(-5), p < 0.001), and vein graft flow (39.5-58.9 mL/min, p < 0.01), whereas cardiac output remained unchanged. Epinephrine resulted in increased cardiac output (4.4-6.9 L/min, p < 0.01) and mBP (72.7-89.1 mmHg, p < 0.01), whereas vein graft flow was reduced in 6 of 12 patients. Intravenous fluid administration resulted in a relatively smaller increase in graft flow (37.6-46.0 mL/min, p < 0.05), an increase in cardiac output, and an insignificant decrease in SVR. Other treatments had either little or no effect on vein graft flow. The study hypothesis was partly supported. Although both phenylephrine and epinephrine increased blood pressure, only the former increased vein graft flow in all patients. In conjunction with increases in graft flow after fluid administration, these data suggest that factors affecting vein graft flow are not just simply related to systemic hemodynamics.

An ultrasonic flowmeter for measuring dynamic liquid flow

NASA Technical Reports Server (NTRS)

Carpini, T. D.; Monteith, J. H.

1978-01-01

A novel oscillating pipe system was developed to provide dynamic calibration wherein small sinusoidal signals with amplitudes of 0.5 to 10% of the steady-state flow were added to the steady-state flow by oscillating the flowmeter relative to the fixed pipes in the flow system. Excellent agreement was obtained between the dynamic velocities derived from an accelerometer mounted on the oscillating pipe system and those sensed by the flowmeter at frequencies of 7, 19, and 30 Hz. Also described were the signal processing techniques used to retrieve the small sinusoidal signals which were obscured by the fluid turbulence.

Methods to Evaluate Influence of Onsite Septic Wastewater-Treatment Systems on Base Flow in Selected Watersheds in Gwinnett County, Georgia, October 2007

USGS Publications Warehouse

Landers, Mark N.; Ankcorn, Paul D.

2008-01-01

The influence of onsite septic wastewater-treatment systems (OWTS) on base-flow quantity needs to be understood to evaluate consumptive use of surface-water resources by OWTS. If the influence of OWTS on stream base flow can be measured and if the inflow to OWTS is known from water-use data, then water-budget approaches can be used to evaluate consumptive use. This report presents a method to evaluate the influence of OWTS on ground-water recharge and base-flow quantity. Base flow was measured in Gwinnett County, Georgia, during an extreme drought in October 2007 in 12 watersheds that have low densities of OWTS (22 to 96 per square mile) and 12 watersheds that have high densities (229 to 965 per square mile) of OWTS. Mean base-flow yield in the high-density OWTS watersheds is 90 percent greater than in the low-density OWTS watersheds. The density of OWTS is statistically significant (p-value less than 0.01) in relation to base-flow yield as well as specific conductance. Specific conductance of base flow increases with OWTS density, which may indicate influence from treated wastewater. The study results indicate considerable unexplained variation in measured base-flow yield for reasons that may include: unmeasured processes, a limited dataset, and measurement errors. Ground-water recharge from a high density of OWTS is assumed to be steady state from year to year so that the annual amount of increase in base flow from OWTS is expected to be constant. In dry years, however, OWTS contributions represent a larger percentage of natural base flow than in wet years. The approach of this study could be combined with water-use data and analyses to estimate consumptive use of OWTS.

High-pressure plastic scintillation detector for measuring radiogenic gases in flow systems

NASA Astrophysics Data System (ADS)

Schell, W. R.; Vives-Batlle, J.; Yoon, S. R.; Tobin, M. J.

1999-02-01

Radioactive gases are emitted into the atmosphere from nuclear electric power and nuclear fuel reprocessing plants, from hospitals discarding xenon used in diagnostic medicine, as well as from nuclear weapons tests. A high-pressure plastic scintillation detector was constructed to measure atmospheric levels of such radioactive gases by detecting the beta and internal conversion (IC) electron decays. Operational tests and calibrations were made that permit integration of the flow detectors into a portable Gas Analysis, Separation and Purification system (GASP). The equipment developed can be used for measuring fission gases released from nuclear reactor sources and/or as part of monitoring equipment for enforcing the Comprehensive Test Ban Treaty. The detector is being used routinely for in-line gas separation efficiency measurements, at the elevated operational pressures used for the high-pressure swing analysis system (2070 kPa) and at flow rates of 5-15 l/min [1, 2]. This paper presents the design features, operational methods, calibration, and detector applications.

Measurements of ion temperature and flow of pulsed plasmas produced by a magnetized coaxial plasma gun device using an ion Doppler spectrometer

NASA Astrophysics Data System (ADS)

Kitagawa, Y.; Sakuma, I.; Iwamoto, D.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

It is important to know surface damage characteristics of plasma-facing component materials during transient heat and particle loads such as type I ELMs. A magnetized coaxial plasma gun (MCPG) device has been used as transient heat and particle source in ELM simulation experiments. Characteristics of pulsed plasmas produced by the MCPG device play an important role for the plasma material interaction. In this study, ion temperature and flow velocity of pulsed He plasmas were measured by an ion Doppler spectrometer (IDS). The IDS system consists of a light collection system including optical fibers, 1m-spectrometer and a 16 channel photomultiplier tube (PMT) detector. The IDS system measures the width and Doppler shift of HeII (468.58 nm) emission line with the time resolution of 1 μs. The Doppler broadened and shifted spectra were measured with 45 and 135 degree angles with respect to the plasmoid traveling direction. The observed emission line profile was represented by sum of two Gaussian components to determine the temperature and flow velocity. The minor component at around the wavelength of zero-velocity was produced by the stationary plasma. As the results, the ion velocity and temperature were 68 km/s and 19 eV, respectively. Thus, the He ion flow energy is 97 eV. The observed flow velocity agrees with that measured by a time of flight technique.

Method and apparatus to measure vapor pressure in a flow system

DOEpatents

Grossman, M.W.; Biblarz, O.

1991-10-15

The present invention is directed to a method for determining, by a condensation method, the vapor pressure of a material with a known vapor pressure versus temperature characteristic, in a flow system particularly in a mercury isotope enrichment process. 2 figures.

Non-invasive measurement of pulse wave velocity using transputer-based analysis of Doppler flow audio signals.

PubMed

Stewart, W R; Ramsey, M W; Jones, C J

1994-08-01

A system for the measurement of arterial pulse wave velocity is described. A personal computer (PC) plug-in transputer board is used to process the audio signals from two pocket Doppler ultrasound units. The transputer is used to provide a set of bandpass digital filters on two channels. The times of excursion of power through thresholds in each filter are recorded and used to estimate the onset of systolic flow. The system does not require an additional spectrum analyser and can work in real time. The transputer architecture provides for easy integration into any wider physiological measurement system.

Dynamic viscoelasticity measurement under alternative torque using electromagnetically spinning method with quadruple electromagnets.

PubMed

Matsuura, Yusuke; Hirano, Taichi; Sakai, Keiji

2017-07-01

In this study, we developed a novel type of rheological measurement system. Here, a spherical probe is driven to rotate periodically by applying torques using quadruple electromagnets in a noncontact manner. Moreover, this system is an enhancement of our electromagnetically spinning (EMS) viscometer, which is widely used for measuring rheological flow curves in various industrial fields. The quadruple EMS method provides the frequency spectrum of viscoelasticity, in addition to shear viscosity, in a steady flow by switching the operation modes of the driving torque. We show the results obtained for Newtonian fluids and viscoelastic materials and demonstrate the validity of the system.

Monitoring of multiphase flows for superconducting accelerators and others applications

NASA Astrophysics Data System (ADS)

Filippov, Yu. P.; Kakorin, I. D.; Kovrizhnykh, A. M.; Miklayev, V. M.

2017-07-01

This paper is a review on implementation of measuring systems for two-phase helium, hydrogen, liquefied natural gas (LNG), and oil-formation/salty water flows. Two types of such systems are presented. The first type is based on two-phase flow-meters combining void fraction radio-frequency (RF) sensors and narrowing devices. They can be applied for superconducting accelerators cooled with two-phase helium, refueling hydrogen system for space ships and some applications in oil production industry. The second one is based on combination of a gamma-densitometer and a narrowing device. These systems can be used to monitor large two-phase LNG and oil-formation water flows. An electronics system based on a modular industrial computer is described as well. The metrological characteristics for different flow-meters are presented and the obtained results are discussed. It is also shown that the experience gained allows separationless flow-meter for three-phase oil-gas-formation water flows to be produced.

Flow field description of the Space Shuttle Vernier reaction control system exhaust plumes

NASA Technical Reports Server (NTRS)

Cerimele, Mary P.; Alred, John W.

1987-01-01

The flow field for the Vernier Reaction Control System (VRCS) jets of the Space Shuttle Orbiter has been calculated from the nozzle throat to the far-field region. The calculations involved the use of recently improved rocket engine nozzle/plume codes. The flow field is discussed, and a brief overview of the calculation techniques is presented. In addition, a proposed on-orbit plume measurement experiment, designed to improve future estimations of the Vernier flow field, is addressed.

Using archived ITS data to measure the operational benefits of a system-wide adaptive ramp metering system : appendix online 10 : OR\\0x2010217 NB ramp flow & ML speed-flow plots.

DOT National Transportation Integrated Search

2008-12-01

The appendix includes various ramp flow and ML speed-flow plots: OR-217 NB, 72nd MP 6.61; OR-217 NB, 99W-EB MP 5.9; OR-217 NB, 99W-WB MP 5.85; OR-217 NB, Greenburg MP 4.65; OR-217 NB, Scholls MP 3.85; OR-217 NB, Denney MP 2.68; OR-217 NB, Allen MP 2....

Can a simple dynamical system describe the interplay between drag and buoyancy in terrain-induced canopy flows?

NASA Astrophysics Data System (ADS)

De Roo, Frederik; Banerjee, Tirtha

2017-04-01

Under non-neutral conditions and in the presence of topography the dynamics of turbulent flow within a canopy is not yet completely understood. This has implications for the measurement of surface-atmosphere exchange by means of eddy-covariance. For example the measurement of carbon dioxide fluxes are strongly influenced if drainage flows happen during night, when the flow within the canopy decouples from the flow aloft. In the present work, we investigate the dynamics of terrain-induced turbulent flow within sloped canopies. We concentrate on the presence of oscillatory behavior in the flow variables in terms of switching of flow regimes by conducting linear stability analysis. We revisit and correct the simplified theory that exists in the literature, which is based on the interplay between the drag force and the buoyancy. We find that the simplified description of this dynamical system cannot exhibit the observed richness of the dynamics. To tackle the full spatiotemporal dynamical system theoretically is beyond the scope of this work, although we can make some qualitative arguments. Additionally, we make use of large-eddy simulation of a three-dimensional hill covered by a homogeneous forest and analyze phase synchronization behavior of the major terms in the momentum budget to explore the turbulent dynamics in more detail.

[Echocardiography in Boid snakes: Demonstration and blood flow measurements].

PubMed

Schroff, S; Starck, J M; Krautwald-Junghanns, M-E; Pees, M

2012-01-01

Comparative echocardiography and blood flow measurements in different boid species. 51 healthy snakes from seven different species were examined echocardiographically under standardized conditions. The heart and the great vessels were displayed using 2-D-ultrasonography. Pulsed-wave doppler technique measurements of the blood flow within the vessels were performed and results analyzed statistically. The examinations could be performed in non-sedated snakes in ventral recumbency. The best image quality was obtained using the ventrolateral coupling site. An examination scheme applicable to all examined snake species was established. Diversity in the anatomy of vessels could be detected in different snake species. A characteristic shape of the curve demonstrating the blood flow against time could be shown for the respective vessels. There were positive correlations between the size of the snakes and the absolute blood flow (total flow, systemic flow, pulmonary flow to body length: p<0.001; r=0.770; r=0.627; r=0.766; respectively to body mass: p<0.001; r=0.815; r=0.698; r=0.788), as well as negative correlations between the size of the animals and the blood flow relative to body mass (total flow, systemic flow, pulmonary flow to body length: p<0.001; r=-0.533; r=-0.512; r=-0.478; respectively total flow to body mass: p<0.001; r=-0.768). When using standardized conditions, echocardiography in boid snakes is a useful diagnostic tool for the assessment of cardiac function. Reference values provided in this study serve as a basis for ultrasound examination in veterinary practice.

Design of a High Intensity Turbulent Combustion System

DTIC Science & Technology

2015-05-01

nth repetition of a turbulent-flow experiment. [1] .................... 8 Figure 2. 3: Velocity measurement on the n th repetition of a turbulent-flow...measurement on the n th repetition of a turbulent-flow experiment. u(t) = U + u’(t...event such as P ≈ [ U < N ms-1 ]. The random variable U can be characterized by its probability density function (PDF). The probability of an event

The Effects of Sampling Probe Design and Sampling Techniques on Aerosol Measurements

DTIC Science & Technology

1975-05-01

Schematic of Extraction and Sampling System 39 16. Filter Housing 40 17. Theoretical Isokinetic Flow Requirements of the EPA Sampling...from the flow parameters based on a zero-error assumption at isokinetic sampling conditions. Isokinetic , or equal velocity sampling, was...prior to testing the probes. It was also used to measure the flow field adjacent to the probe inlets to determine the isokinetic condition of the

Ultrasonic Doppler measurement of renal artery blood flow

NASA Technical Reports Server (NTRS)

Freund, W. R.; Meindl, J. D.

1975-01-01

An extensive evaluation of the practical and theoretical limitations encountered in the use of totally implantable CW Doppler flowmeters is provided. Theoretical analyses, computer models, in-vitro and in-vivo calibration studies describe the sources and magnitudes of potential errors in the measurement of blood flow through the renal artery, as well as larger vessels in the circulatory system. The evaluation of new flowmeter/transducer systems and their use in physiological investigations is reported.

Nitric Oxide PLIF Measurements in the Hypersonic Materials Environmental Test System (HYMETS)

NASA Technical Reports Server (NTRS)

Inman, Jennifer A.; Bathel, Brett F.; Johansen, Craig T.; Danehy, Paul M.; Jones, Stephen B.; Gragg, Jeffrey G.; Splinter, Scott C.; McRae, Colin D.

2013-01-01

Planar laser-induced fluorescence (PLIF) of naturally occurring nitric oxide (NO) has been used to obtain instantaneous flow visualization images, and to make both radial and axial velocity measurements in the HYMETS (Hypersonic Materials Environmental Test System) 400 kW arc-heated wind tunnel at NASA Langley Research Center. This represents the first application of NO PLIF flow visualization in HYMETS. Results are presented at selected facility run conditions, including some in a simulated Earth atmosphere (75% nitrogen, 20% oxygen, 5% argon) and others in a simulated Martian atmosphere (71% carbon dioxide, 24% nitrogen, 5% argon), for specific bulk enthalpies ranging from 6.5 MJ/kg to 18.4 MJ/kg. Flow visualization images reveal the presence of large scale unsteady flow structures, and indicate nitric oxide fluorescence signal over more than 70% of the core flow for specific bulk enthalpies below about 11 MJ/kg, but over less than 10% of the core flow for specific bulk enthalpies above about 16 MJ/kg. Axial velocimetry was performed using molecular tagging velocimetry (MTV). Axial velocities of about 3 km/s were measured along the centerline. Radial velocimetry was performed by scanning the wavelength of the narrowband laser and analyzing the resulting Doppler shift. Radial velocities of +/- 0.5 km/s were measured.

Water-level database update for the Death Valley regional groundwater flow system, Nevada and California, 1907-2007

USGS Publications Warehouse

Pavelko, Michael T.

2010-01-01

The water-level database for the Death Valley regional groundwater flow system in Nevada and California was updated. The database includes more than 54,000 water levels collected from 1907 to 2007, from more than 1,800 wells. Water levels were assigned a primary flag and multiple secondary flags that describe hydrologic conditions and trends at the time of the measurement and identify pertinent information about the well or water-level measurement. The flags provide a subjective measure of the relative accuracy of the measurements and are used to identify which water levels are appropriate for calculating head observations in a regional transient groundwater flow model. Included in the report appendix are all water-level data and their flags, selected well data, and an interactive spreadsheet for viewing hydrographs and well locations.

Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation

NASA Technical Reports Server (NTRS)

Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

2008-01-01

This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

Frost sensor for use in defrost controls for refrigeration

DOEpatents

French, Patrick D.; Butz, James R.; Veatch, Bradley D.; O'Connor, Michael W.

2002-01-01

An apparatus and method for measuring the total thermal resistance to heat flow from the air to the evaporative cooler fins of a refrigeration system. The apparatus is a frost sensor that measures the reduction in heat flow due to the added thermal resistance of ice (reduced conduction) as well as the reduction in heat flow due to the blockage of airflow (reduced convection) from excessive ice formation. The sensor triggers a defrost cycle when needed, instead of on a timed interval. The invention is also a method for control of frost in a system that transfers heat from air to a refrigerant along a thermal path. The method involves measuring the thermal conductivity of the thermal path from the air to the refrigerant, recognizing a reduction in thermal conductivity due to the thermal insulation effect of the frost and due to the loss of airflow from excessive ice formation; and controlling the defrosting of the system.

Hard metal exposures. Part 1: Observed performance of three local exhaust ventilation systems.

PubMed

Guffey, S E; Simcox, N; Booth, D W; Hibbard, R; Stebbins, A

2000-04-01

Not every ventilation system performs as intended; much can be learned when they do not. The purpose of this study was to compare observed initial performance to expected levels for three saw-reconditioning shop ventilation systems and to characterize the changes in performance of the systems over a one-year period. These three local exhaust ventilation systems were intended to control worker exposures to cobalt, cadmium, and chromium during wet grinding, dry grinding, and welding/brazing activities. Prior to installation the authors provided some design guidance based on Industrial Ventilation, a Manual of Recommended Practice. However, the authors had limited influence on the actual installation and operation and no line authority for the systems. In apparent efforts to cut costs and to respond to other perceived needs, the installed systems deviated from the specifications used in pressure calculations in many important aspects, including adding branch ducts, use of flexible ducts, the choice of fans, and the construction of some hoods. After installation of the three systems, ventilation measurements were taken to determine if the systems met design specifications, and worker exposures were measured to determine effectiveness. The results of the latter will be published as a companion article. The deviations from design and maintenance failures may have adversely affected performance. From the beginning to the end of the study period the distribution of air flow never matched the design specifications for the systems. The observed air flows measured within the first month of installation did not match the predicated design air flows for any of the systems, probably because of the differences between the design and the installed system. Over the first year of operation, hood air flow variability was high due to inadequate cleaning of the sticky process materials which rapidly accumulated in the branch ducts. Poor distribution of air flows among branch ducts frequently produced individual hood air flows that were far below specified design levels even when the total air flow through that system was more than adequate. To experienced practitioners, it is not surprising that deviations from design recommendations and poor maintenance would be associated with poor system performance. Although commonplace, such experiences have not been documented in peer-reviewed publications to date. This publication is a first step in providing that documentation.

Flow interaction in the combustor-diffusor system of industrial gas turbines

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

Agrawal, A.K.; Kapat, J.S.; Yang, T.

1996-05-01

This paper presents an experimental/computational study of cold flow in the combustor-diffuser system of industrial gas turbines to address issues relating to flow interactions and pressure losses in the pre- and dump diffusers. The present configuration with can annular combustors differs substantially from the aircraft engines which typically use a 360 degree annular combustor. Experiments were conducted in a one-third scale, annular 360-degree model using several can combustors equispaced around the turbine axis. A 3-D computational fluid dynamics analysis employing the multidomain procedure was performed to supplement the flow measurements. The measured data correlated well with the computations. The airflowmore » in the dump diffuser adversely affected the prediffuser flow by causing it to accelerate in the outer region at the prediffuser exit. This phenomenon referred to as the sink-effect also caused a large fraction of the flow to bypass much of the dump diffuser and go directly from the prediffuser exit to the bypass air holes on the combustor casing, thereby, rendering the dump diffuser ineffective in diffusing the flow. The dump diffuser was occupied by a large recirculation region which dissipated the flow kinetic energy. Approximately 1.2 dynamic head at the prediffuser inlet was lost in the combustor-diffuser system; much of it in the dump diffuser where the fluid passed through the narrow gaps and pathways. Strong flow interactions in the combustor-diffuser system indicate the need for design modifications which could not be addressed by empirical correlations based on simple flow configurations.« less

A vision-based tool for the control of hydraulic structures in sewer systems

NASA Astrophysics Data System (ADS)

Nguyen, L.; Sage, D.; Kayal, S.; Jeanbourquin, D.; Rossi, L.

2009-04-01

During rain events, the total amount of the wastewater/storm-water mixture cannot be treated in the wastewater treatment plant; the overflowed water goes directly into the environment (lakes, rivers, streams) via devices called combined sewers overflows (CSOs). This water is untreated and is recognized as an important source of pollution. In most cases, the quantity of overflowed water is unknown due to high hydraulic turbulences during rain events; this quantity is often significant. For this reason, the monitoring of the water flow and the water level is of crucial environmental importance. Robust monitoring of sewer systems is a challenging task to achieve. Indeed, the environment inside sewers systems is inherently harsh and hostile: constant humidity of 100%, fast and large water level changes, corrosive atmosphere, presence of gas, difficult access, solid debris inside the flow. A flow monitoring based on traditional probes placed inside the water (such as Doppler flow meter) is difficult to conduct because of the solid material transported by the flow. Probes placed outside the flow such as ultrasonic water level probes are often used; however the measurement is generally done on only one particular point. Experience has shown that the water level in CSOs during rain events is far from being constant due to hydraulic turbulences. Thus, such probes output uncertain information. Moreover, a check of the data reliability is impossible to achieve. The HydroPix system proposes a novel approach to the monitoring of sewers based on video images, without contact with the water flow. The goal of this system is to provide a monitoring tool for wastewater system managers (end-users). The hardware was chosen in order to suit the harsh conditions of sewers system: Cameras are 100% waterproof and corrosion-resistant; Infra-red LED illumination systems are used (waterproof, low power consumption); A waterproof case contains the registration and communication system. The monitoring software has the following requirements: visual analysis of particular hydraulic behavior, automatic vision-based flow measurements, automatic alarm system for particular events (overflows, risk of flooding, etc), database for data management (images, events, measurements, etc.), ability to be controlled remotely. The software is implemented in modular server/client architecture under LabVIEW development system. We have conducted conclusive in situ tests in various sewers configurations (CSOs, storm-water sewerage, WWTP); they have shown the ability of the HydroPix to perform accurate monitoring of hydraulic structures. Visual information demonstrated a better understanding of the flow behavior in complex and difficult environment.

System and method for measuring permeability of materials

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John

2013-07-09

Systems and methods are provided for measuring the permeance of a material. The permeability of the material may also be derived. Systems typically provide a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Fluid permeability measurement system and method

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John [Oak Ridge, TN

2008-02-05

A system for measuring the permeance of a material. The permeability of the material may also be derived. The system provides a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Material permeance measurement system and method

DOEpatents

Hallman, Jr., Russell Louis; Renner, Michael John [Oak Ridge, TN

2012-05-08

A system for measuring the permeance of a material. The permeability of the material may also be derived. The system provides a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

On discharge from poppet valves: effects of pressure and system dynamics

NASA Astrophysics Data System (ADS)

Winroth, P. M.; Ford, C. L.; Alfredsson, P. H.

2018-02-01

Simplified flow models are commonly used to design and optimize internal combustion engine systems. The exhaust valves and ports are modelled as straight pipe flows with a corresponding discharge coefficient. The discharge coefficient is usually determined from steady-flow experiments at low pressure ratios and at fixed valve lifts. The inherent assumptions are that the flow through the valve is insensitive to the pressure ratio and may be considered as quasi-steady. The present study challenges these two assumptions through experiments at varying pressure ratios and by comparing measurements of the discharge coefficient obtained under steady and dynamic conditions. Steady flow experiments were performed in a flow bench, whereas the dynamic measurements were performed on a pressurized, 2 l, fixed volume cylinder with one or two moving valves. In the latter experiments an initial pressure (in the range 300-500 kPa) was established whereafter the valve(s) was opened with a lift profile corresponding to different equivalent engine speeds (in the range 800-1350 rpm). The experiments were only concerned with the blowdown phase, i.e. the initial part of the exhaustion process since no piston was simulated. The results show that the process is neither pressure-ratio independent nor quasi-steady. A measure of the "steadiness" has been defined, relating the relative change in the open flow area of the valve to the relative change of flow conditions in the cylinder, a measure that indicates if the process can be regarded as quasi-steady or not.

Brief Communication: A low-cost Arduino®-based wire extensometer for earth flow monitoring

NASA Astrophysics Data System (ADS)

Guerriero, Luigi; Guerriero, Giovanni; Grelle, Gerardo; Guadagno, Francesco M.; Revellino, Paola

2017-06-01

Continuous monitoring of earth flow displacement is essential for the understanding of the dynamic of the process, its ongoing evolution and designing mitigation measures. Despite its importance, it is not always applied due to its expense and the need for integration with additional sensors to monitor factors controlling movement. To overcome these problems, we developed and tested a low-cost Arduino-based wire-rail extensometer integrating a data logger, a power system and multiple digital and analog inputs. The system is equipped with a high-precision position transducer that in the test configuration offers a measuring range of 1023 mm and an associated accuracy of ±1 mm, and integrates an operating temperature sensor that should allow potential thermal drift that typically affects this kind of systems to be identified and corrected. A field test, conducted at the Pietrafitta earth flow where additional monitoring systems had been installed, indicates a high reliability of the measurement and a high monitoring stability without visible thermal drift.

In vitro evaluation of the effect of aortic compliance on pediatric intra-aortic balloon pumping.

PubMed

Minich, L L; Tani, L Y; Hawkins, J A; Bartkowiak, R R; Royall, M L; Pantalos, G M

2001-04-01

OBJECTIVES: To evaluate the effect of aortic compliance on pediatric intra-aortic balloon pumping (IABP). DESIGN: In vitro study using a mechanical model of the pediatric left heart circulation. SETTING: Cardiovascular fluid dynamics research laboratory. SUBJECT: Pulsatile flow system simulating the pediatric left heart circulation and two different aortas with compliances comparable to those of the pediatric aorta (0.12 and 0.07 mL/mm Hg). INTERVENTIONS: Measurements were made at a baseline peak aortic flow of 4 L/min, at simulated shock (1.7 L/min), and with 1:1 IABP (rates, 130 and 150 bpm; balloon volumes, 2.5 and 5.0 mL). MEASUREMENTS AND MAIN RESULTS: Peak flow rates were measured in the ascending aorta, coronary arterial system, and brachiocephalic arterial systems. Aortic pressure was measured in the ascending aorta. For both aortas (0.12 and 0.07 mL/mm Hg), IABP resulted in diastolic augmentation (38 +/- 8 and 43 +/- 16 mm Hg) and afterload reduction (4 +/- 2 and 6 +/- 3 mm Hg). For both aortas, compared to shock, IABP resulted in significant increases in coronary arterial and brachiocephalic arterial flow and aortic pressure for both aortas. Aortic flow significantly increased only in the less-compliant aorta. CONCLUSIONS: In a laboratory model of pediatric left heart circulation, IABP results in diastolic augmentation, afterload reduction, and improved hemodynamics, even in aortas of greater compliance.

Determining Aqueous Fullerene Particle Size Distributions by Asymmetric Flow Field-Flow Fractionation (AF4) without Surfactants

EPA Science Inventory

To determine the behavior of nanoparticles in environmental systems, methods must be developed to measure nanoparticle size. Asymmetric Flow Field Flow Fractionation (AF4) is an aqueous compatible size separation technique which is able to separate particles from 1 nm to 10 µm in...

International Instrumentation Symposium, 39th, Albuquerque, NM, May 2-6, 1993, Proceedings

NASA Astrophysics Data System (ADS)

Various papers on instrumentation are presented. The general topics addressed include: data acquisition and processing, wind tunnels, pressure measurements, thermal measurements, force measurements, aerospace, metrology, flow measurements, real-time systems, measurement uncertainty, data analysis and calibration, computer applications, special tests, reentry vehicle systems, and human engineering.

[Development of automatic urine monitoring system].

PubMed

Wei, Liang; Li, Yongqin; Chen, Bihua

2014-03-01

An automatic urine monitoring system is presented to replace manual operation. The system is composed of the flow sensor, MSP430f149 single chip microcomputer, human-computer interaction module, LCD module, clock module and memory module. The signal of urine volume is captured when the urine flows through the flow sensor and then displayed on the LCD after data processing. The experiment results suggest that the design of the monitor provides a high stability, accurate measurement and good real-time, and meets the demand of the clinical application.

Detection of early changes in lung-cell cytology by flow-systems analysis techniques. Progress report, January 1--June 30, 1976

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

Steinkamp, J. A.; Hansen, K. M.; Wilson, J. S.

1976-08-01

This report summarizes results of preliminary experiments to develop cytological and biochemical indicators for estimating damage to respiratory epithelium exposed to toxic agents associated with the by-products of nonnuclear energy production using advanced flow-systems cell-analysis technologies. Since initiation of the program one year ago, progress has been made in obtaining adequate numbers of exfoliated lung cells from the Syrian hamster for flow analysis; cytological techniques developed on human exfoliated gynecological samples have been adapted to hamster lung epithelium for obtaining single-cell suspensions; and lung-cell samples have been initially characterized based on DNA content, total protein, nuclear and cytoplasmic size, andmore » multiangle light-scatter measurements. Preliminary results from measurements of the above parameters which recently became available are described in this report. As the flow-systems technology is adapted further to analysis of exfoliated lung cells, measurements of changes in physical and biochemical cellular properties as a function of exposure to toxic agents will be performed.« less

Measurements of drag and flow over biofilm

NASA Astrophysics Data System (ADS)

Hartenberger, Joel; Gose, James W.; Perlin, Marc; Ceccio, Steven L.

2017-11-01

Microbial `slime' biofilms detrimentally affect the performance of every day systems from medical devices to large ocean-going vessels. In flow applications, the presence of biofilm typically results in a drag increase and may alter the turbulence in the adjacent boundary layer. Recent studies emphasize the severity of the drag penalty associated with soft biofouling and suggest potential mechanisms underlying the increase; yet, fundamental questions remain-such as the role played by compliance and the contribution of form drag to the overall resistance experienced by a fouled system. Experiments conducted on live biofilm and 3D printed rigid replicas in the Skin-Friction Flow Facility at the University of Michigan seek to examine these factors. The hydrodynamic performance of the biofilms grown on test panels was evaluated through pressure drop measurements as well as conventional and microscale PIV. High-resolution, 3D rigid replicas of select cases were generated via additive manufacturing using surface profiles obtained from a laser scanning system. Drag and flow measurements will be presented along with details of the growth process and the surface profile characterization method.

Continuous measurements of flow rate in a shallow gravel-bed river by a new acoustic system

NASA Astrophysics Data System (ADS)

Kawanisi, K.; Razaz, M.; Ishikawa, K.; Yano, J.; Soltaniasl, M.

2012-05-01

The continuous measurement of river discharge for long periods of time is crucial in water resource studies. However, the accurate estimation of river discharge is a difficult and labor-intensive procedure; thus, a robust and efficient method of measurement is required. Continuous measurements of flowrate have been carried out in a wide, shallow gravel bed river (water depth ≈ 0.6 m under low-flow conditions, width ≈ 115 m) using Fluvial Acoustic Tomography System (FATS) that has 25 kHz broadband transducers with horizontally omnidirectional and vertically hemispherical beam patterns. Reciprocal sound transmissions were performed between the two acoustic stations located diagonally on both sides of the river. The horizontal distance between the transducers was 301.96 m. FATS enabled the measurement of the depth- and range-averaged sound speed and flow velocity along the ray path. In contrast to traditional point/transect measurements of discharge, in a fraction of a second, FATS covers the entire cross section of river in a single measurement. The flow rates measured by FATS were compared to those estimated by moving boat Acoustic Doppler Current Profiler (ADCP) and rating curve (RC) methods. FATS estimates were in good agreement with ADCP estimates over a range of 20 to 65 m3 s-1. The RMS of residual between the two measurements was 2.41 m3 s-1. On the other hand the flowrate by RC method fairly agreed with FATS estimates for greater discharges than around 40 m3 s-1. This inconsistency arises from biased RC estimates in low flows. Thus, the flow rates derived from FATS could be considered reliable.

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

PubMed

Pan, Pengmin; McDonald, Timothy; Fulton, John; Via, Brian; Hung, John

2016-12-23

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.

Miniaturized flow injection analysis system

DOEpatents

Folta, James A.

1997-01-01

A chemical analysis technique known as flow injection analysis, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38.times.25.times.3 mm, but can be designed for gas analysis and be substantially smaller in construction.

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

NASA Technical Reports Server (NTRS)

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.

Comparison of Tissue Heat Balance- and Thermal Dissipation-Derived Sap Flow Measurements in Ring-Porous Oaks and a Pine

PubMed Central

Renninger, Heidi J.; Schäfer, Karina V. R.

2012-01-01

Sap flow measurements have become integral in many physiological and ecological investigations. A number of methods are used to estimate sap flow rates in trees, but probably the most popular is the thermal dissipation (TD) method because of its affordability, relatively low power consumption, and ease of use. However, there have been questions about the use of this method in ring-porous species and whether individual species and site calibrations are needed. We made concurrent measurements of sap flow rates using TD sensors and the tissue heat balance (THB) method in two oak species (Quercus prinus Willd. and Quercus velutina Lam.) and one pine (Pinus echinata Mill.). We also made concurrent measurements of sap flow rates using both 1 and 2-cm long TD sensors in both oak species. We found that both the TD and THB systems tended to match well in the pine individual, but sap flow rates were underestimated by 2-cm long TD sensors in five individuals of the two ring-porous oak species. Underestimations of 20–35% occurred in Q. prinus even when a “Clearwater” correction was applied to account for the shallowness of the sapwood depth relative to the sensor length and flow rates were underestimated by up to 50% in Q. velutina. Two centimeter long TD sensors also underestimated flow rates compared with 1-cm long sensors in Q. prinus, but only at large flow rates. When 2-cm long sensor data in Q. prinus were scaled using the regression with 1-cm long data, daily flow rates matched well with the rates measured by the THB system. Daily plot level transpiration estimated using TD sap flow rates and scaled 1 cm sensor data averaged about 15% lower than those estimated by the THB method. Therefore, these results suggest that 1-cm long sensors are appropriate in species with shallow sapwood, however more corrections may be necessary in ring-porous species. PMID:22661978

Impedance probe to measure local void fraction profiles

NASA Astrophysics Data System (ADS)

Teyssedou, A.; Tapucu, A.; Lortie, M.

1988-04-01

A conductivity-type local void measurement system has been developed. The effects of the sensor tip geometry, the unbalance of the front-end bridge, the comparator threshold level, and the mass fluxes on the response of the instrument have been studied. The system has been calibrated under air-water two-phase flow conditions using the quick-closing-valve technique. Comparison of the void profiles obtained with the conductivity probe with those obtained using an optical probe confirms the applicability of this system for two-phase (air-water) flows.

Microwave sensing of moisture content and bulk density in flowing grain

USDA-ARS?s Scientific Manuscript database

Moisture content and bulk density were determined from measurement of the dielectric properties of flowing wheat kernels at a single microwave frequency (5.8 GHz). The measuring system consisted of two high-gain microwave patch antennas mounted on opposite sides of rectangular chute and connected to...

Flow Control and Measurement in Electric Propulsion Systems: Towards an AIAA Reference Standard

DTIC Science & Technology

2013-10-01

the spacecraft sensors, although some improvement can be made by averaging several measurements together. 3. Thermal Mass Gauging Thermal Mass...flow controllers (MFCs) to measure and control propellant into EP devices. To determine several key thruster performance parameters with a low level...the specified time interval may not be known. A first recourse is to perform several measurements and examine the linearity. In cases where the

Useful method to monitor the physiological effects of alcohol ingestion by combination of micro-integrated laser Doppler blood flow meter and arm-raising test.

PubMed

Iwasaki, Wataru; Nogami, Hirofumi; Ito, Hiroki; Gotanda, Takeshi; Peng, Yao; Takeuchi, Satoshi; Furue, Masutaka; Higurashi, Eiji; Sawada, Renshi

2012-10-01

Alcohol has a variety of effects on the human body, affecting both the sympathetic and parasympathetic nervous system. We examined the peripheral blood flow of alcohol drinkers using a micro-integrated laser Doppler blood flow meter (micro-electromechanical system blood flow sensor). An increased heart rate and blood flow was recorded at the earlobe after alcohol ingestion, and we observed strong correlation between blood flow, heart rate, and breath alcohol content in light drinkers; but not heavy drinkers. We also found that the amplitude of pulse waves measured at the fingertip during an arm-raising test significantly decreased on alcohol consumption, regardless of the individual's alcohol tolerance. Our micro-electromechanical system blood flow sensor successfully detected various physiological changes in peripheral blood circulation induced by alcohol consumption.

Research on MEMS sensor in hydraulic system flow detection

NASA Astrophysics Data System (ADS)

Zhang, Hongpeng; Zhang, Yindong; Liu, Dong; Ji, Yulong; Jiang, Jihai; Sun, Yuqing

2011-05-01

With the development of mechatronics technology and fault diagnosis theory, people regard flow information much more than before. Cheap, fast and accurate flow sensors are urgently needed by hydraulic industry. So MEMS sensor, which is small, low cost, well performed and easy to integrate, will surely play an important role in this field. Based on the new method of flow measurement which was put forward by our research group, this paper completed the measurement of flow rate in hydraulic system by setting up the mathematical model, using numerical simulation method and doing physical experiment. Based on viscous fluid flow equations we deduced differential pressure-velocity model of this new sensor and did optimization on parameters. Then, we designed and manufactured the throttle and studied the velocity and pressure field inside the sensor by FLUENT. Also in simulation we get the differential pressure-velocity curve .The model machine was simulated too to direct experiment. In the static experiments we calibrated the MEMS sensing element and built some sample sensors. Then in a hydraulic testing system we compared the sensor signal with a turbine meter. It presented good linearity and could meet general hydraulic system use. Based on the CFD curves, we analyzed the error reasons and made some suggestion to improve. In the dynamic test, we confirmed this sensor can realize high frequency flow detection by a 7 piston-pump.

Research on MEMS sensor in hydraulic system flow detection

NASA Astrophysics Data System (ADS)

Zhang, Hongpeng; Zhang, Yindong; Liu, Dong; Ji, Yulong; Jiang, Jihai; Sun, Yuqing

2010-12-01

With the development of mechatronics technology and fault diagnosis theory, people regard flow information much more than before. Cheap, fast and accurate flow sensors are urgently needed by hydraulic industry. So MEMS sensor, which is small, low cost, well performed and easy to integrate, will surely play an important role in this field. Based on the new method of flow measurement which was put forward by our research group, this paper completed the measurement of flow rate in hydraulic system by setting up the mathematical model, using numerical simulation method and doing physical experiment. Based on viscous fluid flow equations we deduced differential pressure-velocity model of this new sensor and did optimization on parameters. Then, we designed and manufactured the throttle and studied the velocity and pressure field inside the sensor by FLUENT. Also in simulation we get the differential pressure-velocity curve .The model machine was simulated too to direct experiment. In the static experiments we calibrated the MEMS sensing element and built some sample sensors. Then in a hydraulic testing system we compared the sensor signal with a turbine meter. It presented good linearity and could meet general hydraulic system use. Based on the CFD curves, we analyzed the error reasons and made some suggestion to improve. In the dynamic test, we confirmed this sensor can realize high frequency flow detection by a 7 piston-pump.

Portable Fluorescence Imaging System for Hypersonic Flow Facilities

NASA Technical Reports Server (NTRS)

Wilkes, J. A.; Alderfer, D. W.; Jones, S. B.; Danehy, P. M.

2003-01-01

A portable fluorescence imaging system has been developed for use in NASA Langley s hypersonic wind tunnels. The system has been applied to a small-scale free jet flow. Two-dimensional images were taken of the flow out of a nozzle into a low-pressure test section using the portable planar laser-induced fluorescence system. Images were taken from the center of the jet at various test section pressures, showing the formation of a barrel shock at low pressures, transitioning to a turbulent jet at high pressures. A spanwise scan through the jet at constant pressure reveals the three-dimensional structure of the flow. Future capabilities of the system for making measurements in large-scale hypersonic wind tunnel facilities are discussed.

New diesel injection nozzle flow measuring device

NASA Astrophysics Data System (ADS)

Marčič, Milan

2000-04-01

A new measuring device has been developed for diesel injection nozzle testing, allowing measuring of the steady flow through injection nozzle and the injection rate. It can be best applied for measuring the low and high injection rates of the pintle and single hole nozzle. In steady flow measuring the fuel pressure at the inlet of the injection nozzle is 400 bar. The sensor of the measuring device measures the fuel charge, resulting from fuel rubbing in the fuel injection system, as well as from the temperature gradient in the sensor electrode. The electric charge is led to the charge amplifier, where it is converted into electric current and amplified. The amplifier can be used also to measure the mean injection rate value.

Tubing length for long-term oxygen therapy.

PubMed

Aguiar, Carolina; Davidson, Josy; Carvalho, Andréa K; Iamonti, Vinícius C; Cortopassi, Felipe; Nascimento, Oliver A; Jardim, José R

2015-02-01

Most patients on long-term oxygen therapy use stationary oxygen delivery systems. It is not uncommon for guidelines to instruct patients to use tubing lengths no longer than 19.68 ft (6 m) when using an oxygen concentrator and 49.21 ft (15 m) when using cylinders. However, these concepts are not based on sufficient evidence. Thus, our objective was to evaluate whether a 98.42-ft (30-m) tubing length affects oxygen flow and FIO2 delivery from 1 cylinder and 2 oxygen concentrators. The 3 oxygen delivery systems were randomly selected, and 1, 3, and 5 L/min flows and FIO2 were measured 5 times at each flow at the proximal and distal outlets of the tubing by a gas-flow analyzer. Paired Student t test was used to analyze the difference between flows and FIO2 at proximal and distal outlets of tubing length. A total of 45 flows were measured between proximal and distal outlets of the 98.42-ft (30-m) tubing. Flows were similar for 1 and 3 L/min, but distal flow was higher than proximal flow at 5 L/min (5.57×5.14 L/min, P<.001). FIO2 was lower at distal than proximal outlet tubing at flows 1, 3, and 5 L/min, but the mean difference between measurements was less than 1%. Tubing length of 98.42 ft (30 m) may be used by patients for home delivery oxygen with flows up to 5 L/min, as there were no important changes in flows or FIO2. Copyright © 2015 by Daedalus Enterprises.

[3-channels data acquisition system based on single-chip-microcomputer used in the measurement of coronary sinus blood flow].

PubMed

Li, Z; Fan, Y; Chen, G

1999-07-01

The coronary sinus blood flow can be figured out, which based on the principle of thermodilution, so long as gets the temperature of blood, indicator and mixture of blood and indicator respectively. This system is a smart slave module with single-chip-microcomputer. The structure and principles of hardware and the flow chart of software are described in detail.

Simulating nailfold capillaroscopy sequences to evaluate algorithms for blood flow estimation.

PubMed

Tresadern, P A; Berks, M; Murray, A K; Dinsdale, G; Taylor, C J; Herrick, A L

2013-01-01

The effects of systemic sclerosis (SSc)--a disease of the connective tissue causing blood flow problems that can require amputation of the fingers--can be observed indirectly by imaging the capillaries at the nailfold, though taking quantitative measures such as blood flow to diagnose the disease and monitor its progression is not easy. Optical flow algorithms may be applied, though without ground truth (i.e. known blood flow) it is hard to evaluate their accuracy. We propose an image model that generates realistic capillaroscopy videos with known flow, and use this model to quantify the effect of flow rate, cell density and contrast (among others) on estimated flow. This resource will help researchers to design systems that are robust under real-world conditions.

Workspace analysis and design improvement of a carotid flow measurement system.

PubMed

Carbone, G; Nakadate, R; Solis, J; Ceccarelli, M; Takanishi, A; Minagawa, E; Sugawara, M; Niki, K

2010-11-01

Heart and cerebrovascular diseases such as arteriosclerosis and myocardial ischemia dysfunction are currently among the main causes of death in developed countries. Recently, wave intensity (WI), which is an index used to obtain the force of cardiac contraction, has been investigated as a method for early-stage diagnosis of the above-mentioned diseases. Nevertheless, experimental tests have proven that the manual measurements of WI by means of commercial ultrasonic diagnostic systems require too much time and can be affected by the operator's skills. For this purpose, the introduction of robotic-assisted technology has advantages in terms of repetitiveness and accuracy of the measurement procedure. Therefore, at Waseda University, the development of a carotid blood flow measurement system has been proposed to support doctors while using ultrasound diagnostic equipment to measure the WI. This robotic system is composed of a serial robot with a wrist having a six-degree-of-freedom (6-DOF) parallel mechanism. The main focus is to obtain a suitable workspace performance of the 6-DOF parallel mechanism wrist. In this paper, a workspace analysis is carried out on a wrist prototype built for the Waseda-Tokyo Women's Medical Aloka Blood Flow Measurement System No.1 Refined (WTA-1R). Then, mechanical design enhancements are proposed and validated to provide a suitable workspace performance both as reachable workspace and dexterity, and a refined prototype WTA-1RII has been built.

Measurements and calculations of water velocity, momentum flux, and related flow parameters obtaned from single-phase water integral acceptance tests of the PKL instrumented spool pieces

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

Stein, W.

The operation of the emergency core cooling system and its related steam-binding problems in pressurized water reactors is the subject of a cooperative study by the United States, Germany, and Japan. Lawrence Livermore Laboratory and EG and G, Inc., San Ramon Operations, are responsible for the design, hardware, and software of the 80.8-mm and 113-mm spool piece measurement systems for the German Primarkreislauf (PKL) Test Facility at Kraftwerk Union in Erlangen, West Germany. This work was done for the US Nuclear Regulatory Commission, Division of Reactor Safety Research, under its 3-D Technical Support and Instrumentation Program. Four instrumented spools capablemore » of measuring individual phase parameters in two-phase flows were constructed. Each spool contains a flow turbine, drag screen, three-beam densitometer, and pressure and temperature probes. A computerized data acquisition system is also provided to store and analyze data from the four spools. The four spools were shipped to the PKL Test Facility in West Germany for acceptance testing in a water-flow loop. Spool measurements of velocity and momentum flux were compared to the values obtained from an orifice meter installed in the loop piping system. The turbine flowmeter velocity data for all tests were within allowable tolerances. Drag screen momentum flux measurements were also within tolerance with the exception of a few points.« less

Flow cells for bioanalytical and bioprocess applications with optimized dynamic response and flow characteristics

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

Lancaster, V.R.; Modlin, D.N.

1994-12-31

In this study, the authors present a method for design and characterization of flow cells developed for minimum flow volume and optimal dynamic response with a given central observation area. The dynamic response of a circular shaped dual ported flow cell was compared to that obtained from a flow cell whose optimized shape was determined using this method. In the optimized flow cell design, the flow rate at the nominal operating pressure increased by 50% whereas the flow cell volume was reduced by 70%. In addition, the dynamic response of the new flow cell was found to be 200% fastermore » than the circular flow cell. The fluid dynamic analysis included simple graphical techniques utilizing free stream vorticity functions and Hagen-Poiseuille relationships. The flow cell dynamic response was measured using a fluorescence detection system. The fluoresce in emission from a 400{micro}m spot located at the exit port was measured as a function of time after switching the input to the flow cell between fluorescent and non-fluorescent solutions. Analysis of results revealed the system could be reasonably characterized as a first order dynamic system. Although some evidence of second order behavior was also observed, it is reasonable to assume that a first order model will provide adequate predictive capability for many real world applications. Given a set of flow cell requirements, the methods presented in this study can be used to design and characterize flow cells with lower reagent consumption and reduced purging times. These improvements can be readily translated into reduced process times and/or lower usage of high cost reagents.« less

Invited article: Time accurate mass flow measurements of solid-fueled systems.

PubMed

Olliges, Jordan D; Lilly, Taylor C; Joslyn, Thomas B; Ketsdever, Andrew D

2008-10-01

A novel diagnostic method is described that utilizes a thrust stand mass balance (TSMB) to directly measure time-accurate mass flow from a solid-fuel thruster. The accuracy of the TSMB mass flow measurement technique was demonstrated in three ways including the use of an idealized numerical simulation, verifying a fluid mass calibration with high-speed digital photography, and by measuring mass loss in more than 30 hybrid rocket motor firings. Dynamic response of the mass balance was assessed through weight calibration and used to derive spring, damping, and mass moment of inertia coefficients for the TSMB. These dynamic coefficients were used to determine the mass flow rate and total mass loss within an acrylic and gaseous oxygen hybrid rocket motor firing. Intentional variations in the oxygen flow rate resulted in corresponding variations in the total propellant mass flow as expected. The TSMB was optimized to determine mass losses of up to 2.5 g and measured total mass loss to within 2.5% of that calculated by a NIST-calibrated digital scale. Using this method, a mass flow resolution of 0.0011 g/s or 2% of the average mass flow in this study has been achieved.

Invited Article: Time accurate mass flow measurements of solid-fueled systems

NASA Astrophysics Data System (ADS)

Olliges, Jordan D.; Lilly, Taylor C.; Joslyn, Thomas B.; Ketsdever, Andrew D.

2008-10-01

A novel diagnostic method is described that utilizes a thrust stand mass balance (TSMB) to directly measure time-accurate mass flow from a solid-fuel thruster. The accuracy of the TSMB mass flow measurement technique was demonstrated in three ways including the use of an idealized numerical simulation, verifying a fluid mass calibration with high-speed digital photography, and by measuring mass loss in more than 30 hybrid rocket motor firings. Dynamic response of the mass balance was assessed through weight calibration and used to derive spring, damping, and mass moment of inertia coefficients for the TSMB. These dynamic coefficients were used to determine the mass flow rate and total mass loss within an acrylic and gaseous oxygen hybrid rocket motor firing. Intentional variations in the oxygen flow rate resulted in corresponding variations in the total propellant mass flow as expected. The TSMB was optimized to determine mass losses of up to 2.5 g and measured total mass loss to within 2.5% of that calculated by a NIST-calibrated digital scale. Using this method, a mass flow resolution of 0.0011 g/s or 2% of the average mass flow in this study has been achieved.

Investigation of the jet-wake flow of a highly loaded centrifugal compressor impeller

NASA Technical Reports Server (NTRS)

Eckardt, D.

1978-01-01

Investigations, aimed at developing a better understanding of the complex flow field in high performance centrifugal compressors were performed. Newly developed measuring techniques for unsteady static and total pressures as well as flow directions, and a digital data analysis system for fluctuating signals were thoroughly tested. The loss-affected mixing process of the distorted impeller discharge flow was investigated in detail, in the absolute and relative system, at impeller tip speeds up to 380 m/s. A theoretical analysis proved good coincidence of the test results with the DEAN-SENOO theory, which was extended to compressible flows.

Fluid Flow and Solidification Under Combined Action of Magnetic Fields and Microgravity

NASA Technical Reports Server (NTRS)

Li, B. Q.; Shu, Y.; Li, K.; deGroh, H. C.

2002-01-01

Mathematical models, both 2-D and 3-D, are developed to represent g-jitter induced fluid flows and their effects on solidification under combined action of magnetic fields and microgravity. The numerical model development is based on the finite element solution of governing equations describing the transient g-jitter driven fluid flows, heat transfer and solutal transport during crystal growth with and without an applied magnetic field in space vehicles. To validate the model predictions, a ground-based g-jitter simulator is developed using the oscillating wall temperatures where timely oscillating fluid flows are measured using a laser PIV system. The measurements are compared well with numerical results obtained from the numerical models. Results show that a combined action derived from magnetic damping and microgravity can be an effective means to control the melt flow and solutal transport in space single crystal growth systems.

Design and Implementation of Automatic Air Flow Rate Control System

NASA Astrophysics Data System (ADS)

Akbar, A.; Saputra, C.; Munir, M. M.; Khairurrijal

2016-08-01

Venturimeter is an apparatus that can be used to measure the air flow rate. In this experiment we designed a venturimeter which equipped with a valve that is used to control the air flow rate. The difference of pressure between the cross sections was measured with the differential pressure sensor GA 100-015WD which can calculate the difference of pressures from 0 to 3737.33 Pa. A 42M048C Z36 stepper motor was used to control the valve. The precision of this motor rotation is about 0.15 °. A Graphical User Interface (GUI) was developed to monitor and set the value of flow rate then an 8-bit microcontroller was used to process the control system In this experiment- the venturimeter has been examined to get the optimal parameter of controller. The results show that the controller can set the stable output air flow rate.

Aeroacoustic Characteristics of Model Jet Test Facility Flow Conditioners

NASA Technical Reports Server (NTRS)

Kinzie, Kevin W.; Henderson, Brenda S.; Haskin, Harry H.

2005-01-01

An experimental investigation of flow conditioning devices used to suppress internal rig noise in high speed, high temperature experimental jet facilities is discussed. The aerodynamic and acoustic characteristics of a number of devices including pressure loss and extraneous noise generation are measured. Both aerodynamic and acoustic characteristics are strongly dependent on the porosity of the flow conditioner and the closure ratio of the duct system. For unchoked flow conditioners, the pressure loss follows conventional incompressible flow models. However, for choked flow conditioners, a compressible flow model where the duct and flow conditioner system is modeled as a convergent-divergent nozzle can be used to estimate pressure loss. Choked flow conditioners generate significantly more noise than unchoked conditioners. In addition, flow conditioners with small hole diameters or sintered metal felt material generate less self-noise noise compared to flow conditioners with larger holes.

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1989-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1990-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Review: Regional land subsidence accompanying groundwater extraction

USGS Publications Warehouse

Galloway, Devin L.; Burbey, Thomas J.

2011-01-01

The extraction of groundwater can generate land subsidence by causing the compaction of susceptible aquifer systems, typically unconsolidated alluvial or basin-fill aquifer systems comprising aquifers and aquitards. Various ground-based and remotely sensed methods are used to measure and map subsidence. Many areas of subsidence caused by groundwater pumping have been identified and monitored, and corrective measures to slow or halt subsidence have been devised. Two principal means are used to mitigate subsidence caused by groundwater withdrawal—reduction of groundwater withdrawal, and artificial recharge. Analysis and simulation of aquifer-system compaction follow from the basic relations between head, stress, compressibility, and groundwater flow and are addressed primarily using two approaches—one based on conventional groundwater flow theory and one based on linear poroelasticity theory. Research and development to improve the assessment and analysis of aquifer-system compaction, the accompanying subsidence and potential ground ruptures are needed in the topic areas of the hydromechanical behavior of aquitards, the role of horizontal deformation, the application of differential synthetic aperture radar interferometry, and the regional-scale simulation of coupled groundwater flow and aquifer-system deformation to support resource management and hazard mitigation measures.

The Dynamics of Flow and Three-dimensional Motion Around a Morphologically Complex Aquatic Plant

NASA Astrophysics Data System (ADS)

Boothroyd, R.; Hardy, R. J.; Warburton, J.; Marjoribanks, T.

2016-12-01

Aquatic vegetation has a significant impact on the hydraulic functioning of river systems. The morphology of an individual plant can influence the mean and turbulent properties of the flow, and the plant posture reconfigures to minimise drag. We report findings from a flume and numerical experiment investigating the dynamics of motion and three-dimensional flow around an isolated Hebe odora plant over a range of flow conditions. In the flume experiment, a high definition video camera recorded plant motion dynamics and three-dimensional velocity profiles were measured using an acoustic Doppler velocimeter. By producing a binary image of the plant in each frame, the plant dynamics can be quantified. Zones of greatest plant motion are on the upper and leeward sides of the plant. With increasing flow the plant is compressed and deflected downwards by up to 18% of the unstressed height. Plant tip motions are tracked and shown to lengthen with increasing flow, transitioning from horizontally dominated to vertically dominated motion. The plant acts as a porous blockage to flow, producing spatially heterogeneous downstream velocity fields with the measured wake length decreasing by 20% with increasing flow. These measurements are then used as boundary conditions and to validate a computational fluid dynamics (CFD) model. By explicitly accounting for the time-averaged plant posture, good agreement is found between flume measurements and model predictions. The flow structures demonstrate characteristics of a junction vortex system, with plant shear layer turbulence dominated by Kelvin-Helmholtz and Görtler-type vortices generated through shear instability. With increasing flow, drag coefficients decrease by up to 8%, from 1.45 to 1.34. This is equivalent to a change in the Manning's n term from 0.086 to 0.078.

Design and Flight Evaluation of a New Force-Based Flow Angle Probe

NASA Technical Reports Server (NTRS)

Corda, Stephen; Vachon, Michael Jacob

2006-01-01

A novel force-based flow angle probe was designed and flight tested on the NASA F-15B Research Testbed aircraft at NASA Dryden Flight Research Center. The prototype flow angle probe is a small, aerodynamic fin that has no moving parts. Forces on the prototype flow angle probe are measured with strain gages and correlated with the local flow angle. The flow angle probe may provide greater simplicity, greater robustness, and better access to flow measurements in confined areas relative to conventional moving vane-type flow angle probes. Flight test data were obtained at subsonic, transonic, and supersonic Mach numbers to a maximum of Mach 1.70. Flight conditions included takeoff, landing, straight and level flight, flight at higher aircraft angles of attack, and flight at elevated g-loadings. Flight test maneuvers included angle-of-attack and angle-of-sideslip sweeps. The flow angle probe-derived flow angles are compared with those obtained with a conventional moving vane probe. The flight tests validated the feasibility of a force-based flow angle measurement system.

ICIASF '85 - International Congress on Instrumentation in Aerospace Simulation Facilities, 11th, Stanford University, CA, August 26-28, 1985, Record

NASA Technical Reports Server (NTRS)

1985-01-01

Developments related to laser Doppler velocimetry are discussed, taking into account a three-component dual beam laser-Doppler-anemometer to be operated in large wind tunnels, a new optical system for three-dimensional laser-Doppler-anemometry using an argon-ion and a dye laser, and a two-component laser Doppler velocimeter by switching fringe orientation. Other topics studied are concerned with facilities, instrumentation, control, hot wire/thin film measurements, optical diagnostic techniques, signal and data processing, facilities and adaptive wall test sections, data acquisition and processing, ballistic instrument systems, dynamic testing and material deformation measurements, optical flow measurements, test techniques, force measurement systems, and holography. Attention is given to nonlinear calibration of integral wind tunnel balances, a microcomputer system for real time digitized image compression, and two phase flow diagnostics in propulsion systems.

Laser-Raman/Rayleigh Flow Diagnostic Techniques Applied to Subsonic Flow

DTIC Science & Technology

1980-10-01

the problem of interpreting test results. Advances in electronics and laser technology have made it possible to perform measurements (which formerly...will increase with increasing gas density. It was the latter quality that made the prospect for successful subsonic flow-field measurements very...elements in the optical system were made of fused silica. An aperture was located at the entrance slit of the spectrometer and adjusted so that a 0.25-in

Evaluation of Fuel Character Effects on J79 Engine Combustion System

DTIC Science & Technology

1979-06-01

A. Overall Engine Description The J79 engine is a lightweight, high-thrust, axial - flow turbojet engine with variable afterburner thrust. This engine...thimbles are arranged to provide flow patterns for flame stabilization in the primary zone and mixing and turbine inlet temperature profile control at...measured with stainard )S𔃾Z orifices- Fuel flow races uere measured with calibrated turbine flotaMcers corrected for the density aan viscosity of each

Exact Recovery of Chaotic Systems from Highly Corrupted Data

DTIC Science & Technology

2016-08-01

dimension to reconstruct a state space which preserves the topological properties of the original system. In [CM87, RS92], the authors use the singular...in high dimensional nonlinear functional spaces [Spr94, SL00, LCC04]. In this work, we bring together connections between compressed sensing, splitting... compact , connected attractor Λ and the flow admits a unique so-called “physical" measure µ with supp(µ) = Λ. An invariant probability measure µ for a flow

A wireless monitoring system for Hydrocephalus shunts.

PubMed

Narayanaswamy, A; Nourani, M; Tamil, L; Bianco, S

2015-08-01

Patients with Hydrocephalus are usually treated by diverting the excess Cerebrospinal Fluid (CSF) to other parts of the body using shunts. More than 40 percentage of shunts implanted fail within the first two years. Obstruction in the shunts is one of the major causes of failure (45 percent) and the detection of obstruction reduces the complexity of the revision surgery. This paper describes a proposed wireless monitoring system for clog detection and flow measurement in shunts. A prototype was built using multiple pressure sensors along the shunt catheters for sensing the location of clog and flow rate. Regular monitoring of flow rates can be used to adjust the valve in the shunt to prevent over drainage or under drainage of CSF. The accuracy of the flow measurement is more than 90 percent.

Lingual, splanchnic, and systemic hemodynamic and carbon dioxide tension changes during endotoxic shock and resuscitation.

PubMed

Guzman, Jorge A; Dikin, Mathew S; Kruse, James A

2005-01-01

Sublingual and intestinal mucosal blood flow and Pco(2) were studied in a canine model of endotoxin-induced circulatory shock and resuscitation. Sublingual Pco(2) (Ps(CO(2))) was measured by using a novel fluorescent optrode-based technique and compared with lingual measurements obtained by using a Stowe-Severinghaus electrode [lingual Pco(2) (Pl(CO(2)))]. Endotoxin caused parallel changes in cardiac output, and in portal, intestinal mucosal, and sublingual blood flow (Q(s)). Different blood flow patterns were observed during resuscitation: intestinal mucosal blood flow returned to near baseline levels postfluid resuscitation and decreased by 21% after vasopressor resuscitation, whereas Q(s) rose to twice that of the preshock level and was maintained throughout the resuscitation period. Electrochemical and fluorescent Pco(2) measurements showed similar changes throughout the experiments. The shock-induced increases in Ps(CO(2)) and Pl(CO(2)) were nearly reversed after fluid resuscitation, despite persistent systemic arterial hypotension. Vasopressor administration induced a rebound of Ps(CO(2)) and Pl(CO(2)) to shock levels, despite higher cardiac output and Q(s), possibly due to blood flow redistribution and shunting. Changes in Pl(CO(2)) and Ps(CO(2)) paralleled gastric and intestinal Pco(2) changes during shock but not during resuscitation. We found that the lingual, splanchnic, and systemic circulations follow a similar pattern of blood flow variations in response to endotoxin shock, although discrepancies were observed during resuscitation. Restoration of systemic, splanchnic, and lingual perfusion can be accompanied by persistent tissue hypercarbia, mainly lingual and intestinal, more so when a vasopressor agent is used to normalize systemic hemodynamic variables.

TheClinical Research Tool: a high-performance microdialysis-based system for reliably measuring interstitial fluid glucose concentration.

PubMed

Ocvirk, Gregor; Hajnsek, Martin; Gillen, Ralph; Guenther, Arnfried; Hochmuth, Gernot; Kamecke, Ulrike; Koelker, Karl-Heinz; Kraemer, Peter; Obermaier, Karin; Reinheimer, Cornelia; Jendrike, Nina; Freckmann, Guido

2009-05-01

A novel microdialysis-based continuous glucose monitoring system, the so-called Clinical Research Tool (CRT), is presented. The CRT was designed exclusively for investigational use to offer high analytical accuracy and reliability. The CRT was built to avoid signal artifacts due to catheter clogging, flow obstruction by air bubbles, and flow variation caused by inconstant pumping. For differentiation between physiological events and system artifacts, the sensor current, counter electrode and polarization voltage, battery voltage, sensor temperature, and flow rate are recorded at a rate of 1 Hz. In vitro characterization with buffered glucose solutions (c(glucose) = 0 - 26 x 10(-3) mol liter(-1)) over 120 h yielded a mean absolute relative error (MARE) of 2.9 +/- 0.9% and a recorded mean flow rate of 330 +/- 48 nl/min with periodic flow rate variation amounting to 24 +/- 7%. The first 120 h in vivo testing was conducted with five type 1 diabetes subjects wearing two systems each. A mean flow rate of 350 +/- 59 nl/min and a periodic variation of 22 +/- 6% were recorded. Utilizing 3 blood glucose measurements per day and a physical lag time of 1980 s, retrospective calibration of the 10 in vivo experiments yielded a MARE value of 12.4 +/- 5.7. Clarke error grid analysis resulted in 81.0%, 16.6%, 0.8%, 1.6%, and 0% in regions A, B, C, D, and E, respectively. The CRT demonstrates exceptional reliability of system operation and very good measurement performance. The ability to differentiate between artifacts and physiological effects suggests the use of the CRT as a reference tool in clinical investigations. 2009 Diabetes Technology Society.

The Clinical Research Tool: A High-Performance Microdialysis-Based System for Reliably Measuring Interstitial Fluid Glucose Concentration

PubMed Central

Ocvirk, Gregor; Hajnsek, Martin; Gillen, Ralph; Guenther, Arnfried; Hochmuth, Gernot; Kamecke, Ulrike; Koelker, Karl-Heinz; Kraemer, Peter; Obermaier, Karin; Reinheimer, Cornelia; Jendrike, Nina; Freckmann, Guido

2009-01-01

Background A novel microdialysis-based continuous glucose monitoring system, the so-called Clinical Research Tool (CRT), is presented. The CRT was designed exclusively for investigational use to offer high analytical accuracy and reliability. The CRT was built to avoid signal artifacts due to catheter clogging, flow obstruction by air bubbles, and flow variation caused by inconstant pumping. For differentiation between physiological events and system artifacts, the sensor current, counter electrode and polarization voltage, battery voltage, sensor temperature, and flow rate are recorded at a rate of 1 Hz. Method In vitro characterization with buffered glucose solutions (cglucose = 0 - 26 × 10-3 mol liter-1) over 120 h yielded a mean absolute relative error (MARE) of 2.9 ± 0.9% and a recorded mean flow rate of 330 ± 48 nl/min with periodic flow rate variation amounting to 24 ± 7%. The first 120 h in vivo testing was conducted with five type 1 diabetes subjects wearing two systems each. A mean flow rate of 350 ± 59 nl/min and a periodic variation of 22 ± 6% were recorded. Results Utilizing 3 blood glucose measurements per day and a physical lag time of 1980 s, retrospective calibration of the 10 in vivo experiments yielded a MARE value of 12.4 ± 5.7. Clarke error grid analysis resulted in 81.0%, 16.6%, 0.8%, 1.6%, and 0% in regions A, B, C, D, and E, respectively. Conclusion The CRT demonstrates exceptional reliability of system operation and very good measurement performance. The ability to differentiate between artifacts and physiological effects suggests the use of the CRT as a reference tool in clinical investigations. PMID:20144284

Liquid Bismuth Feed System for Electric Propulsion

NASA Technical Reports Server (NTRS)

Markusic, T. E.; Polzin, K. A.; Stanojev, B. J.

2006-01-01

Operation of Hall thrusters with bismuth propellant has been shown to be a promising path toward high-power, high-performance, long-lifetime electric propulsion for spaceflight missions. For example, the VHITAL project aims td accurately, experimentally assess the performance characteristics of 10 kW-class bismuth-fed Hall thrusters - in order to validate earlier results and resuscitate a promising technology that has been relatively dormant for about two decades. A critical element of these tests will be the precise metering of propellant to the thruster, since performance cannot be accurately assessed without an accurate accounting of mass flow rate. Earlier work used a pre/post-test propellant weighing scheme that did not provide any real-time measurement of mass flow rate while the thruster was firing, and makes subsequent performance calculations difficult. The motivation of the present work was to develop a precision liquid bismuth Propellant Management System (PMS) that provides real-time propellant mass flow rate measurement and control, enabling accurate thruster performance measurements. Additionally, our approach emphasizes the development of new liquid metal flow control components and, hence, will establish a basis for the future development of components for application in spaceflight. The design of various critical components in a bismuth PMS are described - reservoir, electromagnetic pump, hotspot flow sensor, and automated control system. Particular emphasis is given to material selection and high-temperature sealing techniques. Open loop calibration test results are reported, which validate the systems capability to deliver bismuth at mass flow rates ranging from 10 to 100 mg/sec with an uncertainty of less than +/- 5%. Results of integrated vaporizer/liquid PMS tests demonstrate all of the necessary elements of a complete bismuth feed system for electric propulsion.

Association of HeartMate II left ventricular assist device flow estimate with thermodilution cardiac output.

PubMed

Hasin, Tal; Huebner, Marianne; Li, Zhuo; Brown, Daniel; Stulak, John M; Boilson, Barry A; Joyce, Lyle; Pereira, Naveen L; Kushwaha, Sudhir S; Park, Soon J

2014-01-01

Cardiac output (CO) assessment is important in treating patients with heart failure. Durable left ventricular assist devices (LVADs) provide essentially all CO. In currently used LVADs, estimated device flow is generated by a computerized algorithm. However, LVAD flow estimate may be inaccurate in tracking true CO. We correlated LVAD (HeartMate II) flow with thermodilution CO during postoperative care (day 2-10 after implant) in 81 patients (5,616 paired measurements). Left ventricular assist device flow and CO correlated with a low correlation coefficient (r = 0.42). Left ventricular assist device readings were lower than CO measurements by approximately 0.36 L/min, trending for larger difference with higher values. Left ventricular assist device flow measurements showed less temporal variability compared with CO. Grouping for simultaneous measured blood pressure (BP < 60, 60-70, 70-80, 80-90, and ≥90), the correlation of CO with LVAD flow differed (R = 0.42, 0.67, 0.48, 0.32, 0.32, respectively). Indicating better correlation when mean blood pressure is 60 to 70 mm Hg. Left ventricular assist device flow generally trends with measured CO, but large variability exists, hence flow measures should not be assumed to equal with CO. Clinicians should take into account variables such as high CO, BP, and opening of the aortic valve when interpreting LVAD flow readout. Direct flow sensors incorporated in the LVAD system may allow for better estimation.

Detection of Site-Specific Blood Flow Variation in Humans during Running by a Wearable Laser Doppler Flowmeter.

PubMed

Iwasaki, Wataru; Nogami, Hirofumi; Takeuchi, Satoshi; Furue, Masutaka; Higurashi, Eiji; Sawada, Renshi

2015-10-05

Wearable wireless physiological sensors are helpful for monitoring and maintaining human health. Blood flow contains abundant physiological information but it is hard to measure blood flow during exercise using conventional blood flowmeters because of their size, weight, and use of optic fibers. To resolve these disadvantages, we previously developed a micro integrated laser Doppler blood flowmeter using microelectromechanical systems technology. This micro blood flowmeter is wearable and capable of stable measurement signals even during movement. Therefore, we attempted to measure skin blood flow at the forehead, fingertip, and earlobe of seven young men while running as a pilot experiment to extend the utility of the micro blood flowmeter. We measured blood flow in each subject at velocities of 6, 8, and 10 km/h. We succeeded in obtaining stable measurements of blood flow, with few motion artifacts, using the micro blood flowmeter, and the pulse wave signal and motion artifacts were clearly separated by conducting frequency analysis. Furthermore, the results showed that the extent of the changes in blood flow depended on the intensity of exercise as well as previous work with an ergometer. Thus, we demonstrated the capability of this wearable blood flow sensor for measurement during exercise.

Dual-RiverSonde measurements of two-dimensional river flow patterns

USGS Publications Warehouse

Teague, C.C.; Barrick, D.E.; Lilleboe, P.M.; Cheng, R.T.; Stumpner, P.; Burau, J.R.

2008-01-01

Two-dimensional river flow patterns have been measured using a pair of RiverSondes in two experiments in the Sacramento-San Joaquin River Delta system of central California during April and October 2007. An experiment was conducted at Walnut Grove, California in order to explore the use of dual RiverSondes to measure flow patterns at a location which is important in the study of juvenile fish migration. The data available during the first experiment were limited by low wind, so a second experiment was conducted at Threemile Slough where wind conditions and surface turbulence historically have resulted in abundant data. Both experiments included ADCP near-surface velocity measurements from either manned or unmanned boats. Both experiments showed good comparisons between the RiverSonde and ADCP measurements. The flow conditions at both locations are dominated by tidal effects, with partial flow reversal at Walnut Grove and complete flow reversal at Threemile Slough. Both systems showed complex flow patterns during the flow reversals. Quantitative comparisons between the RiverSondes and an ADCP on a manned boat at Walnut Grove showed mean differences of 4.5 cm/s in the u (eastward) and 7.6 cm/s in the v (northward) components, and RMS differences of 14.7 cm/s in the u component and 21.0 cm/s in the v component. Quantitative comparisons between the RiverSondes and ADCPs on autonomous survey vessels at Threemile Slough showed mean differences of 0.007 cm/s in the u component and 0.5 cm/s in the v component, and RMS differences of 7.9 cm/s in the u component and 13.5 cm/s in the v component after obvious outliers were removed. ?? 2008 IEEE.

Microfluidic diffusion diluter: bulging of PDMS microchannels under pressure-driven flow

NASA Astrophysics Data System (ADS)

Holden, Matthew A.; Kumar, Saurabh; Beskok, Ali; Cremer, Paul S.

2003-05-01

The bulging of microfluidic systems during pressure-driven flow is potentially a major consideration for polydimethylsiloxane (PDMS)-based devices. Microchannel cross-sectional areas can change drastically as a function of flow rate and downstream microchannel position. Such geometrical flexibility leads to difficulties in predicting convective/diffusive transport for these systems. We have previously introduced a non-dimensional parameter, kappa, for characterizing convection and diffusion behavior for pressure-driven flow in rigid all-glass systems. This paper describes a modification of that concept for application to non-rigid systems, which is accomplished by incorporating an experimental step to account for the bulging in PDMS/glass microsystems. Specifically, an experimental measurement of channel height by fluorescence microscopy is combined with the aforementioned theory to characterize convective/diffusive behavior at a single location in the device. This allowed the parameter kappa to be determined at that point and applied to predict fluid flow in the subsequent portion of the PDMS microsystem. This procedure was applied to a PDMS/glass microfluidic diffusion dilution (muDD) device designed for generating concentration gradients. Theoretically predicted and experimentally measured distributions of concentrations within the microsystem matched well.

Real-time image processing for particle tracking velocimetry

NASA Astrophysics Data System (ADS)

Kreizer, Mark; Ratner, David; Liberzon, Alex

2010-01-01

We present a novel high-speed particle tracking velocimetry (PTV) experimental system. Its novelty is due to the FPGA-based, real-time image processing "on camera". Instead of an image, the camera transfers to the computer using a network card, only the relevant information of the identified flow tracers. Therefore, the system is ideal for the remote particle tracking systems in research and industrial applications, while the camera can be controlled and data can be transferred over any high-bandwidth network. We present the hardware and the open source software aspects of the PTV experiments. The tracking results of the new experimental system has been compared to the flow visualization and particle image velocimetry measurements. The canonical flow in the central cross section of a a cubic cavity (1:1:1 aspect ratio) in our lid-driven cavity apparatus is used for validation purposes. The downstream secondary eddy (DSE) is the sensitive portion of this flow and its size was measured with increasing Reynolds number (via increasing belt velocity). The size of DSE estimated from the flow visualization, PIV and compressed PTV is shown to agree within the experimental uncertainty of the methods applied.

Method and apparatus for acoustically monitoring the flow of suspended solid particulate matter

DOEpatents

Roach, Paul D.; Raptis, Apostolos C.

1982-01-01

A method and apparatus for monitoring char flow in a coal gasifier system cludes flow monitor circuits which measure acoustic attenuation caused by the presence of char in a char line and provide a char flow/no flow indication and an indication of relative char density. The flow monitor circuits compute the ratio of signals in two frequency bands, a first frequency band representative of background noise, and a second higher frequency band in which background noise is attenuated by the presence of char. Since the second frequency band contains higher frequencies, the ratio can be used to provide a flow/no flow indication. The second band can also be selected so that attenuation is monotonically related to particle concentration, providing a quantitative measure of char concentration.

Modification of a compressor performance test bench for liquid slugging observation in refrigeration compressors

NASA Astrophysics Data System (ADS)

Ola, Max; Thomas, Christiane; Hesse, Ullrich

2017-08-01

Compressor performance test procedures are defined by the standard DIN EN 13771, wherein a variety of possible calorimeter and flow rate measurement methods are suggested. One option is the selection of two independent measurement methods. The accuracies of both selected measurement methods are essential. The second option requires only one method. However the measurement accuracy of the used device has to be verified and recalibrated on a regular basis. The compressor performance test facility at the Technische Universitaet Dresden uses a calibrated flow measurement sensor, a hot gas bypass and a mixed flow heat exchanger. The test bench can easily be modified for tests of various compressor types at different operating ranges and with various refrigerants. In addition, the modified test setup enables the investigation of long term liquid slug and its effects on the compressor. The modification comprises observational components, adjustments of the control system, safety measures and a customized oil recirculation system for compressors which do not contain an integrated oil sump or oil level regulation system. This paper describes the setup of the test bench, its functional principle, the key modifications, first test results and an evaluation of the energy balance.

Modifications to the nozzle test chamber to extend nozzle static-test capability

NASA Technical Reports Server (NTRS)

Keyes, J. W.

1985-01-01

The nozzle test chamber was modified to provide a high-pressure-ratio nozzle static-test capability. Experiments were conducted to determine the range of the ratio of nozzle total pressure to chamber pressure and to make direct nozzle thrust measurements using a three-component strain-gage force balance. Pressure ratios from 3 to 285 were measured with several axisymmetric nozzles at a nozzle total pressure of 15 to 190 psia. Devices for measuring system mass flow were calibrated using standard axisymmetric convergent choked nozzles. System mass-flow rates up to 10 lbm/sec are measured. The measured thrust results of these nozzles are in good agreement with one-dimensional theoretical predictions for convergent nozzles.

Systems and methods for thermal imaging technique for measuring mixing of fluids

DOEpatents

Booten, Charles; Tomerlin, Jeff; Winkler, Jon

2016-06-14

Systems and methods for thermal imaging for measuring mixing of fluids are provided. In one embodiment, a method for measuring mixing of gaseous fluids using thermal imaging comprises: positioning a thermal test medium parallel to a direction gaseous fluid flow from an outlet vent of a momentum source, wherein when the source is operating, the fluid flows across a surface of the medium; obtaining an ambient temperature value from a baseline thermal image of the surface; obtaining at least one operational thermal image of the surface when the fluid is flowing from the outlet vent across the surface, wherein the fluid has a temperature different than the ambient temperature; and calculating at least one temperature-difference fraction associated with at least a first position on the surface based on a difference between temperature measurements obtained from the at least one operational thermal image and the ambient temperature value.

Zonal Flow Velocimetry in Spherical Couette Flow using Acoustic Modes

NASA Astrophysics Data System (ADS)

Adams, Matthew M.; Mautino, Anthony R.; Stone, Douglas R.; Triana, Santiago A.; Lekic, Vedran; Lathrop, Daniel P.

2015-11-01

We present studies of spherical Couette flows using the technique of acoustic mode Doppler velocimetry. This technique uses rotational splittings of acoustic modes to infer the azimuthal velocity profile of a rotating flow, and is of special interest in experiments where direct flow visualization is impractical. The primary experimental system consists of a 60 cm diameter outer spherical shell concentric with a 20 cm diameter sphere, with air or nitrogen gas serving as the working fluid. The geometry of the system approximates that of the Earth's core, making these studies geophysically relevant. A turbulent shear flow is established in the system by rotating the inner sphere and outer shell at different rates. Acoustic modes of the fluid volume are excited using a speaker and measured via microphones, allowingdetermination of rotational splittings. Preliminary results comparing observed splittings with those predicted by theory are presented. While the majority of these studies were performed in the 60 cm diameter device using nitrogen gas, some work has also been done looking at acoustic modes in the 3 m diameter liquid sodium spherical Couette experiment. Prospects for measuring zonal velocity profiles in a wide variety of experiments are discussed.

Load flow and state estimation algorithms for three-phase unbalanced power distribution systems

NASA Astrophysics Data System (ADS)

Madvesh, Chiranjeevi

Distribution load flow and state estimation are two important functions in distribution energy management systems (DEMS) and advanced distribution automation (ADA) systems. Distribution load flow analysis is a tool which helps to analyze the status of a power distribution system under steady-state operating conditions. In this research, an effective and comprehensive load flow algorithm is developed to extensively incorporate the distribution system components. Distribution system state estimation is a mathematical procedure which aims to estimate the operating states of a power distribution system by utilizing the information collected from available measurement devices in real-time. An efficient and computationally effective state estimation algorithm adapting the weighted-least-squares (WLS) method has been developed in this research. Both the developed algorithms are tested on different IEEE test-feeders and the results obtained are justified.

System and method for bidirectional flow and controlling fluid flow in a conduit

DOEpatents

Ortiz, Marcos German

1999-01-01

A system for measuring bidirectional flow, including backflow, of fluid in a conduit. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit.

Computational Aerodynamic Simulations of an 840 ft/sec Tip Speed Advanced Ducted Propulsor Fan System Model for Acoustic Methods Assessment and Development

NASA Technical Reports Server (NTRS)

Tweedt, Daniel L.

2014-01-01

Computational Aerodynamic simulations of an 840 ft/sec tip speed, Advanced Ducted Propulsor fan system were performed at five different operating points on the fan operating line, in order to provide detailed internal flow field information for use with fan acoustic prediction methods presently being developed, assessed and validated. The fan system is a sub-scale, lownoise research fan/nacelle model that has undergone extensive experimental testing in the 9- by 15- foot Low Speed Wind Tunnel at the NASA Glenn Research Center, resulting in quality, detailed aerodynamic and acoustic measurement data. Details of the fan geometry, the computational fluid dynamics methods, the computational grids, and various computational parameters relevant to the numerical simulations are discussed. Flow field results for three of the five operating conditions simulated are presented in order to provide a representative look at the computed solutions. Each of the five fan aerodynamic simulations involved the entire fan system, excluding a long core duct section downstream of the core inlet guide vane. As a result, only fan rotational speed and system bypass ratio, set by specifying static pressure downstream of the core inlet guide vane row, were adjusted in order to set the fan operating point, leading to operating points that lie on a fan operating line and making mass flow rate a fully dependent parameter. The resulting mass flow rates are in good agreement with measurement values. The computed blade row flow fields for all five fan operating points are, in general, aerodynamically healthy. Rotor blade and fan exit guide vane flow characteristics are good, including incidence and deviation angles, chordwise static pressure distributions, blade surface boundary layers, secondary flow structures, and blade wakes. Examination of the computed flow fields reveals no excessive boundary layer separations or related secondary-flow problems. A few spanwise comparisons between computational and measurement data in the bypass duct show that they are in good agreement, thus providing a partial validation of the computational results.

Time-Resolved PIV for Space-Time Correlations in Hot Jets

NASA Technical Reports Server (NTRS)

Wernet, Mark P.

2007-01-01

Temporally Resolved Particle Image Velocimetry (TR-PIV) is being used to characterize the decay of turbulence in jet flows a critical element for understanding the acoustic properties of the flow. A TR-PIV system, developed in-house at the NASA Glenn Research Center, is capable of acquiring planar PIV image frame pairs at up to 10 kHz. The data reported here were collected at Mach numbers of 0.5 and 0.9 and at temperature ratios of 0.89 and 1.76. The field of view of the TR-PIV system covered 6 nozzle diameters along the lip line of the 50.8 mm diameter jet. The cold flow data at Mach 0.5 were compared with hotwire anemometry measurements in order to validate the new TR-PIV technique. The axial turbulence profiles measured across the shear layer using TR-PIV were thinner than those measured using hotwire anemometry and remained centered along the nozzle lip line. The collected TR-PIV data illustrate the differences in the single point statistical flow properties of cold and hot jet flows. The planar, time-resolved velocity records were then used to compute two-point space-time correlations of the flow at the Mach 0.9 flow condition. The TR-PIV results show that there are differences in the convective velocity and growth rate of the turbulent structures between cold and hot flows at the same Mach number.

An in vitro test bench reproducing coronary blood flow signals.

PubMed

Chodzyński, Kamil Jerzy; Boudjeltia, Karim Zouaoui; Lalmand, Jacques; Aminian, Adel; Vanhamme, Luc; de Sousa, Daniel Ribeiro; Gremmo, Simone; Bricteux, Laurent; Renotte, Christine; Courbebaisse, Guy; Coussement, Grégory

2015-08-07

It is a known fact that blood flow pattern and more specifically the pulsatile time variation of shear stress on the vascular wall play a key role in atherogenesis. The paper presents the conception, the building and the control of a new in vitro test bench that mimics the pulsatile flows behavior based on in vivo measurements. An in vitro cardiovascular simulator is alimented with in vivo constraints upstream and provided with further post-processing analysis downstream in order to mimic the pulsatile in vivo blood flow quantities. This real-time controlled system is designed to perform real pulsatile in vivo blood flow signals to study endothelial cells' behavior under near physiological environment. The system is based on an internal model controller and a proportional-integral controller that controls a linear motor with customized piston pump, two proportional-integral controllers that control the mean flow rate and temperature of the medium. This configuration enables to mimic any resulting blood flow rate patterns between 40 and 700 ml/min. In order to feed the system with reliable periodic flow quantities in vivo measurements were performed. Data from five patients (1 female, 4 males; ages 44-63) were filtered and post-processed using the Newtonian Womersley's solution. These resulting flow signals were compared with 2D axisymmetric, numerical simulation using a Carreau non-Newtonian model to validate the approximation of a Newtonian behavior. This in vitro test bench reproduces the measured flow rate time evolution and the complexity of in vivo hemodynamic signals within the accuracy of the relative error below 5%. This post-processing method is compatible with any real complex in vivo signal and demonstrates the heterogeneity of pulsatile patterns in coronary arteries among of different patients. The comparison between analytical and numerical solution demonstrate the fair quality of the Newtonian Womersley's approximation. Therefore, Womersley's solution was used to calculate input flow rate for the in vitro test bench.

Method and apparatus for acoustically monitoring the flow of suspended solid particulate matter. [Patent application; monitoring char flow in coal gasifier

DOEpatents

Roach, P.D.; Raptis, A.C.

1980-11-24

A method and apparatus for monitoring char flow in a coal gasifier system includes flow monitor circuits which measure acoustic attenuation caused by the presence of char in a char line and provides a char flow/no flow indication and an indication of relative char density. The flow monitor circuits compute the ratio of signals in two frequency bands, a first frequency band representative of background noise, and a second higher frequency band in which background noise is attenuated by the presence of char. Since the second frequency band contains higher frequencies, the ratio can be used to provide a flow/no flow indication. The second band can also be selected so that attenuation is monotonically related to particle concentration, providing a quantitative measure of char concentration.

Flow and contaminant transport in an airliner cabin induced by a moving body: Model experiments and CFD predictions

NASA Astrophysics Data System (ADS)

Poussou, Stephane B.; Mazumdar, Sagnik; Plesniak, Michael W.; Sojka, Paul E.; Chen, Qingyan

2010-08-01

The effects of a moving human body on flow and contaminant transport inside an aircraft cabin were investigated. Experiments were performed in a one-tenth scale, water-based model. The flow field and contaminant transport were measured using the Particle Image Velocimetry (PIV) and Planar Laser-Induced Fluorescence (PLIF) techniques, respectively. Measurements were obtained with (ventilation case) and without (baseline case) the cabin environmental control system (ECS). The PIV measurements show strong intermittency in the instantaneous near-wake flow. A symmetric downwash flow was observed along the vertical centerline of the moving body in the baseline case. The evolution of this flow pattern is profoundly perturbed by the flow from the ECS. Furthermore, a contaminant originating from the moving body is observed to convect to higher vertical locations in the presence of ventilation. These experimental data were used to validate a Computational Fluid Dynamic (CFD) model. The CFD model can effectively capture the characteristic flow features and contaminant transport observed in the small-scale model.

Test stand for gas-discharge chamber of TEA CO2 lasers with pulse-periodical energy supply

NASA Astrophysics Data System (ADS)

Shorin, Vladimyr P.; Bystrov, N. D.; Zhuravlyov, O. A.; Nekrasov, V. V.

1997-05-01

Test stand for function optimization (incomposition of gas- dynamic circuit (GDC) of operating characteristics of full- size discharge chamber of flowing TEA carbon-dioxide lasers (power up to 100 kW) was created in Samara State Aerospace University (former Kuibyshev Aviation Institute). Test stand includes an inside-type GDC, low inductive generators of voltage pulses of preionization and main discharges, two-flow rate system of gas supply and noise immunity diagnostic system. Module construction of units of GDC, power supplies of preionization and main discharges allows to change configuration of stand's systems for providing given properties of gas flow and its energy supply. This test stand can also be used in servicing of laser system. The diagnostic system of this stand allows us to analyze energy properties of discharge by means of oscillographic measurements of voltage and current with following processing of discharges' volt- ampere characteristics by means of a computer; rate of non- stationary gas-dynamic disturbances in discharge gap of discharge chamber was measured by means of pulse holographic system (UlG-1M) with data processing of schliren- and interferogram (density fluctuation sensitivity approximately 10-2) and sensor measurement system of gas-dynamic shock and acoustics process with resonance frequency exceeding 100 kHz. Research results of process of plasma plate wave and channel structures interaction with mediums, including actuation non-stationary gas-dynamic flows, cavitation erosion of preionization electrodes' dielectric substructure, ancillary heating of channels by main volumetric discharge are presented as well.

Miniaturized flow injection analysis system

DOEpatents

Folta, J.A.

1997-07-01

A chemical analysis technique known as flow injection analysis is described, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38{times}25{times}3 mm, but can be designed for gas analysis and be substantially smaller in construction. 9 figs.

Small-volume, ultrahigh-vacuum-compatible high-pressure reaction cell for combined kinetic and in situ IR spectroscopic measurements on planar model catalysts

NASA Astrophysics Data System (ADS)

Zhao, Z.; Diemant, T.; Häring, T.; Rauscher, H.; Behm, R. J.

2005-12-01

We describe the design and performance of a high-pressure reaction cell for simultaneous kinetic and in situ infrared reflection (IR) spectroscopic measurements on model catalysts at elevated pressures, between 10-3 and 103mbars, which can be operated both as batch reactor and as flow reactor with defined gas flow. The cell is attached to an ultrahigh-vacuum (UHV) system, which is used for sample preparation and also contains facilities for sample characterization. Specific for this design is the combination of a small cell volume, which allows kinetic measurements with high sensitivity under batch or continuous flow conditions, the complete isolation of the cell from the UHV part during UHV measurements, continuous temperature control during both UHV and high-pressure operation, and rapid transfer between UHV and high-pressure stage. Gas dosing is performed by a designed gas-handling system, which allows operation as flow reactor with calibrated gas flows at adjustable pressures. To study the kinetics of reactions on the model catalysts, a quadrupole mass spectrometer is connected to the high-pressure cell. IR measurements are possible in situ by polarization-modulation infrared reflection-absorption spectroscopy, which also allows measurements at elevated pressures. The performance of the setup is demonstrated by test measurements on the kinetics for CO oxidation and the CO adsorption on a Au /TiO2/Ru(0001) model catalyst film at 1-50 mbar total pressure.

Broadband pulsed flow using piezoelectric microjets

NASA Astrophysics Data System (ADS)

Hogue, Joshua; Solomon, John; Hays, Michael; Alvi, Farrukh; Oates, William

2010-04-01

A piezohydraulic microjet design and experimental results are presented to demonstrate broadband active flow control for applications on various aircraft structures including impinging jets, rotor blades, cavity bays, etc. The microjet actuator includes a piezoelectric stack actuator and hydraulic circuit that is used to throttle a 400 μm diameter microjet using hydraulic amplification of the piezoelectric stack actuator. This system is shown to provide broadband pulsed flow actuation up to 800 Hz. Unsteady pressure measurements of the microjet's exit flow are coupled with high-speed phase imagery using micro-Schlieren techniques to quantify the flow field. These results are compared with in situ stack actuator displacements using strain gauge measurements.

Pulmonary arterial compliance: How and why should we measure it?

PubMed Central

Ghio, Stefano; Schirinzi, Sandra; Pica, Silvia

2015-01-01

The pulmonary circulation is a high-flow/low-pressure system, coupled with a flow generator chamber–the right ventricle–, which is relatively unable to tolerate increases in afterload. A right heart catheterization, using a fluid-filled, balloon-tipped Swan-Ganz catheter allows the measurement of all hemodynamic parameters characterizing the pulmonary circulation: the inflow pressure, an acceptable estimate the outflow pressure, and the pulmonary blood flow. However, the study of the pulmonary circulation as a continuous flow system is an oversimplification and a thorough evaluation of the pulmonary circulation requires a correct understanding of the load that the pulmonary vascular bed imposes on the right ventricle, which includes static and dynamic components. This is critical to assess the prognosis of patients with pulmonary hypertension or with heart failure. Pulmonary compliance is a measure of arterial distensibility and, either alone or in combination with pulmonary vascular resistance, gives clinicians the possibility of a good prognostic stratification of patients with heart failure or with pulmonary hypertension. The measurement of pulmonary arterial compliance should be included in the routine clinical evaluation of such patients. PMID:26779530

A review of mass and energy flow through a lava flow system: insights provided from a non-equilibrium perspective

NASA Astrophysics Data System (ADS)

Tarquini, Simone

2017-08-01

A simple formula relates lava discharge rate to the heat radiated per unit time from the surface of active lava flows (the "thermal proxy"). Although widely used, the physical basis of this proxy is still debated. In the present contribution, lava flows are approached as open, dissipative systems that, under favorable conditions, can attain a non-equilibrium stationary state. In this system framework, the onset, growth, and demise of lava flow units can be explained as a self-organization phenomenon characterized by a given temporal frequency defined by the average life span of active lava flow units. Here, I review empirical, physical, and experimental models designed to understand and link the flow of mass and energy through a lava flow system, as well as measurements and observations that support a "real-world" view. I set up two systems: active lava flow system (or ALFS) for flowing, fluid lava and a lava deposit system for solidified, cooling lava. The review highlights surprising similarities between lava flows and electric currents, which typically work under stationary conditions. An electric current propagates almost instantaneously through an existing circuit, following the Kirchhoff law (a least dissipation principle). Flowing lavas, in contrast, build up a slow-motion "lava circuit" over days, weeks, or months by following a gravity-driven path down the steepest slopes. Attainment of a steady-state condition is hampered (and the classic thermal proxy does not hold) if the supply stops before completion of the "lava circuit." Although gravity determines initial flow path and extension, the least dissipation principle means that subsequent evolution of mature portions of the active lava flow system is controlled by increasingly insulated conditions.

High-speed holocinematographic velocimeter for studying turbulent flow control physics

NASA Technical Reports Server (NTRS)

Weinstein, L. M.; Beeler, G. B.; Lindemann, A. M.

1985-01-01

Use of a dual view, high speed, holographic movie technique is examined for studying turbulent flow control physics. This approach, which eliminates some of the limitations of previous holographic techniques, is termed a holocinematographic velocimeter (HCV). The data from this system can be used to check theoretical turbulence modeling and numerical simulations, visualize and measure coherent structures in 'non-simple' turbulent flows, and examine the mechanisms operative in various turbulent control/drag reduction concepts. This system shows promise for giving the most complete experimental characterization of turbulent flows yet available.

Development of Cellular Absorptive Tracers (CATs) for a Quantitative Characterization of Microbial Mass in Flow Systems

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

Saripalli, Prasad; Brown, Christopher F.; Lindberg, Michael J.

We report on a new Cellular Absorptive Tracers (CATs) method, for a simple, non-destructive characterization of bacterial mass in flow systems. Results show that adsorption of a CAT molecule into the cellular mass results in its retardation during flow, which is a good, quantitative measure of the biomass quantity and distribution. No such methods are currently available for a quantitative characterization of cell mass.

Three dimensional LDV flow measurements and theoretical investigation in a radial inflow turbine scroll

NASA Technical Reports Server (NTRS)

Malak, Malak Fouad; Hamed, Awatef; Tabakoff, Widen

1990-01-01

A two-color LDV system was used in the measurement of three orthogonal velocity components at 758 points located throughout the scroll and the unvaned portion of the nozzle of a radial inflow turbine scroll. The cold flow experimental results are presented for the velocity field at the scroll tongue. In addition, a total pressure loss of 3.5 percent for the scroll is revealed from the velocity measurements combined with the static pressure readings. Moreover, the measurement of the three normal stresses of the turbulence has showed that the flow is anisotropic. Furthermore, the mean velocity components are compared with a numerical solution of the potential flow field using the finite element technique. The theoretical prediction of the exit flow angle variation agrees well with the experimental results. This variation leads to a higher scroll pattern factor which can be avoided by controlling the scroll cross sectional area distribution.

Pancreatic islet blood flow and its measurement

PubMed Central

Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

2016-01-01

Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

Simultaneous moisture content and mass flow measurements in wood chip flows using coupled dielectric and impact sensors

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

Pan, Pengmin; McDonald, Timothy; Fulton, John

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. Testsmore » 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. As a result, in situations where flows could not be impeded, however, the tomographic approach would likely be more useful.« less

Simultaneous moisture content and mass flow measurements in wood chip flows using coupled dielectric and impact sensors

DOE PAGES

Pan, Pengmin; McDonald, Timothy; Fulton, John; ...

2016-12-23

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. Testsmore » 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. As a result, in situations where flows could not be impeded, however, the tomographic approach would likely be more useful.« less

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

PubMed Central

Pan, Pengmin; McDonald, Timothy; Fulton, John; Via, Brian; Hung, John

2016-01-01

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. PMID:28025536

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

NASA Astrophysics Data System (ADS)

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.

Cerebrospinal fluid bulk flow is driven by the cardiac cycle

NASA Astrophysics Data System (ADS)

Tithof, Jeffrey; Mestre, Humberto; Thomas, John; Nedergaard, Maiken; Kelley, Douglas

2017-11-01

Recent discoveries have uncovered a cerebrospinal fluid (CSF) transport system in the perivascular spaces (PVS) of the mammalian brain which clears excess extracellular fluid and protein waste products. The oscillatory pattern of CSF flow has long been attributed to arterial pulsations due to cardiac contractility but limitations in imaging techniques have impeded quantitative measurement of flow rates within the PVS. In this talk, we describe quantitative measurements from the first ever direct imaging of CSF flow in the PVS of a mouse brain. We perform particle tracking velocimetry to obtain time-resolved velocity measurements. To identify the cardiac and/or respiratory dependence of the flow, while imaging, we simultaneously record the mouse's electrocardiogram and respiration. Our measurements conclusively indicate that CSF pulsatility in the arterial PVS is directly driven by the cardiac cycle and not by the respiratory cycle or cerebral vasomotion. These results offer a substantial step forward in understanding bulk flow of CSF in the mammalian brain and may have important implications related to neurodegenerative diseases.

Design and evaluation of a flow-to-frequency converter circuit with thermal feedback

NASA Astrophysics Data System (ADS)

Pawlowski, Eligiusz

2017-05-01

A novel thermal flow sensor with a frequency output is presented. The sensor provides a pulse-train output whose frequency is related to the fluid flow rate around a self-heating thermistor. The integrating properties of the temperature sensor have been used, which allowed for realization of the pulse frequency modulator with a thermal feedback loop, stabilizing the temperature of the sensor placed in the flowing medium. The system assures a balance of the amount of heat supplied in the impulses to the sensor and the heat given up by the sensor in a continuous way to the flowing medium. Therefore the frequency of output pulse-train is proportional to the medium flow velocity around the sensor. The special feature of the presented solution is the total integration of the thermal sensor with the measurement signal conditioning system. i.e. the sensor and conditioning system are not separate elements of the measurement circuit, but constitute a whole in the form of a thermal heat-balance mode flow-to-frequency converter. The frequency signal from the converter may be directly connected to the microprocessor digital input, which with use of the standard built-in counters may convert the frequency into a numerical value of high precision. The sensor has been experimentally characterized as a function of the average flow velocity of air at room temperature.

Computer aided approximation of flow rate through systemic-pulmonary arterial shunts (SPAS).

PubMed

Vennemann, Peter; Montag, Michael; Peters, Franz; Merzkirch, Wolfgang

2012-02-22

The discrimination of flow rates through bronchial arteries that are affected by pathological SPAS today still happens solely qualitatively. A reproducible quantification of flow rates, however, would enable the comprehension of phenomena like the intensified shunt perfusion seen in cases of chronic inflammations or the characterization of SPAS that may cause cardiovascular problems. A computational program is developed, that allows the modeling of individual bronchial arteries on the basis of the information provided by angiography. Angiographic images are available from the standard clinical assessment of SPAS. The flow through continuous and geometrically measurable vessel segments and SPAS is given by the law of Hagen-Poiseuille. The discharge through healthy branches is calculated by means of allometric scaling laws. The simulation results are verified by flow experiments in artificial vessel networks made of glass and PE tubing. The experimental set-up mimics realistic, pulsating pressure and flow conditions. When applied to the artificial vessel networks, the model described herein provides results for the volumetric flow rate that differ from values measured in laboratory experiments by <6%. The computer model is also applied to real angiographic images. Due to inaccuracies during the deduction of the geometry and due to necessary simplifications of the model, we expect significant deviations between calculated and real flow rates in bronchial systems. Nevertheless, the presented method enables the physician to objectively estimate the order of magnitude of volumetric flow through individual SPAS fairly independently from his experience and without the need of measurements additional to the mandatory angiography.

Application of digital interferogram evaluation techniques to the measurement of 3-D flow fields

NASA Technical Reports Server (NTRS)

Becker, Friedhelm; Yu, Yung H.

1987-01-01

A system for digitally evaluating interferograms, based on an image processing system connected to a host computer, was implemented. The system supports one- and two-dimensional interferogram evaluations. Interferograms are digitized, enhanced, and then segmented. The fringe coordinates are extracted, and the fringes are represented as polygonal data structures. Fringe numbering and fringe interpolation modules are implemented. The system supports editing and interactive features, as well as graphic visualization. An application of the system to the evaluation of double exposure interferograms from the transonic flow field around a helicopter blade and the reconstruction of the three dimensional flow field is given.

An affordable and accurate conductivity probe for density measurements in stratified flows

NASA Astrophysics Data System (ADS)

Carminati, Marco; Luzzatto-Fegiz, Paolo

2015-11-01

In stratified flow experiments, conductivity (combined with temperature) is often used to measure density. The probes typically used can provide very fine spatial scales, but can be fragile, expensive to replace, and sensitive to environmental noise. A complementary instrument, comprising a low-cost conductivity probe, would prove valuable in a wide range of applications where resolving extremely small spatial scales is not needed. We propose using micro-USB cables as the actual conductivity sensors. By removing the metallic shield from a micro-B connector, 5 gold-plated microelectrodes are exposed and available for 4-wire measurements. These have a cell constant ~550m-1, an intrinsic thermal noise of at most 30pA/Hz1/2, as well as sub-millisecond time response, making them highly suitable for many stratified flow measurements. In addition, we present the design of a custom electronic board (Arduino-based and Matlab-controlled) for simultaneous acquisition from 4 sensors, with resolution (in conductivity, and resulting density) exceeding the performance of typical existing probes. We illustrate the use of our conductivity-measuring system through stratified flow experiments, and describe plans to release simple instructions to construct our complete system for around 200.

Measurement of Separated Flow Structures Using a Multiple-Camera DPIV System. [conducted in the Langley Subsonic Basic Research Tunnel

NASA Technical Reports Server (NTRS)

Humphreys, William M., Jr.; Bartram, Scott M.

2001-01-01

A novel multiple-camera system for the recording of digital particle image velocimetry (DPIV) images acquired in a two-dimensional separating/reattaching flow is described. The measurements were performed in the NASA Langley Subsonic Basic Research Tunnel as part of an overall series of experiments involving the simultaneous acquisition of dynamic surface pressures and off-body velocities. The DPIV system utilized two frequency-doubled Nd:YAG lasers to generate two coplanar, orthogonally polarized light sheets directed upstream along the horizontal centerline of the test model. A recording system containing two pairs of matched high resolution, 8-bit cameras was used to separate and capture images of illuminated tracer particles embedded in the flow field. Background image subtraction was used to reduce undesirable flare light emanating from the surface of the model, and custom pixel alignment algorithms were employed to provide accurate registration among the various cameras. Spatial cross correlation analysis with median filter validation was used to determine the instantaneous velocity structure in the separating/reattaching flow region illuminated by the laser light sheets. In operation the DPIV system exhibited a good ability to resolve large-scale separated flow structures with acceptable accuracy over the extended field of view of the cameras. The recording system design provided enhanced performance versus traditional DPIV systems by allowing a variety of standard and non-standard cameras to be easily incorporated into the system.

Critical and supercritical flows in two unstable, mountain rivers, Toutle river system, Washington

USGS Publications Warehouse

Simon, Andrew; Hardison, J. H.

1994-01-01

Critical and supercritical flows are generally considered to be rare occurrences in natural river channels. This paper presents data and results pertaining to the existence of measured critical and supercritical flows at gaging stations on the North Fork Toutle River (NFT) and Toutle River main stem (TR). The data set includes 930 discharge measurements made by the staff of the U.S. Geological Survey, Cascades Volcano Observatory, between 1980 and 1989.

Miniature drag-force anemometer

NASA Technical Reports Server (NTRS)

Krause, L. N.; Fralick, G. C.

1977-01-01

A miniature drag-force anemometer is described which is capable of measuring dynamic velocity head and flow direction. The anemometer consists of a silicon cantilever beam 2.5 mm long, 1.5 mm wide, and 0.25 mm thick with an integrated diffused strain-gage bridge, located at the base of the beam, as the force measuring element. The dynamics of the beam are like those of a second-order system with a natural frequency of about 42 kHz and a damping coefficient of 0.007. The anemometer can be used in both forward and reversed flow. Measured flow characteristics up to Mach 0.6 are presented along with application examples including turbulence measurements.

Study of Plasma Flows Generated in Plasma Focus Discharge in Different Regimes of Working Gas Filling

NASA Astrophysics Data System (ADS)

Voitenko, D. A.; Ananyev, S. S.; Astapenko, G. I.; Basilaia, A. D.; Markolia, A. I.; Mitrofanov, K. N.; Myalton, V. V.; Timoshenko, A. P.; Kharrasov, A. M.; Krauz, V. I.

2017-12-01

Results are presented from experimental studies of the plasma flows generated in the KPF-4 Phoenix Mather-type plasma focus device (Sukhum Physical Technical Institute). In order to study how the formation and dynamics of the plasma flow depend on the initial distribution of the working gas, a system of pulsed gas puffing into the discharge volume was developed. The system allows one to create profiled gas distributions, including those with a reduced gas density in the region of plasma flow propagation. Results of measurements of the magnetic field, flow profile, and flow deceleration dynamics at different initial distributions of the gas pressure are presented.

Tidally driven pore water exchange within offshore intertidal sandbanks: Part II numerical simulations

NASA Astrophysics Data System (ADS)

Gibbes, B.; Robinson, C.; Li, L.; Lockington, D.; Li, H.

2008-12-01

Field measurements presented by [Gibbes, B., Robinson, C., Li, L., Lockington, D.A., Carey, H., 2008. Tidally driven pore water exchange within offshore intertidal sandbanks: Part I Field measurements. Estuarine, Coastal and Shelf Science 79, pp. 121-132.] revealed a tidally driven pore water flow system within an offshore intertidal sandbank in Moreton Bay, Australia. The field data suggested that this flow system might be capable of delivering nutrients, and in particular bio-available iron, across the sediment-water interface. Bio-available iron has been implicated as a key nutrient in the growth of the toxic marine cyanobacteria Lyngbya majuscula and therefore this pore water exchange process is of interest at sites where L. majuscula blooms have been observed. In this study two-dimensional numerical simulations were used in conjunction with hydraulic data from field measurements to further investigate the tidally induced pore water flow patterns. Simulation results generally showed good agreement with the field data and revealed a more complex residual pore water flow system in the sandbank than shown by the field data. The flow system, strongly influenced by the geometry of the sandbank, was characterized by two circulation cells which resulted in pore water discharge at the bank edge and also to a permanently ponded area within the sandbank interior. Simulated discharge volumes in these two zones were in the order of 0.813 m 3 and 0.143 m 3 per meter width (along shore) of sandbank per tidal cycle at the bank edge and sandbank interior respectively. Transit times of pore water circulating through these cells were found to range from ≈ 17 days to > 60 years with an average time of 780 days. The results suggest that the tidally driven flow systems might provide a mechanism for transport of bio-available iron across the sediment-water interface. This flow could constitute a previously unrecognized source of bio-available iron for L. majuscula blooms in the Bay.

Experiment data for determination of uncertainty of two-phase mass flow rate in a Semiscale Mod-3 system spool piece at Karlsruhe Kernforschungzentrum. [PWR

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

Stephens, A.G.

1979-06-01

Steady state, steam-water testing of a Semiscale Mod-3 system instrumented spool piece was accomplished in the Gesellschaft fur Kernforschung (GfK) facility at Karlsruhe Kernforschungzentrum, West Germany. The testing was undertaken to determine the accuracy of spool piece, two-phase mass flow rate, inferential measurements by comparison with upstream single-phase reference measurements. Other two-phase measurements were also made to aid in understanding the flow conditions and to implement data reduction. A total of 132 single- and two-phase test points were acquired, covering pressures from 0.4 to 7.5 MPa, flow rates from 0.5 to 4.9 kg/s, and two-phase mixture qualities from 1.0 tomore » 83% in the 66.7 mm inside diameter spool piece. The report includes a detailed description of the hardware and software and a tabulation of the data.« less

Simulating Nailfold Capillaroscopy Sequences to Evaluate Algorithms for Blood Flow Estimation

PubMed Central

Tresadern, P. A.; Berks, M.; Murray, A. K.; Dinsdale, G.; Taylor, C. J.; Herrick, A. L.

2016-01-01

The effects of systemic sclerosis (SSc) – a disease of the connective tissue causing blood flow problems that can require amputation of the fingers – can be observed indirectly by imaging the capillaries at the nailfold, though taking quantitative measures such as blood flow to diagnose the disease and monitor its progression is not easy. Optical flow algorithms may be applied, though without ground truth (i.e. known blood flow) it is hard to evaluate their accuracy. We propose an image model that generates realistic capillaroscopy videos with known flow, and use this model to quantify the effect of flow rate, cell density and contrast (among others) on estimated flow. This resource will help researchers to design systems that are robust under real-world conditions. PMID:24110268

Application of video-cameras for quality control and sampling optimisation of hydrological and erosion measurements in a catchment

NASA Astrophysics Data System (ADS)

Lora-Millán, Julio S.; Taguas, Encarnacion V.; Gomez, Jose A.; Perez, Rafael

2014-05-01

Long term soil erosion studies imply substantial efforts, particularly when there is the need to maintain continuous measurements. There are high costs associated to maintenance of field equipment keeping and quality control of data collection. Energy supply and/or electronic failures, vandalism and burglary are common causes of gaps in datasets, reducing their reach in many cases. In this work, a system of three video-cameras, a recorder and a transmission modem (3G technology) has been set up in a gauging station where rainfall, runoff flow and sediment concentration are monitored. The gauging station is located in the outlet of an olive orchard catchment of 6.4 ha. Rainfall is measured with one automatic raingauge that records intensity at one minute intervals. The discharge is measured by a flume of critical flow depth, where the water is recorded by an ultrasonic sensor. When the water level rises to a predetermined level, the automatic sampler turns on and fills a bottle at different intervals according to a program depending on the antecedent precipitation. A data logger controls the instruments' functions and records the data. The purpose of the video-camera system is to improve the quality of the dataset by i) the visual analysis of the measurement conditions of flow into the flume; ii) the optimisation of the sampling programs. The cameras are positioned to record the flow at the approximation and the gorge of the flume. In order to contrast the values of ultrasonic sensor, there is a third camera recording the flow level close to a measure tape. This system is activated when the ultrasonic sensor detects a height threshold, equivalent to an electric intensity level. Thus, only when there is enough flow, video-cameras record the event. This simplifies post-processing and reduces the cost of download of recordings. The preliminary contrast analysis will be presented as well as the main improvements in the sample program.

Turbulence measurements in hypersonic boundary layers using constant-temperature anemometry and Reynolds stress measurements in hypersonic boundary layers

NASA Technical Reports Server (NTRS)

Spina, Eric F.

1995-01-01

The primary objective in the two research investigations performed under NASA Langley sponsorship (Turbulence measurements in hypersonic boundary layers using constant temperature anemometry and Reynolds stress measurements in hypersonic boundary layers) has been to increase the understanding of the physics of hypersonic turbulent boundary layers. The study began with an extension of constant-temperature thermal anemometry techniques to a Mach 11 helium flow, including careful examinations of hot-wire construction techniques, system response, and system calibration. This was followed by the application of these techniques to the exploration of a Mach 11 helium turbulent boundary layer (To approximately 290 K). The data that was acquired over the course of more than two years consists of instantaneous streamwise mass flux measurements at a frequency response of about 500 kHz. The data are of exceptional quality in both the time and frequency domain and possess a high degree of repeatability. The data analysis that has been performed to date has added significantly to the body of knowledge on hypersonic turbulence, and the data reduction is continuing. An attempt was then made to extend these thermal anemometry techniques to higher enthalpy flows, starting with a Mach 6 air flow with a stagnation temperature just above that needed to prevent liquefaction (To approximately 475 F). Conventional hot-wire anemometry proved to be inadequate for the selected high-temperature, high dynamic pressure flow, with frequent wire breakage and poor system frequency response. The use of hot-film anemometry has since been investigated for these higher-enthalpy, severe environment flows. The difficulty with using hot-film probes for dynamic (turbulence) measurements is associated with construction limitations and conduction of heat into the film substrate. Work continues under a NASA GSRP grant on the development of a hot film probe that overcomes these shortcomings for hypersonic flows. Each of the research tasks performed during the NASA Langley research grants is discussed separately below.

Measurements of energy distribution and thrust for microwave plasma coupling of electrical energy to hydrogen for propulsion

NASA Technical Reports Server (NTRS)

Morin, T.; Chapman, R.; Filpus, J.; Hawley, M.; Kerber, R.; Asmussen, J.; Nakanishi, S.

1982-01-01

A microwave plasma system for transfer of electrical energy to hydrogen flowing through the system has potential application for coupling energy to a flowing gas in the electrothermal propulsion concept. Experimental systems have been designed and built for determination of the energy inputs and outputs and thrust for the microwave coupling of energy to hydrogen. Results for experiments with pressure in the range 100 microns-6 torr, hydrogen flow rate up to 1000 micronmoles/s, and total absorbed power to 700 w are presented.

Thermal and heat flow instrumentation for the space shuttle Thermal Protection System

NASA Technical Reports Server (NTRS)

Hartman, G. J.; Neuner, G. J.; Pavlosky, J.

1974-01-01

The 100 mission lifetime requirement for the space shuttle orbiter vehicle dictates a unique set of requirements for the Thermal Protection System (TPS) thermal and heat flow instrumentation. This paper describes the design and development of such instrumentation with emphasis on assessment of the accuracy of the measurements when the instrumentation is an integral part of the TPS. The temperature and heat flow sensors considered for this application are described and the optimum choices discussed. Installation techniques are explored and the resulting impact on the system error defined.

3D real-time visualization of blood flow in cerebral aneurysms by light field particle image velocimetry

NASA Astrophysics Data System (ADS)

Carlsohn, Matthias F.; Kemmling, André; Petersen, Arne; Wietzke, Lennart

2016-04-01

Cerebral aneurysms require endovascular treatment to eliminate potentially lethal hemorrhagic rupture by hemostasis of blood flow within the aneurysm. Devices (e.g. coils and flow diverters) promote homeostasis, however, measurement of blood flow within an aneurysm or cerebral vessel before and after device placement on a microscopic level has not been possible so far. This would allow better individualized treatment planning and improve manufacture design of devices. For experimental analysis, direct measurement of real-time microscopic cerebrovascular flow in micro-structures may be an alternative to computed flow simulations. An application of microscopic aneurysm flow measurement on a regular basis to empirically assess a high number of different anatomic shapes and the corresponding effect of different devices would require a fast and reliable method at low cost with high throughout assessment. Transparent three dimensional 3D models of brain vessels and aneurysms may be used for microscopic flow measurements by particle image velocimetry (PIV), however, up to now the size of structures has set the limits for conventional 3D-imaging camera set-ups. On line flow assessment requires additional computational power to cope with the processing large amounts of data generated by sequences of multi-view stereo images, e.g. generated by a light field camera capturing the 3D information by plenoptic imaging of complex flow processes. Recently, a fast and low cost workflow for producing patient specific three dimensional models of cerebral arteries has been established by stereo-lithographic (SLA) 3D printing. These 3D arterial models are transparent an exhibit a replication precision within a submillimeter range required for accurate flow measurements under physiological conditions. We therefore test the feasibility of microscopic flow measurements by PIV analysis using a plenoptic camera system capturing light field image sequences. Averaging across a sequence of single double or triple shots of flashed images enables reconstruction of the real-time corpuscular flow through the vessel system before and after device placement. This approach could enable 3D-insight of microscopic flow within blood vessels and aneurysms at submillimeter resolution. We present an approach that allows real-time assessment of 3D particle flow by high-speed light field image analysis including a solution that addresses high computational load by image processing. The imaging set-up accomplishes fast and reliable PIV analysis in transparent 3D models of brain aneurysms at low cost. High throughput microscopic flow assessment of different shapes of brain aneurysms may therefore be possibly required for patient specific device designs.

An investigation of the basic physics of irrigation in urology and the role of automated pump irrigation in cystoscopy.

PubMed

Chang, Dwayne; Manecksha, Rustom P; Syrrakos, Konstantinos; Lawrentschuk, Nathan

2012-01-01

To investigate the effects of height, external pressure, and bladder fullness on the flow rate in continuous, non-continuous cystoscopy and the automated irrigation fluid pumping system (AIFPS). Each experiment had two 2-litre 0.9% saline bags connected to a continuous, non-continuous cystoscope or AIFPS via irrigation tubing. Other equipment included height-adjustable drip poles, uroflowmetry devices, and model bladders. In Experiment 1, saline bags were elevated to measure the increment in flow rate. In Experiment 2, saline bags were placed under external pressures to evaluate the effect on flow rate. In Experiment 3, flow rate changes in response to variable bladder fullness were measured. Elevating saline bags caused an increase in flow rates, however the increment slowed down beyond a height of 80 cm. Increase in external pressure on saline bags elevated flow rates, but inconsistently. A fuller bladder led to a decrease in flow rates. In all experiments, the AIFPS posted consistent flow rates. Traditional irrigation systems were susceptible to changes in height of irrigation solution, external pressure application, and bladder fullness thus creating inconsistent flow rates. The AIFPS produced consistent flow rates and was not affected by any of the factors investigated in the study.

A Bayesian changepoint-threshold model to examine the effect of TMDL implementation on the flow-nitrogen concentration relationship in the Neuse River basin.

PubMed

Alameddine, Ibrahim; Qian, Song S; Reckhow, Kenneth H

2011-01-01

In-stream nutrient concentrations are well known to exhibit a strong relationship with river flow. The use of flow measurements to predict nutrient concentrations and subsequently nutrient loads is common in water quality modeling. Nevertheless, most adopted models assume that the relationship between flow and concentration is fixed across time as well as across different flow regimes. In this study, we developed a Bayesian changepoint-threshold model that relaxes these constraints and allows for the identification and quantification of any changes in the underlying flow-concentration relationship across time. The results from our study support the occurrence of a changepoint in time around the year 1999, which coincided with the period of implementing nitrogen control measures as part of the TMDL program developed for the Neuse Estuary in North Carolina. The occurrence of the changepoint challenges the underlying assumption of temporal invariance in the flow-concentrations relationship. The model results also point towards a transition in the river nitrogen delivery system from a point source dominated loading system towards a more complicated nonlinear system, where non-point source nutrient delivery plays a major role. Moreover, we use the developed model to assess the effectiveness of the nitrogen reduction measures in achieving a 30% drop in loading. The results indicate that while there is a strong evidence of a load reduction, there still remains a high level of uncertainty associated with the mean nitrogen load reduction. We show that the level of uncertainty around the estimated load reduction is not random but is flow related. Copyright © 2010 Elsevier Ltd. All rights reserved.

Application of ``POLIS'' PIV system for measurement of velocity fields in a supersonic flow of the wind tunnels

NASA Astrophysics Data System (ADS)

Akhmetbekov, Y. K.; Bilsky, A. V.; Markovich, D. M.; Maslov, A. A.; Polivanov, P. A.; Tsyryul'Nikov, I. S.; Yaroslavtsev, M. I.

2009-09-01

Measurement results on the mean velocity fields and fields of velocity pulsations in the supersonic flows obtained by means of the PIV measurement set “POLIS” are presented. Experiments were carried out in the supersonic blow-down and stationary wind tunnels at the Mach numbers of 4.85 and 6. The method of flow velocity estimate in the test section of the blow-down wind tunnel was grounded by direct measurements of stagnation pressure in the setup settling chamber. The size of tracer particles introduced into the supersonic flow by a mist generator was determined; data on the structure of pulsating velocity in a track of an oblique-cut gas-dynamic whistle were obtained under the conditions of self-oscillations.

Application of laser Doppler velocimeter to chemical vapor laser system

NASA Technical Reports Server (NTRS)

Gartrell, Luther R.; Hunter, William W., Jr.; Lee, Ja H.; Fletcher, Mark T.; Tabibi, Bagher M.

1993-01-01

A laser Doppler velocimeter (LDV) system was used to measure iodide vapor flow fields inside two different-sized tubes. Typical velocity profiles across the laser tubes were obtained with an estimated +/-1 percent bias and +/-0.3 to 0.5 percent random uncertainty in the mean values and +/-2.5 percent random uncertainty in the turbulence-intensity values. Centerline velocities and turbulence intensities for various longitudinal locations ranged from 13 to 17.5 m/sec and 6 to 20 percent, respectively. In view of these findings, the effects of turbulence should be considered for flow field modeling. The LDV system provided calibration data for pressure and mass flow systems used routinely to monitor the research laser gas flow velocity.

The effect of vacuum devices on penile hemodynamics

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

Katz, P.G.; Haden, H.T.; Mulligan, T.

1990-01-01

External vacuum devices are being used increasingly for the management of erectile dysfunction. There is limited information regarding the effect of vacuum devices on penile blood flow and potential for ischemic penile injury. The penile xenon washout rate was measured before and after application of 2 vacuum systems in 15 subjects. Compared to flaccid state measurements the xenon washout rate did not change significantly with the Synergist Erection System but it was significantly reduced with the Osbon ErecAid System. However, the degree and duration of decrease in penile blood flow that may result in ischemic changes are unknown.

A Hydrostatic Bearing Test System for Measuring Bearing Load Using Magnetic-Fluid Lubricants.

PubMed

Weng, Huei Chu; Chen, Lu-Yu

2016-05-01

This paper conducts a study on the design of a hydrostatic bearing test system. It involves the determination of viscous properties of magnetic-fluid lubricants. The load of a hydrostatic thrust bearing using a water-based magnetite nanofluid of varying volume flow rate is measured under an applied external induction field via the test system. Results reveal that the presence of nanoparticles in a carrier liquid would cause an enhanced bearing load. Such an effect could be further magnified by increasing the lubricant volume flow rate or the external induction field strength.

Contactless Inductive Bubble Detection in a Liquid Metal Flow

PubMed Central

Gundrum, Thomas; Büttner, Philipp; Dekdouk, Bachir; Peyton, Anthony; Wondrak, Thomas; Galindo, Vladimir; Eckert, Sven

2016-01-01

The detection of bubbles in liquid metals is important for many technical applications. The opaqueness and the high temperature of liquid metals set high demands on the measurement system. The high electrical conductivity of the liquid metal can be exploited for contactless methods based on electromagnetic induction. We will present a measurement system which consists of one excitation coil and a pickup coil system on the opposite sides of the pipe. With this sensor we were able to detect bubbles in a sodium flow inside a stainless steel pipe and bubbles in a column filled with a liquid Gallium alloy. PMID:26751444

Optimal plane search method in blood flow measurements by magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Bargiel, Pawel; Orkisz, Maciej; Przelaskowski, Artur; Piatkowska-Janko, Ewa; Bogorodzki, Piotr; Wolak, Tomasz

2004-07-01

This paper offers an algorithm for determining the blood flow parameters in the neck vessel segments using a single (optimal) measurement plane instead of the usual approach involving four planes orthogonal to the artery axis. This new approach aims at significantly shortening the time required to complete measurements using Nuclear Magnetic Resonance techniques. Based on a defined error function, the algorithm scans the solution space to find the minimum of the error function, and thus to determine a single plane characterized by a minimum measurement error, which allows for an accurate measurement of blood flow in the four carotid arteries. The paper also comprises a practical implementation of this method (as a module of a larger imaging-measuring system), including preliminary research results.

Debris flow hazards mitigation--Mechanics, prediction, and assessment

USGS Publications Warehouse

Chen, C.-L.; Major, J.J.

2007-01-01

These proceedings contain papers presented at the Fourth International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment held in Chengdu, China, September 10-13, 2007. The papers cover a wide range of topics on debris-flow science and engineering, including the factors triggering debris flows, geomorphic effects, mechanics of debris flows (e.g., rheology, fluvial mechanisms, erosion and deposition processes), numerical modeling, various debris-flow experiments, landslide-induced debris flows, assessment of debris-flow hazards and risk, field observations and measurements, monitoring and alert systems, structural and non-structural countermeasures against debris-flow hazards and case studies. The papers reflect the latest devel-opments and advances in debris-flow research. Several studies discuss the development and appli-cation of Geographic Information System (GIS) and Remote Sensing (RS) technologies in debris-flow hazard/risk assessment. Timely topics presented in a few papers also include the development of new or innovative techniques for debris-flow monitoring and alert systems, especially an infra-sound acoustic sensor for detecting debris flows. Many case studies illustrate a wide variety of debris-flow hazards and related phenomena as well as their hazardous effects on human activities and settlements.

Blood flow velocity measurement by endovascular Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Sun, Cuiru; Nolte, Felix; Vuong, Barry; Cheng, Kyle H. Y.; Lee, Kenneth K. C.; Standish, Beau A.; Courtney, Brian; Marotta, Tom R.; Yang, Victor X. D.

2013-03-01

Blood flow velocity and volumetric flow measurements are important parameters for assessment of the severity of stenosis and the outcome of interventional therapy. However, feasibility of intravascular flow measurement using a rotational catheter based phase resolved Doppler optical coherence tomography (DOCT) is difficult. Motion artefacts induced by the rotating optical imaging catheter, and the radially dependent noise background of measured Doppler signals are the main challenges encountered. In this study, a custom-made data acquisition system and developed algorithms to remove non-uniform rotational distortion (NURD) induced phase shift artefact by tracking the phase shift observed on catheter sheath. The flow velocity is calculated from Doppler shift obtained by Kasai autocorrelation after motion artefact removal. Blood flow velocity profiles in porcine carotid arteries in vivo were obtained at 100 frames/s with 500 A-lines/frame and DOCT images were taken at 20 frames/s with 2500 A-lines/frame. Time-varying velocity profiles were obtained at an artery branch. Furthermore, the identification of a vein adjacent to the catheterized vessel based on the color Doppler signal was also observed. The absolute measurement of intravascular flow using a rotating fiber catheter can provide insights to different stages of interventional treatment of stenosis in carotid artery.

Measurement of Fracture Aperture Fields Using Ttransmitted Light: An Evaluation of Measurement Errors and their Influence on Simulations of Flow and Transport through a Single Fracture

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

Detwiler, Russell L.; Glass, Robert J.; Pringle, Scott E.

Understanding of single and multi-phase flow and transport in fractures can be greatly enhanced through experimentation in transparent systems (analogs or replicas) where light transmission techniques yield quantitative measurements of aperture, solute concentration, and phase saturation fields. Here we quanti@ aperture field measurement error and demonstrate the influence of this error on the results of flow and transport simulations (hypothesized experimental results) through saturated and partially saturated fractures. find that precision and accuracy can be balanced to greatly improve the technique and We present a measurement protocol to obtain a minimum error field. Simulation results show an increased sensitivity tomore » error as we move from flow to transport and from saturated to partially saturated conditions. Significant sensitivity under partially saturated conditions results in differences in channeling and multiple-peaked breakthrough curves. These results emphasize the critical importance of defining and minimizing error for studies of flow and transpoti in single fractures.« less

Continuous-flow free acid monitoring method and system

DOEpatents

Strain, J.E.; Ross, H.H.

1980-01-11

A free acid monitoring method and apparatus is provided for continuously measuring the excess acid present in a process stream. The disclosed monitoring system and method is based on the relationship of the partial pressure ratio of water and acid in equilibrium with an acid solution at constant temperature. A portion of the process stream is pumped into and flows through the monitor under the influence of gravity and back to the process stream. A continuous flowing sample is vaporized at a constant temperature and the vapor is subsequently condensed. Conductivity measurements of the condensate produces a nonlinear response function from which the free acid molarity of the sample process stream is determined.

Continuous-flow free acid monitoring method and system

DOEpatents

Strain, James E.; Ross, Harley H.

1981-01-01

A free acid monitoring method and apparatus is provided for continuously measuring the excess acid present in a process stream. The disclosed monitoring system and method is based on the relationship of the partial pressure ratio of water and acid in equilibrium with an acid solution at constant temperature. A portion of the process stream is pumped into and flows through the monitor under the influence of gravity and back to the process stream. A continuous flowing sample is vaporized at a constant temperature and the vapor is subsequently condensed. Conductivity measurements of the condensate produces a nonlinear response function from which the free acid molarity of the sample process stream is determined.

A Comparison of Electromagnetic Induction Mapping to Measurements of Maximum Effluent Flow Depth for Assessing Flow Paths in Vegetative Treatment Areas

USDA-ARS?s Scientific Manuscript database

Vegetative treatment systems (VTSs) are one type of control structure that has shown potential to control runoff from open feedlots. To achieve maximum performance, sheet-flow over the width of the vegetative treatment area (VTA) is required. Tools, such as maps of flow paths through the VTA, are ne...

The application of a unique flow modeling technique to complex combustion systems

NASA Astrophysics Data System (ADS)

Waslo, J.; Hasegawa, T.; Hilt, M. B.

1986-06-01

This paper describes the application of a unique three-dimensional water flow modeling technique to the study of complex fluid flow patterns within an advanced gas turbine combustor. The visualization technique uses light scattering, coupled with real-time image processing, to determine flow fields. Additional image processing is used to make concentration measurements within the combustor.

Circadian changes in uterine artery and ovarian stromal blood flow after pituitary down-regulation.

PubMed

Chan, Carina C W; Ng, Ernest H Y; Tang, Oi-Shan; Ho, Pak-Chung

2005-09-01

To investigate changes in the uterine artery and ovarian stromal blood flow in relation to the time of the day after pituitary down-regulation during in vitro fertilization treatment. Thirteen women were recruited. The uterine artery blood flow was studied using pulsed color Doppler ultrasonography and the ovarian stromal blood flow was measured using three-dimensional power Doppler ultrasonography. Ultrasound scan examinations and blood pressure measurements were performed in the morning and evening. The diastolic and the mean arterial pressures were significantly higher in the evening. An increase in the uterine artery pulsatility index and resistance index in the evening was observed. The ovarian vascularization index, vascularization flow index, and right ovarian flow index were significantly lower in the evening. Despite the small sample size, we have demonstrated the presence of a diurnal change in uterine artery and ovarian stromal blood flow after pituitary down-regulation. Such changes may be related to the systemic change in the sympathetic system and hence vascular resistance. Future study regarding ovarian stromal blood flow should take into account the effect of the time of the day on the readings in order to avoid misleading interpretation of data.

Modeling and measuring non-Newtonian shear flows of soft interfaces

NASA Astrophysics Data System (ADS)

Lopez, Juan; Raghunandan, Aditya; Underhill, Patrick; Hirsa, Amir

2017-11-01

Soft interfaces of polymers, particles, and proteins between fluid phases are ubiquitous in industrial and natural processes. The flow response of such systems to deformation is often not linear, as one would expect for Newtonian interfaces. The resistance to (pure shear) flow of interfaces is generally characterized by a single intrinsic material property, the surface shear viscosity. Predicted shear responses of Newtonian interfaces have achieved consensus across a wide range of flow conditions and measurement devices, when the nonlinear hydrodynamic coupling to the bulk phase is correctly accounted for. However, predicting the flows of sheared non-Newtonian interfaces remains a challenge. Here, we introduce a computational model that incorporates a non-Newtonian constitutive equation for the sheared interface and properly accounts for the coupled interfacial and bulk phase flows. We compare predictions to experiments performed with a model phospholipid system, DPPC - the main constituent of mammalian lung surfactant. Densely packed films of DPPC are directly sheared in a knife-edge surface viscometer. Yield-stress and shear thinning behaviors are shown to be accurately captured across hydrodynamic regimes straddling the Stokes flow limit to inertia dominated flows. Supported by NASA Grant NNX13AQ22G.

Steam distribution and energy delivery optimization using wireless sensors

NASA Astrophysics Data System (ADS)

Olama, Mohammed M.; Allgood, Glenn O.; Kuruganti, Teja P.; Sukumar, Sreenivas R.; Djouadi, Seddik M.; Lake, Joe E.

2011-05-01

The Extreme Measurement Communications Center at Oak Ridge National Laboratory (ORNL) explores the deployment of a wireless sensor system with a real-time measurement-based energy efficiency optimization framework in the ORNL campus. With particular focus on the 12-mile long steam distribution network in our campus, we propose an integrated system-level approach to optimize the energy delivery within the steam distribution system. We address the goal of achieving significant energy-saving in steam lines by monitoring and acting on leaking steam valves/traps. Our approach leverages an integrated wireless sensor and real-time monitoring capabilities. We make assessments on the real-time status of the distribution system by mounting acoustic sensors on the steam pipes/traps/valves and observe the state measurements of these sensors. Our assessments are based on analysis of the wireless sensor measurements. We describe Fourier-spectrum based algorithms that interpret acoustic vibration sensor data to characterize flows and classify the steam system status. We are able to present the sensor readings, steam flow, steam trap status and the assessed alerts as an interactive overlay within a web-based Google Earth geographic platform that enables decision makers to take remedial action. We believe our demonstration serves as an instantiation of a platform that extends implementation to include newer modalities to manage water flow, sewage and energy consumption.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device.

PubMed

Gohean, Jeffrey R; George, Mitchell J; Pate, Thomas D; Kurusz, Mark; Longoria, Raul G; Smalling, Richard W

2013-01-01

The purpose of this investigation is to use a computational model to compare a synchronized valveless pulsatile left ventricular assist device with continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate the support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous pulsatile valveless dual-piston positive displacement pump. These results were compared with measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared with the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device

PubMed Central

Gohean, Jeffrey R.; George, Mitchell J.; Pate, Thomas D.; Kurusz, Mark; Longoria, Raul G.; Smalling, Richard W.

2012-01-01

The purpose of this investigation is to utilize a computational model to compare a synchronized valveless pulsatile left ventricular assist device to continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous, pulsatile, valveless, dual piston positive displacement pump. These results were compared to measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared to the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device. PMID:23438771

Experimental and analytical study of close-coupled ventral nozzles for ASTOVL aircraft

NASA Technical Reports Server (NTRS)

Mcardle, Jack G.; Smith, C. Frederic

1990-01-01

Flow in a generic ventral nozzle system was studied experimentally and analytically with a block version of the PARC3D computational fluid dynamics program (a full Navier-Stokes equation solver) in order to evaluate the program's ability to predict system performance and internal flow patterns. For the experimental work a one-third-size model tailpipe with a single large rectangular ventral nozzle mounted normal to the tailpipe axis was tested with unheated air at steady-state pressure ratios up to 4.0. The end of the tailpipe was closed to simulate a blocked exhaust nozzle. Measurements showed about 5 1/2 percent flow-turning loss, reasonable nozzle performance coefficients, and a significant aftward axial component of thrust due to flow turning loss, reasonable nozzle performance coefficients, and a significant aftward axial component of thrust due to flow turning more than 90 deg. Flow behavior into and through the ventral duct is discussed and illustrated with paint streak flow visualization photographs. For the analytical work the same ventral system configuration was modeled with two computational grids to evaluate the effect of grid density. Both grids gave good results. The finer-grid solution produced more detailed flow patterns and predicted performance parameters, such as thrust and discharge coefficient, within 1 percent of the measured values. PARC3D flow visualization images are shown for comparison with the paint streak photographs. Modeling and computational issues encountered in the analytical work are discussed.

Measurement of crossflow vortices, attachment-line flow, and transition using microthin hot films

NASA Technical Reports Server (NTRS)

Mangalam, S. M.; Agarwal, N. K.; Maddalon, D. V.; Saric, W. S.

1990-01-01

A flow diagnostic experiment was conducted on a 45-deg swept-wing model using surface-mounted, multielement, microthin, hot-film sensors. The cross-flow vortex spacing, the attachment-line flow characteristics, and the transition region were all determined using an advanced data acquisition and instrumentation system. In addition to the frequencies of traveling waves predicted by linear stability theory, amplified disturbances at much higher frequencies were observed. Simultaneous measurements from sensors located at a number of chord and span locations highlighted the strong three-dimensionality of the boundary-layer flow in the presence of cross-flow vortices. The state of the attachment-line boundary layer was determined using a multielement sensor wrapped around the wing leading edge. The transition region flow characteristics were also identified.

Development of a high-resolution automatic digital (urine/electrolytes) flow volume and rate measurement system of miniature size

NASA Technical Reports Server (NTRS)

Liu, F. F.

1975-01-01

To aid in the quantitative analysis of man's physiological rhythms, a flowmeter to measure circadian patterns of electrolyte excretion during various environmental stresses was developed. One initial flowmeter was designed and fabricated, the sensor of which is the approximate size of a wristwatch. The detector section includes a special type of dielectric integrating type sensor which automatically controls, activates, and deactivates the flow sensor data output by determining the presence or absence of fluid flow in the system, including operation under zero-G conditions. The detector also provides qualitative data on the composition of the fluid. A compact electronic system was developed to indicate flow rate as well as total volume per release or the cumulative volume of several releases in digital/analog forms suitable for readout or telemetry. A suitable data readout instrument is also provided. Calibration and statistical analyses of the performance functions required of the flowmeter were also conducted.

Meter for very slow flows

NASA Technical Reports Server (NTRS)

Baxter, W. J., Jr.; Frant, M. S.; West, S. J.

1978-01-01

Solid-state sensing unit developed for use with NASA's Water-Quality Monitoring System can detect small velocity changes in slow moving fluid. Nonprotruding sensor is applicable to numerous other uses requiring sensitive measurement of slow flows.

Thermal margin protection system for a nuclear reactor

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

Musick, C.R.

1974-02-12

A thermal margin protection system for a nuclear reactor is described where the coolant flow flow trip point and the calculated thermal margin trip point are switched simultaneously and the thermal limit locus is made more restrictive as the allowable flow rate is decreased. The invention is characterized by calculation of the thermal limit Locus in response to applied signals which accurately represent reactor cold leg temperature and core power; cold leg temperature being corrected for stratification before being utilized and reactor power signals commensurate with power as a function of measured neutron flux and thermal energy added to themore » coolant being auctioneered to select the more conservative measure of power. The invention further comprises the compensation of the selected core power signal for the effects of core radial peaking factor under maximum coolant flow conditions. (Official Oazette)« less

Experimental Investigations on Microshock Waves and Contact Surfaces

NASA Astrophysics Data System (ADS)

Kai, Yun; Garen, Walter; Teubner, Ulrich

2018-02-01

The present work reports on progress in the research of a microshock wave. Because of the lack of a good understanding of the propagation mechanism of the microshock flow system (shock wave, contact surface, and boundary layer), the current work concentrates on measuring microshock flows with special attention paid to the contact surface. A novel setup involving a glass capillary (with a 200 or 300 μ m hydraulic diameter D ) and a high-speed magnetic valve is applied to generate a shock wave with a maximum initial Mach number of 1.3. The current work applies a laser differential interferometer to perform noncontact measurements of the microshock flow's trajectory, velocity, and density. The current work presents microscale measurements of the shock-contact distance L that solves the problem of calculating the scaling factor Sc =Re ×D /(4 L ) (introduced by Brouillette), which is a parameter characterizing the scaling effects of shock waves. The results show that in contrast to macroscopic shock waves, shock waves at the microscale have a different propagation or attenuation mechanism (key issue of this Letter) which cannot be described by the conventional "leaky piston" model. The main attenuation mechanism of microshock flow may be the ever slower moving contact surface, which drives the shock wave. Different from other measurements using pressure transducers, the current setup for density measurements resolves the whole microshock flow system.

Evaluation of exhaled nitric oxide in schoolchildren at different exhalation flow rates.

PubMed

Pedroletti, Christophe; Zetterquist, Wilhelm; Nordvall, Lennart; Alving, Kjell

2002-09-01

Nitric oxide (NO) in exhaled air is believed to reflect allergic inflammation in the airways. Measured levels of exhaled NO vary with the exhaled flow rate, which therefore must be standardized. The aim of this study was to estimate the optimal exhalation flow rate when measuring NO in exhaled air. We studied 15 asthmatic children (8-18 y) with elevated NO levels and 15 age-matched controls and focused on how the quality of the NO curve profile, the discriminatory power, and the reproducibility were influenced by the exhalation flow rate. We used an on-line system for NO measurements at six different exhalation flow rates in the interval of 11-382 mL/s. The fraction of exhaled nitric oxide (FENO) was highly flow-dependent as was expected. Intermediate flow rates yielded a flat and stable NO plateau and were considerably easier to interpret than those obtained at the highest and lowest flow rates. The ratio of FENO between asthmatics and controls was lower at higher flow rates and a considerable overlap in NO values was demonstrated at all flow rates except 50 mL/s. The reproducibility was much lower at more extreme flow rates and was best at 50 mL/s. We conclude that a target exhalation flow rate of approximately 50 mL/s is to be preferred using the single-breath method for on-line NO measurements in schoolchildren.

Field Measurements of Reynolds Stress near a Riverbank

USGS Publications Warehouse

Moody, J.A.; Smith, J.D.; ,

2002-01-01

The Reynolds stress field was measured near the bank of the Powder River in southeastern Montana. The measurements were made from the bank using an aluminum I-beam cantilevered over the water to support a carriage system for positioning an acoustic doppler velocimeter in a vertical plane perpendicular to 1) the bank and 2) the streamwise velocity field. During quasi-steady flow at the peak (71 m3s-1) of the spring snowmelt runoff in May 1996, turbulent velocities were measured at 25 Hertz along six vertical locations spaced 0.5 m apart and within about 3.5 m of the riverbank. When the turbulent velocities are transformed to the ray-isovel coordinate system appropriate for this two-dimension problem, the turbulent characteristics near the bed are consistent with similar field measurements made by others for the one-dimensional problem of uniform flow over a horizontal bed far from lateral boundaries. The three turbulent intensities, (u???2) 1/2, (v???2)1/2 and (w??? 2)1/2, normalized by the local shear velocity, u*, were essentially constant with distance above the bed along a ray and the average values were 2.1, 1.4, and 1.2. Future turbulence measurements could be improved by measuring the streamwise flow first, then determining the approximate location of the rays and isovels so that the turbulence measurements could be made along the approximated rays rather than along verticals. In addition, to improve the possibility making turbulence measurements during steady, uniform flow, the site should be carefully selected to minimize local flow accelerations caused by spatial variability of the riverbank. Also, the measurements should be made at times when the stage is constant, no local erosion or deposition of sediment occurs, and when wind velocities are small.

Laser Doppler detection systems for gas velocity measurement.

PubMed

Huffaker, R M

1970-05-01

The velocity of gas flow has been remotely measured using a technique which involves the coherent detection of scattered laser radiation from small particles suspended in the fluid utilizing the doppler effect. Suitable instrumentation for the study of wind tunnel type and atmospheric flows are described. Mainly for reasons of spatial resolution, a function of the laser wavelength, the wind tunnel system utilizes an argon laser operating at 0.5 micro. The relaxed spatial resolution requirement of atmospheric applications allows the use of a carbon dioxide laser, which has superior performance at a wavelength of 10.6 micro, a deduction made from signal-to-noise ratio considerations. Theoretical design considerations are given which consider Mie scattering predictions, two-phase flow effects, photomixing fundamentals, laser selection, spatial resolution, and spectral broadening effects. Preliminary experimental investigations using the instrumentation are detailed. The velocity profile of the flow field generated by a 1.27-cm diam subsonic jet was investigated, and the result compared favorably with a hot wire investigation conducted in the same jet. Measurements of wind velocity at a range of 50 m have also shown the considerable promise of the atmospheric system.

Assessment of Natural Ventilation System for a Typical Residential House in Poland

NASA Astrophysics Data System (ADS)

Antczak-Jarząbska, Romana; Krzaczek, Marek

2016-09-01

The paper presents the research results of field measurements campaign of natural ventilation performance and effectiveness in a residential building. The building is located in the microclimate whose parameters differ significantly in relation to a representative weather station. The measurement system recorded climate parameters and the physical variables characterizing the air flow in the rooms within 14 days of the winter season. The measurement results showed that in spite of proper design and construction of the ventilation system, unfavorable microclimatic conditions that differed from the predicted ones caused significant reduction in the efficiency of the ventilation system. Also, during some time periods, external climate conditions caused an opposite air flow direction in the vent inlets and outlets, leading to a significant deterioration of air quality and thermal comfort measured by CO2 concentration and PMV index in a residential area.

Looking Deeper Into Hydrologic Connectivity and Streamflow Generation: A Groundwater Hydrologist's Perspective.

NASA Astrophysics Data System (ADS)

Gardner, W. P.

2016-12-01

In this presentation the definition of hydraulic connection will be explored with a focus on the role of deep groundwater in streamflow generation and its time and space limits. Regional groundwater flow paths can be important sources of baseflow and potentially event response in surface water systems. This deep groundwater discharge plays an important role in determining how the watershed responds to climatic forcing, whether watersheds are a carbon source or sink and can be significant for watershed geochemistry and nutrient loading. These flow paths potentially "connect" to surface water systems and saturated soil zones at large distances, and over long time scales. However, these flow paths are challenging to detect, especially with hydraulic techniques. Here we will discuss some of the basic physical processes that affect the hydraulic signal along a groundwater flow path and their implications for the definition of hydrologic connection. Methods of measuring hydraulic connection using groundwater head response and their application in detecting regional groundwater discharge will be discussed. Environmental tracers are also a powerful method for identifying connected flowpaths in groundwater systems, and are commonly used to determine flow connection and flow rates in groundwater studies. Isotopic tracer methods for detecting deep, regional flow paths in watersheds will be discussed, along with observations of deep groundwater discharge in shallow alluvial systems around the world. The goal of this talk is to discuss hydraulic and hydrologic connection from a groundwater hydrologist's perspective, spark conversation on the meaning of hydrologic connection, the processes which govern hydraulic response and methods to measure flow connections and flux.

Direct process estimation from tomographic data using artificial neural systems

NASA Astrophysics Data System (ADS)

Mohamad-Saleh, Junita; Hoyle, Brian S.; Podd, Frank J.; Spink, D. M.

2001-07-01

The paper deals with the goal of component fraction estimation in multicomponent flows, a critical measurement in many processes. Electrical capacitance tomography (ECT) is a well-researched sensing technique for this task, due to its low-cost, non-intrusion, and fast response. However, typical systems, which include practicable real-time reconstruction algorithms, give inaccurate results, and existing approaches to direct component fraction measurement are flow-regime dependent. In the investigation described, an artificial neural network approach is used to directly estimate the component fractions in gas-oil, gas-water, and gas-oil-water flows from ECT measurements. A 2D finite- element electric field model of a 12-electrode ECT sensor is used to simulate ECT measurements of various flow conditions. The raw measurements are reduced to a mutually independent set using principal components analysis and used with their corresponding component fractions to train multilayer feed-forward neural networks (MLFFNNs). The trained MLFFNNs are tested with patterns consisting of unlearned ECT simulated and plant measurements. Results included in the paper have a mean absolute error of less than 1% for the estimation of various multicomponent fractions of the permittivity distribution. They are also shown to give improved component fraction estimation compared to a well known direct ECT method.

Recent modifications and calibration of the Langley low-turbulence pressure tunnel

NASA Technical Reports Server (NTRS)

Mcghee, R. J.; Beasley, W. D.; Foster, J. M.

1984-01-01

Modifications to the Langley Low-Turbulence Pressure Tunnel are presented and a calibration of the mean flow parameters in the test section is provided. Also included are the operational capability of the tunnel and typical test results for both single-element and multi-element airfoils. Modifications to the facility consisted of the following: replacement of the original cooling coils and antiturbulence screens and addition of a tunnel-shell heating system, a two dimensional model-support and force-balance system, a sidewall boundary layer control system, a remote-controlled survey apparatus, and a new data acquisition system. A calibration of the mean flow parameters in the test section was conducted over the complete operational range of the tunnel. The calibration included dynamic-pressure measurements, Mach number distributions, flow-angularity measurements, boundary-layer characteristics, and total-pressure profiles. In addition, test-section turbulence measurements made after the tunnel modifications have been included with these calibration data to show a comparison of existing turbulence levels with data obtained for the facility in 1941 with the original screen installation.

Statistical Properties of Lorenz-like Flows, Recent Developments and Perspectives

NASA Astrophysics Data System (ADS)

Araujo, Vitor; Galatolo, Stefano; Pacifico, Maria José

We comment on the mathematical results about the statistical behavior of Lorenz equations and its attractor, and more generally on the class of singular hyperbolic systems. The mathematical theory of such kind of systems turned out to be surprisingly difficult. It is remarkable that a rigorous proof of the existence of the Lorenz attractor was presented only around the year 2000 with a computer-assisted proof together with an extension of the hyperbolic theory developed to encompass attractors robustly containing equilibria. We present some of the main results on the statistical behavior of such systems. We show that for attractors of three-dimensional flows, robust chaotic behavior is equivalent to the existence of certain hyperbolic structures, known as singular-hyperbolicity. These structures, in turn, are associated with the existence of physical measures: in low dimensions, robust chaotic behavior for flows ensures the existence of a physical measure. We then give more details on recent results on the dynamics of singular-hyperbolic (Lorenz-like) attractors: (1) there exists an invariant foliation whose leaves are forward contracted by the flow (and further properties which are useful to understand the statistical properties of the dynamics); (2) there exists a positive Lyapunov exponent at every orbit; (3) there is a unique physical measure whose support is the whole attractor and which is the equilibrium state with respect to the center-unstable Jacobian; (4) this measure is exact dimensional; (5) the induced measure on a suitable family of cross-sections has exponential decay of correlations for Lipschitz observables with respect to a suitable Poincaré return time map; (6) the hitting time associated to Lorenz-like attractors satisfy a logarithm law; (7) the geometric Lorenz flow satisfies the Almost Sure Invariance Principle (ASIP) and the Central Limit Theorem (CLT); (8) the rate of decay of large deviations for the volume measure on the ergodic basin of a geometric Lorenz attractor is exponential; (9) a class of geometric Lorenz flows exhibits robust exponential decay of correlations; (10) all geometric Lorenz flows are rapidly mixing and their time-1 map satisfies both ASIP and CLT.

Improvements in Low-cost Ultrasonic Measurements of Blood Flow in "by-passes" Using Narrow & Broad Band Transit-time Procedures

NASA Astrophysics Data System (ADS)

Ramos, A.; Calas, H.; Diez, L.; Moreno, E.; Prohías, J.; Villar, A.; Carrillo, E.; Jiménez, A.; Pereira, W. C. A.; Von Krüger, M. A.

The cardio-pathology by ischemia is an important cause of death, but the re-vascularization of coronary arteries (by-pass operation) is an useful solution to reduce associated morbidity improving quality of life in patients. During these surgeries, the flow in coronary vessels must be measured, using non-invasive ultrasonic methods, known as transit time flow measurements (TTFM), which are the most accurate option nowadays. TTFM is a common intra-operative tool, in conjunction with classic Doppler velocimetry, to check the quality of these surgery processes for implanting grafts in parallel with the coronary arteries. This work shows important improvements achieved in flow-metering, obtained in our research laboratories (CSIC, ICIMAF, COPPE) and tested under real surgical conditions in Cardiocentro-HHA, for both narrowband NB and broadband BB regimes, by applying results of a CYTED multinational project (Ultrasonic & computational systems for cardiovascular diagnostics). mathematical models and phantoms were created to evaluate accurately flow measurements, in laboratory conditions, before our new electronic designs and low-cost implementations, improving previous ttfm systems, which include analogic detection, acquisition & post-processing, and a portable PC. Both regimes (NB and BB), with complementary performances for different conditions, were considered. Finally, specific software was developed to offer facilities to surgeons in their interventions.

Compact 3D Camera for Shake-the-Box Particle Tracking

NASA Astrophysics Data System (ADS)

Hesseling, Christina; Michaelis, Dirk; Schneiders, Jan

2017-11-01

Time-resolved 3D-particle tracking usually requires the time-consuming optical setup and calibration of 3 to 4 cameras. Here, a compact four-camera housing has been developed. The performance of the system using Shake-the-Box processing (Schanz et al. 2016) is characterized. It is shown that the stereo-base is large enough for sensible 3D velocity measurements. Results from successful experiments in water flows using LED illumination are presented. For large-scale wind tunnel measurements, an even more compact version of the system is mounted on a robotic arm. Once calibrated for a specific measurement volume, the necessity for recalibration is eliminated even when the system moves around. Co-axial illumination is provided through an optical fiber in the middle of the housing, illuminating the full measurement volume from one viewing direction. Helium-filled soap bubbles are used to ensure sufficient particle image intensity. This way, the measurement probe can be moved around complex 3D-objects. By automatic scanning and stitching of recorded particle tracks, the detailed time-averaged flow field of a full volume of cubic meters in size is recorded and processed. Results from an experiment at TU-Delft of the flow field around a cyclist are shown.

Characteristics of Flow Past Fuselages and Wing-Fuselage Systems of Gliders

NASA Technical Reports Server (NTRS)

Ostrowski, Jerzy; Litwinczyk, Mieczyslaw; Turkowski, Lukasz

1980-01-01

The results are presented for visualization tests and measurements of the velocity field in diffusion regions (with a positive pressure gradient) for fuselages and transition regions between the wing and the fuselage. Wind tunnel and flight tests were performed. Specific emphasis was placed on examining the secondary flow influencing separation acceleration and the influence of the geometrical form of the wing fuselage system manifested by the occurrence of secondary flows of various types.

Thermal heat-balance mode flow-to-frequency converter

NASA Astrophysics Data System (ADS)

Pawlowski, Eligiusz

2016-11-01

This paper presents new type of thermal flow converter with the pulse frequency output. The integrating properties of the temperature sensor have been used, which allowed for realization of pulse frequency modulator with thermal feedback loop, stabilizing temperature of sensor placed in the flowing medium. The system assures balancing of heat amount supplied in impulses to the sensor and heat given up by the sensor in a continuous way to the flowing medium. Therefore the frequency of output impulses is proportional to the heat transfer coefficient from sensor to environment. According to the King's law, the frequency of those impulses is a function of medium flow velocity around the sensor. The special feature of presented solution is total integration of thermal sensor with the measurement signal conditioning system. Sensor and conditioning system are not the separate elements of the measurement circuit, but constitute a whole in form of thermal heat-balance mode flow-to-frequency converter. The advantage of such system is easiness of converting the frequency signal to the digital form, without using any additional analogue-to-digital converters. The frequency signal from the converter may be directly connected to the microprocessor input, which with use of standard built-in counters may convert the frequency into numerical value of high precision. Moreover, the frequency signal has higher resistance to interference than the voltage signal and may be transmitted to remote locations without the information loss.

Usage of CO2 microbubbles as flow-tracing contrast media in X-ray dynamic imaging of blood flows.

PubMed

Lee, Sang Joon; Park, Han Wook; Jung, Sung Yong

2014-09-01

X-ray imaging techniques have been employed to visualize various biofluid flow phenomena in a non-destructive manner. X-ray particle image velocimetry (PIV) was developed to measure velocity fields of blood flows to obtain hemodynamic information. A time-resolved X-ray PIV technique that is capable of measuring the velocity fields of blood flows under real physiological conditions was recently developed. However, technical limitations still remained in the measurement of blood flows with high image contrast and sufficient biocapability. In this study, CO2 microbubbles as flow-tracing contrast media for X-ray PIV measurements of biofluid flows was developed. Human serum albumin and CO2 gas were mechanically agitated to fabricate CO2 microbubbles. The optimal fabricating conditions of CO2 microbubbles were found by comparing the size and amount of microbubbles fabricated under various operating conditions. The average size and quantity of CO2 microbubbles were measured by using a synchrotron X-ray imaging technique with a high spatial resolution. The quantity and size of the fabricated microbubbles decrease with increasing speed and operation time of the mechanical agitation. The feasibility of CO2 microbubbles as a flow-tracing contrast media was checked for a 40% hematocrit blood flow. Particle images of the blood flow were consecutively captured by the time-resolved X-ray PIV system to obtain velocity field information of the flow. The experimental results were compared with a theoretically amassed velocity profile. Results show that the CO2 microbubbles can be used as effective flow-tracing contrast media in X-ray PIV experiments.

Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography

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

Lin Mingde; Marshall, Craig T.; Qi, Yi

Purpose: The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations--they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, aremore » invasive, or require euthanasia. Methods: In this study, high-spatial and high-temporal resolution x-ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel-by-pixel basis (100x100 {mu}m{sup 2}). Results: A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer-344 rats was found to be 37.0{+-}5.1 ml/min. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be 18.90xCO{sub DSA}=CO{sub Fick}. Conclusions: This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.« less

Measuring mountain river discharge using seismographs emplaced within the hyporheic zone

Treesearch

R. E. Anthony; R. C. Aster; S. Ryan; S. Rathburn; M. G. Baker

2018-01-01

Flow and sediment transport dynamics in fluvial systems play critical roles in shaping river morphology, in the design and use of riverine infrastructure, and in the broader management of watersheds. However, these properties are often difficult to measure comprehensively. Previous work has suggested the use of proximal seismic signals resulting from flow and bed load...

Surface Composition Influence on Internal Gas Flow at Large Knudsen Numbers

DTIC Science & Technology

2000-07-09

situated in an ultra high vacuum system . The system is supplied with means of gas phase, surface CP585, Rarefied Gas Dynamics: 22nd International...control and gas flow measuring system . The experimental procedure consists in a few stages. The first stage includes surface preparation process at...solid body system , Proceedings 20-th Int. Symp. Rarefied Gas Dynamics, Peking University Press, Beijing, China, 1997, pp. 387-391. 3. Lord, R.G

Explorations of electric current system in solar active regions. I - Empirical inferences of the current flows

NASA Technical Reports Server (NTRS)

Ding, Y. J.; Hong, Q. F.; Hagyard, M. J.; Deloach, A. C.; Liu, X. P.

1987-01-01

Techniques to identify sources of electric current systems and their channels of flow in solar active regions are explored. Measured photospheric vector magnetic fields together with high-resolution white-light and H-alpha filtergrams provide the data base to derive the current systems in the photosphere and chromosphere. As an example, the techniques are then applied to infer current systems in AR 2372 in early April 1980.

L.D.V. measurements of unsteady flow fields in radial turbine

NASA Astrophysics Data System (ADS)

Tabakoff, W.; Pasin, M.

1992-07-01

Detailed measurements of an unsteady flow field within the inlet guide vanes (IGV) and the rotor of a radial inflow turbine were performed using a three component Laser Doppler Velocimeter (LDV) system together with a rotary encoder. The mean velocity, the flow angle and the turbulence contours for IGV passages are presented at four blade-to-blade planes for different rotor positions to give three dimensional, unsteady behavior of the IGV flow field. These results are compared with the measurements obtained in the same passage in the absence of the rotor. The flow field of the IGV passage was found to be affected by the presence of the rotor. The ratio of the tangential normal stresses to the radial normal stresses at the exit of the IGV was found to be more than doubled when compared to the case without the rotor. The rotor flow field measurements are presented as relative mean velocity and turbulence stress contours at various cross section planes throughout the rotor. The cross flow and turbulence stress levels were found to be influenced by the incidence angle. Transportation of the high turbulence fluid by the cross flow was observed downstream in the rotor blade passages.

Increased resistance of hygroscopic condenser humidifiers when using a closed circuit suction system.

PubMed

Martinez, F J; Pietchel, S; Wise, C; Walek, J; Beamis, J F

1994-10-01

To examine a hygroscopic condenser after clinical use and to describe the interaction of a hygroscopic condenser and a closed circuit suction system used simultaneously. Prospective evaluation of hygroscopic condensers used clinically, and laboratory investigation of a hygroscopic condenser used with a closed circuit suction system. Tertiary referral centers. The hygroscopic condenser used during mechanical ventilation was removed and peak inflation pressure was measured by delivering a standard tidal volume and inspiratory flow across the isolated hygroscopic condenser while recording the peak inflation pressure. In the laboratory, four 10-mL aliquots of saline were instilled via closed circuit suction system into a test lung with fresh hygroscopic condensers (n = 15) inline. At baseline and after each instillation, the hygroscopic condenser was weighed and the peak inflation pressure was measured while in five condensers, peak expiratory flow rate was also measured. In these five devices, hygroscopic condenser resistance was measured with 100 L/min of constant gas flow while measuring the pressure drop across the hygroscopic condenser. In 11 hygroscopic condensers used for 27.5 +/- 11.9 hrs with no closed circuit suction system, the peak inflation pressure was 3.74 +/- 0.58 cm H2O. In the laboratory, instillation of saline via closed circuit suction system was associated with an increase in hygroscopic condenser weight. Peak inflation pressure increased in a quadratic fashion with the increase in hygroscopic condenser weight, while peak expiratory flow rate decreased in a linear fashion. After four saline instillations, hygroscopic condenser resistance increased from 5.66 +/- 0.31 to 13.9 +/- 2.42 cm H2O/L/sec. Clinical use of a hygroscopic condenser alone is not associated with a significant increase in peak inflation pressure. We caution the use of a hygroscopic condenser and a closed circuit suction system simultaneously, as an increase in hygroscopic condenser resistance may develop and may be poorly tolerated in patients with marginal ventilatory reserve.

Interfacial Area Development in Two-Phase Fluid Flow: Transient vs. Quasi-Static Flow Conditions

NASA Astrophysics Data System (ADS)

Meisenheimer, D. E.; Wildenschild, D.

2017-12-01

Fluid-fluid interfaces are important in multiphase flow systems in the environment (e.g. groundwater remediation, geologic CO2 sequestration) and industry (e.g. air stripping, fuel cells). Interfacial area controls mass transfer, and therefore reaction efficiency, between the different phases in these systems but they also influence fluid flow processes. There is a need to better understand this relationship between interfacial area and fluid flow processes so that more robust theories and models can be built for engineers and policy makers to improve the efficacy of many multiphase flow systems important to society. Two-phase flow experiments were performed in glass bead packs under transient and quasi-static flow conditions. Specific interfacial area was calculated from 3D images of the porous media obtained using the fast x-ray microtomography capability at the Advanced Photon Source. We present data suggesting a direct relationship between the transient nature of the fluid-flow experiment (fewer equilibrium points) and increased specific interfacial area. The effect of flow condition on Euler characteristic (a representative measure of fluid topology) will also be presented.

In vivo flow speed measurement of capillaries by photoacoustic correlation spectroscopy.

PubMed

Chen, Sung-Liang; Xie, Zhixing; Carson, Paul L; Wang, Xueding; Guo, L Jay

2011-10-15

We recently proposed photoacoustic correlation spectroscopy (PACS) and demonstrated a proof-of-concept experiment. Here we use the technique for in vivo flow speed measurement in capillaries in a chick embryo model. The photoacoustic microscopy system is used to render high spatial resolution and high sensitivity, enabling sufficient signals from single red blood cells. The probe beam size is calibrated by a blood-mimicking phantom. The results indicate the feasibility of using PACS to study flow speeds in capillaries.

Elliptic flow in Au+Au collisions at RHIC

NASA Astrophysics Data System (ADS)

Vale, Carla M.; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Ngyuen, M.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.

2005-04-01

Elliptic flow is an interesting probe of the dynamical evolution of the dense system formed in the ultrarelativistic heavy ion collisions at the relativistic heavy ion collider (RHIC). The elliptic flow dependences on transverse momentum, centrality and pseudorapidity were measured using data collected by the PHOBOS detector, which offers a unique opportunity to study the azimuthal anisotropies of charged particles over a wide range of pseudorapidity. These measurements are presented, together with an overview of the analysis methods and a discussion of the results.

Computer assisted uroflowmetry diagnostic system

NASA Astrophysics Data System (ADS)

Makal, Jarosław; Idźkowski, Adam; Walendziuk, Wojciech

2006-10-01

In this paper an original uroflowmeter (called Adalbertus) has been presented. The device draws the flow chart and measures the parameters of urine flow. It is used in urological surgeries as an assistance in diagnosis of lower urinary track diseases like Benign Prostatic Hyperplasia (BPH). The measuring track and its main part - weight sensor have been described. Also the way of uncertainty calculation is mentioned. An example flow chart has been shown and the achieved results have been compared with a commercial product.

Laser transit anemometer measurements of a JANNAF nozzle base velocity flow field

NASA Technical Reports Server (NTRS)

Hunter, William W., Jr.; Russ, C. E., Jr.; Clemmons, J. I., Jr.

1990-01-01

Velocity flow fields of a nozzle jet exhausting into a supersonic flow were surveyed. The measurements were obtained with a laser transit anemometer (LTA) system in the time domain with a correlation instrument. The LTA data is transformed into the velocity domain to remove the error that occurs when the data is analyzed in the time domain. The final data is shown in velocity vector plots for positions upstream, downstream, and in the exhaust plane of the jet nozzle.

System and method for bidirectional flow and controlling fluid flow in a conduit

DOEpatents

Ortiz, M.G.

1999-03-23

A system for measuring bidirectional flow, including backflow, of fluid in a conduit is disclosed. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit. 3 figs.

The application of improved flow diverter for first flush management.

PubMed

Mrowiec, M

2010-01-01

The paper presents the investigations on first flush phenomenon based on the total suspended solids (TSS) concentration measurement during selected rainfalls at central part of Czestochowa (Poland) and also the hydrodynamic model of the catchment. The model allows to present the conception of first flush management using an improved flow diverter Septurn. Flow diverters used in the separate sewer systems create a hybrid system called "semi-separate" sewage system, which allows to treat the first flush volume in the waste water treatment plant (WWTP). Proposed construction of the flow diverter makes possible to capture significant part of the pollutant load (TSS) and simultaneously to reduce volume discharges to WWTPs during wet weather.

Hemodynamic Responses to Head and Neck Cooling

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Carbo, Jorge E.; Montgomery, Leslie D.; Webbon, Bruce W.

1994-01-01

Personal thermoregulatory systems which provide head and neck cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objective of this study was to measure the scalp temperature and circulatory responses during use of one commercially available thermal control system. The Life Support Systems, Inc. Mark VII portable cooling system and a liquid cooling helmet were used in this study. Two EEG electrodes and one skin temperature transducer were placed on the anterior midline of the scalp to measure the scalp blood and temperature. Blood flow was measured using a bipolar impedance rheograph. Ten subjects, seated in an upright position at normal room temperature, were tested at high, medium, moderate, moderate-low and low coolant temperatures. Scalp blood flow was recorded continuously using a computer data acquisition system with a sampling frequency of 200 Hz. Scalp temperature and cooling helmet Inlet temperature was logged periodically during the test period. This study quantifies the effect of head cooling upon scalp temperature and blood flow. These data may also be used to select operational specifications of the head cooling system for biomedical applications such as the treatment of migraine headaches, scalp cooling during chemotherapy, and cooling of multiple sclerosis patients.

Ultrasound Flow Mapping for the Investigation of Crystal Growth.

PubMed

Thieme, Norman; Bonisch, Paul; Meier, Dagmar; Nauber, Richard; Buttner, Lars; Dadzis, Kaspars; Patzold, Olf; Sylla, Lamine; Czarske, Jurgen

2017-04-01

A high energy conversion and cost efficiency are keys for the transition to renewable energy sources, e.g., solar cells. The efficiency of multicrystalline solar cells can be improved by enhancing the understanding of its crystallization process, especially the directional solidification. In this paper, a novel measurement system for the characterization of flow phenomena and solidification processes in low-temperature model experiments on the basis of ultrasound (US) Doppler velocimetry is described. It captures turbulent flow phenomena in two planes with a frame rate of 3.5 Hz and tracks the shape of the solid-liquid interface during multihour experiments. Time-resolved flow mapping is performed using four linear US arrays with a total of 168 transducer elements. Long duration measurements are enabled through an online, field-programmable gate array (FPGA)-based signal processing. Nine single US transducers allow for in situ tracking of a solid-liquid interface. Results of flow and solidification experiments in the model experiment are presented and compared with numerical simulation. The potential of the developed US system for measuring turbulent flows and for tracking the solidification front during a directional crystallization process is demonstrated. The results of the model experiments are in good agreement with numerical calculations and can be used for the validation of numerical models, especially the selection of the turbulence model.

Packaged peristaltic micropump for controlled drug delivery application

NASA Astrophysics Data System (ADS)

Vinayakumar, K. B.; Nadiger, Girish; R. Shetty, Vikas; Dinesh, N. S.; Nayak, M. M.; Rajanna, K.

2017-01-01

Micropump technology has evolved significantly in the last two decades and is finding a variety of applications ranging from μTAS (micro Total Analysis System) to drug delivery. However, the application area of the micropump is limited owing to: simple pumping mechanism, ease of handling, controlled (microliter to milliliter) delivery, continuous delivery, and accuracy in flow rate. Here, the author presents the design, development, characterization, and precision flow controlling of a DC-motor driven peristaltic pump for controlled drug delivery application. All the micropump components were fabricated using the conventional fabrication technique. The volume flow variation of the pump has been characterized for different viscous fluids. The change in volume flow due to change in back pressure has been presented in detail. The fail-safe mode operation of the pump has been tested and leak rate was measured (˜0.14% leak for an inlet pressure of 140 kPa) for different inlet pressures. The precision volume flow of the pump has been achieved by measuring the pinch cam position and load current. The accuracy in the volume flow has been measured after 300 rotations. Finally, the complete system has been integrated with the necessary electronics and an android application has been developed for the self-administration of bolus and basal delivery of insulin.

In-line pressure-flow module for in vitro modelling of haemodynamics and biosensor validation

NASA Technical Reports Server (NTRS)

Koenig, S. C.; Schaub, J. D.; Ewert, D. L.; Swope, R. D.; Convertino, V. A. (Principal Investigator)

1997-01-01

An in-line pressure-flow module for in vitro modelling of haemodynamics and biosensor validation has been developed. Studies show that good accuracy can be achieved in the measurement of pressure and of flow, in steady and pulstile flow systems. The model can be used for development, testing and evaluation of cardiovascular-mechanical-electrical anlogue models, cardiovascular prosthetics (i.e. valves, vascular grafts) and pressure and flow biosensors.

Experimental and analytical dynamic flow characteristics of an axial-flow fan from an air cushion landing system model

NASA Technical Reports Server (NTRS)

Thompson, W. C.; Boghani, A. B.; Leland, T. J. W.

1977-01-01

An investigation was conducted to compare the steady-state and dynamic flow characteristics of an axial-flow fan which had been used previously as the air supply fan for some model air cushion landing system studies. Steady-state flow characteristics were determined in the standard manner by using differential orifice pressures for the flow regime from free flow to zero flow. In this same regime, a correlative technique was established so that fan inlet and outlet pressures could be used to measure dynamic flow as created by a rotating damper. Dynamic tests at damper frequencies up to 5 Hz showed very different flow characteristics when compared with steady-state flow, particularly with respect to peak pressures and the pressure-flow relationship at fan stall and unstall. A generalized, rational mathematical fan model was developed based on physical fan parameters and a steady-state flow characteristic. The model showed good correlation with experimental tests at damper frequencies up to 5 Hz.

Dynamic properties of hot-wire anemometric measurement circuits in the aspect of measurements in mine conditions / Właściwości dynamiczne termoanemometrycznych układów pomiarowych w aspekcie pomiarów w warunkach kopalnianych

NASA Astrophysics Data System (ADS)

Jamróz, Paweł; Ligęza, Paweł; Socha, Katarzyna

2012-12-01

The use of measurement apparatus under conditions which differ significantly from those under which the apparatus was adjusted carries the risk of altering the previously determined measurement characteristics. This is of special concern in the case of apparatus which is sensitive to external measurement conditions. Advanced measurement systems are equipped with algorithms which allow the negative effect of unstable environmental conditions on their static characteristics to be compensated for. Meanwhile, the problem of altered dynamic properties of such systems is often neglected. This paper presents a model study in which the effect of variable operational conditions on dynamic response of hot-wire anemometric measurement system in the case of simulated mine flows was investigated. A mathematical model of measurement system able to compensate the negative effect of changes in flow velocity and configuration of measurement apparatus itself on its dynamic properties was developed and investigated. Based on conducted experiments, we have developed an automatic regulation algorithm enabling the transmission band of measurement apparatus to be optimized for measurement conditions prevailing in mine environment.

40 CFR 1065.225 - Intake-air flow meter.

Code of Federal Regulations, 2012 CFR

2012-07-01

... concentrations, if the same signal is used in a chemical-balance calculation to determine work from brake... tube, or a hot-wire anemometer. Note that your overall system for measuring intake-air flow must meet...

Development and validation of chemistry agnostic flow battery cost performance model and application to nonaqueous electrolyte systems: Chemistry agnostic flow battery cost performance model

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

Crawford, Alasdair; Thomsen, Edwin; Reed, David

2016-04-20

A chemistry agnostic cost performance model is described for a nonaqueous flow battery. The model predicts flow battery performance by estimating the active reaction zone thickness at each electrode as a function of current density, state of charge, and flow rate using measured data for electrode kinetics, electrolyte conductivity, and electrode-specific surface area. Validation of the model is conducted using a 4kW stack data at various current densities and flow rates. This model is used to estimate the performance of a nonaqueous flow battery with electrode and electrolyte properties used from the literature. The optimized cost for this system ismore » estimated for various power and energy levels using component costs provided by vendors. The model allows optimization of design parameters such as electrode thickness, area, flow path design, and operating parameters such as power density, flow rate, and operating SOC range for various application duty cycles. A parametric analysis is done to identify components and electrode/electrolyte properties with the highest impact on system cost for various application durations. A pathway to 100$kWh -1 for the storage system is identified.« less

[Feasibility Study on Digital Signal Processor and Gear Pump of Uroflowmeter Calibration Device].

PubMed

Yuan, Qing; Ji, Jun; Gao, Jiashuo; Wang, Lixin; Xiao, Hong

2016-08-01

It will cause hidden trouble on clinical application if the uroflowmeter is out of control.This paper introduces a scheme of uroflowmeter calibration device based on digital signal processor(DSP)and gear pump and shows studies of its feasibility.According to the research plan,we analyzed its stability,repeatability and linearity by building a testing system and carried out experiments on it.The flow test system is composed of DSP,gear pump and other components.The test results showed that the system could produce a stable water flow with high precision of repeated measurement and different flow rate.The test system can calibrate the urine flow rate well within the range of 9~50mL/s which has clinical significance,and the flow error is less than 1%,which meets the technical requirements of the calibration apparatus.The research scheme of uroflowmeter calibration device on DSP and gear pump is feasible.

Time Resolved PIV for Space-Time Correlations in Hot Jets

NASA Technical Reports Server (NTRS)

Wernet, Mark P.

2007-01-01

Temporally Resolved Particle Image Velocimetry (TR-PIV) is the newest and most exciting tool recently developed to support our continuing efforts to characterize and improve our understanding of the decay of turbulence in jet flows -- a critical element for understanding the acoustic properties of the flow. A new TR-PIV system has been developed at the NASA Glenn Research Center which is capable of acquiring planar PIV image frame pairs at up to 25 kHz. The data reported here were collected at Mach numbers of 0.5 and 0.9 and at temperature ratios of 0.89 and 1.76. The field of view of the TR-PIV system covered 6 nozzle diameters along the lip line of the 50.8 mm diameter jet. The cold flow data at Mach 0.5 were compared with hotwire anemometry measurements in order to validate the new TR-PIV technique. The axial turbulence profiles measured across the shear layer using TR-PIV were thinner than those measured using hotwire anemometry and remained centered along the nozzle lip line. The collected TR-PIV data illustrate the differences in the single point statistical flow properties of cold and hot jet flows. The planar, time-resolved velocity records were then used to compute two-point space-time correlations of the flow at the Mach 0.9 flow condition. The TR-PIV results show that there are differences in the convective velocity and growth rate of the turbulent structures between cold and hot flows at the same Mach number

Migration Systems in Europe: Evidence From Harmonized Flow Data

PubMed Central

Kim, Keuntae; Raymer, James

2014-01-01

Empirical tests of migration systems theory require consistent and complete data on international migration flows. Publicly available data, however, represent an inconsistent and incomplete set of measurements obtained from a variety of national data collection systems. We overcome these obstacles by standardizing the available migration reports of sending and receiving countries in the European Union and Norway each year from 2003–2007 and by estimating the remaining missing flows. The resulting harmonized estimates are then used to test migration systems theory. First, locating thresholds in the size of flows over time, we identify three migration systems within the European Union and Norway. Second, examining the key determinants of flows with respect to the predictions of migration systems theory, our results highlight the importance of shared experiences of nation-state formation, geography, and accession status in the European Union. Our findings lend support to migration systems theory and demonstrate that knowledge of migration systems may improve the accuracy of migration forecasts toward managing the impacts of migration as a source of social change in Europe. PMID:22791267

Discharge measurements using a broad-band acoustic Doppler current profiler

USGS Publications Warehouse

Simpson, Michael R.

2002-01-01

The measurement of unsteady or tidally affected flow has been a problem faced by hydrologists for many years. Dynamic discharge conditions impose an unreasonably short time constraint on conventional current-meter discharge-measurement methods, which typically last a minimum of 1 hour. Tidally affected discharge can change more than 100 percent during a 10-minute period. Over the years, the U.S. Geological Survey (USGS) has developed moving-boat discharge-measurement techniques that are much faster but less accurate than conventional methods. For a bibliography of conventional moving-boat publications, see Simpson and Oltmann (1993, page 17). The advent of the acoustic Doppler current profiler (ADCP) made possible the development of a discharge-measurement system capable of more accurately measuring unsteady or tidally affected flow. In most cases, an ADCP discharge-measurement system is dramatically faster than conventional discharge-measurement systems, and has comparable or better accuracy. In many cases, an ADCP discharge-measurement system is the only choice for use at a particular measurement site. ADCP systems are not yet ?turnkey;? they are still under development, and for proper operation, require a significant amount of operator training. Not only must the operator have a rudimentary knowledge of acoustic physics, but also a working knowledge of ADCP operation, the manufacturer's discharge-measurement software, and boating techniques and safety.

VETA-1 x ray detection system

NASA Technical Reports Server (NTRS)

Podgorski, W. A.; Flanagan, Kathy A.; Freeman, Mark D.; Goddard, R. G.; Kellogg, Edwin M.; Norton, T. J.; Ouellette, J. P.; Roy, A. G.; Schwartz, Daniel A.

1992-01-01

The alignment and X-ray imaging performance of the Advanced X-ray Astrophysics Facility (AXAF) Verification Engineering Test Article-I (VETA-I) was measured by the VETA-I X-Ray Detection System (VXDS). The VXDS was based on the X-ray detection system utilized in the AXAF Technology Mirror Assembly (TMA) program, upgraded to meet the more stringent requirements of the VETA-I test program. The VXDS includes two types of X-ray detectors: (1) a High Resolution Imager (HRI) which provides X-ray imaging capabilities, and (2) sealed and flow proportional counters which, in conjunction with apertures of various types and precision translation stages, provide the most accurate measurement of VETA-I performance. Herein we give an overview of the VXDS hardware including X-ray detectors, translation stages, apertures, proportional counters and flow counter gas supply system and associated electronics. We also describe the installation of the VXDS into the Marshall Space Flight Center (MSFC) X-Ray Calibration Facility (XRCF). We discuss in detail the design and performance of those elements of the VXDS which have not been discussed elsewhere; translation systems, flow counter gas supply system, apertures and thermal monitoring system.

An LDA (Laser-Doppler Anemometry) investigation of three-dimensional normal shock wave boundary-layer interactions

NASA Technical Reports Server (NTRS)

Chriss, R. M.; Hingst, W. R.; Strazisar, A. J.; Keith, T. G., Jr.

1989-01-01

Nonintrusive measurements were made of a normal shock wave/boundary layer interaction. Two dimensional measurements were made throughout the interaction region while 3-D measurements were made in the vicinity of the shock wave. The measurements were made in the corner of the test section of a continuous supersonic wind tunnel in which a normal shock wave had been stabilized. Laser Doppler Anemometry, surface pressure measurement and flow visualization techniques were employed for two freestream Mach number test cases: 1.6 and 1.3. The former contained separated flow regions and a system of shock waves. The latter was found to be far less complicated. The results define the flow field structure in detail for each case.

Characterization of a Head-Only Aerosol Exposure System for Nonhuman Primates

DTIC Science & Technology

2010-01-01

Alicat Scientific). The flow used provided isokinetic sampling, assuming the presence of laminar flow at the filter inlet, so that the chamber...airflow measured at the chamber inlet using a Gilibrator flow meter (Sensidyne LP) was 29.79±0.88L/min (n= 10; CV=2.97%). With both the aerosol

40 CFR 1065.345 - Vacuum-side leak verification.

Code of Federal Regulations, 2011 CFR

2011-07-01

... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the.... Measure and record the absolute pressure of the trapped gas and optionally the system absolute temperature... pressure and optionally temperature. (4) Calculate the leak flow rate based on an assumed value of zero for...

40 CFR 1065.345 - Vacuum-side leak verification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the.... Measure and record the absolute pressure of the trapped gas and optionally the system absolute temperature... pressure and optionally temperature. (4) Calculate the leak flow rate based on an assumed value of zero for...

40 CFR 1065.345 - Vacuum-side leak verification.

Code of Federal Regulations, 2013 CFR

2013-07-01

... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the.... Measure and record the absolute pressure of the trapped gas and optionally the system absolute temperature... pressure and optionally temperature. (4) Calculate the leak flow rate based on an assumed value of zero for...

40 CFR 1065.345 - Vacuum-side leak verification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the.... Measure and record the absolute pressure of the trapped gas and optionally the system absolute temperature... pressure and optionally temperature. (4) Calculate the leak flow rate based on an assumed value of zero for...

40 CFR 1065.345 - Vacuum-side leak verification.

Code of Federal Regulations, 2012 CFR

2012-07-01

... zero flow, or by detecting the dilution of a known concentration of span gas when it flows through the.... Measure and record the absolute pressure of the trapped gas and optionally the system absolute temperature... pressure and optionally temperature. (4) Calculate the leak flow rate based on an assumed value of zero for...

Performance evaluation of photoacoustic oximetry imaging systems using a dynamic blood flow phantom with tunable oxygen saturation

NASA Astrophysics Data System (ADS)

Vogt, William C.; Zhou, Xuewen; Andriani, Rudy; Wear, Keith A.; Garra, Brian S.; Pfefer, Joshua

2018-02-01

Photoacoustic Imaging (PAI) is an emerging technology with strong potential for broad clinical applications from breast cancer detection to cerebral monitoring due to its ability to compute maps of blood oxygen saturation (SO2) distribution in deep tissues using multispectral imaging. However, no well-validated consensus test methods currently exist for evaluating oximetry-specific performance characteristics of PAI devices. We have developed a phantombased flow system capable of rapid SO2 adjustment to serve as a test bed for elucidation of factors impacting SO2 measurement and quantitative characterization of device performance. The flow system is comprised of a peristaltic pump, membrane oxygenator, oxygen and nitrogen gas, and in-line oxygen, pH, and temperature sensors that enable real-time estimation of SO2 reference values. Bovine blood was delivered through breast-relevant tissue phantoms containing vessel-mimicking fluid channels, which were imaged using a custom multispectral PAI system. Blood was periodically drawn for SO2 measurement in a clinical-grade CO-oximeter. We used this flow phantom system to evaluate the impact of device parameters (e.g.,wavelength-dependent fluence corrections) and tissue parameters (e.g. fluid channel depth, blood SO2, spectral coloring artifacts) on oximetry measurement accuracy. Results elucidated key challenges in PAI oximetry and device design trade-offs, which subsequently allowed for optimization of system performance. This approach provides a robust benchtop test platform that can support PAI oximetry device optimization, performance validation, and clinical translation, and may inform future development of consensus test methods for performance assessment of photoacoustic oximetry imaging systems.

Phase transition and flow-rate behavior of merging granular flows.

PubMed

Hu, Mao-Bin; Liu, Qi-Yi; Jiang, Rui; Hou, Meiying; Wu, Qing-Song

2015-02-01

Merging of granular flows is ubiquitous in industrial, mining, and geological processes. However, its behavior remains poorly understood. This paper studies the phase transition and flow-rate behavior of two granular flows merging into one channel. When the main channel is wider than the side channel, the system shows a remarkable two-sudden-drops phenomenon in the outflow rate when gradually increasing the main inflow. When gradually decreasing the main inflow, the system shows obvious hysteresis phenomenon. We study the flow-rate-drop phenomenon by measuring the area fraction and the mean velocity at the merging point. The phase diagram of the system is also presented to understand the occurrence of the phenomenon. We find that the dilute-to-dense transition occurs when the area fraction of particles at the joint point exceeds a critical value ϕ(c)=0.65±0.03.

Two-dimensional confocal laser scanning microscopy image correlation for nanoparticle flow velocimetry

NASA Astrophysics Data System (ADS)

Jun, Brian; Giarra, Matthew; Golz, Brian; Main, Russell; Vlachos, Pavlos

2016-11-01

We present a methodology to mitigate the major sources of error associated with two-dimensional confocal laser scanning microscopy (CLSM) images of nanoparticles flowing through a microfluidic channel. The correlation-based velocity measurements from CLSM images are subject to random error due to the Brownian motion of nanometer-sized tracer particles, and a bias error due to the formation of images by raster scanning. Here, we develop a novel ensemble phase correlation with dynamic optimal filter that maximizes the correlation strength, which diminishes the random error. In addition, we introduce an analytical model of CLSM measurement bias error correction due to two-dimensional image scanning of tracer particles. We tested our technique using both synthetic and experimental images of nanoparticles flowing through a microfluidic channel. We observed that our technique reduced the error by up to a factor of ten compared to ensemble standard cross correlation (SCC) for the images tested in the present work. Subsequently, we will assess our framework further, by interrogating nanoscale flow in the cell culture environment (transport within the lacunar-canalicular system) to demonstrate our ability to accurately resolve flow measurements in a biological system.

Flow cytometry without alignment of collection optics.

PubMed

Sitton, Greg; Srienc, Friedrich

2009-12-01

This study describes the performance of a new waveguide flow cell constructed from Teflon AF (TFC) and the potential use of fiber optic splitters to replace collection objectives and dichroic mirrors. The TFC has the unique optical property that the refractive index of the polymer is lower than water and therefore, water filled TFC behaves and functions as a liquid core waveguide. Thus, as cells flow through the TFC and are illuminated by a laser orthogonal to the flow direction, scattered and fluorescent light is directed down the axis of the TFC to a fiber optic. The total signal in the fiber optic is then split into multiple fibers by fiber optic splitters to enable measurement of signal intensities at different wavelengths. Optical filters are placed at the terminus of each fiber before measurement of specific wavelengths by a PMT. The constructed system was used to measure DNA content of CHO and yeast cells. Polystyrene beads were used for alignment and to assess the performance of the system. Polystyrene beads were observed to produce light scattering signals with unique bimodal characteristics dependent on the direction of flow relative to the collecting fiber optic.

Extraction of skin-friction fields from surface flow visualizations as an inverse problem

NASA Astrophysics Data System (ADS)

Liu, Tianshu

2013-12-01

Extraction of high-resolution skin-friction fields from surface flow visualization images as an inverse problem is discussed from a unified perspective. The surface flow visualizations used in this study are luminescent oil-film visualization and heat-transfer and mass-transfer visualizations with temperature- and pressure-sensitive paints (TSPs and PSPs). The theoretical foundations of these global methods are the thin-oil-film equation and the limiting forms of the energy- and mass-transport equations at a wall, which are projected onto the image plane to provide the relationships between a skin-friction field and the relevant quantities measured by using an imaging system. Since these equations can be re-cast in the same mathematical form as the optical flow equation, they can be solved by using the variational method in the image plane to extract relative or normalized skin-friction fields from images. Furthermore, in terms of instrumentation, essentially the same imaging system for measurements of luminescence can be used in these surface flow visualizations. Examples are given to demonstrate the applications of these methods in global skin-friction diagnostics of complex flows.

Laser two focus techniques

NASA Astrophysics Data System (ADS)

Schodl, R.

The development of the laser two focus velocimetry are reviewed. The fundamentals of this nonintrusive fluid flow velocity measurement technique are described. Emphasis is placed upon the advances of this technique. Results of measurements in a very small flow channel and in a small turbocharger compressor rotor are presented. The influence of beam diameter - beam separation ratio on the measuring accuracy and on the measuring time is treated. A multicolor two dimensional system with selectable beam separation is presented. The laser Doppler and the laser two focus techniques are compared.

An integrated laser trap/flow control video microscope for the study of single biomolecules.

PubMed Central

Wuite, G J; Davenport, R J; Rappaport, A; Bustamante, C

2000-01-01

We have developed an integrated laser trap/flow control video microscope for mechanical manipulation of single biopolymers. The instrument is automated to maximize experimental throughput. A single-beam optical trap capable of trapping micron-scale polystyrene beads in the middle of a 200-microm-deep microchamber is used, making it possible to insert a micropipette inside this chamber to hold a second bead by suction. Together, these beads function as easily exchangeable surfaces between which macromolecules of interest can be attached. A computer-controlled flow system is used to exchange the liquid in the chamber and to establish a flow rate with high precision. The flow and the optical trap can be used to exert forces on the beads, the displacements of which can be measured either by video microscopy or by laser deflection. To test the performance of this instrument, individual biotinylated DNA molecules were assembled between two streptavidin beads, and the DNA elasticity was characterized using both laser trap and flow forces. DNA extension under varying forces was measured by video microscopy. The combination of the flow system and video microscopy is a versatile design that is particularly useful for the study of systems susceptible to laser-induced damage. This capability was demonstrated by following the translocation of transcribing RNA polymerase up to 650 s. PMID:10920045

Solar hot water system installed at Mobile, Alabama

NASA Technical Reports Server (NTRS)

1980-01-01

The system consists of six rows of ten collectors and three rows of eleven collectors (1990 square feet) mounted on the roof. Griswald flow control valves were installed to regulate the flow to each row. Two Heliotrope electronic thermometers with a combined capability of measuring the temperatures of 22 different locations were installed for monitoring purposes.

Sensory Information Systems Program

DTIC Science & Technology

2012-03-06

cochlear implants. Developed by Dr. Les Atlas, U. Wash. Dr. Jay Rebenstein will develop commercial applications. TO: AFRL-- Eglin: Measurements and...wide field-of-view optic flow http://www.avl.umd.edu/ Microautonomous Systems and Technology Autonomous Steering: Transition to Army MAST 10...Wehling ( AFRL/RW): Neural analysis of optic flow . S. Sane ( Tata Institute): Insect multisensory integration 20 DISTRIBUTION A: Approved

Validity and reproducibility of electrical impedance tomography for measurement of calf blood flow in healthy subjects.

PubMed

Vonk Noordegraaf, A; Kunst, P W; Janse, A; Smulders, R A; Heethaar, R M; Postmus, P E; Faes, T J; de Vries, P M

1997-03-01

The Sheffield electrical impedance tomography; (EIT) system produces images of changes in the distribution of resistivity within tissue. The paper reports on the application of electrical impedance tomography in monitoring volume changes in the limb during venous occlusion. The aim of the study is to assess the feasibility, reproducibility and validity of calf blood flow measurements by EIT. In 14 healthy volunteers calf blood flow is compared, as determined in a calf segment by strain-gauge plethysmography (SGP), with the impedance changes measured by EIT during rest and post-ischaemic hyperaemia. The measurements are repeated to assess reproducibility. The reproducibility for the EIT, assessed from the repeated measurements and expressed as a reproducibility coefficient, is 0.88 during rest and 0.89 during hyperaemia. The reproducibility coefficient for SGP data is 0.83 at rest and 0.67 during hyperaemia. Flow measurements, assessed by means of two methods, correlate well at rest (r = 0.89), but only moderately during hyperaemia (r = 0.51). The correlation coefficient for the pooled flow measurements is 0.98. It is concluded that EIT is a valid and reliable method for assessing blood flow in the limb. Possible applications of EIT in localising fluid changes are discussed.

Definition of two-phase flow behaviors for spacecraft design

NASA Technical Reports Server (NTRS)

Reinarts, Thomas R.; Best, Frederick R.; Miller, Katherine M.; Hill, Wayne S.

1991-01-01

Data for complete models of two-phase flow in microgravity are taken from in-flight experiments and applied to an adiabatic flow-regime analysis to study the feasibility of two-phase systems for spacecraft. The data are taken from five in-flight experiments by Hill et al. (1990) in which a two-phase pump circulates a freon mixture and vapor and liquid flow streams are measured. Adiabatic flow regimes are analyzed based on the experimental superficial velocities of liquid and vapor, and comparisons are made with the results of two-phase flow regimes at 1 g. A motion analyzer records the flow characteristics at a rate of 1000 frames/sec, and stratified flow regimes are reported at 1 g. The flow regimes observed under microgravitational conditions are primarily annular and include slug and bubbly-slug regimes. The present data are of interest to the design and analysis of two-phase thermal-management systems for use in space missions.

The Presto 1000: A novel automated transcranial Doppler ultrasound system.

PubMed

Han, Seunggu J; Rutledge, William Caleb; Englot, Dario J; Winkler, Ethan A; Browne, Janet L; Pflugrath, Lauren; Cronsier, David; Abla, Adib A; Kliot, Michel; Lawton, Michael T

2015-11-01

We examined the reliability and ease of use of a novel automated transcranial Doppler (TCD) system in comparison to a conventional TCD system. TCD ultrasound allows non-invasive monitoring of cerebral blood flow, and can predict arterial vasospasm after a subarachnoid hemorrhage (SAH). The Presto 1000 TCD system (PhysioSonics, Bellevue, WA, USA) is designed for monitoring flow through the M1 segment of the middle cerebral artery (MCA) via temporal windows. The Presto 1000 system was tested across multiple preclinical and clinical settings in parallel with a control predicate TCD system. In a phantom flow generating device, both the Presto 1000 and Spencer system (Spencer Technologies, Redmond, WA, USA) were able to detect velocities with high accuracy. In nine volunteer patients, the Presto system was able to locate the MCA in 14 out of 18 temporal windows, in an average of 12.5s. In the SAH cohort of five patients with a total of 25 paired measurements, the mean absolute difference in flow velocities of the M1 segment, as measured by the two systems, was 17.5 cm/s. These data suggest that the Presto system offers an automated TCD that can reliably localize and detect flow of the MCA, with relative ease of use. The system carries the additional benefit of requiring minimal training for the operator, and can be used by many providers across multiple bedside settings. The mean velocities that were generated warrant further validation across an extended group of patients, and the predictive value for vasospasm should be checked against the current standard of angiography. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reducing misfocus-related motion artefacts in laser speckle contrast imaging.

PubMed

Ringuette, Dene; Sigal, Iliya; Gad, Raanan; Levi, Ofer

2015-01-01

Laser Speckle Contrast Imaging (LSCI) is a flexible, easy-to-implement technique for measuring blood flow speeds in-vivo. In order to obtain reliable quantitative data from LSCI the object must remain in the focal plane of the imaging system for the duration of the measurement session. However, since LSCI suffers from inherent frame-to-frame noise, it often requires a moving average filter to produce quantitative results. This frame-to-frame noise also makes the implementation of rapid autofocus system challenging. In this work, we demonstrate an autofocus method and system based on a novel measure of misfocus which serves as an accurate and noise-robust feedback mechanism. This measure of misfocus is shown to enable the localization of best focus with sub-depth-of-field sensitivity, yielding more accurate estimates of blood flow speeds and blood vessel diameters.

Study of Magnetic Damping Effect on Convection and Solidification Under G-Jitter Conditions

NASA Technical Reports Server (NTRS)

Li, Ben Q.; deGroh, H. C., III

1999-01-01

As shown by NASA resources dedicated to measuring residual gravity (SAMS and OARE systems), g-jitter is a critical issue affecting space experiments on solidification processing of materials. This study aims to provide, through extensive numerical simulations and ground based experiments, an assessment of the use of magnetic fields in combination with microgravity to reduce the g-jitter induced convective flows in space processing systems. We have so far completed asymptotic analyses based on the analytical solutions for g-jitter driven flow and magnetic field damping effects for a simple one-dimensional parallel plate configuration, and developed both 2-D and 3-D numerical models for g-jitter driven flows in simple solidification systems with and without presence of an applied magnetic field. Numerical models have been checked with the analytical solutions and have been applied to simulate the convective flows and mass transfer using both synthetic g-jitter functions and the g-jitter data taken from space flight. Some useful findings have been obtained from the analyses and the modeling results. Some key points may be summarized as follows: (1) the amplitude of the oscillating velocity decreases at a rate inversely proportional to the g-jitter frequency and with an increase in the applied magnetic field; (2) the induced flow approximately oscillates at the same frequency as the affecting g-jitter, but out of a phase angle; (3) the phase angle is a complicated function of geometry, applied magnetic field, temperature gradient and frequency; (4) g-jitter driven flows exhibit a complex fluid flow pattern evolving in time; (5) the damping effect is more effective for low frequency flows; and (6) the applied magnetic field helps to reduce the variation of solutal distribution along the solid-liquid interface. Work in progress includes numerical simulations and ground-based measurements. Both 2-D and 3-D numerical simulations are being continued to obtain further information on g-jitter driven flows and magnetic field effects. A physical model for ground-based measurements is completed and some measurements of the oscillating convection are being taken on the physical model. The comparison of the measurements with numerical simulations is in progress. Additional work planned in the project will also involve extending the 2-D numerical model to include the solidification phenomena with the presence of both g-jitter and magnetic fields.

System Size, Energy, Pseudorapidity, and Centrality Dependence of Elliptic Flow

NASA Astrophysics Data System (ADS)

Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Harnarine, I.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Richardson, E.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Szostak, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Willhelm, D.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wyngaardt, S.; Wysłouch, B.

2007-06-01

This Letter presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider. The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system.

Tracking, sensing and predicting flood wave propagation using nomadic satellite communication systems and hydrodynamic models

NASA Astrophysics Data System (ADS)

Hostache, R.; Matgen, P.; Giustarini, L.; Tailliez, C.; Iffly, J.-F.

2011-11-01

The main objective of this study is to contribute to the development and the improvement of flood forecasting systems. Since hydrometric stations are often poorly distributed for monitoring the propagation of extreme flood waves, the study aims at evaluating the hydrometric value of the Global Navigation Satellite System (GNSS). Integrated with satellite telecommunication systems, drifting or anchored floaters equipped with navigation systems such as GPS and Galileo, enable the quasi-continuous measurement and near real-time transmission of water level and flow velocity data, from virtually any point in the world. The presented study investigates the effect of assimilating GNSS-derived water level and flow velocity measurements into hydraulic models in order to reduce the associated predictive uncertainty.

Device and method for measuring the energy content of hot and humid air streams

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

Rosen, H. N.; Girod, G. F.; Kent, A. C.

1985-12-24

a portable device and method for measuring enthalpy and humidity of humid air from a space or flow channel at temperatures from 80/sup 0/ to 400/sup 0/ F. is described. the device consists of a psychrometer for measuring wet-bulb temperature, a vacuum pump for inducing sample air flow through the unit, a water-heating system for accurate psychrometer readings, an electronic computer system for evaluation of enthalpy and humidity from corrected and averaged values of wet- and dry- bulb temperatures, and a monitor for displaying the values. The device is programmable by the user to modify evaluation methods as necessary.

A New Approach to Sap Flow Measurement Using 3D Printed Gauges and Open-source Electronics

NASA Astrophysics Data System (ADS)

Ham, J. M.; Miner, G. L.; Kluitenberg, G. J.

2015-12-01

A new type of sap flow gauge was developed to measure transpiration from herbaceous plants using a modified heat pulse technique. Gauges were fabricated using 3D-printing technology and low-cost electronics to keep the materials cost under $20 (U.S.) per sensor. Each gauge consisted of small-diameter needle probes fastened to a 3D-printed frame. One needle contained a resistance heater to provide a 6 to 8 second heat pulse while the other probes measured the resultant temperature increase at two distances from the heat source. The data acquisition system for the gauges was built from a low-cost Arduino microcontroller. The system read the gauges every 10 minutes and stored the results on a SD card. Different numerical techniques were evaluated for estimating sap velocity from the heat pulse data - including analytical solutions and parameter estimation approaches . Prototype gauges were tested in the greenhouse on containerized corn and sunflower. Sap velocities measured by the gauges were compared to independent gravimetric measurements of whole plant transpiration. Results showed the system could measure daily transpiration to within 3% of the gravimetric measurements. Excellent agreement was observed when two gauges were attached the same stem. Accuracy was not affected by rapidly changing transpiration rates observed under partly cloudy conditions. The gauge-based estimates of stem thermal properties suggested the system may also detect the onset of water stress. A field study showed the gauges could run for 1 to 2 weeks on a small battery pack. Sap flow measurements on multiple corn stems were scaled up by population to estimate field-scale transpiration. During full canopy cover, excellent agreement was observed between the scaled-up sap flow measurements and reference crop evapotranspiration calculated from weather data. Data also showed promise as a way to estimate real-time canopy resistance required for model verification and development. Given the low-cost, low-power, and open-source characteristics of the system; the technology is well suited for applications requiring large number of gauges (spatial scaling or treatment comparisons). While early work was done with agricultural crops, the approach is well suited for other species such as riverine shrubs.

A comparison of commercial and custom-made electronic tracking systems to measure patient flow through an ambulatory clinic.

PubMed

Vakili, Sharif; Pandit, Ravi; Singman, Eric L; Appelbaum, Jeffrey; Boland, Michael V

2015-10-29

Understanding how patients move through outpatient clinics is important for optimizing clinic processes. This study compares the costs, benefits, and challenges of two clinically important methods for measuring patient flow: (1) a commercial system using infrared (IR) technology that passively tracks patient movements and (2) a custom-built, low cost, networked radio frequency identification (RFID) system that requires active swiping by patients at proximity card readers. Readers for both the IR and RFID systems were installed in the General Eye Service of the Wilmer Eye Institute. Participants were given both IR and RFID tags to measure the time they spent in various clinic stations. Simultaneously, investigators recorded the times at which patients moved between rooms. These measurements were considered the standard against which the other methods were compared. One hundred twelve patients generated a total of 252 events over the course of 6 days. The proportion of events successfully recorded by the RFID system (83.7%) was significantly greater than that obtained with the IR system (75.4%, p < 0.001). The cause of the missing events using the IR method was found to be a signal interruption between the patient tags and the check-in desk receiver. Excluding those data, the IR system successfully recorded 94.4% of events (p = 0.002; OR = 3.83 compared to the RFID system). There was no statistical difference between the IR, RFID, and manual time measurements (p > 0.05 for all comparisons). Both RFID and IR methods are effective at providing patient flow information. The custom-made RFID system was as accurate as IR and was installed at about 10% the cost. Given its significantly lower costs, the RFID option may be an appealing option for smaller clinics with more limited budgets.

Progress in fuel systems to meet new fuel economy and emissions standards

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

NONE

1995-12-31

This publication includes information describing the latest developments within the automotive industry on fuel system hardware and control strategies. Contents include: Slow heating process of a heated pintle-type gasoline fuel injector; Mixture preparation measurements; Study of fuel flow rate change in injector for methanol fueled S.I. engine; Flow and structural analysis for fuel pressure regulator performance; A new method to analyze fuel behavior in a spark ignition engine; Throttle body at engine idle -- tolerance effect on flow rate; and more.

An Analysis of Performance Measurements Systems in the Air Force Logistics Command’s Aircraft Repair Depots

DTIC Science & Technology

1992-01-01

aircraft it repairs, LA tracks negotiated flow versus actual flow by tail number and the number of days delivered early or late. This directorate, as...elements are defined as follows: Performance criterion: The relative element used to evaluate macro, micro, long -term, short-term, flow, static, functional...constraint is defined as "anything that limits the system from achieving higher performance versus its goal" (Goldratt, 1989, p. 1). The following

MRI-based noninvasive measurement of intracranial compliance derived from the relationship between transcranial blood and cerebrospinal fluid flows: modeling vs. direct approach

NASA Astrophysics Data System (ADS)

Tain, Rong-Wen; Alperin, Noam

2008-03-01

Intracranial compliance (ICC) determines the ability of the intracranial space to accommodate increase in volume (e.g., brain swelling) without a large increase in intracranial pressure (ICP). Therefore, measurement of ICC is potentially important for diagnosis and guiding treatment of related neurological problems. Modeling based approach uses an assumed lumped-parameter model of the craniospinal system (CSS) (e.g., RCL circuit), with either the arterial or the net transcranial blood flow (arterial inflow minus venous outflow) as input and the cranio-spinal cerebrospinal fluid (CSF) flow as output. The phase difference between the output and input is then often used as a measure of ICC However, it is not clear whether there is a predetermined relationship between ICC and the phase difference between these waveforms. A different approach for estimation of ICC has been recently proposed. This approach estimates ICC from the ratio of the intracranial volume and pressure changes that occur naturally with each heartbeat. The current study evaluates the sensitivity of the phase-based and the direct approach to changes in ICC. An RLC circuit model of the cranio-spinal system is used to simulate the cranio-spinal CSF flow for 3 different ICC states using the transcranial blood flows measured by MRI phase contrast from healthy human subjects. The effect of the increase in the ICC on the magnitude and phase response is calculated from the system's transfer function. We observed that within the heart rate frequency range, changes in ICC predominantly affected the amplitude of CSF pulsation and less so the phases. The compliance is then obtained for the different ICC states using the direct approach. The measures of compliance calculated using the direct approach demonstrated the highest sensitivity for changes in ICC. This work explains why phase shift based measure of ICC is less sensitive than amplitude based measures such as the direct approach method.

Flow networks for Ocean currents

NASA Astrophysics Data System (ADS)

Tupikina, Liubov; Molkenthin, Nora; Marwan, Norbert; Kurths, Jürgen

2014-05-01

Complex networks have been successfully applied to various systems such as society, technology, and recently climate. Links in a climate network are defined between two geographical locations if the correlation between the time series of some climate variable is higher than a threshold. Therefore, network links are considered to imply heat exchange. However, the relationship between the oceanic and atmospheric flows and the climate network's structure is still unclear. Recently, a theoretical approach verifying the correlation between ocean currents and surface air temperature networks has been introduced, where the Pearson correlation networks were constructed from advection-diffusion dynamics on an underlying flow. Since the continuous approach has its limitations, i.e., by its high computational complexity, we here introduce a new, discrete construction of flow-networks, which is then applied to static and dynamic velocity fields. Analyzing the flow-networks of prototypical flows we find that our approach can highlight the zones of high velocity by degree and transition zones by betweenness, while the combination of these network measures can uncover how the flow propagates within time. We also apply the method to time series data of the Equatorial Pacific Ocean Current and the Gulf Stream ocean current for the changing velocity fields, which could not been done before, and analyse the properties of the dynamical system. Flow-networks can be powerful tools to theoretically understand the step from system's dynamics to network's topology that can be analyzed using network measures and is used for shading light on different climatic phenomena.

Two-Photon Flow Cytometry

NASA Technical Reports Server (NTRS)

Zhog, Cheng Frank; Ye, Jing Yong; Norris, Theodore B.; Myc, Andrzej; Cao, Zhengyl; Bielinska, Anna; Thomas, Thommey; Baker, James R., Jr.

2004-01-01

Flow cytometry is a powerful technique for obtaining quantitative information from fluorescence in cells. Quantitation is achieved by assuring a high degree of uniformity in the optical excitation and detection, generally by using a highly controlled flow such as is obtained via hydrodynamic focusing. In this work, we demonstrate a two-beam, two- channel detection and two-photon excitation flow cytometry (T(sup 3)FC) system that enables multi-dye analysis to be performed very simply, with greatly relaxed requirements on the fluid flow. Two-photon excitation using a femtosecond near-infrared (NIR) laser has the advantages that it enables simultaneous excitation of multiple dyes and achieves very high signal-to-noise ratio through simplified filtering and fluorescence background reduction. By matching the excitation volume to the size of a cell, single-cell detection is ensured. Labeling of cells by targeted nanoparticles with multiple fluorophores enables normalization of the fluorescence signal and thus ratiometric measurements under nonuniform excitation. Quantitative size measurements can also be done even under conditions of nonuniform flow via a two-beam layout. This innovative detection scheme not only considerably simplifies the fluid flow system and the excitation and collection optics, it opens the way to quantitative cytometry in simple and compact microfluidics systems, or in vivo. Real-time detection of fluorescent microbeads in the vasculature of mouse ear demonstrates the ability to do flow cytometry in vivo. The conditions required to perform quantitative in vivo cytometry on labeled cells will be presented.

Flow chemistry vs. flow analysis.

PubMed

Trojanowicz, Marek

2016-01-01

The flow mode of conducting chemical syntheses facilitates chemical processes through the use of on-line analytical monitoring of occurring reactions, the application of solid-supported reagents to minimize downstream processing and computerized control systems to perform multi-step sequences. They are exactly the same attributes as those of flow analysis, which has solid place in modern analytical chemistry in several last decades. The following review paper, based on 131 references to original papers as well as pre-selected reviews, presents basic aspects, selected instrumental achievements and developmental directions of a rapidly growing field of continuous flow chemical synthesis. Interestingly, many of them might be potentially employed in the development of new methods in flow analysis too. In this paper, examples of application of flow analytical measurements for on-line monitoring of flow syntheses have been indicated and perspectives for a wider application of real-time analytical measurements have been discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Ducted fan inlet/exit and rotor tip flow improvements for vertical lift systems

NASA Astrophysics Data System (ADS)

Akturk, Ali

The current research utilized experimental and computational techniques in 5" and 22" diameter ducted fan test systems that have been custom designed and manufactured. Qualitative investigation of flow around the ducted fan was also performed using smoke flow visualizations. Quantitative measurements consisted of 2D and 3D velocity measurements using planar and Stereoscopic Particle Image Velocimetry (PIV and SPIV), high resolution total pressure measurements using Kiel total pressure probes and real time six-component force and torque measurements. The computational techniques used in this thesis included a recently developed radial equilibrium based rotor model(REBRM) and a three dimensional Reynolds-Averaged Navier Stokes (RANS) based CFD model. A radial equilibrium based rotor model (REBRM) developed by the author was effectively integrated into a three-dimensional RANS based computational system. The PIV measurements and computational flow predictions using (REBRM) near the fan inlet plane were in a good agreement at hover and forward flight conditions. The aerodynamic modifications resulting from the fan inlet flow distortions in forward flight regime were clearly captured in 2D PIV results. High resolution total pressure measurements at the downstream of the fan rotor showed that tip leakage, rotor hub separation, and passage flow related total pressure losses were dominant in hover condition. However, the losses were dramatically increased in forward flight because of inlet lip separation and distortion. A novel ducted fan inlet flow conditioning concept named "Double Ducted Fan" (DDF) was developed. The (DDF) concept has a potential to significantly improve the performance and controllability of VTOL UAVs and many other ducted fan based vertical lift systems. The new concept that will significantly reduce the inlet lip separation related performance penalties used a secondary stationary duct system to control "inlet lip separation" occurring especially at elevated forward flight velocities. The (DDF) is self-adjusting in a wide forward flight velocity range. DDFs corrective aerodynamic in influence becomes more pronounced with increasing flight velocity due to its inherent design properties. RANS simulations of the flow around rotor blades and duct geometry in the rotating frame of reference provided a comprehensive description of the tip leakage and passage flow in the flow environment of the two ducted fan research facilities developed throughout this thesis. The aerodynamic measurements and results of the RANS simulation showed good agreement especially near the tip region. A number of novel tip treatments based on custom designed pressure side extensions were introduced. Various tip leakage mitigation schemes were introduced by varying the chordwise location and the width of the extension in the circumferential direction. The current study showed that a proper selection of the pressure side bump location and width were the two critical parameters in influencing the success of the tip leakage mitigation approach. Significant gains in axial mean velocity component were observed when a proper pressure side tip extension was used. It is also observed that an effective tip leakage mitigation scheme significantly reduced the tangential velocity component near the tip of the axial fan blade. Reduced tip clearance related flow interactions were essential in improving the energy efficiency and range of ducted fan based vehicle. Full and inclined pressure side tip squealers were designed. Squealer tips were effective in changing the overall trajectory of the tip vortex to a higher path in radial direction. The interaction of rotor blades and tip vortex was effectively reduced and aerodynamic performance of the rotor blades was improved. The overall aerodynamic gain was a measurable reduction in leakage mass flow rate. This leakage reduction increased thrust significantly. Full and inclined pressure side tip squealers increased thrust obtained in hover condition by 9.1 % and 9.6 % respectively. A reduction or elimination of the momentum deficit in tip vortices is essential to reduce the adverse performance effects originating from the unsteady and highly turbulent tip leakage flows rotating against a stationary casing. The novel tip treatments developed throughout this thesis research are highly effective in reducing the adverse performance effects of ducted fan systems developed for VTOL vehicles. (Abstract shortened by UMI.)

Calibration, Data Acquisition, and Post Analysis of Turbulent Fluid Flow in a Calibration Jet Using Hot-wire Anemometry

NASA Technical Reports Server (NTRS)

Moreno, Michelle

2004-01-01

The Turbine Branch concentrates on the following areas: Computational Fluid Dynamics (CFD), and implementing experimental procedures to obtain physical modeling data. Hot-wire Anemometry is a valuable tool for obtaining physical modeling data. Hot-wire Anemometry is likely to remain the principal research tool for most turbulent air/gas flow studies. The Hot-wire anemometer consists of a fine wire heated by electric current. When placed in a fluid stream, the hot-wire loses heat to the fluid by forced convection. In forced convection, energy transfer is due to molecular motion imposed by an extraneous force moving fluid parcels. When the hot-wire is in "equilibrium", the rate of heat input to the wire is equal to the rate of heat loss at the wire ends. The equality between heat input and heat loss is the basis for King s equation, which relates the electrical parameters of the hot-wire to the flow parameters of the fluid. Hot-wire anemometry is based on convective heat transfer from a heated wire element placed in a fluid flow. Any change in the fluid flow condition that affects the heat transfer from the heated element will be detected virtually instantaneously by a constant-temperature Hot-wire anemometry system. The system implemented for this research is the IFA 300. The system is a fully-integrated, thermal anemometer-based system that measures mean and fluctuating velocity components in air, water, and other fluids. It also measures turbulence and makes localized temperature measurements. A constant-temperature anemometer is a bridge and amplifier circuit that controls a tiny wire at constant temperature. As a fluid flow passes over the heated sensor, the amplifier senses the bridge off-balance and adjusts the voltage to the top of the bridge, keeping the bridge in balance. The voltage on top of the bridge can then be related to the velocity of the flow. The bridge voltage is sensitive to temperature as well as velocity and so the built-in thermocouple circuit can be attached to a thermocouple that can measure the fluid temperature. Additional information is included in the original extended abstract.

Mock Circulatory System of the Fontan Circulation to Study Respiration Effects on Venous Flow Behavior

PubMed Central

Vukicevic, M.; Chiulli, J.A.; Conover, T.; Pennati, G.; Hsia, T.Y.; Figliola, R.S.

2013-01-01

We describe an in vitro model of the Fontan circulation with respiration to study subdiaphragmatic venous flow behavior. The venous and arterial connections of a total cavopulmonary connection (TCPC) test section were coupled with a physical lumped parameter (LP) model of the circulation. Intrathoracic and subdiaphragmatic pressure changes associated with normal breathing were applied. This system was tuned for two patients (5 years, 0.67 m2; 10 years, 1.2 m2) to physiological values. System function was verified by comparison to the analytical model on which it was based and by consistency with published clinical measurements. Overall, subdiaphragmatic venous flow was influenced by respiration. Flow within the arteries and veins increased during inspiration but decreased during expiration with retrograde flow in the inferior venous territories. System pressures and flows showed close agreement with the analytical LP model (p < 0.05). The ratio of the flow rates occurring during inspiration to expiration were within the clinical range of values reported elsewhere. The approach used to setup and control the model was effective and provided reasonable comparisons with clinical data. PMID:23644612

Numerical and experimental analysis of a thin liquid film on a rotating disk related to development of a spacecraft absorption cooling system

NASA Technical Reports Server (NTRS)

Faghri, Amir; Swanson, Theodore D.

1989-01-01

The numerical and experimental analysis of a thin liquid film on a rotating and a stationary disk related to the development of an absorber unit for a high capacity spacecraft absorption cooling system, is described. The creation of artificial gravity by the use of a centrifugal field was focused upon in this report. Areas covered include: (1) One-dimensional computation of thin liquid film flows; (2) Experimental measurement of film height and visualization of flow; (3) Two-dimensional computation of the free surface flow of a thin liquid film using a pressure optimization method; (4) Computation of heat transfer in two-dimensional thin film flow; (5) Development of a new computational methodology for the free surface flows using a permeable wall; (6) Analysis of fluid flow and heat transfer in a thin film in the presence and absence of gravity; and (7) Comparison of theoretical prediction and experimental data. The basic phenomena related to fluid flow and heat transfer on rotating systems reported here can also be applied to other areas of space systems.

Probe Without Moving Parts Measures Flow Angle

NASA Technical Reports Server (NTRS)

Corda, Stephen; Vachon, M. Jake

2003-01-01

The measurement of local flow angle is critical in many fluid-dynamic applications, including the aerodynamic flight testing of new aircraft and flight systems. Flight researchers at NASA Dryden Flight Research Center have recently developed, flight-tested, and patented the force-based flow-angle probe (FLAP), a novel, force-based instrument for the measurement of local flow direction. Containing no moving parts, the FLAP may provide greater simplicity, improved accuracy, and increased measurement access, relative to conventional moving vane-type flow-angle probes. Forces in the FLAP can be measured by various techniques, including those that involve conventional strain gauges (based on electrical resistance) and those that involve more advanced strain gauges (based on optical fibers). A correlation is used to convert force-measurement data to the local flow angle. The use of fiber optics will enable the construction of a miniature FLAP, leading to the possibility of flow measurement in very small or confined regions. This may also enable the tufting of a surface with miniature FLAPs, capable of quantitative flow-angle measurements, similar to attaching yarn tufts for qualitative measurements. The prototype FLAP was a small, aerodynamically shaped, low-aspect-ratio fin about 2 in. (approximately equal to 5 cm) long, 1 in. (approximately equal to 2.5 cm) wide, and 0.125 in. (approximately equal to 0.3 cm) thick (see Figure 1). The prototype FLAP included simple electrical-resistance strain gauges for measuring forces. Four strain gauges were mounted on the FLAP; two on the upper surface and two on the lower surface. The gauges were connected to form a full Wheatstone bridge, configured as a bending bridge. In preparation for a flight test, the prototype FLAP was mounted on the airdata boom of a flight-test fixture (FTF) on the NASA Dryden F-15B flight research airplane.

Optically based quantification of absolute cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution in rodents

NASA Astrophysics Data System (ADS)

Yaseen, Mohammad A.; Srinivasan, Vivek J.; Sakadžić, Sava; Vinogradov, Sergei A.; Boas, David A.

2010-02-01

Measuring oxygen delivery in brain tissue is important for identifying the pathophysiological changes associated with brain injury and various diseases such as cancer, stroke, and Alzheimer's disease. We have developed a multi-modal imaging system for minimally invasive measurement of cerebral oxygenation and blood flow in small animals with high spatial resolution. The system allows for simultaneous measurement of blood flow using Fourier-domain optical coherence tomography, and oxygen partial pressure (pO2) using either confocal or multiphoton phosphorescence lifetime imaging with exogenous porphyrin-based dyes sensitive to dissolved oxygen. Here we present the changes in pO2 and blood flow in superficial cortical vessels of Sprague Dawley rats in response to conditions such as hypoxia, hyperoxia, and functional stimulation. pO2 measurements display considerable heterogeneity over distances that cannot be resolved with more widely used oxygen-monitoring techniques such as BOLD-fMRI. Large increases in blood flow are observed in response to functional stimulation and hypoxia. Our system allows for quantification of cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution, providing a better understanding of metabolic dynamics during functional stimulation and under various neuropathologies. Ultimately, better insight into the underlying mechanisms of neuropathologies will facilitate the development of improved therapeutic strategies to minimize damage to brain tissue.

The relationship between BNP, NTproBNP and echocardiographic measurements of systemic blood flow in very preterm infants.

PubMed

König, K; Guy, K J; Walsh, G; Drew, S M; Watkins, A; Barfield, C P

2014-04-01

Preterm infants are at risk of circulatory compromise following birth. Functional neonatal echocardiography including superior vena cava (SVC) flow is increasingly used in neonatal medicine, and low SVC flow has been associated with adverse outcome. However, echocardiography is not readily available in many neonatal units and B-type natriuretic peptides (BNPs) may be useful in guiding further cardiovascular assessment. This study investigated the relationship between BNP, N-terminal pro-BNP (NTproBNP) and echocardiographic measurements of systemic blood flow in very preterm infants. This is a prospective observational study. Sixty preterm infants <32 weeks gestational age were included after the treating neonatologist had requested an echocardiogram for suspected cardiovascular compromise. BNP and NTproBNP were sampled just before the echocardiogram. Echocardiographic examination included fractional shortening (FS), SVC flow, left and right ventricular output (LVO and RVO). Statistical analysis included simple linear regression of BNP and NTproBNP with echocardiographic measures and multiple regression including potential confounding variables. Mean (s.d.) gestational age at birth was 27(5) (2(1)) weeks, median (interquartile range, IQR) birth weight was 995 (845 to 1175) grams. Neither BNP nor NTproBNP correlated with SVC flow (BNP 95% confidence interval (CI) -0.0014 to 0.013, P=0.12; NTproBNP 95% CI -0.00069 to 0.01, P=0.085); LVO (BNP 95% CI -0.00078 to 0.0072, P=0.11; NTproBNP 95% CI -0.0034 to 0.0034, P=0.99); RVO (BNP 95% CI -0.00066 to 0.0058, P=0.12; NTproBNP 95% CI -0.0012 to 0.0044, P=0.25); or FS (BNP 95% CI -0.053 to 0.051, P=0.96; NTproBNP 95% CI -0.061 to 0.019, P=0.3). Multivariate linear regression did not significantly alter results. In this cohort of very preterm infants, BNP and NTproBNP did not correlate with echocardiographic measurements of systemic blood flow within the first 72 h of life.

40 CFR 60.73a - Emissions testing and monitoring.

Code of Federal Regulations, 2013 CFR

2013-07-01

... system (e.g., weigh scale, volume flow meter, mass flow meter, tank volume) to measure and record the... via titration or by determining the temperature and specific gravity of the nitric acid. You may also...

40 CFR 60.73a - Emissions testing and monitoring.

Code of Federal Regulations, 2014 CFR

2014-07-01

... system (e.g., weigh scale, volume flow meter, mass flow meter, tank volume) to measure and record the... via titration or by determining the temperature and specific gravity of the nitric acid. You may also...

Development of a Compact, Deep-Penetrating Heat Flow Instrument for Lunar Landers: In-Situ Thermal Conductivity System

NASA Technical Reports Server (NTRS)

Nagihara, S.; Zacny, K.; Hedlund, M.; Taylor, P. T.

2012-01-01

Geothermal heat flow is obtained as a product of the geothermal gradient and the thermal conductivity of the vertical soil/rock/regolith interval penetrated by the instrument. Heat flow measurements are a high priority for the geophysical network missions to the Moon recommended by the latest Decadal Survey and previously the International Lunar Network. One of the difficulties associated with lunar heat flow measurement on a robotic mission is that it requires excavation of a relatively deep (approx 3 m) hole in order to avoid the long-term temporal changes in lunar surface thermal environment affecting the subsurface temperature measurements. Such changes may be due to the 18.6-year-cylcle lunar precession, or may be initiated by presence of the lander itself. Therefore, a key science requirement for heat flow instruments for future lunar missions is to penetrate 3 m into the regolith and to measure both thermal gradient and thermal conductivity. Engineering requirements are that the instrument itself has minimal impact on the subsurface thermal regime and that it must be a low-mass and low-power system like any other science instrumentation on planetary landers. It would be very difficult to meet the engineering requirements, if the instrument utilizes a long (> 3 m) probe driven into the ground by a rotary or percussive drill. Here we report progress in our efforts to develop a new, compact lunar heat flow instrumentation that meets all of these science and engineering requirements.

Method and device for determining heats of combustion of gaseous hydrocarbons

NASA Technical Reports Server (NTRS)

Singh, Jag J. (Inventor); Sprinkle, Danny R. (Inventor); Puster, Richard L. (Inventor)

1988-01-01

A method and device is provided for a quick, accurate and on-line determination of heats of combustion of gaseous hydrocarbons. First, the amount of oxygen in the carrier air stream is sensed by an oxygen sensing system. Second, three individual volumetric flow rates of oxygen, carrier stream air, and hydrocrabon test gas are introduced into a burner. The hydrocarbon test gas is fed into the burner at a volumetric flow rate, n, measured by a flowmeter. Third, the amount of oxygen in the resulting combustion products is sensed by an oxygen sensing system. Fourth, the volumetric flow rate of oxygen is adjusted until the amount of oxygen in the combustion product equals the amount of oxygen previously sensed in the carrier air stream. This equalizing volumetric flow rate is m and is measured by a flowmeter. The heat of combustion of the hydrocrabon test gas is then determined from the ratio m/n.

Numerical simulation of flow in deep open boreholes in a coastal freshwater lens, Pearl Harbor Aquifer, O‘ahu, Hawai‘i

USGS Publications Warehouse

Rotzoll, Kolja

2012-01-01

The Pearl Harbor aquifer in southern O‘ahu is one of the most important sources of freshwater in Hawai‘i. A thick freshwater lens overlays brackish and saltwater in this coastal aquifer. Salinity profiles collected from uncased deep monitor wells (DMWs) commonly are used to monitor freshwater-lens thickness. However, vertical flow in DMWs can cause the measured salinity to differ from salinity in the adjacent aquifer or in an aquifer without a DWM. Substantial borehole flow and displacement of salinity in DMWs over several hundred feet have been observed in the Pearl Harbor aquifer. The objective of this study was to evaluate the effects of borehole flow on measured salinity profiles from DMWs. A numerical modeling approach incorporated aquifer hydraulic characteristics and recharge and withdrawal rates representative of the Pearl Harbor aquifer. Borehole flow caused by vertical hydraulic gradients associated with both the natural regional flow system and groundwater withdrawals was simulated. Model results indicate that, with all other factors being equal, greater withdrawal rates, closer withdrawal locations, or higher hydraulic conductivities of the well cause greater borehole flow and displacement of salinity in the well. Borehole flow caused by the natural groundwater-flow system is five orders of magnitude greater than vertical flow in a homogeneous aquifer, and borehole-flow directions are consistent with the regional flow system: downward flow in inland recharge areas and upward flow in coastal discharge areas. Displacement of salinity inside the DMWs associated with the regional groundwater-flow system ranges from less than 1 to 220 ft, depending on the location and assumed hydraulic conductivity of the well. For example, upward displacements of the 2 percent and 50 percent salinity depths in a well in the coastal discharge part of the flow system are 17 and 4.4 ft, respectively, and the average salinity difference between aquifer and borehole is 0.65 percent seawater salinity. Groundwater withdrawals and drawdowns generally occur at shallow depths in the freshwater system with respect to the depth of the DMW and cause upward flow in the DMW. Simulated groundwater withdrawal of 4.3 million gallons per day that is 100 ft from a DMW causes thirty times more borehole flow than borehole flow that is induced by the regional flow field alone. The displacement of the 2 percent borehole salinity depth increases from 17 to 33 ft, and the average salinity difference between aquifer and borehole is 0.85 percent seawater salinity. Peak borehole flow caused by local groundwater withdrawal near DMWs is directly proportional to the pumping rate in the nearby production well. Increasing groundwater withdrawal to 16.7 million gallons per day increases upward displacement of the 50 percent salinity depth (midpoint of the transition zone) from 4.6 to 77 ft, and the average salinity difference between aquifer and borehole is 1.4 percent seawater salinity. Simulated groundwater withdrawal that is 3,000 ft away from DMWs causes less borehole flow and salinity displacements than nearby withdrawal. Simulated effects of groundwater withdrawal from a horizontal shaft and withdrawal from a vertical well in a homogeneous aquifer were similar. Generally, the 50 percent salinity depths are less affected by borehole flow than the 2 percent salinity depths. Hence, measured salinity profiles are useful for calibration of regional numerical models despite borehole-flow effects. Commonly, a 1 percent error in salinity is acceptable in numerical modeling studies. Incorporation of heterogeneity in the model is necessary to simulate long vertical steps observed in salinity profiles in southern O‘ahu. A thick zone of low aquifer hydraulic conductivity limits exchange of water between aquifer and well and creates a long vertical step in the salinity profile. A heterogeneous basalt-aquifer scenario simulates observed vertical salinity steps and borehole flow that is consistent with measured borehole flow from DMWs in southern O‘ahu. However, inclusion of local-scale heterogeneities in regional models generally is not warranted.

Determination of YAV-8B Reaction Control System bleed flow usage

NASA Technical Reports Server (NTRS)

Borchers, Paul F.; Moralez, Ernesto, III; Merrick, Vernon K.; Stortz, Michael W.; Eames, David J. H.

1992-01-01

Using a calibrated Rolls-Royce Pegasus engine, total Reaction Control System (RCS) bleed flow rates have been measured on a YAV-8B Harrier during typical short takeoff, transition, hover and vertical landing maneuvers. Using existing aircraft instrumentation and pressure taps located in the RCS ducts, bleed flow rates at each RCS valve were also measured directly during flight and ground tests. These data were compared with the calibrated engine data and with the RCS part of a YAV-8B mathematical model used in piloted simulation at NASA Ames Research Center. Areas of disagreement were small, being confined to the estimation of closed RCS valve leakages and the modeling of the RCS butterfly valve pressure losses.

Hydrogeology, groundwater levels, and generalized potentiometric-surface map of the Green River Basin lower Tertiary aquifer system, 2010–14, in the northern Green River structural basin

USGS Publications Warehouse

Bartos, Timothy T.; Hallberg, Laura L.; Eddy-Miller, Cheryl

2015-07-14

The groundwater-level measurements were used to construct a generalized potentiometric-surface map of the Green River Basin lower Tertiary aquifer system. Groundwater-level altitudes measured in nonflowing and flowing wells used to construct the potentiometric-surface map ranged from 6,451 to 7,307 feet (excluding four unmeasured flowing wells used for contour construction purposes). The potentiometric-surface map indicates that groundwater in the study area generally moves from north to south, but this pattern of flow is altered locally by groundwater divides, groundwater discharge to the Green River, and possibly to a tributary river (Big Sandy River) and two reservoirs (Fontenelle and Big Sandy Reservoirs).

Evaluation of Flow Biosensor Technology in a Chronically-Instrumented Non-Human Primate Model

NASA Technical Reports Server (NTRS)

Koenig, S. C.; Reister, C.; Schaub, J.; Muniz, G.; Ferguson, T.; Fanton, J. W.

1995-01-01

The Physiology Research Branch of Brooks AFB conducts both human and non-human primate experiments to determine the effects of microgravity and hypergravity on the cardiovascular system and to indentify the particular mechanisms that invoke these responses. Primary investigative research efforts in a non-human primate model require the calculation of total peripheral resistance (TPR), systemic arterial compliance (SAC), and pressure-volume loop characteristics. These calculations require beat-to-beat measurement of aortic flow. We have evaluated commercially available electromagnetic (EMF) and transit-time flow measurement techniques. In vivo and in vitro experiments demonstrated that the average error of these techniques is less than 25 percent for EMF and less than 10 percent for transit-time.