Showing papers on "Pressure measurement published in 2003"

Properties of diamond under hydrostatic pressures up to 140 GPa.

Abstract: Diamond is the archetypal covalent material. Each atom in an sp3 configuration is bonded to four nearest neighbours. Because of its remarkable properties, diamond has been extensively studied1. And yet our knowledge of the properties of diamond under very high pressure is still incomplete. Although diamond is known to be the preferred allotrope of carbon at high pressure, the possibility of producing under pressure high-density polymorphs of diamond, including metallic forms, has been discussed2,3,4. Structural changes have already been reported in diamond under non-hydrostatic pressures around 150 GPa and large deformation5. However, measurements6,7,8 of the properties of diamond under hydrostatic pressure have been limited to below 40 GPa. Here, we report accurate measurements of the volume and of the optical phonon frequency of diamond under hydrostatic pressure up to 140 GPa. We show that diamond is more compressible than currently expected. By combining the volume and the frequency pressure shifts, we deduce that diamond remains very stable under pressure: it is a Gruneisen solid up to at least 140 GPa, and the covalent bond is even slightly strengthened under pressure. Finally, the optical phonon frequency versus pressure is calibrated here to be used as a pressure gauge for diamond anvil cell studies in the multi-megabar range.

Active Flow Separation Control of a Stator Vane Using Embedded Injection in a Multistage Compressor Experiment

Abstract: Micro-flow control actuation embedded in a stator vane was used to successfully control separation and improve near stall performance in a multistage compressor rig at NASA Glenn. Using specially designed stator vanes configured with internal actuation to deliver pulsating air through slots along the suction surface, a research study was performed to identify performance benefits using this microflow control approach. Pressure profiles and unsteady pressure measurements along the blade surface and at the shroud provided a dynamic look at the compressor during microflow air injection. These pressure measurements lead to a tracking algorithm to identify the onset of separation. The testing included steady air injection at various slot locations along the vane. The research also examined the benefit of pulsed injection and actively controlled air injection along the stator vane. Two types of actuation schemes were studied, including an embedded actuator for on-blade control. Successful application of an online detection and flow control scheme will be discussed. Testing showed dramatic performance benefit for flow reattachment and subsequent improvement in diffusion through the use of pulsed controlled injection. The paper will discuss the experimental setup, the blade configurations, and preliminary CFD results which guided the slot location along the blade. The paper will also show the pressure profiles and unsteady pressure measurements used to track flow control enhancement, and will conclude with the tracking algorithm for adjusting the control.

Micro-mechanical capacitive inductive sensor for wireless detection of relative or absolute pressure

Abstract: A micro-mechanical pressure transducer is disclosed in which a capacitive transducer structure is integrated with an inductor coil to form a LC tank circuit, resonance frequency of which may be detected remotely by imposing an electromagnetic field on the transducer. The capacitive transducer structure comprises a conductive movable diaphragm, a fixed counter electrode, and a predetermined air gap between said diaphragm and electrode. The diaphragm deflects in response to an applied pressure differential, leading to a change of capacitance in the structure and hence a shift of resonance frequency of the LC tank circuit. The resonance frequency of the LC circuit can be remotely detected by measuring and determining the corresponding peak in electromagnetic impedance of the transducer.

Estimation of central aortic pressure by SphygmoCor requires intra-arterial peripheral pressures.

Abstract: Central arterial pressure, measured close to the heart, may be of more patho-physiological importance than conventional non-invasive cuff blood pressure. The technique of applanation tonometry using SphygmoCor® has been proposed as a non-invasive method of estimating central pressure. This relies on mathematically derived generalized transfer functions, which have been previously validated using invasive peripheral pressure measurements. We compared simultaneous estimates of central aortic pressure using this technique with those measured directly during the routine diagnostic cardiac catheterization of 30 subjects (age range 27–84 years), half of whom were aged 65 years or more. This was done by applanating the left radial artery and recording the non-invasive brachial cuff blood pressure to generate a central aortic pressure estimate, using the SphygmoCor® radial transfer function. The comparative results were analysed using Bland—Altman plots of mean difference. SphygmoCor®, on average, underestimated systolic central arterial pressure by 13.3 mmHg and overestimated diastolic pressure by 11.5 mmHg. The results were similar in patients aged under and above 65 years. Furthermore, non-invasively measured brachial pressures were seen to give an overall closer estimate of the central arterial pressure than the SphygmoCor® system. The transfer function has been validated from invasively measured arterial pressures and the current use by the system of non-invasive measures may explain the discrepancies. However, age, drugs and arterial disease would also be expected to play a role.

Endotracheal tube pressure monitoring system and method of controlling same

Abstract: An endotracheal tube pressure monitoring system for an endotracheal tube having at least pressure sensor in communication with a major lumen of the endotracheal tube, and a pressure monitoring subsystem in operative communication with the pressure sensor. The system may also have at least one fluid pressure line in fluid communication with the major lumen and in operative communication with the pressure monitoring subsystem to monitor the pressure of fluid within each respective fluid pressure line, and a purging subsystem in fluid communication with the fluid pressure line. Each fluid pressure line that is in fluid communication with the purging subsystem being selectively purged by the purging subsystem when pressure monitoring subsystem determines the respective pressure line has become obstructed. Purging the fluid pressure line maintains the patency of the pressure line so that accurate pressure measurements within the endotracheal tube can be obtained for calculation of parameters in lung mechanics. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 C.F.R. §1.72(b).

Embedded micromachined fiber-optic Fabry-Perot pressure sensors in aerodynamics applications

Abstract: Small size, high bandwidth pressure sensors are required for instrumentation of probes and test models in aerodynamic studies of complex unsteady flows. Optical-fiber pressure sensors promise potential advantages of small size and low cost in comparison with their electrical counterparts. We describe miniature Fabry-Perot cavity pressure sensors constructed by micromachining techniques in a turbine test application. The sensor bodies are 500 /spl mu/m squared, 300 /spl mu/m deep with a /spl sim/2 /spl mu/m-thick copper diaphragm electroplated on one face. The sensor cavity is formed between the diaphragm and the cleaved end of a single mode fiber sealed to the sensor by epoxy. Each sensor is addressed interferometrically in reflection by three wavelengths simultaneously, giving an unambiguous phase determination; a pressure sensitivity of 1.6 radbar/sup -1/ was measured, with a typical range of vacuum to 600 kPa. Five sensors were embedded in the trailing edge of a nozzle guide vane installed upstream of a rotor in a full-scale turbine stage transient test facility. Pressure signals in the trailing edge flow show marked structure at the 8 kHz blade passing frequency. To our knowledge, this is the first report of sensors located at the trailing edge of a normal-sized turbine blade.

Process measurement and analysis

Abstract: GENERAL CONSIDERATIONS Flowsheet Symbols and P&I Diagrams Functional Diagrams and Function Symbols Instrument Terminology and Performance System Accuracy Uncertainty Calculations Configuring Intelligent Devices Instrument Installation Instrument Calibration Response Time and Drift Testing Redundant and Voting Systems Instrument Evaluation Binary Logic Diagrams FLOW MEASUREMENT Application and Selection Anemometers BTU Flowmeters for Heat Exchangers BTU Flowmeters for Gaseous Fuels Cross-Correlation Flow Metering Elbow Taps Flow Switches Jet Deflection Flow Detectors Laminar Flowmeters Magnetic Flowmeters Mass Flowmeters, Coriolis Mass Flowmeters-Miscellaneous Mass Flowmeters-Thermal Metering Pumps Orifices Pitot Tubes and Area Averaging Units Polyphase (Oil/Water/Gas) Flowmeters Positive-Displacement Gas Flowmeters Positive-Displacement Liquid Meters and Provers Purge Flow Regulators Segmental Wedge Flowmeter Sight Flow Indicators Solids Flowmeters and Feeders Target Meters Turbine and Other Rotary Element Flowmeters Ultrasonic Flowmeters Variable-Area, Gap, and Vane Flowmeters V-Cone Flowmeter Venturi Tubes, Flow Tubes, and Flow Nozzles Vortex and Fluidic Flowmeters Weirs and Flumes LEVEL MEASUREMENT Application and Selection Bubblers Capacitance and Radio Frequency (RF) Admittance Probes Conductivity and Field Effect Level Switches Diaphragm Level Detectors Differential Pressure Level Detectors Displacer Level Detectors Float Level Devices Laser Level Sensors Level Gauges, Including Magnetic Microwave Level Switches Optical Level Devices Radar, Noncontacting Level Sensors Radar, Contact Level Sensors (TDR, GWR, PDS) Radiation Level Sensors Resistance Tapes Rotating Paddle Switches Tank Gauges Including Float-Type Tape Gauges Thermal Level Sensors Time Domain Reflectometry and Phase Difference Sensors Ultrasonic Level Detectors Vibrating Level Switches TEMPERATURE MEASUREMENT Application and Selection Bimetallic Thermometers Calibrators and Simulators Color Indicators, Crayons, Pellets Fiber-Optic Thermometers Filled-Bulb and Glass-Stem Thermometers Integrated Circuitry (IC) Transistors and Diodes Miscellaneous Temperature Sensors Pneumatic and Suction Pyrometers Pyrometric Cones Radiation and Infrared Pyrometers Quartz Crystal Thermometry Resistance Temperature Detectors (RTDs) Temperature Switches and Thermostats Thermistors Thermocouples Thermowells Ultrasonic Thermometers PRESSURE MEASUREMENT Selection and Application Accessories: Seals, Snubbers, Calibrators, and Manifolds Bellows-Type Pressure Sensors Bourdon and Helical Pressure Sensors Diaphragm or Capsule-Type Sensors Differential Pressure Instruments Electronic Pressure Sensors High-Pressure Sensors Manometers Multiple Pressure Scanners Multiple Pressure Scanners Pressure Gauges Pressure Repeaters Pressure and Differential Pressure Switches Vacuum Sensors DENSITY MEASUREMENT Density: Applications and Selection Displacement- and Float-Type Densitometers Hydrometers Hydrostatic Densitometers Oscillating Coriolis Densitometer (Gas, Liquid, and Slurry Services) Radiation Densitometers Ultrasonic Sludge and Slurry Densitometers Liquid/Slurry/Gas Density-Vibrating Densitometers Weight-Based and Miscellaneous Densitometers Gas Densitometers SAFETY AND MISCELLANEOUS SENSORS Boroscopes Electrical and Intrinsic Safety Electrical Meters and Sensors Energy Management Devices (Peak Load Shedding) Excess Flow and Regular Check Valves Explosion Suppression and Deluge Systems Flame Arresters, Conservation Vents, and Emergency Vents Flame, Fire, and Smoke Detectors Leak Detectors Linear and Angular Position Detection Machine Vision Technology Metal Detectors Noise Sensors Proximity Sensors and Limit Switches Relief Valves-Determination of Required Capacity Relief Valves-Sizing, Specification, and Installation Rupture Discs Soft Sensors Tachometers and Angular Speed Detectors Thickness and Dimension Measurement Torque and Force Transducers Vibration, Shock, and Acceleration Weather Stations Weighing Systems: General Considerations Weight Sensors ANALYTICAL INSTRUMENTATION Analyzer Application and Selection Analyzer Sampling: Process Samples Analyzer Sampling: Stack Particulates Analyzers Operating on Electrochemical Principles Air Quality Monitoring Biometers Biochemical Oxygen Demand, Chemical Oxygen Demand, and Total Oxygen Demand Calorimeters Carbon Dioxide Carbon Monoxide Chlorine Chromatographs: Gas Chromatographs: Liquid Coal Analyzers Colorimeters Combustibles Conductivity Analyzers Consistency Analyzers Corrosion Monitoring Differential Vapor Pressure Sensor Dioxin Analysis Elemental Monitors Fiber-Optic Probes Fluoride Analyzers Hydrocarbon Analyzers Hydrogen Sulfide Infrared Analyzers Ion-Selective Electrodes Mass Spectrometers Mercury in Air Mercury in Water Moisture in Air: Humidity and Dew Point Moisture in Gases and Liquids Moisture in Solids Molecular Weight Nitrate, Ammonia, and Total Nitrogen Nitrogen Oxide Analyzers Odor Detection Oil in or on Water Open Path Spectrometry Oxidation-Reduction Potential (ORP) Oxygen in Gases Oxygen in Liquids (Dissolved Oxygen) Ozone in Gas Ozone in Water Particulates, Opacity, Dust, and Smoke Particle Size and Distribution Monitors pH Measurement Phosphorus Analyzer Physical Properties Analyzers - ASTM Methods Raman Analyzers Refractometers Rheometers Streaming Current or Particle Charge Analyzer Sulfur-in-Oil Analyzers Sulfur Oxide Analyzers Thermal Conductivity Detectors Total Carbon Analyzers Toxic Gas Monitoring Turbidity, Sludge, and Suspended Solids Ultraviolet and Visible Analyzers Viscometers-Application and Selection Viscometers-Laboratory Viscometers-Industrial Water Quality Monitoring Wet Chemistry and Autotitrator Analyzers APPENDIX International System of Units Engineering Conversion Factors Chemical Resistance of Materials Composition of Metallic and Other Materials Steam and Water Tables Friction Loss in Pipes Tank Volumes Directory of "Lost" Companies INDEX

Megabar high‐pressure cells for Raman measurements

Abstract: Experimental aspects of Raman measurements at megabar pressures are considered. Features of diamond anvil cells working above 200 GPa are described. Problems of luminescence background at megabar pressures and the use of low-luminescence diamonds are considered. Methods of pressure measurements at very high pressures are discussed. The pressure dependence of the Raman shift from the diamond anvil tip was used as a reliable estimate of the pressure. Copyright © 2003 John Wiley & Sons, Ltd.

Pressure mapping systems: reliability of pressure map interpretation

Abstract: Background: Pressure mapping systems offer a new technology to assist with pressure care assessment. Data output from such systems can be presented in three forms: numerical data, a three-dimensional grid and a colour-coded pressure map.Objectives: To (1) investigate whether sole use of the pressure map was a reliable method of interpreting interface pressures when compared with use of the numerical data; (2) establish the inter and intra-rater reliability of using pressure maps to assess pressure and determine whether reliability depended upon system operator experience; and (3) examine whether reliability extended to the range of seating surfaces being tested.Design: A reliability study assessing the ranking of pressure maps recorded by the Force Sensing Array pressure mapping system.Setting: A university occupational therapy department and a community NHS trust.Subjects: Fifteen occupational therapists with experience in pressure mapping and 50 occupational therapy students with no practical experience...

A doubly anchored surface micromachined Pirani gauge for vacuum package characterization

Abstract: This paper presents a surface micromachined Pirani gauge for measuring vacuum pressure inside sealed micro cavities. This thin gap (800nm) SiO/sub 2//Si/sub 3/N/sub 4//SiO/sub 2/ gauge can measure absolute pressure from atmospheric to less than 1mTorr without sophisticated interface electronics by using a reliable software calibration technique. This allows the sensor to be integrated with common vacuum packaging technologies to measure leak rates as low as 10/sup -17/cm/sup 3//s. This represents a 5 order of magnitude improvement over traditional helium leak testing with a substantially reduced cost.

Distributed feedback fiber laser sensor for hydrostatic pressure

Abstract: We investigate a distributed feedback fiber laser sensor for fluid pressure up to 50 MPa and temperatures up to 250/spl deg/C. The protection of the fiber and the effects of the fiber coating on the sensor response are also analyzed.

Pore pressure estimation in reservoir rocks from seismic reflection data

Abstract: A method is used to obtain pore pressure in shaly sandstones based upon an acoustic model for seismic velocity versus clay content and effective pressure. Calibration of the model requires log data—porosity, clay content, and sonic velocities—to obtain the dry-rock moduli and the effective stress coefficients as a function of depth and pore pressure. The seismic P-wave velocity, derived from reflection tomography, is fitted to the theoretical velocity by using pore pressure as the fitting parameter. This approach, based on a rock-physics model, is an improvement over existing pore-pressure prediction methods, which mainly rely on empirical relations between velocity and pressure. The method is applied to the Tune field in the Viking Graben sedimentary basin of the North Sea. We have obtained a high-resolution velocity map that reveals the sensitivity to pore pressure and fluid saturation in the Tarbert reservoir. The velocity map of the Tarbert reservoir and the inverted pressure distribution agree with the structural features of the Tarbert Formation and its known pressure compartments.

Improved interpretation of wireline pressure data

Abstract: Modern wireline pressure data can have resolution and reproducibility sufficient to detect small fluid-density changes and pressure barriers, yet these features are commonly overlooked on conventional pressure-depth plots. The large pressure variation caused by weight of subsurface fluids hides these subtle features. Excess pressure is the pressure left after subtracting the weight of a fluid from the total pressure. This concept is applied to wireline pressure data to remove effects of weight and emphasize subtle pressure differences caused by density variations and pressure barriers. Fluid-density changes of 0.02 g/cm3 or less can be resolved, and within-well pressure barriers in the order of 5 kPa (0.7 psi) can be detected. Using good-quality data, effects of reservoir capillary-displacement pressure can be detected by offset of the free-water level from the petroleum-water contact. This effect can be used to estimate reservoir wettability. Subsurface fluid-density measurements can also be used to evaluate oil or gas quality on a bed-by-bed scale in traps having variable oil or gas composition, to detect compartmentalization by small petroleum density differences, to verify quality of samples for PVT (pressure, volume, temperature) analysis, and estimate salinity or temperature of unsampled water zones.Data quality limits barrier and fluid-contact resolution; thus, quality control is essential. Pressure measurement errors on the 3-kPa (0.5-psi) scale can be detected from behavior of the buildup pressure. Tests having the potential for small amounts of supercharge are identified from the overbalance and formation mobility. Examples illustrate identification of free-water levels and fluid contacts, fluid identification, supercharge identification, and water-zone compartmentalization.

A novel high temperature pressure sensor on the basis of SOI layers

Abstract: The principle of silicon-on-insulator (SOI) and low pressure chemical vapour deposited (LPCVD) to make the piezoresisitive pressure gauge is developed. A novel structure of the sensors for harsh environment is designed. In particular, the high temperature pressure sensors were used in: automotive industry, aviation engineering, as well as in oil fields, industrial measurement and control systems. The sensor could be used in 200 °C environment, and could endure the impact of instances high temperature (about 1000, and less than 0.5 s) because of it’s mechanical structure of cantilever bonded with SOI strain gauge. The test data of the sensor is obtained, and the result is satisfied.

Method for analysis of single pulse pressure waves

Abstract: This invention relates to a method for analysing pressure-signals derivable from pressure measurements on or in a body of a human being or animal, comprising the steps of identifying during given time sequences in a series of time sequences the single pressure waves, including related parameters [pressure amplitude ΔP, latency (ΔT), rise time coefficient (ΔP/ΔT)], determining numbers of single pressure waves with pre-selected combinations of two or more of said single pressure wave parameters during said time sequence. For the time sequences is further determined the balanced positions of single wave parameters. Two dimensional values of balanced position may be presented as a one dimensional value after weighting of the matrix cells. The signal processing method may be used for more optimal detection of single pressure waves by means of non-invasive sensor devices.

Correction of barometric pressure based on remote sources of information

Abstract: A system for measuring pressure in the body comprising an implanted device for detecting internal absolute pressure, an external monitor providing barometric (atmospheric) pressure, an acoustic or radio telemetric system and a global positioning system (GPS). The barometric pressure is retrieved from a remote source such as an Internet weather web site or a database containing real-time barometric pressure data for various locations in the world by using the GPS data. The gauge pressure is then derived by subtracting the barometric pressure from the absolute pressure.

Noninvasive blood pressure measurement in mice using pulsed Doppler ultrasound.

Abstract: Existing tail-cuff pressure devices for mice use tail flow sensors that measure only systolic and mean pressure. We developed a method to obtain systolic and diastolic pressure in mice using a pulsed Doppler flow velocity sensor and a tail-cuff and validated the method against pressure signals obtained simultaneously from a fluid-filled catheter. The tail-cuff was pressurized to suprasystolic levels to completely occlude the tail artery and then released gradually. The pressure at which the tail flow reappeared was recorded as systolic and the pressure at which the tail flow became continuous was recorded as diastolic. Regression analysis of tail-cuff pressures over catheter pressures obtained from healthy mice (n = 16) showed a high degree of association (rsys = 0.95, rdia = 0.94, both at p < 0.001). Bland–Altman analysis showed good agreement between the two methods, with a mean difference of −13 ( ± 12 SD) mmHg and 3 ( ± 10 SD) mmHg in the systolic (58 to 250 mmHg) and diastolic (48 to 178 mmHg) pressure measurements, respectively. Bland–Altman plots of tail-cuff blood pressures of a second group of mice (n = 20) showed good agreement between repeated measurements obtained on the same day, but had higher variability between measurements made on different days.

Unsteady Turbine Blade Wake Characteristics

Abstract: The paper presents an experimental investigation of large coherent structures, commonly referred to as “von Karman vortex street”, in the wake of a turbine blade at high subsonic Mach number (M2,is = 0.79) and high Reynolds number (RE = 2.8×106 and their effect on the steady and unsteady pressure and temperature distribution in the wake. Ultra short smoke visualizations and two interferometric measurement techniques, holographic interferometry and white light differential interferometry provide insight into the vortex formation and shedding process. In addition, the interferometric measurement provides quantitative information on the stream wise evolution of the minimum density associated with the vortices and on their lateral spreading. Wake traverses are performed with a four-head fork probe carrying a Kiel probe and a fast response Kulite pressure probe for pressure measurements and a thermo-couple probe and a cold wire resistance probe for temperature measurements. The results confirm the observation of energy separation in the wake as found by other researchers. The experimental data are a unique source for the validation of unsteady Navier-Stokes codes.© 2003 ASME

Optical differential pressure transducer utilizing a bellows and flexure system

Abstract: A pressure transducer that uses a rhomboidal flexure to provide displacement amplification to an optical sensing element is disclosed The transducer includes an optical sensor disposed between sides of the flexure The top portion of the flexure connects to a displacement device, such as a bellows A first pressure port provides a first pressure to the bellows A second pressure, preferably greater than the first pressure, is ported into a housing containing the flexure, which tends to compress the bellows and pull apart or expand the flexure Such expansion pinches or compresses the optical sensing element between the sides of the flexure, and in particular stresses an optical sensing element containing a fiber Bragg grating Assessing the Bragg reflection wavelength of the grating allows the differential pressure to be determined, although the transducer can also be used to sense an absolute pressure A temperature compensation scheme, including the use of additional fiber Bragg gratings and thermal compensators axially positioned to counteract thermal effects of the optical sensing element, is also disclosed

Toe pressure measurements compared to ankle artery pressure measurements.

Abstract: The Trans-Atlantic Inter-Society Consensus (TASC)-recommended absolute toe pressure is < 30-50 mm Hg for definition of chronic critical limb ischemia (CLI). Toe pressures can be measured by different techniques. The authors analyzed the clinical use of the Doppler technique and an automatic device with optical sensors and estimated their value in documentation of chronic critical limb ischemia compared to ankle artery pressures. Three different investigations were performed: (1) In 16 healthy subjects the digital artery pressures were measured by using 3 different optical sensors (transmission, reflection, and microcirculation sensor) and compared to the systolic brachial pressure. (2) In 50 patients with and without peripheral arterial occlusive disease the toe pressures at digits 1 and 2 of both feet were determined by Doppler technique (8 MHz) and by optical sensors (cuff width constant 1.5 cm) and were compared to the ankle artery pressure determined by Doppler technique. (3) In 175 patients the toe pressures were measured at 1 toe and the ankle artery pressures were determined. In this group they estimated the clinical use of the toe pressure in regard to the definition of CLI (toe pressure < 50 mm Hg) compared to the ankle pressure < 70 mm Hg. The digital artery pressures measured with the different optical sensors, and the systolic brachial pressures were not significantly different and the correlation coefficients were around 0.7. In 21 of 50 patients the toe pressure at D1 and D2 could not be measured by Doppler technique because with the applied cuff no Doppler signal could be detected at the tip of the toe, but in 24 of these 29 patients the optical measurement was possible. Mean toe pressures at D1 were 108 +/- 45 mm Hg and D2 102 +/- 45 mm Hg, which were statistically not different. The correlation coefficient for the highest ankle artery pressure and the highest toe pressure determined by the Doppler technique was 0.389; for the highest ankle artery pressure and the toe pressure measured by the optical sensors it was 0.369, and for the toe pressures measured by Doppler technique and the optical sensors it was 0.506. Defining systolic ankle artery pressure < or = 50 to 70 mm Hg as the golden standard for CLI, the sensitivity of optical toe pressure measurement for the detection of CLI was 8%, the specificity was 96%, the positive predictive value 12%, and the negative predictive value was 94%. Independent of technique the absolute systolic toe pressures did not correlate with the absolute systolic ankle pressures. The optical measurement was more suitable for toe pressure measurement because it could be used in 90% of all patients. All in all, toe pressure measurements are more useful to exclude CLI than to prove it.

Method for reservoir navigation using formation pressure testing measurement while drilling

Abstract: A formation pressure testing while drilling device on a bottomhole assembly (21) makes measurements of fluid pressure during drilling of a borehole (15). Based on the pressure measurements, drilling direction can be altered to maintain the wellbore (15) in a desired relation to a fluid contact. Acoustic transmitters and/or receivers (59,61) on the bottomhole assembly can provide additional information about bed boundaries, faults and gas-water contacts.

An optical fiber infrasound sensor: a new lower limit on atmospheric pressure noise between 1 and 10 Hz.

Abstract: A new distributed sensor for detecting pressure variations caused by distant sources has been developed. The instrument reduces noise due to air turbulence in the infrasound band by averaging pressure along a line by means of monitoring strain in a long tubular diaphragm with an optical fiber interferometer. Above 1 Hz, the optical fiber infrasound sensor (OFIS) is less noisy than sensors relying on mechanical filters. Records collected from an 89-m-long OFIS indicate a new low noise limit in the band from 1 to 10 Hz. Because the OFIS integrates pressure variations at light-speed rather than the speed of sound, phase delays of the acoustical signals caused by the sensor are negligible. Very long fiber-optic sensors are feasible and hold the promise of better wind-noise reduction than can be achieved with acoustical-mechanical systems.

Unsteady, 3-Dimensional Flow Measurement Using a Miniature Virtual 4 Sensor Fast Response Aerodynamic Probe (FRAP)

Abstract: This paper introduces the new fast response aerodynamic probe, which was recently developed at the ETH Zurich. The technique provides time-resolved, three-dimensional flow measurements using the virtual four sensor technique. The concept and the evaluation of the virtual four sensor probe is discussed in detail. The basic results consist of yaw and pitch flow angles as well as the total and static pressure. They combine to form the unsteady, three dimensional flow vector. The outer diameter of the cylindrical probe head was miniaturized to 0.84mm, hence probe blockage effects as well as dynamic lift effects are reduced. The shape of the probe head was optimized in view of the manufacturing process as well as aerodynamic considerations. The optimum geometry for pitch sensitivity was found to be a cylindrical surface with the axis perpendicular to the probe shaft. The internal design of the probes led to a sensor cavity eigenfrequency of 44kHz for the yaw sensitive and 34kHz for the pitch sensitive probe. Data acquisition is done with a fully automated traversing system, which moves the probe within the test rig and samples the signal with a PC-based A/D-board. An error analysis implemented into the data reduction routines revealed acceptable accuracy for flow angles as well as pressures for many turbomachinery flows. Depending on the dynamic head of the application the yaw angle is accurate within ±0.35° and pitch angle within ±0.7°. In the final section, a comparison of time averaged results to five hole probe measurements is discussed. The advantages of the new probe, beside its unique smallness, are the complete unsteady kinematic information and the improved recording of unsteady total pressure measurement as it is pointed out in a comparison against a 2D virtual three sensor probe.Copyright © 2003 by ASME

Method and device for treating the cases of paranasal sinusitis

Abstract: FIELD: medicine; medical engineering. SUBSTANCE: method involves tightly sealing the nasal and rhinopharyngeal cavity with soft palatine that is pressed against the posterior pharyngeal wall by contracting respiratory muscles without performing exhalation at the first stage. Rarefaction to 60-85 kPa is created in nasal cavity and rhinopharynx that is equalized 5-15 s later by supplying air under atmospheric pressure. The second stage involves tightly sealing the nasal and rhinopharyngeal cavity for 10-15 s, sucking air and nasal cavity matter from one nose half off and supplying aerosol containing medicament into the other half under pressure higher than usual. The third stage involves tightly sealing the nasal cavity and rhinopharynx and reducing pressure to 60 kPa via the other half of the nose opposite to one in sinuses of which medicament is to be supplied. 1-2 s later, aerosol containing medicament is introduced into the injured half of nose under pressure of 140 kPa. The pressure is dropped to 80 kPa after having done sealing and quickly equalizing it with atmospheric pressure by supplying air or aerosol containing medicament into the other nose half under pressure of 120 kPa at the fourth stage. When needed, each stage is to be repeated using obturator. Pressure reduction or increase is carried out by the same value. Device has suction line having rarefaction source, reservoir for accumulating exudate, connection tube and delivery line having pressure source and connection tube. The suction line additionally has obturating olive, filter, vacuum manometer, distributor unit, receiver, vacuum-gage and rarefaction regulator. The obturating olive is connected to rarefaction source via the connection tube mounted in series, reservoir for accumulating exudate, filter, distributor unit, receiver and rarefaction regulator. The vacuum manometer is mounted between the receiver and rarefaction regulator. The delivery line additionally has pressure control unit, manometer, receiver, dosing unit, obturating olive and sprayer. Pressure source is connected to the obturating olive via pressure control unit, receiver, distributor unit, connection tube and sprayer connected in series. The manometer is mounted between the pressure control unit and receiver. The dosing unit is connected to the sprayer. EFFECT: improved quality of pathological content evacuation from nasal appendage sinuses; facilitated medicament delivery to the nasal appendage sinuses. 5 cl; 2 dwg

Measurement of Pressure Drop in a Full-Scale Fuel Assembly of a Liquid Metal Reactor

Abstract: An experimental study has been carried out to measure the pressure drop in a 271-pin fuel assembly of a liquid metal reactor. The rod pitch to rod diameter ratio~ P/D! of the fuel assembly is 1.2 and the wire lead length to rod diameter ratio~H/D! is 24.84. Measurements are made for five different sections in a fuel assembly; inlet orifice, fuel assembly inlet, wire-wrapped fuel assembly, fuel assembly outlet and fuel assembly upper region. A series of water experiments have been conducted changing flow rate and water temperature. It is shown that the pressure drops in the inlet orifice and in the wire-wrapped fuel assembly are much larger than those in other regions. The measured pressure drop data in a wire-wrapped fuel assembly region is compared with the existing four correlations. It is shown that the correlation proposed by Cheng and Todreas fits best with the present experimental data among the four correlations considered@DOI: 10.1115/1.1565076# The liquid metal reactor core consists of several fuel assemblies contained in a hexagonal shaped duct. There is no flow exchange between ducts. In order to efficiently extract the heat generated in a fuel assembly, it is important to distribute the flow rate among the fuel assemblies and to maintain the temperature distribution properly. The distribution of coolant flow rate in each fuel assembly is determined by the heat generation in each fuel assembly after the required whole coolant flow rate is determined to meet the reactor power. The reactor core is divided into a certain number of groups that have the same coolant flow rate, and then the temperature distribution of the fuel assembly is calculated and the coolant flow rate in each group is adjusted to have the same degree of peak temperature in the fuel rod. Then, the orifice in the bottom region of the fuel assembly is designed following the pressure drop of the fuel assembly. Thus, the information of pressure drop in a fuel assembly is very important in the thermal hydraulic design of the reactor core. The individual fuel assembly consists of inlet orifice, fuel assembly inlet, wire-wrapped fuel assembly, fuel assembly outlet and fuel assembly upper region. The primary objective of the present study is to measure the pressure drops in these regions for the design of Korea Advanced Liquid Metal Reactor ~KALIMER!. A series of experiments are conducted to measure the pressure drops in these regions. The relative magnitude of pressure drops in these regions is investigated from the measured data. As will be shown later, the pressure drops in the inlet orifice and in the wire-wrapped fuel assembly is much larger than the pressure drops in other regions. The design of the inlet orifice for KALIMER is not determined yet and the inlet orifice used in the present measurement is only a tentative design. Thus, the primary emphasis of the present study is placed on the analysis of pressure drop in the wire-wrapped fuel assembly. In order to maintain a proper spacing between fuel pins and promote the coolant mixing, several types of spacers are proposed. Among the various spacers the helical-type wire-spacers are widely used in the liquid metal reactor ~LMR! and are adopted in the design of KALIMER. However, the existence of spacers between fuel pins causes the increase of hydraulic resistance,