WorldWideScience

Sample records for volume-dependent measurement technique

  1. Urban Run-off Volumes Dependency on Rainfall Measurement Method

    DEFF Research Database (Denmark)

    Pedersen, L.; Jensen, N. E.; Rasmussen, Michael R.;

    2005-01-01

    Urban run-off is characterized with fast response since the large surface run-off in the catchments responds immediately to variations in the rainfall. Modeling such type of catchments is most often done with the input from very few rain gauges, but the large variation in rainfall over small area...... resolutions and single gauge rainfall was fed to a MOUSE run-off model. The flow and total volume over the event is evaluated.......Urban run-off is characterized with fast response since the large surface run-off in the catchments responds immediately to variations in the rainfall. Modeling such type of catchments is most often done with the input from very few rain gauges, but the large variation in rainfall over small areas...... suggests that rainfall needs to be measured with a much higher spatial resolution (Jensen and Pedersen, 2004). This paper evaluates the impact of using high-resolution rainfall information from weather radar compared to the conventional single gauge approach. The radar rainfall in three different...

  2. Process measuring techniques; Prozessmesstechnik

    Energy Technology Data Exchange (ETDEWEB)

    Freudenberger, A.

    2000-07-01

    This introduction into measurement techniques for chemical and process-technical plant in science and industry describes in detail the methods used to measure basic quantities. Most prominent are modern measuring techniques by means of ultrasound, microwaves and the Coriolis effect. Alongside physical and measuring technique fundamentals, the practical applications of measuring devices are described. Calculation examples are given to illustrate the subject matter. The book addresses students of physical engineering, process engineering and environmental engineering at technical schools as well as engineers of other disciplines wishing to familiarize themselves with the subject of process measurement techniques. (orig.) [German] Diese Einfuehrung in die Messtechnik fuer chemische und verfahrens-technische Forschungs- und Produktionsanlagen beschreibt ausfuehrlich die Methoden zur Messung der Basisgroessen. Moderne Messverfahren mit Ultraschall, Mikrowellen und Coriolis-Effekt stehen dabei im Vordergrund. Beruecksichtigung finden sowohl die physikalischen und messtechnischen Grundlagen als auch die praktischen Anwendungen der Geraete. Berechnungsbeispiele dienen der Erlaeuterung und Vertiefung des Stoffes. Angesprochen sind Studenten der Ingenieurstufengaenge Physikalische Technik und Verfahrens- und Umwelttechnik an Fachhochschulen als auch Ingenieure anderer Fachrichtungen, die sich in das Gebiet der Prozessmesstechnik einarbeiten wollen. (orig.)

  3. New measurements techniques

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni

    of the pressure encountered by the ‘sensing’ light when traveling through the acoustic field. Far from being a limitation, this integral principle is exploited for sound field visualization using tomography. The most innovative contribution of this PhD project is the applicability of the acousto-optic measuring......Acoustic measurements are traditionally based on transducers, and in particular, the most advanced measurement techniques are nowadays based on transducer arrays. This poses a fundamental problem, namely the influence of the transducer itself on the actual properties of sound when the transducer...... is immersed into the sound field. Typically, this influence is assumed to be negligible when the size of the transducer is small compared to the wavelength of the sound wave, or is rendered negligible by using a transducerbased correction that depends on the frequency. Either solution introduces additional...

  4. Remote Attitude Measurement Techniques.

    Science.gov (United States)

    1982-12-01

    are other factors which will influence the selection of the communications means. One major factor is the selection of the technology to be used. Aside...electrooptical devices with partitioned focal planes, and the char- acteristics of these techniques influence how the focal planes are partitioned. G. FOCAL...a televison camera). The incident illumination produces a non-uniformity on the scanned side of the sensitive material which can be modeled as an

  5. Helium II level measurement techniques

    Science.gov (United States)

    Celik, D.; Hilton, D. K.; Zhang, T.; Van Sciver, S. W.

    2001-05-01

    In this paper, a survey of cryogenic liquid level measurement techniques applicable to superfluid helium (He II) is given. The survey includes both continuous and discrete measurement techniques. A number of different probes and controlling circuits for this purpose have been described in the literature. They fall into one of the following categories: capacitive liquid level gauges, superconducting wire liquid level gauges, thermodynamic (heat transfer-based) liquid level gauges, resistive gauges, ultrasound and transmission line-based level detectors. The present paper reviews these techniques and their suitability for He II service. In addition to these methods, techniques for measuring the total liquid volume and mass gauging are also discussed.

  6. Optical pulses, lasers, measuring techniques

    CERN Document Server

    Früngel, Frank B A

    1965-01-01

    High Speed Pulse Technology: Volume II: Optical Pulses - Lasers - Measuring Techniques focuses on the theoretical and engineering problems that result from the capacitor discharge technique.This book is organized into three main topics: light flash production from a capacitive energy storage; signal transmission and ranging systems by capacitor discharges and lasers; and impulse measuring technique. This text specifically discusses the air spark under atmospheric conditions, industrial equipment for laser flashing, and claims for light transmitting system. The application of light impulse sign

  7. Thermal measurements and inverse techniques

    CERN Document Server

    Orlande, Helcio RB; Maillet, Denis; Cotta, Renato M

    2011-01-01

    With its uncommon presentation of instructional material regarding mathematical modeling, measurements, and solution of inverse problems, Thermal Measurements and Inverse Techniques is a one-stop reference for those dealing with various aspects of heat transfer. Progress in mathematical modeling of complex industrial and environmental systems has enabled numerical simulations of most physical phenomena. In addition, recent advances in thermal instrumentation and heat transfer modeling have improved experimental procedures and indirect measurements for heat transfer research of both natural phe

  8. Atmospheric Ice Accretion Measurement Techniques

    Directory of Open Access Journals (Sweden)

    M Virk

    2016-09-01

    Full Text Available Atmospheric icing on structures has proven to be an area of concern in many cold climate geographical regions like arctic and alpine. Difficulties encountered by the communication, construction and power industries in these areas are the subject of intense investigations for researchers from decades. Three main methods of investigation are generally employed by researchers to study atmospheric ice accretion on structures: a continuous field measurements, b lab based simulations using icing wind tunnel & c numerical modelling. This paper presents a brief review study of various techniques to understand and measure the atmospheric ice accretion on structures, anti/de icing techniques and important parameters for numerical modelling of atmospheric ice accretion.

  9. A measurement technique for hydroxyacetone

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, P.J.

    1999-10-04

    Hydroxyacetone (HA) is mainly produced in the atmosphere from oxidation of hydrocarbons of the type, CH{sub 3}(R)C{double{underscore}bond}CH{sub 2}. Tuazon and Atkinson (1990) reported HA yield of 41% from the OH-initiated oxidation of methacrolein in the presence of NOx. Since methacrolein is a major product of isoprene oxidation (Carter and Atkinson, 1996), isoprene, a key biogenic hydrocarbon, is therefore expected to be an important source for HA. Consequently, knowledge of ambient concentration of HA would provide information needed to examine the applicability of isoprene reaction mechanisms developed in laboratory and to assess the contribution of isoprene to photooxidant production. The commonly used GC-FID technique involving cryo-focusing is unsuitable for HA owing to HA's thermal instability. When subjected to a temperature of 100 C for only a few seconds, HA was found to disappear completely. Since HA is highly soluble in water, the authors developed a wet chemical technique similar in principle to the one they reported earlier, namely, derivatization following liquid scrubbing. To increase the sensitivity, they adopted a fluorescence detection scheme based on o-phthaldialdehyde (OPA) chemistry. The technique was deployed in the field during two measurement periods at a NARSTO site located on Long Island, New York. The authors report the principle and the operation of this technique and the results obtained from these field studies.

  10. Developments in luminescence measurement techniques

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Bøtter-Jensen, L.; Denby, Phil M.

    2006-01-01

    We report on our continuing investigation and development of new measurement facilities for use in irradiation, optical stimulation and luminescence signal detection; these facilities have potential application to all forms of luminescence-based retrospective dosimetry, and are particularly...... intended for use with the Riso TL/OSL reader. We have investigated the potential of new more powerful blue (455 nm) and green (530nm) LEDs, and of gated counting combined with pulsed stimulation light techniques using conventional LEDs. Measurement of time-resolved OSL has resulted in a method of real......; both types are very stable and reproducible. Other recent developments include the modification of a Riso reader to measure both thermally and optically stimulated electrons (TSE and OSE) from granular or chip phosphors. (c) 2006 Elsevier Ltd. All rights reserved....

  11. A MEASUREMENT TECHNIQUE FOR HYDROXYACETONE.

    Energy Technology Data Exchange (ETDEWEB)

    KLOTZ,P.J.

    1999-10-04

    Hydroxyacetone (HA) is mainly produced in the atmosphere from oxidation of hydrocarbons of the type, CH{sub 3}(R)C=CH{sub 2}. Tuazon and Atkinson (1990) reported HA yield of 41% from the OH-initiated oxidation of methacrolein in the presence of NO{sub x}. Since methacrolein is a major product of isoprene oxidation (Carter and Atkinson, 1996), isoprene, a key biogenic hydrocarbon, is therefore expected to be an important source for HA. Consequently, knowledge of ambient concentration of HA would provide information needed to examine the applicability of isoprene reaction mechanisms developed in laboratory and to assess the contribution of isoprene to photooxidant production. The commonly used GC-FID technique involving cryo-focusing is unsuitable for HA owing to HA's thermal instability. When subjected to a temperature of 100 C for only a few seconds, HA was found to disappear completely. Since HA is highly soluble in water (it's Henry's law constant being {approx}2 x 10{sup 4} M atm{sup -1} at 20 C, Zhou and Lee, unpublished data), we developed a wet chemical technique similar in principle to the one we reported earlier (Lee and Zhou, 1993), namely, based on derivatization following liquid scrubbing. To increase the sensitivity, we adopted a fluorescence detection scheme based on o-phthaldialdehyde (OPA) chemistry. The technique was deployed in the field during two measurement periods at a NARSTO site located on Long Island (LI), New York. We report the principle and the operation of this technique and the results obtained from these field studies.

  12. POSIVA groundwater flow measuring techniques

    Energy Technology Data Exchange (ETDEWEB)

    Oehberg, A. [Saanio and Riekkola Consulting Engineers, Helsinki (Finland); Rouhiainen, P. [PRG-Tec Oy (Finland)

    2000-08-01

    Posiva Oy has carried out site characterisation for the final disposal of spent nuclear fuel in Finland since 1987. To meet the demanding needs to measure the hydraulic parameters in bedrock Posiva launched development of new flowmeter techniques including measuring methods and equipment in co-operation with PRG-Tec Oy. The techniques have been tested and used in the ongoing site investigations in Finland, in the underground Hard Rock Laboratory (HRL) at Aespoe in Sweden and in URL in Canada. The new methods are called difference flow and transverse flow methods. The difference flow method includes two modes, normal and detailed flow logging methods. In the normal mode the flow rate measurement is based on thermal pulse and thermal dilution methods, in the detailed logging mode only on thermal dilution method. The measuring ranges for flow rate with thermal pulse and dilution methods are 0.1-10 ml/min and 2-5000 ml/min, respectively. The difference flow method(normal mode) for small flows (0.1-10 ml/min) is based on measuring the pulse transit time and direction of a thermal pulse in the sensor. For high flows (2-5000 ml/min) the method is based on thermal dilution rate of a sensor. Direction is measured with monitoring thermistors. Inflow or outflow in the test interval is created due to natural or by pumping induced differences between heads in the borehole water and groundwater around the borehole. The single point resistance (and the temperature of borehole water) measurement is carried out simultaneously with the difference flow measurements, both in normal and detailed flow logging modes, while the tool is moving. The result is utilised for checking the exact depth of the tool. As the result a continuous log is obtained from which single fractures can be detected. The transverse flowmeter is able to measure the groundwater flow across a borehole. A special packer system guides the flow through the flow sensors. Four inflatable seals between conventional

  13. An acoustic mode measurement technique

    Science.gov (United States)

    Joppa, P. D.

    1984-10-01

    Turbomachinery noise propagates in aircraft jet engine ducts in a complicated manner. Measurement of this propagation is useful both to identify source mechanisms and to design efficient linings. A practical method of making these measurements has been developed, using linear arrays of equally spaced microphones mounted flush with the duct wall. Circumferential or axial arrays are analyzed by spatial Fourier transform, giving sound level as a function of spinning order or axial wavenumber respectively. Complex demodulation is used to acquire data in a modest bandwidth around a high frequency of interest. A joint NASA/Boeing test of the system used 32 microphones in a JT15D turbofan engine inlet. A 400-Hz bandwidth centered at blade passage frequency and at half blade passage frequency was studied. The theoretically predicted modes were clearly seen at blade passage frequency; broadband noise at half blade passage frequency was biased towards modes corotating with the fan. Interference between similar modes was not a significant problem. A lining design study indicated a 15 percent improvement in lining efficiency was possible when mode data were used, for this particular engine. The technique has proven reliable and useful for source diagnostics and lining design.

  14. Surveying techniques in vibration measurement

    Directory of Open Access Journals (Sweden)

    Kuras Przemyslaw

    2015-01-01

    Full Text Available In order to determine the actual dynamic characteristics of engineering structures, it is necessary to perform direct measurements. The paper focuses on the problem of using various devices to measure vibration, with particular emphasis on surveying instruments. The main tool used in this study is the radar interferometer, which has been compared to: robotic total station, GNSS receivers and sensors (accelerometer and encoder. The results of four dynamic experiments are presented. They were performed on: industrial chimney, drilling tower, railway bridge and pedestrian footbridge. The obtained results have been discussed in terms of the requirements imposed by the standard ISO 4866:2010.

  15. Advanced in-flight measurement techniques

    CERN Document Server

    Lawson, Nicholas; Jentink, Henk; Kompenhans, Jürgen

    2013-01-01

    The book presents a synopsis of the main results achieved during the 3 year EU-project "Advanced Inflight Measurement Techniques (AIM)" which applied advanced image based measurement techniques to industrial flight testing. The book is intended to be not only an overview on the AIM activities but also a guide on the application of advanced optical measurement techniques for future flight testing. Furthermore it is a useful guide for engineers in the field of experimental methods and flight testing who face the challenge of a future requirement for the development of highly accurate non-intrusive in-flight measurement techniques.

  16. Measurement Error with Different Computer Vision Techniques

    Science.gov (United States)

    Icasio-Hernández, O.; Curiel-Razo, Y. I.; Almaraz-Cabral, C. C.; Rojas-Ramirez, S. R.; González-Barbosa, J. J.

    2017-09-01

    The goal of this work is to offer a comparative of measurement error for different computer vision techniques for 3D reconstruction and allow a metrological discrimination based on our evaluation results. The present work implements four 3D reconstruction techniques: passive stereoscopy, active stereoscopy, shape from contour and fringe profilometry to find the measurement error and its uncertainty using different gauges. We measured several dimensional and geometric known standards. We compared the results for the techniques, average errors, standard deviations, and uncertainties obtaining a guide to identify the tolerances that each technique can achieve and choose the best.

  17. MEASUREMENT ERROR WITH DIFFERENT COMPUTER VISION TECHNIQUES

    Directory of Open Access Journals (Sweden)

    O. Icasio-Hernández

    2017-09-01

    Full Text Available The goal of this work is to offer a comparative of measurement error for different computer vision techniques for 3D reconstruction and allow a metrological discrimination based on our evaluation results. The present work implements four 3D reconstruction techniques: passive stereoscopy, active stereoscopy, shape from contour and fringe profilometry to find the measurement error and its uncertainty using different gauges. We measured several dimensional and geometric known standards. We compared the results for the techniques, average errors, standard deviations, and uncertainties obtaining a guide to identify the tolerances that each technique can achieve and choose the best.

  18. Experimental Techniques for Thermodynamic Measurements of Ceramics

    Science.gov (United States)

    Jacobson, Nathan S.; Putnam, Robert L.; Navrotsky, Alexandra

    1999-01-01

    Experimental techniques for thermodynamic measurements on ceramic materials are reviewed. For total molar quantities, calorimetry is used. Total enthalpies are determined with combustion calorimetry or solution calorimetry. Heat capacities and entropies are determined with drop calorimetry, differential thermal methods, and adiabatic calorimetry . Three major techniques for determining partial molar quantities are discussed. These are gas equilibration techniques, Knudsen cell methods, and electrochemical techniques. Throughout this report, issues unique to ceramics are emphasized. Ceramic materials encompass a wide range of stabilities and this must be considered. In general data at high temperatures is required and the need for inert container materials presents a particular challenge.

  19. Measurement of solid concentration using Terahertz technique

    Institute of Scientific and Technical Information of China (English)

    Liu Yi'an; Huang Zhiyao; Ji Haifeng; Wang Baoliang; Li Haiqing

    2007-01-01

    Terahertz(THz)technique is a new measurement technique that has emerged in recent years. For the measurement of solid concentration, a radiation attenuation method and a phase delay method were developed, which are based on the Beer-Lambert law. Experimental work was carried out on a terahertz time-domain spectroscopy system (THz-TDS). Results obtained verify that the terahertz technique may provide a possible new solution to the problem of solid concentration measurement and the two proposed measurement methods are effective. Experiment results also indicate that the phase delay method is more accurate than the radiation attenuation method and the size of the particles affects the measurement results of both methods.

  20. Multidirectional mobilities: Advanced measurement techniques and applications

    Science.gov (United States)

    Ivarsson, Lars Holger

    Today high noise-and-vibration comfort has become a quality sign of products in sectors such as the automotive industry, aircraft, components, households and manufacturing. Consequently, already in the design phase of products, tools are required to predict the final vibration and noise levels. These tools have to be applicable over a wide frequency range with sufficient accuracy. During recent decades a variety of tools have been developed such as transfer path analysis (TPA), input force estimation, substructuring, coupling by frequency response functions (FRF) and hybrid modelling. While these methods have a well-developed theoretical basis, their application combined with experimental data often suffers from a lack of information concerning rotational DOFs. In order to measure response in all 6 DOFs (including rotation), a sensor has been developed, whose special features are discussed in the thesis. This transducer simplifies the response measurements, although in practice the excitation of moments appears to be more difficult. Several excitation techniques have been developed to enable measurement of multidirectional mobilities. For rapid and simple measurement of the loaded mobility matrix, a MIMO (Multiple Input Multiple Output) technique is used. The technique has been tested and validated on several structures of different complexity. A second technique for measuring the loaded 6-by-6 mobility matrix has been developed. This technique employs a model of the excitation set-up, and with this model the mobility matrix is determined from sequential measurements. Measurements on ``real'' structures show that both techniques give results of similar quality, and both are recommended for practical use. As a further step, a technique for measuring the unloaded mobilities is presented. It employs the measured loaded mobility matrix in order to calculate compensation forces and moments, which are later applied in order to compensate for the loading of the

  1. High-voltage test and measuring techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hauschild, Wolfgang; Lemke, Eberhard

    2014-04-01

    Reflects the unit of both HV testing and measuring technique. Intended as an ''application guide'' for the relevant IEC standards. Refers also to future trends in HV testing and measuring technique. With numerous illustrations. It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  2. Optical measurement techniques - A push for digitization

    Science.gov (United States)

    Kulkarni, Rishikesh; Rastogi, Pramod

    2016-12-01

    Over the years, optical measurement techniques have been the problem-solving backbone of many engineering applications such as nondestructive testing of materials, measurement of various material properties, structural analysis and experimental mechanics [1-3]. Probably the most important advantage associated with any optical measurement system over other systems is its non-contact type of measurement capability. Apart from their non-contact nature, the optical measurement systems are capable of providing full-field measurements at scales ranging from milli-meters to nano-meters.

  3. Review of air flow measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    McWilliams, Jennifer

    2002-12-01

    Airflow measurement techniques are necessary to determine the most basic of indoor air quality questions: ''Is there enough fresh air to provide a healthy environment for the occupants of the building?'' This paper outlines airflow measurement techniques, but it does not make recommendations for techniques that should be used. The airflows that will be discussed are those within a room or zone, those between rooms or zones, such as through doorways (open or closed) or passive vents, those between the building and outdoors, and those through mechanical air distribution systems. Techniques that are highlighted include particle streak velocimetry, hot wire anemometry, fan pressurization (measuring flow at a given pressure), tracer gas, acoustic methods for leak size determination, the Delta Q test to determine duct leakage flows, and flow hood measurements. Because tracer gas techniques are widely used to measure airflow, this topic is broken down into sections as follows: decay, pulse injection, constant injection, constant concentration, passive sampling, and single and multiple gas measurements for multiple zones.

  4. VALUATION TECHNIQUES USED IN FAIR VALUE MEASUREMENT

    OpenAIRE

    Cristina-Aurora, BUNEA-BONTAS

    2013-01-01

    Valuation of assets and liabilities involves significant judgements and estimates, especially when fair value measurement is required. Currently, IFRS 13 Fair Value Measurement offers a single and more comprehensive source of guidance that is applied to almost all fair value estimates. When measuring fair value of fixed assets, intangible assets, specified financial assets or liabilities, different valuation techniques may be used: the market approach, the cost approach and the income appr...

  5. A review on creatinine measurement techniques.

    Science.gov (United States)

    Mohabbati-Kalejahi, Elham; Azimirad, Vahid; Bahrami, Manouchehr; Ganbari, Ahmad

    2012-08-15

    This paper reviews the entire recent global tendency for creatinine measurement. Creatinine biosensors involve complex relationships between biology and micro-mechatronics to which the blood is subjected. Comparison between new and old methods shows that new techniques (e.g. Molecular Imprinted Polymers based algorithms) are better than old methods (e.g. Elisa) in terms of stability and linear range. All methods and their details for serum, plasma, urine and blood samples are surveyed. They are categorized into five main algorithms: optical, electrochemical, impedometrical, Ion Selective Field-Effect Transistor (ISFET) based technique and chromatography. Response time, detection limit, linear range and selectivity of reported sensors are discussed. Potentiometric measurement technique has the lowest response time of 4-10 s and the lowest detection limit of 0.28 nmol L(-1) belongs to chromatographic technique. Comparison between various techniques of measurements indicates that the best selectivity belongs to MIP based and chromatographic techniques. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. New optical technique for bulk magnetostriction measurement

    CERN Document Server

    Samata, H; Uchida, T; Abe, S

    2000-01-01

    A new optical technique was applied to the measurement of magnetostriction in bulk samples. This technique utilizes an optical fiber bundle, AC-modulated light and lock-in detection. Deformation of the sample is determined from the ratio of the incident and reflected light intensities. Noise due to the instability of the light source is eliminated by obtaining the ratio of the incident and reflected light intensities, and the noise caused in the detector circuit can be reduced by lock-in detection. The performance of this method was characterized with a series of measurements using a gold film and crystal disks of pure iron and nickel. This technique offers a resolution of 0.5 nm and is sensitive enough to measure magnetostriction as small as 5x10 sup - sup 7 in 1 mm thick samples.

  7. VALUATION TECHNIQUES USED IN FAIR VALUE MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Cristina-Aurora, BUNEA-BONTAS

    2013-12-01

    Full Text Available Valuation of assets and liabilities involves significant judgements and estimates, especially when fair value measurement is required. Currently, IFRS 13 Fair Value Measurement offers a single and more comprehensive source of guidance that is applied to almost all fair value estimates. When measuring fair value of fixed assets, intangible assets, specified financial assets or liabilities, different valuation techniques may be used: the market approach, the cost approach and the income approach. This article reviews these techniques and points out that different valuation practices may provide different results depending on the item being fair valued and on the inputs used. Also it emphasizes that, in particular circumstances, there is the possibility that a certain technique may be more appropriate than other.

  8. Solar Cell Calibration and Measurement Techniques

    Science.gov (United States)

    Bailey, Sheila; Brinker, Dave; Curtis, Henry; Jenkins, Phillip; Scheiman, Dave

    2004-01-01

    The increasing complexity of space solar cells and the increasing international markets for both cells and arrays has resulted in workshops jointly sponsored by NASDA, ESA and NASA. These workshops are designed to obtain international agreement on standardized values for the AMO spectrum and constant, recommend laboratory measurement practices and establish a set of protocols for international comparison of laboratory measurements. A working draft of an ISO standard, WD15387, "Requirements for Measurement and Calibration Procedures for Space Solar Cells" was discussed with a focus on the scope of the document, a definition of primary standard cell, and required error analysis for all measurement techniques. Working groups addressed the issues of Air Mass Zero (AMO) solar constant and spectrum, laboratory measurement techniques, and te international round robin methodology. A summary is presented of the current state of each area and the formulation of the ISO document.

  9. Comparison of cardiac output measurement techniques

    DEFF Research Database (Denmark)

    Espersen, K; Jensen, E W; Rosenborg, D;

    1995-01-01

    Simultaneously measured cardiac output obtained by thermodilution (TD), transcutaneous suprasternal ultrasonic Doppler (DOP), CO2-rebreathing (CR) and the direct Fick method (FI) were compared in eleven healthy subjects in a supine position (SU), a sitting position (SI), and during sitting exercise...... at a workload of 50 W (EX). The agreements between the techniques, two by two, were expressed as the bias calculated as the averaged differences between the techniques. Precision was expressed as the standard deviation of the bias. The overall agreement (bias +/- precision) between TD, DOP and CR respectively...... and CR, respectively, and TD were 2.5 +/- 2.2 and 2.6 +/- 1.6 l/min. The overall agreement between DOP and CR was 0.1 +/- 1.6 l/min. In conclusion, TD overestimated cardiac output compared to the other techniques and the poor agreement has to be taken into consideration especially in measures of low...

  10. Ionospheric Measurements Using Environmental Sampling Techniques

    Science.gov (United States)

    Bourdeau, R. E.; Jackson, J. E.; Kane, J. A.; Serbu, G. P.

    1960-01-01

    Two rockets were flown to peak altitudes of 220 km in September 1959 to test various methods planned for future measurements of ionization parameters in the ionosphere, exosphere, and interplanetary plasma. The experiments used techniques which sample the ambient environment in the immediate vicinity of the research vehicle. Direct methods were chosen since indirect propagation techniques do not provide the temperatures of charged particles, are insensitive to ion densities, and cannot measure local electron densities under all conditions. Very encouraging results have been obtained from a preliminary analysis of data provided by one of the two flights. A new rf probe technique was successfully used to determine the electron density profile. This was indicated by its agreement with the results of a companion cw propagation experiment, particularly when the probe data were corrected for the effects of the ion sheath which surrounds the vehicle. The characteristics of this sheath were determined directly in flight by an electric field meter which provided the sheath field, and by a Langmuir probe which measured the total potential across the sheath. The electron temperatures deduced from the Langmuir probe data are greater than the neutral gas temperatures previously measured for the same location and season, but these measurements possibly were taken under different atmospheric conditions. Ion densities were calculated from the ion trap data for several altitudes ranging from 130 to 210 km and were found to be within 20 percent of the measured electron densities.

  11. High-voltage test and measuring techniques

    CERN Document Server

    Hauschild, Wolfgang

    2014-01-01

    It is the intent of this book to combine high-voltage (HV) engineering with HV testing technique and HV measuring technique. Based on long-term experience gained by the authors as lecturer and researcher as well as member in international organizations, such as IEC and CIGRE, the book will reflect the state of the art as well as the future trends in testing and diagnostics of HV equipment to ensure a reliable generation, transmission and distribution of electrical energy. The book is intended not only for experts but also for students in electrical engineering and high-voltage engineering.

  12. Unsteady measurement techniques for turbomachinery flows

    Science.gov (United States)

    Jaffa, Nicholas Andrew

    Accurate unsteady measurements are required for studying the flows in high speed turbomachines, which rely on the interaction between rotating and stationary components. Using statistics of phase locked ensembles simplifies the problem, but accurate frequency response in the 10-100 kHz range significantly limits the applicable techniques. This research advances the state of the art for phase resolved measurement techniques using for high speed turbomachinery flows focusing on the following areas: development, validation, and uncertainty quantification. Four methods were developed and implemented: an unsteady total pressure probe, the multiple overheat hot-wire method, the slanted hot-wire method, and the phase peak yaw hot-wire method. These methods allow for the entire phase locked average flow field to be measured (temperature, pressure, and velocity components, swirl angle, etc.). No trusted reference measurement or representative canonical flow exists for comparison of the phase resolved quantities, making validation challenging. Five different validation exercises were performed to increase the confidence and explore the range of applicability. These exercises relied on checking for consistency with expected flow features, comparing independent measurements, and cross validation with CFD. The combined uncertainties for the measurements were quantified using uncertainty estimates from investigations into the elemental error sources. The frequency response uncertainty of constant temperature hot-wire system was investigated using a novel method of illuminating the wire with a laser pulse. The uncertainty analysis provided estimates for the uncertainty in the measurements as well as showing the sensitivity to various sources of error.

  13. Laser Feedback Technique for Precise Retardation Measurements

    Institute of Scientific and Technical Information of China (English)

    FEI Li-Gang; ZHANG Shu-Lian

    2006-01-01

    @@ A simple and precise retardation measurement based on laser feedback is demonstrated. The measurement principle is based on polarization flipping induced by optical feedback from an external birefringence cavity.The measured wave plate is located in the external cavity. When the length of the external cavity is tuned,the polarization states of laser will flip between two eigenstates, and the position of polarization flipping in one period of intensity modulation will vary with retardation of the wave plate. The duty ratio of two eigenstates is used to determine the retardation. Main advantages of the technique are that it is compact, low cost, fast and flexible. Especially, it is insensitive to a fluctuation of laser intensity and is suitable for on-line measurement. The experimental results have shown that the measurement uncertainty is better than 0.03° in the range 30°-150°.

  14. Pulsed thrust measurements using electromagnetic calibration techniques

    Energy Technology Data Exchange (ETDEWEB)

    Tang Haibin; Shi Chenbo; Zhang Xin' ai; Zhang Zun; Cheng Jiao [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

    2011-03-15

    A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 {mu}N s using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5% when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 {mu}N s average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 {mu}N s with 95% credibility.

  15. Techniques to measure testosterone in the elderly.

    Science.gov (United States)

    Klee, G G; Heser, D W

    2000-01-01

    In today's clinical and research settings, there is an unfortunate lack of consistency for the term "measuring testosterone status." This term is often used to refer to a measure of biologic androgen activity rather than the specific measurement of the chemical concentration of the testosterone steroid molecule. Even the measurements of chemical concentrations show considerable methodologic differences. This is true for measurements in elderly men, as well as in other populations, including women. All of the current methods for measuring total testosterone have limitations, especially with regard to low concentrations. In addition, unresolved questions concerning the active form of the hormone preclude definitive determination of which form of testosterone and which other androgen hormones are best suited for measuring androgen activity. When measurement techniques are compared, the numbers correlate with each other but certainly do not represent the same value. There is a need for a consensus as to which forms of hormones should be measured to best assess androgen status, and there is a need to standardize the procedures used to measure these hormones.

  16. Seminar on Detectors and measurements techniques

    Energy Technology Data Exchange (ETDEWEB)

    Holm, E. (ed.) [Risoe National Lab., Roskilde (Denmark)

    2002-07-01

    A Nordic Seminar on detectors and radionuclide measurement techniques was held in Lund, Sweden, May 3-4, 2001. The objective was to highlight recent progress and problems for techniques to study environmental radioactivity. It covered the aspect of detector sample geometry's and methods for evaluation of gamma gamma pulse height distributions. Within the field of alpha-spectrometric techniques gridded ionisation chambers, semiconductor detectors and a general description for analysis of alpha-particle-spectra were presented. Recent development in mass spectrometric techniques, AMS (Accelerator Mass Spectrometry) and ICPMS (Inductively Coupled Plasma mass Spectrometry) for long-lived radionuclides was described. Principles for analysis of beta particle emitters, especially by liquid scintillation were presented. The seminar also covered radiochemistry such advantages and disadvantages between ion exchange, solvent extraction and extraction chromatography. The use of controlled laboratory conditions for discerning the dynamics of accumulation in organisms was demonstrated. Other techniques such as neutron activation were also shown to be useful analytical tool for certain long-lived radionuclides. The results of the intercalibration exercises within the Nordic countries showed the importance of such analytical quality control. (au)

  17. Surface Wear Measurement Using Optical Correlation Technique

    Science.gov (United States)

    Acinger, Kresimir

    1983-12-01

    The coherent optical correlation technique was applied for measuring the surface wear of a tappet (part of car engine), worn by friction with the camshaft. It was found that maximum correlation intensity decays exponentially with the number of wear cycles (i.e. camshaft revolutions). Tappets of the same make have an identical rate of correlation decay. Tappets of different makes have different rates of correlation decay which are in agreement with observed long term wear.

  18. Single spin measurement using cellular automata techniques

    CERN Document Server

    Perez-Delgado, C A; Cory, D G; Mosca, M; Cappellaro, Paola; Cory, David G.; Mosca, Michele; Perez-Delgado, Carlos A.

    2006-01-01

    We propose an approach for single spin measurement. Our method uses techniques from the theory of quantum cellular automata to correlate a large amount of ancillary spins to the one to be measured. It has the distinct advantage of being efficient, and to a certain extent fault-tolerant. Under ideal conditions, it requires the application of only order of cube root of N steps (each requiring a constant number of rf pulses) to create a system of N correlated spins. It is also fairly robust against pulse errors, imperfect initial polarization of the ancilla spin system, and does not rely on entanglement. We study the scalability of our scheme through numerical simulation.

  19. High resolution temperature measurement technique for measuring marine heat flow

    Institute of Scientific and Technical Information of China (English)

    QIN; YangYang; YANG; XiaoQiu; WU; BaoZhen; SUN; ZhaoHua; SHI; XiaoBin

    2013-01-01

    High resolution temperature measurement technique is one of the key techniques for measuring marine heat flow. Basing on Pt1000 platinum resistance which has the characteristics of high accuracy and good stability, we designed a bridge reversal excitation circuit for high resolution temperature measurement. And the deep ocean floor in-situ test results show that: (1) temperature deviation and peak-to-peak resolution of the first version circuit board (V1) are 1.960-1.990 mK and 0.980-0.995 m Kat 1.2-2.7°C, respectively; and temperature deviation and peak-to-peak resolution of the second circuit board (V2) are 2.260mK and 1.130 mK at 1.2-1.3°C, respectively; (2) During the 2012NSFC-IndOcean cruise, seafloor geothermal gradient at Ind2012HF03,-07 and-12 stations (water depth ranges from 3841 to 4541 m) were successfully measured, the values are 59.1,75.1 and 71.6°C/km, respectively. And the measurement errors of geothermal gradient at these three stations are less than 3.0% in terms of the peak-to-peak resolution. These indicate that the high resolution temperature measurement technique based on Pt1000 platinum resistance in this paper can be applied to marine heat flow measurement to obtain high precision geothermal parameters.

  20. A DGT technique for plutonium bioavailability measurements.

    Science.gov (United States)

    Cusnir, Ruslan; Steinmann, Philipp; Bochud, François; Froidevaux, Pascal

    2014-09-16

    The toxicity of heavy metals in natural waters is strongly dependent on the local chemical environment. Assessing the bioavailability of radionuclides predicts the toxic effects to aquatic biota. The technique of diffusive gradients in thin films (DGT) is largely exploited for bioavailability measurements of trace metals in waters. However, it has not been applied for plutonium speciation measurements yet. This study investigates the use of DGT technique for plutonium bioavailability measurements in chemically different environments. We used a diffusion cell to determine the diffusion coefficients (D) of plutonium in polyacrylamide (PAM) gel and found D in the range of 2.06-2.29 × 10(-6) cm(2) s(-1). It ranged between 1.10 and 2.03 × 10(-6) cm(2) s(-1) in the presence of fulvic acid and in natural waters with low DOM. In the presence of 20 ppm of humic acid of an organic-rich soil, plutonium diffusion was hindered by a factor of 5, with a diffusion coefficient of 0.50 × 10(-6) cm(2) s(-1). We also tested commercially available DGT devices with Chelex resin for plutonium bioavailability measurements in laboratory conditions and the diffusion coefficients agreed with those from the diffusion cell experiments. These findings show that the DGT methodology can be used to investigate the bioaccumulation of the labile plutonium fraction in aquatic biota.

  1. Metrology of vibration measurements by laser techniques

    Science.gov (United States)

    von Martens, Hans-Jürgen

    2008-06-01

    Metrology as the art of careful measurement has been understood as uniform methodology for measurements in natural sciences, covering methods for the consistent assessment of experimental data and a corpus of rules regulating application in technology and in trade and industry. The knowledge, methods and tools available for precision measurements can be exploited for measurements at any level of uncertainty in any field of science and technology. A metrological approach to the preparation, execution and evaluation (including expression of uncertainty) of measurements of translational and rotational motion quantities using laser interferometer methods and techniques will be presented. The realization and dissemination of the SI units of motion quantities (vibration and shock) have been based on laser interferometer methods specified in international documentary standards. New and upgraded ISO standards are reviewed with respect to their suitability for ensuring traceable vibration measurements and calibrations in an extended frequency range of 0.4 Hz to higher than 100 kHz. Using adequate vibration exciters to generate sufficient displacement or velocity amplitudes, the upper frequency limits of the laser interferometer methods specified in ISO 16063-11 for frequencies procedures (i.e. measurement uncertainty 0.05 % at frequencies <= 10 kHz, <= 1 % up to 100 kHz).

  2. Full-field wafer warpage measurement technique

    Science.gov (United States)

    Hsieh, H. L.; Lee, J. Y.; Huang, Y. G.; Liang, A. J.; Sun, B. Y.

    2017-06-01

    An innovative moiré technique for full-field wafer warpage measurement is proposed in this study. The wafer warpage measurement technique is developed based on moiré method, Talbot effect, scanning profiling method, stroboscopic, instantaneous phase-shift method, as well as four-step phase shift method, high resolution, high stability and full-field measurement capabilities can be easily achieved. According to the proposed full-field optical configuration, a laser beam is expanded into a collimated beam with a 2-inch diameter and projected onto the wafer surface. The beam is reflected by the wafer surface and forms a moiré fringe image after passing two circular gratings, which is then focused and captured on a CCD camera for computation. The corresponding moiré fringes reflected from the wafer surface are obtained by overlapping the images of the measuring grating and the reference grating. The moiré fringes will shift when wafer warpage occurs. The phase of the moiré fringes will change proportionally to the degree of warpage in the wafer, which can be measured by detecting variations in the phase shift of the moiré fringes in each detection points on the surface of the entire wafer. The phase shift variations of each detection points can be calculated via the instantaneous phase-shift method and the four-step phase-shift method. By adding up the phase shift variations of each detection points along the radii of the circular gratings, the warpage value and surface topography of the wafer can be obtained. Experiments show that the proposed method is capable of obtaining test results similar to that of a commercial sensor, as well as performing accurate measurements under high speed rotation of 1500rpm. As compared to current warpage measurement methods such as the beam optical method, confocal microscopy, laser interferometry, shadow moiré method, and structured light method, this proposed technique has the advantage of full-field measurement, high

  3. Thermoluminescence measurement technique using millisecond temperature pulses.

    Science.gov (United States)

    Manfred, Michael E; Gabriel, Nicholas T; Yukihara, Eduardo G; Talghader, Joseph J

    2010-06-01

    A measurement technique, pulsed thermoluminescence, is described which uses short thermal pulses to excite trapped carriers leading to radiative recombination. The pulses are obtained using microstructures with approximately 500 micros thermal time constants. The technique has many of the advantages of pulsed optically stimulated luminescence without the need for optical sources and filters to isolate the luminescent signal. Charge carrier traps in alpha-Al(2)O(3):C particles on microheaters were filled using 205 nm light. Temperature pulses of 10 and 50 ms were applied to the heaters and compared with a standard thermoluminescence curve taken at a ramp rate of 5 K s(-1). This produced curves of intensity verses temperature similar to standard thermoluminescence except shifted to higher temperatures. The luminescence of single particles was read multiple times with negligible loss of population. The lower limit of the duration of useful pulses appears to be limited by particle size and thermal contact between the particle and heater.

  4. Progress in automation, robotics and measuring techniques

    CERN Document Server

    Zieliński, Cezary; Kaliczyńska, Małgorzata

    2015-01-01

    This book presents recent progresses in control, automation, robotics, and measuring techniques. It includes contributions of top experts in the fields, focused on both theory and industrial practice. The particular chapters present a deep analysis of a specific technical problem which is in general followed by a numerical analysis and simulation, and results of an implementation for the solution of a real world problem. The presented theoretical results, practical solutions and guidelines will be useful for both researchers working in the area of engineering sciences and for practitioners solving industrial problems.    .

  5. Uncertainty Analysis Technique for OMEGA Dante Measurements

    Energy Technology Data Exchange (ETDEWEB)

    May, M J; Widmann, K; Sorce, C; Park, H; Schneider, M

    2010-05-07

    The Dante is an 18 channel X-ray filtered diode array which records the spectrally and temporally resolved radiation flux from various targets (e.g. hohlraums, etc.) at X-ray energies between 50 eV to 10 keV. It is a main diagnostics installed on the OMEGA laser facility at the Laboratory for Laser Energetics, University of Rochester. The absolute flux is determined from the photometric calibration of the X-ray diodes, filters and mirrors and an unfold algorithm. Understanding the errors on this absolute measurement is critical for understanding hohlraum energetic physics. We present a new method for quantifying the uncertainties on the determined flux using a Monte-Carlo parameter variation technique. This technique combines the uncertainties in both the unfold algorithm and the error from the absolute calibration of each channel into a one sigma Gaussian error function. One thousand test voltage sets are created using these error functions and processed by the unfold algorithm to produce individual spectra and fluxes. Statistical methods are applied to the resultant set of fluxes to estimate error bars on the measurements.

  6. Alternative techniques for beam halo measurements

    CERN Document Server

    Welsch, CP; Burel, B; Lefèvre, T; Chapman, T; Pilon, MJ

    2006-01-01

    In future high intensity, high energy accelerators it must be ensured that particle losses are minimized, as activation of the vacuum chambers or other components makes maintenance and upgrade work time consuming and costly. It is imperative to have a clear understanding of the mechanisms that can lead to halo formation and to have the possibility to test available theoretical models with an adequate experimental setup. Measurements based on optical transition radiation (OTR) are a well-established technique for measurements of the transverse beam profile. However, in order to be suitable for halo measurements as well, the dynamic range of the final image acquisition system needs to be high, being able to cover at least five orders of magnitude in intensity changes. Here, the performance of a standard acquisition system as it is used in the CLIC test facility (CTF3) is compared to a step-by-step measurement with a small movable photo multiplier tube and an innovative camera system based on charge injection de...

  7. Erosive Burning Study Utilizing Ultrasonic Measurement Techniques

    Science.gov (United States)

    Furfaro, James A.

    2003-01-01

    A 6-segment subscale motor was developed to generate a range of internal environments from which multiple propellants could be characterized for erosive burning. The motor test bed was designed to provide a high Mach number, high mass flux environment. Propellant regression rates were monitored for each segment utilizing ultrasonic measurement techniques. These data were obtained for three propellants RSRM, ETM- 03, and Castor@ IVA, which span two propellant types, PBAN (polybutadiene acrylonitrile) and HTPB (hydroxyl terminated polybutadiene). The characterization of these propellants indicates a remarkably similar erosive burning response to the induced flow environment. Propellant burnrates for each type had a conventional response with respect to pressure up to a bulk flow velocity threshold. Each propellant, however, had a unique threshold at which it would experience an increase in observed propellant burn rate. Above the observed threshold each propellant again demonstrated a similar enhanced burn rate response corresponding to the local flow environment.

  8. Donnan membrane technique (DMT) for anion measurement.

    Science.gov (United States)

    Vega, Flora Alonso; Weng, Liping; Temminghoff, Erwin J M; Van Riemsdijk, Willem H

    2010-04-01

    Donnan membrane technique (DMT) is developed and tested for determination of free anion concentrations. Time needed to reach the Donnan membrane equilibrium depends on type of ions and the background. The Donnan membrane equilibrium is reached in 1 day for Cl(-), 1-2 days for NO(3)(-), 1-4 days for SO(4)(2-) and SeO(4)(2-), and 1-14 days for H(2)PO(4)(-) in a background of 2-200 mM KCl or K(2)SO(4). The strongest effect of ionic strength on equilibrium time is found for H(2)PO(4)(-), followed by SO(4)(2-) and SeO(4)(2-), and then by Cl(-) and NO(3)(-). The negatively charged organic particles of fulvic and humic acids do not pass the membrane. Two approaches for the measurement of different anion species of the same element, such as SeO(4)(2-) and HSeO(3)(-), using DMT are proposed and tested. These two approaches are based on transport kinetics or response to ionic strength difference. A transport model that was developed previously for cation DMT is applied in this work to analyze the rate-limiting step in the anion DMT. In the absence of mobile/labile complexes, transport tends to be controlled by diffusion in solution at a low ionic strength, whereas at a higher ionic strength, diffusion in the membrane starts to control the transport.

  9. Basic phenomena utilised in aerosol particle measurement techniques; Hiukkasmittaustekniikoiden perusilmioet

    Energy Technology Data Exchange (ETDEWEB)

    Janka, K. [Dekati Oy, Tampere (Finland)

    2006-10-15

    The project deals with development of basic phenomena and mechanism utilised in aerosol particle measurement techniques. The areas under development are: particle-charging techniques, photoelectric charging, particle concentrating using virtual-impactor technique, and optical characterising techniques of particles. Results will be applied on detection techniques of bioaerosol attract, particle emission sensors for diesel exhaust gases, and widening the application areas of existing measurement techniques. (orig.)

  10. Spectroscopic Measurement Techniques for Aerospace Flows

    Science.gov (United States)

    Danehy, Paul M.; Bathel, Brett F.; Johansen, Craig T.; Cutler, Andrew D.; Hurley, Samantha

    2014-01-01

    The conditions that characterize aerospace flows are so varied, that a single diagnostic technique is not sufficient for its measurement. Fluid dynamists use knowledge of similarity to help categorize and focus on different flow conditions. For example, the Reynolds number represents the ratio of inertial to viscous forces in a flow. When the velocity scales, length scales, and gas density are large and the magnitude of the molecular viscosity is low, the Reynolds number becomes large. This corresponds to large scale vehicles (e.g Airbus A380), fast moving objects (e.g. artillery projectiles), vehicles in dense fluids (e.g. submarine in water), or flows with low dynamic viscosity (e.g. skydiver in air). In each of these cases, the inertial forces dominate viscous forces, and unsteady turbulent fluctuations in the flow variables are observed. In contrast, flows with small length scales (e.g. dispersion of micro-particles in a solid rocket nozzle), slow moving objects (e.g. micro aerial vehicles), flows with low density gases (e.g. atmospheric re-entry), or fluids with a large magnitude of viscosity (e.g. engine coolant flow), all have low Reynolds numbers. In these cases, viscous forces become very important and often the flows can be steady and laminar. The Mach number, which is the ratio of the velocity to the speed of sound in the medium, also helps to differentiate types of flows. At very low Mach numbers, acoustic waves travel much faster than the object, and the flow can be assumed to be incompressible (e.g. Cessna 172 aircraft). As the object speed approaches the speed of sound, the gas density can become variable (e.g. flow over wing of Learjet 85). When the object speed is higher than the speed of sound (Ma > 1), the presences of shock waves and other gas dynamic features can become important to the vehicle performance (e.g. SR-71 Blackbird). In the hypersonic flow regime (Ma > 5), large changes in temperature begin to affect flow properties, causing real

  11. Optical metrology techniques for dimensional stability measurements

    NARCIS (Netherlands)

    Ellis, Jonathan David

    2010-01-01

    This thesis work is optical metrology techniques to determine material stability. In addition to displacement interferometry, topics such as periodic nonlinearity, Fabry-Perot interferometry, refractometry, and laser stabilization are covered.

  12. Optical metrology techniques for dimensional stability measurements

    NARCIS (Netherlands)

    Ellis, Jonathan David

    2010-01-01

    This thesis work is optical metrology techniques to determine material stability. In addition to displacement interferometry, topics such as periodic nonlinearity, Fabry-Perot interferometry, refractometry, and laser stabilization are covered.

  13. Wheatstone bridge technique for magnetostriction measurements.

    Science.gov (United States)

    Sullivan, M

    1980-03-01

    A basic Wheatstone bridge, with additional electronic instrumentation, has been used in the measurement of magnetostriction. This method allows a resolution of approximately 10% on measurements of magnetostrictions less than 0.75 parts per million.

  14. Blood Glucose Measurement Using Bioimpedance Technique

    OpenAIRE

    2014-01-01

    Bioimpedance measurement is gaining importance in wide field of bioresearch and biomedical systems due to its noninvasive nature. Noninvasive measurement method is very important to decrease infection and physical injuries which result due to invasive measurement. This paper presents basic principle of bioimpedance along with its application for blood glucose analysis and effect of frequency on impedance measurement. Input from bioimpedance sensor is given to amplifier and signal conditioner ...

  15. Technique for Measuring Hybrid Electronic Component Reliability

    Energy Technology Data Exchange (ETDEWEB)

    Green, C.C.; Hernandez, C.L.; Hosking, F.M.; Robinson, D.; Rutherford, B.; Uribe, F.

    1999-01-01

    Materials compatibility studies of aged, engineered materials and hardware are critical to understanding and predicting component reliability, particularly for systems with extended stockpile life requirements. Nondestructive testing capabilities for component reliability would significantly enhance lifetime predictions. For example, if the detection of crack propagation through a solder joint can be demonstrated, this technique could be used to develop baseline information to statistically determine solder joint lifelengths. This report will investigate high frequency signal response techniques for nondestructively evaluating the electrical behavior of thick film hybrid transmission lines.

  16. On the theory of SODAR measurement techniques

    DEFF Research Database (Denmark)

    Antoniou, I.; Ejsing Jørgensen, Hans; Bradley, S.

    2003-01-01

    The need for alternative means to measure the wind speed for wind energy purposes has increased with the increase of the size of wind turbines. The cost and the technical difficulties for performing wind speed measurements has also increased with the sizeof the wind turbines, since it is demanded...... of measuring both the wind speed distribution with height and the wind direction. At the same time the SODAR presents a number of serious drawbacks such asthe low number of measurements per time period, the dependence of the ability to measure on the atmospheric conditions and the difficulty of measuring...... that the wind speed has to be measured at the rotor centre of the turbine and the size of both the rotor and the hub height have grown following the increase in the size of the wind turbines. The SODAR (SOundDetection And Ranging) is an alternative to the use of cup anemometers and offers the possibility...

  17. Perspective of remote optical measurement techniques

    OpenAIRE

    Gregorio, Eduard; Rocadenbosch Burillo, Francisco

    2007-01-01

    This article presents an intercomparison between four different ROMTs: differential optical absorption spectroscopy (DOAS), differential absorption LIDAR (DIAL), Fourier transform infrared spectroscopy (FTIR), and tunable diode laser absorption spectroscopy (TDLAS). The main focus is on the TDLAS technique, where the main laser-diode typologies and modulation schemes, namely, wavelength modulation spectroscopy (WMS) and frequency modulation spectroscopy (FMS), are reviewed. At present, new pr...

  18. Donnan Membrane Technique (DMT) for Anion Measurement

    NARCIS (Netherlands)

    Alonso Vega, M.F.; Weng, L.P.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

    2010-01-01

    Donnan membrane technique (DMT) is developed and tested for determination of free anion concentrations. Time needed to reach the Donnan membrane equilibrium depends on type of ions and the background. The Donnan membrane equilibrium is reached in 1 day for Cl-, 1-2 days for NO3-, 1-4 days for SO42-

  19. Blood Glucose Measurement Using Bioimpedance Technique

    Directory of Open Access Journals (Sweden)

    D. K. Kamat

    2014-01-01

    Full Text Available Bioimpedance measurement is gaining importance in wide field of bioresearch and biomedical systems due to its noninvasive nature. Noninvasive measurement method is very important to decrease infection and physical injuries which result due to invasive measurement. This paper presents basic principle of bioimpedance along with its application for blood glucose analysis and effect of frequency on impedance measurement. Input from bioimpedance sensor is given to amplifier and signal conditioner AD5933. AD5933 is then interfaced with microcontroller LPC1768 using I2C bus for displaying reading on LCD. Results can also be stored in database using UART interface of LPC1768.

  20. A Wireless Fluid-Level Measurement Technique

    Science.gov (United States)

    Woodard, Stanley E.; Taylor, Bryant D.

    2006-01-01

    This paper presents the application of a recently developed wireless measurement acquisition system to fluid-level measurement. This type of fluid-level measurement system alleviates many shortcomings of fluid-level measurement methods currently being used, including limited applicability of any one fluid-level sensor design. Measurement acquisition shortcomings include the necessity for power to be supplied to each sensor and for the measurement to be extracted from each sensor via a physical connection to the sensor. Another shortcoming is existing measurement systems require that a data channel and signal conditioning electronics be dedicated to each sensor. Use of wires results in other shortcomings such as logistics needed to add or replace sensors, weight, potential for electrical arcing and wire degradations. The fluid level sensor design is a simple passive inductor-capacitor circuit that is not subject to mechanical failure that is possible when float and lever-arm systems are used. Methods are presented for using the sensor in caustic, acidic or cryogenic fluids. Oscillating magnetic fields are used to power the sensor. Once electrically excited, the sensor produces a magnetic field response. The response frequency corresponds to the amount to fluid within the capacitor s electric field. The sensor design can be modified for measuring the level of any fluid or fluent substance that can be stored in a non-conductive reservoir. The interrogation method for discerning changes in the sensor response frequency is also presented.

  1. A Simple Technique for High Resistance Measurement

    Science.gov (United States)

    Aguilar, Horacio Munguia; Landin, Ramon Ochoa

    2012-01-01

    A simple electronic system for the measurement of high values of resistance is shown. This system allows the measurement of resistance in the range of a few megohm up to 10[superscript 9] [omega]. We have used this system for the evaluation of CdS thin film resistance, but other practical uses in the basic physics laboratory are presented.…

  2. A Simple Technique for High Resistance Measurement

    Science.gov (United States)

    Aguilar, Horacio Munguia; Landin, Ramon Ochoa

    2012-01-01

    A simple electronic system for the measurement of high values of resistance is shown. This system allows the measurement of resistance in the range of a few megohm up to 10[superscript 9] [omega]. We have used this system for the evaluation of CdS thin film resistance, but other practical uses in the basic physics laboratory are presented.…

  3. SPEED ROLLER STAND MEASUREMENT SYSTEM CHECKING TECHNIQUE

    OpenAIRE

    Zybtsev, Y.; I. Marmut

    2011-01-01

    The study has shown that the accuracy of brakes checking by inertial stands depends upon the applied methods of measurement of braking parameters (stand slowing down, braking distance, brakes triggering time, current speed) as well as the methods of metrological checking of measuring system canals.

  4. A simple technique for individual picosecond laser pulse duration measurements

    Science.gov (United States)

    Smith, W. L.; Bechtel, J. H.

    1976-01-01

    We describe here a simple nonlinear optic technique for the measurement of the duration of individual picosecond pulses. The accuracy and relative simplicity of the technique increase with the number of pulses measured. An experimental test of the basis of the technique is described.

  5. Apparatus and techniques for measuring bedload

    Science.gov (United States)

    Hubbell, David Wellington

    1964-01-01

    The need for accurate determinations of the total sediment discharge of particles of bedload size has prompted this investigation of available and possible measuring apparatus and procedures. The accuracy of measurements of sediment discharge made with trap-type samplers is affected by the variability of sampler efficiency, by the oscillatory variation of bedload discharge, and by sampler placement. Equations that were developed for determining total discharge from measured bedioad discharge and measured suspended-sediment discharge are simplest if the bedload apparatus measures only the true bedload. Early bedload samplers are generally unsatisfactory. Recently developed or suggested apparatus include various improved samplers of the pressure-difference type, a pumping sampler, a magnetic sampler, acoustical instruments that measure the magnitude of the sound of particle collisions, an ultrasonic bedload sampler designed to measure and integrate electronically the concentration and velocity, and a tiltmeter designed to measure the total sediment discharge from the ground tilt that results from the passage of flow. All the pressure-difference samplers are improvements over early samplers, but none are void of the inherent shortcomings of trap-type apparatus; probably the Sphinx (Dutch) and VUV (Hungarian) samplers are the most satisfactory. The acoustical instruments are capable of measuring only the relative discharge. The ultrasonic sampler and the tiltmeter are not adequate without further development. Some new possible apparatus and means for measuring or aiding in measuring bedload discharge are small pit samplers, ultrasonic sounders, pressure transducers, and photography. A small pit sampler for measuring bedload discharge was designed to provide self-placement and portability ; however, its practicability and efficiency are undetermined. Exploratory films show that by using slowmotion photography the discharge of particles larger than about pea size can be

  6. Chemonucleolysis technique. New oblique approach requires no measurements.

    Science.gov (United States)

    Romy, M

    1986-01-01

    The author describes a new technique for intradiscal therapy that eliminates the need for measurements. The new technique for entering the lumbar disk for discolysis from the oblique approach is described as simple, accurate and safe.

  7. Altertative trophy measuring techniques for African buffalo

    Directory of Open Access Journals (Sweden)

    S.E. Gandy

    2004-12-01

    Full Text Available The African buffalo is considered the classic African trophy. It is the choice of many hunters who will never go on to hunt any of the other dangerous game animals on the continent. A good trophy is perceived as that of a mature bull with a hardened boss and horn tips that lengthen into sharply pointed hooks. However, indications are that these are the bulls in their breeding prime and there is concern that the continued targeting of these individuals will negatively impact on the population dynamics of the herds, ultimately affecting the sustainability of buffalo hunting. As they age and become postreproductive, the horns broom down, reducing the trophy score under the current measurement systems. A new measuring system is needed that encourages hunters to target the older post-reproductive bulls, instead of those that are still breeding. A random sample of trophies was divided into broomed and non-broomed sub-samples. All key parameters that can be measured in the trophy were measured with a view to identifying the parameters that would allow broomed-down individuals to compete favourably with the non-broomed “classic trophy” in the primary measurement systems, those of Safari Club International and Rowland Ward. An index, created through dividing tip space by the mean of the two individual horn lengths proved to serve the purpose. This factor was then applied to the mean of the SCI and Rowland Ward measurements in the samples. These methods allowed broomed horns to score more points in the record books than non-broomed horns. Boss width and boss space are other possible measurement inclusions that could be considered.

  8. Waste Measurement Techniques For Lean Companies

    Directory of Open Access Journals (Sweden)

    Maciej Pieńkowski

    2014-12-01

    Full Text Available The paper is dedicated to answer the problem of measuring waste in companies, which are implementing Lean Manufacturing concept. Lack of complex identification, quantification an visualization of waste significantly impedes Lean transformation efforts. This problem can be solved by a careful investigation of Muda, Muri and Mura, which represent the essence of waste in the Toyota Production System. Measuring them facilitates complete and permanent elimination of waste in processes. The paper introduces a suggestion of methodology, which should enable company to quantify and visualize waste at a shop floor level.

  9. Compact Models and Measurement Techniques for High-Speed Interconnects

    CERN Document Server

    Sharma, Rohit

    2012-01-01

    Compact Models and Measurement Techniques for High-Speed Interconnects provides detailed analysis of issues related to high-speed interconnects from the perspective of modeling approaches and measurement techniques. Particular focus is laid on the unified approach (variational method combined with the transverse transmission line technique) to develop efficient compact models for planar interconnects. This book will give a qualitative summary of the various reported modeling techniques and approaches and will help researchers and graduate students with deeper insights into interconnect models in particular and interconnect in general. Time domain and frequency domain measurement techniques and simulation methodology are also explained in this book.

  10. Radar Cross-section Measurement Techniques

    Directory of Open Access Journals (Sweden)

    V.G. Borkar

    2010-03-01

    Full Text Available Radar cross-section (RCS is an important study parameter for defence applications specially dealing with airborne weapon system. The RCS parameter guides the detection range for a target and is therefore studied to understand the effectiveness of a weapon system. It is not only important to understand the RCS characteristics of a target but also to look into the diagnostic mode of study where factors contributing to a particular RCS values are studied. This further opens up subject like RCS suppression and stealth. The paper discusses the RCS principle, control, and need of measurements. Classification of RCS in terms of popular usage is explained with detailed theory of RF imaging and inverse synthetic aperture radar (ISAR. The various types of RCS measurement ranges are explained with brief discussion on outdoor RCS measurement range. The RCS calibration plays a critical role in referencing the measurement to absolute values and has been described.The RCS facility at Reseach Centre Imarat, Hyderabad, is explained with some details of different activities that are carried out including RAM evaluation, scale model testing, and diagnostic imaging.Defence Science Journal, 2010, 60(2, pp.204-212, DOI:http://dx.doi.org/10.14429/dsj.60.341

  11. Techniques for measuring customers’ satisfaction in Banks

    Directory of Open Access Journals (Sweden)

    Elena Lidia MELNIC

    2016-07-01

    Full Text Available The major concern of banks today is to recover and maintain customer trust. Customers need to feel that banks are considering their best interests. Customers are seeking for easy and personalized information. They want to better understand their financial situation and to control it. They want to know both the benefits, as well as the risks. Clients want to work with banks that are concerned about them and about their personal goals. However, only an attractive offer of banks is not the key to success today if is not supported by a superior service culture, that can make notable differentiation in the market. Many banks all over the world are systematically measuring how well they treat customers, identifying the factors shaping satisfaction, and changing operations and marketing as a result. Wise banks measure customer satisfaction regularly because it is one key to customer retention.

  12. Techniques for measuring renal transit time

    Energy Technology Data Exchange (ETDEWEB)

    Russell, C.D. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Japanwalla, M. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Khan, S. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Scott, J.W. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Dubovsky, E.V. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States)

    1995-12-01

    A variety of techniques have been used for quantitative estimation of renal transit time. We compared different indices of transit time in a group of 30 patients having baseline and ACE inhibitor technetium-99m mercaptoacetyltriglycine (MAG{sub 3}) renography prior to arteriography: Peak time, mean transit time, and the ratio of background-subtracted counts at 20 min to those at 3 min. Each index was calculated from whole-kidney ROI, cortical ROI, and cortical factor (by factor analysis). The strongest correlations between angiographic percent of stenosis and transit time index were observed for the peak time (Spearman {rho}=0.469, n=53) and for the R20/3 (again {rho}=0.469, n=53) using the whole-kidney ROI and using only the baseline data without captopril. (Spearman`s {rho} is simply the correlation coefficient calculated from rank in list, which allows for nonlinear correlation.) Thus simple indices of transit time (whole-kidney peak time and R20/3) correlated as well with the observed pathology as did more complicated methods that required deconvolution, factor analysis, or selection of a cortical ROI. (orig./MG)

  13. POF strain sensor using phase measurement techniques

    Science.gov (United States)

    Poisel, H.

    2008-03-01

    Polymer optical fiber (POF) elongation sensors have been proposed e.g. by Doering as a low-cost alternative to FBG (single mode Fiber Bragg Gratings) sensors targeting the lower sensitivity range. A recently recovered detection system known from laser distance meters turned out to be very sensitive while staying simple and thus offering low cost potential. The approach is based on measuring the phase shift of a (e.g. sinusoidally) modulated light signal guided in a POF under different tensions resulting in different transit times and thus different phase shifts.

  14. Remote measurement of corrosion using ultrasonic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, K.M.; Porter, A.M.

    1995-02-01

    Supercritical water oxidation (SCWO) technology has the potential of meeting the US Department of Energy`s treatment requirements for mixed radioactive waste. A major technical constraint of the SCWO process is corrosion. Safe operation of a pilot plant requires monitoring of the corrosion rate of the materials of construction. A method is needed for measurement of the corrosion rate taking place during operation. One approach is to directly measure the change in wall thickness or growth of oxide layer at critical points in the SCWO process. In FY-93, a brief survey of the industry was performed to evaluate nondestructive evaluation (NDE) methods for remote corrosion monitoring in supercritical vessels. As a result of this survey, it was determined that ultrasonic testing (UT) methods would be the most cost-effective and suitable method of achieving this. Therefore, the objective for FY-94 was to prove the feasibility of using UT to monitor corrosion of supercritical vessels remotely during operation without removal of the insulation.

  15. Tear film measurement by optical reflectometry technique.

    Science.gov (United States)

    Lu, Hui; Wang, Michael R; Wang, Jianhua; Shen, Meixiao

    2014-02-01

    Evaluation of tear film is performed by an optical reflectometer system with alignment guided by a galvanometer scanner. The reflectometer system utilizes optical fibers to deliver illumination light to the tear film and collect the film reflectance as a function of wavelength. Film thickness is determined by best fitting the reflectance-wavelength curve. The spectral reflectance acquisition time is 15 ms, fast enough for detecting film thickness changes. Fast beam alignment of 1 s is achieved by the galvanometer scanner. The reflectometer was first used to evaluate artificial tear film on a model eye with and without a contact lens. The film thickness and thinning rate have been successfully quantified with the minimum measured thickness of about 0.3 μm. Tear films in human eyes, with and without a contact lens, have also been evaluated. A high-contrast spectral reflectance signal from the precontact lens tear film is clearly observed, and the thinning dynamics have been easily recorded from 3.69 to 1.31 μm with lipid layer thickness variation in the range of 41 to 67 nm. The accuracy of the measurement is better than ±0.58% of the film thickness at an estimated tear film refractive index error of ±0.001. The fiber-based reflectometer system is compact and easy to handle.

  16. Techniques for transparent lattice measurement and correction

    Science.gov (United States)

    Cheng, Weixing; Li, Yongjun; Ha, Kiman

    2017-07-01

    A novel method has been successfully demonstrated at NSLS-II to characterize the lattice parameters with gated BPM turn-by-turn (TbT) capability. This method can be used at high current operation. Conventional lattice characterization and tuning are carried out at low current in dedicated machine studies which include beam-based measurement/correction of orbit, tune, dispersion, beta-beat, phase advance, coupling etc. At the NSLS-II storage ring, we observed lattice drifting during beam accumulation in user operation. Coupling and lifetime change while insertion device (ID) gaps are moved. With the new method, dynamical lattice correction is possible to achieve reliable and productive operations. A bunch-by-bunch feedback system excites a small fraction (∼1%) of bunches and gated BPMs are aligned to see those bunch motions. The gated TbT position data are used to characterize the lattice hence correction can be applied. As there are ∼1% of total charges disturbed for a short period of time (several ms), this method is transparent to general user operation. We demonstrated the effectiveness of these tools during high current user operation.

  17. Acoustic measuring techniques for suspended sediment

    Science.gov (United States)

    Gruber, P.; Felix, D.; Storti, G.; Lattuada, M.; Fleckenstein, P.; Deschwanden, F.

    2016-11-01

    Acoustic signals can be used in various ways for suspended sediment monitoring. One possibility which lends itself particularly well in the context of hydropower plants (HPPs), is to use installations for acoustic discharge measurement (ADM). Such installations already exist at waterways of many HPPs. Similar to certain turbidimeters, the attenuation of the forward scattered signal travelling through the water-sediment mixture is correlated with suspended sediment concentration (SSC). This correlation can be based on reference SSCs, e.g. from gravimetric analyses of bottle samples. Without the need of additional sensors and practically maintenance-free, this method is used successfully in the HPP Fieschertal to warn the HPP operator of high SSC to prevent excessive turbine abrasion. Acoustic methods and systems that allow for estimating both SSC and particle size distribution (PSD) are under development. The simultaneous determination of SSC and PSD is not possible using a single frequency. Therefore, multi-frequency approaches are investigated for generally scattered signals. When backscattered signals are used, a stronger frequency dependency can be exploited. However, the reliable simultaneous determination of particle size (and distribution) and concentration is still a major challenge due to a low signal-to-noise ratio and an ill- posed problem of estimating concentration and size from recorded signals. The optimal setup configuration (angles, frequencies) for such a system is not unique and further investigations are recommended.

  18. Ground-based intercomparison of two isoprene measurement techniques

    Directory of Open Access Journals (Sweden)

    E. Leibrock

    2003-01-01

    Full Text Available An informal intercomparison of two isoprene (C5H8 measurement techniques was carried out during Fall of 1998 at a field site located approximately 3 km west of Boulder, Colorado, USA. A new chemical ionization mass spectrometric technique (CIMS was compared to a well-established gas chromatographic technique (GC. The CIMS technique utilized benzene cation chemistry to ionize isoprene. The isoprene levels measured by the CIMS were often larger than those obtained with the GC. The results indicate that the CIMS technique suffered from an anthropogenic interference associated with air masses from the Denver, CO metropolitan area as well as an additional interference occurring in clean conditions. However, the CIMS technique is also demonstrated to be sensitive and fast. Especially after introduction of a tandem mass spectrometric technique, it is therefore a candidate for isoprene measurements in remote environments near isoprene sources.

  19. Comparing techniques for measuring corticosterone in tadpoles

    Institute of Scientific and Technical Information of China (English)

    Pablo BURRACO; Rosa ARRIBAS; Saurabh S KULKARNI; Daniel R BUCHHOLZ; Ivan GOMEZ-MESTRE

    2015-01-01

    Glucocorticoids play a key role in mediating stress responses in vertebrates. Corticosterone (CORT) is the main glu-cocorticoid produced in amphibians, birds, and reptiles, and regulates several metabolic functions. The most common methods for quantifying CORT are competitive binding immunoassays: radioimmunoassay (RIA) and enzyme immunoassay (EIA). RIA has been broadly used since the 1980’s but it requires radioactivity. Commercial EIA kits permit quantifying hormone levels without radioactivity although the requirement for a larger sample volume may be a strong limitation for measurements involving larval amphibians. Here we usedXenopus laevis tadpoles to compare the performance of three commonly used procedures for determination of CORT: RIA on a chloroform extract of whole-body homogenate, EIA on plasma, and EIA on supernatant of whole-body homogenate. We treated tadpoles with exogenous CORT at 0, 25, 50, and 100 nM. RIA could distinguish between 0 and 25 nM, and EIA on plasma between 0 and 50 nM, whereas whole-body homogenate EIA only detected significant differences between 0 and 100 nM. Each procedure presents advantages and disadvantages regarding sensitivity, the use of radioactivity, sample size, handling time, and economic cost. RIA is preferred when studying small-bodied animals from which blood samples cannot be obtained. When CORT level differences are intermediate and blood sampling is possible, EIA on plasma is a good non-radioactive alternative. EIA on whole-body homogenates may be useful to assess qualitative changes in CORT levels when considerable differences are expected. Finally, we discuss our findings in the context of previous studies on CORT in amphibians [Current Zoology 61 (5): 835–845, 2015].

  20. The Sine Method: An Alternative Height Measurement Technique

    Science.gov (United States)

    Don C. Bragg; Lee E. Frelich; Robert T. Leverett; Will Blozan; Dale J. Luthringer

    2011-01-01

    Height is one of the most important dimensions of trees, but few observers are fully aware of the consequences of the misapplication of conventional height measurement techniques. A new approach, the sine method, can improve height measurement by being less sensitive to the requirements of conventional techniques (similar triangles and the tangent method). We studied...

  1. Particle fluence measurements by activation technique for radiation damage studies

    CERN Document Server

    León-Florián, E; Furetta, C; Leroy, Claude

    1995-01-01

    High-level radiation environment can produce radiation damage in detectors and their associate electronic components. The establishment of a correlation between damage, irradiation level and absorbed dose requires a precise measurement of the fluence of particles causing the damage. The activation technique is frequently used for performing particle fluence measurements. A review of this technique is presented.

  2. Equipment for measuring radiation. Part 3. Technique of measuring radiation

    Energy Technology Data Exchange (ETDEWEB)

    Radwanowski, L.J.

    1979-01-01

    Difficulties are noted in measuring the effects of radiation because of the excessively low energy of the measured fields. In nature there are different magnetic-dynamic and magnetic-hydrodynamic generators which are sources of very low intensity which changes in time. The equipment of measurements is examined in the example of one of the generators, underground water current. The apparatus is described in detail for measuring the intensity of the electromagnetic SHF field. Under the underground water currents a change is observed in the intensity of the electromagnetic field. The possibilities are also examined of direct measurement of ultrasonic elastic fluctuations caused by the underground current, as well as the possibility of recording other physical fields (spontaneous polarization, soil temperature). A study was made of the effect of the underground water current on the occurrence of physical, chemical and biological processes: photochemical reactions, reactions of metal oxidation, Golomb effect (change in the rate of sedimentation of argillaceous particles in water under the influence of a biofield), change in air humidity and soil water content, change in intensity of the magnetic field, Hall effect, change in luminescence of certain organisms or the luminophore released by them. Basic plans are presented of certain measurement and recording devices.

  3. MPPT Technique Based on Current and Temperature Measurements

    Directory of Open Access Journals (Sweden)

    Eduardo Moreira Vicente

    2015-01-01

    Full Text Available This paper presents a new maximum power point tracking (MPPT method based on the measurement of temperature and short-circuit current, in a simple and efficient approach. These measurements, which can precisely define the maximum power point (MPP, have not been used together in other existing techniques. The temperature is measured with a low cost sensor and the solar irradiance is estimated through the relationship of the measured short-circuit current and its reference. Fast tracking speed and stable steady-state operation are advantages of this technique, which presents higher performance when compared to other well-known techniques.

  4. Opto-thermal in-vivo skin hydration measurements - a comparison study of different measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, P; Singh, H; Imhof, R E [Faculty of ESBE, London South Bank University, 103 Borough Road, London SE1 0AA (United Kingdom); Ciortea, L I; Berg, E P [Biox Systems Ltd, 103 Borough Road, London SE1 0AA (United Kingdom); Cui, Y, E-mail: xiaop@lsbu.ac.u [Sunrise Systems Limited, Flint Bridge Business Centre, Ely Road, Waterbeach, Cambridge CB5 9QZ (United Kingdom)

    2010-03-01

    We compared five different skin hydration measurement techniques, namely OTTER, Fingerprint sensors, Corneometer, Nova, and Moisture Checker, in order to understand the correlations between different skin hydration measurement techniques and to understand the repeatability of each technique. The measurements are performed on different in-vivo skin sites from different volunteers and at different hydration levels. The repeatability of different techniques is achieved by measuring the same skin site repeatedly. The correlations between different skin hydration measurement techniques are achieved by plotting results from different techniques against each other. The different skin hydration levels are achieved through the recovery period after a skin immersive hydration.

  5. Companding technique for high dynamic range measurements using Gafchromic films

    Energy Technology Data Exchange (ETDEWEB)

    Van den Heuvel, Frank; Crijns, Wouter; Defraene, Gilles [Department of Experimental Radiotherapy, Catholic University of Leuven, Leuven, Belgium B-3000 (Belgium)

    2011-12-15

    Purpose: To introduce a methodology to perform dose measurements using Gafchromic films which can span several decades of dose levels. Methods: The technique is based on a rescaling approach using different films irradiated at different dose levels. This is combined with a registration protocol correcting positioning and scaling factors for each film. The methodology is validated using TLD's for out-of-field doses. Furthermore, two examples are provided using the technique to characterize small sized radiosurgery cones and compared with measurements made with a pinpoint chamber. Results: Excellent agreement with TLD, planning systems and measurement was found. The superior resolution of the film technique was apparent. Conclusions: The authors have introduced a new technique allowing users to quantify very low doses in conjunction with commissioning measurements. The use of film also provides 2D information on beam characteristics in high resolution measurements.

  6. Technique for Measuring Body Circumferences and Skinfold Thicknesses.

    Science.gov (United States)

    1984-08-01

    of the tape measure. Technique For ease and accuracy of measurement, male subjects ( persons being measured) should wear swim suits or shorts and female...are now touching the second costo -sternal joint (Figure 3a). There is usually a slight bulge or prominence on the sternum at this level. This

  7. Digital technique for the simultaneous measurement of velocity and temperature.

    Science.gov (United States)

    Keffer, J F; Budny, R S; Kawall, J G

    1978-09-01

    A computer-oriented, hot-wire anemometer technique for the simultaneous measurement of velocity and temperature in heated turbulent flows is described. This technique involves conversion of analogue anemometer voltage signals into digital forms and processing of these latter on a digital computer, in accordance with the anemometer response equations, to obtain instantaneous temperature and velocity. The technique was tested with a heated plane jet and found to be satisfactory.

  8. High Statistics Analysis using Anisotropic Clover Lattices: (IV) The Volume Dependence of the Light Hadron Masses

    Energy Technology Data Exchange (ETDEWEB)

    Beane, S R; Detmold, W; Lin, H W; Luu, T C; Orginos, K; Parreno, A; Savage, M J; Torok, A; Walker-Loud, A

    2011-07-01

    The volume dependence of the octet baryon masses and relations among them are explored with Lattice QCD. Calculations are performed with nf = 2 + 1 clover fermion discretization in four lattice volumes, with spatial extent L ? 2.0, 2.5, 3.0 and 4.0 fm, with an anisotropic lattice spacing of b_s ? 0.123 fm in the spatial direction, and b_t = b_s/3.5 in the time direction, and at a pion mass of m_\\pi ? 390 MeV. The typical precision of the ground-state baryon mass determination is volume dependence of the masses, the Gell-Mann Okubo mass-relation, and of other mass combinations. A comparison with the predictions of heavy baryon chiral perturbation theory is performed in both the SU(2)L ? SU(2)R and SU(3)L ? SU(3)R expansions. Predictions of the three-flavor expansion for the hadron masses are found to describe the observed volume dependences reasonably well. Further, the ?N? axial coupling constant is extracted from the volume dependence of the nucleon mass in the two-flavor expansion, with only small modifications in the three-flavor expansion from the inclusion of kaons and eta's. At a given value of m?L, the finite-volume contributions to the nucleon mass are predicted to be significantly smaller at m_\\pi ? 140 MeV than at m_\\pi ? 390 MeV due to a coefficient that scales as ? m_\\pi^3. This is relevant for the design of future ensembles of lattice gauge-field configurations. Finally, the volume dependence of the pion and kaon masses are analyzed with two-flavor and three-flavor chiral perturbation theory.

  9. A Survey of Advanced Microwave Frequency Measurement Techniques

    Directory of Open Access Journals (Sweden)

    Anand Swaroop Khare

    2012-06-01

    Full Text Available Microwaves are radio waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. The science of photonics includes the generation, emission, modulation, signal processing, switching, transmission, amplification, detection and sensing of light. Microwave photonics has been introduced for achieving ultra broadband signal processing. Instantaneous Frequency Measurement (IFM receivers play an important role in electronic warfare. Technologies used for signal processing, include conventional direct Radio Frequency (RF techniques, digital techniques, intermediate frequency (IF techniques and photonic techniques. Direct RF techniques suffer an increased loss, high dispersion, and unwanted radiation problems in high frequencies. The systems that use traditional RF techniques can be bulky and often lack the agility required to perform advanced signal processing in rapidly changing environments. In this paper we discussed a survey of Microwave Frequency Measurement Techniques. The microwaves techniques are categorized based upon different approaches. This paper provides the major advancement in the Microwave Frequency MeasurementTechniques research; using these approaches the features and categories in the surveyed existing work.

  10. A New Technique for Measuring the Heat Loss Coefficient

    DEFF Research Database (Denmark)

    Svendsen, Sv Aa Højgaard; Rose, Jørgen

    1996-01-01

    To measure the effect of linear cold bridges in building envelope constructions the guarded hot box technique is used. A new method based on a guarded hot plate technique has been proposed and investigated with respect to errors. The results are promising and further development of the method is ...

  11. Measurement techniques for radiological characterization of contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    Loos, M.

    1996-09-18

    Once the decision is taken to characterize a contaminated site, appropriate measurement techniques must be selected. The choice will depend on the available information, on the nature and extent of the contamination, as well as on available resources (staff and budget). Some techniques are described on the basis of examples of characterization projects (e.g. Olen area in Belgium).

  12. Effects of equipment and technique on peak flow measurements

    Directory of Open Access Journals (Sweden)

    O'Driscoll B Ronan

    2006-06-01

    Full Text Available Abstract Background Different lung function equipment and different respiratory manoeuvres may produce different Peak Expiratory Flow (PEF results. Although the PEF is the most common lung function test, there have been few studies of these effects and no previous study has evaluated both factors in a single group of patients. Methods We studied 36 subjects (PEF range 80–570 l/min. All patients recorded PEF measurements using a short rapid expiration following maximal inspiration (PEF technique or a forced maximal expiration to residual volume (FVC technique. Measurements were made using a Wright's peak flow meter, a turbine spirometer and a Fleisch pneumotachograph spirometer. Results The mean PEF was 8.7% higher when the PEF technique was used (compared with FVC technique, p Conclusion Peak flow measurements are affected by the instruction given and by the device and Peak Flow scale used. Patient management decisions should not be based on PEF measurement made on different instruments.

  13. Measuring elastic constants using non-contact ultrasonic techniques

    Science.gov (United States)

    Edwards, R. S.; Perry, R.; Cleanthous, D.; Backhouse, D. J.; Moore, I. J.; Clough, A. R.; Stone, D. I.

    2012-05-01

    The use of ultrasound for measuring elastic constants and phase transitions is well established. Standard measurements use piezoelectric transducers requiring couplant and contact with the sample. Recently, non-destructive testing (NDT) has seen an increase in the use of non-contact ultrasonic techniques, for example electromagnetic acoustic transducers (EMATs) and laser ultrasound, due to their many benefits. For measurements of single crystals over a range of temperatures non-contact techniques could also bring many benefits. These techniques do not require couplant, and hence do not suffer from breaking of the bond between transducer and sample during thermal cycling, and will potentially lead to a simpler and more adaptable measurement system with lower risk of sample damage. We present recent work adapting EMAT advances from NDT to measurements of single crystals at cryogenic temperatures and illustrate this with measurements of magnetic phase transitions in Gd64Sc36 using both contact and non-contact transducers. We discuss the measurement techniques implemented to overcome noise problems, and a digital pulse-echo-overlap technique, using data analysis in the frequency domain to measure the velocity.

  14. Error reduction techniques for measuring long synchrotron mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Irick, S.

    1998-07-01

    Many instruments and techniques are used for measuring long mirror surfaces. A Fizeau interferometer may be used to measure mirrors much longer than the interferometer aperture size by using grazing incidence at the mirror surface and analyzing the light reflected from a flat end mirror. Advantages of this technique are data acquisition speed and use of a common instrument. Disadvantages are reduced sampling interval, uncertainty of tangential position, and sagittal/tangential aspect ratio other than unity. Also, deep aspheric surfaces cannot be measured on a Fizeau interferometer without a specially made fringe nulling holographic plate. Other scanning instruments have been developed for measuring height, slope, or curvature profiles of the surface, but lack accuracy for very long scans required for X-ray synchrotron mirrors. The Long Trace Profiler (LTP) was developed specifically for long x-ray mirror measurement, and still outperforms other instruments, especially for aspheres. Thus, this paper focuses on error reduction techniques for the LTP.

  15. An ultrasonic technique for measuring stress in fasteners

    Science.gov (United States)

    Stevens, K. J.; Day, P.; Byron, D.

    1999-12-01

    High temperature bolting alloys are extensively used in the thermal power generation industry as for example, reheat ESV and Governor valve studs. Remnant life assessment methodologies and plant maintenance procedures require the monitoring of the operational stress levels in these fasteners. Some conventional ultrasonic techniques require longitudinal wave measurements to be undertaken when the nut on the bolt is loosened and then re-tightened. Other techniques use a combination of shear waves and longitudinal waves. In this paper, the problems and pitfalls associated with various ultrasonic techniques for measuring stress in bolts, is discussed. An ultrasonic technique developed for measuring the stress in Durehete 1055 bolts is presented. Material from a textured rolled bar has been used as a test bed in the development work. The technique uses shear wave birefringence and compression waves at several frequencies to measure texture, fastener length and the average stress. The technique was developed by making ultrasonic measurements on bolts tensioned in universal testing machines and a hydraulic nut. The ultrasonic measurements of residual stress have been checked against strain gauge measurements. The Durehete bolts have a hollow cylinder geometry of restricted dimensions, which significantly alters compression and shear wave velocities from bulk values and introduces hoop stresses which can be measured by rotating the polarization of the shear wave probe. Modelling of the experimental results has been undertaken using theories for the elastic wave propagation through waveguides. The dispersion equations allow the velocity and length of the fastener to be measured ultrasonically in some situations where the length of the fastener can not be measured directly with a vernier caliper or micrometer and/or where it is undesirable to loosen nuts to take calibration readings of the shear and compression wave velocities.

  16. High impulse voltage and current measurement techniques fundamentals, measuring instruments, measuring methods

    CERN Document Server

    Schon, Klaus

    2013-01-01

    Equipment to be installed in electric power-transmission and distribution systems must pass acceptance tests with standardized high-voltage or high-current test impulses which simulate the stress on the insulation caused by external lightning discharges and switching operations in the grid. High impulse voltages and currents are also used in many other fields of science and engineering for various applications. Therefore, precise impulse-measurement techniques are necessary, either to prevent an over- or understressing of the insulation or to guarantee the effectiveness and quality of the application. The book deals with: principal generator circuits for generating high-voltage and high-current impulses measuring systems and their calibration according to IEC 60060 and IEC 62475 methods of estimating uncertainties of measurement mathematical and experimental basis for characterizing the transfer behavior of spatially extended systems used for measuring fast transients. This book is intended for engineers and ...

  17. The Evolving Field of Wound Measurement Techniques: A Literature Review.

    Science.gov (United States)

    Khoo, Rachel; Jansen, Shirley

    2016-06-01

    Wound healing is a complex and multifactorial process that requires the involvement of a multidisciplinary approach. Methods of wound measurement have been developed and continually refined with the purpose of ensuring precision in wound measurement and documentation as the primary indicator of healing. This review aims to ascertain the efficacies of current wound area measurement techniques, and to highlight any perceived gaps in the literature so as to develop suggestions for future studies and practice. Med- line, PubMed, CliniKey, and CINAHL were searched using the terms "wound/ulcer measurement techniques," "wound assessment," "digi- tal planimetry," and "structured light." Articles between 2000 and 2014 were selected, and secondary searches were carried out by exam- ining the references of relevant articles. Only papers written in English were included. A universal, standardized method of wound as- sessment has not been established or proposed. At present, techniques range from the simple to the more complex - most of which have char- acteristics that allow for applicability in both rural and urban settings. Techniques covered are: ruler measurements, acetate tracings/contact planimetry, digital planimetry, and structured light devices. Conclu- sion. In reviewing the literature, the precision and reliability of digital planimetry over the more conventional methods of ruler measurements and acetate tracings are consistently demonstrated. The advent and utility of the laser or structured light approach, however, is promising, has only been analyzed by a few, and opens up the scope for further evaluation of this technique.

  18. Blower-door techniques for measuring interzonal leakage

    Energy Technology Data Exchange (ETDEWEB)

    Hult, Erin L.; Sherman, Max H.; Walker, Iain

    2013-01-01

    Abstract The standard blower door test methods, such as ASTM E779, describe how to use a single blower door to determine the total leakage of a single-zone structure such as a detached single-family home. There are no standard test methods for measuring interzonal leakage in a two-zone or multi-zone building envelope such as might be encountered in with an attached garage or in a multifamily building. Some practitioners have been using techniques that involve making multiple measurements with a single blower door as well as combined measurements using multiple blower doors. Even for just two zones there are dozens of combinations of one-door and two-door test protocols that could conceivably be used to determine the interzonal air tightness. We examined many of these two-zone configurations using both simulation and measured data to estimate the accuracy and precision of each technique for realistic measurement scenarios. We also considered the impact of taking measurements at a single pressure versus over multiple pressures. We compared the various techniques and evaluated them for specific uses. Some techniques work better in one leakage regime; some are more sensitive to wind and other noise; some are more suited to determining only a subset of the leakage values. This paper makes recommendations on which techniques to use or not use for various cases and provides data that could be used to develop future test methods.

  19. An intensity-monitoring technique for measuring ellipsometric transients

    NARCIS (Netherlands)

    Droog, J.M.M.; Bootsma, G.A.

    1979-01-01

    Intensity-monitoring techniques make possible the measurement of rapid changes in the ellipsometric parameters. Methods used hitherto have been suitable for measuring slight changes only and require prior knowledge of the Δ and Ψ values for the initial surface. It is shown that larger changes can al

  20. Design techniques for large scale linear measurement systems

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1979-03-01

    Techniques to design measurement schemes for systems modeled by large scale linear time invariant systems, i.e., physical systems modeled by a large number (> 5) of ordinary differential equations, are described. The techniques are based on transforming the physical system model to a coordinate system facilitating the design and then transforming back to the original coordinates. An example of a three-stage, four-species, extraction column used in the reprocessing of spent nuclear fuel elements is presented. The basic ideas are briefly discussed in the case of noisy measurements. An example using a plutonium nitrate storage vessel (reprocessing) with measurement uncertainty is also presented.

  1. Volume Measurement in Solid Objects Using Artificial Vision Technique

    Science.gov (United States)

    Cordova-Fraga, T.; Martinez-Espinosa, J. C.; Bernal, J.; Huerta-Franco, R.; Sosa-Aquino, M.; Vargas-Luna, M.

    2004-09-01

    A simple system using artificial vision technique for measuring the volume of solid objects is described. The system is based on the acquisition of an image sequence of the object while it is rotating on an automated mechanism controlled by a PC. Volumes of different objects such as a sphere, a cylinder and also a carrot were measured. The proposed algorithm was developed in environment LabView 6.1. This technique can be very useful when it is applied to measure the human body for evaluating its body composition.

  2. Optical skin friction measurement technique in hypersonic wind tunnel

    Science.gov (United States)

    Chen, Xing; Yao, Dapeng; Wen, Shuai; Pan, Junjie

    2016-10-01

    Shear-sensitive liquid-crystal coatings (SSLCCs) have an optical characteristic that they are sensitive to the applied shear stress. Based on this, a novel technique is developed to measure the applied shear stress of the model surface regarding both its magnitude and direction in hypersonic flow. The system of optical skin friction measurement are built in China Academy of Aerospace Aerodynamics (CAAA). A series of experiments of hypersonic vehicle is performed in wind tunnel of CAAA. Global skin friction distribution of the model which shows complicated flow structures is discussed, and a brief mechanism analysis and an evaluation on optical measurement technique have been made.

  3. Measurement of thermophysical properties by a pulse-heating technique

    Institute of Scientific and Technical Information of China (English)

    Peng Xiao; Jingmin Dai; Qingwei Wang

    2007-01-01

    A technique is described for the dynamic measurement of selected thermophysical properties of electrically conducting solids in the temperature range from 1100 K to the melting point. Based on rapid resistive self-heating of the specimen from room temperature to any desired high temperature in several seconds by the passage of an electical current pulse through it, this technique measures the pertinent quantities such as current, voltage, randiance temperature, with sub-millisecond time resolution. The pulse-heating technique is applied to strip specimens. The radiance temperature is measured by high-speed pyrometry,normal spectral emissivity of the strips is measured by integrating sphere reflectometry. The normal spectral emissivity results are used to compute the true temperature of the specimens. The heat capacity,electrical resistivity, total hemispherical emissivity are evaluated in the temperature range from 1100 K to the melting point.

  4. Videogrammetric Model Deformation Measurement Technique for Wind Tunnel Applications

    Science.gov (United States)

    Barrows, Danny A.

    2006-01-01

    Videogrammetric measurement technique developments at NASA Langley were driven largely by the need to quantify model deformation at the National Transonic Facility (NTF). This paper summarizes recent wind tunnel applications and issues at the NTF and other NASA Langley facilities including the Transonic Dynamics Tunnel, 31-Inch Mach 10 Tunnel, 8-Ft high Temperature Tunnel, and the 20-Ft Vertical Spin Tunnel. In addition, several adaptations of wind tunnel techniques to non-wind tunnel applications are summarized. These applications include wing deformation measurements on vehicles in flight, determining aerodynamic loads based on optical elastic deformation measurements, measurements on ultra-lightweight and inflatable space structures, and the use of an object-to-image plane scaling technique to support NASA s Space Exploration program.

  5. A novel in-situ measuring technique for aspheric surface

    Science.gov (United States)

    Zhang, Chuan; Wang, Ping; Chen, Yaolong

    2011-11-01

    In this paper, a novel in-situ surface measuring technique for optical elements with aspheric surface is presented. It is a contact type probe, and can be used for measuring ground surfaces. The theory of this technique develops from coordinate measuring machine (CMM), and the measurement accuracy of this technique is depended on the accuracy of computer numerical controlled (CNC). By installing a special equipment with high accuracy measuring head in main spindle of CNC machine, and moving the probe along the path which is described by a mathematical aspheric expression precisely, we could get relative errors of sag height of any position in this path. With this technique, the repeat positioning error caused by traditional off-line measurement will be avoided. The author also has finished a special software with VC++ 6.0. With this software, the form error of ground work piece could be corrected rapidly. This software can calculate and handle the arrangement automatically with all parameters which are required to input in operation interface. In the correction stage, the software can analyze and process error data and generate a new NC program with corrected data for next grinding stage. After 2 or 3 times measuring and correction, the surface shape error of the aspheric optical element will be less than 1μm. The finished work piece has a very good surface finish and can be polished with high quality.

  6. Assessing the measurement of airway resistance by the interrupter technique.

    Science.gov (United States)

    Zuriarrain Reyna, Yolanda; López Neyra, Alejandro; Sanz Santiago, Verónica; Almería Gil, Esmeralda; Villa Asensi, José Ramón

    2013-12-01

    Pulmonary function tests allow an objective assessment of the degree of bronchial obstruction in collaborative subjects. The measurement of airway resistance using passive methods is very helpful in non-collaborative subjects. The objective of this study was to assess the applicability of measuring airway resistance by the interrupter technique (Rint) in pediatric subjects, determining its reproducibility, reliability and accuracy versus other techniques to measure airway resistance. Cross-sectional study in healthy children and in children with an obstructive airway disease, all aged 2-18 years old. The Rint was measured using a portable device and results were compared to airway resistance measured by oscillometry and plethysmography. The reproducibility of measurements and the infuence of the different outcome measures (use of mask or mouthpiece, cheek support, or nose clip) were assessed. Valid measurements were obtained in 82.6% of 460 children (47.6% younger than 7 years old). Reproducibility was very good (ICC= 0.9412; p measurements obtained at separate time intervals (0.75 ± 0.3 versus 0.74 ± 0.28; p= 0.435). None of the factors indicated before had an effect on the reproducibility of measurements. Resistance values obtained by plethysmography and oscillometry were higher than those obtained using the Rint, with a positive correlation between them. The higher the degree of airway obstruction, the worse the correlation with plethysmography. The Rint measurement is a plausible and reproducible technique, and has an adequate correlation with the resistance measurements obtained using oscillometry or plethysmography, thus making it useful for non-collaborative patients. In patients with airway obstruction, this technique could underestimate resistance, so it would be a hurdle to use it to follow-up subjects with a moderate to severe obstructive disease or in bronchial challenge tests.

  7. Measurement of Thermal Expansion Coefficients with Holographic Technique

    Institute of Scientific and Technical Information of China (English)

    ZhifengZhang

    1995-01-01

    A simplified mathematical model was created for measurement of thermal expansion coefficients of thin sheet materials with holographic technique.Experimental set-ups corresponding to the mathematical model were designed and built for both tests above room temperature and at low temperatures.A fringe control technique was introduced for low temperature measurements to compensate rigid body movement,THin sheet specimens of silicon and aluminum alloy(7075) were tested with the developed technique.The tested results are in good agreement with reported data and thus verify the validity of the developed technique.The Thermal expansion coefficients of the tested materials ranged from 2.5×10-60C-1 to 23.6×10-6oC-1.

  8. Handbook of microwave component measurements with advanced VNA techniques

    CERN Document Server

    Dunsmore, Joel P

    2012-01-01

    This book provides state-of-the-art coverage for making measurements on RF and Microwave Components, both active and passive. A perfect reference for R&D and Test Engineers, with topics ranging from the best practices for basic measurements, to an in-depth analysis of errors, correction methods, and uncertainty analysis, this book provides everything you need to understand microwave measurements. With primary focus on active and passive measurements using a Vector Network Analyzer, these techniques and analysis are equally applicable to measurements made with Spectrum Analyzers or Noise Figure

  9. Measurement of fuel spray vaporisation by laser techniques

    Science.gov (United States)

    Yule, A. J.; Seng, C. A.; Felton, P. G.; Ungut, A.; Chigier, N. A.

    1980-01-01

    Comparison of fuel spray structures in heated and in cold environments is made by using a new laser tomographic technique and laser anemometry. The tomography technique is shown to give accurate and rapid 'point' measurements of droplet sizes and concentrations. Experimental results show acceleration of droplets to the local gas velocity, preferential vaporisation of the smallest droplets and the dispersion of droplets by the turbulence.

  10. Thermal properties measurements in biodiesel oils using photothermal techniques

    Science.gov (United States)

    Castro, M. P. P.; Andrade, A. A.; Franco, R. W. A.; Miranda, P. C. M. L.; Sthel, M.; Vargas, H.; Constantino, R.; Baesso, M. L.

    2005-08-01

    In this Letter, thermal lens and open cell photoacoustic techniques are used to measure the thermal properties of biodiesel oils. The absolute values of the thermal effusivity, thermal diffusivity, thermal conductivity and the temperature coefficient of the refractive index were determined for samples obtained from soy, castor bean, sunflower and turnip. The results suggest that the employed techniques may be useful as complementary methods for biodiesel certification.

  11. Ultrasonic Technique for Density Measurement of Liquids in Extreme Conditions

    Directory of Open Access Journals (Sweden)

    Rymantas Kazys

    2015-08-01

    Full Text Available An ultrasonic technique, invariant to temperature changes, for a density measurement of different liquids under in situ extreme conditions is presented. The influence of geometry and material parameters of the measurement system (transducer, waveguide, matching layer on measurement accuracy and reliability is analyzed theoretically along with experimental results. The proposed method is based on measurement of the amplitude of the ultrasonic wave, reflected from the interface of the solid/liquid medium under investigation. In order to enhance sensitivity, the use of a quarter wavelength acoustic matching layer is proposed. Therefore, the sensitivity of the measurement system increases significantly. Density measurements quite often must be performed in extreme conditions at high temperature (up to 220 °C and high pressure. In this case, metal waveguides between piezoelectric transducer and the measured liquid are used in order to protect the conventional transducer from the influence of high temperature and to avoid depolarization. The presented ultrasonic density measurement technique is suitable for density measurement in different materials, including liquids and polymer melts in extreme conditions. A new calibration algorithm was proposed. The metrological evaluation of the measurement method was performed. The expanded measurement uncertainty Uρ = 7.4 × 10−3 g/cm3 (1%.

  12. Reflectometry techniques for density profile measurements on fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Laviron, C. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Donne, A.J.H. [Associatie Euratom-FOM, Nieuwegein (Netherlands). FOM-Instituut voor Plasmafysica; Manso, M.E. [Instituto Superior Tecnico, Lisbon (Portugal). Lab. de Quimica Organica; Sanchez, J. [EURATOM-CIEMAT for Fusion Association, Madrid (Spain)

    1996-03-01

    Reflectometry applied to the measurement of density profiles on fusion plasmas has been subject to many recent developments. After a brief reminder of the principles of reflectometry, the theoretical accuracy of reflectometry measurements is discussed. The main difficulties limiting the performance, namely the plasma fluctuations and the quality of the transmission lines, are analysed. The different techniques used for reflectometry are then presented. The present status and achievements of actual implementations of these techniques are shown, with an analysis of their respective limitations and merits, as well as foreseen developments. (author). 70 refs.

  13. Infrared Spectroscopy of Explosives Residues: Measurement Techniques and Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Bernacki, Bruce E.

    2015-03-11

    Infrared laser spectroscopy of explosives is a promising technique for standoff and non-contact detection applications. However, the interpretation of spectra obtained in typical standoff measurement configurations presents numerous challenges. Understanding the variability in observed spectra from explosives residues and particles is crucial for design and implementation of detection algorithms with high detection confidence and low false alarm probability. We discuss a series of infrared spectroscopic techniques applied toward measuring and interpreting the reflectance spectra obtained from explosives particles and residues. These techniques utilize the high spectral radiance, broad tuning range, rapid wavelength tuning, high scan reproducibility, and low noise of an external cavity quantum cascade laser (ECQCL) system developed at Pacific Northwest National Laboratory. The ECQCL source permits measurements in configurations which would be either impractical or overly time-consuming with broadband, incoherent infrared sources, and enables a combination of rapid measurement speed and high detection sensitivity. The spectroscopic methods employed include standoff hyperspectral reflectance imaging, quantitative measurements of diffuse reflectance spectra, reflection-absorption infrared spectroscopy, microscopic imaging and spectroscopy, and nano-scale imaging and spectroscopy. Measurements of explosives particles and residues reveal important factors affecting observed reflectance spectra, including measurement geometry, substrate on which the explosives are deposited, and morphological effects such as particle shape, size, orientation, and crystal structure.

  14. Swept frequency technique for dispersion measurement of microstrip lines

    Science.gov (United States)

    Lee, Richard Q.

    1987-01-01

    Microstrip lines used in microwave integrated circuits are dispersive. Because a microstrip line is an open structure, the dispersion can not be derived with pure TEM, TE, or TM mode analysis. Dispersion analysis has commonly been done using a spectral domain approach, and dispersion measurement has been made with high Q microstrip ring resonators. Since the dispersion of a microstrip line is fully characterized by the frequency dependent phase velocity of the line, dispersion measurement of microstrip lines requires the measurement of the line wavelength as a function of frequency. In this paper, a swept frequency technique for dispersion measurement is described.

  15. Measurement of moisture in materials. Fundamentals - measuring techniques - applications - standards; Materialfeuchtemessung. Grundlagen - Messverfahren - Applikationen - Normen

    Energy Technology Data Exchange (ETDEWEB)

    Kupfer, K.; Knoechel, R.; Menke, F.; Krus, M.; Koch, W.; Brokmann, T.; Stopp, H.; Kahle, M.; Bachmann, C.; Goeller, A.; Leschnik, W.; Hauenschild, C.; Herrmann, R.; Klein, A.; Neue, J.; Haeupl, P.; Eggers, R.; Sikora, J.; Fechner, H.; Boltze, T.; Hinz, T.; Vogt, O.

    1997-12-31

    The book deals with fundamentals of moisture measurement, the physical properties of water/solids mixtures, but also reference methods such as the drying closet method, microwave drying, infrared drying, and Karl-Fischer titration. Competent experts present current methods of conductimetry, capacitive measuring techniques, microwave measuring techniques, nuclear resonance measuring techniques, nuclear radiometry techniques, infrared measuring techniques, thermal conductivity measurement techniques and hygrometric techniques. Apart from the physical bases, the authors look at factors of interference, measuring systems, as well as applications. Microwave measuring techniques offer the advantages of non-destructive measurement, independence of salt content, and density compensation. (orig./MM) 260 figs., 19 tabs., 386 refs. [Deutsch] Das Buch behandelt Grundlagen der Feuchtemessung, physikalische Eigenschaften von Wasser-Feststoff-Gemischen, aber auch Referenzverfahren, wie Trockenschrankverfahren, Mikrowellentrocknung, Infrarottrocknung und Karl-Fischer-Titration. Von kompetenten Fachleuten werden die in der Praxis ueblichen Leitfaehigkeitsmessverfahren, kapazitiven Messverfahren, Mikrowellenmessverfahren, Kernresonanzverfahren, Kernstrahlungsverfahren, Infrarot-Messverfahren, Waermeleitfaehigkeitsmessverfahren und hydrometrischen Messverfahren vorgestellt. Es werden sowohl physikalische Grundlagen, Stoergroessen, Messsysteme, aber auch Applikationen behandelt. Mikrowellenmessverfahren bieten Vorteile einer zerstoerungsfreien Messung, der Unabhaengigkeit vom Salzgehalt und Moeglichkeiten der Dichtekompensation. (orig./MM)

  16. Updates on measurements and modeling techniques for expendable countermeasures

    Science.gov (United States)

    Gignilliat, Robert; Tepfer, Kathleen; Wilson, Rebekah F.; Taczak, Thomas M.

    2016-10-01

    The potential threat of recently-advertised anti-ship missiles has instigated research at the United States (US) Naval Research Laboratory (NRL) into the improvement of measurement techniques for visual band countermeasures. The goal of measurements is the collection of radiometric imagery for use in the building and validation of digital models of expendable countermeasures. This paper will present an overview of measurement requirements unique to the visual band and differences between visual band and infrared (IR) band measurements. A review of the metrics used to characterize signatures in the visible band will be presented and contrasted to those commonly used in IR band measurements. For example, the visual band measurements require higher fidelity characterization of the background, including improved high-transmittance measurements and better characterization of solar conditions to correlate results more closely with changes in the environment. The range of relevant engagement angles has also been expanded to include higher altitude measurements of targets and countermeasures. In addition to the discussion of measurement techniques, a top-level qualitative summary of modeling approaches will be presented. No quantitative results or data will be presented.

  17. Advanced spherical near-field antenna measurement techniques

    DEFF Research Database (Denmark)

    Nielsen, Jeppe Majlund; Pivnenko, Sergey; Breinbjerg, Olav

    2011-01-01

    The DTU-ESA facility has since the 1980es provided highly accurate antenna radiation pattern measurements and gain calibration by use of the probe corrected spherical nearfield technique, both for ESA (the European Space Agency) and other customers and continues to do so. Recent years activities ...

  18. Companding technique for high dynamic range measurements using gafchromic films

    CERN Document Server

    Heuvel, Frank Van den; Defraene, Gilles

    2011-01-01

    We propose a methodology to perform dose measurements using gafchromic films which can span several decades of dose levels. The technique is based on a rescaling approach using different films irradiated at different dose levels. This is combined with a registration protocol correcting positioning and scaling factors for each film.

  19. Doppler lidar wind measurement with the edge technique

    Science.gov (United States)

    Korb, C. Laurence; Gentry, Bruce M.

    1992-01-01

    The edge technique is a new and powerful method for measuring small frequency shifts. Range resolved lidar measurements of winds can be made with high accuracy and high vertical resolution using the edge technique to measure the Doppler shift of an atmospheric backscattered signal from a pulsed laser. The edge technique can be used at near-infrared or visible wavelengths using well developed solid state lasers and detectors with various edge filters. In the edge technique, the laser frequency is located on the steep slope of the spectral response function of a high resolution optical filter. Due to the steep slope of the edge, very small frequency shifts cause large changes in measured signal. The frequency of the outgoing laser pulse is determined by measuring its location on the edge of the filter. This is accomplished by sending a small portion of the beam to the edge detection setup where the incoming light is split into two channels - an edge filter and an energy monitor channel. The energy monitor signal is used to normalize the edge filter signal for magnitude. The laser return backscattered from the atmosphere is collected by a telescope and directed through the edge detection setup to determine its frequency (location on the edge) in a similar manner for each range element. The Doppler shift, and thus the wind, is determined from a differential measurement of the frequency of the outgoing laser pulse and the frequency of the laser return backscattered from the atmosphere. We have conducted simulations of the performance of an edge lidar system using an injection seeded pulsed Nd:YAG laser at 1.06 microns. The central fringe of a Fabry-Perot etalon is used as a high resolution edge filter to measure the shift of the aerosol return.

  20. Accurate Fiber Length Measurement Using Time-of-Flight Technique

    Science.gov (United States)

    Terra, Osama; Hussein, Hatem

    2016-06-01

    Fiber artifacts of very well-measured length are required for the calibration of optical time domain reflectometers (OTDR). In this paper accurate length measurement of different fiber lengths using the time-of-flight technique is performed. A setup is proposed to measure accurately lengths from 1 to 40 km at 1,550 and 1,310 nm using high-speed electro-optic modulator and photodetector. This setup offers traceability to the SI unit of time, the second (and hence to meter by definition), by locking the time interval counter to the Global Positioning System (GPS)-disciplined quartz oscillator. Additionally, the length of a recirculating loop artifact is measured and compared with the measurement made for the same fiber by the National Physical Laboratory of United Kingdom (NPL). Finally, a method is proposed to relatively correct the fiber refractive index to allow accurate fiber length measurement.

  1. 4. Workshop - Measurement techniques of stationary and transient multiphase flow

    Energy Technology Data Exchange (ETDEWEB)

    Prasser, H.M. (ed.)

    2001-05-01

    In November 2000, the 4th Workshop on Measurement Techniques for Stationary and Transient Multiphase Flows took place in Rossendorf. Three previous workshops of this series were national meetings; this time participants from different countries took part. The programme comprised 14 oral presentations, 9 of which are included in these proceedings in full length. A special highlight of the meeting was the main lecture ''Ultrasonic doppler method for bubbly flow measurement'' of Professor Masanori Aritomi, Dr. Hiroshige Kikura and Dr. Yumiko Suzuki. The workshop again dealt with high-resolution phase distribution and phase velocity measurement techniques based on electrical conductivity, ultrasound, laser light and high-speed cinematography. A number of presentations were dedicated to the application of wire-mesh sensors developed by FZR for different applications used by the Technical Universities of Delft and Munich and the Tokyo Institute of Technology. (orig.)

  2. Electropyroelectric technique for measurement of the thermal effusivity of liquids

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R; Moreno, I; Araujo, C [Facultad de Fisica, Universidad Autonoma de Zacatecas, Calz. Solidaridad Esquina Paseo de la Bufa s/n, C. P. 98060, Zacatecas, Zac. (Mexico); Marin, E, E-mail: emarin63@yahoo.e, E-mail: emarinm@ipn.m [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada, Instituto Politecnico Nacional, LegarIa 694, Colonia Irrigacion, C. P. 11500, Mexico D. F. (Mexico)

    2010-06-09

    The photopyroelectric method has been recognized as a reliable and useful tool for the measurement of the thermal properties of condensed matter samples. Usually the photothermal signal is generated using intensity modulated light beams, whose amplitudes are difficult to maintain stable. In this paper we describe a variant of this technique that uses amplitude modulated electrical current as excitation source, via Joule heating of the metal contact on one side of the pyroelectric sensor. The possibilities of this method, called by us the electropyroelectric technique, for thermal effusivity measurements of liquid samples are shown using test samples of distilled water, ethanol and glycerine. The results obtained for this parameter agree well with the values reported in the literature. Our measurement uncertainties are about 3%, a fact that opens several possible applications.

  3. Soil volumetric water content measurements using TDR technique

    Directory of Open Access Journals (Sweden)

    S. Vincenzi

    1996-06-01

    Full Text Available A physical model to measure some hydrological and thermal parameters in soils will to be set up. The vertical profiles of: volumetric water content, matric potential and temperature will be monitored in different soils. The volumetric soil water content is measured by means of the Time Domain Reflectometry (TDR technique. The result of a test to determine experimentally the reproducibility of the volumetric water content measurements is reported together with the methodology and the results of the analysis of the TDR wave forms. The analysis is based on the calculation of the travel time of the TDR signal in the wave guide embedded in the soil.

  4. Application of stereo photogrammetric techniques for measuring African Elephants

    Directory of Open Access Journals (Sweden)

    A. J Hall-Martin

    1979-01-01

    Full Text Available Measurements of shoulder height and back length of African elephants were obtained by means of stereo photogrammetric techniques. A pair of Zeiss UMK 10/1318 cameras, mounted on a steel frame on the back of a vehicle, were used to photograph the elephants in the Addo Elephant National Park, Republic of South Africa. Several modifications of normal photogrammetry procedure applicable to the field situation (eg. control points and the computation of results (eg. relative orientation are briefly mentioned. Six elephants were immobilised after being photographed and the measurements obtained from them agreed within a range of 1 cm-10 cm with the photogrammetric measurements.

  5. High resolution resonant recombination measurements using evaporative cooling technique

    Energy Technology Data Exchange (ETDEWEB)

    Beilmann, C; Lopez-Urrutia, J R Crespo; Mokler, P H; Ullrich, J, E-mail: christian.beilmann@mpi-hd.mpg.d [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2010-09-15

    We report on a method significantly improving the energy resolution of dielectronic recombination (DR) measurements in electron beam ion traps (EBITs). The line width of DR resonances can be reduced to values distinctly smaller than the corresponding space charge width of the uncompensated electron beam. The experimental technique based on forced evaporative cooling is presented together with test measurements demonstrating its high efficiency. The principle for resolution improvement is elucidated and the limiting factors are discussed. This method opens access to high resolution DR measurements at high ion-electron collision energies required for innermost shell DR in highly charged ions (HCI).

  6. Sound Power Estimation by Laser Doppler Vibration Measurement Techniques

    Directory of Open Access Journals (Sweden)

    G.M. Revel

    1998-01-01

    Full Text Available The aim of this paper is to propose simple and quick methods for the determination of the sound power emitted by a vibrating surface, by using non-contact vibration measurement techniques. In order to calculate the acoustic power by vibration data processing, two different approaches are presented. The first is based on the method proposed in the Standard ISO/TR 7849, while the second is based on the superposition theorem. A laser-Doppler scanning vibrometer has been employed for vibration measurements. Laser techniques open up new possibilities in this field because of their high spatial resolution and their non-intrusivity. The technique has been applied here to estimate the acoustic power emitted by a loudspeaker diaphragm. Results have been compared with those from a commercial Boundary Element Method (BEM software and experimentally validated by acoustic intensity measurements. Predicted and experimental results seem to be in agreement (differences lower than 1 dB thus showing that the proposed techniques can be employed as rapid solutions for many practical and industrial applications. Uncertainty sources are addressed and their effect is discussed.

  7. Plasma scattering of electromagnetic radiation theory and measurement techniques

    CERN Document Server

    Froula, Dustin H; Luhmann, Neville C Jr; Sheffield, John

    2011-01-01

    This work presents one of the most powerful methods of plasma diagnosis in exquisite detail to guide researchers in the theory and measurement techniques of light scattering in plasmas. Light scattering in plasmas is essential in the research and development of fusion energy, environmental solutions, and electronics.Referred to as the "Bible" by researchers the work encompasses fusion and industrial applications essential in plasma research. It is the only comprehensive resource specific to the plasma scattering technique. It provides a wide-range of experimental examples and discussion of the

  8. Brief report: Volume dependence of Grüneisen parameter for solids under extreme compression

    Indian Academy of Sciences (India)

    SANJAY KUMAR; S K SHARMA; O P PANDEY

    2016-08-01

    The Nie expression is amended in such a way that the expression follows the infinite pressure behaviour, i.e., P → ∞or V → 0. A new empirical relationship is developed to predict the values of volume dependence of Grüneisen parameter. NaCl and ε-Fe have been employed to test the suitability of the expression.The results obtained reveal that the relationship is reliable as there is a good agreement between the calculated and the experimental data

  9. Unit vent airflow measurements using a tracer gas technique

    Energy Technology Data Exchange (ETDEWEB)

    Adams, D.G. [Union Electric Company, Fulton, MO (United States); Lagus, P.L. [Lagus Applied Technology, Inc., San Diego, CA (United States); Fleming, K.M. [NCS Corp., Columbus, OH (United States)

    1997-08-01

    An alternative method for assessing flowrates that does not depend on point measurements of air flow velocity is the constant tracer injection technique. In this method one injects a tracer gas at a constant rate into a duct and measures the resulting concentration downstream of the injection point. A simple equation derived from the conservation of mass allows calculation of the flowrate at the point of injection. Flowrate data obtained using both a pitot tube and a flow measuring station were compared with tracer gas flowrate measurements in the unit vent duct at the Callaway Nuclear Station during late 1995 and early 1996. These data are presented and discussed with an eye toward obtaining precise flowrate data for release rate calculations. The advantages and disadvantages of the technique are also described. In those test situations for which many flowrate combinations are required, or in large area ducts, a tracer flowrate determination requires fewer man-hours than does a conventional traverse-based technique and does not require knowledge of the duct area. 6 refs., 10 figs., 6 tabs.

  10. Measurement of epithermal neutrons by a coherent demodulation technique

    CERN Document Server

    Horiuchi, N; Takahashi, H; Kobayashi, H; Harasawa, S

    2000-01-01

    Epithermal neutrons have been measured using a neutron dosimeter via a coherent demodulation technique. This dosimeter consists of CsI(Tl)-photodiode scintillation detectors, four of which are coupled to neutron-gamma converting foils of various sizes. Neutron-gamma converting foils of In, Au and Co materials were used, each of which has a large capture cross section which peaks in the epithermal neutron energy region. The type of foil was selected according to the material properties that best correspond to the energy of the epithermal neutrons to be measured. In addition, the proposed technique was applied using Au-foils in order to measure the Cd ratio. The validity of the proposed technique was examined using an sup 2 sup 4 sup 1 Am-Be source placed in a testing stack of polyethylene blocks, and the results were compared with the theoretical values calculated by the Monte Carlo calculation. Finally, the dosimeter was applied for measuring epithermal neutrons and the Cd ratio in an experimental beam-tube o...

  11. Noble Gas Measurement and Analysis Technique for Monitoring Reprocessing Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Charlton, William S [Univ. of California, Berkeley, CA (United States)

    1999-09-01

    An environmental monitoring technique using analysis of stable noble gas isotopic ratios on-stack at a reprocessing facility was developed. This technique integrates existing technologies to strengthen safeguards at reprocessing facilities. The isotopic ratios are measured using a mass spectrometry system and are compared to a database of calculated isotopic ratios using a Bayesian data analysis method to determine specific fuel parameters (e.g., burnup, fuel type, fuel age, etc.). These inferred parameters can be used by investigators to verify operator declarations. A user-friendly software application (named NOVA) was developed for the application of this technique. NOVA included a Visual Basic user interface coupling a Bayesian data analysis procedure to a reactor physics database (calculated using the Monteburns 3.01 code system). The integrated system (mass spectrometry, reactor modeling, and data analysis) was validated using on-stack measurements during the reprocessing of target fuel from a U.S. production reactor and gas samples from the processing of EBR-II fast breeder reactor driver fuel. These measurements led to an inferred burnup that matched the declared burnup with sufficient accuracy and consistency for most safeguards applications. The NOVA code was also tested using numerous light water reactor measurements from the literature. NOVA was capable of accurately determining spent fuel type, burnup, and fuel age for these experimental results. Work should continue to demonstrate the robustness of this system for production, power, and research reactor fuels.

  12. Objective techniques for psychological assessment, phase 2. [techniques for measuring human performance during space flight stress

    Science.gov (United States)

    Wortz, E. C.; Saur, A. J.; Nowlis, D. P.; Kendall, M. P.

    1974-01-01

    Results are presented of an initial experiment in a research program designed to develop objective techniques for psychological assessment of individuals and groups participating in long-duration space flights. Specifically examined is the rationale for utilizing measures of attention as an objective assessment technique. Subjects participating in the experiment performed various tasks (eg, playing matrix games which appeared on a display screen along with auditory stimuli). The psychophysiological reactions of the subjects were measured and are given. Previous research of various performance and psychophysiological methods of measuring attention is also discussed. The experiment design (independent and dependent variables) and apparatus (computers and display devices) are described and shown. Conclusions and recommendations are presented.

  13. Gamma ray densitometry techniques for measuring of volume fractions

    Energy Technology Data Exchange (ETDEWEB)

    Affonso, Renato Raoni Werneck; Silva, Ademir Xavier da; Salgado, Cesar Marques, E-mail: raoniwa@yahoo.com.br, E-mail: ademir@nuclear.ufrj.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Knowledge of the volume fraction in a multiphase flow is of key importance in predicting the performance of many systems and processes. It is therefore an important parameter to characterize such flows. In the context of nuclear techniques, the gamma ray densitometry is promising and this is due to its non-invasive characteristics and very reliable results. It is used in several applications for multiphase flows (water-oil-air), which are employed tools such as: computational fluid dynamics, artificial neural networks and statistical methods of radiation transport, such as the Monte Carlo method. Based on the gamma radiation techniques for measurements of volume fractions, the aim of this paper is to present several techniques developed for this purpose. (author)

  14. A new technique to measure the differential XAFS spectrum

    Science.gov (United States)

    Wu, Min; Zheng, Li-Rong; Chu, Sheng-Qi; Zhou, Ai-Yu; Zhang, Jing; Hu, Tian-Dou

    2016-04-01

    A new technique has been developed for direct measurement of the differential X-ray absorption fine structure (XAFS) spectrum by the energy-modulation method. To acquire the energy-oscillating incident X-ray beam, a piezoelectric actuator is used to control the double-crystal monochromator. A logarithmic converter circuit and a lock-in amplifier are used to extract the modulated signals. The normal and differential XAFS spectra of the Mn K-edge of Li2MnO3 have been collected. The X-ray-absorption near-edge-structure (XANES) spectra verify that the signal-to-noise ratio has been greatly improved by the new technique, and the extended X-ray absorption fine structure (EXAFS) spectra demonstrate that this new technique can efficiently enhance the signals of the backscattering atoms. Supported by NSFC (11175202)

  15. Fourier transform approach in modulation technique of experimental measurements.

    Science.gov (United States)

    Khazimullin, M V; Lebedev, Yu A

    2010-04-01

    An application of Fourier transform approach in modulation technique of experimental studies is considered. This method has obvious advantages compared with traditional lock-in amplifiers technique--simple experimental setup, a quickly available information on all the required harmonics, high speed of data processing using fast Fourier transform algorithm. A computationally simple, fast and accurate Fourier coefficients interpolation (FCI) method has been implemented to obtain a useful information from harmonics of a multimode signal. Our analysis shows that in this case FCI method has a systematical error (bias) of a signal parameters estimation, which became essential for the short data sets. Hence, a new differential Fourier coefficients interpolation (DFCI) method has been suggested, which is less sensitive to a presence of several modes in a signal. The analysis has been confirmed by simulations and measurements of a quartz wedge birefringence by means of the photoelastic modulator. The obtained bias, noise level, and measuring speed are comparable and even better than in lock-in amplifier technique. Moreover, presented DFCI method is expected to be promised candidate for using in actively developing imaging systems based on the modulation technique requiring fast digital signal processing of large data sets.

  16. A new measuring technique of soil thermal inertia

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Thermal inertia is the function of substance density,heat capacity and heat diffusivity,and is an important parameter for researching the process of surface heat balance using remote sensing technique.In this paper,using soil heat plates,infrared thermometer,data logger and other instruments,by man-controlled changing the solar radiation status on the soil samples,the authors gave a new method to measure soil thermal inertia.Using the continuously surveying data of soil heat flux and infrared radiation temperature,thermal inertia can be calculated easily.Based on the thermal inertia calculation of three soil samples with different water content,good results were abtained by the authors,so this method is feasible.Meanwhile,this measuring technique is also a new attempt.

  17. A new measuring technique of soil thermal inertia

    Institute of Scientific and Technical Information of China (English)

    孙晓敏; 朱治林; 唐新斋; 苏红波; 张仁华

    2000-01-01

    Thermal inertia is the function of substance density, heat capacity and heat diffusivity, and is an important parameter for researching the process of surface heat balance using remote sensing technique. In this paper, using soil heat plates, infrared thermometer, data logger and other instruments, by man-controlled changing the solar radiation status on the soil samples, the authors gave a new method to measure soil thermal inertia. Using the continuously surveying data of soil heat flux and infrared radiation temperature, thermal inertia can be calculated easily. Based on the thermal inertia calculation of three soil samples with different water content, good results were abtained by the authors, so this method is feasible. Meanwhile, this measuring technique is also a new attempt.

  18. Verification of long-term load measurement technique

    DEFF Research Database (Denmark)

    Schmidt Paulsen, Uwe

    The present report is the final effort of tasks carried out under UPWIND WP1B2 transmission and conversion, which describes: 1) results and recommendations developed in the course of developing the long-term load measurement technique 2) the hardware details, type of sensors and location, data...... storage and 3) data analysis technique to verify design load assumptions. The work is carried out under Contract no 019945 (SES6) "UPWIND" within the European Commission The interaction between the mechanical and electrical generator subsystems is described rudimentarily, based primarily on HAWC2...... simulations below stall of the mechanical system with simple generator and gearbox systems. The electrical system simulations were not carried out as intended in DOW[2], but indications of the conditions for establishing the interaction have been described by measurements and by argument, that this might have...

  19. APPLICATION OF NOVEL NEUTRON CORRELATION TECHNIQUES TO NUCLEAR MATERIAL MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Sale, K

    2006-06-09

    Confirmation of the fissile mass of a system containing plutonium can be done using neutron multiplicity techniques. This can be accomplished with a detector system that is smaller and less costly than a standard neutron multiplicity counter (NMC). Also the fissile mass of a uranium containing system can be confirmed by passive means. Recent work at Lawrence Livermore National Laboratory has demonstrated that simple slab neutron detectors and a novel approach to data acquisition and analysis can be used to make an accurate measurement of the mass of fissile materials. Purely passive measurement of kilogram quantities of highly enriched uranium (HEU) have also been shown to be feasible. In this paper we discuss calculational tools for assessing the application of these techniques to fissile material transparency regimes. The tools required to adequately model the correlations and their application will be discussed.

  20. 3D interferometric shape measurement technique using coherent fiber bundles

    Science.gov (United States)

    Zhang, Hao; Kuschmierz, Robert; Czarske, Jürgen

    2017-06-01

    In-situ 3-D shape measurements with submicron shape uncertainty of fast rotating objects in a cutting lathe are expected, which can be achieved by simultaneous distance and velocity measurements. Conventional tactile methods, coordinate measurement machines, only support ex-situ measurements. Optical measurement techniques such as triangulation and conoscopic holography offer only the distance, so that the absolute diameter cannot be retrieved directly. In comparison, laser Doppler distance sensors (P-LDD sensor) enable simultaneous and in-situ distance and velocity measurements for monitoring the cutting process in a lathe. In order to achieve shape measurement uncertainties below 1 μm, a P-LDD sensor with a dual camera based scattered light detection has been investigated. Coherent fiber bundles (CFB) are employed to forward the scattered light towards cameras. This enables a compact and passive sensor head in the future. Compared with a photo detector based sensor, the dual camera based sensor allows to decrease the measurement uncertainty by the order of one magnitude. As a result, the total shape uncertainty of absolute 3-D shape measurements can be reduced to about 100 nm.

  1. Measurement Techniques for Electrothermal-Chemical Gun Diagnostics

    Science.gov (United States)

    1993-12-01

    conductors of a circuit ( Askeland 1985). This technique has been successfully applied to other experimental work including the pressure measurements made in...Fe2O4 ( Askeland 1985). Ferrites are implemented by wrapping the power cords and coaxial data lines of all electronics equipment tightly for several... Askeland , D. R. The Sciece and Engineering of Materials. Prindle, Weber, and Schmidt, 1985. Burden. H. S., and D. D. Shear. "Transient Noise in Electronic

  2. Experimental Methods Using Photogrammetric Techniques for Parachute Canopy Shape Measurements

    Science.gov (United States)

    Jones, Thomas W.; Downey, James M.; Lunsford, Charles B.; Desabrais, Kenneth J.; Noetscher, Gregory

    2007-01-01

    NASA Langley Research Center in partnership with the U.S. Army Natick Soldier Center has collaborated on the development of a payload instrumentation package to record the physical parameters observed during parachute air drop tests. The instrumentation package records a variety of parameters including canopy shape, suspension line loads, payload 3-axis acceleration, and payload velocity. This report discusses the instrumentation design and development process, as well as the photogrammetric measurement technique used to provide shape measurements. The scaled model tests were conducted in the NASA Glenn Plum Brook Space Propulsion Facility, OH.

  3. Measurements of diversity gain and radiation efficiency of the eleven antenna by using different measurement techniques

    DEFF Research Database (Denmark)

    Yang, Jian; Pivnenko, Sergey; Laitinen, Tommi

    2010-01-01

    This paper presents measurement results of diversity gain and radiation efficiency by using three different measurement techniques: reverberation chamber, spherical near-field anechoic chamber, and multi-probe anechoic chamber. The results are measured over a large 2–8 GHz bandwidth which...

  4. Electromagnetic techniques for industrial plant process measurements and quality control

    Energy Technology Data Exchange (ETDEWEB)

    Bramanti, M. (Consiglio Nazionale delle Ricerche, Pisa (Italy). Ist. di Elaborazione della Informazione)

    1992-04-01

    In recent years, new real time non-destructive measuring techniques have been developed based on the use of miniaturized components capable of generating, amplifying and elaborating microwave signals (within the range of tenths of a volt and hundreds of milliamps). All these techniques for the measurement of typical process parameters or the non-destructive testing of materials are based on the interaction of radiation with the material or system under examination and make use of the most modern types of data acquisition technology. This article surveys the sensors and measuring instruments which make use of electromagnetic radiation to acquire information concerning the properties of an examined material or system based on their interactions with electromagnetic fields. A few applications are illustrated, e.g., the measurement of unburnt coal in power plant fly ash, the measurement of the quantity of solid particles present in fluidized beds and the verification of the properties of dielectric materials. In each case, the optimum degree of resolution of these devices is made evident.

  5. Vibration frequency measurement using a local multithreshold technique.

    Science.gov (United States)

    Ferrer, Belen; Espinosa, Julian; Roig, Ana B; Perez, J; Mas, D

    2013-11-01

    In this paper, we demonstrate the use of a video camera for measuring the frequency of small-amplitude vibration movements. The method is based on image acquisition and multilevel thresholding and it only requires a video camera with high enough acquisition rate, not being necessary the use of targets or auxiliary laser beams. Our proposal is accurate and robust. We demonstrate the technique with a pocket camera recording low-resolution videos with AVI-JPEG compression and measuring different objects that vibrate in parallel or perpendicular direction to the optical sensor. Despite the low resolution and the noise, we are able to measure the main vibration modes of a tuning fork, a loudspeaker and a bridge. Results are successfully compared with design parameters and measurements with alternative devices.

  6. Data fusion techniques for incomplete measurement of trajectory

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper focuses on data processing for incomplete measurementof trajectory (IMT) in aerospace mea- surement and control. The IMT means that the principal equipment loses the measured data during some intervals so that trajectory parameters (position, velocity, etc.) cannot be determined independently. Based on a joint model for trajectory estimation with reduced parameter, a fusion way is put forth by making full use of measured data from auxiliary equipment with lower precision. In the superposition intervals of measurement between principal and auxiliary equipment, the technique of diagnosing and estimating system errors is applied to improving the estimate precision of trajectory parameters (TP) and determining the precision after data fusion. In practical test, this method operates so successfully that it can not only provide complete TP but improve their precision remarkably. Meanwhile, this way is also applicable to other problems of incomplete measurement.

  7. A new distensibility technique to measure sphincter of Oddi function

    DEFF Research Database (Denmark)

    Kunwald, Peter; Drewes, Asbjørn Mohr; Kjær, D.;

    2010-01-01

    . Methods The SO probe was constructed to measure eight cross-sectional areas (CSA) along a length of 25 mm inside a saline-filled bag. To validate the technique for profiling the SO, six perspex cylinders with different CSAs were measured nine times to assess reproducibility and accuracy. Key Results...... probe and validating it for measurements in the SO. In order to get a better physiological understanding of the SO the aims were to show the sphincter profile in vivo and motility patterns of SO in pilot studies using volunteers that were experiencing biliary type pain but had normal SO manometry...... Reproducibility and accuracy for these measurements were good. The probe performed well in bench tests and was therefore tested in four humans. The data indicated that it was possible to make distensions in the human SO and that a geometric sphincter profile could be obtained. Conclusions & Inferences The probe...

  8. Improved Tandem Measurement Techniques for Aerosol Particle Analysis

    Science.gov (United States)

    Rawat, Vivek Kumar

    Non-spherical, chemically inhomogeneous (complex) nanoparticles are encountered in a number of natural and engineered environments, including combustion systems (which produces highly non-spherical aggregates), reactors used in gas-phase materials synthesis of doped or multicomponent materials, and in ambient air. These nanoparticles are often highly diverse in size, composition and shape, and hence require determination of property distribution functions for accurate characterization. This thesis focuses on development of tandem mobility-mass measurement techniques coupled with appropriate data inversion routines to facilitate measurement of two dimensional size-mass distribution functions while correcting for the non-idealities of the instruments. Chapter 1 provides the detailed background and motivation for the studies performed in this thesis. In chapter 2, the development of an inversion routine is described which is employed to determine two dimensional size-mass distribution functions from Differential Mobility Analyzer-Aerosol Particle Mass analyzer tandem measurements. Chapter 3 demonstrates the application of the two dimensional distribution function to compute cumulative mass distribution function and also evaluates the validity of this technique by comparing the calculated total mass concentrations to measured values for a variety of aerosols. In Chapter 4, this tandem measurement technique with the inversion routine is employed to analyze colloidal suspensions. Chapter 5 focuses on application of a transverse modulation ion mobility spectrometer coupled with a mass spectrometer to study the effect of vapor dopants on the mobility shifts of sub 2 nm peptide ion clusters. These mobility shifts are then compared to models based on vapor uptake theories. Finally, in Chapter 6, a conclusion of all the studies performed in this thesis is provided and future avenues of research are discussed.

  9. Measuring glioma volumes: A comparison of linear measurement based formulae with the manual image segmentation technique

    Directory of Open Access Journals (Sweden)

    Sanjeev A Sreenivasan

    2016-01-01

    Conclusions: Manual region of interest-based image segmentation is the standard technique for measuring glioma volumes. For routine clinical use, the simple formula v = abc/2 (or the formula for volume of an ellipsoid could be used as alternatives.

  10. Spherical near-field antenna measurements — The most accurate antenna measurement technique

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2016-01-01

    The spherical near-field antenna measurement technique combines several advantages and generally constitutes the most accurate technique for experimental characterization of radiation from antennas. This paper/presentation discusses these advantages, briefly reviews the early history and present...... status, and addresses future challenges for spherical near-field antenna measurements; in particular, from the viewpoint of the DTU-ESA Spherical Near-Field Antenna Test Facility....

  11. Radiographic measurements of hallux angles: a review of current techniques.

    Science.gov (United States)

    Srivastava, Subodh; Chockalingam, N; El Fakhri, Tarek

    2010-03-01

    Radiographic angles are commonly used in patients with hallux valgus deformity to assess the severity, plan surgery, assess outcome and compare results. Many different manual methods have been used, but are prone to error. More recently computer-assisted methods using software have become available. To review the different methods that have been used to measure radiographic angles in hallux valgus. A general literature search using relevant key words was undertaken using databases such as Medline, Embase, Cinahl and Cochrane Library. REVIEW FINDINGS AND DISCUSSION: The manual methods used are prone to errors. The reliability can be improved by using standardised radiographic technique and measurement technique using specific reference points. Computer-assisted methods using software, might improve reliability of measurements. Further studies are needed to assess if these methods are easy to use, and to compare different software's that are available. Specifically designed software for the foot might further improve the reliability of radiographic measurements in hallux valgus. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  12. Entrance surface dose measurements in mammography using thermoluminescence technique

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada Unidad Legaria del IPM Av. Legaria 694, 11500 Mexico D.F. (Mexico); Vega C, H.R.; Manzanares A, E [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Apdo. Postal 336, 98000 Zacatecas (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-lztapalapa, Av. San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico); Gonzalez, P.R. [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico Toluca, 52045 Salazar Estado de Mexico (Mexico)

    2007-07-01

    Full text: Of the various techniques that can be used for personnel dosimetry, thermoluminescence dosimetry (TLD) has emerged as a superior technique due to its manifold advantages over other methods of dose estimation. Various phosphors have been therefore investigated regarding their suitability for dosimetry. In this paper, a dosimetry system based on thermally stimulated luminescence (TSL) from zirconium oxide phosphors embedded in polytetrafluorethylene (ZrO{sub 2}+PTFE) was developed for entrance surface doses (ES) measurements in mammography. Small ZrO{sub 2} pellets of 5 mm in diameter and 0.8 mm in thickness were used. The reproducibility of measurements and linearity of ZrO{sub 2} were also studied. The results were compared with those obtained from LiF:Mg,Cu,P usually used for the determination of absorbed dose in mammography. Measurements both per unit air kerma and In vivo were performed using a mammography unit model DMR (General Electric). The results showed that ZrO{sub 2} TLDs can be used for the same X-ray dosimetry applications as LiF:Mg,Cu,P, with each type having the disadvantage of a response dependent on energy, particularly at low energies. These results indicate a considerable potential for use in routine control and In vivo ES measurements in mammography. (Author)

  13. Flowing dusty plasma experiments: generation of flow and measurement techniques

    Science.gov (United States)

    Jaiswal, S.; Bandyopadhyay, P.; Sen, A.

    2016-12-01

    A variety of experimental techniques for the generation of subsonic/supersonic dust fluid flows and means of measuring such flow velocities are presented. The experiments have been carried out in a \\Pi -shaped dusty plasma experimental device with micron size kaolin/melamine formaldehyde particles embedded in a background of argon plasma created by a direct current glow discharge. A stationary dust cloud is formed over the cathode region by precisely balancing the pumping speed and gas flow rate. A flow of dust particles/fluid is generated by additional gas injection from a single or dual locations or by altering the dust confining potential. The flow velocity is then estimated by three different techniques, namely, by super particle identification code, particle image velocimetry analysis and the excitation of dust acoustic waves. The results obtained from these three different techniques along with their merits and demerits are discussed. An estimation of the neutral drag force responsible for the generation as well as the attenuation of the dust fluid flow is made. These techniques can be usefully employed in laboratory devices to investigate linear and non-linear collective excitations in a flowing dusty plasma.

  14. Laboratory technique for quantitative thermal emissivity measurements of geological samples

    Indian Academy of Sciences (India)

    George Mathew; Archana Nair; T K Gundu Rao; Kanchan Pande

    2009-08-01

    Thermal infrared spectroscopy is a powerful technique for the compositional analysis of geological materials. The spectral feature in the mid-IR region is diagnostic of the mineralogy and spectral signatures of mixtures of minerals that add linearly, and therefore, can be used as an important tool to determine the mineralogy of rocks in the laboratory and remotely for planetary exploration. The greatest challenge in the emission measurement lies in the measurement of the weak thermal photons emitted from geological materials in a laboratory setup, and accurately records the temperature of the rock sample. The present work pertains to the details of a new Thermal Emission Spectrometer (TES) laboratory that has been developed under the ISRO Planetary Science and Exploration (PLANEX) programme, for emission related mineralogical investigations of planetary surfaces. The focus of the paper is on the acquisition and calibration technique for obtaining emissivity, and the deconvolution procedure to obtain the modal abundances of the thermal emission spectra in the range of 6–25 m using Fourier Transform Infrared (FTIR) spectroscopy. The basic technique is adopted from the work of Ruff et al (1997). This laboratory at the Department of Earth Sciences, IIT-Bombay is currently developing pure end mineral library of mineral particulates (> 65 m), and adding new end members to the existing ASU spectral library. The paper argues the need for considering Lunar Orbiter Thermal Emission Spectrometer (LOTES) for future Indian Moon mission programme (Chandrayan-II) to determine evidences of varied lithologies on the lunar surface.

  15. A Comparison of Stellar Elemental Abundance Techniques and Measurements

    CERN Document Server

    Hinkel, Natalie R; Pagano, Michael D; Desch, Steven J; Anbar, Ariel D; Adibekyan, Vardan; Blanco-Cuaresma, Sergi; Carlberg, Joleen K; Mena, Elisa Delgado; Liu, Fan; Nordlander, Thomas; Sousa, Sergio G; Korn, Andreas; Gruyters, Pieter; Heiter, Ulrike; Jofre, Paula; Santos, Nuno C; Soubiran, Caroline

    2016-01-01

    Stellar elemental abundances are important for understanding the fundamental properties of a star or stellar group, such as age and evolutionary history, as well as the composition of an orbiting planet. However, as abundance measurement techniques have progressed, there has been little standardization between individual methods and their comparisons. As a result, different stellar abundance procedures determine measurements that vary beyond quoted error for the same elements within the same stars (Hinkel et al. 2014). The purpose of this paper is to better understand the systematic variations between methods and offer recommendations for producing more accurate results in the future. We have invited a number of participants from around the world (Australia, Portugal, Sweden, Switzerland, and USA) to calculate ten element abundances (C, O, Na, Mg, Al, Si, Fe, Ni, Ba, and Eu) using the same stellar spectra for four stars (HD361, HD10700, HD121504, HD202206). Each group produced measurements for each of the sta...

  16. ONLINE GRINDING WHEEL WEAR COMPENSATION BY IMAGE BASED MEASURING TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    WAN Daping; HU Dejin; WU Qi; ZHANG Yonghong

    2006-01-01

    Automatic compensation of grinding wheel wear in dry grinding is accomplished by an image based online measurement method. A kind of PC-based charge-coupled device image recognition system is schemed out, which detects the topography changes of the grinding wheel surface. Profile data, which corresponds to the wear and the topography, is measured by using a digital image processing method. The grinding wheel wear is evaluated by analyzing the position deviation of the grinding wheel edge. The online wear compensation is achieved according to the measure results. The precise detection and automatic compensation system is integrated into an open structure CNC curve grinding machine. A practical application is carried out to fulfil the precision curve grinding. The experimental results confirm the benefits of the proposed techniques, and the online detection accuracy is less than 5 μm. The grinding machine provides higher precision according to the in-process grinding wheel error compensation.

  17. Velocity of detonation (VOD measurement techniques - practical approach

    Directory of Open Access Journals (Sweden)

    Aruna Dhanraj Tete

    2013-06-01

    Full Text Available Velocity of Detonation (VOD is an important measure characteristics parameter of explosive material. The performance of explosive invariably depends on the velocity of detonation. The power/ strength of explosive to cause fragmentation of the solid structure determine the efficiency of the Blast performed. It is an established fact that measuring velocity of detonation gives a good indication of the strength and hence the performance of the explosive. In this survey various VOD measurement techniques such as electric, nonelectric and fibre optic have been discussed. To aid the discussion some commercially available VOD meter comparison are also presented. After review of the existing units available commercially and study of their respective merits and demerits, feature of an ideal system is proposed. 

  18. Application of Sensing Techniques to Cellular Force Measurement

    Directory of Open Access Journals (Sweden)

    James H.-C. Wang

    2010-11-01

    Full Text Available Cell traction forces (CTFs are the forces produced by cells and exerted on extracellular matrix or an underlying substrate. CTFs function to maintain cell shape, enable cell migration, and generate and detect mechanical signals. As such, they play a vital role in many fundamental biological processes, including angiogenesis, inflammation, and wound healing. Therefore, a close examination of CTFs can enable better understanding of the cellular and molecular mechanisms of such processes. To this end, various force-sensing techniques for CTF measurement have been developed over the years. This article will provide a concise review of these sensing techniques and comment on the needs for improved force-sensing technologies for cell mechanics and biology research.

  19. Precise measurement technique for the stable acoustic cavitation bubble

    Institute of Scientific and Technical Information of China (English)

    HUANG Wei; CHEN Weizhong; LIU Yanan; GAO Xianxian; JIANG Lian; XU Junfeng; ZHU Yifei

    2005-01-01

    Based on the periodic oscillation of the stable acoustic cavitation bubble, we present a precise measurement technique for the bubble evolution. This technique comprises the lighting engineering of pulsing laser beam whose phase can be digitally shifted, and the long distance microphotographics. We used a laser, an acousto-optic modulator, a pulse generator, and a long distance microscope. The evolution of a levitated bubble can be directly shown by a series of bubble's images at different phases. Numerical simulation in the framework of the Rayleigh-Plesset bubble dynamics well supported the experimental result, and the ambient radius of the bubble, an important parameter related to the mass of the gas inside the bubble, was obtained at the same time.

  20. Repeated High-Precision Gravity and GPS Measurement Techniques

    Science.gov (United States)

    Gettings, P.; Harris, R. N.; Allis, R.; Chapman, D. S.

    2003-12-01

    Repeated high-precision gravity and GPS measurements are becoming a common tool for tracking changes in subsurface reservoirs. Despite this, there is little literature which discusses measurement techniques and the expected errors. Our research has focused on improving measurement techniques to be applied to ground water and geothermal steam reservoirs, including quantifying the minimum error levels with modern equipment. We applied these methods in two studies: ground water monitoring of the southern Salt Lake valley, Utah, USA, and steam monitoring of The Geysers geothermal field, California, USA. Gravity measurements using modern relative high-precision meters, such as Scintrex CG-3Ms or L&R E series, can now be routinely made to an accuracy of 5 μ Gal. Such accuracy requires the use of time series analysis at each station, and non-linear instrument drift functions. Modern computerized meters are capable of internally storing a time series of measurements for each station; older meters can often be fitted to log such data to a field computer. This time series, typically of 10-15 minute duration in our work, can then be analyzed in several ways to produce stable estimates of the gravity reading. In particular, our research has emphasized using a weighted arithmetic average (for long occupations), or a Thiele extrapolation scheme (for shorter station occupations). Instrument drift is removed through a superposition of a linear long-term drift function, and an empirical staircase function formed from differences between repeated station occupations. To achieve high-accuracy GPS measurements while maximizing the number of field stations in a survey, rapid-static measurements are necessary. We have tested the effect of occupation time and processing schemes on the absolute accuracy of the resulting GPS position. Using a post-processing differential method with a fixed (but not necessarily continuous) base station within 15 km, positioning error of <4 cm vertical is

  1. Damage detection technique by measuring laser-based mechanical impedance

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeonseok; Sohn, Hoon [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (Daehak-ro 291, Yuseong-gu, Daejeon 305-701) (Korea, Republic of)

    2014-02-18

    This study proposes a method for measurement of mechanical impedance using noncontact laser ultrasound. The measurement of mechanical impedance has been of great interest in nondestructive testing (NDT) or structural health monitoring (SHM) since mechanical impedance is sensitive even to small-sized structural defects. Conventional impedance measurements, however, have been based on electromechanical impedance (EMI) using contact-type piezoelectric transducers, which show deteriorated performances induced by the effects of a) Curie temperature limitations, b) electromagnetic interference (EMI), c) bonding layers and etc. This study aims to tackle the limitations of conventional EMI measurement by utilizing laser-based mechanical impedance (LMI) measurement. The LMI response, which is equivalent to a steady-state ultrasound response, is generated by shooting the pulse laser beam to the target structure, and is acquired by measuring the out-of-plane velocity using a laser vibrometer. The formation of the LMI response is observed through the thermo-mechanical finite element analysis. The feasibility of applying the LMI technique for damage detection is experimentally verified using a pipe specimen under high temperature environment.

  2. Experimental measurements of the thermal conductivity of ash deposits: Part 1. Measurement technique

    Energy Technology Data Exchange (ETDEWEB)

    A. L. Robinson; S. G. Buckley; N. Yang; L. L. Baxter

    2000-04-01

    This paper describes a technique developed to make in situ, time-resolved measurements of the effective thermal conductivity of ash deposits formed under conditions that closely replicate those found in the convective pass of a commercial boiler. Since ash deposit thermal conductivity is thought to be strongly dependent on deposit microstructure, the technique is designed to minimize the disturbance of the natural deposit microstructure. Traditional techniques for measuring deposit thermal conductivity generally do not preserve the sample microstructure. Experiments are described that demonstrate the technique, quantify experimental uncertainty, and determine the thermal conductivity of highly porous, unsintered deposits. The average measured conductivity of loose, unsintered deposits is 0.14 {+-} 0.03 W/(m K), approximately midway between rational theoretical limits for deposit thermal conductivity.

  3. Protocol of measurement techniques - Project colored solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Schueler, A.; Chambrier, E. De; Roecker, Ch.; Scartezzini, J.-L.

    2004-08-15

    This illustrated annual report for the Swiss Federal Office of Energy (SFOE) takes a look at work done at the Swiss Federal Institute of Technology in Lausanne, Switzerland, on multi-layer, thin-film interference coatings for solar collector glazing. The correct combinations of refractive indices and film thickness are discussed. The authors state that corresponding multi-layered thin film stacks will have to be realised experimentally in a controlled and reproducible way. New thin film materials are to be tailored to exhibit optimised optical and ageing properties. The development of these coatings is to be based on various measurement techniques, such as spectro-photometry, measurements of total power throughput by means of a solar simulator, spectroscopic ellipsometry, scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The paper provides many examples of typical data and explains which film properties can be inferred from each method and thus describes both the function and purpose of the different measurement techniques.

  4. Equipment and Experimental Technique For Temperature Measurements In Deep Boreholes

    Science.gov (United States)

    Khristoforov, A.

    The technique of temperature measurements is highly informative since any dynami- cal processes in the boreholes and in the vicinities are accompanied by thermal effects. Electronics and equipment for remote measurements in the boreholes are briefly dis- cussed in the report. It includes a deep instrument, cable winch and surface recording unit placed onboard a car. The temperature dependent frequency modulated signal is used in deep instrument. A cable of original construction was developed for chute-lift operations. It has a signal and power channel at the same time and play the depth me- ter. The surface recording unit includes power supply for deep instruments, receiver, frequency meter and indicator. A personal computer is used for the measurement nu- merical control. Energy for the electronics is supplied by a car battery. Self sufficiency and high accuracy are specialities of the equipment. Using the technique and equip- ment we made the experimental study of temperature in the boreholes of the East European platform, Middle Asia, West Siberia, Kamchatka and other regions. Most of our temperatures and temperature gradients have been used for mapping.

  5. A Comparison of Stellar Elemental Abundance Techniques and Measurements

    Science.gov (United States)

    Hinkel, Natalie R.; Young, Patrick A.; Pagano, Michael D.; Desch, Steven J.; Anbar, Ariel D.; Adibekyan, Vardan; Blanco-Cuaresma, Sergi; Carlberg, Joleen K.; Delgado Mena, Elisa; Liu, Fan; Nordlander, Thomas; Sousa, Sergio G.; Korn, Andreas; Gruyters, Pieter; Heiter, Ulrike; Jofré, Paula; Santos, Nuno C.; Soubiran, Caroline

    2016-09-01

    Stellar elemental abundances are important for understanding the fundamental properties of a star or stellar group, such as age and evolutionary history, as well as the composition of an orbiting planet. However, as abundance measurement techniques have progressed, there has been little standardization between individual methods and their comparisons. As a result, different stellar abundance procedures determine measurements that vary beyond the quoted error for the same elements within the same stars. The purpose of this paper is to better understand the systematic variations between methods and offer recommendations for producing more accurate results in the future. We invited a number of participants from around the world (Australia, Portugal, Sweden, Switzerland, and the United States) to calculate 10 element abundances (C, O, Na, Mg, Al, Si, Fe, Ni, Ba, and Eu) using the same stellar spectra for four stars (HD 361, HD 10700, HD 121504, and HD 202206). Each group produced measurements for each star using (1) their own autonomous techniques, (2) standardized stellar parameters, (3) a standardized line list, and (4) both standardized parameters and a line list. We present the resulting stellar parameters, absolute abundances, and a metric of data similarity that quantifies the homogeneity of the data. We conclude that standardization of some kind, particularly stellar parameters, improves the consistency between methods. However, because results did not converge as more free parameters were standardized, it is clear there are inherent issues within the techniques that need to be reconciled. Therefore, we encourage more conversation and transparency within the community such that stellar abundance determinations can be reproducible as well as accurate and precise.

  6. Advanced Techniques for Power System Identification from Measured Data

    Energy Technology Data Exchange (ETDEWEB)

    Pierre, John W.; Wies, Richard; Trudnowski, Daniel

    2008-11-25

    Time-synchronized measurements provide rich information for estimating a power-system's electromechanical modal properties via advanced signal processing. This information is becoming critical for the improved operational reliability of interconnected grids. A given mode's properties are described by its frequency, damping, and shape. Modal frequencies and damping are useful indicators of power-system stress, usually declining with increased load or reduced grid capacity. Mode shape provides critical information for operational control actions. This project investigated many advanced techniques for power system identification from measured data focusing on mode frequency and damping ratio estimation. Investigators from the three universities coordinated their effort with Pacific Northwest National Laboratory (PNNL). Significant progress was made on developing appropriate techniques for system identification with confidence intervals and testing those techniques on field measured data and through simulation. Experimental data from the western area power system was provided by PNNL and Bonneville Power Administration (BPA) for both ambient conditions and for signal injection tests. Three large-scale tests were conducted for the western area in 2005 and 2006. Measured field PMU (Phasor Measurement Unit) data was provided to the three universities. A 19-machine simulation model was enhanced for testing the system identification algorithms. Extensive simulations were run with this model to test the performance of the algorithms. University of Wyoming researchers participated in four primary activities: (1) Block and adaptive processing techniques for mode estimation from ambient signals and probing signals, (2) confidence interval estimation, (3) probing signal design and injection method analysis, and (4) performance assessment and validation from simulated and field measured data. Subspace based methods have been use to improve previous results from block

  7. International Conference Automation : Challenges in Automation, Robotics and Measurement Techniques

    CERN Document Server

    Zieliński, Cezary; Kaliczyńska, Małgorzata

    2016-01-01

    This book presents the set of papers accepted for presentation at the International Conference Automation, held in Warsaw, 2-4 March of 2016. It presents the research results presented by top experts in the fields of industrial automation, control, robotics and measurement techniques. Each chapter presents a thorough analysis of a specific technical problem which is usually followed by numerical analysis, simulation, and description of results of implementation of the solution of a real world problem. The presented theoretical results, practical solutions and guidelines will be valuable for both researchers working in the area of engineering sciences and for practitioners solving industrial problems. .

  8. Advanced spherical near-field antenna measurement techniques

    DEFF Research Database (Denmark)

    Nielsen, Jeppe Majlund; Pivnenko, Sergey; Breinbjerg, Olav

    2011-01-01

    The DTU-ESA facility has since the 1980es provided highly accurate antenna radiation pattern measurements and gain calibration by use of the probe corrected spherical nearfield technique, both for ESA (the European Space Agency) and other customers and continues to do so. Recent years activities...... and showing the capabilities of each participating facility. A special campaign was carried out with the aim of establishing a reference radiation pattern for the DTU-ESA VAST-12 antenna. The on-ground calibration of the MIRAS space radiometer for ESA's SMOS mission was carried out at the DTU-ESA facility...

  9. Electrical conductivity measurements on silicate melts using the loop technique

    Science.gov (United States)

    Waff, H. S.

    1976-01-01

    A new method is described for measurement of the electrical conductivity of silicate melts under controlled oxygen partial pressure at temperatures to 1550 C. The melt samples are suspended as droplets on platinum-rhodium loops, minimizing iron loss from the melt due to alloying with platinum, and providing maximum surface exposure of the melt to the oxygen-buffering gas atmosphere. The latter provides extremely rapid equilibration of the melt with the imposed oxygen partial pressure. The loop technique involves a minimum of setup time and cost, provides reproducible results to within + or - 5% and is well suited to electrical conductivity studies on silicate melts containing redox cations.

  10. Comparison of bone density measurement techniques: DXA and Archimedes' principle.

    Science.gov (United States)

    Keenan, M J; Hegsted, M; Jones, K L; Delany, J P; Kime, J C; Melancon, L E; Tulley, R T; Hong, K D

    1997-11-01

    The standard method for determination of density (g/cm3) of bones from small animals has been the application of Archimedes' principle. A recent development has been software for the determination of "density" (g/cm2) of small animal bones with dual-energy X-ray absorptiometry (DXA). We compared Archimedes' principle and DXA (Hologic QDR-2000) in the measurement of the densities of whole and hollowed femurs of 5- to 6-month-old retired female breeder rats. In an attempt to ensure detectable treatment differences, rats were used from a low-vitamin D Holtzman and a supplemental-vitamin D Sprague-Dawley colony. Whole femur densities were higher for supplemental-vitamin D colony rats than for low vitamin D rats using both techniques (Archimedes' principle, p Archimedes' principle than for DXA. Other variables such as femur ash weight and calcium content were also highly correlated to densities with both techniques. Hollowed femur density values were higher than whole femur values with Archimedes' principle but lower with DXA. Colony effects for hollowed femur densities were diminished with Archimedes' principle (p < 0.03) and eliminated with DXA (p < 0.53). Investigation of whole bones is more biologically relevant, and both techniques were effective in detecting differences between whole femurs from low-vitamin D and supplemental-vitamin D colony rats.

  11. Diagnostic techniques for measuring suprathermal electron dynamics in plasmas (invited).

    Science.gov (United States)

    Coda, S

    2008-10-01

    Plasmas, both in the laboratory and in space, are often not in thermodynamic equilibrium, and the plasma electron distribution function is accordingly non-Maxwellian. Suprathermal electron tails can be generated by external drives, such as rf waves and electric fields, or internal ones, such as instabilities and magnetic reconnection. The variety and importance of the phenomena in which suprathermal electrons play a significant role explains an enduring interest in diagnostic techniques to investigate their properties and dynamics. X-ray bremsstrahlung emission has been studied in hot magnetized plasmas for well over two decades, flanked progressively by electron-cyclotron emission in geometries favoring the high-energy end of the distribution function (high-field-side, vertical, oblique emission), by electron-cyclotron absorption, by spectroscopic techniques, and at lower temperatures, by Langmuir probes and electrostatic analyzers. Continuous progress in detector technology and in measurement and analysis techniques, increasingly sophisticated layouts (multichannel and tomographic systems, imaging geometries), and highly controlled suprathermal generation methods (e.g., perturbative rf modulation) have all been brought to bear in recent years on an increasingly detailed, although far from complete, understanding of suprathermal electron dynamics.

  12. Flowing dusty plasma experiments: Generation of flow and measurement techniques

    CERN Document Server

    Jaiswal, S; Sen, A

    2016-01-01

    A variety of experimental techniques for the generation of subsonic/supersonic dust fluid flows and means of measuring such flow velocities are presented. The experiments have been carried out in a $\\Pi-$shaped Dusty Plasma Experimental (DPEx) device with micron size kaolin/Melamine Formaldehyde (MF) particles embedded in a background of Argon plasma created by a direct current (DC) glow discharge. A stationary dust cloud is formed over the cathode region by precisely balancing the pumping speed and gas flow rate. A flow of dust particles/fluid is generated by additional gas injection from a single or dual locations or by altering the dust confining potential. The flow velocity is then estimated by three different techniques, namely, by super Particle Identification (sPIT) code, Particle Image Velocimetry (PIV) analysis and the excitation of Dust Acoustic Waves (DAWs). The results obtained from these three different techniques along with their merits and demerits are discussed. An estimation of the neutral dr...

  13. Improved technique for blood flow velocity measurement using Doppler effect

    Science.gov (United States)

    Valadares Oliveira, Eduardo J.; Nantes Button, Vera L. d. S.; Maia, Joaquim M.; Costa, Eduardo T.

    2002-04-01

    The Doppler velocimeter developed allows to determine the angle between the ultrasonic beam and the velocity vector of the flow, and to calculate the precise blood flow in a vessel. Four piezoelectric transducers constitute the Doppler velocimeter. Three of these transducers are positioned to form an equilateral triangle (base of a pyramid). When these transducers move simultaneously, backward or forward from the initial position, the emitted ultrasonic beams focalize on a position (peak of the pyramid) closer or farther from the transducers faces, according to the depth of the vessel where we intend to measure de flow. The angle between the transducers allows adjusting the height of this pyramid and the position of the focus (where the three beams meet). A forth transducer is used to determine the diameter of the vessel and monitor the position of the Doppler velocimeter relative to the vessel. Simulation results showed that with this technique is possible to accomplish precise measurement of blood flow.

  14. Comparisons between different techniques for measuring mass segregation

    CERN Document Server

    Parker, Richard J

    2015-01-01

    We examine the performance of four different methods which are used to measure mass segregation in star-forming regions: the radial variation of the mass function $\\mathcal{M}_{\\rm MF}$; the minimum spanning tree-based $\\Lambda_{\\rm MSR}$ method; the local surface density $\\Sigma_{\\rm LDR}$ method; and the $\\Omega_{\\rm GSR}$ technique, which isolates groups of stars and determines whether the most massive star in each group is more centrally concentrated than the average star. All four methods have been proposed in the literature as techniques for quantifying mass segregation, yet they routinely produce contradictory results as they do not all measure the same thing. We apply each method to synthetic star-forming regions to determine when and why they have shortcomings. When a star-forming region is smooth and centrally concentrated, all four methods correctly identify mass segregation when it is present. However, if the region is spatially substructured, the $\\Omega_{\\rm GSR}$ method fails because it arbitra...

  15. Atmospheric flow measurements using the PIV and HWA techniques

    Directory of Open Access Journals (Sweden)

    Luciana Bassi Marinho Pires

    2010-08-01

    Full Text Available Alcântara Space Center (ASC is the Brazilian gate to the space where rockets of different sizes are launched. At ASC there is a relative topographical variation, coastal cliff, which modifies the atmospheric boundary layer characteristics and can cause interference for operations of rockets. In the present work, a simplified model (mock-up was studied in a wind tunnel. A scale factor of 1:1000 was used and the atmospheric flow was measured using the hot wire anemometer (HWA and particle image velocimetry (PIV techniques. Using of HWA it was possible to calculate values of average wind speed and fluctuations in a set of points of the section of tests that representing the region of the ASC. Through these measures, other meteorological parameters that represent the atmospheric flow, such as the friction velocity (u*, the roughness length (z0 from the logarithmic profile and the alpha exponent (ɑ of the power law were calculated. With the use of the PIV´s technique, the streamlines and the vorticity fields were obtained and it was noticed that the vorticity generated downwind of the coastal cliff has a strong turbulence (vorticities around 2000 sˉ¹. A rectangular building (simulating the mobile integration tower was inserted at the mock-up and the downwind turbulence was similar to the one generated by the coastal cliff.

  16. Atmospheric NO2 concentration measurements using differential absorption lidar technique

    Science.gov (United States)

    Devara, P. C. S.; Raj, P. Ernest

    1992-02-01

    Using the Differential Absorption Lidar (DIAL) technique, two types of approaches, namely, reflection from retroreflector / topographic target and backscatter from atmosphere, are available for studying remotely the atmospheric NO2 concentration. The Argon ion lidar system at the Indian Institute of Tropical Meteorology (IITM), Pune, India has been used for the measurements by following both the path-averaged and range-resolved approaches. For the former, a topographic target (hill) is used for determining path-averaged surface concentration. In the latter, spectral properties of atmospheric attenuation is used for making range-resolved measurements in the surface layer. The results of the observations collected by following both approaches are presented. The average surface NO2 concentration was found to vary between 0.01 and 0.105 ppm and the range-resolved measurements exhibited higher values suggesting treatment of the lidar data for scattering and extinction effects due to atmospheric aerosols and air molecules, and atmospheric turbulence. Certain modifications that are suggested to the experimental set-up, data acquisition and analysis to improve the measurements are briefly described.

  17. Nonlinear ultrasonic measurements based on cross-correlation filtering techniques

    Science.gov (United States)

    Yee, Andrew; Stewart, Dylan; Bunget, Gheorghe; Kramer, Patrick; Farinholt, Kevin; Friedersdorf, Fritz; Pepi, Marc; Ghoshal, Anindya

    2017-02-01

    Cyclic loading of mechanical components promotes the formation of dislocation dipoles in metals, which can serve as precursors to crack nucleation and ultimately lead to failure. In the laboratory setting, an acoustic nonlinearity parameter has been assessed as an effective indicator for characterizing the progression of fatigue damage precursors. However, the need to use monochromatic waves of medium-to-high acoustic energy has presented a constraint, making it problematic for use in field applications. This paper presents a potential approach for field measurement of acoustic nonlinearity by using general purpose ultrasonic pulser-receivers. Nonlinear ultrasonic measurements during fatigue testing were analyzed by the using contact and immersion pulse-through method. A novel cross-correlation filtering technique was developed to extract the fundamental and higher harmonic waves from the signals. As in the case of the classic harmonic generation, the nonlinearity parameters of the second and third harmonics indicate a strong correlation with fatigue cycles. Consideration was given to potential nonlinearities in the measurement system, and tests have confirmed that measured second harmonic signals exhibit a linear dependence on the input signal strength, further affirming the conclusion that this parameter relates to damage precursor formation from cyclic loading.

  18. Rainbow technique for multi-parameter measurement of absorbing cylinder

    Institute of Scientific and Technical Information of China (English)

    Feihu Song; Chuanlong Xu; Shimin Wang

    2013-01-01

    Rainbow refractometry is widely used to measure the radius and real part of refractive index of a cylinder.However,studies on the detection of imaginary part of the refractive index with rainbow technique were scarce.This paper presents a new method for simultaneously measuring the radius,real and imaginary part of the refractive index of a cylinder,on the basis of the Airy theory and the Bouguer theory.The rainbows produced by the illuminated cylinder at a capillary exit are captured by a CCD camera in a labscale system,and then processed by the proposed method.Experimental results showed that the radius,real and imaginary part of the refractive index can be accurately determined when the SNR (signal to noise ratio) of the ripple structure is sufficiently high.However,the SNR of the ripple structure gradually decreases with decreasing scattering intensity of the cylinder,leading to larger measurement errors of the radius and real part of the refractive index.The relative error of the imaginary part of the refractive index derived from the measurement errors of the radius and real part of the refractive index,is less than 3.4%.

  19. Physical Properties of Liquid Terbium Measured by Levitation Techniques

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To understand the nature and behavior of rare earth metals in their liquid phases, accurate values of their physical properties are essential.However, to measure their physical properties, the samples should be maintained in liquid phases for prolonged time, and this raises a formidable challenge.This is mainly explained by their high melting temperatures (e.g., 1629 K for Tb), high vapor pressure, and the risk of melt contamination with a crucible or support.An electrostatic levitation furnace alleviated these difficulties and allowed the determination of density, surface tension, and viscosity of several metals above their melting temperature.Here, first, the levitation furnace facility and the noncontact diagnostic procedures were briefly discussed, followed by the explanation of their thermophysical property measurements over wide temperature ranges.The density was obtained using an ultraviolet-based imaging technique that allowed excellent illumination, even at elevated temperatures.Over the 1615 to 1880 K temperature span, the density measurements could be expressed as ρ(T)=7.84×103-0.47 (T-Tm) (kg·m-3) with Tm=1629 K, yielding a volume expansion coefficient α(T) =6.0×10-5 (K-1).In addition, the surface tension and the viscosity could be determined by inducing a drop oscillation to a molten sample.Using this technique, the surface tension data could be expressed as σ(T)=8.93×102-0.10 (T-Tm)(mN·m-1) and those for viscosity as η(T) =0.583 exp [4.1×104/(RT)] (MPa·s) over the 1690 to 1980 K temperature range.

  20. Method and System for Measuring Spinning YarnTension Using Image Measuring Technique

    Institute of Scientific and Technical Information of China (English)

    梅顺齐; 宋志峰; 张智明

    2004-01-01

    A non-contact method and system for measuring spinning yarn tension is developed using an image processing technique and based on the theory of yarn balloon dynamics. The theoretical basis of the measurement is the relationship among yarn tension, balloon shape, and spinning parameters. The yarn tension is determined according to the geometric parameters of the balloon, which are measured from an image of the balloon. The digital image is captured with a CCD sensor, and processed in a computer using a wavelet transform technique. A measuring system is developed, and experiments are carried out. The results show that the proposed non-contact method is effective in the on-line measurement of spinning yarn tension for improving the degree of automation of the spinning machine.

  1. Intelligent instruments for process measurement techniques (monitoring of sensors)

    Science.gov (United States)

    Bauer, B.; Hess, H. D.; Kalinski, J. R.; Leisenberg, W.; Marsch, D.

    1984-06-01

    Possibilities to extract redundant information of temperature sensors (resistance thermometers, thermocouples, semiconductor temperature sensors), and to find out which of the suggested redundancies are most suited for self controlled monitoring were investigated. Practical experience with equipment for process measurement techniques shows that sensor failures are five times more frequent than electronic malfunction. For resistance thermometers the measured values of the redundant information source (ac resistance) are too small (relative inductivity change 7 million). The information sources strain gage and propagation of ultrasonic waves are excluded because of physical properties in the sensor materials. Changes in the crystalline structure of thermocouples have the effect that there is no well defined relationship between thermoelectric voltage and the redundant information sources, resistance and coupled current impulses. A correlation of thermovoltage with these redundant values would yield a measurement uncertainty corresponding to more than + or - 50 K. Experiments with negative temperature coefficient sensors show that a failure is proceeded by a change in capacitance of the order of 0.1 pF.

  2. A laser speckle imaging technique for measuring tissue perfusion.

    Science.gov (United States)

    Forrester, Kevin R; Tulip, J; Leonard, C; Stewart, C; Bray, Robert C

    2004-11-01

    Laser Doppler imaging (LDI) has become a standard method for optical measurement of tissue perfusion, but is limited by low resolution and long measurement times. We have developed an analysis technique based on a laser speckle imaging method that generates rapid, high-resolution perfusion images. We have called it laser speckle perfusion imaging (LSPI). This paper investigates LSPI output and compares it to LDI using blood flow models designed to simulate human skin at various levels of pigmentation. Results show that LSPI parameters can be chosen such that the instrumentation exhibits a similar response to changes in red blood cell concentration (0.1%-5%, 200 microL/min) and velocity (0-800 microL/min, 1% concentration) and, given its higher resolution and quicker response time, could provide a significant advantage over LDI for some applications. Differences were observed in the LDI and LSPI response to tissue optical properties. LDI perfusion values increased with increasing tissue absorption, while LSPI perfusion values showed a slight decrease. This dependence is predictable, owing to the perfusion algorithms specific to each instrument, and, if properly compensated for, should not influence each instrument's ability to measure relative changes in tissue perfusion.

  3. An appraisal of techniques and equipment for cutting force measurement

    Institute of Scientific and Technical Information of China (English)

    AUDY J.

    2006-01-01

    Current research focussed on the assessment of metal machining process parameters and on the development of adaptive control, shows that machine performance, work-piece and tool material selections, tool life, quality of machined surfaces,the geometry of cutting tool edges, and cutting conditions are closely related to the cutting forces. This information is of great interest to cutting tool manufactures and users alike. Over the years there have been significant developments and improvements in the equipment used to monitor such forces. In 1930 mechanical gauges were replaced by resistance strain gauges, and some 30 years later compact air gauge dynamometers were invented. Since this time intensive research has continued being directed towards developing new approaches to cutting force measurement. The Kistler Company, well-known manufacturer of acceleration and piezoelectrical dynamometers, has worked in this field for more than three decades, and developed very sensitive devices.While leading manufacturing research laboratories are often equipped with this technology, classical electrical strain gauges and other dynamometers of individual designs are still commonly used in industry. The present paper presents data obtained using different techniques of force measurement in metal machining processes. In particular, areas of uncertainties, illustrated through results concerning the turning process, are analysed, leading to an appraisal of the current status of these measurements and their significance.

  4. Measuring verbal psychotherapeutic techniques – A systematic review of intervention characteristics and measures

    Directory of Open Access Journals (Sweden)

    Antje eGumz

    2015-11-01

    Full Text Available Language is one of the most important tools of psychotherapists. The working mechanisms of verbal therapeutic techniques, however, are still marginally understood. In part, this is due to the lack of a generally acknowledged typology as well as a gold standard for the assess-ment of verbal techniques, which limits the possibility of conducting studies focusing this topic. The present study reviews measures used in clinical research which assess directly ob-servable dimensions of verbal interventions in a reliable manner. All measures were evaluated with respect to their theoretical foundation, research goals, assessment modes, and various psychometric properties. A systematic search in databases (PubMed, PsycInfo, PsycArticles, PSYNDEX, Web of Science, Embase followed by an additional snowballing search cover-ing the years 1940-2013 yielded n=179 publications eligible for review. Within these publica-tions, 34 measures were identified showing great heterogeneity regarding the aspects under study. Only two measures reached the highest psychometric standards and can be recom-mended for clinical use without any reservation. Central problems include deficiencies in the systematization of techniques as well as their partly ambiguous and inconsistent definitions. To promote this field of research, it will be important to achieve a consensus concerning the terminology, conceptions and measures of verbal techniques.

  5. Recent advances in automation, robotics and measuring techniques

    CERN Document Server

    Zieliński, Cezary; Kaliczyńska, Małgorzata

    2014-01-01

    This book presents the recent advances and developments in control, automation, robotics, and measuring techniques. It presents contributions of top experts in the fields, focused on both theory and industrial practice. The particular chapters present a deep analysis of a specific technical problem which is in general followed by a numerical analysis and simulation, and results of an implementation for the solution of a real world problem. The book presents the results of the International Conference AUTOMATION 2014 held 26 - 28 March, 2014 in Warsaw, Poland on Automation – Innovations and Future Prospectives The presented theoretical results, practical solutions and guidelines will be useful for both researchers working in the area of engineering sciences and for practitioners solving industrial problems.

  6. Blood pressure measurement in hemodialysis: The importance of the measurement technique.

    Science.gov (United States)

    Kubrusly, M; de Oliveira, Claudia Maria Costa; Silva, R P; Pinheiro, M A; Rocha, M B C; Magalhães, R M

    2016-03-01

    Systemic arterial hypertension contributes to the high cardiovascular morbidity in hemodialysis (HD) patients, but the accuracy of blood pressure (BP) measurement in this population has not been well studied. To evaluate the agreement between BP measurement using the routine measurement technique (usual method) and the technique recommended by the VII Joint (standard method). This cross-sectional study enrolled 124 patients in a single center who had undergone dialysis for more than three months and were 18 years of age or older. The BP was verified at the start of dialysis by the nursing team (usual method) and by the researchers (standard method). The agreement between the systolic and diastolic BP (SBP and DBP) measurements was tested by the Bland-Altman analysis. A difference in BP measurement higher than ±5 mm Hg was considered clinically significant. The studied group had a mean age of 53.2 years. The average difference between routine and standard BP measurement was -6 mm Hg for SBP (limits of agreement: -40.1-28 mm Hg; P measured by both methods was observed in 69.4% of the patients for SBP and in 61.3% for DBP. The disagreement between the results of different BP measurement methods in HD patients was significant and the BP was underestimated using the usual BP method. BP measurement standardization should be encouraged to avoid errors in diagnosis and therapy.

  7. A new technique for the solution of references problem in oil pollution measurement by UVF technique

    Directory of Open Access Journals (Sweden)

    Kasım Cemal Güven

    2016-09-01

    Full Text Available In this work, the problems of references used for oil pollution measurement by UVF method were discussed. The main problem of this method is that the origin of the reference for pollutant oil is unknown. The proposed solution for this problem was based on sea water sample which was taken from contaminated area, extracted by DCM, the organic phase was distilled, its calibration curve was plotted with this residue oil and measurement was made on its equation. The oil pollution results for the sea water of K0 station by using this equation for 2013 was 15.21 mg/L and for 2014 15.25 mg/L. for the same samples determination of oil pollution by using crude oil references varies between 0.11 and 1.15 various crude oils and using chrysene reference 0.11-0.19 mg/L. These results show that pollution level varied depending on references used. The proposed method more realistically determines the oil pollution level. The proposed technique is the first for oil pollution measurement by UVF.

  8. Techniques for measuring ammonia in fly ash, mortar, and concrete

    Energy Technology Data Exchange (ETDEWEB)

    Rathbone, R.F. [Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Reseach; Majors, R.K. [Boral Material Technologies, Inc., San Antonio, TX (United States). Engineered Materials

    2003-12-01

    The presence of ammonia in fly ash that is to be used in mortar and concrete is of increasing concern in the U.S., mainly due to the installation of selective catalytic reduction (SCR) DeNOx systems. When the SCR catalyst is new, contamination of the fly ash with ammonia is generally not a concern. However, as the catalyst in the SCR ages and becomes less efficient, the ammonia slip increases and results in a greater amount of ammonium salt being precipitated on the fly ash. The increase in ammonia concentration is compounded by variability that can occur on a day-to-day basis. When marketing ammonia-laden fly ash for use in mortar and concrete it is imperative that the concentration of ammonia is known. However, there currently is no widely accepted or ''standard'' method for ammonia measurement in fly ash. This paper describes two methods that have been developed and used by the University of Kentucky Center for Applied Energy Research and Boral Material Technologies, Inc. One of the methods uses gas detection tubes and can provide an accurate determination within five to ten minutes. Thus it is suitable as a rapid field technique. The other method employs a gas-sensing electrode and requires a longer period of time to complete the measurement. However, this second method can also be used to determine the quantity of ammonia in fresh mortar and concrete. (orig.)

  9. Trace element measurement in Saliva by NAA and PIXE techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hamidian, M.R.; Vahid Golpayegani, M.; Shojai, S. (Shahid Beheshti Medical Science Univ., Shemiran, Tehran (Iran, Islamic Republic of))

    1993-01-01

    The activity of salivary glands and the chemical and physical properties of saliva, especially in some illnesses in which the activity of salivary glands and the chemical and physical properties alter, sometimes have severe effects on sedimentation and tooth decay. Long-standing investigations have shown the relationship between salivary gland activity and saliva composition in dental carries. Many modern techniques have been employed to measure important elements in saliva. The major elements in saliva include sodium, potassium, calcium, magnesium, chlorine, phosphorus, iodine, and fluorine. It should be pointed out that the amount of minerals changes when the diet changes. The major constituent of saliva is water with a density of 1.007 g/cm[sup 3] in which 0.6% is solid, 0.3% organic material and 0.3% inorganic material. In addition to other effects, the acidity (pH) of saliva has a strong effect on tooth sedimentation. Type of work, degree of stress, and mental condition affect salivary gland activity. When the acidity of salivary fluid in the mouth and consequently over the teeth drops, sedimentation increases. In this paper, the results of trace element measurement in saliva are presented.

  10. A review of hemorheology: Measuring techniques and recent advances

    Science.gov (United States)

    Sousa, Patrícia C.; Pinho, Fernando T.; Alves, Manuel A.; Oliveira, Mónica S. N.

    2016-02-01

    Significant progress has been made over the years on the topic of hemorheology, not only in terms of the development of more accurate and sophisticated techniques, but also in terms of understanding the phenomena associated with blood components, their interactions and impact upon blood properties. The rheological properties of blood are strongly dependent on the interactions and mechanical properties of red blood cells, and a variation of these properties can bring further insight into the human health state and can be an important parameter in clinical diagnosis. In this article, we provide both a reference for hemorheological research and a resource regarding the fundamental concepts in hemorheology. This review is aimed at those starting in the field of hemodynamics, where blood rheology plays a significant role, but also at those in search of the most up-to-date findings (both qualitative and quantitative) in hemorheological measurements and novel techniques used in this context, including technical advances under more extreme conditions such as in large amplitude oscillatory shear flow or under extensional flow, which impose large deformations comparable to those found in the microcirculatory system and in diseased vessels. Given the impressive rate of increase in the available knowledge on blood flow, this review is also intended to identify areas where current knowledge is still incomplete, and which have the potential for new, exciting and useful research. We also discuss the most important parameters that can lead to an alteration of blood rheology, and which as a consequence can have a significant impact on the normal physiological behavior of blood.

  11. Broadband Lidar Technique for Precision CO2 Measurement

    Science.gov (United States)

    Heaps, William S.

    2008-01-01

    Presented are preliminary experimental results, sensitivity measurements and discuss our new CO2 lidar system under development. The system is employing an erbium-doped fiber amplifier (EDFA), superluminescent light emitting diode (SLED) as a source and our previously developed Fabry-Perot interferometer subsystem as a detector part. Global measurement of carbon dioxide column with the aim of discovering and quantifying unknown sources and sinks has been a high priority for the last decade. The goal of Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission is to significantly enhance the understanding of the role of CO2 in the global carbon cycle. The National Academy of Sciences recommended in its decadal survey that NASA put in orbit a CO2 lidar to satisfy this long standing need. Existing passive sensors suffer from two shortcomings. Their measurement precision can be compromised by the path length uncertainties arising from scattering within the atmosphere. Also passive sensors using sunlight cannot observe the column at night. Both of these difficulties can be ameliorated by lidar techniques. Lidar systems present their own set of problems however. Temperature changes in the atmosphere alter the cross section for individual CO2 absorption features while the different atmospheric pressures encountered passing through the atmosphere broaden the absorption lines. Currently proposed lidars require multiple lasers operating at multiple wavelengths simultaneously in order to untangle these effects. The current goal is to develop an ultra precise, inexpensive new lidar system for precise column measurements of CO2 changes in the lower atmosphere that uses a Fabry-Perot interferometer based system as the detector portion of the instrument and replaces the narrow band laser commonly used in lidars with the newly available high power SLED as the source. This approach reduces the number of individual lasers used in the system from three or more

  12. Diagnostic performance of MRI measurements to assess hindfoot malalignment. An assessment of four measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Florian M.; Hoffmann, Adrienne; Mamisch-Saupe, Nadja; Hodler, Juerg [University Hospital Balgrist and University of Zurich, Radiology, Zuerich (Switzerland); Farshad, Mazda; Espinosa, Norman [University Hospital Balgrist and University of Zurich, Department of Orthopaedic Surgery, Zuerich (Switzerland); Resnick, Donald [University of California San Diego, Department of Radiology, San Diego, CA (United States)

    2013-09-15

    To investigate the ability of coronal non-weight-bearing MR images to discriminate between normal and abnormal hindfoot alignment. Three different measurement techniques (calcaneal axis, medial/lateral calcaneal contour) based on weight-bearing hindfoot alignment radiographs were applied in 49 patients (mean, 48 years; range 21-76 years). Three groups of subjects were enrolled: (1) normal hindfoot alignment (0 -10 valgus); (2) abnormal valgus (>10 ); (3) any degree of varus hindfoot alignment. Hindfoot alignment was then measured on coronal MR images using four different measurement techniques (calcaneal axis, medial/lateral calcaneal contour, sustentaculum tangent). ROC analysis was performed to find the MR measurement with the greatest sensitivity and specificity for discrimination between normal and abnormal hindfoot alignment. The most accurate measurement on MR images to detect abnormal hindfoot valgus was the one using the medial calcaneal contour, reaching a sensitivity/specificity of 86 %/75 % using a cutoff value of >11 valgus. The most accurate measurement on MR images to detect abnormal hindfoot varus was the sustentaculum tangent, reaching a sensitivity/specificity of 91 %/71 % using a cutoff value of <12 valgus. It is possible to suspect abnormal hindfoot alignment on coronal non-weight-bearing MR images. (orig.)

  13. Analytic technique measures aromatics in soil and water

    Energy Technology Data Exchange (ETDEWEB)

    Roy, K.A.

    1990-12-01

    This paper reports on a technique for detecting aromatic compounds in soil and water. The technique traces its roots to a chemical reaction discovered in 1877. The reaction is an organic synthesis process that has been harnessed for the production of high-octane gasoline, synthetic rubber, plastics and synthetic detergents. More than a century later the same chemistry is used as the basis for an analytical technique that quantifies contamination caused by products.

  14. A new bridge technique for neutron tomography and diffraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burca, G., E-mail: G.Burca@open.ac.uk [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); James, J.A. [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); Kockelmann, W. [ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, OX11 0QX (United Kingdom); Fitzpatrick, M.E. [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); Zhang, S.Y. [ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, OX11 0QX (United Kingdom); Hovind, J. [Paul Scherrer Institute (PSI), CH-5232, Villigen (Switzerland); Langh, R. van [Delft University of Technology, Department of Materials Science, Faculty 3mE, Mekelweg 2, 2628 CD Delft (Netherlands); Rijksmuseum Amsterdam, P.O. Box 74888, 1070 DN Amsterdam (Netherlands)

    2011-09-21

    An attractive feature of neutron techniques is the ability to identify hidden materials and structures inside engineering components and objects of art and archaeology. Bearing this in mind we are investigating a new technique, 'Tomography Driven Diffraction' (TDD), that exploits tomography data to guide diffraction experiments on samples with complex structures and shapes. The technique can be used utilising combinations of individual tomography and diffraction instruments, such as NEUTRA (PSI, CH) and ENGIN-X (ISIS, UK), but is also suitable for new combined imaging and diffraction instruments such as the JEEP synchrotron engineering instrument (DIAMOND, UK) and the proposed IMAT neutron imaging and diffraction instrument (ISIS, UK).

  15. High-temperature strain measurement techniques: Current developments and challenges

    Science.gov (United States)

    Lemcoe, M. M.

    1992-01-01

    Since 1987, a very substantial amount of R&D has been conducted in an attempt to develop reliable strain sensors for the measurements of structural strains during ground testing and hypersonic flight, at temperatures up to at least 2000 deg F. Much of the effort has been focused on requirements of the NASP Program. This presentation is limited to the current sensor development work and characterization studies carried out within that program. It is basically an assessment as to where we are now and what remains to be done in the way of technical accomplishments to meet the technical challenges posed by the requirements and constraints established for the NASP Program. The approach for meeting those requirements and constraints has been multi-disciplinary in nature. It was recognized early on that no one sensor could meet all these requirements and constraints, largely because of the large temperature range (cryogenic to at least 2000 deg F) and many other factors, including the most challenging requirement that the sensor system be capable of obtaining valid 'first cycle data'. Present candidate alloys for resistance-type strain gages include Fe-Cr-Al and Pd-Cr. Although they have superior properties regarding withstanding very high temperatures, they exhibit large apparent strains that must either be accounted for or cancelled out by various techniques, including the use of a dual-element, half-bridge dummy gage, or electrical compensation networks. A significant effort is being devoted to developing, refining, and evaluating the effectiveness of those techniques over a broad range in temperature and time. In the quest to obtain first-cycle data, ways must be found to eliminate the need to prestabilize or precondition the strain gage, before it is attached to the test article. It should be noted that present NASP constraints do not permit prestabilization of the sensor, in situ. Gages are currently being 'heat treated' during manufacture in both the wire- and foil

  16. Blood flow rate measurements with indicator techniques revisited

    DEFF Research Database (Denmark)

    Sejrsen, Per; Bülow, Jens

    2009-01-01

    In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions......, necessary precautions for the application of these experimental techniques are emphasized. Special attention has been carried out to elucidate the consequence of a choice of indicators having a large distribution volume in the tissues....

  17. WD-XRA technique in multiphase flow measuring

    Energy Technology Data Exchange (ETDEWEB)

    Gogolev, A.S.; Cherepennikov, Yu.M.; Vukolov, A.V. [Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Rezaev, R.O. [Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Nuclear University MEPhI, Kashirskoye Shosse 31, Moscow 115409 (Russian Federation); Stuchebrov, S.G. [Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Hampai, D. [INFN Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Dabagov, S.B. [INFN Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Nuclear University MEPhI, Kashirskoye Shosse 31, Moscow 115409 (Russian Federation); RAS P.N. Lebedev Physical Institute, Lenin Avenue 53, Moscow 119991 (Russian Federation); Liedl, A.; Polese, C. [INFN Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy)

    2015-07-15

    A new technique to perform the analysis of multiphase fluid flow based on wave dispersive X-ray absorptiometry is suggested. The numerical simulation and comparison of this technique with currently used approaches are provided and a way to increase the luminosity intensity is found that includes the usage the X-ray focusing optics by a bent crystal and a polycapillary semilens. Based on numerical simulation of radiation spectrum the influence of the bent crystal on the luminosity is evaluated and experimentally shown the advantages of using the multicapillary optics.

  18. WD-XRA technique in multiphase flow measuring

    Science.gov (United States)

    Gogolev, A. S.; Cherepennikov, Yu. M.; Vukolov, A. V.; Rezaev, R. O.; Stuchebrov, S. G.; Hampai, D.; Dabagov, S. B.; Liedl, A.; Polese, C.

    2015-07-01

    A new technique to perform the analysis of multiphase fluid flow based on wave dispersive X-ray absorptiometry is suggested. The numerical simulation and comparison of this technique with currently used approaches are provided and a way to increase the luminosity intensity is found that includes the usage the X-ray focusing optics by a bent crystal and a polycapillary semilens. Based on numerical simulation of radiation spectrum the influence of the bent crystal on the luminosity is evaluated and experimentally shown the advantages of using the multicapillary optics.

  19. Subpixel Target Location Techniques for 3-D Coordinate Measuring System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The close photogrammetric 3-D coordinate measurement is a new measuring technology in the fields of the coordinate measurement machine (CMM) in recent years. In this method, we usually place some targets on the measured object and take image of targets to determine the object coordinate. The subpixel location of target image plays an important role in high accuracy 3-D coordinate measuring procedure. In this paper, some subpixel location methods are reviewed and some factors which affect location precision are analyzed. Then we propose bilinear interpolation centroid algorithm. The experiments have shown this algorithm can improve accuracy of target centroid by increasing available pixels.

  20. Web Usage Statistics: Measurement Issues and Analytical Techniques.

    Science.gov (United States)

    Bertot, John Carlo; McClure, Charles R.; Moen, William E.; Rubin, Jeffrey

    1997-01-01

    One means of Web use evaluation is through analysis of server-generated log files. Various log file analysis techniques and issues are presented that are related to the interpretation of log file data. Study findings indicate a number of problems; recommendations and areas needing further research are outlined. (AEF)

  1. Full-field laser vibration measurement in NDT techniques

    Science.gov (United States)

    Yue, Kaiduan; Li, Zhongke; Yi, Yaxing; Zhang, Fei

    2008-12-01

    Research of Non Destructive Testing (NDT) methodology has developed rapidly in recent years[1][2]. But it is rarely used for small objects such as Micro-electronic Mechanics System. Due to the small size of the MEMS, the traditional method of contact measurement seriously affects the parameter of the object measured. So a high accuracy non-contact measurement is required for optimization of MEMS designs and improvement of its reliability[3][4]. With recent advances in photonics, electronics, and computer technology, a Non Destructive Testing (NDT) laser time average interferometry is proposed in the paper. Laser interferometry has the advantages of non-contact, high accuracy, full-field and fast speed, so it can be used to detect cracks in MEMS. A time average measurement method of digital speckle pattern interferometry is proposed to measure the vibration mode of the MEMS in the paper. According to the sudden change of amplitude of vibration mode, a crack can be measured. With the speckle average technology, high accuracy phase-shift, continuous phase scanning technology, combined with optical amplification technology, the resolution of the amplitude reaches 1nm, and the resolution of the crack reaches 5μm. The measurement system being full-field, the measuring speed of the measurement system can reach 512*512 points per one minute.

  2. Characterization of small antennas for hearing aids by several measurement techniques

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Zhang, Jiaying; Khatun, Afroza;

    2010-01-01

    Characteristics of electrically small loop antennas were measured by different techniques and the results were compared in-between. The techniques employed were: a single-probe spherical near-field technique, a multi-probe spherical near-field technique, a reverberation chamber, and a Wheeler cap...

  3. A Technique for Measuring the Solubilities of Gases in Liquids

    Science.gov (United States)

    1990-12-01

    measured using a mercury manometer referenced to vacuum. To begin the experiment, a pure, dry gas is injected quickly into the system by opening valve...Tbath Vx - v - V 2 - V 3Apfinal Tm where Pb - ambient pressure (mmHg). The ambient pressure is measured using a mercury manometer and the ambient

  4. Children with smoking parents have a higher airway resistance measured by the interruption technique

    NARCIS (Netherlands)

    Kooi, EMW; Vrijlandt, Elianne J.L.E.; Boezen, HM; Duiverman, EJ

    2004-01-01

    Children exposed to environmental tobacco smoke, during or after pregnancy, are known to have decreased lung function. So far this has been measured using spirometry in schoolchildren and invasive techniques in newborns. The interruption technique (Rint) is a noninvasive technique to measure airway

  5. Hyperpolarized 3He apparent diffusion coefficient MRI of the lung: reproducibility and volume dependency in healthy volunteers and patients with emphysema

    DEFF Research Database (Denmark)

    Diaz, S.; Casselbrant, I.; Piitulainen, E.;

    2008-01-01

    PURPOSE: To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency. MATERIALS AND METHODS: A total of eight healthy volunteers and 16...... days was good in both healthy volunteers and patients (SD range of 0.003-0.013 cm(2)/second and 0.001-0.009 cm(2)/second at 6% and 15% of TLC for healthy volunteers, and a SD range of 0.001-0.041 cm(2)/second and 0.001-0.011 cm(2)/second, respectively, for patients). A minor but significant increase...... in mean ADC with increased inhaled gas volume was observed in both groups. CONCLUSION: Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights...

  6. The advance and development of damage measurement technique of rock

    Institute of Scientific and Technical Information of China (English)

    YANG Geng-she(杨更社)

    2003-01-01

    The key problem of rock damage mechanics is that determination of the variable of rock damage and the establishment of damage constitutive relation of rock, which is inevitable involved in the measurement problem of rock. In this paper, the measurement technology and method of rock damage are comprehensively narrated, analyzed and studied. On the basis of the narrating the former study, a new method (Computerized Tomography,CT for short) is introduced, which is applied to rock damage measurement. On the other hand, some newest study results and laws in the field are also introduced, which are from some scholars, the author of this paper.

  7. Correlation techniques and measurements of wave-height statistics

    Science.gov (United States)

    Guthart, H.; Taylor, W. C.; Graf, K. A.; Douglas, D. G.

    1972-01-01

    Statistical measurements of wave height fluctuations have been made in a wind wave tank. The power spectral density function of temporal wave height fluctuations evidenced second-harmonic components and an f to the minus 5th power law decay beyond the second harmonic. The observations of second harmonic effects agreed very well with a theoretical prediction. From the wave statistics, surface drift currents were inferred and compared to experimental measurements with satisfactory agreement. Measurements were made of the two dimensional correlation coefficient at 15 deg increments in angle with respect to the wind vector. An estimate of the two-dimensional spatial power spectral density function was also made.

  8. Measuring techniques for autogenous strain of cement paste

    DEFF Research Database (Denmark)

    Lura, Pietro; Jensen, Ole Mejlhede

    2006-01-01

    Volumetric measurement of autogenous strain is frequently performed by placing the fresh cement paste in a rubber membrane submerged in water. The volume change of the cement paste is measured by the amount of water displaced by the submerged sample. Volumetric and linear measurements of autogenous...... of the volumetric method. Water absorption is driven by a lowering of the water activity in the cement paste due to dissolved salts in the pore fluid and to self-desiccation. From the moment of casting, significant water uptake was registered in all experiments. This water uptake influenced the volumetric...... on the same cement pastes....

  9. Measuring techniques for autogenous strain of cement paste

    DEFF Research Database (Denmark)

    Lura, Pietro; Jensen, Ole Mejlhede

    2007-01-01

    Volumetric measurement of autogenous strain is frequently performed by placing the fresh cement paste in a rubber membrane submerged in water. The volume change of the cement paste is measured by the amount of water displaced by the submerged sample. Volumetric and linear measurements of autogenous...... of the volumetric method. Water absorption is driven by a lowering of the water activity in the cement paste due to dissolved salts in the pore fluid and to self-desiccation. From the moment of casting, significant water uptake was registered in all experiments. This water uptake influenced the volumetric...... on the same cement pastes....

  10. Measurements of dimensional accuracy using linear and scanning profile techniques.

    Science.gov (United States)

    Harrison, A; Huggett, R; Zissis, A

    1992-01-01

    Various measurement methods have been described for the determination of dimensional accuracy and stability of denture base materials. This investigation introduces a computerised coordinate measuring machine (CCMM) and compares it with two methods routinely used for assessment of the accuracy of fit of denture base materials. The results demonstrate that the three methods (digital calipers, optical comparator, and CCMM) are acceptable for linear measurement. The CCMM was also used in its scanning mode to define and to quantify the contour changes of the resin bases. The advantages of the CCMM become apparent when two-dimensional changes require assessment.

  11. Apt strain measurement technique for impulsive loading applications

    Science.gov (United States)

    Ranjan Nanda, Soumya; Kulkarni, Vinayak; Sahoo, Niranjan

    2017-03-01

    The necessity of precise measurement of strain time history for impulsive loading applications has been addressed in the present investigation. Finite element modeling is initially carried out for a hemispherical test model and stress bar assembly to arrive at an appropriate location for strain measurement. In dynamic calibration experiments, strain measurements are performed using two wire and three wire quarter bride arrangements along with half bridge circuit. Usefulness of these arrangements has been verified by analyzing strain signals in time and frequency domains. Comparison of recovered force time histories proved that the half bridge circuit is the most suitable for such applications. Actual shock tube testing of the instrumented hemispherical test model confirmed the applicability of half bridge circuit for short duration strain measurements.

  12. Advances in bioanalytical techniques to measure steroid hormones in serum.

    Science.gov (United States)

    French, Deborah

    2016-06-01

    Steroid hormones are measured clinically to determine if a patient has a pathological process occurring in the adrenal gland, or other hormone responsive organs. They are very similar in structure making them analytically challenging to measure. Additionally, these hormones have vast concentration differences in human serum adding to the measurement complexity. GC-MS was the gold standard methodology used to measure steroid hormones clinically, followed by radioimmunoassay, but that was replaced by immunoassay due to ease of use. LC-MS/MS has now become a popular alternative owing to simplified sample preparation than for GC-MS and increased specificity and sensitivity over immunoassay. This review will discuss these methodologies and some new developments that could simplify and improve steroid hormone analysis in serum.

  13. Auroral ionospheric and thermospheric measurements using the incoherent scatter technique

    Energy Technology Data Exchange (ETDEWEB)

    Kofman, W. (CEPHAG, St. Martin (France))

    1992-11-01

    The incoherent scatter technique has been applied since 1965 to study the ionosphere and thermosphere in different regions of the Earth. The analysis of the received signal gives access to several ionospheric parameters as a function of height: electron density, electron and ion temperatures and ion velocity. The derivation of these parameters is usually a complicated mathematical procedure that requires a non-linear regression program. A lot of research has been done in the ionospheric and atmospheric science using this technique. In this paper we describe how one derives the ion-neutral collision frequency and the ion composition parameters. It is usually difficult to retrieve these parameters with the incoherent scatter technique; as a result, in the standard data analysis procedure, an ionospheric model is used instead. However the numerical values chosen in the model have an influence on the other derived parameters. For instance the choice of a wrong ion composition leads to erroneous plasma temperatures. It is therefore important to assess by how much the standard procedure deviates from reality. For this reason we compare the ion composition and collision frequency retrieved from a sophisticated analysis scheme with the values that are derived from models under similar geophysical conditions. It is also possible to derive from the observed ionospheric parameters the neutral concentrations, temperatures and winds, by using the energy and momentum equations for the ions and the neutrals. In this paper the different methods and the corresponding assumptions involved in the data analysis are discussed. We describe the influence of the frictional heating, of the vertical neutral wind and of the ionospheric perturbations on the derivation of the neutral atmospheric parameters. Our discussion of the processes involved are drawn from results obtained by Chatanika, Sondrestrom and EISCAT radars.

  14. [The research advance of measuring techniques on corneoscleral constitutive parameters].

    Science.gov (United States)

    Bao, Fangjun; Deng, Manli; Wang, Qinmei

    2015-11-01

    The occurrence and development of myopia and keratoconus is closely related to the changes of scleral and corneal biomechanical properties. The accurate measurement of biomechanical properties for corneoscleral tissure is very important on diagnosis of eye diseases, improvement of ocular operation, ocular biological parameter measurement and invention of ophthalmic instrument. Corneoscleral tissue, composed of bundles of compact and staggered collagen fiber and extracellular matrix, constitute the outer surface of the eyeball. The inhomogeneous distribution of the diameter, gap and amount of collagen fiber, makes its biomechanical characteristics really complex, characterized by nonlinear, viscoelastic, anisotropic, regional variation and age-related variation and etc. With the development of medical diagnostic technology, the importance of the ocular biomechanical property measurement is increasingly recognized. Nevertheless, measuring technology on ocular biomechanics properties are still not well understood by the majority of ophthalmologists. In order to facilitate the researchers to select a suitable measuring platform and method, the development of international corneoscleral biomechanical propertiy measuring technology was reviewed in this article.

  15. Continuous measurement of cardiac output using stochastic system identification techniques.

    Science.gov (United States)

    Yelderman, Mark

    2004-01-01

    Indicator dilutions techniques offer the most reliable methods of determining clinical cardiac output because of the elastic nature of the cardiac vessels. A catheter-mounted beating filament affords a simple means of supplying "heat" indicator, but is power and temperature limited because of possible patient injury. A stochastic signal processing method using pseudorandom binary infusion of heat offers a process of enhancing the signal to noise sufficiently to facilitate a computation of cardiac output over a reasonable time period (5 min) with a clinically acceptable error.

  16. A reevaluation of the interrupter technique for airway resistance measurement

    Science.gov (United States)

    Jackson, A. C.; Milhorn, H. T., Jr.; Norman, J. R.

    1974-01-01

    An attempt was made to obtain a better insight into the actual transient response of airway opening pressure (Pao) following rapid occlusion. With this knowledge it was hoped to be able to clarify the reason for the overestimations found by other investigators, and possibly to obtain a more accurate method of estimating alveolar pressure just prior to interruption. This would result in an improved method for estimating airway resistance. Use of an extrapolation method was found to provide an improved correlation between resistances determined by the interruptor technique and those found by the plethysmograph in normal subjects.

  17. A Review of Techniques to Measure Protein Sorption to Soft Contact Lenses.

    Science.gov (United States)

    Hall, Brad; Forrest, James A; Jones, Lyndon

    2017-09-01

    To compare and critically evaluate a variety of techniques to measure the quantity and biological activity of protein sorption to contact lenses over short time periods. A literature review was undertaken investigating the major techniques to measure protein sorption to soft contact lens materials, with specific reference to measuring protein directly on lenses using in situ, ex situ, protein structural, and biological activity techniques. The use of in situ techniques to measure protein quantity provides excellent sensitivity, but many are not directly applicable to contact lenses. Many ex situ techniques struggle to measure all sorbed proteins, and these measurements can have significant signal interference from the lens materials themselves. Techniques measuring the secondary and tertiary structures of sorbed proteins have exhibited only limited success. There are a wide variety of techniques to measure both the amount of protein and the biological activity of protein sorbed to soft contact lens materials. To measure the mass of protein sorbed to soft contact lenses (not just thin films) over short time periods, the method of choice should be I radiolabeling. This technique is sensitive enough to measure small amounts of deposited protein, provided steps are taken to limit and measure any interaction of the iodine tracer with the materials. To measure the protein activity over short time periods, the method of choice should be to measure the biological function of sorbed proteins. This may require new methods or adaptations of existing ones.

  18. Review of measurement techniques for the neutron radiative-capture process

    Energy Technology Data Exchange (ETDEWEB)

    Poenitz, W.P.

    1981-07-01

    The experimental techniques applied in measurements of the neutron capture process are reviewed. The emphasis is on measurement techniques used in neutron capture cross section measurements. The activation technique applied mainly in earlier work has still its use in some cases, specifically for measurements of technologically important cross sections (/sup 238/U and /sup 232/Th) with high accuracy. Three major prompt neutron radioactive capture detection techniques have evolved: the total gamma radiation energy detection technique (mainly with large liquid scintillation detectors), the gamma-energy proportional detectors (with proportional counters or Moxon-Rae detectors), and the pulse-height weighting technique. These measurement techniques are generally applicable, however, shortcomings limit the achievable accuracy to a approx. = 5 to 15% uncertainty level.

  19. Measurement of particle size based on digital imaging technique

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong; TANG Hong-wu; LIU Yun; WANG Hao; LIU Gui-ping

    2013-01-01

    To improve the analysis methods for the measurement of the sediment particle sizes with a wide distribution and of irregular shapes,a sediment particle image measurement,an analysis system,and an extraction algorithm of the optimal threshold based on the gray histogram peak values are proposed.Recording the pixels of the sediment particles by labeling them,the algorithm can effectively separate the sediment particle images from the background images using the equivalent pixel circles with the same diameters to represent the sediment particles.Compared with the laser analyzer for the case of blue plastic sands,the measurement results of the system are shown to be reasonably similar.The errors are mainly due to the small size of the particles and the limitation of the apparatus.The measurement accuracy can be improved by increasing the Charge-Coupled Devices (CCD) camera resolution.The analysis method of the sediment particle images can provide a technical support for the rapid measurement of the sediment particle size and its distribution.

  20. Comparison of transepithelial resistance measurement techniques: Chopsticks vs. Endohm.

    Science.gov (United States)

    Sheller, Rebecca A; Cuevas, Maria E; Todd, Maria C

    2017-01-01

    TER measurements across confluent cellular monolayers provide a useful indication of TJ strength between epithelial and endothelial cells in culture. Having a reliable and accurate method of measuring cell-to-cell adhesion is critical to studies in pathophysiology and cancer metastasis. However, the use of different technical approaches to measure TER has reportedly yielded inconsistent measurements within the same cell lines. In the current study, we compared the peak TER values for the MDCK (canine kidney) and MCF-7 (human breast cancer) epithelial cell lines using two common approaches (Chopstick and Endohm) and two types of polymer inserts (PC and PET). Both cell lines demonstrated a statistically significant difference in the peak TERs obtained using the two different approaches. Further, the MDCK (but not the MCF-7) cells demonstrated a statistically significant difference between the peak TERs when using the same approach but different inserts. Our study indicates the importance of using a single approach when seeking to measure and compare the TER values of cultured cell lines.

  1. Method of pectus excavatum measurement based on structured light technique

    Science.gov (United States)

    Glinkowski, Wojciech; Sitnik, Robert; Witkowski, Marcin; Kocoń, Hanna; Bolewicki, Pawel; Górecki, Andrzej

    2009-07-01

    We present an automatic method for assessment of pectus excavatum severity based on an optical 3-D markerless shape measurement. A four-directional measurement system based on a structured light projection method is built to capture the shape of the body surface of the patients. The system setup is described and typical measurement parameters are given. The automated data analysis path is explained. Their main steps are: normalization of trunk model orientation, cutting the model into slices, analysis of each slice shape, selecting the proper slice for the assessment of pectus excavatum of the patient, and calculating its shape parameter. We develop a new shape parameter (I3ds) that shows high correlation with the computed tomography (CT) Haller index widely used for assessment of pectus excavatum. Clinical results and the evaluation of developed indexes are presented.

  2. A digital coincidence measurement system using FPGA techniques

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Fengming; Hsieh, S.C.; Yen, W.W. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, 30043, Taiwan (China); Chou, H.P., E-mail: hpc@ess.nthu.edu.tw [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, 30043, Taiwan (China)

    2011-10-01

    A field programmable gate array (FPGA) based digital coincidence system has been developed to use with NaI scintillators for field applications. The analog output signal from the photomultiplier anode is directly transferred into digital signals by pulse height for pulse width conversion. The digital signal contains the energy and timing information of the radiation events. The pulse width is then measured by a vernier type of time-to-digital converter (TDC). The timing information of radiation events is recorded and analyzed by a coincidence unit. Both the TDC unit and the coincidence unit are implemented using a commercial available FPGA board. The measured data is then sent to a personal computer for spectrum display. Efficiency as well as energy calibration has been performed. The system showed a timing resolution about 13 ns and an energy resolution of 12% for 0.511 MeV annihilation gammas; it also successfully demonstrated the background rejection ability through coincidence measurement.

  3. Method of pectus excavatum measurement based on structured light technique.

    Science.gov (United States)

    Glinkowski, Wojciech; Sitnik, Robert; Witkowski, Marcin; Kocoń, Hanna; Bolewicki, Pawel; Górecki, Andrzej

    2009-01-01

    We present an automatic method for assessment of pectus excavatum severity based on an optical 3-D markerless shape measurement. A four-directional measurement system based on a structured light projection method is built to capture the shape of the body surface of the patients. The system setup is described and typical measurement parameters are given. The automated data analysis path is explained. Their main steps are: normalization of trunk model orientation, cutting the model into slices, analysis of each slice shape, selecting the proper slice for the assessment of pectus excavatum of the patient, and calculating its shape parameter. We develop a new shape parameter (I(3ds)) that shows high correlation with the computed tomography (CT) Haller index widely used for assessment of pectus excavatum. Clinical results and the evaluation of developed indexes are presented.

  4. Comparative technique in measurements of Ge detectors effective volumes

    Science.gov (United States)

    Demidova, E. V.; Kirpichnikov, I. V.; Vasenko, A. A.

    1999-01-01

    A simple and quick procedure was proposed for measurements of large coaxial Ge detectors effective volumes. It included a comparison of background spectra collected with several detectors without any shielding in an underground laboratory. Such measurements were performed in Homestake (USA) and Canfranc (Spain) laboratories with several 1 kg and 2 kg detectors. Monte-Carlo calculations confirmed that ratios of numbers of events in continua of the spectra should be either equal or very close to the ratios of the detectors effective volumes.

  5. Impedance technique for measuring dielectrophoretic collection of microbiological particles

    CERN Document Server

    Allsopp, D W E; Brown, A P; Betts, W B

    1999-01-01

    Measurement of the impedance change resulting from the collection of microbiological particles at coplanar electrodes is shown to be an effective and potentially quantitative method of detecting dielectrophoresis. Strong correlations between the frequency-dependent dielectrophoretic collection characteristics measured by impedance change and those observed using an established counting method based on image analysis have been obtained for Escherichia coli. In addition it is shown that the new electrical method can be used to sense dielectrophoretic collection of 19 nm diameter latex beads, particles too small to be resolved by conventional optical detection systems. (author)

  6. Calibration Techniques for Accurate Measurements by Underwater Camera Systems

    Directory of Open Access Journals (Sweden)

    Mark Shortis

    2015-12-01

    Full Text Available Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems.

  7. Calibration Techniques for Accurate Measurements by Underwater Camera Systems.

    Science.gov (United States)

    Shortis, Mark

    2015-12-07

    Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems.

  8. A new technique for measurements of the urethra pressure profile.

    Science.gov (United States)

    Asmussen, M; Ulmsten, U

    1976-01-01

    A new standardized technique for continuous recording of the urethral pressure profile simultaneously with intravesical pressure has been developed. The pressures were recorded using two micr-transducers enclosed in a thin Dacron catheter. The catheter moved with a constant speed through the urethra with the aid of a specially designed instrument. This instrument is described. Twenty-five healthy women were examined. The patients were divided into two groups: (A) 10 postmenopausal women, and (B) 15 fertile women. The results of the recordings showed that the functional length and the absolute length of the urethra could be reproduced with an error of less than 1 mm. The maximal pressure amplitude was significantly less in group A.

  9. Technique for measuring speed and visual motion sensitivity in lizards

    Directory of Open Access Journals (Sweden)

    Darren Burke

    2008-01-01

    Full Text Available Testing sensory characteristics on herpetological species has been difficult due to a range of properties related to physiology, responsiveness, performance ability, and the type of reinforcer used. Using the Jacky lizard as a model, we outline a successfully established procedure in which to test the visual sensitivity to motion characteristics. We incorporated modifications to traditional operant paradigms by using three video playback systems to deliver random-dot kinematogram motion stimuli coupled with salient computer-animated secondary reinforcers representative of biologically important appetitive stimuli. This procedure has the capacity to test other visual aspects in lizards as well as other nonhuman species using video playback and computer-animation techniques as experimental tools.

  10. MEASURING THE LEANNESS OF SUPPLIERS USING PRINCIPAL COMPONENT ANALYSIS TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Y. Zare Mehrjerdi

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: A technique that helps management to reduce costs and improve quality is ‘lean supply chain management’, which focuses on the elimination of all wastes in every stage of the supply chain and is derived from ‘agile production’. This research aims to assess and rank the suppliers in an auto industry, based upon the concept of ‘production leanness’. The focus of this research is on the suppliers of a company called Touse-Omron Naein. We have examined the literature about leanness, and classified its criteria into ten dimensions and 76 factors. A questionnaire was used to collect the data, and the suppliers were ranked using the principal component analysis (PCA technique.

    AFRIKAANSE OPSOMMING: Lenige voorsieningsbestuur (“lean supply chain management” is ’n tegniek wat bestuur in staat stel om koste te verminder en gehalte te verbeter. Dit fokus op die vermindering van vermorsing op elke stadium van die voorsieningsketting en word afgelei van ratse vervaardiging (“agile production”. Hierdie navorsing poog om leweransiers in ’n motorbedryf te beoordeel aan die hand van die konsep van vervaardigingslenigheid (“production leanness”. Die navorsing fokus op leweransiers van ’n maatskappy genaamd Touse-Omron Naein. ’n Literatuurstudie aangaande lenigheid het gelei tot die klassifikasie van kriteria in tien dimensies en 76 faktore. ’n Vraelys is gebruik om die data te versamel en die leweransiers is in rangvolgorde geplaas aan die hand van die PCA-tegniek.

  11. Measuring the Readability of Elementary Algebra Using the Cloze Technique.

    Science.gov (United States)

    Kulm, Gerald

    The relationship to readability of ten variables characterizing structural properties of mathematical prose was investigated in elementary algebra textbooks. Readability was measured by algebra student's responses to two forms of cloze tests. Linear and currilinear correlations were calculated between each structural variable and the cloze test.…

  12. Measuring Student Growth: Techniques and Procedures for Occupational Education.

    Science.gov (United States)

    Erickson, Richard C.; Wentling, Tim L.

    Designed for current and future occupational instructors, counselors, and administrators, the comprehensive measurement text is directed toward all subject areas in occupational education--industrial, business/distributive, home economics, agriculture, health occupations, and personal/public services. It offers necessary guidelines to select,…

  13. An MSc Course Module: Wind Turbine Measurement Techniques

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Pedersen, Knud Ole Helgesen

    2005-01-01

    The 2-year MSc in Wind power engineering at the Technical University of Denmark comprises modules from core engineering teaching and from other modules specifically designed to the MSc. This Note outlines the content of such a specific module on the subject of wind turbine measurement. The lectures...

  14. Corruption in Higher Education: Conceptual Approaches and Measurement Techniques

    Science.gov (United States)

    Osipian, Ararat L.

    2007-01-01

    Corruption is a complex and multifaceted phenomenon. Forms of corruption are multiple. Measuring corruption is necessary not only for getting ideas about the scale and scope of the problem, but for making simple comparisons between the countries and conducting comparative analysis of corruption. While the total impact of corruption is indeed…

  15. A simple technique for a.c. conductivity measurements

    Indian Academy of Sciences (India)

    R Padma Suvarna; K Raghavendra Rao; K Subbarangaiah

    2002-12-01

    An inexpensive, indigenous and a simple electronic instrument based on voltage follower, current–to–voltage converter, zero crossing detector and a phase detector has been developed for measurement of a.c. conductivity. Real and imaginary parts of complex impedance are determined for a given sample as a function of frequency and the given sample is represented by a pure electronic model.

  16. A numerical technique to design blast noise mitigation measures

    NARCIS (Netherlands)

    Berg, F. van den; Eerden, F.J.M. van der

    2007-01-01

    Large weapons, such as armor, artillery or demolitions, create a high-energy blast wave. It has a low frequency content, typically between 15 and 125 Hz, and can propagate over large distances. As a result it is a relative important cause for annoyance. Mitigation measures need to be close to the so

  17. Cerebral blood oxygenation measurements in neonates with optoacoustic technique

    Science.gov (United States)

    Herrmann, Stephen; Petrov, Irene Y.; Petrov, Yuriy; Richardson, C. Joan; Fonseca, Rafael A.; Prough, Donald S.; Esenaliev, Rinat O.

    2017-03-01

    Cerebral hypoxia is a major contributor to neonatal/infant mortality and morbidity including severe neurological complications such as mental retardation, cerebral palsy, motor impairment, and epilepsy. Currently, no technology is capable of accurate monitoring of neonatal cerebral oxygenation. We proposed to use optoacoustics for this application by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, optical parametric oscillator (OPO) and laser diode optoacoustic systems for measurement of SSS blood oxygenation in the reflection mode through open anterior or posterior fontanelles and in the transmission mode through the skull in the occipital area. In this paper we present results of initial tests of the laser diode system for neonatal cerebral oxygenation measurements. First, the system was tested in phantoms simulating neonatal SSS. Then, using the data obtained in the phantoms, we optimized the system's hardware and software and tested it in neonates admitted in the Neonatal Intensive Care Unit. The laser diode system was capable of detecting SSS signals in the reflection mode through the open anterior and posterior fontanelles as well as in the transmission mode through the skull with high signal-to-noise ratio. Using the signals measured at different wavelengths and algorithms developed for oxygenation measurements, the laser diode system provided real-time, continuous oxygenation monitoring with high precision at all these locations.

  18. A numerical technique to design blast noise mitigation measures

    NARCIS (Netherlands)

    Berg, F. van den; Eerden, F.J.M. van der

    2007-01-01

    Large weapons, such as armor, artillery or demolitions, create a high-energy blast wave. It has a low frequency content, typically between 15 and 125 Hz, and can propagate over large distances. As a result it is a relative important cause for annoyance. Mitigation measures need to be close to the

  19. A Free-Space Measurement Technique of Terahertz Dielectric Properties

    Science.gov (United States)

    Zhang, Xiansheng; Chang, Tianying; Cui, Hong-Liang; Sun, Zhonglin; Yang, Chuanfa; Yang, Xiuwei; Liu, Lingyu; Fan, Wei

    2017-03-01

    The free-space method for material dielectric characterization in the microwave band is extended to terahertz frequencies. By analyzing the advantages and disadvantages of the relative permittivity of the transmission/reflection method for non-magnetic materials, a fast calculation method using a transmission-only method is proposed. Based on the convergence analysis of the algorithm, a method to estimate the initial value is also proposed. Finally, through measurements of the permittivity of high-density polyethylene, polystyrene, polypropylene, and polymethyl methacrylate in the 325-500 GHz band, we verify the rationality of the algorithm and demonstrate its applicability. Through the combination of the two methods, the terahertz dielectric properties of a majority of flat non-conducting solid materials and non-polar liquid materials can be measured.

  20. Novel technique to measure the polarizability of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Yevetska, Olena; Richter, Achim; Schrieder, Gerhard; Watzlawik, Steffen [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); Ahrens, Juergen [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, Mainz (Germany); Chizhov, Vladimir; Iatsioura, Valeriy; Maev, Evgeniy; Orishchin, Evgeniy; Petrov, Gennadiy; Sergeev, Lev; Smirenin, Yuriy [Petersburg Nuclear Physics Institute, Petersburg (Russian Federation)

    2008-07-01

    At the Superconducting Darmstadt electron linear accelerator S-DALINAC an experiment has been built to measure the electric and magnetic polarizability of the proton and the deuteron by low energy Compton scattering with the aim to determine the energy dependence of the differential cross sections of elastic {gamma}p/{gamma}d scattering at two angles in a model-independent way in the photon energy range 20-100 MeV with a precision < 1%. A narrow collimated bremsstrahlung photon beam enters two high pressure ionisation chambers filled with hydrogen, which act as target as well as detector gas. Two large volume NaI-spectrometers detect the Compton scattered photons under angles of 90 and 130 and serve as triggers for coincidence measurements of the recoiling nucleons in the chambers. First experiments were carried out using electron beams of 60 and 79 MeV, respectively. Results based on pulse shape analysis are presented.

  1. Optical Measurement Techniques for Optical Fiber and Waveguide Devices

    Institute of Scientific and Technical Information of China (English)

    D.Y.; Kim; Y.; Park; N.H.; Seong; Y.C.Youk; J.Y.; Lee; S.; Moon; I.H.; Shin; H.S.; Ryu

    2003-01-01

    We describe three major optical characterization methods for fiber and fiber devices. A simple servo controlled scanning fiber-optic confocal microscope is proposed for determining the refractive index profile of an optical fiber. To measure the chromatic dispersion of a short length fiber a Mach-Zehnder fiber interferometer with a novel interferometric distance meter is introduced. At the end, a tomographic method is demonstrated for determining the 2-D stress profile of a fiber.

  2. Measuring 35S of Aerosol Sulfate: Techniques and First Results

    Science.gov (United States)

    Brothers, L. A.; Dominguez, G.; Bluen, B.; Corbin, A.; Abramian, A.; Thiemens, M. H.

    2007-12-01

    On a global and regional level, the cycling of sulfur in the environment has consequences for air quality, human health, and may contribute to global climate change. Due to its multiple oxidation states, the sulfur cycle is very complex and poorly understood. Stable isotopes are currently used to understand reaction pathways as well as sources and sinks of sulfurous compounds in the environment. Sulfur also has one short lived (τ1/2 ~87 d) radioactive isotope (35S) which is continuously made in the atmosphere by the cosmic ray spallation of argon, is then quickly oxidized to 35SO2 and enters the atmospheric sulfur cycle. The short-lived radioactive nature of this isotope of sulfur provides us with potentially powerful tracer for understanding the time scales at which sulfur is oxidized, deposited, and transported in the atmosphere and the deposition of atmospheric sulfate into rivers and water catchments. However, despite its potential, the use of 35S as a tracer of aerosol chemistry has not been fully exploited, Here we present details of instrumental set up for measuring 35S in aerosol sulfate and some preliminary results of measurements of 35S abundances in aerosols from Riverside (inland) and La Jolla (coastal) CA and discuss the sensitivity and limitations of the measurements in providing insights into day/night aerosol chemistry (Riverside) as well as the uptake of SO2 pollution in coastal environments by sea-salt aerosols. Also, we present preliminary results from measurement of sulfate in river water in Ecuador before and after precipitation events.

  3. A Survey of Advanced Microwave Frequency Measurement Techniques

    OpenAIRE

    Anand Swaroop Khare,

    2012-01-01

    Microwaves are radio waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. The science of photonics includes the generation, emission, modulation, signal processing, switching, transmission, amplification, detection and sensing of light. Microwave photonics has been introduced for achieving ultra broadband signal processing. Instantaneous Frequency Measurement (IFM) receivers play an important ro...

  4. Technique for Performing Dielectric Property Measurements at Microwave Frequencies

    Science.gov (United States)

    Barmatz, Martin B.; Jackson, Henry W.

    2010-01-01

    A paper discusses the need to perform accurate dielectric property measurements on larger sized samples, particularly liquids at microwave frequencies. These types of measurements cannot be obtained using conventional cavity perturbation methods, particularly for liquids or powdered or granulated solids that require a surrounding container. To solve this problem, a model has been developed for the resonant frequency and quality factor of a cylindrical microwave cavity containing concentric cylindrical samples. This model can then be inverted to obtain the real and imaginary dielectric constants of the material of interest. This approach is based on using exact solutions to Maxwell s equations for the resonant properties of a cylindrical microwave cavity and also using the effective electrical conductivity of the cavity walls that is estimated from the measured empty cavity quality factor. This new approach calculates the complex resonant frequency and associated electromagnetic fields for a cylindrical microwave cavity with lossy walls that is loaded with concentric, axially aligned, lossy dielectric cylindrical samples. In this approach, the calculated complex resonant frequency, consisting of real and imaginary parts, is related to the experimentally measured quantities. Because this approach uses Maxwell's equations to determine the perturbed electromagnetic fields in the cavity with the material(s) inserted, one can calculate the expected wall losses using the fields for the loaded cavity rather than just depending on the value of the fields obtained from the empty cavity quality factor. These additional calculations provide a more accurate determination of the complex dielectric constant of the material being studied. The improved approach will be particularly important when working with larger samples or samples with larger dielectric constants that will further perturb the cavity electromagnetic fields. Also, this approach enables the ability to have a

  5. Probing Radiation Damage in Plutonium Alloys with Multiple Measurement Techniques

    Energy Technology Data Exchange (ETDEWEB)

    McCall, S K; Fluss, M J; Chung, B W

    2010-04-21

    A material subjected to radiation damage will usually experience changes in its physical properties. Measuring these changes in the physical properties provides a basis to study radiation damage in a material which is important for a variety of real world applications from reactor materials to semiconducting devices. When investigating radiation damage, the relative sensitivity of any given property can vary considerably based on the concentration and type of damage present as well as external parameters such as the temperature and starting material composition. By measuring multiple physical properties, these differing sensitivities can be leveraged to provide greater insight into the different aspects of radiation damage accumulation, thereby providing a broader understanding of the mechanisms involved. In this report, self-damage from {alpha}-particle decay in Pu is investigated by measuring two different properties: magnetic susceptibility and resistivity. The results suggest that while the first annealing stage obeys second order chemical kinetics, the primary mechanism is not the recombination of vacancy-interstitial close pairs.

  6. A surface wave elastography technique for measuring tissue viscoelastic properties.

    Science.gov (United States)

    Zhang, Xiaoming

    2017-04-01

    A surface wave elastography method is proposed to study the viscoelastic properties of skin by measuring the surface wave speed and attenuation on the skin. Experiments were carried out on porcine skin tissues. The surface wave speed is measured by the change of phase with distance. The wave attenuation is measured by the decay of wave amplitude with distance. The change of viscoelastic properties with temperature was studied at room and body temperatures. The wave speed was 1.83m/s at 22°C but reduced to 1.52m/s at 33°C. The viscoelastic ratio was almost constant from 22°C to 33°C. Fresh and decayed tissues were studied. The wave speed of the decayed tissue increased from 1.83m/s of fresh state to 2.73m/s. The viscoelastic ratio was 0.412/mm at the decayed state compared to 0.215/mm at the fresh state. More tissue samples are needed to study these viscoelastic parameters according to specific applications.

  7. Limitations caused by distortion in room impulse response measurements by swept sine technique

    DEFF Research Database (Denmark)

    Stojic, Branko; Ciric, Dejan; Markovic, Milos

    2011-01-01

    by the distortion in room impulse response measurements by swept sine technique are analyzed here by the simulations and measurements. For the investigation, both linear and exponential swept sines are used as an excitation signal. In the simulations, this signal is modified by the nonlinearity model in the time...... of a measured response can be limited in a similar way as in maximum length sequence technique, although the saturation level (maximum dynamic range) is higher for swept sine technique. Thus, swept sine technique is also vulnerable to a certain extent to distortion that limits the quality of measured impulse...

  8. Measurement of pharyngeal sensory cortical processing: technique and physiologic implications

    Directory of Open Access Journals (Sweden)

    Ringelstein E Bernd

    2009-07-01

    Full Text Available Abstract Background Dysphagia is a major complication of different diseases affecting both the central and peripheral nervous system. Pharyngeal sensory impairment is one of the main features of neurogenic dysphagia. Therefore an objective technique to examine the cortical processing of pharyngeal sensory input would be a helpful diagnostic tool in this context. We developed a simple paradigm to perform pneumatic stimulation to both sides of the pharyngeal wall. Whole-head MEG was employed to study changes in cortical activation during this pharyngeal stimulation in nine healthy subjects. Data were analyzed by means of synthetic aperture magnetometry (SAM and the group analysis of individual SAM data was performed using a permutation test. Results Our results revealed bilateral activation of the caudolateral primary somatosensory cortex following sensory pharyngeal stimulation with a slight lateralization to the side of stimulation. Conclusion The method introduced here is simple and easy to perform and might be applicable in the clinical setting. The results are in keeping with previous findings showing bihemispheric involvement in the complex task of sensory pharyngeal processing. They might also explain changes in deglutition after hemispheric strokes. The ipsilaterally lateralized processing is surprising and needs further investigation.

  9. Techniques for Measurement of Nitrate Movement in Soils

    Science.gov (United States)

    Broadbent, F. E.

    1971-01-01

    Contamination of surface and ground waters with nitrate usually involves leaching through soil of nitrate produced by mineralization of soil organic matter, decomposition of animal wastes or plant residues, or derived from fertilizers. Nitrate concentrations in the soil solution may be measured by several chemical procedures or by the nitrate electrode. since nitrate is produced throughout the soil mass it is difficult to identify a source of nitrate contamination by conventional means. This problem can be solved by use of N-15-enriched or N-15-depleted materials as tracers. The latter is particularly attractive because of the negligible possibility of the tracer hazardous to health.

  10. Review of geotechnical measurement techniques for a nuclear waste repository in bedded salt

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    This report presents a description of geotechnical measurement techniques that can provide the data necessary for safe development - i.e., location, design, construction, operation, decommissioning and abandonment - of a radioactive waste repository in bedded salt. Geotechnical data obtained by a diversity of measurement techniques are required during all phases of respository evolution. The techniques discussed in this report are grouped in the following categories: geologic, geophysical and geodetic; rock mechanics; hydrologic, hydrogeologic and water quality; and thermal. The major contribution of the report is the presentation of extensive tables that provide a review of available measurement techniques for each of these categories. The techniques are also discussed in the text to the extent necessary to describe the measurements and associated instruments, and to evaluate the applicability or limitations of the method. More detailed discussions of thermal phenomena, creep laws and geophysical methods are contained in the appendices; references to detailed explanations of measurement techniques and instrumentation are inluded throughout the report.

  11. Measuring Technique of Bubble Size Distributions in Dough

    Science.gov (United States)

    Maeda, Tatsurou; Do, Gab-Soo; Sugiyama, Junichi; Oguchi, Kosei; Tsuta, Mizuki

    A novel technique to recognize bubbles in bread dough and analyze their size distribution was developed by using a Micro-Slicer Image Processing System (MSIPS). Samples were taken from the final stage of the mixing process of bread dough which generally consists of four distinctive stages. Also, to investigate the effect of freeze preservation on the size distribution of bubbles, comparisons were made between fresh dough and the dough that had been freeze preserved at .30°C for three months. Bubbles in the dough samples were identified in the images of MSIPS as defocusing spots due to the difference in focal distance created by vacant spaces. In case of the fresh dough, a total of 910 bubbles were recognized and their maximum diameter ranged from 0.4 to 70.5μm with an average of 11.1μm. On the other hand, a total of 1,195 bubbles were recognized from the freeze-preserved sample, and the maximum diameter ranged from 0.9 to 32.7μm with an average of 6.7μm. Small bubbles with maximum diameters less than 10μm comprised approximately 59% and 78% of total bubbles for fresh and freeze-preserved dough samples, respectively. The results indicated that the bubble size of frozen dough is smaller than that of unfrozen one. The proposed method can provide a novel tool to investigate the effects of mixing and preservation treatments on the size, morphology and distribution of bubbles in bread dough.

  12. Techniques for Galactic Dust Measurements in the Heliosphere

    CERN Document Server

    Grün, E; Horányi, M; Kissel, J; Krüger, H; Srama, R A; Svedhem, H; Withnell, P; Grün, Eberhard; Landgraf, Markus; Horány, Mihaly; Kissel, Jochen; Krüger, Harald; Srama, Ralf; Withnell, Peter

    1999-01-01

    Galactic interstellar dust (ISD) is the major ingredient in planetary formation. However, information on this important material has been extremely limited. Recently the Ulysses dust detector has identified and measured interstellar dust outside 1.8~AU from the Sun at ecliptic latitudes above $50^{\\circ}$. Inside this distance it could not reliably distinguish interstellar from interplanetary dust. Modeling the Ulysses data suggests that up to 30 % of dust flux with masses above $10^{-16}\\rm kg$ at 1~AU is of interstellar origin. From the Hiten satellite in high eccentric orbit about the Earth there are indications that ISD indeed reaches the Earth's orbit. Two new missions carrying dust detectors, Cassini and Stardust, will greatly increase our observational knowledge. In this paper we briefly review instruments used on these missions and compare their capabilities. The Stardust mission [{\\em Brownlee et al.}, 1996] will analyze the local interstellar dust population by an in-situ chemical analyzer and colle...

  13. Malmquist Index, an Alternative Technique for Measuring Credit Institutions Productivity

    Directory of Open Access Journals (Sweden)

    Nicolae Dardac

    2008-03-01

    Full Text Available The present study tackles the banking system’s productivity in a more complex manner, that integrates multiple input, multiple output variables, abdicating from the reductionist perspective of clasical methods, which imposed limits in the number of variables, in the process of productivity measurement and interpretation. The advantage of Malmquist productivity indexes consists both in a quantitative evaluation of the global productivity of a credit institution over a specified period of time, and in the decomposition of productivity, in order to underline how much of its change is due to the catch-up effect, and, respectively, to the implementation of new technologies. The results obtained revealed that credit institutions placed on the first three places in the banking system, according to assets value, maintained constant their productivity level during the analysed period, meanwhile the other institutions in our sample registered a slowly improvement in productivity, determined, mainly, by technological changes.

  14. Exchange Flow Rate Measurement Technique in Density Different Gases

    Directory of Open Access Journals (Sweden)

    Motoo Fumizawa

    2012-04-01

    Full Text Available Buoyancy-driven exchange flows of helium-air through inclined a narrow tube was investigated. Exchange flows may occur following the opening of a window for ventilation, as well as when a pipe ruptures in a high temperature gas-cooled reactor. The experiment in this paper was carried out in a test chamber filled with helium and the flow was visualized using the smoke wire method. A high-speed camera recorded the flow behavior. The image of the flow was transferred to digital data, and the slow flow velocity, i.e. micro flow rate was measured by PIV software. Numerical simulation was carried out by the code of moving particle method with Lagrange method.

  15. Technique for measuring carbon monoxide uptake in mice

    Energy Technology Data Exchange (ETDEWEB)

    Depledge, M.H.; Collis, C.H.; Chir, B.; Barrett, A.

    1981-04-01

    A new method has been developed for measuring carbon monoxide (CO) uptake in mice. Each animal was placed in a syringe and allowed to rebreathe a mixture of CO and helium (He) for 60 s. CO uptake was detemined from a comparison of CO and He concentrations before and after rebreathing. Weight specific CO uptake increased with body weight in CBA mice weighing between 20 to 35 gr. In larger mice, size dependence was less marked, although a slight fall in CO uptake was observed in older animals. Anaesthesia reduced ventilatory rate and CO uptake to a variable extent. The method is reproducible, non-invasive and does not require anaesthesia; consequently, it can be used to study serial changes in lung function. It is sensitive enough to detect lung damage in CBA mice following 16 Gy total body irradiation. Values of diffusing capacity obtained for mice using this method are consistent with published values.

  16. Diffuse scattering measurements with synchrotron radiation: Instrumentation and techniques

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, E.; Georgopoulos, P.

    1985-12-01

    The analysis of diffuse scattering from single crystalline specimens in the reflection mode has generally been acknowledged as a very powerful means of obtaining structural information on local atomic arrangements in disordered alloys, intermetallics and ceramics. However, owing to the low intensities encountered and the large number of measurements required for such an analysis, experiments have been extremely time consuming and few have been attempted. Synchrotron radiation makes it possible to conduct such experiments in a matter of hours and much higher quality data can be obtained than in the laboratory. This paper describes the experimental procedures and methods applied to a study of Al-Cu age hardening alloys conducted at the Cornell Synchrotron Source (CHESS). (orig.).

  17. Optical technique for measurement of random water wave surfaces

    Science.gov (United States)

    Sorrell, F. Y.; Withers, A. L.

    1976-01-01

    An optical system using the refraction of a vertical light ray has been developed for measuring the slope of random wind-generated water waves. The basic elements of the system are photovoltaic cells which are connected to individual amplifiers so that when the refracted light beam is incident on a cell, the output of the cell is amplified and then supplied as input to a comparator. The comparator then provides a specified voltage output, independent of the incident light intensity, as long as it is above a designated background value. The comparators are designed to give output voltages comparable with standard TTL. This arrangement provides a high signal from the cell when it experiences incident light, and a low signal when there is only background light, with the high and low signals at TTL voltage levels.

  18. Extensional bundle waveguide techniques for measuring flow of hot fluids.

    Science.gov (United States)

    Lynnworth, Lawrence C; Liu, Yi; Umina, John A

    2005-04-01

    A bundle of acoustically slender metal rods, each thin compared to wavelength, tightly packed within a sheath, and welded closed at each end, provides a dispersion-free waveguide assembly that acts as a thermal buffer between a transducer and the hot fluid medium the flow of which is to be measured. Gas and steam flow applications have ranged up to 600 degrees C. Liquid applications have ranged from cryogenic (-160 degrees C) to 500 degrees C and include intermittent two-phase flows. The individual rods comprising the bundle usually are approximately one millimeter in diameter. The sheath, made of a pipe or tube, typically has an outside diameter of 12.7 to about 33 mm and usually is about 300 mm long. Materials for the sheath and bundle are selected to satisfy requirements of compatibility with the fluid as well as for acoustic properties. Corrosion-resistant alloys such as 316SS and titanium are commonly used. The buffers are used with transducers that are metal-encapsulated and certified for use in hazardous areas. They operate at a frequency in the range of 0.1 to 1 MHz. The radiating end of the buffer is usually flat and perpendicular to the buffer's main axis. In some cases the end of the buffer is stepped or angled. Angling the radiating faces at approximately 2 degrees to overcome beam drift at Mach 0.1 recently contributed to solving a high-temperature high-velocity flow measurement problem. The temperature in this situation was 300 degrees C, and the gas molecular weight was about 95, with pressure 0.9 to 1.1 bar.

  19. Measurement uncertainty on subsurface defects detection using active infrared thermographic technique

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yoon Jae; Kim [Kongju National University, Cheonan (Korea, Republic of); Choi, Won Jae [Center for Safety Measurements, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2015-10-15

    Active infrared thermography methods have been known to possess good fault detection capabilities for the detection of defects in materials compared to the conventional passive thermal infrared imaging techniques. However, the reliability of the technique has been under scrutiny. This paper proposes the lock-in thermography technique for the detection and estimation of artificial subsurface defect size and depth with uncertainty measurement.

  20. The Lessons of QUANTEC: Recommendations for reporting and gathering data on dose-volume dependencies of treatment outcome

    Science.gov (United States)

    Jackson, Andrew; Marks, Laurence B; Bentzen, Søren M; Eisbruch, Avraham; Yorke, Ellen D; Haken, Randal K Ten; Constine, Louis S; Deasy, Joseph O

    2010-01-01

    The 16 clinical articles in this issue review the dose volume dependence of toxicities of external beam radiotherapy. They are limited by the difficulty of synthesizing results from different publications. The major problems stem from incomplete reporting of results and use of incompatible or ambiguous endpoints. Here we specify these problems, give recommendations to authors, editors, and reviewers on standards of reporting, and, provide methods of defining endpoints suitable for the dose-volume analysis of toxicity. Adopting these recommendations will facilitate meta-analysis and increase the utility of individual studies of the dependence of complications on dose distributions. PMID:20171512

  1. Digital instantaneous frequency measurement technique utilising high-speed ADC’s and FPGA’s

    CSIR Research Space (South Africa)

    Herselman, PL

    2006-02-27

    Full Text Available This paper presents the Digital Instantaneous Frequency Measurement (DIFM) technique, which can measure the carrier frequency of a received waveform within a fraction of a microsecond. The resulting frequency range, resolution and accuracy...

  2. A Novel Technique to Measure Gain Spectrum for Fabry-Pérot Semiconductor Lasers

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel gain measurement technique based on the integration of the measured amplified spontaneous emission spectrum multiplying a phase function over one longitudinal mode interval is proposed for Fabry-Perot semiconductor lasers.

  3. Measurement of Pipe Slope with Laser Scanning Technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D. Y.; Jeon, S. S.; Hong, S. J. [FNC Technology Co., Seoul National University, Seoul (Korea, Republic of); Park, S. C. [Enguard Co., Seoul (Korea, Republic of)

    2011-10-15

    U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01 which provides recommendation and guidance to nuclear power plants for managing gas intrusion and accumulation in safety systems such as Emergency Core Cooling (ECC), Decay Heat Removal (DHR) and Containment Spray (CS) systems. Following the GL2008-01, Nuclear Energy Institute (NEI) reported NEI 09-10 that gives industry guidance for effective prevention and management of system gas accumulation. The location of gas accumulation is usually a high point of piping systems. The high point of system is easily identified by investigating as-built isometric drawings of the subjected systems. However, the real plant piping configuration such as a slope might be different from as-built drawings. If there is a small slope on pipe which is a horizontal configuration in as-built drawing, gas can be accumulated at the high point in pipes with wrong slope as shown in Fig. 1. This paper demonstrates a feasibility to measure the slope of piping systems by using the laser scanning and presents a simple example

  4. The Kety-Schmidt Technique for Quantitative Perfusion and Oxygen Metabolism Measurements in the MR Environment

    Science.gov (United States)

    Lee, John J.; Powers, William J.; Faulkner, Chad B.; Boyle, Patrick J.; Derdeyn, Colin P.

    2013-01-01

    The Kety-Schmidt technique provides quantitative measurement of whole brain cerebral blood flow (CBF). CBF is measured as the area between the arterial and venous washout curves of a diffusible tracer. Oxygen extraction and metabolism may be calculated from arterial and venous samples. In this report we present a method for performing these measurements in an MR environment. This technique could be useful for validation of MR methods of hemodynamic and metabolic measurements in humans. PMID:22997166

  5. Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Adler; L. Dunyushkina; S. Huff; Y. Lu; J. Wilson

    2006-12-31

    The goal of this project was to develop an improved understanding of factors governing performance and degradation of mixed-conducting SOFC cathodes. Two new diagnostic tools were developed to help achieve this goal: (1) microelectrode half-cells for improved isolation of cathode impedance on thin electrolytes, and (2) nonlinear electrochemical impedance spectroscopy (NLEIS), a variant of traditional impedance that allows workers to probe nonlinear rates as a function of frequency. After reporting on the development and efficacy of these tools, this document reports on the use of these and other tools to better understand performance and degradation of cathodes based on the mixed conductor La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} (LSC) on gadolinia or samaria-doped ceria (GDC or SDC). We describe the use of NLEIS to measure O{sub 2} exchange on thin-film LSC electrodes, and show that O{sub 2} exchange is most likely governed by dissociative adsorption. We also describe parametric studies of porous LSC electrodes using impedance and NLEIS. Our results suggest that O{sub 2} exchange and ion transport co-limit performance under most relevant conditions, but it is O{sub 2} exchange that is most sensitive to processing, and subject to the greatest degradation and sample-to-sample variation. We recommend further work that focuses on electrodes of well-defined or characterized geometry, and probes the details of surface structure, composition, and impurities. Parallel work on primarily electronic conductors (LSM) would also be of benefit to developers, and to improved understanding of surface vs. bulk diffusion.

  6. Intercomparison of techniques for the non-invasive measurement of bone mass

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, S.H.

    1981-01-01

    A variety of methods are presently available for the non-invasive measurement of bone mass of both normal individuals and patients with metabolic disorders. Chief among these methods are radiographic techniques such as radiogrammetry, photon absorptiometry, computer tomography, Compton scattering and neutron activation analysis. In this review, the salient features of the bone measurement techniques are discussed along with their accuracy and precision. The advantages and disadvantages of the various techniques for measuring bone mass are summarized. Where possible, intercomparisons are made of the various techniques.

  7. Simple counting technique for measuring mixtures of two pure beta-emitting radionuclides

    CSIR Research Space (South Africa)

    Van Wyngaardt, WM

    2006-08-01

    Full Text Available A simple counting technique to measure mixtures of two pure beta-emitting radionuclides is described. The method is based on elements of two liquid scintillation techniques that are widely used to measure single-radionuclide solutions, namely...

  8. Measuring free metal ion concentrations in multicomponent solutions using Donnan Membrane Technique

    NARCIS (Netherlands)

    Kalis, E.J.J.; Temminghoff, E.J.M.; Weng, L.P.; Riemsdijk, van W.H.

    2007-01-01

    Among speciation techniques that are able to measure free metal ion concentrations, the Donnan membrane technique (DMT) has the advantage that it can measure many different free metal ion concentrations simultaneously in a multicomponent sample. Even though the DMT has been applied to several system

  9. Feasibility of automated dropsize distributions from holographic data using digital image processing techniques. [particle diameter measurement technique

    Science.gov (United States)

    Feinstein, S. P.; Girard, M. A.

    1979-01-01

    An automated technique for measuring particle diameters and their spatial coordinates from holographic reconstructions is being developed. Preliminary tests on actual cold-flow holograms of impinging jets indicate that a suitable discriminant algorithm consists of a Fourier-Gaussian noise filter and a contour thresholding technique. This process identifies circular as well as noncircular objects. The desired objects (in this case, circular or possibly ellipsoidal) are then selected automatically from the above set and stored with their parametric representations. From this data, dropsize distributions as a function of spatial coordinates can be generated and combustion effects due to hardware and/or physical variables studied.

  10. Application of Replica Technique and SEM in Accuracy Measurement of Ceramic Crowns

    Science.gov (United States)

    Trifkovic, B.; Budak, I.; Todorovic, A.; Hodolic, J.; Puskar, T.; Jevremovic, D.; Vukelic, D.

    2012-01-01

    The paper presents a comparative study of the measuring values of the marginal gap related to the ceramic crowns made by dental CAD/CAM system using the replica technique and SEM. The study was conducted using three experimental groups, which consisted of ceramic crowns manufactured by the Cerec CAD/CAM system. The scanning procedure was carried out using three specialized dental 3D digitization systems from the Cerec family - two types of extraoral optical scanning systems and an intraoral optical scanner. Measurements of the marginal gap were carried out using the replica technique and SEM. The comparison of aggregate values of the marginal gap using the replica technique showed a statistically significant difference between the systems. The measured values of marginal gaps of ceramic crowns using the replica technique were significantly lower compared to those measured by SEM. The results indicate that the choice of technique for measuring the accuracy of ceramic crowns influences the final results of investigation.

  11. Comparative study of various techniques for environmental radon, thoron and progeny measurements.

    Science.gov (United States)

    Ramola, R C; Prasad, Mukesh; Rawat, Mukesh; Dangwal, Anoop; Gusain, G S; Mishra, Rosaline; Sahoo, S K; Tokonami, S

    2015-11-01

    Long-term average concentrations of radon, thoron and progeny were measured in normal and high background radiation areas in India using different techniques. Radon, thoron and progeny concentrations were measured using Raduet, Pin-Hole dosimeter, deposition-based CR-39 and deposition-based direct radon/thoron progeny sensor (DRPS/DTPS) detector system. All these techniques were used at a same time inside an individual dwelling. Radon concentration was recorded higher than thoron concentration in Garhwal Homes (NBRA) while thoron concentration was found relatively higher in the houses of Chhatarpur area (HBRA) in Odisha, India. The values measured with the CR-39 detector-based technique were found comparable with the values measured with the LR-115 detector-based technique. The comparisons of results using various techniques and their usefulness in radiation measurements are discussed in detail.

  12. Kalman filtering techniques for reducing variance of digital speckle displacement measurement noise

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ Target dynamics are assumed to be known in measuring digital speckle displacement. Use is made of a simple measurement equation, where measurement noise represents the effect of disturbances introduced in measurement process. From these assumptions, Kalman filter can be designed to reduce variance of measurement noise. An optical and analysis system was set up, by which object motion with constant displacement and constant velocity is experimented with to verify validity of Kalman filtering techniques for reduction of measurement noise variance.

  13. Limitations caused by distortion in room impulse response measurements by swept sine technique

    DEFF Research Database (Denmark)

    Stojic, Branko; Ciric, Dejan; Markovic, Milos

    2011-01-01

    of a measured response can be limited in a similar way as in maximum length sequence technique, although the saturation level (maximum dynamic range) is higher for swept sine technique. Thus, swept sine technique is also vulnerable to a certain extent to distortion that limits the quality of measured impulse......The significance of a room impulse response implies the requirement that its measurement should have a high level of accuracy in certain applications. One of the common problems in a measurement process is nonlinearity leading to the distortion of a room impulse response. Limitations caused...... by the distortion in room impulse response measurements by swept sine technique are analyzed here by the simulations and measurements. For the investigation, both linear and exponential swept sines are used as an excitation signal. In the simulations, this signal is modified by the nonlinearity model in the time...

  14. Measurement of precision oscillator phase noise using the two-oscillator coherent down-conversion technique

    Science.gov (United States)

    Pagnanelli, Christopher J.; Cashin, William F.

    1992-01-01

    The characterization of precision frequency standard phase noise and spurious outputs is addressed, using the two-oscillator coherent downconversion technique. Focus is on techniques for making accurate measurements of phase noise and spurious outputs within 100 KHz of a carrier. Significant sources of measurement error related to hardware design problems and inadequate measurement procedures are discussed: measurement errors resulting from system noise sources, phase-locked loop effects, and system bandwidth limitations. In addition, methods and design considerations for minimizing the effects of such errors are presented. Analytic discussions and results are supplemented with actual test data and measurements made using measurement hardware developed at the Ball Corporation, Efratom Division.

  15. ACCENT-BIAFLUX workshop 2005, trace gas and aerosol flux measurement and techniques. Abstract book

    Energy Technology Data Exchange (ETDEWEB)

    Werner, A.; Soerensen, L.L. (eds.)

    2005-04-01

    The woorkshop trace gas and aerosol flux measurement techniques in the second meeting within the Biosphere Atmosphere Exchange of Pollutions (BIAFLUX) group in the EU-network project Atmospheric Composition Change (ACCENT). The goal of the workshop is to obtain an overview of techniques for measurements of gas and aerosol fluxes and to gather the knowledge of uncertainties in flux measurements and calculations. The workshop is funded by ACCENT. The abstract book presents abstracts of 21 oral presentations and 26 poster presentations. (LN)

  16. Assessment of the sulfur hexafluoride (SF6) tracer technique for measuring enteric methane emissions from cattle.

    Science.gov (United States)

    McGinn, S M; Beauchemin, K A; Iwaasa, A D; McAllister, T A

    2006-01-01

    A commonly used method of measuring enteric methane (CH4) emissions from ruminants is the SF6 tracer technique that measures respired and eructated CH4. However, within the animal, a small proportion of CH4 is produced post-ruminally and some of this may escape through the rectum. The comparison of emissions using a chamber technique that measures all enteric CH4 losses, and the SF6 tracer technique, could give some insight into the magnitude of post-ruminal emission. The objective of our study was to assess the precision and accuracy of the SF6 tracer technique against a chamber technique for cattle fed a range of diets. Using a repeated-measures design, eight beef heifers were offered a high grain or high forage diet for ad libitum or restricted (65% of ad libitum) feed intake to vary the site of digestion within the gastrointestinal tract (n = 24). The SF6 tracer technique underestimated CH4 emissions on average by 4% relative to the chamber technique. This difference was not significant (P > 0.05) and suggests low post-ruminal CH4 emissions. There was a trend for greater accuracy and precision of the SF6 tracer technique when used with cattle fed a high forage diet at a restricted level of intake. The high forage diet corresponds to the conditions of cattle grazing pasture, suggesting the SF6 tracer technique is most reliable for the grazing system.

  17. A comparison of concentration measurement techniques for the estimation of the apparent mass diffusion coefficient

    Directory of Open Access Journals (Sweden)

    L.M. Pereira

    2001-09-01

    Full Text Available In this article we compare two different techniques to measure the concentration of saline solutions for the identification of the apparent mass diffusion coefficient in soils saturated with distilled water. They are the radiation measurement technique and the electrical conductivity measurement technique. These techniques are compared in terms of measured quantities, sensitivity coefficients with respect to unknown parameters and the determinant of the information matrix. The apparent mass diffusion coefficient is estimated by utilizing simulated measurements containing random errors. The Levenberg-Marquardt method of minimization of the least-squares norm is used as the parameter estimation procedure. The effects of the volume of saline solution injected into the column devised for the experiments on the accuracy of the estimated parameters are also addressed in this article.

  18. Introduction of measurement techniques in ultrasonic electronics: Basic principles and recent trends

    Science.gov (United States)

    Mizutani, Koichi; Wakatsuki, Naoto; Ebihara, Tadashi

    2016-07-01

    Measurement — the act of measuring physical properties that we perform — has the potential to contribute to the successful advancement of sciences and society. To open doors in physics and other sciences, various measurement methods and related applications have been developed, and ultrasound has remained a useful probe, power source, and interesting measurement object for the past two centuries. In this paper, we first summarize the basic principles of ultrasound from the viewpoint of measurement techniques for readers who just have started studying or are interested in the field of ultrasonic electronics. Moreover, we also introduce recent studies — ultrasonic properties of materials, measurement techniques, piezoelectric devices, nonlinear acoustics, biomedical ultrasound, and ocean acoustics — and their trends related to measurement techniques in ultrasonic electronics to provide some ideas for related applications.

  19. Measurement of the amplitude and phase transfer functions of an optical modulator using a heterodyne technique

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Birkedal, Dan; Mørk, Jesper

    2001-01-01

    We present a new technique that measures the full amplitude and phase transfer curves of the modulator as a function of the applied bias, from which the small signal α-parameter can be calculated. The technique measures the amplitude and phase transfer functions simultaneously and directly......, compared to techniques where a time-consuming data analysis is necessary to calculate the a-parameter and an additional measurement is necessary to estimate the phase. Additionally, the chirp profile for all operation points can be calculated....

  20. Application of Ultrasonic Technique for Measurement of Instantaneous Burn Rate of Solid Propellants .

    Directory of Open Access Journals (Sweden)

    Desh Deepak

    1998-04-01

    Full Text Available The ultrasonic pulse-echo technique has been applied for the measurement of instantaneous burnrate of aluminised composite solid propellants. The tests have been carried out on end-burning 30 mmthick propellant specimens at nearly constant pressure of about 1.9 MPa. Necessary software forpost-test data processing and instantaneous burn rate computations have been developed. The burnrates measured by the ultrasonic technique have been compared with those obtained from ballisticevaluation motor tests on propellant from the same mix. An accuracy of about +- 1 per cent ininstantaneous burn rate measurements and reproducibility of results have been demonstrated byapplying ultrasonic technique.

  1. Study on measurement technique for sodium aerosols based on laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ohtaka, Masahiko; Hayashida, Hitoshi [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    2003-03-01

    Detection of small-scale sodium leak in its early stage is effective for enhancing fast reactor safety. Feasibility of the measuring technique for sodium aerosols based on LIBS was assessed. The technique is expected to enhance performance on high discrimination for the sodium aerosols with an equivalent detection limit of conventional small sodium leak detectors. Experiments using sodium aerosols were performed in order to design a measuring system and to study on some basic measuring performances. The results show the LIBS technique is feasible as a small sodium leak detector. (author)

  2. Measuring the corrosion rate of steel in concrete – effect of measurement technique, polarisation time and current

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica

    2012-01-01

    Both on-site investigations and laboratory studies have shown that different corrosion rates are obtained when different commercially available corrosion rate instruments are used. The different electrochemical techniques and the measurement parameters used, i.e. polarisation current and time......, are in some studies considered the main reasons for the variations. This paper presents an experimental study on the quantitative effect of polarisation time and current on the measured polarisation resistance – and thus the corrosion current density – of passively and actively corroding steel. Two...... electrochemical techniques often used in instruments for on-site corrosion rate measurements are investigated. On passively corroding reinforcement the measured polarisation resistance was for both techniques found to be highly affected by the polarisation time and current and no plateaus at either short or long...

  3. Techniques for Down-Sampling a Measured Surface Height Map for Model Validation

    Science.gov (United States)

    Sidick, Erkin

    2012-01-01

    This software allows one to down-sample a measured surface map for model validation, not only without introducing any re-sampling errors, but also eliminating the existing measurement noise and measurement errors. The software tool of the current two new techniques can be used in all optical model validation processes involving large space optical surfaces

  4. A non-Gaussian distribution quantifies distances measured with fluorescence localization techniques

    DEFF Research Database (Denmark)

    Churchman, L.S.; Flyvbjerg, H.; Spudich, J.A.

    2006-01-01

    When single-molecule fluorescence localization techniques are pushed to their lower limits in attempts to measure ever-shorter distances, measurement errors become important to understand. Here we describe the non-Gaussian distribution of measured distances that is the key to proper interpretation...

  5. Measurement of Device Parameters Using Image Recovery Techniques in Large-Scale IC Devices

    Science.gov (United States)

    Scheick, Leif; Edmonds, Larry

    2004-01-01

    Devices that respond to radiation on a cell level will produce histograms showing the relative frequency of cell damage as a function of damage. The measured distribution is the convolution of distributions from radiation responses, measurement noise, and manufacturing parameters. A method of extracting device characteristics and parameters from measured distributions via mathematical and image subtraction techniques is described.

  6. Overview of Photogrammetric Measurement Techniques in Minimally Invasive Surgery Using Endoscopes

    Science.gov (United States)

    Conen, N.; Luhmann, T.

    2017-05-01

    This contribution provides an overview of various photogrammetric measurement techniques in minimally invasive surgery and presents a self-developed prototypical trinocular endoscope for reliable surface measurements. Most of the presented techniques focus on applications regarding laparoscopy, which mean endoscopic operations in the abdominal or pelvic cavities. Since endoscopic operations are very demanding to the surgeon, various assistant systems have been developed. Imaging systems may use photogrammetric techniques in order to perform 3D measurements during operation. The intra-operatively acquired 3D data may be used for analysis, model registration, guidance or documentation. Passive and active techniques have been miniaturised, integrated into endoscopes and investigated by several research groups. The main advantages and disadvantages of several active and passive techniques adapted to laparoscopy are described in this contribution. Additionally, a self-developed trinocular endoscope is described and evaluated.

  7. Assessment of strain measurement techniques to characterise mechanical properties of structural steel

    Directory of Open Access Journals (Sweden)

    H.B. Motra

    2014-12-01

    Full Text Available Strain measurement is important in mechanical testing. A wide variety of techniques exists for measuring strain in the tensile test; namely the strain gauge, extensometer, stress and strain determined by machine crosshead motion, Geometric Moire technique, optical strain measurement techniques and others. Each technique has its own advantages and disadvantages. The purpose of this study is to quantitatively compare the strain measurement techniques. To carry out the tensile test experiments for S 235, sixty samples were cut from the web of the I-profile in longitudinal and transverse directions in four different dimensions. The geometry of samples are analysed by 3D scanner and vernier caliper. In addition, the strain values were determined by using strain gauge, extensometer and machine crosshead motion. Three techniques of strain measurement are compared in quantitative manner based on the calculation of mechanical properties (modulus of elasticity, yield strength, tensile strength, percentage elongation at maximum force of structural steel. A statistical information was used for evaluating the results. It is seen that the extensometer and strain gauge provided reliable data, however the extensometer offers several advantages over the strain gauge and crosshead motion for testing structural steel in tension. Furthermore, estimation of measurement uncertainty is presented for the basic material parameters extracted through strain measurement.

  8. A High-Resolution Antenna Diagnostics Technique for Spherical Nesr-Field Measurements

    DEFF Research Database (Denmark)

    Cappellin, Cecilia; Breinbjerg, Olav; Frandsen, Aksel

    2005-01-01

    A new diagnostics technique for spherical near-field antenna measurements, that can provide a high spatial resolution of the reconstructed aperture field, is presented. This technique is realized by transforming the spherical wave expansion (SWE) of the radiated field into the corresponding plane...

  9. In vivo mitochondrial oxygen tension measured by a delayed fluorescence lifetime technique

    NARCIS (Netherlands)

    E.G. Mik (Egbert); T. Johannes (Tanja); C.J. Zuurbier (Coert Jozef); A. Heinen (Andre); J.H.P.M. Houben-Weerts (Judith); G.M. Balestra (Gianmarco); J. Stap (Jan); J.F. Beek (Johan); C. Ince (Can)

    2008-01-01

    textabstractMitochondrial oxygen tension (mitoPO2) is a key parameter for cellular function, which is considered to be affected under various pathophysiological circumstances. Although many techniques for assessing in vivo oxygenation are available, no technique for measuring mitoPO2in vivo exists.

  10. Double phi-Step theta-Scanning Technique for Spherical Near-Field Antenna Measurements

    DEFF Research Database (Denmark)

    Laitinen, Tommi

    2008-01-01

    Probe-corrected spherical near-field antenna measurements with an arbitrary probe set certain requirements on an applicable scanning technique. The computational complexity of the general high-order probe correction technique for an arbitrary probe, that is based on the Phi scanning, is O(N4), wh...

  11. Heterodyne technique for measuring the amplitude and phase transfer functions of an optical modulator

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Birkedal, Dan; Mørk, Jesper

    2002-01-01

    In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From...

  12. Technical Note: How image processing facilitates the rising bubble technique for discharge measurement

    NARCIS (Netherlands)

    Hilgersom, K.P.; Luxemburg, W.M.J.

    2012-01-01

    In this article, we rehabilitate the integrating rising bubble technique as an effective means of obtaining discharge measurements. Since Sargent (1981, 1982a), the technique has not been applied widely, mainly as a result of practical difficulties. We hypothesize that modern image processing

  13. Measurement techniques and instruments suitable for life-prediction testing of photovoltaic arrays. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Noel, G.T.; Sliemers, F.A.; Deringer, G.C.; Wood, V.E.; Wilkes, K.E.; Gaines, G.B.; Carmichael, D.C.

    1978-01-15

    The validation of a service life of 20 years for low-cost photovoltaic arrays must be accomplished through accelerated life-prediction tests. A methodology for such tests has been developed in a preceding study. The results discussed consist of the initial identification and assessment of all known measurement techniques and instruments that might be used in these life-prediction tests. Array failure modes, relevant materials property changes, and primary degradation mechanisms are discussed as a prerequisite to identifying suitable measurement techniques and instruments. Candidate techniques and instruments are identified on the basis of extensive reviews of published and unpublished information. These methods are organized in six measurement categories--chemical, electrical, optical, thermal, mechanical, and ''other physicals''. Using specified evaluation criteria, the most promising techniques and instruments for use in life-prediction tests of arrays are then selected. These recommended techniques and their characteristics are described. Recommendations are made regarding establishment of the adequacy, particularly with respect to precision, of the more fully developed techniques for this application, and regarding the experimental evaluation of promising developmental techniques. Measurement needs not satisfied by presently available techniques/instruments are also identified.

  14. A Novel Microcharacterization Technique in the Measurement of Strain and Orientation Gradient in Advanced Materials

    Science.gov (United States)

    Garmestai, H.; Harris, K.; Lourenco, L.

    1997-01-01

    Representation of morphology and evolution of the microstructure during processing and their relation to properties requires proper experimental techniques. Residual strains, lattice distortion, and texture (micro-texture) at the interface and the matrix of a layered structure or a functionally gradient material and their variation are among parameters important in materials characterization but hard to measure with present experimental techniques. Current techniques available to measure changes in interred material parameters (residual stress, micro-texture, microplasticity) produce results which are either qualitative or unreliable. This problem becomes even more complicated in the case of a temperature variation. These parameters affect many of the mechanical properties of advanced materials including stress-strain relation, ductility, creep, and fatigue. A review of some novel experimental techniques using recent advances in electron microscopy is presented here to measure internal stress, (micro)texture, interracial strength and (sub)grain formation and realignment. Two of these techniques are combined in the chamber of an Environmental Scanning Electron Microscope to measure strain and orientation gradients in advanced materials. These techniques which include Backscattered Kikuchi Diffractometry (BKD) and Microscopic Strain Field Analysis are used to characterize metallic and intermetallic matrix composites and superplastic materials. These techniques are compared with the more conventional x-ray diffraction and indentation techniques.

  15. Measurement of the absorption coefficient of a glucose solution through transmission of light and polarymetry techniques

    Science.gov (United States)

    Yáñez M., J.

    2011-10-01

    Diabetes is a disease with no cure, but can be controlled to improve the quality of life of sufferers. Currently there are means to control, but this means they have the disadvantage that in order to measure the amount of glucose is necessary to take blood samples that are painful. This paper presents a system for measuring glucose using non-invasive optical techniques: using absorption spectroscopy and polarimetry technique. It shows the results obtained from experiments done on samples containing distilled water and different amounts of glucose to study the absorption coefficient of glucose with both techniques. Water is used because it is one of the main elements in the blood and interferes with glucose measurement. This experiment will develop a prototype to measure glucose through a non-invasive technique.

  16. A novel technique for the measurement of the avalanche fluctuation of gaseous detectors

    CERN Document Server

    Kobayashi, Makoto; Kawaguchi, Tomohiko; Fujii, Keisuke; Fusayasu, Takahiro; Ikematsu, Katsumasa; Kato, Yukihiro; Kawada, Shin-ichi; Matsuda, Takeshi; Settles, Ronald Dean; Sugiyama, Akira; Takahashi, Tohru; Tian, Junping; Watanabe, Takashi; Yonamine, Ryo

    2016-01-01

    We have developed a novel technique for the measurement of the avalanche fluctuation of gaseous detectors using a UV laser. The technique is simple and requires a short data-taking time of about ten minutes. Furthermore, it is applicable for relatively low gas gains. Our experimental setup as well as the measurement principle, and the results obtained with a stack of Gas Electron Multipliers (GEMs) operated in several gas mixtures are presented.

  17. A novel technique for the measurement of the avalanche fluctuation of gaseous detectors

    Science.gov (United States)

    Kobayashi, M.; Ogawa, T.; Kawaguchi, T.; Fujii, K.; Fusayasu, T.; Ikematsu, K.; Kato, Y.; Kawada, S.; Matsuda, T.; Settles, R. D.; Sugiyama, A.; Takahashi, T.; Tian, J.; Watanabe, T.; Yonamine, R.

    2017-02-01

    We have developed a novel technique for the measurement of the avalanche fluctuation of gaseous detectors using a UV laser. The technique is simple and requires a short data-taking time of about ten minutes. Furthermore, it is applicable for relatively low gas gains. Our experimental setup as well as the measurement principle, and the results obtained with a stack of Gas Electron Multipliers (GEMs) operated in several gas mixtures are presented.

  18. Laser and acoustic Doppler techniques for the measurement of fluid velocities

    Science.gov (United States)

    Cliff, W. C.

    1975-01-01

    An overview of current laser and acoustic Doppler techniques is presented. Results obtained by Doppler anemometry and conventional sensors are compared. Comparisons include simultaneous velocity measurements by hot wire and a three-dimensional laser anemometer made in a gaseous pipe flow as well as direct comparisons of atmospheric velocities measured with propeller and cup anemometry. Scanning techniques are also discussed. Conclusions and recommendations for future work are presented.

  19. Techniques for determining propulsion system forces for accurate high speed vehicle drag measurements in flight

    Science.gov (United States)

    Arnaiz, H. H.

    1975-01-01

    As part of a NASA program to evaluate current methods of predicting the performance of large, supersonic airplanes, the drag of the XB-70 airplane was measured accurately in flight at Mach numbers from 0.75 to 2.5. This paper describes the techniques used to determine engine net thrust and the drag forces charged to the propulsion system that were required for the in-flight drag measurements. The accuracy of the measurements and the application of the measurement techniques to aircraft with different propulsion systems are discussed. Examples of results obtained for the XB-70 airplane are presented.

  20. Note: A non-invasive electronic measurement technique to measure the embedded four resistive elements in a Wheatstone bridge sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ravelo Arias, S. I.; Ramírez Muñoz, D. [Department of Electronic Engineering, University of Valencia, Avda. de la Universitat, s/n, 46100-Burjassot (Spain); Cardoso, S. [INESC Microsystems and Nanotechnologies (INESC-MN) and Institute for Nanosciences and Nanotechnologies, R. Alves Redol 9, Lisbon 1000-029 (Portugal); Ferreira, R. [INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, Braga 4715-31 (Portugal); Freitas, P. [INESC Microsystems and Nanotechnologies (INESC-MN) and Institute for Nanosciences and Nanotechnologies, R. Alves Redol 9, Lisbon 1000-029 (Portugal); INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, Braga 4715-31 (Portugal)

    2015-06-15

    The work shows a measurement technique to obtain the correct value of the four elements in a resistive Wheatstone bridge without the need to separate the physical connections existing between them. Two electronic solutions are presented, based on a source-and-measure unit and using discrete electronic components. The proposed technique brings the possibility to know the mismatching or the tolerance between the bridge resistive elements and then to pass or reject it in terms of its related common-mode rejection. Experimental results were taken in various Wheatstone resistive bridges (discrete and magnetoresistive integrated bridges) validating the proposed measurement technique specially when the bridge is micro-fabricated and there is no physical way to separate one resistive element from the others.

  1. Development of a 2D temperature measurement technique for combustion diagnostics using 2-line atomic fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Johan

    2001-01-01

    The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame regions. The viability of the technique has been tested in three extreme measurement situations: in spark ignition engine combustion, in ultra-lean combustion situations such as lean burning aero-engine concepts and, finally, in fuel-rich combustion. TLAF was successfully applied in an optical Sl engine using isooctane as fuel. The wide temperature sensitivity, 700 - 3000 K, of the technique using indium atoms allowed measurements over the entire combustion cycle in the engine to be performed. In applications in lean combustion a potential problem caused by the strong oxidation processes of indium atoms was encountered. This limits measurement times due to deposits of absorbing indium oxide on measurement windows. The seeding requirement is a disadvantage of the technique and can be a limitation in some applications. The results from experiments performed in sooting flames are very promising for thermometry measurements in such environments. Absorption by hydrocarbons and other native species was found to be negligible. Since low laser energies and low seeding concentrations could be used, the technique did not, unlike most other incoherent optical thermometry techniques, suffer interferences from LII of soot particles or LIF from PAH

  2. Measurement of void fractions by nuclear techniques; Medicion de fracciones de vacio por tecnicas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez G, A.; Vazquez G, J.; Diaz H, C.; Salinas R, G.A. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    In this work it is done a general analysis of those techniques used to determine void fractions and it is chosen a nuclear technique to be used in the heat transfer circuit of the Physics Department of the Basic Sciences Management. The used methods for the determination of void fractions are: radioactive absorption, acoustic techniques, average velocity measurement, electromagnetic flow measurement, optical methods, oscillating absorption, nuclear magnetic resonance, relation between pressure and flow oscillation, infrared absorption methods, sound neutron analysis. For the case of this work it will be treated about the radioactive absorption method which is based in the gamma rays absorption. (Author)

  3. A test technique for measuring lightning-induced voltages on aircraft electrical circuits

    Science.gov (United States)

    Walko, L. C.

    1974-01-01

    The development of a test technique used for the measurement of lightning-induced voltages in the electrical circuits of a complete aircraft is described. The resultant technique utilizes a portable device known as a transient analyzer capable of generating unidirectional current impulses similar to lightning current surges, but at a lower current level. A linear relationship between the magnitude of lightning current and the magnitude of induced voltage permitted the scaling up of measured induced values to full threat levels. The test technique was found to be practical when used on a complete aircraft.

  4. Comparing and assessing different measurement techniques for mercury in coal systhesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, D.P.; Richardson, C.F. [Radian Corporation, Austin, TX (United States)

    1995-11-01

    Three mercury measurement techniques were performed on synthesis gas streams before and after an amine-based sulfur removal system. The syngas was sampled using (1) gas impingers containing a nitric acid-hydrogen peroxide solution, (2) coconut-based charcoal sorbent, and (3) an on-line atomic absorption spectrophotometer equipped with a gold amalgamation trap and cold vapor cell. Various impinger solutions were applied upstream of the gold amalgamation trap to remove hydrogen sulfide and isolate oxidized and elemental species of mercury. The results from these three techniques are compared to provide an assessment of these measurement techniques in reducing gas atmospheres.

  5. Measurement of volatilized mercury by a mini-system: a simple, reliable and reproducible technique

    Directory of Open Access Journals (Sweden)

    Cursino Luciana

    2003-01-01

    Full Text Available A simple and easy new technique for volatilized mercury determination in biological systems was developed. This technique is fast and sensitive and can overcome the problems that arise due to the extremely low readings during the measurements and reproducibility in biological material (bacteria. It measures directly the volatilized metallic mercury of bacteria by means of a chemical adsorbent in a coupled mini-system, as a modified technique for mercury in air analysis. It is potentially of interest to the bioremediation and bacterial mercury resistance communities

  6. Stream flow rate measurement using tracer techniques at the Kemubu Agricultural Development Authority (KADA), Kelantan

    Energy Technology Data Exchange (ETDEWEB)

    Daud Mohammad; Abd Razak Hamzah; Wan Abd Aziz Wan Mohamad; Juhari Yusoff; Wan Zakaria Wan Mohd Tahir

    1985-06-01

    Measuring the flow rate of a water course is one of the basic operations in hydrology, being of general relevance to water problems and of particular importance in the planning of water control schemes. The techniques commonly used in streamflow gauging are either by a current meter of tracer dilution method. This paper describes the latter technique in which radioisotope Tc-99m was used as a tracer in streamflow measurements performed in 1983 in a few selected irrigation canals and pump house under the Kemubu Agriculture Development Authority (KADA), Kelantan. Total count technique and peak-to-peak method were adopted in this study. (author).

  7. A Review of Emerging Analytical Techniques for Objective Physical Activity Measurement in Humans.

    Science.gov (United States)

    Clark, Cain C T; Barnes, Claire M; Stratton, Gareth; McNarry, Melitta A; Mackintosh, Kelly A; Summers, Huw D

    2017-03-01

    Physical inactivity is one of the most prevalent risk factors for non-communicable diseases in the world. A fundamental barrier to enhancing physical activity levels and decreasing sedentary behavior is limited by our understanding of associated measurement and analytical techniques. The number of analytical techniques for physical activity measurement has grown significantly, and although emerging techniques may advance analyses, little consensus is presently available and further synthesis is therefore required. The objective of this review was to identify the accuracy of emerging analytical techniques used for physical activity measurement in humans. We conducted a search of electronic databases using Web of Science, PubMed, and Google Scholar. This review included studies written in English and published between January 2010 and December 2014 that assessed physical activity using emerging analytical techniques and reported technique accuracy. A total of 2064 papers were initially retrieved from three databases. After duplicates were removed and remaining articles screened, 50 full-text articles were reviewed, resulting in the inclusion of 11 articles that met the eligibility criteria. Despite the diverse nature and the range in accuracy associated with some of the analytic techniques, the rapid development of analytics has demonstrated that more sensitive information about physical activity may be attained. However, further refinement of these techniques is needed.

  8. Correlation techniques for the improvement of signal-to-noise ratio in measurements with stochastic processes

    CERN Document Server

    Reddy, V R; Reddy, T G; Reddy, P Y; Reddy, K R

    2003-01-01

    An AC modulation technique is described to convert stochastic signal variations into an amplitude variation and its retrieval through Fourier analysis. It is shown that this AC detection of signals of stochastic processes when processed through auto- and cross-correlation techniques improve the signal-to-noise ratio; the correlation techniques serve a similar purpose of frequency and phase filtering as that of phase-sensitive detection. A few model calculations applied to nuclear spectroscopy measurements such as Angular Correlations, Mossbauer spectroscopy and Pulse Height Analysis reveal considerable improvement in the sensitivity of signal detection. Experimental implementation of the technique is presented in terms of amplitude variations of harmonics representing the derivatives of normal spectra. Improved detection sensitivity to spectral variations is shown to be significant. These correlation techniques are general and can be made applicable to all the fields of particle counting where measurements ar...

  9. Hydrodynamic Nuclei Concentration Technique in Cavitation Research and Comparison to Phase-Doppler Measurements

    Science.gov (United States)

    Ebert, Eric; Kröger, Willfried; Damaschke, Nils

    2015-12-01

    Small particles, especially bubbles in the micro-meter range, influence the cavitation of the propellers. The prediction of cavitation inception and water quality measurements are important in cavitation research. The Hydrodynamic Nuclei Concentration (HDNC) technique can be used for reliable bubble concentration measurements in fluid flows. The HDNC technique bases on the analysis of scattered light from the cavitation nuclei in the water. The HDNC technique can distinguish between bubbles and solid particles. The particle type classification is important, because the number concentration of solid particles is often much higher than the nuclei concentration in cavitation tunnels and in seawater. Verification experiments show, that the HDNC technique reaches similar capabilities in number concentration estimation as Phase Doppler (PD) technique in much shorter acquisition time.

  10. Influence of beverage composition on the results of erosive potential measurement by different measurement techniques.

    NARCIS (Netherlands)

    Jager, D.H.; Vieira, A.M.; Ruben, J.L.; Huysmans, M.C.D.N.J.M.

    2008-01-01

    The influence of beverage composition on the measurement of erosive potential is unclear. The aim of this study was to evaluate whether beverage composition influences the measurement of erosive potential and to evaluate the influence of exposure in small and large volumes. Eleven beverages were inc

  11. Influence of beverage composition on the results of erosive potential measurement by different measurement techniques

    NARCIS (Netherlands)

    Jager, D. H. J.; Vieira, A. M.; Ruben, J. L.; Huysmans, M. C. D. N. J. M.

    2008-01-01

    The influence of beverage composition on the measurement of erosive potential is unclear. The aim of this study was to evaluate whether beverage composition influences the measurement of erosive potential and to evaluate the influence of exposure in small and large volumes. Eleven beverages were inc

  12. Technique for measuring the three-dimensional shapes of telescope mirrors

    Science.gov (United States)

    Wang, Zhenzhou

    2016-09-01

    Telescope mirrors determine the imaging quality and the observation ability of the telescopes. Unfortunately, manufacturing highly accurate mirrors remains a bottleneck problem in space optics. One primary cause is the lack of a technique to robustly measure the three-dimensional (3-D) shapes of mirrors for inverse engineering. After centuries of study, researchers developed different techniques for testing the quality of telescope mirrors and proposed different methods for measuring the 3-D shapes of mirrors. Among them, interferometers become popular in evaluating the surface errors of the manufactured mirrors. However, interferometers could not measure some important mirror parameters, e.g., paraxial radius, geometry dimension, and eccentric errors, directly and accurately although these parameters are essential for mirror manufacturing. For those methods that could measure these parameters, their measurement accuracies are far beyond satisfactory. We present a technique for robust measurement of the 3-D shapes of mirrors with single-shot projection. Experimental results show that this technique is significantly more robust than state-of-the-art techniques, which makes it feasible for commercial devices to measure the shapes of mirrors quantitatively and robustly.

  13. Calibration of an optical condensate measurement technique using indirect static headspace gas chromatography.

    Science.gov (United States)

    Hoke, P B; Loconto, P R; McGrath, J J

    2001-12-01

    Researchers in the Department of Mechanical Engineering seek to obtain a means to measure less than 3 mg of H2O that adheres to a metal surface as condensate. The objective is to calibrate optical reflectance measurements of an aluminum surface as a function of the condensate thickness present. Collaboration with the Hazardous Substance Research Center at Michigan State University results in the development of an indirect static headspace gas chromatographic technique capable of measuring H2O in low-milligram quantities. The technique utilizes manual headspace sampling, a megabore capillary column, and a flame ionization detector. A correlation of r2 = 0.999 is obtained for the calibration of the indirect measurement technique. The calibration of the analytical instrument demonstrates adequate precision (calcium carbide to convert the H2O to acetylene. A scaled calibration technique is used to simplify handling trace water volumes. The surface reflectance measurements are found to correlate well (r2 = 0.935) with measurements of the condensate mass. This result facilitates the development of an optical mass-transfer measurement technique. This study focuses on the analytical method and its relationship with engineering research.

  14. Comparison of stress-measuring techniques at the DNA-UTP site, Rodgers Hollow, Kentucky

    Energy Technology Data Exchange (ETDEWEB)

    Finley, R.E.

    1994-12-01

    The Defense Nuclear Agency (DNA) is developing explosives technology through its Underground Technology Program (UTP). Sandia National Laboratories (SNL) has supported the DNA by conducting research to characterize the in situ stress and rock mass deformability at one of the UTP underground sites at Rodgers Hollow, near Louisville, Kentucky on the Fort Knox Military Reservation. The purpose of SNL`s testing was to determine the in situ stress using three different measurement techniques and, if possible, to estimate the rock mass modulus near the underground opening. The three stress-measuring techniques are (1) borehole deformation measurements using overcoring, (2) Anelastic Strain Recovery (ASR) complemented by laboratory ultrasonic and mechanical properties testing, and (3) the in situ flatjack technique using cancellation pressure. Rock mass modulus around the underground opening was estimated using the load deformation history of the flatjack and surrounding rock. Borehole deformation measurements using the overcoring technique probably represent the most reliable method for in situ stress determination in boreholes up to 50 ft (15 m) deep in competent rock around an isolated excavation. The technique is used extensively by the tunneling and mining industries. The ASR technique is also a core-based technique and is used in the petroleum and natural gas industries for characterization of in situ stress from deep boreholes. The flatjack technique has also been used in the tunneling and mining industries, and until recently has been limited to measurement of the stress immediately around the excavation. Results from the flatjack technique must be further analyzed to calculate the in situ stress in the far field.

  15. An improved visualization-based force-measurement technique for short-duration hypersonic facilities

    Energy Technology Data Exchange (ETDEWEB)

    Laurence, Stuart J.; Karl, Sebastian [Institute of Aerodynamics and Flow Technology, Spacecraft Section, German Aerospace Center (DLR), Goettingen (Germany)

    2010-06-15

    This article is concerned with describing and exploring the limitations of an improved version of a recently proposed visualization-based technique for the measurement of forces and moments in short-duration hypersonic wind tunnels. The technique is based on tracking the motion of a free-flying body over a sequence of high-speed visualizations; while this idea is not new in itself, the use of high-speed digital cinematography combined with a highly accurate least-squares tracking algorithm allows improved results over what have been previously possible with such techniques. The technique precision is estimated through the analysis of artificially constructed and experimental test images, and the resulting error in acceleration measurements is characterized. For wind-tunnel scale models, position measurements to within a few microns are shown to be readily attainable. Image data from two previous experimental studies in the T5 hypervelocity shock tunnel are then reanalyzed with the improved technique: the uncertainty in the mean drag acceleration is shown to be reduced to the order of the flow unsteadiness, 2-3%, and time-resolved acceleration measurements are also shown to be possible. The response time of the technique for the configurations studied is estimated to be {proportional_to}0.5 ms. Comparisons with computations using the DLR TAU code also yield agreement to within the overall experimental uncertainty. Measurement of the pitching moment for blunt geometries still appears challenging, however. (orig.)

  16. An improved visualization-based force-measurement technique for short-duration hypersonic facilities

    Science.gov (United States)

    Laurence, Stuart J.; Karl, Sebastian

    2010-06-01

    This article is concerned with describing and exploring the limitations of an improved version of a recently proposed visualization-based technique for the measurement of forces and moments in short-duration hypersonic wind tunnels. The technique is based on tracking the motion of a free-flying body over a sequence of high-speed visualizations; while this idea is not new in itself, the use of high-speed digital cinematography combined with a highly accurate least-squares tracking algorithm allows improved results over what have been previously possible with such techniques. The technique precision is estimated through the analysis of artificially constructed and experimental test images, and the resulting error in acceleration measurements is characterized. For wind-tunnel scale models, position measurements to within a few microns are shown to be readily attainable. Image data from two previous experimental studies in the T5 hypervelocity shock tunnel are then reanalyzed with the improved technique: the uncertainty in the mean drag acceleration is shown to be reduced to the order of the flow unsteadiness, 2-3%, and time-resolved acceleration measurements are also shown to be possible. The response time of the technique for the configurations studied is estimated to be ˜0.5 ms. Comparisons with computations using the DLR TAU code also yield agreement to within the overall experimental uncertainty. Measurement of the pitching moment for blunt geometries still appears challenging, however.

  17. Vibration measurement based on the optical cross-correlation technique with femtosecond pulsed laser

    Science.gov (United States)

    Han, Jibo; Wu, Tengfei; Zhao, Chunbo; Li, Shuyi

    2016-10-01

    Two vibration measurement methods with femtosecond pulsed laser based on the optical cross-correlation technique are presented independently in this paper. The balanced optical cross-correlation technique can reflect the time jitter between the reference pluses and measurement pluses by detecting second harmonic signals using type II phase-matched nonlinear crystal and balanced amplified photo-detectors. In the first method, with the purpose of attaining the vibration displacement, the time difference of the reference pulses relative to the measurement pluses can be measured using single femtosecond pulsed laser. In the second method, there are a couple of femtosecond pulsed lasers with high pulse repetition frequency. Vibration displacement associated with cavity length can be calculated by means of precisely measuring the pulse repetition frequency. The results show that the range of measurement attains ±150μm for a 500fs pulse. These methods will be suited for vibration displacement measurement, including laboratory use, field testing and industrial application.

  18. High precision planar waveguide propagation loss measurement technique using a Fabry-Perot cavity

    DEFF Research Database (Denmark)

    Feuchter, Thomas; Thirstrup, Carsten

    1994-01-01

    A high precision measurement technique for characterizing the propagation loss in silica low-loss optical waveguides, based on measuring the contrast of a Fabry-Perot cavity, is demonstrated. The cavity consists of the waveguide coupled to two polarization-maintaining fibers, each end facet coated...

  19. Fibre-optical techniques for measuring various properties of shock waves

    NARCIS (Netherlands)

    Prinse, W.C.; Esveld, R.J. van; Oostdam, R. van; Rooijen, M. van; Bouma, R.H.B.

    1999-01-01

    For the past years we have developed several optical techniques to measure properties of shock waves. The fibre optic probe (FOP) is developed to measure the shock-wave velocity and/or the detonation velocity inside an explosive. The space resolution can be as small as 0.5 mm. Single fibres are used

  20. Construction of Weak and Strong Similarity Measures for Ordered Sets of Documents Using Fuzzy Set Techniques.

    Science.gov (United States)

    Egghe, L.; Michel, C.

    2003-01-01

    Ordered sets (OS) of documents are encountered more and more in information distribution systems, such as information retrieval systems. Classical similarity measures for ordinary sets of documents need to be extended to these ordered sets. This is done in this article using fuzzy set techniques. The practical usability of the OS-measures is…

  1. Minimizing errors in phase change correction measurements for gauge blocks using a spherical contact technique

    Science.gov (United States)

    Stoup, John R.; Faust, Bryon S.; Doiron, Theodore D.

    1998-09-01

    One of the most elusive measurement elements in gage block interferometry is the correction for the phase change on reflection. Techniques used to quantify this correction have improved over the year, but the measurement uncertainty has remained relatively constant because some error sources have proven historically difficult to reduce. The precision engineering division at the National Institute of Standards and Technology has recently developed a measurement technique that can quantify the phase change on reflection correction directly for individual gage blocks and eliminates some of the fundamental problems with historical measurement methods. Since only the top surface of the gage block is used in the measurement, wringing film inconsistencies are eliminated with this technique thereby drastically reducing the measurement uncertainty for the correction. However, block geometry and thermal issues still exist. This paper will describe the methods used to minimize the measurement uncertainty of the phase change on reflection evaluation using a spherical contact technique. The work focuses on gage block surface topography and drift eliminating algorithms for the data collection. The extrapolation of the data to an undeformed condition and the failure of these curves to follow theoretical estimates are also discussed. The wavelength dependence of the correction was directly measured for different gage block materials and manufacturers and the data will be presented.

  2. The measurement of digital systolic blood pressure by strain gauge technique

    DEFF Research Database (Denmark)

    Nielsen, P E; Bell, G; Lassen, N A

    1972-01-01

    The systolic blood pressure on the finger, toe, and ankle has been measured by a strain gauge technique in 10 normal subjects aged 17-31 years and 14 normal subjects aged 43-57 years. The standard deviation in repeated measurements lies between 2 and 6 mm Hg. The finger pressure in the younger...

  3. Measuring Three-Dimensional Thorax Motion Via Biplane Radiographic Imaging: Technique and Preliminary Results.

    Science.gov (United States)

    Baumer, Timothy G; Giles, Joshua W; Drake, Anne; Zauel, Roger; Bey, Michael J

    2016-01-01

    Measures of scapulothoracic motion are dependent on accurate imaging of the scapula and thorax. Advanced radiographic techniques can provide accurate measures of scapular motion, but the limited 3D imaging volume of these techniques often precludes measurement of thorax motion. To overcome this, a thorax coordinate system was defined based on the position of rib pairs and then compared to a conventional sternum/spine-based thorax coordinate system. Alignment of the rib-based coordinate system was dependent on the rib pairs used, with the rib3:rib4 pairing aligned to within 4.4 ± 2.1 deg of the conventional thorax coordinate system.

  4. Hybrid PIV-PTV technique for measuring blood flow in rat mesenteric vessels.

    Science.gov (United States)

    Ha, Hojin; Nam, Kweon-Ho; Lee, Sang Joon

    2012-11-01

    The micro-particle tracking velocimetry (μ-PTV) technique is used to obtain the velocity fields of blood flow in the microvasculature under in vivo conditions because it can provide the blood velocity distribution in microvessels with high spatial resolution. The in vivo μ-PTV technique usually requires a few to tens of seconds to obtain a whole velocity profile across the vessel diameter because of the limited number density of tracer particles under in vivo conditions. Thus, the μ-PTV technique alone is limited in measuring unsteady blood flows that fluctuate irregularly due to the heart beating and muscle movement in surrounding tissues. In this study, a new hybrid PIV-PTV technique was established by combining PTV and particle image velocimetry (PIV) techniques to resolve the drawbacks of the μ-PTV method in measuring blood flow in microvessels under in vivo conditions. Images of red blood cells (RBCs) and fluorescent particles in rat mesenteric vessels were obtained simultaneously. Temporal variations of the centerline blood velocity were monitored using a fast Fourier transform-based cross-correlation PIV method. The fluorescence particle images were analyzed using the μ-PTV technique to extract the spatial distribution of the velocity vectors. Data from the μ-PTV and PIV methods were combined to obtain a better estimate of the velocity profile in actual blood flow. This technique will be useful in investigating hemodynamics in microcirculation by measuring unsteady irregular blood flows more accurately.

  5. Measurements of Contaminant Dispersion in ventilated Rooms by a Passive Tracer Gas Technique

    DEFF Research Database (Denmark)

    Heiselberg, Per; Bergsøe, Niels Christian

    During recent years the interest in the passive tracer gas technique has grown rapidly. The method has mainly been used in the field for measurements of air infiltration rates in buildings. This paper describes measurements of the contaminant dispersion in a ventilated room using a passive tracer...... gas technique and the results are compared with the results from a conventional method. Vertical profiles of concentration in the middle of the room have been measured at different ventilation air flow rates and different locations of the tracer gas source. The results showed good correspondence...... between the methods within an accuracy of ± 10- 15% in large parts of the room. In regions close to the tracer gas sources the differences were larger. The results gave at the same time recommendations for the use of the passive tracer gas technique for measurements of the air infiltration rates...

  6. A cable-free impedance and gain measurement technique for electrically small antennas

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Zhang, Jiaying; Breinbjerg, Olav

    2010-01-01

    are represented in terms of spherical wave expansions (SWEs), and the propagation is accounted for by a transmission formula. In this paper the measurement results by the proposed technique will be presented for several AUTs, including a standard gain horn antenna, a monopole antenna, and an electrically small......Impedance and gain measurements for electrically small antennas represent a great challenge due to influences of the feeding cable. The leaking current along the cable and scattering effects are two main issues caused by the feed line. In this paper, a novel cable-free antenna impedance and gain...... measurement technique for electrically small antennas is proposed. The antenna properties are extracted by measuring the signal scattered by the antenna under test (AUT), when it is loaded with three known loads. The technique is based on a rigorous electromagnetic model where the probe and AUT...

  7. Towards convective heat transfer enhancement: surface modification, characterization and measurement techniques

    Science.gov (United States)

    Taha, T. J.; Thakur, D. B.; Van der Meer, T. H.

    2012-11-01

    In this work, heat transfer surface modification and heat transfer measurement technique is developed. Heat transfer investigation was aimed to study the effect of carbon nano fibers (extremely high thermal conductive material) on the enhancement level in heat transfer. Synthesis of these carbon nano structures is achieved using thermal catalytic chemical vapor deposition process (TCCVD) on a 50 μm pure nickel (Ni270) wire. The micro wire samples covered with CNF layers were subjected to a uniform flow from a nozzle. Heat transfer measurement was achieved by a controlled heat dissipation through the micro wire to attain a constant temperature during the flow. This measurement technique is adopted from hot wire anemometry calibration method. Synthesis of carbon nano structures, heat transfer surface characterization and measurement technique are evaluated. Preliminary results indicate that an average enhancement in Nusselt Number of 17% is achieved.

  8. Molecular Rayleigh Scattering Techniques Developed for Measuring Gas Flow Velocity, Density, Temperature, and Turbulence

    Science.gov (United States)

    Mielke, Amy F.; Seasholtz, Richard G.; Elam, Kristie A.; Panda, Jayanta

    2005-01-01

    Nonintrusive optical point-wise measurement techniques utilizing the principles of molecular Rayleigh scattering have been developed at the NASA Glenn Research Center to obtain time-averaged information about gas velocity, density, temperature, and turbulence, or dynamic information about gas velocity and density in unseeded flows. These techniques enable measurements that are necessary for validating computational fluid dynamics (CFD) and computational aeroacoustic (CAA) codes. Dynamic measurements allow the calculation of power spectra for the various flow properties. This type of information is currently being used in jet noise studies, correlating sound pressure fluctuations with velocity and density fluctuations to determine noise sources in jets. These nonintrusive techniques are particularly useful in supersonic flows, where seeding the flow with particles is not an option, and where the environment is too harsh for hot-wire measurements.

  9. Evaluation of Two Computational Techniques of Calculating Multipath Using Global Positioning System Carrier Phase Measurements

    Science.gov (United States)

    Gomez, Susan F.; Hood, Laura; Panneton, Robert J.; Saunders, Penny E.; Adkins, Antha; Hwu, Shian U.; Lu, Ba P.

    1996-01-01

    Two computational techniques are used to calculate differential phase errors on Global Positioning System (GPS) carrier war phase measurements due to certain multipath-producing objects. The two computational techniques are a rigorous computati electromagnetics technique called Geometric Theory of Diffraction (GTD) and the other is a simple ray tracing method. The GTD technique has been used successfully to predict microwave propagation characteristics by taking into account the dominant multipath components due to reflections and diffractions from scattering structures. The ray tracing technique only solves for reflected signals. The results from the two techniques are compared to GPS differential carrier phase ns taken on the ground using a GPS receiver in the presence of typical International Space Station (ISS) interference structures. The calculations produced using the GTD code compared to the measured results better than the ray tracing technique. The agreement was good, demonstrating that the phase errors due to multipath can be modeled and characterized using the GTD technique and characterized to a lesser fidelity using the DECAT technique. However, some discrepancies were observed. Most of the discrepancies occurred at lower devations and were either due to phase center deviations of the antenna, the background multipath environment, or the receiver itself. Selected measured and predicted differential carrier phase error results are presented and compared. Results indicate that reflections and diffractions caused by the multipath producers, located near the GPS antennas, can produce phase shifts of greater than 10 mm, and as high as 95 mm. It should be noted tl the field test configuration was meant to simulate typical ISS structures, but the two environments are not identical. The GZ and DECAT techniques have been used to calculate phase errors due to multipath o the ISS configuration to quantify the expected attitude determination errors.

  10. Variability of vascular CT measurement techniques used in the assessment abdominal aortic aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    England, Andrew, E-mail: a.england@liv.ac.u [Directorate of Medical Imaging and Radiotherapy, University of Liverpool, Johnston Building, Quadrangle, Brownlow Hill, Liverpool, L69 3GB (United Kingdom); Niker, Amanda; Redmond, Claire [Directorate of Medical Imaging and Radiotherapy, University of Liverpool, Johnston Building, Quadrangle, Brownlow Hill, Liverpool, L69 3GB (United Kingdom)

    2010-08-15

    Purpose: The aim of this project is to assess the variability of six CT measurement techniques for sizing abdominal aortic aneurysms (AAAs). Method: 37 CT scans with known AAAs were loaded on to a departmental picture archiving and communication system (PACS). A team of three observers, with experience in aortic CT measurements and the PACS performed a series of 2D and 3D measurements on the abdominal aorta. Each observer was asked to measure 3 quantities; anterior-posterior AAA diameter, maximum oblique AAA diameter, maximum aneurysm area using both 2D and 3D techniques. In order to test intra-observer variability each observer was asked to repeat their measurements. All measurements were taken using electronic callipers, under standardised viewing conditions using previously calibrated equipment. 3D measurements were conducted using a computer generated central luminal line (CLL). All measurements for this group were taken perpendicular to the CLL. Results: A total of 972 independent measurements were recorded by three observers. Mean intra-observer variability was lower for 2D diameter measurements (AP 1.3 {+-} 1.6 mm; 2D Oblique 1.2 {+-} 1.3 mm) and 2D areas (0.7 {+-} 1.3 cm{sup 2}) when compared to inter-observer variability (AP 1.7 {+-} 1.9 mm; Oblique 1.6 {+-} 1.7 mm; area 1.1 {+-} 1.5 cm{sup 2}). When comparing 2D with 3D measurements, differences were comparable except for 3D AP diameter and area which had lower inter-observer variability than their 2D counterparts (AP 2D 1.7 {+-} 1.9 mm, 3D 1.3 {+-} 1.3 mm; area 2D 1.1 {+-} 1.5 cm{sup 2}, 3D 0.7 {+-} 0.7 cm{sup 2}). 3D area measurement was the only technique which had equal variability for intra- and inter-observer measurements. Overall observer variability for the study was good with 94-100% of all paired measurements within 5.00 mm/cm{sup 2} or less. Using Pitman's test it can be confirmed that area measurements in the 3D plane have the least variability (r = 0.031) and 3D oblique measurements have

  11. A non-intrusive measurement technique applying CARS for concentration measurement in a gas mixing flow

    CERN Document Server

    Yamamoto, Ken; Moriya, Madoka; Kuriyama, Reiko; Sato, Yohei

    2015-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscope system was built and applied to a non-intrusive gas concentration measurement of a mixing flow in a millimeter-scale channel. Carbon dioxide and nitrogen were chosen as test fluids and CARS signals from the fluids were generated by adjusting the wavelengths of the Pump and the Stokes beams. The generated CARS signals, whose wavelengths are different from those of the Pump and the Stokes beams, were captured by an EM-CCD camera after filtering out the excitation beams. A calibration experiment was performed in order to confirm the applicability of the built-up CARS system by measuring the intensity of the CARS signal from known concentrations of the samples. After confirming that the measured CARS intensity was proportional to the second power of the concentrations as was theoretically predicted, the CARS intensities in the gas mixing flow channel were measured. Ten different measurement points were set and concentrations of both carbon dioxide and nitrog...

  12. Assessment of recent advances in measurement techniques for atmospheric carbon dioxide and methane observations

    Science.gov (United States)

    Zellweger, Christoph; Emmenegger, Lukas; Firdaus, Mohd; Hatakka, Juha; Heimann, Martin; Kozlova, Elena; Spain, T. Gerard; Steinbacher, Martin; van der Schoot, Marcel V.; Buchmann, Brigitte

    2016-09-01

    Until recently, atmospheric carbon dioxide (CO2) and methane (CH4) measurements were made almost exclusively using nondispersive infrared (NDIR) absorption and gas chromatography with flame ionisation detection (GC/FID) techniques, respectively. Recently, commercially available instruments based on spectroscopic techniques such as cavity ring-down spectroscopy (CRDS), off-axis integrated cavity output spectroscopy (OA-ICOS) and Fourier transform infrared (FTIR) spectroscopy have become more widely available and affordable. This resulted in a widespread use of these techniques at many measurement stations. This paper is focused on the comparison between a CRDS "travelling instrument" that has been used during performance audits within the Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO) with instruments incorporating other, more traditional techniques for measuring CO2 and CH4 (NDIR and GC/FID). We demonstrate that CRDS instruments and likely other spectroscopic techniques are suitable for WMO/GAW stations and allow a smooth continuation of historic CO2 and CH4 time series. Moreover, the analysis of the audit results indicates that the spectroscopic techniques have a number of advantages over the traditional methods which will lead to the improved accuracy of atmospheric CO2 and CH4 measurements.

  13. A Modified Ogata-Goldsand Technique for Simplified Intraoperative Measurement of Femoral Version.

    Science.gov (United States)

    Morris, William Z; Henry, Havalee; Liu, Raymond W; Streit, Jonathan J; Grant, Richard E; Cooperman, Daniel R

    2015-09-01

    Femoral anteversion can be difficult to determine intraoperatively, particularly in cases with complicated deformity. Although biplanar methodology exists for measuring femoral anteversion, the measurements are generally based on the proximal femur, without consideration for the femoral bow. We directly measured femoral version in 70 mature cadaveric femora. Using the standard Ogata-Goldsand approach, femoral version was geometrically calculated after measuring apparent neck-shaft angle and the β-angle, which is the angle between the femoral neck and proximal femoral shaft on a direct lateral view. We then used a modified β-angle, measured between the femoral neck and a line representing the entire femur. Mean anatomic femoral anteversion was 20±11 degrees. Mean calculated femoral version using the standard Ogata-Goldsand technique was 32±13 degrees, whereas mean calculated femoral version using the modified Ogata-Goldsand technique was 22±12 degrees. Repeated measures ANOVA analysis found an overall statistically significant difference between the 3 groups (POgata-Goldsand technique (POgata-Goldsand technique (P=0.76). Standard biplanar imaging techniques do not account for the femoral bow and can significantly overestimate femoral anteversion. If a line is drawn from the posterior femoral condyles to the posterior aspect of the greater trochanter, femoral anteversion is better approximated. Intraoperatively, we obtain this line by positioning a marker over the skin under fluoroscopy. Clinically, if one aims for a modified β-angle of 5 degrees, a postosteotomy anteroposterior radiograph is no longer necessary, given the knowledge that with apparent neck-shaft angles ranging from 115 to 155 degrees, version will lie within a generally accepted range between 2 and 11 degrees. In complex operative cases where imaging is desired to measure intraoperative femoral version, we recommend a modified and simplified lateral view measurement technique, which improves

  14. Development of measurement technique of large negative reactivity by an inverse kinetics rod drop method

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroyuki; Takeuchi, Mitsuo; Murayama, Yoji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-11-01

    The determination of the large negative reactivity by a rod drop method is conducted by the change of the average neutron density in the core between the critical condition at constant power and the deep subcritical condition. The neutron density is measured with a neutron detector which output the pulse or electric current signal without time delay. If an electric-current-output neutron detector is used for the measurement, a logarithmic amplifier is required to measure over a wide range of neutron density of more than 3 digits and the time delay characteristic of the amplifier may badly influence the measurement results. The authors developed a measurement technique with an inverse kinetics rod drop (IKRD) method compensating the time delay characteristic of a logarithmic amplifies, and confirmed the validity and high precision of the technique by applying it to the measurement data obtained in the characteristic experiments of the JRR-3M silicide core. (author)

  15. Cost-Effective ERT Technique for Oil-in-Water Measurement for Offshore Hydrocyclone Installations

    DEFF Research Database (Denmark)

    Løhndorf, Petar Durdevic; Hansen, Leif; Mai, Christian

    2015-01-01

    The goal of this paper is to introduce and design a cost-effective Oil-in-Water (OiW) measuring instrument, which will be investigated for its value in increasing the efficiency of a deoiling hydrocyclone. The technique investigated is based on Electrical Resistivity Tomography (ERT), which basic...... principle is to measure the resistivity of substances from multiple electrodes and from these measurements create a 2-D image of the oil and gas component in the water. This technique requires the measured components to have different electrical resistances, such as seawater which has a lower electrical...... resistance than hydrocarbon oil and gas. This work involves construction of a pilot plant, for testing the feasibility of ERT for OiW measurements, and further exploring if this measured signal can be applied as a reliable feedback signal in optimization of the hydrocyclone's efficiency. Different algorithms...

  16. Combined FTIR-micrometeorological techniques for long term measurements of greenhouse gas fluxes from agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Anna Katinka [Institut fuer Umweltphysik (IUP), Universitaet Bremen (Germany); Griffith, David; Naylor, Travis [Centre for Atmospheric Chemistry, University of Wollongong, NSW (Australia); Harvey, Mike; Smith, Murray [National Institute of Water and Atmospheric Research (NIWA), Wellington (New Zealand)

    2009-07-01

    Agricultural systems can be sources or sinks of atmospheric trace gases, and the measurement of the fluxes is necessary when evaluating both the environmental impact of agricultural activities and the impact of atmospheric pollution on agricultural production and sustainability. With the exception of CO{sub 2}, micrometeorological measurements of the fluxes of greenhouse gases are still mostly possible only in campaign mode due to the complexity and logistical requirements of the existing techniques. We have developed an instrument system for long-term flux measurements through a combination of micrometeorological flux measurement techniques (Relaxed Eddy Accumulation (REA) and Flux-Gradient (FG)) with FTIR spectroscopy. The combined technique is capable of simultaneous flux measurements of N{sub 2}O, CH{sub 4} and CO{sub 2} at paddock to regional scales continuously, over longer terms. The system was tested on a 3 weeks field campaign. The flux of the atmospheric CO{sub 2} was measured by Relaxed Eddy Accumulation, Flux-Gradient, and Eddy Correlation. Simultaneously, fluxes of CH{sub 4} and N{sub 2}O were measured by REA and FG technique.

  17. Pupil Alignment Measuring Technique and Alignment Reference for Instruments or Optical Systems

    Science.gov (United States)

    Hagopian, John G.

    2010-01-01

    A technique was created to measure the pupil alignment of instruments in situ by measuring calibrated pupil alignment references (PARs) in instruments. The PAR can also be measured using an alignment telescope or an imaging system. PAR allows the verification of the science instrument (SI) pupil alignment at the integrated science instrument module (ISIM) level of assembly at ambient and cryogenic operating temperature. This will allow verification of the ISIM+SI alignment, and provide feedback to realign the SI if necessary.

  18. Comparison of commercial analytical techniques for measuring chlorine dioxide in urban desalinated drinking water.

    Science.gov (United States)

    Ammar, T A; Abid, K Y; El-Bindary, A A; El-Sonbati, A Z

    2015-12-01

    Most drinking water industries are closely examining options to maintain a certain level of disinfectant residual through the entire distribution system. Chlorine dioxide is one of the promising disinfectants that is usually used as a secondary disinfectant, whereas the selection of the proper monitoring analytical technique to ensure disinfection and regulatory compliance has been debated within the industry. This research endeavored to objectively compare the performance of commercially available analytical techniques used for chlorine dioxide measurements (namely, chronoamperometry, DPD (N,N-diethyl-p-phenylenediamine), Lissamine Green B (LGB WET) and amperometric titration), to determine the superior technique. The commonly available commercial analytical techniques were evaluated over a wide range of chlorine dioxide concentrations. In reference to pre-defined criteria, the superior analytical technique was determined. To discern the effectiveness of such superior technique, various factors, such as sample temperature, high ionic strength, and other interferences that might influence the performance were examined. Among the four techniques, chronoamperometry technique indicates a significant level of accuracy and precision. Furthermore, the various influencing factors studied did not diminish the technique's performance where it was fairly adequate in all matrices. This study is a step towards proper disinfection monitoring and it confidently assists engineers with chlorine dioxide disinfection system planning and management.

  19. A travelling photothermal technique employing pyroelectric detection to measure thermal diffusivity of films and coatings

    Science.gov (United States)

    Philip, J.; Manjusha, M. V.; Soumya, H.

    2011-10-01

    A travelling thermal wave technique employing optical excitation and pyroelectric detection of thermal waves propagating along a material film/coating on a substrate is described. The method enables direct measurement of thermal diffusivity. The technique involves measurement of the phase lag undergone by an optically excited thermal wave as it propagates along the coating. The set up has been automated for convenient and fast data acquisition and analysis. The technique has been adapted to measurement of thermal diffusivity of a commercial paint sample coated on glass and copper substrates. It is found that thermal diffusivity of the coating is independent of the thermal conductivity of the substrate. Dependence of thermal diffusivity on coating thickness shows exponential increase, with value reaching a constant at a characteristic high thickness. Measurements have been carried out on a few other samples with wide variations in thermal diffusivity, and the results compared with available reports or results obtained following other techniques. Analyses of the results show that the technique allows measurement of thermal diffusivity of coatings and films with uncertainties better than ±2.5%.

  20. Study of Influence of Experimental Technique on Measured Particle Velocity Distributions in Fluidized Bed

    Science.gov (United States)

    Gopalan, Balaji; Shaffer, Frank

    2013-11-01

    Fluid flows that are loaded with high concentration of solid particles are common in oil and chemical processing industries. However, the opaque nature of the flow fields and the complex nature of the flow have hampered the experimental and computational study of these processes. This has led to the development of a number of customized experimental techniques for high concentration particle flows for evaluation and improvement of CFD models. This includes techniques that track few individual particles, measures average particle velocity over a small sample volume and those over a large sample volume. In this work novel high speed PIV (HsPIV), with individual particle tracking, was utilized to measure velocities of individual particles in gas-particle flow fields at the walls circulating and bubbling fluidized bed. The HsPIV measurement technique has the ability to simultaneously recognize and track thousands of individual particles in flows of high particle concentration. To determine the effect of the size of the sample volume on particle velocity measurements, the PDF of Lagrangian particle velocity was compared with the PDF of Eulerian for different domain sizes over a range of flow conditions. The results will show that measured particle velocity distribution can vary from technique to technique and this bias has to be accounted in comparison with CFD simulations.

  1. Two—Port Noise Measurement of Active Microwave Devices Using the Modified F50 Technique

    Institute of Scientific and Technical Information of China (English)

    WANGJun; CHENHuilian; TANGGaodi

    2003-01-01

    The overview of traditional measurement techniques of microwave noise indicates that the refiecto-metric and the source-pull tuners methods are all expen-sive and time-consuming because of the use of broad-band tuners and frequent calibration. Moreover, based on the two techniques, a complicated algorithm is usually needed to extract accurately the two-port noise feature parame-ters from the over-determined measured data. Recently, a novel technique is proposed to measure the noise figure at the single source (50Ω). To improve the accuracy, a mod-ified F50 Technique is presented here. And an extraction method of four noise parameters from the single measured data of F50 is also given using the Pospieszalski model of transistor and two-port noise analysis models as the addi-tional information. The experimental results demonstrate the practicability of the presented method as expected by showing the four noise parameters extracted from the sin-gle measurement of F50 are in agreement with the results obtained from source-pull tuners technique with 13 source admittances.

  2. Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods.

    Science.gov (United States)

    Fantini, Sergio; Sassaroli, Angelo; Tgavalekos, Kristen T; Kornbluth, Joshua

    2016-07-01

    Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation.

  3. Measurement of real pulsatile blood flow using X-ray PIV technique with CO2 microbubbles.

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Seo, Seung-Jun; Lim, Jae-Hong; Lee, Sang-Joon

    2015-03-06

    Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases.

  4. An efficient similarity measure technique for medical image registration

    Indian Academy of Sciences (India)

    Vilas H Gaidhane; Yogesh V Hote; Vijander Singh

    2012-12-01

    In this paper, an efficient similarity measure technique is proposed for medical image registration. The proposed approach is based on the Gerschgorin circles theorem. In this approach, image registration is carried out by considering Gerschgorin bounds of a covariance matrix of two compared images with normalized energy. The beauty of this approach is that there is no need to calculate image features like eigenvalues and eigenvectors. This technique is superior to other well-known techniques such as normalized cross-correlation method and eigenvalue-based similarity measures since it avoids the false registration and requires less computation. The proposed approach is sensitive to small defects and robust to change in illuminations and noise. Experimental results on various synthetic medical images have shown the effectiveness of the proposed technique for detecting and locating the disease in the complicated medical images.

  5. Computer Aided Measurement Laser (CAML): technique to quantify post-mastectomy lymphoedema

    Science.gov (United States)

    Trombetta, Chiara; Abundo, Paolo; Felici, Antonella; Ljoka, Concetta; Di Cori, Sandro; Rosato, Nicola; Foti, Calogero

    2012-10-01

    Lymphoedema can be a side effect of cancer treatment. Eventhough several methods for assessing lymphoedema are used in clinical practice, an objective quantification of lymphoedema has been problematic. The aim of the study was to determine the objectivity, reliability and repeatability of the computer aided measurement laser (CAML) technique. CAML technique is based on computer aided design (CAD) methods and requires an infrared laser scanner. Measurements are scanned and the information describing size and shape of the limb allows to design the model by using the CAD software. The objectivity and repeatability was established in the beginning using a phantom. Consequently a group of subjects presenting post-breast cancer lymphoedema was evaluated using as a control the contralateral limb. Results confirmed that in clinical settings CAML technique is easy to perform, rapid and provides meaningful data for assessing lymphoedema. Future research will include a comparison of upper limb CAML technique between healthy subjects and patients with known lymphoedema.

  6. Technique and experiment of active direct gas pressure measurement in coal roadway

    Energy Technology Data Exchange (ETDEWEB)

    Xue-xi Chen; Shang-quan Ma; Li-ming Qi [North China Institute of Science and Technology, Beijing (China). School of Safety Engineering

    2009-06-15

    An active measurement method and its principle was introduced considering the low success rate, special difficulty, and long measurement time of the direct gas pressure measurement currently used in coal roadways. The technology of drilling, borehole sealing depth, borehole sealing length, sealing control of the measuring process, compensatory computation of gas loss quantity and other key techniques were discussed. Finally, based on the latest instrument the authors developed, a series of experiments of direct gas pressure measurement in the coal roadways of the Jincheng and Tongchuan mine district, were carried out. The experimental results show that active gas pressure measurement technique has advantages as follows: (1) the application scope of direct gas pressure measurement technique is wide and it does not have the restriction of coal hardness, coal seam fissure and other conditions; (2) the measured results are credible, which can be tested by the same gas pressure value acquired from a different borehole in the same place; (3) the measurement process is convenient and quick, it takes about 2 to 3 days to acquire the gas pressure value in a coal seam. 8 refs., 1 fig., 2 tabs.

  7. Closure measuring technique on the datum of an end-tooth indexing table

    Science.gov (United States)

    Ling, Siying; Lou, Zhifeng; Wang, Liding

    2012-04-01

    The end-tooth indexing table (EIT) is widely used as angular reference in precision measurement or precision manufacturing fields. In order to improve the pitch accuracy of ultra-precision master gears, we designed an automatic end-tooth indexing system on a specific gear grinder. Theoretically, the indexing accuracy of an EIT can reach ±0.2″ or even more, which can meet the machining requirements of ultra-precision gears with pitch deviation up to grade 0 (ISO1328-1:1995). However, the axial and radial misalignment of an EIT to the spindle will decrease the indexing accuracy of the gear grinder. In order to solve this difficulty, precision measurement and lapping on the datum face of an EIT will be necessary. How to measure the parallelism deviation correctly at the datum of the mating face of the EIT will be another difficulty. Using the closure measuring technique which allows error separation, in this paper the measurement platform is set up, the data acquisition and handling method are presented and an experimental measurement is carried out. The maximum parallelism deviation, which is between the target face of an EIT and its mating face, was reduced from about 4 to 0.29 µm by adopting the closure measuring technique and precision lapping. It confirms that the closure measuring technique can implement precision measurement of dimensional measurands for an axisymmetric part.

  8. Technique and experiment of active direct gas pressure measurement in coal roadway

    Institute of Scientific and Technical Information of China (English)

    CHEN Xue-xi; MA Shang-quan; QI Li-ming

    2009-01-01

    An active measurement method and its principle was introduced considering the low success rate, special difficulty, and long measurement time of the direct gas pres-sure measurement currently used in coal roadways. The technology of drilling, borehole sealing depth, borehole sealing length, sealing control of the measuring process, com-pensatory computation of gas loss quantity and other key techniques were discussed. Fi-nally, based on the latest instrument the authors developed, a series of experiments of di-rect gas pressure measurement in the coal roadways of the Jincheng and Tongchuan mine district, were carried out. The experimental results show that active gas pressure measurement technique has advantages as follows: (1) the application scope of direct gas pressure measurement technique is wide and it does not have the restriction of coal hardness, coal seam fissure and other conditions; (2) the measured results are credible, which can be tested by the same gas pressure value acquired from a different borehole in the same place; (3) the measurement process is convenient and quick, it takes about 2 to 3 days to acquire the gas pressure value in a coal seam.

  9. Application of proposed mutual reciprocal inspection measurement techniques to a weapon component

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M.W.; Frankle, C.M. [Los Alamos National Lab., NM (United States); Gosnell, T.B. [Lawrence Livermore National Lab., CA (United States)

    1997-04-01

    The shape-measurement technique proposed by Russian scientists for mutual reciprocal inspections (MRI) of plutonium from dismantled nuclear weapons has been applied to a US weapon component. Measurement procedures are described. Results of the measurements are {open_quotes}self-normalized{close_quotes} to remove any classified information and further renormalized to results of previous joint US/Russian measurements of an unclassified plutonium piece. Data are presented in tabular and graphical form, conforming to the method of presentation recommended by Russian experts during the previous measurements.

  10. Wound Measurement Techniques: Comparing the Use of Ruler Method, 2D Imaging and 3D Scanner.

    Science.gov (United States)

    Shah, Aj; Wollak, C; Shah, J B

    2013-12-01

    The statistics on the growing number of non-healing wounds is alarming. In the United States, chronic wounds affect 6.5 million patients. An estimated US $25 billion is spent annually on treatment of chronic wounds and the burden is rapidly growing due to increasing health care costs, an aging population and a sharp rise in the incidence of diabetes and obesity worldwide.(1) Accurate wound measurement techniques will help health care personnel to monitor the wounds which will indirectly help improving care.(7,9) The clinical practice of measuring wounds has not improved even today.(2,3) A common method like the ruler method to measure wounds has poor interrater and intrarater reliability.(2,3) Measuring the greatest length by the greatest width perpendicular to the greatest length, the perpendicular method, is more valid and reliable than other ruler based methods.(2) Another common method like acetate tracing is more accurate than the ruler method but still has its disadvantages. These common measurement techniques are time consuming with variable inaccuracies. In this study, volumetric measurements taken with a non-contact 3-D scanner are benchmarked against the common ruler method, acetate grid tracing, and 2-D image planimetry volumetric measurement technique. A liquid volumetric fill method is used as the control volume. Results support the hypothesis that the 3-D scanner consistently shows accurate volumetric measurements in comparison to standard volumetric measurements obtained by the waterfill technique (average difference of 11%). The 3-D scanner measurement technique was found more reliable and valid compared to other three techniques, the ruler method (average difference of 75%), acetate grid tracing (average difference of 41%), and 2D planimetric measurements (average difference of 52%). Acetate tracing showed more accurate measurements compared to the ruler method (average difference of 41% (acetate tracing) compared to 75% (ruler method)). Improving

  11. Measurement of absolute displacement by a double-modulation technique based on a Michelson interferometer.

    Science.gov (United States)

    Chang, L W; Chien, P Y; Lee, C T

    1999-05-01

    A novel method is presented for of measuring absolute displacement with a synthesized wavelength interferometer. The optical phase of the interferometer is simultaneously modulated with a frequency-modulated laser diode and optical path-length difference. The error signal originating from the intensity modulation of the source is eliminated by a signal processing circuit. In addition, a lock-in technique is used to demodulate the envelope of the interferometric signal. The displacement signal is derived by the self-mixing technique.

  12. Comparison of ocular biometry measurements by applanation and immersion A-scan techniques

    Directory of Open Access Journals (Sweden)

    Dupe S. Ademola-Popoola

    2015-09-01

    Conclusion: There was a significant difference in ocular biometry measurement with the contact and immersion ultrasound techniques. The immersion technique had better repeatability, thus it is ideal in a training hospital setting in a typical in sub-Saharan Africa who have limited resources to employ a dedicated person to do biometry; and where the different operators of A-scan machines have different levels of experience and expertise.

  13. A simple technique for measuring rainfall interception by small shrub: interception flow collection box

    Science.gov (United States)

    Belmonte Serrato, F.; Romero Diaz, A.

    1998-03-01

    In this paper a simple technique for field measurement of rain water loss arising from interception and water flows associated with species of small Mediterranean shrub is described: the interception flow collection box. This technique solves the problem of installing devices to control stemflow in species with a multiple trunk and demonstrates its efficiency through the results obtained from the data observed for three species of semi-arid Mediterranean shrub: Juniperus oxycedrus, Rosmarinus officinalis and Thymus vulgaris. Finally, the empirical equations for the prediction of throughfall, stemflow and rain water loss through interception are presented for the three selected species and the validity of the technique employed is established.

  14. A technique for fast and accurate measurement of hand volumes using Archimedes' principle.

    Science.gov (United States)

    Hughes, S; Lau, J

    2008-03-01

    A new technique for measuring hand volumes using Archimedes principle is described. The technique involves the immersion of a hand in a water container placed on an electronic balance. The volume is given by the change in weight divided by the density of water. This technique was compared with the more conventional technique of immersing an object in a container with an overflow spout and collecting and weighing the volume of overflow water. The hand volume of two subjects was measured. Hand volumes were 494 +/- 6 ml and 312 +/- 7 ml for the immersion method and 476 +/- 14 ml and 302 +/- 8 ml for the overflow method for the two subjects respectively. Using plastic test objects, the mean difference between the actual and measured volume was -0.3% and 2.0% for the immersion and overflow techniques respectively. This study shows that hand volumes can be obtained more quickly than the overflow method. The technique could find an application in clinics where frequent hand volumes are required.

  15. Techniques for the measurement of the contamination of air; Technique de mesure de la contamination de l'air

    Energy Technology Data Exchange (ETDEWEB)

    Labeyrie, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    This lecture has been given at the International Symposium of Riso 1959. Methods for measuring radioactive content of the atmosphere are described, and main results found at Saclay are given, for the following contaminants: Rn, Tn and their daughter, H-3, C-14, A-41, Kr-85, I-131, and fission products as a whole. (author) [French] Ce texte est celui d'une conference-rapport prononcee au Colloque International de Riso en 1959. On indique les techniques de mesures de la contamination radioactive de l'atmosphere et les principaux resultats obtenus jusqu'ici au CEA pour: Rn et Tn et leurs derives, H-3, C-14, A-41, Kr-85, I-131, et l'ensemble des produits de fission. (auteur)

  16. Pulse-power integrated-decay technique for the measurement of thermal conductivity

    Science.gov (United States)

    Kharalkar, Nachiket M.; Hayes, Linda J.; Valvano, Jonathan W.

    2008-07-01

    A pulse-power integrated-decay technique for the measurement of thermal conductivity of biological tissues is presented. A self-heated thermistor probe is used to deliver heat and also to measure the temperature response. Three-dimensional finite element analyses are used in this paper to design and optimize the technique. The thermal conductivity measurements from the computer simulations were in close accordance with the experimental data. An empirical calibration process, performed in glycerol and agar-gelled water, provides accurate thermal conductivity measurements. An accuracy analysis evaluated multiple experimental protocols using three solutions of known thermal properties. The results indicate that the thermal decay technique protocol had better accuracy than the constant temperature heating techniques. In vitro measurements demonstrate the variability of tissue thermal conductivity, and the need to perform direct measurements for tissues of interest. The factors that may introduce error in the experimental data are (i) poor thermal/physical contact between the thermistor probe and tissue sample, (ii) water loss from tissue during the course of experimentation and (iii) temperature stability.

  17. Development of the measurement technique for nuclear data with prompt gamma-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Shoji; Furutaka, Kazuyoshi; Harada, Hideo [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works

    2002-09-01

    To obtain the thermal neutron capture cross sections of radioactive fission product nuclides as the basic data on transmutation study, a measurement technique with prompt gamma-ray spectroscopy was developed. When daughter nuclides after neutron irradiations are stable, measuring the neutron capture cross sections is impossible. Therefore, a new technique was developed to investigate these. With this, the level schemes from the information of the prompt {gamma}-rays emitted during neutron irradiation are constructed, and the cross section is deduced with the emission probabilities of prompt {gamma}-rays. The measurement system for this technique was developed, and was effective. The system enables obtaining information on the cascade {gamma}-rays necessary for constructing the level-scheme. By measuring {sup nat}Pd, the partial level-scheme was constructed, and two new levels at 1906 keV and 2400 keV were identified. By using this technique, the neutron capture cross sections of nuclides that can't be measured by an activation method can be measured. (author)

  18. High-sensitive Optical Pulse-Shape Characterization using a Beating-Contrast-Measurement Technique

    CERN Document Server

    Roncin, Vincent; Millaud, Audrey; Cramer, Romain; Jaouën, Yves; Simon, Jean-Claude

    2014-01-01

    Ultrahigh-speed optical transmission technology, such as optical time domain multiplexing or optical signal processing is a key point for increasing the communication capacity. The system performances are strongly related to pulse properties. We present an original method dedicated to short pulse-shape characterization with high repetition rate using standard optical telecommunications equipments. Its principle is based on temporal measurement of the contrast produced by the beating of two delayed optical pulses in a high bandwidth photo detector. This technique returns firstly reliable information on the pulse-shape, such as pulse width, shape and pedestal. Simulation and experimental results evaluate the high-sensitivity and the high-resolution of the technique allowing the measurement of pulse extinction ratio up to 20 dB with typical timing resolution of about 100 fs. The compatibility of the technique with high repetition rate pulse measurement offers an efficient tool for short pulse analysis.

  19. Chopped nonlinear magneto-optic rotation: a technique for precision measurements

    CERN Document Server

    Ravishankar, Harish; Natarajan, Vasant

    2011-01-01

    We have developed a technique for precise measurement of small magnetic fields using nonlinear magneto-optic rotation (NMOR). The technique relies on the resonant laser beam being chopped. During the on time, the atoms are optically pumped into an aligned ground state ($\\Delta m=2$ coherence). During the off time, they freely precess around the magnetic field at the Larmor frequency. If the on-off modulation frequency matches (twice) the Larmor precession frequency, the rotation is resonantly enhanced in every cycle, thereby making the process like a repeated Ramsey measurement of the Larmor frequency. We study chopped-NMOR in a paraffin-coated Cs vapor cell. The out-of-phase demodulated rotation shows a Lorentzian peak of linewidth 85 $\\mu$G, corresponding to a sensitivity of 0.15 nG/$\\sqrt{{\\rm Hz}}$. We discuss the potential of this technique for the measurement of an atomic electric-dipole moment.

  20. Novel technique for distributed fibre sensing based on coherent Rayleigh scattering measurements of birefringence

    Science.gov (United States)

    Lu, Xin; Soto, Marcelo A.; Thévenaz, Luc

    2016-05-01

    A novel distributed fibre sensing technique is described and experimentally validated, based on birefringence measurements using coherent Rayleigh scattering. It natively provides distributed measurements of temperature and strain with more than an order of magnitude higher sensitivity than Brillouin sensing, and requiring access to a single fibre-end. Unlike the traditional Rayleigh-based coherent optical time-domain reflectometry, this new method provides absolute measurements of the measurand and may lead to a robust discrimination between temperature and strain in combination with another technique. Since birefringence is purposely induced in the fibre by design, large degrees of freedom are offered to optimize and scale the sensitivity to a given quantity. The technique has been validated in 2 radically different types of birefringent fibres - elliptical-core and Panda polarization-maintaining fibres - with a good repeatability.

  1. Applications of Advanced Nondestructive Measurement Techniques to Address Safety of Flight Issues on NASA Spacecraft

    Science.gov (United States)

    Prosser, Bill

    2016-01-01

    Advanced nondestructive measurement techniques are critical for ensuring the reliability and safety of NASA spacecraft. Techniques such as infrared thermography, THz imaging, X-ray computed tomography and backscatter X-ray are used to detect indications of damage in spacecraft components and structures. Additionally, sensor and measurement systems are integrated into spacecraft to provide structural health monitoring to detect damaging events that occur during flight such as debris impacts during launch and assent or from micrometeoroid and orbital debris, or excessive loading due to anomalous flight conditions. A number of examples will be provided of how these nondestructive measurement techniques have been applied to resolve safety critical inspection concerns for the Space Shuttle, International Space Station (ISS), and a variety of launch vehicles and unmanned spacecraft.

  2. Recent developments in the techniques of controlling and measuring suction in unsaturated soils

    CERN Document Server

    Delage, Pierre; Tarantino, Alessandro

    2008-01-01

    The difficulty of measuring and controlling suction in unsaturated soils is one of the reasons why the development of the mechanics of unsaturated soils has not been as advanced as that of saturated soils. However, significant developments have been carried out in the last decade in this regard. In this paper, a re-view of some developments carried out in the techniques of controlling suction by using the axis translation, the osmotic method and the vapour control technique is presented. The paper also deals with some recent de-velopments in the direct measurement of suction by using high capacity tensiometers and in the measurement of high suction by using high range psychrometers. The recent progresses made in these techniques have been significant and will certainly help further experimental investigation of the hydromechanical behaviour of un-saturated soils.

  3. Molecular-Based Optical Measurement Techniques for Transition and Turbulence in High-Speed Flow

    Science.gov (United States)

    Bathel, Brett F.; Danehy, Paul M.; Cutler, Andrew D.

    2013-01-01

    High-speed laminar-to-turbulent transition and turbulence affect the control of flight vehicles, the heat transfer rate to a flight vehicle's surface, the material selected to protect such vehicles from high heating loads, the ultimate weight of a flight vehicle due to the presence of thermal protection systems, the efficiency of fuel-air mixing processes in high-speed combustion applications, etc. Gaining a fundamental understanding of the physical mechanisms involved in the transition process will lead to the development of predictive capabilities that can identify transition location and its impact on parameters like surface heating. Currently, there is no general theory that can completely describe the transition-to-turbulence process. However, transition research has led to the identification of the predominant pathways by which this process occurs. For a truly physics-based model of transition to be developed, the individual stages in the paths leading to the onset of fully turbulent flow must be well understood. This requires that each pathway be computationally modeled and experimentally characterized and validated. This may also lead to the discovery of new physical pathways. This document is intended to describe molecular based measurement techniques that have been developed, addressing the needs of the high-speed transition-to-turbulence and high-speed turbulence research fields. In particular, we focus on techniques that have either been used to study high speed transition and turbulence or techniques that show promise for studying these flows. This review is not exhaustive. In addition to the probe-based techniques described in the previous paragraph, several other classes of measurement techniques that are, or could be, used to study high speed transition and turbulence are excluded from this manuscript. For example, surface measurement techniques such as pressure and temperature paint, phosphor thermography, skin friction measurements and

  4. A Review of Experimental Techniques for Measuring Micro- to Nano-Particle-Laden Gas Flows

    Directory of Open Access Journals (Sweden)

    Chengxu Tu

    2017-01-01

    Full Text Available Dispersed micro- to nano-particle-laden gas flows are common in many engineering and environmental applications. Characterizing both their dispersed and carrier phase using experimental methods is very important for determining their properties and behavior. This paper reviews techniques for measuring the carrier phase, as well as the dispersed particles ranging from the micro- to the nano-scale. We focus not only on the developments of specific techniques over the last 20 years, but also on relationships and comparisons among these techniques. In addition to a systematic description and classification of these methods, we discuss the parameters they measure, such as particle velocity, size, composition and concentration. A more detailed review is provided for several important measurement techniques, including particle image velocimetry, the phase-Doppler particle analyzer and light-scattering intensity measurements for microparticles, as well as the scanning mobility particle sizer, the fast mobility particle sizer and the electrical low pressure impactor for nano-particles. The founding principles, development histories, various applications of these techniques and where they are going are summarized. This article provides a resource for investigators that plan to study micro- or nano-particle-laden gas flows in various contexts.

  5. Negative Expiratory Pressure Technique: An Awake Test to Measure Upper Airway Collapsibility in Adolescents

    Science.gov (United States)

    Carrera, Helena Larramona; Marcus, Carole L.; McDonough, Joseph M.; Morera, Joan C. Oliva; Huang, Jingtao; Farre, Ramon; Montserrat, Josep M.

    2015-01-01

    Study Objectives: Upper airway (UA) collapsibility is a major pathophysiologic feature of the obstructive sleep apnea syndrome (OSAS). In adolescents, it is measured by obtaining the slope of pressure-flow relationship (SPF) while applying negative nasal pressure during sleep. An easier technique to assess UA collapsibility, consisting of application of negative expiratory pressure (NEP) during wakefulness, has demonstrated differences between control and OSAS subjects. We hypothesized that the NEP technique would correlate with SPF as a measurement of UA collapsibility in adolescents. Design: During wakefulness, NEP of −5 cm H2O in the seated and supine position was applied during the first second of expiration. The area under the expiratory flow-volume curve during NEP was compared to tidal breathing (RatioNEP). In addition, adolescents underwent SPF measurements during sleep. Two SPF techniques were performed to measure the activated and relatively hypotonic UA. Setting: Pediatric sleep laboratory. Participants: Seven adolescents with OSAS and 20 controls. Results: In the seated position, there was a correlation between RatioNEP and both hypotonic SPF (r = −0.39, P = 0.04) and activated SPF (r = −0.62, P = 0.001). In the supine position, there was a correlation between RatioNEP and activated SPF (r = −0.43, P = 0.03) and a trend for hypotonic SPF (r = −0.38, P = 0.06). Conclusions: The negative expiratory pressure (NEP) technique correlates with the hypotonic and activated slope of pressure-flow relationship measurements. The seated position showed the strongest correlation. The NEP technique can be used as an alternative method to evaluate upper airway collapsibility in adolescents. Citation: Carrera HL, Marcus CL, McDonough JM, Morera JC, Huang J, Farre R, Montserrat JM. Negative expiratory pressure technique: an awake test to measure upper airway collapsibility in adolescents. SLEEP 2015;38(11):1783–1791. PMID:26158888

  6. Advanced intensity-modulation continuous-wave lidar techniques for ASCENDS CO2 column measurements

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. W.; Obland, Michael D.; Meadows, Byron

    2015-10-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  7. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for ASCENDS O2 Column Measurements

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. Wallace; Obland, Michael D.; Meadows, Byron

    2015-01-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  8. Pressure Measurement Techniques for Abdominal Hypertension: Conclusions from an Experimental Model

    Directory of Open Access Journals (Sweden)

    Sascha Santosh Chopra

    2015-01-01

    Full Text Available Introduction. Intra-abdominal pressure (IAP measurement is an indispensable tool for the diagnosis of abdominal hypertension. Different techniques have been described in the literature and applied in the clinical setting. Methods. A porcine model was created to simulate an abdominal compartment syndrome ranging from baseline IAP to 30 mmHg. Three different measurement techniques were applied, comprising telemetric piezoresistive probes at two different sites (epigastric and pelvic for direct pressure measurement and intragastric and intravesical probes for indirect measurement. Results. The mean difference between the invasive IAP measurements using telemetric pressure probes and the IVP measurements was −0.58 mmHg. The bias between the invasive IAP measurements and the IGP measurements was 3.8 mmHg. Compared to the realistic results of the intraperitoneal and intravesical measurements, the intragastric data showed a strong tendency towards decreased values. The hydrostatic character of the IAP was eliminated at high-pressure levels. Conclusion. We conclude that intragastric pressure measurement is potentially hazardous and might lead to inaccurately low intra-abdominal pressure values. This may result in missed diagnosis of elevated abdominal pressure or even ACS. The intravesical measurements showed the most accurate values during baseline pressure and both high-pressure plateaus.

  9. Measurement techniques and measurement opportunities on the spot; Messverfahren und -moeglichkeiten Vorort

    Energy Technology Data Exchange (ETDEWEB)

    Llosa Isenrich, P. [Stuttgart Univ. (Germany). Abt. Hydraulische Maschinen und Anlagen

    1997-12-31

    Verification of guarantees mostly calls for measurements on the spot. The paper deals with the guarantees that apply to small hydroelectric power stations. Already when planning a plant it should be decided what guarantees are to be demanded and how they can be verified. Specifically, measurements to verify guaranteed performance and efficiency on the spot are dealt with. Details are not given. Rather, the report wants to give an overview of methods and aspects to be taken heed of. For in-depth information, the reader is referred to the corresponding standards and guidelines. (orig.) [Deutsch] Zur Ueberpruefung von Garantien ist meistens die Durchfuehrung von Messungen vorort notwendig. Es werden die Garantien behandelt, die bei Kleinwasserkraftanlagen in Frage kommen. Bereits bei der Planung der Anlage sollte entschieden werden, welche Garantien gefordert werden sollen und wie sie ueberprueft werden koennen. Es wird speziell auf die messtechnische Ueberpruefung der Leistungs- und Wirkungsgradgarantien vorort eingegangen. Dabei werden keine Details behandelt. Es wird eher versucht ein Ueberblick ueber die Methoden und die Aspekte, die besonders beachtet werden muessen, zu vermitteln. Fuer eine Vertiefung wird auf die entsprechenden Normen und Richtlinien verwiesen. (orig.)

  10. New linear sweep technique to measure generation lifetimes in thin-film SOI MOSFET's

    Science.gov (United States)

    Venkatesan, S.; Pierret, R. F.; Neudeck, G. W.

    1994-04-01

    A new linear sweep technique to measure generation lifetimes (tau(sub g)) in silicon-on-insulator (SOI) material is presented. A detailed analytic formulation is applied to fully-depleted and partially-depleted SOI films and used to simulate the behavior of the SOI devices under linear sweep conditions. A novel algorithm accurately determines the effective generation width in fully depleted SOI films. The measurement technique is experimentally verified by applying the algorithm to fully depleted SIMOX P-channel MOSFET's where observed lifetimes ranged from 0.3 mu s to 2.4 mu s.

  11. Laser-strophometry high-resolution technique for velocity gradient measurements in fluid flows

    CERN Document Server

    Staude, Wilfried

    2001-01-01

    This book describes techniques that allow the measurement of arbitrary velocity gradient components in fluids with high spatial and temporal resolution, e.g. turbulent fluids. The techniques are based on the properties of scattered laser light. The book gives a detailed and rigorous treatment of the physical and mathematical background in a pedagogical presentation accessible to students in physics and engineering. From both the theoretical and experimental points of view, four different schemes are discussed in detail; the schemes differ in the way the velocity of the moving pattern of the scattered laser light is measured.

  12. The effect of fiber orientation on volume measurement using conductance catheter techniques.

    Science.gov (United States)

    Thaijiam, C; Gale, T J

    2006-01-01

    Estimation of parallel conductance using the impedance electrode technique is usually done assuming isotropic conditions. This may not be the best solution since the myocardium is an anisotropic material. This paper exposes the effect of fiber orientation for volume measurement using a conductor model with asymmetrical source electrodes. Simulation results show calculated volumes between surrounding materials with and without myocardial fiber orientation included in the model. We plan to extend these study results to the real heart for developing conductance catheter techniques for use in blood volume measurements in the right ventricle.

  13. Development of Time Measuring Technique to Measure the Shock Speed during the Propagation in the Free Atmosphere

    Directory of Open Access Journals (Sweden)

    M. M. Ehsan

    2012-01-01

    Full Text Available In the study of wave propagation in the free atmosphere, it is desirable to obtain time measurements to an accuracy of microsecond level. An experiment has been conducted to measure the wave speed during the propagation in the free atmosphere by the present technique. Due to sudden rupture of the diaphragm for the chamber pressure of 4.2 kg/cm2 and a wave generating in a shock tube travels with subsonic speed and the measured incident wave Mach number is 0.8 which leaves the shock tube in the free atmosphere. The measured travelling time of the incident wave to travel 61.5 cm distance in the shock tube is 2200 μsec and the same technique can apply to measure the shock wave speed. Several trigger points are installed at the exit of the shock tube in the open atmosphere to measure the strength of the wave propagation. It is observed that the wave strength decreases during the wave propagation in free atmosphere. Due to spherical expansion behind the wave, the pressure across the wave decreases. A numerical simulation is also conducted on supersonic shock wave to determine the shock speed and the travelling time in the free atmosphere. The pressures across shock wave at different locations of the shock wave are determined by solving the Euler equations and the simulation results indicate that the shock speed decreases during the propagation in the free atmosphere. In both experimental and numerical results, it is observed that the strength of the wave propagation in the free atmosphere decreases continuously due to spherical expansion.  The present technique can also be used to measure the supersonic jet velocity, the velocity of bullet and any particle velocity in subsonic or supersonic ranges.

  14. Establishment of Measurement Techniques for Sliding Bubble on a Horizontal Tube

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu-Na Kim; Park, Goon-Cherl; Cho, Hyoung-Kyu [Seoul National University, Seoul (Korea, Republic of)

    2015-10-15

    The mechanistic wall boiling model includes many parameters relevant with bubble behaviors, such as the bubble departure diameter, bubble lift-off diameter, bubble waiting time, etc. Although there have been a large number of studies investigating bubble behavior, the subjects of observation are almost bubbles on a plane or vertical tube. Since the bubble motion is highly influenced by the directions of gravitational force and the heating surfaces, it is expected that the bubble behavior on a horizontal tube is largely different from those on the other geometry. The heat exchanger of APR+ has horizontal U-tube configuration installed in a water pool, of which diameter is 50mm. The study aims to establish measurement techniques for sliding bubbles on a horizontal tube. The measurement parameters include the diameter, interface area, volume, and velocity of the bubble. Additionally, in order to analyze the force acting on the bubble, liquid velocity measurement method was proposed. This paper presents the procedure of the measurement; the phase separation technique, 3-D reconstruction technique, and velocity measurement techniques. For visualization of the sliding bubble behavior, bubble and liquid velocity measurement methods were established which use two high speed cameras and a continuous LASER for the PTV and PIV. Three steps for the bubble shape and velocity measurement (the phase separation, 3-D reconstruction, and velocity calculation), were successfully set up and verified. A PIV technique which uses two different time duration for two regions where the velocity difference is huge was proposed and tested. Using these methods, various information regarding a sliding bubble can be obtained such as bubble and liquid velocities, shape, volume, surface area etc.

  15. Clinical evaluation of analytical variations in serum creatinine measurements: why laboratories should abandon Jaffe techniques

    Directory of Open Access Journals (Sweden)

    Drion Iefke

    2012-10-01

    Full Text Available Abstract Background Non-equivalence in serum creatinine (SCr measurements across Dutch laboratories and the consequences hereof on chronic kidney disease (CKD staging were examined. Methods National data from the Dutch annual external quality organization of 2009 were used. 144 participating laboratories examined 11 pairs of commutable, value-assigned SCr specimens in the range 52–262 μmol/L, using Jaffe or enzymatic techniques. Regression equations were created for each participating laboratory (by regressing values as measured by participating laboratories on the target values of the samples sent by the external quality organization; area under the curves were examined and used to rank laboratories. The 10th and 90th percentile regression equation were selected for each technique separately. To evaluate the impact of the variability in SCr measurements and its eventual clinical consequences in a real patient population, we used a cohort of 82424 patients aged 19–106 years. The SCr measurements of these 82424 patients were introduced in the 10th and 90th percentile regression equations. The newly calculated SCr values were used to calculate an estimated glomerular filtration rate (eGFR using the 4-variable Isotope Dilution Mass Spectrometry traceable Modification of Diet in Renal Disease formula. Differences in CKD staging were examined, comparing the stratification outcomes for Jaffe and enzymatic SCr techniques. Results Jaffe techniques overestimated SCr: 21%, 12%, 10% for SCr target values 52, 73 and 94 μmol/L, respectively. For enzymatic assay these values were 0%, -1%, -2%, respectively. eGFR using the MDRD formula and SCr measured by Jaffe techniques, staged patients in a lower CKD category. Downgrading to a lower CKD stage occurred in 1-42%, 2-37% and 12–78.9% of patients for the 10th and 90th percentile laboratories respectively in CKD categories 45–60, 60–90 and >90 ml/min/1.73 m2. Using enzymatic techniques, downgrading

  16. A laser-induced heat flux technique for convective heat transfer measurements in high speed flows

    Science.gov (United States)

    Porro, A. R.; Keith, T. G., Jr.; Hingst, W. R.

    1991-01-01

    A technique is developed to measure the local convective heat transfer coefficient on a model surface in a supersonic flow field. The technique uses a laser to apply a discrete local heat flux at the model test surface, and an infrared camera system determines the local temperature distribution due to the heating. From this temperature distribution and an analysis of the heating process, a local convective heat transfer coefficient is determined. The technique was used to measure the local surface convective heat transfer coefficient distribution on a flat plate at nominal Mach numbers of 2.5, 3.0, 3.5, and 4.0. The flat plate boundary layer initially was laminar and became transitional in the measurement region. The experimentally determined convective heat transfer coefficients were generally higher than the theoretical predictions for flat plate laminar boundary layers. However, the results indicate that this nonintrusive optical measurement technique has the potential to measure surface convective heat transfer coefficients in high-speed flowfields.

  17. Comparative Calibration of Corrosion Measurements Using K-Nearest Neighbour Based Techniques

    Directory of Open Access Journals (Sweden)

    Hamed Yaman

    2016-01-01

    Full Text Available Every measuring equipment or inspection tool is known to have its own accuracy, which may affect the reliability of its measurements. This includes oil and gas pipeline corrosion defects measurements. The inspection tolerance occurred in the measurements should be treated carefully for each equipment to prevent misinterpretation of the data which could lead to incorrect assessment. This paper presents a comparison between two K-Nearest Neighbour (KNN interpolation techniques used to calibrate corrosion measurements collected by Magnetic Flux Leakage Intelligent Pig (MFL-IP with the readings of Ultrasonic Testing (UT scan device. The comparison has relied on the position of the interpolators, the weight sequence, and the error in the final enhanced metrics compared to the original measurements. Both techniques have the potential to calibrate and enhance IP measurements, with relative advantage for one technique in reducing over fitting problem. This enhancement will be used to improve the integrity assessment report that depends on the disturbed corrosion metrics of oil and gas pipelines, to decide whether the pipeline is fit for service or needs certain maintenance.

  18. High-accuracy thickness measurement of a transparent plate with the heterodyne central fringe identification technique

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wang-Tsung; Hsieh, Hung-Chih; Chang, Wei-Yao; Chen, Yen-Liang; Su, Der-Chin

    2011-07-20

    In a modified Twyman-Green interferometer, the optical path variation is measured with the heterodyne central fringe identification technique, as the light beam is focused by a displaced microscopic objective on the front/rear surface of the test transparent plate. The optical path length variation is then measured similarly after the test plate is removed. The geometrical thickness of the test plate can be calculated under the consideration of dispersion effect. This method has a wide measurable range and a high accuracy in the measurable range.

  19. MTF Measurement of EBCCD Imaging System by Using Super Resolution Technique

    Institute of Scientific and Technical Information of China (English)

    左昉; 高岳; 高稚允; 苏美开; 周立伟

    2003-01-01

    Existing methods of measurement MTF for discrete imaging system are analysed. A slit target is frequently used to measure the MTF for an imaging system. Usually there are four methods to measure the MTF for a discrete imaging system by using a slit. These methods have something imperfect respectively. But for the discrete imaging systems of under sampling it is difficult to reproduce this type of target properly since frequencies above Nyquist are folded into those below Nyquist, resulting in aliasing effect. To tackle the aliasing problem, a super resolution technique is introduced into our measurement, which gives MTF values both above and below Nyquist more accurately.

  20. Measurement of field-free molecular alignment by balanced weak field polarization technique

    Directory of Open Access Journals (Sweden)

    Peng Peng

    2015-12-01

    Full Text Available We demonstrate the measurement of field-free molecular alignment of air can be realized by combining the weak field polarization technique (WFPT with a balanced detection system. The measured signal is proportional to the alignment parameter. Periodic revival structures of the transient alignment and permanent alignment between revivals can be detected clearly by a single measurement with high sensitivity. Fourier transform spectrum of the measured signal agrees well with the calculation result and provides information of the populations of different J states in the rotational wave packet.

  1. Measurement of free heavy metal ion concentrations in soils using Donnan membrane technique

    Institute of Scientific and Technical Information of China (English)

    YI Li; HONG Yetang; WENG Liping; ZHU Yongxuan

    2005-01-01

    In natural systems heavy metals are present in very low concentrations (less than micro-molar), so precise measurement of the free metal ions is difficult. Recently, a new method has been developed called the Donnan membrane technique (DMT). Several heavy metals could be measured simultaneously using this method. Furthermore, all the metals did not interfere with each other, and the balance between the measured system and the surrounding condition could not be disturbed. Improvements were made according to the internal condition. The free heavy metal ion concentrations were measured in different systems using the improved method, and satisfied results have been obtained.

  2. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for Column CO2 Measurements

    Science.gov (United States)

    Campbell, J. F.; Lin, B.; Nehrir, A. R.; Obland, M. D.; Liu, Z.; Browell, E. V.; Chen, S.; Kooi, S. A.; Fan, T. F.

    2015-12-01

    Global and regional atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission and Atmospheric Carbon and Transport (ACT) - America airborne investigation are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity-Modulated Continuous-Wave (IM-CW) lidar techniques are being investigated as a means of facilitating CO2 measurements from space and airborne platforms to meet the mission science measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud returns. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of intervening optically thin clouds, thereby minimizing bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the Earth's surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques and provides very high (at sub-meter level) range resolution. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These techniques are used in a new data processing architecture to support the ASCENDS CarbonHawk Experiment Simulator (ACES) and ACT-America programs.

  3. Work Measurement Techniques Utilized by The Building Industry in The Midlands Province Of Zimbabwe

    Directory of Open Access Journals (Sweden)

    Tirivavi Moyo

    2014-07-01

    Full Text Available The Zimbabwean construction industry, both in the private and public sector, is characterized by cost and time overruns. Whilst the causes are innumerable, labour productivity control, through use of effective work measurement techniques, is paramount as labour constitutes a considerable portion of any construction project. It is therefore expedient that an investigation of the work measurement techniques utilized by the industry be undertaken. Focus was made on the Midlands province, it being resident to a considerable number of mining entities undergoing building construction growth momentum on the back of significant investments since 2009. The survey was undertaken through use of interview administered questionnaires on Construction Industry Federation of Zimbabwe registered companies that are resident in the province and on those that have undertaken or are undertaking construction projects within the same province. Construction companies in the Midlands province have overwhelmingly, albeit inappropriately, used the estimating technique as alluded to by 95% of the respondents. The outputs generated from use of this technique are significantly different from the actual outputs directly causing time overruns on the project sites. The other methods of time study at 33%, work sampling at 10% and synthesis at 5% have been sparingly utilized. The results from the use of time study and work sampling in combination with the estimating technique are within the allowable limits and hence these projects have no time overrun concerns emanating from the use of these techniques.

  4. Developement of new measuring techniques. A measuring system for testing GIS disconnectors in a high voltage laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Carubelli, C.; Cremonesi, F.; Santagostino, G.

    1988-10-01

    Within the framework of the cooperation between CESI (Italy) and the CPRI (Central Power Research Institute), the problem of a fast and accurate measurements systems for gas-insulated substations (GIS) disconnector testing was analyzed. The particular complexity of the transients to be studied has led to the development of a composite system in which the high frequency components are dealt with by analog techniques and medium frequency components are handled with digital techniques. Sophisticate software was developed to combine the measurement results. Further improvements are expected with the development of a fiber-optics link with an extended bandwidth and the adoption of a digital oscilloscope in order to simplify the overall management of the tests.

  5. Measuring chemical emissions from wet products--development of a new measurement technique.

    Science.gov (United States)

    Wang, Rong; Zhu, Jiping; Rastan, Soheil; Haghighat, Fariborz

    2011-09-15

    A new approach for estimating chemical emissions from wet products has been developed. The concept of such approach is that emission rates can be estimated from the amount of target chemicals in the product as a function of evaporation time. Samples were placed under a laboratory fume hood under controlled conditions (surface air velocity and temperature). Weight losses of the product were monitored and residuals at different time intervals were chemically analyzed. Emission factors of the target chemicals were then calculated based on the weight losses and residual levels of the chemicals. To demonstrate the applicability of this approach, two wet products with very different physical characteristics, one liquid and one paste-like viscous fluid, were chosen. Emissions of two principle chemicals in the products, decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) were measured. The influences of initial sample weight, surface air velocity, and temperature were investigated. The calculated emission profiles were compared with those obtained from the chamber method. The described approach could be used as an alternative screening method for emission tests of wet products, especially for compounds with low vapour pressure when sink effect poses serious challenge in traditional chamber-based emission tests.

  6. A technique using a stellar spectrographic plate to measure terrestrial ozone column depth

    Energy Technology Data Exchange (ETDEWEB)

    Wong, A.Y.

    1995-08-01

    This thesis examines the feasibility of a technique to extract ozone column depths from photographic stellar spectra in the 5000--7000 Angstrom spectral region. A stellar spectrographic plate is measured to yield the relative intensity distribution of a star`s radiation after transmission through the earth`s atmosphere. The amount of stellar radiation absorbed by the ozone Chappuis band is proportional to the ozone column depth. The measured column depth is within 10% the mean monthly value for latitude 36{degree}N, however the uncertainty is too large to make the measurement useful. This thesis shows that a 10% improvement to the photographic sensitivity uncertainty can decrease the column depth uncertainty to a level acceptable for climatic study use. This technique offers the possibility of measuring past ozone column depths.

  7. A technique using a stellar spectrographic plate to measure terrestrial ozone column depth

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Alec Y. [Univ. of California, Berkeley, CA (United States)

    1995-08-01

    This thesis examines the feasibility of a technique to extract ozone column depths from photographic stellar spectra in the 5000--7000 Angstrom spectral region. A stellar spectrographic plate is measured to yield the relative intensity distribution of a star`s radiation after transmission through the earth`s atmosphere. The amount of stellar radiation absorbed by the ozone Chappuis band is proportional to the ozone column depth. The measured column depth is within 10% the mean monthly value for latitude 36{degree}N, however the uncertainty is too large to make the measurement useful. This thesis shows that a 10% improvement to the photographic sensitivity uncertainty can decrease the column depth uncertainty to a level acceptable for climatic study use. This technique offers the possibility of measuring past ozone column depths.

  8. Novel On-wafer Radiation Pattern Measurement Technique for MEMS Actuator Based Reconfigurable Patch Antennas

    Science.gov (United States)

    Simons, Rainee N.

    2002-01-01

    The paper presents a novel on-wafer, antenna far field pattern measurement technique for microelectromechanical systems (MEMS) based reconfigurable patch antennas. The measurement technique significantly reduces the time and the cost associated with the characterization of printed antennas, fabricated on a semiconductor wafer or dielectric substrate. To measure the radiation patterns, the RF probe station is modified to accommodate an open-ended rectangular waveguide as the rotating linearly polarized sampling antenna. The open-ended waveguide is attached through a coaxial rotary joint to a Plexiglas(Trademark) arm and is driven along an arc by a stepper motor. Thus, the spinning open-ended waveguide can sample the relative field intensity of the patch as a function of the angle from bore sight. The experimental results include the measured linearly polarized and circularly polarized radiation patterns for MEMS-based frequency reconfigurable rectangular and polarization reconfigurable nearly square patch antennas, respectively.

  9. Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

    DEFF Research Database (Denmark)

    Pihlatie, M.; Rinne, J.; Ambus, P.

    2005-01-01

    Spring time nitrous oxide (N2O) emissions from an old beech (Fagus sylvatica L.) forest were measured with eddy covariance (EC) and chamber techniques. The aim was to obtain information on the spatial and temporal variability in N2O emissions and link the emissions to soil environmental parameters...... random uncertainty due to measuring fluxes close to the detection limit, we averaged the fluxes over one day periods. The variability in the chamber measurements was much smaller and dominated by high small scale spatial variability. The highest emissions measured by the EC method occurred during...... the first week of May when the trees were leafing and the soil moisture content was at its highest. If chamber techniques are used to estimate ecosystem level N2O emissions from forest soils, placement of the chambers should be considered carefully to cover the spatial variability in the soil N2O emissions...

  10. Evaluation of three new laser spectrometer techniques for in-situ carbon monoxide measurements

    Directory of Open Access Journals (Sweden)

    C. Zellweger

    2012-07-01

    Full Text Available Long-term time series of the atmospheric composition are essential for environmental research and thus require compatible, multi-decadal monitoring activities. However, the current data quality objectives of the World Meteorological Organization (WMO for carbon monoxide (CO in the atmosphere are very challenging to meet with the measurement techniques that have been used until recently. During the past few years, new spectroscopic techniques came on the market with promising properties for trace gas analytics. The current study compares three instruments that are recently commercially available (since 2011 with the up to now best available technique (vacuum UV fluorescence and provides a link to previous comparison studies. The instruments were investigated for their performance regarding repeatability, reproducibility, drift, temperature dependence, water vapour interference and linearity. Finally, all instruments were examined during a short measurement campaign to assess their applicability for long-term field measurements. It could be shown that the new techniques provide a considerably better performance compared to previous techniques, although some issues such as temperature influence and cross sensitivities need further attention.

  11. Evaluation of new laser spectrometer techniques for in-situ carbon monoxide measurements

    Science.gov (United States)

    Zellweger, C.; Steinbacher, M.; Buchmann, B.

    2012-10-01

    Long-term time series of the atmospheric composition are essential for environmental research and thus require compatible, multi-decadal monitoring activities. The current data quality objectives of the World Meteorological Organization (WMO) for carbon monoxide (CO) in the atmosphere are very challenging to meet with the measurement techniques that have been used until recently. During the past few years, new spectroscopic techniques came to market with promising properties for trace gas analytics. The current study compares three instruments that have recently become commercially available (since 2011) with the best currently available technique (Vacuum UV Fluorescence) and provides a link to previous comparison studies. The instruments were investigated for their performance regarding repeatability, reproducibility, drift, temperature dependence, water vapour interference and linearity. Finally, all instruments were examined during a short measurement campaign to assess their applicability for long-term field measurements. It could be shown that the new techniques perform considerably better compared to previous techniques, although some issues, such as temperature influence and cross sensitivities, need further attention.

  12. Evaluation of three new laser spectrometer techniques for in-situ carbon monoxide measurements

    Science.gov (United States)

    Zellweger, C.; Steinbacher, M.; Buchmann, B.

    2012-07-01

    Long-term time series of the atmospheric composition are essential for environmental research and thus require compatible, multi-decadal monitoring activities. However, the current data quality objectives of the World Meteorological Organization (WMO) for carbon monoxide (CO) in the atmosphere are very challenging to meet with the measurement techniques that have been used until recently. During the past few years, new spectroscopic techniques came on the market with promising properties for trace gas analytics. The current study compares three instruments that are recently commercially available (since 2011) with the up to now best available technique (vacuum UV fluorescence) and provides a link to previous comparison studies. The instruments were investigated for their performance regarding repeatability, reproducibility, drift, temperature dependence, water vapour interference and linearity. Finally, all instruments were examined during a short measurement campaign to assess their applicability for long-term field measurements. It could be shown that the new techniques provide a considerably better performance compared to previous techniques, although some issues such as temperature influence and cross sensitivities need further attention.

  13. Evaluation of new laser spectrometer techniques for in-situ carbon monoxide measurements

    Directory of Open Access Journals (Sweden)

    C. Zellweger

    2012-10-01

    Full Text Available Long-term time series of the atmospheric composition are essential for environmental research and thus require compatible, multi-decadal monitoring activities. The current data quality objectives of the World Meteorological Organization (WMO for carbon monoxide (CO in the atmosphere are very challenging to meet with the measurement techniques that have been used until recently. During the past few years, new spectroscopic techniques came to market with promising properties for trace gas analytics. The current study compares three instruments that have recently become commercially available (since 2011 with the best currently available technique (Vacuum UV Fluorescence and provides a link to previous comparison studies. The instruments were investigated for their performance regarding repeatability, reproducibility, drift, temperature dependence, water vapour interference and linearity. Finally, all instruments were examined during a short measurement campaign to assess their applicability for long-term field measurements. It could be shown that the new techniques perform considerably better compared to previous techniques, although some issues, such as temperature influence and cross sensitivities, need further attention.

  14. Accuracy of MRI technique in measuring tendon cross-sectional area

    DEFF Research Database (Denmark)

    Couppé, Christian; Svensson, R. B.; Elbrønd (Bibs), Vibeke Sødring

    2014-01-01

    Magnetic resonance imaging (MRI) has commonly been applied to determine tendon cross-sectional area (CSA) and length either to measure structural changes or to normalize mechanical measurements to stress and strain. The ability to reproduce CSA measurements on MRI images has been reported......, but the accuracy in relation to actual tendon dimensions has never been investigated. The purpose of this study was to compare tendon CSA measured by MRI with that measured in vitro with the mould casting technique. The knee of a horse was MRI-scanned with 1.5 and 3 tesla, and two examiners measured the patellar...... tendon CSA. Thereafter, the patellar tendon of the horse was completely dissected and embedded in an alginate cast. The CSA of the embedded tendon was measured directly by optical imaging of the cast impression. 1.5 tesla grey tendon CSA and 3 tesla grey tendon CSA were 16.5% and 13.2% lower than...

  15. Nonintrusive optical measurements of aircraft engine exhaust emissions and comparison with standard intrusive techniques.

    Science.gov (United States)

    Schäfer, K; Heland, J; Lister, D H; Wilson, C W; Howes, R J; Falk, R S; Lindermeir, E; Birk, M; Wagner, G; Haschberger, P; Bernard, M; Legras, O; Wiesen, P; Kurtenbach, R; Brockmann, K J; Kriesche, V; Hilton, M; Bishop, G; Clarke, R; Workman, J; Caola, M; Geatches, R; Burrows, R; Black, J D; Hervé, P; Vally, J

    2000-01-20

    Nonintrusive systems for the measurement on test rigs of aeroengine exhaust emissions required for engine certification (CO, NO(x), total unburned hydrocarbon, and smoke), together with CO(2) and temperature have been developed. These results have been compared with current certified intrusive measurements on an engine test. A spectroscopic database and data-analysis software has been developed to enable Fourier-transform Infrared measurement of concentrations of molecular species. CO(2), CO, and NO data showed agreement with intrusive techniques of approximately ?30%. A narrow-band spectroscopic device was used to measure CO(2) (with deviations of less than ?10% from the intrusive measurement), whereas laser-induced incandescence was used to measure particles. Future improvements to allow for the commercial use of the nonintrusive systems have been identified and the methods are applicable to any measurement of combustion emissions.

  16. Contact angle and contact angle hysteresis measurements using the capillary bridge technique.

    Science.gov (United States)

    Restagno, Frédéric; Poulard, Christophe; Cohen, Céline; Vagharchakian, Laurianne; Léger, Liliane

    2009-09-15

    A new experimental technique is proposed to easily measure both advancing and receding contact angles of a liquid on a solid surface, with unprecedented accuracy. The technique is based on the analysis of the evolution of a capillary bridge formed between a liquid bath and a solid surface (which needs to be spherical) when the distance between the surface and the liquid bath is slowly varied. The feasibility of the technique is demonstrated using a low-energy perfluorinated surface with two different test liquids (water and hexadecane). A detailed description of both experimental procedures and computational modeling are given, allowing one to determine contact angle values. It is shown that the origin of the high accuracy of this technique relies on the fact that the contact angles are automatically averaged over the whole periphery of the contact. This method appears to be particularly adapted to the characterization of surfaces with very low contact angle hysteresis.

  17. Agreement and reliability of femoral varus measurements: a comparison of four techniques

    DEFF Research Database (Denmark)

    Miles, James Edward; Svalastoga, Eiliv Lars; Eriksen, Thomas

    with the diaphysis positioned horizontally and inclined at both 12.5° and 25° to the horizontal. Radiographs were blinded, randomised and read twice by one observer using ImageJ. Using coordinate data, varus angles were calculated using Microsoft Excel for the three previously reported techniques and a novel method......, which we believed would be more reliable. Reliability between readings was assessed using the within-subject standard deviation and repeatability coefficient, and the effect of angulation on varus measurement was assessed using a mixed model ANOVA. Two of the reported techniques varied significantly (P......technique differed significantly (nearly 2°, Preported techniques, but otherwise results were similar for all methods. Although we hypothesised...

  18. Development of a wafer warpage measurement technique using Moiré-based method.

    Science.gov (United States)

    Hsieh, Hung-Lin; Huang, Yung-Guang; Tsai, Yu-Hsuan; Huang, Yao-Hui

    2016-06-01

    This paper reports on a novel technique for measuring wafer warpage, using the design concepts of moiré shift, digital moiré, autocollimator, and the scanning profiling method. The measurement system is divided into two parts: an optical moiré system and a phase analysis system. The optical arrangement can be adjusted to control the projection of a linear grating image onto the surface of a wafer to be reflected back into a CCD camera. The grating image acquired by the CCD camera is used for measurement whereas a reference grating image is obtained using the digital moiré method. By overlapping the two images of the measurement and the reference gratings, the corresponding moiré fringes are formed. The phase of the moiré fringes will change proportionally to the degree of warpage in the wafer, which can be measured by detecting variations in the phase shift of the moiré fringes in the scanning profile across the surface of the entire wafer. Measurement resolution can be controlled by adjusting the pitch size of the grating or the focal length of the focusing lens, or by adjusting the angle between the images of the measurement and reference gratings. Experiment results demonstrate that the proposed method is able to achieve an angular resolution of 0.2 μrad. As compared to the current warpage measurement techniques, the proposed method has the ability of high measurement resolution, high stability, and high flexibility.

  19. A biomechanical review of the techniques used to estimate or measure resistive forces in swimming.

    Science.gov (United States)

    Sacilotto, Gina B D; Ball, Nick; Mason, Bruce R

    2014-02-01

    Resistive or drag forces encountered during free swimming greatly influence the swim performance of elite competitive swimmers. The benefits in understanding the factors which affect the drag encountered will enhance performance within the sport. However, the current techniques used to experimentally measure or estimate drag values are questioned for their consistency, therefore limiting investigations in these factors. This paper aims to further understand how the resistive forces in swimming are measured and calculated. All techniques outlined demonstrate both strengths and weaknesses in the overall assessment of free swimming. By reviewing all techniques in this area, the reader should be able to select which one is best depending on what researchers want to gain from the testing.

  20. Current and Ongoing Internet Crime Tendencies and Techniques. Preventive Legislation Measures in Romania

    Directory of Open Access Journals (Sweden)

    Florin Postolache

    2010-06-01

    Full Text Available Internet crime techniques that pilfer from victims millions each year continue to plague the Internet through a range of methods. Trends and techniques identified by many organizations along with itsdescription are followed by preventative measures that will support you in being informed prior to entering into dealings and transactions over the Internet. Techniques as Auction Fraud, Counterfeit Cashier's Check, Credit Card Fraud, Debt Elimination, Parcel Courier Email Scheme, Employment/Business Opportunities,Escrow Services Fraud, Identity Theft, Internet Extortion, Investment Fraud, Lotteries, Nigerian Letter or "419", Phishing/Spoofing, Ponzi/Pyramid, Reshipping, Spam, Third Party Receiver of Funds are clarified in this paper and, also the internet crime prevention and legislative measures are treated, too.

  1. X-ray radiographic technique for measuring density uniformity of silica aerogel

    CERN Document Server

    Tabata, Makoto; Adachi, Ichiro; Morita, Takeshi; Nishikawa, Keiko; 10.1016/j.nima.2012.09.001

    2012-01-01

    This paper proposes a new X-ray radiographic technique for measuring density uniformity of silica aerogels used as radiator in proximity-focusing ring-imaging Cherenkov detectors. To obtain high performance in a large-area detector, a key characteristic of radiator is the density (i.e. refractive index) uniformity of an individual aerogel monolith. At a refractive index of n = 1.05, our requirement for the refractive index uniformity in the transverse plane direction of an aerogel tile is |\\delta (n - 1)/(n - 1)| < 4% in a focusing dual layer radiator (with different refractive indices) scheme. We applied the radiographic technique to evaluate the density uniformity of our original aerogels from a trial production and that of Panasonic products (SP-50) as a reference, and to confirm they have sufficient density uniformity within \\pm 1% along the transverse plane direction. The measurement results show that the proposed technique can quantitatively estimate the density uniformity of aerogels.

  2. Cross-correlation measurement techniques for cavity-based axion and weakly interacting slim particle searches

    CERN Document Server

    Parker, Stephen R; Ivanov, Eugene N; Tobar, Michael E

    2015-01-01

    Weakly Interacting Slim Particles (WISPs), such as axions, are highly motivated dark matter candidates. The most sensitive experimental searches for these particles exploit WISP-to-photon conversion mechanisms and use resonant cavity structures to enhance the resulting power signal. For WISPs to constitute Cold Dark Matter their required masses correspond to photons in the microwave spectrum. As such, searches for these types of WISPs are primarily limited by the thermal cavity noise and the broadband first-stage amplifier noise. In this work we propose and then verify two cross-correlation measurement techniques for cavity-based WISP searches. These are two channel measurement schemes where the cross-spectrum is computed, rejecting uncorrelated noise sources while still retaining correlated signals such as those generated by WISPs. The first technique allows for the cavity thermal spectrum to be observed with an enhanced resolution. The second technique cross-correlates two individual cavity/amplifier system...

  3. Testing of a technique for remotely measuring water salinity in an estuarine environment

    Science.gov (United States)

    Thomann, G. C.

    1975-01-01

    An aircraft experiment was flown on November 7, 1973 to test a technique for remote water salinity measurement. Apparent temperatures at 21 cm and 8-14 micron wavelengths were recorded on eight runs over a line along which the salinity varied from 5 to 30%. Boat measurements were used for calibration and accuracy calculations. Overall RMS accuracy over the complete range of salinities was 3.6%. Overall RMS accuracy for salinities greater than 10%, where the technique is more sensitive, was 2.6%. Much of this error is believed to be due to inability to exactly locate boat and aircraft positions. The standard deviation over the eight runs for salinities or = 10% is 1.4%; this error contains a component due to mislocation of the aircraft also. It is believed that operational use of the technique is possible with accuracies of 1-2%.

  4. Measurement techniques for in situ stresses around underground constructions in a deep clay formation

    Directory of Open Access Journals (Sweden)

    Li X.L.

    2010-06-01

    Full Text Available Disposal in deep underground geological formations is internationally recognized as the most viable option for the long-term management of high-level radioactive waste. In Belgium, the Boom clay formation is extensively studied in this context, in particular at the 225 m deep HADES Underground Research Facility in Mol. A cost-effective design of deep underground structures requires an accurate assessment of the in situ stresses; a good estimation of these stresses is also essential when interpreting in situ experiments regarding the hydro-mechanical behaviour of the host formation. Different measurement techniques are available to provide data on the stress evolution and other mechanical properties of the geological formation. The measurement can be direct (measurement of total pressure, or it can be an indirect technique, deriving the stress from related quantities such as strain (changes in structural members. Most total stress measurements are performed through permanently installed sensors; also once-only measurements are performed through specific methods (e.g. pressuremeter. Direct measurement of the stress state is challenging due to the complex mechanical behaviour of the clay, and the fact that the sensor installation inevitably disturbs the original stress field. This paper describes ways to deal with these problems and presents the results obtained using different techniques at HADES.

  5. A critical review of wetland greenhouse gas measurement techniques and scaling considerations

    Science.gov (United States)

    Allen, S. T.; Krauss, K. W.; Stagg, C. L.; Neubauer, S. C.

    2016-12-01

    The role of wetlands in terrestrial greenhouse gas fluxes is disproportionately large compared to the relatively small terrestrial area they encompass. There is an established and growing interest in accurately measuring these fluxes, and extrapolating inferences to larger spatial scales. However, a lack of uniformity in measurement approaches impedes progress because it is a challenge to synthesize data, parameterize models, and develop generalizable concepts from disparate data. Furthermore, pairing different methods can result in double-accounting and other aggregation errors. Our objective is to review gas flux measurement techniques and synthesize concepts, factors, and constraints associated with measuring and scaling greenhouse gas fluxes. This work will contribute to a conceptual framework designed to aid in the collection and use of gas flux data obtained by different methods. This review focuses specifically on wetlands which have both distinct transport processes and a unique biogeochemical environment, causing gas fluxes that are not prominent in other terrestrial or aquatic systems. We review techniques and implications of measuring at different steps along the soil-plant-atmosphere continuum; an emphasis of this work is identifying pathways and transit times for different fluxes in different wetland hydrogeomorphic settings. Measurement location along the path from source to atmosphere connotes the spatial and temporal scales at which a technique is applied, the spatiotemporal representation, and the factors that constrain extrapolation.

  6. Efficient optical design and measurement technique to six sigma laser processing

    Science.gov (United States)

    Scaggs, Michael; Haas, Gil

    2014-03-01

    A six sigma laser processing system is proposed that utilizes real time measurement of ISO 11146 and ISO 13694 laser beam parameters without disrupting the process beam and with minimal loss. If key laser beam parameters can be measured during a laser process, without a disruption to the process, then a higher level of process control can be realized. The difficulty in achieving this concept to date is that most accepted beam measurement techniques are time averaged and require interruption of the laser beam and therefore have made it impractical for real time measurement which is necessary to consider six sigma process control. Utilizing an all passive optical technique to measure a laser's beam waist and other parameters for both focused and unfocused beams, the direct measurement of the ISO laser beam parameters are realized without disruption to the process and with minimal loss. The technique is simple enough to be applied to low and high power systems well into the multi-kilowatt range. Through careful monitoring of all laser beam parameters via software control of upper and lower limits for these parameters, tighter quality control is possible for achieving a six sigma process. In this paper we describe the optical design for both low and high power laser systems and how six sigma laser processing may be realized.

  7. Techniques for measuring small changes in the orientation of the easy axis in permalloy films

    NARCIS (Netherlands)

    Eijkel, Kees J.M.; Haan, de Poul; Ridder, de René M.

    1988-01-01

    It is well known that the orientation of the easy axis in permalloy can be affected by annealing. The need in our research for detailed information of the behavior of the easy‐axis orientation in the temperature range from room temperature to 100 °C and the absence of measurement techniques to deriv

  8. Towards convective heat transfer enhancement: surface modification, characterization and measurement techniques

    NARCIS (Netherlands)

    Taha, T.J.; Thakur, D.B.; van der Meer, Theodorus H.

    2012-01-01

    In this work, heat transfer surface modification and heat transfer measurement technique is developed. Heat transfer investigation was aimed to study the effect of carbon nano fibers (extremely high thermal conductive material) on the enhancement level in heat transfer. Synthesis of these carbon nan

  9. Velocity field measurements in an evaporating sessile droplet by means of micro-PIV technique

    Directory of Open Access Journals (Sweden)

    Yagodnitsyna Anna

    2016-01-01

    Full Text Available Velocity fields are measured in evaporating sessile droplets on two substrates with different contact angles and contact angle hysteresis using micro resolution particle image velocimetry technique. Different flow patterns are observed in different stages of droplet evaporation: a flow with vortices and a radial flow. Flow structure is found to be similar for droplets on different substrates.

  10. Study of Phase Reconstruction Techniques applied to Smith-Purcell Radiation Measurements

    CERN Document Server

    Delerue, Nicolas; Bezshyyko, Oleg; Khodnevych, Vitalii

    2015-01-01

    Measurements of coherent radiation at accelerators typically give the absolute value of the beam profile Fourier transform but not its phase. Phase reconstruction techniques such as Hilbert transform or Kramers Kronig reconstruction are used to recover such phase. We report a study of the performances of these methods and how to optimize the reconstructed profiles.

  11. Study of Phase Reconstruction Techniques applied to Smith-Purcell Radiation Measurements

    CERN Document Server

    Delerue, Nicolas; Vieille-Grosjean, Mélissa; Bezshyyko, Oleg; Khodnevych, Vitalii

    2014-01-01

    Measurements of coherent radiation at accelerators typically give the absolute value of the beam profile Fourier transform but not its phase. Phase reconstruction techniques such as Hilbert transform or Kramers Kronig reconstruction are used to recover such phase. We report a study of the performances of these methods and how to optimize the reconstructed profiles.

  12. A Spectroscopic Technique for Local Temperature Measurement in a Micro-Optofluidic System

    NARCIS (Netherlands)

    Sharma, M.K.; Frijns, A.J.H.; Mandamparambil, R.; Smeulders, D.M.J.

    2016-01-01

    We present a spectroscopy technique to measure temperature locally in a polydimethylsiloxane micro-optofluidic chip with integrated optical fibers and minimal optical components. The device was fabricated in one step with fiber coupler grooves followed by the manual integration of the optical fibers

  13. Project 8: Using Radio-Frequency Techniques to Measure Neutrino Mass

    CERN Document Server

    Oblath, N S

    2013-01-01

    The Project 8 experiment aims to measure the neutrino mass using tritium beta decays. Beta-decay electron energies will be measured with a novel technique: as the electrons travel in a uniform magnetic field their cyclotron radiation will be detected. The frequency of each electron's cyclotron radiation is inversely proportional to its total relativistic energy; therefore, by observing the cyclotron radiation we can make a precise measurement of the electron energies. The advantages of this technique include scalability, excellent energy resolution, and low backgrounds. The collaboration is using a prototype experiment to study the feasibility of the technique with a $^{83m}$Kr source. Demonstrating the ability to see the 17.8 keV and 30.2 keV conversion electrons from $^{83m}$Kr will show that it may be possible to measure tritium beta-decay electron energies ($Q \\approx 18.6$ keV) with their cyclotron radiation. Progress on the prototype, analysis and signal-extraction techniques, and an estimate of the pot...

  14. Los Angeles phonospirometry technique: creating a normogram that correlates with peak expiratory flow measurements in children.

    Science.gov (United States)

    Ochoa, Kelly; Nunez, Jeranil; Wang, Vincent J

    2015-09-01

    Measurement of peak expiratory flow (PEF) is recommended in the assessment of patients with asthma. However, the use of PEF involves multiple barriers, which have limited its use. Phonospirometry, as assessed by a novel Los Angeles phonospirometry technique, has shown good correlation to standard PEF measurements in a pilot study on symptomatic patients with asthma. We sought to develop a normogram for phonospirometry, and to validate the PEF normogram. A convenience sample of asymptomatic children ages 3-17 years old was approached for participation in the Emergency Department. Sample size calculations determined that at least 30 children per age group (n = 450) were needed. Children were asked to perform PEF measurements and phonospirometry, measured as the length of time (in s) the child was able to chant "lalala" in a single breath. 510 children were enrolled. Spearman's rho between PEF and phonospirometry was 0.722. Phonospirometry correlated with both age and height, with a Spearman rho of 0.697 and 0.696, respectively. This was slightly lower than the correlation of PEF with age and height with Spearman rhos of 0.877 and 0.902, respectively. A normogram was developed for phonospirometry based on age and height. This study determined normal value ranges for the Los Angeles phonospirometry technique for age and height, and also showed that the technique has good correlation with PEF. This technique may be used to assess a pediatric patient with an acute asthma exacerbation.

  15. Evaluation of a Videotape Technique for Measuring Clinical Psychiatric Skills of Medical Students

    Science.gov (United States)

    Tardiff, Kenneth; And Others

    1978-01-01

    A technique developed at SUNY at Stony Brook measures changes in second-year medical students' ability to recognize psychopathology following an educational program in psychobiology. It compares ratings of videotaped interviews by the students to the ratings of the interviews made by the faculty preceptors participating in the teaching program.…

  16. Validation of the actuator line and disc techniques using the New MEXICO measurements

    DEFF Research Database (Denmark)

    Sarmast, Sasan; Shen, Wen Z.; Zhu, Wei Jun

    2016-01-01

    Actuator line and disc techniques are employed to analyse the wake obtained in the New MEXICO wind turbine experiment. The New MEXICO measurement campaign done in 2014 is a follow-up to the MEXICO campaign, which was completed in 2006. Three flow configurations in axial flow condition are simulated...

  17. Towards convective heat transfer enhancement: surface modification, characterization and measurement techniques

    NARCIS (Netherlands)

    Taha, T.J.; Thakur, D.B.; Meer, van der T.H.

    2012-01-01

    In this work, heat transfer surface modification and heat transfer measurement technique is developed. Heat transfer investigation was aimed to study the effect of carbon nano fibers (extremely high thermal conductive material) on the enhancement level in heat transfer. Synthesis of these carbon nan

  18. Phishtest: Measuring the Impact of Email Headers on the Predictive Accuracy of Machine Learning Techniques

    Science.gov (United States)

    Tout, Hicham

    2013-01-01

    The majority of documented phishing attacks have been carried by email, yet few studies have measured the impact of email headers on the predictive accuracy of machine learning techniques in detecting email phishing attacks. Research has shown that the inclusion of a limited subset of email headers as features in training machine learning…

  19. Nitrous Acid: Intercomparison of techniques and Implications of measurements for photochemistry

    Science.gov (United States)

    Pinto, J. P.; Dibb, J. E.; Stutz, J.; Tsai, J.; Ren, X.; Wood, E. C.; Zhang, R.; Lee, B.; Levy, M. E.; Rappenglueck, B.; Lefer, B. L.; Oakes, M. M.; Olaguer, E.

    2013-12-01

    Because of the importance of HONO as a radical reservoir, consistent and accurate measurements of its concentration are needed. As part of the SHARP (Study of Houston Atmospheric Radical Precursors), time series of HONO were obtained by six different measurement techniques on the roof of the Moody Tower (MT) at the University of Houston. Techniques used were long path differential optical absorption spectroscopy (DOAS), stripping coil- (UVVIS) absorption photometry (SC-AP), long-path absorption photometry (LOPAP), mist chamber/ ion chromatography (MC-IC), quantum cascade-tunable infrared laser differential absorption spectroscopy (QC-TILDAS) and ion drift -chemical ionization mass spectrometry (ID-CIMS). Various combinations of techniques were in operation during the period from 15 April through 31 May 2009. This study comparing methods is unique in that it compares several techniques entirely at ambient conditions in a polluted atmosphere. All instruments recorded a similar diurnal pattern of HONO concentrations with higher median and mean values during the night and lower values during the day throughout the entire measurement period. Highest values were observed in the final two weeks of the campaign. The MC-IC, SC-AP, and QC-TILDAS, and to a lesser extent the DOAS, tracked each other most closely. Largest differences between pairs of measurements were evident during the day for concentrations IC and QC-TILDAS converged to within about 20%, with slightly larger discrepancies when DOAS was considered. Relationships between HONO and other gas phase and aerosol species will also be considered.

  20. Measurement of wheelchair rolling resistance with a handle bar push technique

    NARCIS (Netherlands)

    van der Woude, L H V; Geurts, C; Winkelman, H; Veeger, DirkJan (H. E. J.)

    2003-01-01

    The purpose of this study was to evaluate a technique of pushing a wheelchair at the level of the handle bars as a method for measuring rolling resistance of wheelchair-user systems under different field conditions. Under standardized conditions on a motor driven treadmill, rolling resistance was de

  1. Measurement of wheelchair rolling resistance with a handle bar push technique

    NARCIS (Netherlands)

    van der Woude, L H V; Geurts, C; Winkelman, H; Veeger, DirkJan (H. E. J.)

    2003-01-01

    The purpose of this study was to evaluate a technique of pushing a wheelchair at the level of the handle bars as a method for measuring rolling resistance of wheelchair-user systems under different field conditions. Under standardized conditions on a motor driven treadmill, rolling resistance was

  2. Absorption-edge transmission technique using Ce- 139 for measurement of stable iodine concentration.

    Science.gov (United States)

    Sorenson, J A

    1979-12-01

    We have investigated a technique for measuring stable iodine concentrations by absorption-edge transmission measurements using a Ce 139 radiation source. The lanthanum daughter emits characteristic x-rays whose energies just bracket the absorption edge of iodine at 33.2 keV. Relative transmission of these x-rays is sensitive to iodine concentration in the sample, but is relatively insensitive to other elements. By applying energy-selective beam filtration, it is possible to determine the relative transmission of these closely spaced x-ray energies with NaI(Tl) detectors. Optimizations of sample thickness, detector thickness, and Ce-139 source activity are discussed. Using sample volumes of about 10 ml, one can determine iodine concentration to an uncertainty (standard deviation) of +/- 5 microgram/ml with a 5-mCi source in a measurement time of 400 sec. Potential clinical applications of the in vitro technique are discussed, along with comparative aspects of the Ce-139 technique and other absorption and fluorescence techniques for measuring stable iodine.

  3. Accuracy of vertical radial plume mapping technique in measuring lagoon gas emission

    Science.gov (United States)

    Recently, the U.S. Environmental Protection Agency (USEPA) posted a ground-based optical remote sensing method on its website called OTM 10 for measuring fugitive gas emission flux from area sources such as closed landfills. The OTM 10 utilizes the vertical radial plume mapping (VRPM) technique to c...

  4. Phishtest: Measuring the Impact of Email Headers on the Predictive Accuracy of Machine Learning Techniques

    Science.gov (United States)

    Tout, Hicham

    2013-01-01

    The majority of documented phishing attacks have been carried by email, yet few studies have measured the impact of email headers on the predictive accuracy of machine learning techniques in detecting email phishing attacks. Research has shown that the inclusion of a limited subset of email headers as features in training machine learning…

  5. Monitoring fugitive methane and natural gas emissions, validation of measurement techniques.

    Science.gov (United States)

    Robinson, Rod; Innocenti, Fabrizio; Gardiner, Tom; Helmore, Jon; Finlayson, Andrew; Connor, Andy

    2017-04-01

    The detection and quantification of fugitive and diffuse methane emissions has become an increasing priority in recent years. As the requirements for routine measurement to support industry initiatives increase there is a growing requirement to assess and validate the performance of fugitive emission measurement technologies. For reported emissions traceability and comparability of measurements is important. This talk will present recent work addressing these needs. Differential Absorption Lidar (DIAL) is a laser based remote sensing technology, able to map the concentration of gases in the atmosphere and determine emission fluxes for fugitive emissions. A description of the technique and its application for determining fugitive emissions of methane from oil and gas operations and waste management sites will be given. As DIAL has gained acceptance as a powerful tool for the measurement and quantification of fugitive emissions, and given the rich data it produces, it is being increasingly used to assess and validate other measurement approaches. In addition, to support the validation of technologies, we have developed a portable controlled release facility able to simulate the emissions from area sources. This has been used to assess and validate techniques which are used to monitor emissions. The development and capabilities of the controlled release facility will be described. This talk will report on recent studies using DIAL and the controlled release facility to validate fugitive emission measurement techniques. This includes side by side comparisons of two DIAL systems, the application of both the DIAL technique and the controlled release facility in a major study carried out in 2015 by South Coast Air Quality Management District (SCAQMD) in which a number of optical techniques were assessed and the development of a prototype method validation approach for techniques used to measure methane emissions from shale gas sites. In conclusion the talk will provide an

  6. A simple focal-length measurement technique for adaptive microlenses using z-scan

    Science.gov (United States)

    Abdelaziez, Yasser; Banerjee, Partha P.

    2004-10-01

    A simple technique for focal length measurements of adaptive micro-lenses using z-scan is reported. Focal length is one of the most important parameters of any lens. The effective focal length is measured with reference to the principal points that are not easy to find especially for micro-lenses. In addition, variable focal length microlenses pose a different challenge that makes the process of determining their exact focal length a tedious and difficult process. Classical methods such as nodal slide and magnification have been used for focal length determination. Also, advanced Interference techniques such as Talbot, Moire, Digital Speckle, Zygo and Joint Fourier Transform were used for focal length measurements. These techniques require more elaborate setups and difficult to implement, especially for microlenses. Recently a power meter was used to find the focal length of an unknown lens. Most of the techniques mentioned above proof to be not simple for microlens characterization. The z-scan technique has been implemented, for quite sometimes, to characterize the third-order effects of a nonlinear optical material. The z-scan provides information on both the sign and magnitude of the non-linear refractive index and offer advantage of simplicity. We have used a regular lens to collimate and focus light unto the lens under test. By scanning the lens under test and measuring the on-axis intensity, one can find the focal length. This is because the on-axis intensity is proportional to the phase of the lens and therefore the focal length. In the case of an adaptive lens with its focal length is a function of the applied voltage, the scanning occurs for each voltage value that will correspond to the on-axis refractive index change and therefore the far field on-axis intensity. This described technique above is easy to implement and can achieve good accuracy due to the inherent sensitivity of the z-scan.

  7. Assessing atrophy measurement techniques in dementia: Results from the MIRIAD atrophy challenge

    Science.gov (United States)

    Cash, David M.; Frost, Chris; Iheme, Leonardo O.; Ünay, Devrim; Kandemir, Melek; Fripp, Jurgen; Salvado, Olivier; Bourgeat, Pierrick; Reuter, Martin; Fischl, Bruce; Lorenzi, Marco; Frisoni, Giovanni B.; Pennec, Xavier; Pierson, Ronald K.; Gunter, Jeffrey L.; Senjem, Matthew L.; Jack, Clifford R.; Guizard, Nicolas; Fonov, Vladimir S.; Collins, D. Louis; Modat, Marc; Cardoso, M. Jorge; Leung, Kelvin K.; Wang, Hongzhi; Das, Sandhitsu R.; Yushkevich, Paul A.; Malone, Ian B.; Fox, Nick C.; Schott, Jonathan M.; Ourselin, Sebastien

    2015-01-01

    Structural MRI is widely used for investigating brain atrophy in many neurodegenerative disorders, with several research groups developing and publishing techniques to provide quantitative assessments of this longitudinal change. Often techniques are compared through computation of required sample size estimates for future clinical trials. However interpretation of such comparisons is rendered complex because, despite using the same publicly available cohorts, the various techniques have been assessed with different data exclusions and different statistical analysis models. We created the MIRIAD atrophy challenge in order to test various capabilities of atrophy measurement techniques. The data consisted of 69 subjects (46 Alzheimer's disease, 23 control) who were scanned multiple (up to twelve) times at nine visits over a follow-up period of one to two years, resulting in 708 total image sets. Nine participating groups from 6 countries completed the challenge by providing volumetric measurements of key structures (whole brain, lateral ventricle, left and right hippocampi) for each dataset and atrophy measurements of these structures for each time point pair (both forward and backward) of a given subject. From these results, we formally compared techniques using exactly the same dataset. First, we assessed the repeatability of each technique using rates obtained from short intervals where no measurable atrophy is expected. For those measures that provided direct measures of atrophy between pairs of images, we also assessed symmetry and transitivity. Then, we performed a statistical analysis in a consistent manner using linear mixed effect models. The models, one for repeated measures of volume made at multiple time-points and a second for repeated “direct” measures of change in brain volume, appropriately allowed for the correlation between measures made on the same subject and were shown to fit the data well. From these models, we obtained estimates of the

  8. Assessing atrophy measurement techniques in dementia: Results from the MIRIAD atrophy challenge.

    Science.gov (United States)

    Cash, David M; Frost, Chris; Iheme, Leonardo O; Ünay, Devrim; Kandemir, Melek; Fripp, Jurgen; Salvado, Olivier; Bourgeat, Pierrick; Reuter, Martin; Fischl, Bruce; Lorenzi, Marco; Frisoni, Giovanni B; Pennec, Xavier; Pierson, Ronald K; Gunter, Jeffrey L; Senjem, Matthew L; Jack, Clifford R; Guizard, Nicolas; Fonov, Vladimir S; Collins, D Louis; Modat, Marc; Cardoso, M Jorge; Leung, Kelvin K; Wang, Hongzhi; Das, Sandhitsu R; Yushkevich, Paul A; Malone, Ian B; Fox, Nick C; Schott, Jonathan M; Ourselin, Sebastien

    2015-12-01

    Structural MRI is widely used for investigating brain atrophy in many neurodegenerative disorders, with several research groups developing and publishing techniques to provide quantitative assessments of this longitudinal change. Often techniques are compared through computation of required sample size estimates for future clinical trials. However interpretation of such comparisons is rendered complex because, despite using the same publicly available cohorts, the various techniques have been assessed with different data exclusions and different statistical analysis models. We created the MIRIAD atrophy challenge in order to test various capabilities of atrophy measurement techniques. The data consisted of 69 subjects (46 Alzheimer's disease, 23 control) who were scanned multiple (up to twelve) times at nine visits over a follow-up period of one to two years, resulting in 708 total image sets. Nine participating groups from 6 countries completed the challenge by providing volumetric measurements of key structures (whole brain, lateral ventricle, left and right hippocampi) for each dataset and atrophy measurements of these structures for each time point pair (both forward and backward) of a given subject. From these results, we formally compared techniques using exactly the same dataset. First, we assessed the repeatability of each technique using rates obtained from short intervals where no measurable atrophy is expected. For those measures that provided direct measures of atrophy between pairs of images, we also assessed symmetry and transitivity. Then, we performed a statistical analysis in a consistent manner using linear mixed effect models. The models, one for repeated measures of volume made at multiple time-points and a second for repeated "direct" measures of change in brain volume, appropriately allowed for the correlation between measures made on the same subject and were shown to fit the data well. From these models, we obtained estimates of the

  9. International workshop on measuring techniques for liquid metal flows (MTLM). Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Gerbeth, G.; Eckert, S. [eds.

    1999-11-01

    The international workshop on 'Measuring techniques in liquid metal flows' (MTLM workshop) was organised in frame of the Dresden 'Innovationskolleg Magnetofluiddynamik'. The subject of the MTLM workshop was limited to methods to determine physical flow quantities such as velocity, pressure, void fraction, inclusion properties, crystallisation fronts etc. The present proceedings contain abstracts and viewgraphs of the oral presentations. During the last decades numerical simulations have become an important tool in industry and research to study the structure of flows and the properties of heat and mass transfer. However, in case of liquid metal flows there exists a significant problem to validate the codes with experimental data due to the lack of available measuring techniques. Due to the material properties (opaque, hot, chemical aggressive) the measurement of flow quantities is much more delicate in liquid metals compared to ordinary water flows. The generalisation of results obtained by means of water models to real liquid metal flows has often to be considered as difficult due to the problems to meet the actual values of n0n-dimensional flow parameters (Re, Pr, Gr, Ha, etc.). Moreover, a strong need has to be noted to make measuring techniques available tomonitor and to control flow processes in real industrial facilities. The objectives of the MTLM workshop were to: Review of existing information on a available techniques and experiences about the use in liquid metal flows, initiate a discussion between developers and potential users with respect to the actual need of information about the flow structure as well as the capabilities of existing and developing measuring techniques. Explore opportunities for co-operative R and D projects to expedite new developments and results, to share expertise and resources. (orig.)

  10. Single-step spatial rotation error separation technique for the ultraprecision measurement of surface profiles.

    Science.gov (United States)

    Hou, Maosheng; Qiu, Lirong; Zhao, Weiqian; Wang, Fan; Liu, Entao; Ji, Lin

    2014-01-20

    To improve the measurement accuracy of the profilometer for large optical surfaces, a new single-step spatial rotation error separation technique (SSEST) is proposed to separate the surface profile error and spindle spatial rotation error, and a novel SSEST-based system for surface profile measurement is developed. In the process of separation, two sets of measured results at the ith measurement circle are obtained before and after the rotation of error separation table, the surface profile error and spatial rotation error of spindle can be determined using discrete Fourier-transform and harmonic analysis. Theoretical analyses and experimental results indicate that SSEST can accurately separate spatial rotation error of spindle from the measured surface profile results within the range of 1-100 upr and improve the accuracy of surface profile measurements.

  11. Measurements of the subcriticality using advanced technique of shooting source during operation of NPP reactors

    Science.gov (United States)

    Lebedev, G. V.; Petrov, V. V.; Bobylyov, V. T.; Butov, R. I.; Zhukov, A. M.; Sladkov, A. A.

    2014-12-01

    According to the rules of nuclear safety, the measurements of the subcriticality of reactors should be carried out in the process of performing nuclear hazardous operations. An advanced technique of shooting source of neutrons is proposed to meet this requirement. As such a source, a pulsed neutron source (PNS) is used. In order to realize this technique, it is recommended to enable a PNS with a frequency of 1-20 Hz. The PNS is stopped after achieving a steady-state (on average) number of neutrons in the reactor volume. The change in the number of neutrons in the reactor volume is measured in time with an interval of discreteness of ˜0.1 s. The results of these measurements with the application of a system of point-kinetics equations are used in order to calculate the sought subcriticality. The basic idea of the proposed technique used to measure the subcriticality is elaborated in a series of experiments on the Kvant assembly. The conditions which should be implemented in order to obtain a positive result of measurements are formulated. A block diagram of the basic version of the experimental setup is presented, whose main element is a pulsed neutron generator.

  12. Measurement of bubble velocity using Capacitively Coupled Contactless Conductivity Detection (C4D) technique

    Institute of Scientific and Technical Information of China (English)

    Baoliang Wang; Ying Zhou; Haifeng Ji; Zhiyao Huang; Haiqing Li

    2013-01-01

    The feasibility of applying Capacitively Coupled Contactless Conductivity Detection (C4D) technique to measurement of bubble velocity in gas-liquid two-phase flow in millimeter-scale pipe is investigated.And,a new method,which combines the C4D technique and the principle of cross-correlation velocity measurement,is proposed for the measurement of bubble velocity.This research includes two parts.First,based on the principle of C4D,a new five-electrode C4D sensor is developed.Then,with two conductivity signals obtained by the C4D sensor,the velocity measurement of bubble is implemented according to the principle of cross-correlation.The research results indicate that the C4D technique is highly effective and anticipates a broad potential in the field of two-phase flow.Experimental results show that the fiveelectrode C4D sensor is suitable for measuring the velocity of single bubbles with a relative error of less than 5%.

  13. Three-dimensional surface measurement based on the projected defocused pattern technique using imaging fiber optics

    Science.gov (United States)

    Parra Escamilla, Geliztle A.; Kobayashi, Fumio; Otani, Yukitoshi

    2017-05-01

    We present a three-dimensional surface measurement system using imaging fiber endoscope and the measurement is based on the focus technique in uniaxial configuration. The surface height variation of the sample is retrieved by taking into account the contrast modulation change obtained from a projected fringe pattern on the sample. The technique takes into account the defocus change of the fringe pattern due to the height variation of the sample and by a Gaussian fitting process the height reconstruction can be retrieved. A baseline signal procedure was implemented to remove back reflection light coming from the two fiber-surfaces (inlet and outlet) and also a Fourier transform filter was used to remove the pixelated appearance of the images. The depth range of the system is 1.1 mm and a lateral range of 2 mm by 2 mm. The novelties of the implementation are that the system uses the same imaging fiber as illumination and measurement and offers the advantage of the transportability to the measurement to a confined space having potential application on medical or industrial endoscopes systems. We demonstrate the technique by showing the surface profile of a measured object.

  14. Measurement of initial absorption of fused silica at 193nm using laser induced deflection technique (LID)

    Science.gov (United States)

    Schönfeld, Dörte; Klett, Ursula; Mühlig, Christian; Thomas, Stephan

    2008-01-01

    The ongoing development in microlithography towards further miniaturization of structures creates a strong demand for lens material with nearly ideal optical properties. Beside the highly demanding requirements on homogeneity and stress induced birefringence (SIB), low absorption is a key factor. Even a small absorption is associated with a temperature increase and results in thermally induced local variations of refractive index and SIB. This could affect the achievable resolution of the lithographic process. The total absorption of the material is composed of initial absorption and of absorption induced during irradiation. Thus, the optimization of both improves the lifetime of the material. In principal, it is possible to measure transmission and scattering with a suitable spectrometer assembly and calculate absorption from them. However, owing to the influence of sample surfaces and errors of measurement, these methods usually do not provide satisfactory results for highly light-transmissive fused silica. Therefore, it is most desirable to find a technique that is capable of directly measuring absorption coefficients in the range of (1...10)•10 -4 cm -1 (base 10) directly. We report our first results for fused silica achieved with the LID technique. Besides a fused silica grade designed for 193 nm applications, grades with higher absorption at 193 nm were measured to test the LID technique. A special focus was set on the possibility of measuring initial absorption without the influence of degradation effects.

  15. Adaptive digital fringe projection technique for high dynamic range three-dimensional shape measurement.

    Science.gov (United States)

    Lin, Hui; Gao, Jian; Mei, Qing; He, Yunbo; Liu, Junxiu; Wang, Xingjin

    2016-04-04

    It is a challenge for any optical method to measure objects with a large range of reflectivity variation across the surface. Image saturation results in incorrect intensities in captured fringe pattern images, leading to phase and measurement errors. This paper presents a new adaptive digital fringe projection technique which avoids image saturation and has a high signal to noise ratio (SNR) in the three-dimensional (3-D) shape measurement of objects that has a large range of reflectivity variation across the surface. Compared to previous high dynamic range 3-D scan methods using many exposures and fringe pattern projections, which consumes a lot of time, the proposed technique uses only two preliminary steps of fringe pattern projection and image capture to generate the adapted fringe patterns, by adaptively adjusting the pixel-wise intensity of the projected fringe patterns based on the saturated pixels in the captured images of the surface being measured. For the bright regions due to high surface reflectivity and high illumination by the ambient light and surfaces interreflections, the projected intensity is reduced just to be low enough to avoid image saturation. Simultaneously, the maximum intensity of 255 is used for those dark regions with low surface reflectivity to maintain high SNR. Our experiments demonstrate that the proposed technique can achieve higher 3-D measurement accuracy across a surface with a large range of reflectivity variation.

  16. A laser-induced fluorescence measurement technique for obtaining neutral hydrogen densities in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Yao, X.Z.; Yang, T.F.; Chang-Diaz, F.R. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1995-09-01

    The resonance fluorescence of neutral hydrogen illuminated by {ital H}{sub {alpha}} radiation has been used as a technique for the spatially and temporally resolved density measurements of neutral hydrogen in high temperature plasmas, such as in the tokamak and magnetic mirror plasma fusion devices. The fluorescence signal, usually very weak and buried in the background of stray laser light and {ital H}{sub {alpha}} emission, is very difficult to extract and its measurements are inaccurate. This paper discusses the improvement of the signal extraction using two optical path laser-induced fluorescence (LIF) methods. One optical path carries the fluorescence signal and the background (the stray laser light and {ital H}{sub {alpha}} emission), whereas the other path carries only the background signal. By combining these two signals, a clean fluorescence signal can be isolated by subtracting out the background using a differential amplifier. The measurement is obtained instantaneously from these two signals which are taken simultaneously in one pulse rather than being extracted from two separate spectra taken in two sequential pulses (double pulses). This method, therefore, makes a significant improvement on the double pulse technique in terms of the accuracy of the measurement and the time resolution. Using this LIF technique the measurement of the neutral density profile in the exhaust of a tandem mirror plasma propulsion device is obtained and presented. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  17. Application of real-time digitization techniques in beam measurement for accelerators

    Science.gov (United States)

    Zhao, Lei; Zhan, Lin-Song; Gao, Xing-Shun; Liu, Shu-Bin; An, Qi

    2016-04-01

    Beam measurement is very important for accelerators. In this paper, modern digital beam measurement techniques based on IQ (In-phase & Quadrature-phase) analysis are discussed. Based on this method and high-speed high-resolution analog-to-digital conversion, we have completed three beam measurement electronics systems designed for the China Spallation Neutron Source (CSNS), Shanghai Synchrotron Radiation Facility (SSRF), and Accelerator Driven Sub-critical system (ADS). Core techniques of hardware design and real-time system calibration are discussed, and performance test results of these three instruments are also presented. Supported by National Natural Science Foundation of China (11205153, 10875119), Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), and the Fundamental Research Funds for the Central Universities (WK2030040029),and the CAS Center for Excellence in Particle Physics (CCEPP).

  18. Continuous measurement of cardiac output with the use of stochastic system identification techniques.

    Science.gov (United States)

    Yelderman, M

    1990-10-01

    The limitations of developing a technique to measure cardiac output continuously are given. Logical explanations are provided for the economic, technical, and physiologic benefits of a stochastic system identification technique for measuring cardiac output. Heat is supplied by a catheter-mounted filament driven according to a pseudorandom binary sequence. Volumetric fluid flow is derived by a cross-correlation algorithm written in the C language. In vitro validation is performed with water in a flow bench. The computed flow (y) compared with the in-line-measured flow (x) yields the linear regression y = 1.024x - 0.157 (r = 0.99). The average coefficient of variation is less than 2% over a volumetric fluid flow range of 2 to 10 L/min.

  19. Measurements of aerosol fluxes to Speulder forest using a micrometeorological technique

    DEFF Research Database (Denmark)

    Gallagher, M.W.; Beswick, K.M.; Duyzer, J.

    1997-01-01

    to a forest and show that they are large, typically 1 cm s(-1) or more. We compare the measurements with literature values obtained by throughfall and related techniques. The results, rather than being irreconcilable, show a clear and consistent behaviour in deposition velocity across the aerosol size......It has often been stated that micrometeorological and throughfall measurements of dry deposition differ by an order of magnitude with the results being highly variable and difficult to interpret or reconcile. We present measurements by the eddy correlation method of sub-micron aerosol deposition...... spectrum, despite the very different techniques involved. There would appear to be a contradiction with previously assumed model predictions of aerosol deposition Velocity to forests and rough vegetated surfaces particularly for particles in the size range 0.1-1.0 mu m where collection efficiencies appear...

  20. A revised uncertainty budget for measuring the Boltzmann constant using the Doppler Broadening Technique on ammonia

    CERN Document Server

    Lemarchand, Cyril; Sow, Papa Lat Tabara; Triki, Meriam; Tokunaga, Sean K; Briaudeau, Stephan; Chardonnet, Christian; Darquié, Benoît; Daussy, Christophe

    2013-01-01

    We report on our on-going effort to measure the Boltzmann constant, kB, using the Doppler Broadening Technique. The main systematic effects affecting the measurement are discussed. A revised error budget is presented in which the global uncertainty on systematic effects is reduced to 2.3 ppm. This corresponds to a reduction of more than one order of magnitude compared to our previous Boltzmann constant measurement. Means to reach a determination of kB at the part per million accuracy level are outlined.

  1. Advanced Failure Determination Measurement Techniques Used in Thermal Fatigue Life Testing of Electronic Packaging

    Science.gov (United States)

    Wallace, A. P.; Cornford, S. L.; Gross, M. A.

    1996-01-01

    Thermal fatigue life testing of various electronic packaging technologies is being performed by the Reliability Technology Group at the Jet Propulsion Laboratory. These testing efforts are in progress to improve uderstanding of the reliability issues associated with low volume packaging technologies for space applications and to develop qualification and acceptance approaches for these technologies. The work described here outlines the electrical failure detection techniques used during testing by documenting the circuits and components used to make these measurements, the sensitivity of the measurements, and the applicability of each specific measurement.

  2. Cavity ring-down technique for measurement of reflectivity of high reflectivity mirrors with high accuracy

    Indian Academy of Sciences (India)

    G Sridhar; Sandeep K Agarwalla; Sunita Singh; L M Gantayet

    2010-12-01

    A simple, accurate and reliable method for measuring the reflectivity of laser-grade mirrors ( > 99.5 %) based on cavity ring-down (CRD) technique has been success-fully demonstrated in our laboratory using a pulsed Nd:YAG laser. A fast photomultiplier tube with an oscilloscope was used to detect and analyse the CRD signal. The cavity decay times were measured for three cavities formed by a combination of three mirror pairs. The absolute reflectivities 1, 2, 3 were determined to be 99.94%, 99.63%, 99.52% at normal incidence. The reflectivity of mirrors is measured to an accuracy of 0.01%.

  3. Thickness measurement of multi-layer conductive coatings using multifrequency eddy current techniques

    Science.gov (United States)

    Zhang, Dejun; Yu, Yating; Lai, Chao; Tian, Guiyun

    2016-07-01

    To ensure the key structural performance in high-temperature and high-stress environments, thermal barrier coatings (TBCs) are often adopted in engineering. The thickness of these multi-layer conductive coatings is an important quality indicator. In order to measure the thickness of multi-layer conductive coatings, a new measurement approach is presented using eddy current testing techniques, and then, an inversion algorithm is proposed and proved efficient and applicable, of which the maximum experimental relative error is within 10%. Therefore, the new approach can be effectively applied to thickness measurement of multi-layer conductive coatings such as TBCs.

  4. A simple technique for high resolution time domain phase noise measurement

    Science.gov (United States)

    Reinhardt, V. S.; Donahoe, T.

    1977-01-01

    A new time domain phase comparator is described. The device uses a novel technique to allow time domain phase measurements to be made with period and time interval counters without the use of offset reference oscillators. The device uses a single reference oscillator and allows measurements with a phase resolution greater than the noise floor of the reference. Data is presented showing a phase resolution of 0.02ps at 5 MHz with a crystal reference. The device has application in measuring the phase stability of systems where approximate phase quadrature can be maintained.

  5. Comparison of noninvasive blood pressure measurement techniques via the coccygeal artery in anesthetized cheetahs (Acinonyx jubatus).

    Science.gov (United States)

    Sadler, Ryan A; Hall, Natalie H; Kass, Philip H; Citino, Scott B

    2013-12-01

    Two indirect blood pressure measurement techniques, Doppler (DOP) sphygmomanometry and oscillometry, applied at the ventral coccygeal artery were compared with simultaneous direct blood pressure measurements at the dorsal pedal artery in 10 anesthetized, captive cheetahs (Acinonyx jubatus). The DOP method was moderately accurate, with relatively little bias (mean difference 3.8 mmHg) and 88.6% of the DOP systolic arterial pressure measurements being within 10 mmHg of the direct systolic arterial measurement. With the oscillometric (OM) method, 89.2% of the mean arterial pressure measurements were within 10 mmHg of the direct measurement and had the least bias (mean difference 2.3 mmHg), 80.7% of the systolic measurements were within 10 mmHg of the direct measurement and had the second least bias (mean difference 2.3 mmHg), and 59% of the diastolic measurements were within 10 mmHg of the direct measurement and had significant bias (mean difference 7.3 mmHg). However, DOP showed relatively poor precision (SD 11.2 mmHg) compared with OM systolic (SD 8.0 mmHg), diastolic (SD 8.6 mmHg), and mean (SD 5.7 mmHg). Both techniques showed a linear relationship with the direct technique measurements over a wide range of blood pressures. The DOP method tended to underestimate systolic measurements below 160 mmHg and overestimate systolic measurements above 160 mmHg. The OM method tended to underestimate mean pressures below 160 mm Hg, overestimate mean pressures above 160 mmHg, underestimate systolic pressures below 170 mmHg, overestimate systolic pressures above 170 mmHg, and underestimate diastolic pressures throughout the measured blood pressure range. Indirect blood pressure measurement using the ventral coccygeal artery, particularly when using an OM device for mean and systolic arterial pressure, may be useful in the clinical assessment of cheetahs when monitoring trends over time, but caution should be taken when interpreting individual values.

  6. Pressure Autoregulation Measurement Techniques in Adult TBI, Part II: A Scoping Review of Continuous Methods.

    Science.gov (United States)

    Zeiler, Frederick Adam; Donnelly, Joseph; Calviello, Leanne; Smieleweski, Peter; Menon, David; Czosnyka, Marek

    2017-07-12

    To perform systematically a scoping review of the literature on commonly described continuous autoregulation measurement techniques in adult TBI. The goal was to provide an overview of methodology and comprehensive reference library of the available literature for each technique. Five separate small systematic reviews were conducted for each of the continuous techniques: pressure reactivity index (PRx), laser Doppler flowmetry (LDF), near infrared spectroscopy (NIRS) techniques, brain tissue oxygen tension (PbtO2), and thermal diffusion (TD) techniques. Articles from MEDLINE, BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library (inception to December 2016) and reference lists of relevant articles were searched. A two-tier filter of references was conducted. The literature base identified from the individual searches was limited, except for PRx. The total number of articles utilizing each of the 5 searched techniques for continuous autoregulation in adult TBI were: PRx (28), LDF (4), NIRS (9), PbtO2 (10), and TD (8). All continuous techniques described in adult TBI are based on moving correlation coefficients. The premise behind the calculation of these moving correlation coefficients focuses on the impact of slow fluctuations in either MAP or CPP on some indirect measure of CBF, such as: intracranial pressure (ICP), LDF, NIRS signals, PbtO2 or TD CBF. The thought is the correlation between a hemodynamic driving factor, such as MAP or CPP, and a surrogate for CBF or cerebral perfusion sheds insight on the state of cerebral autoregulation. Both PRx and NIRS indices were validated experimentally against 'golden standard' static autoregulatory curve (Lassen curve) at least around lower threshold of autoregulation. PRx has the largest literature base supporting the association with patient outcome. Various methods of continuous autoregulation assessment are described within the adult TBI literature. Many studies exist on these various indices, suggesting an

  7. Development of the laser absorption radiation thermometry technique to measure thermal diffusivity in addition to temperature

    Science.gov (United States)

    Levick, Andrew; Lobato, Killian; Edwards, Gordon

    2003-01-01

    A comparative technique based on photothermal radiometry has been developed to measure thermal diffusivity of semi-infinite targets with arbitrary geometry. The technique exploits the principle that the frequency response of the temperature modulation induced by a periodic modulated heating source (in this case a laser spot) scales with thermal diffusivity. To demonstrate this technique, a photothermal radiometer has been developed, which detects modulated thermal radiance at a wavelength of 2 μm due to a small temperature modulation induced on the target surface by a modulated erbium fiber laser of power 1 W. Two frequency responses were measured for platinum and oxidized Inconel 600 targets (the frequency response is a scan of the amplitude of the modulated thermal radiance over laser modulation frequency). Scaling the two responses with respect to frequency gives a ratio of thermal diffusivities Dplatinum/DInconel of 4.45(33) which compares with a literature value of 4.46(50). The aim is to combine this technique with laser absorption radiation thermometry to produce multithermal property instrument for measuring "industrial" targets.

  8. Advancement of an Infra-Red Technique for Whole-Field Concentration Measurements in Fluidized Beds

    Science.gov (United States)

    Medrano, Jose A.; de Nooijer, Niek C. A.; Gallucci, Fausto; van Sint Annaland, Martin

    2016-01-01

    For a better understanding and description of the mass transport phenomena in dense multiphase gas-solids systems such as fluidized bed reactors, detailed and quantitative experimental data on the concentration profiles is required, which demands advanced non-invasive concentration monitoring techniques with a high spatial and temporal resolution. A novel technique based on the selective detection of a gas component in a gas mixture using infra-red properties has been further developed. The first stage development was carried out using a very small sapphire reactor and CO2 as tracer gas. Although the measuring principle was demonstrated, the real application was hindered by the small reactor dimensions related to the high costs and difficult handling of large sapphire plates. In this study, a new system has been developed, that allows working at much larger scales and yet with higher resolution. In the new system, propane is used as tracer gas and quartz as reactor material. In this study, a thorough optimization and calibration of the technique is presented which is subsequently applied for whole-field measurements with high temporal resolution. The developed technique allows the use of a relatively inexpensive configuration for the measurement of detailed concentration fields and can be applied to a large variety of important chemical engineering topics. PMID:26927127

  9. Reproducibility of techniques using Archimedes' principle in measuring cancellous bone volume.

    Science.gov (United States)

    Zou, L; Bloebaum, R D; Bachus, K N

    1997-01-01

    Researchers have been interested in developing techniques to accurately and reproducibly measure the volume fraction of cancellous bone. Historically bone researchers have used Archimedes' principle with water to measure the volume fraction of cancellous bone. Preliminary results in our lab suggested that the calibrated water technique did not provide reproducible results. Because of this difficulty, it was decided to compare the conventional water method to a water with surfactant and a helium method using a micropycnometer. The water/surfactant and the helium methods were attempts to improve the fluid penetration into the small voids present in the cancellous bone structure. In order to compare the reproducibility of the new methods with the conventional water method, 16 cancellous bone specimens were obtained from femoral condyles of human and greyhound dog femora. The volume fraction measurements on each specimen were repeated three times with all three techniques. The results showed that the helium displacement method was more than an order of magnitudes more reproducible than the two other water methods (p < 0.05). Statistical analysis also showed that the conventional water method produced the lowest reproducibility (p < 0.05). The data from this study indicate that the helium displacement technique is a very useful, rapid and reproducible tool for quantitatively characterizing anisotropic porous tissue structures such as cancellous bone.

  10. Advancement of an Infra-Red Technique for Whole-Field Concentration Measurements in Fluidized Beds

    Directory of Open Access Journals (Sweden)

    Jose A. Medrano

    2016-02-01

    Full Text Available For a better understanding and description of the mass transport phenomena in dense multiphase gas-solids systems such as fluidized bed reactors, detailed and quantitative experimental data on the concentration profiles is required, which demands advanced non-invasive concentration monitoring techniques with a high spatial and temporal resolution. A novel technique based on the selective detection of a gas component in a gas mixture using infra-red properties has been further developed. The first stage development was carried out using a very small sapphire reactor and CO2 as tracer gas. Although the measuring principle was demonstrated, the real application was hindered by the small reactor dimensions related to the high costs and difficult handling of large sapphire plates. In this study, a new system has been developed, that allows working at much larger scales and yet with higher resolution. In the new system, propane is used as tracer gas and quartz as reactor material. In this study, a thorough optimization and calibration of the technique is presented which is subsequently applied for whole-field measurements with high temporal resolution. The developed technique allows the use of a relatively inexpensive configuration for the measurement of detailed concentration fields and can be applied to a large variety of important chemical engineering topics.

  11. Techniques, processes, and measures for software safety and reliability. Version 3.0

    Energy Technology Data Exchange (ETDEWEB)

    Sparkman, D

    1992-05-30

    The purpose of this report is to provide a detailed survey of current recommended practices and measurement techniques for the development of reliable and safe software-based systems. This report is intended to assist the United States Nuclear Reaction Regulation (NRR) in determining the importance and maturity of the available techniques and in assessing the relevance of individual standards for application to instrumentation and control systems in nuclear power generating stations. Lawrence Livermore National Laboratory (LLNL) provides technical support for the Instrumentation and Control System Branch (ICSB) of NRRin advanced instrumentation and control systems, distributed digital systems, software reliability, and the application of verificafion and validafion for the development of software.

  12. Comparison of ocular biometry measurements by applanation and immersion A-scan techniques.

    Science.gov (United States)

    Ademola-Popoola, Dupe S; Nzeh, Donald A; Saka, Sadiat E; Olokoba, Lateefat B; Obajolowo, Tokunbo S

    2015-01-01

    The study compared ocular biometry values using applanation and immersion techniques to determine the most applicable method for our tertiary training centre where personnel with different levels of experience and expertise in biometry take measurements used in calculation of required intraocular lens before cataract surgery. The study was a prospective cross-sectional comparative study of different techniques of ocular biometry from diagnostic equipment (biometry probe 10 MHz Sonomed(®) A-scan (PACSCAN 300A, USA). Measurement variables were obtained among children and adults undergoing cataract surgery. Scleral (Prager) shell was used for the immersion technique followed by the contact technique by the same examiner. The biometry values of 92 eyes of 92 adult were taken. Their ages ranged from 18 to 95 years with a mean of 64.7 (SD ± 12.9) years. There were 55 (59.8%) males and 37 (40.2%) females, with a male to female ratio of 1.5:1. Average axial length (22.0-24.4 mm) eyes were the most common eyes measured in 75 (81.5%) of the cases. The means of the axial lengths biometry values with immersion and contact technique were 23.66(±1.36) and 23.46 mm (±1.46); the axial length differences was 0.2 ± 0.26 mm (range 0.0-0.94 mm) and statistically significant (95% CI of the Difference 0.15 to 0.26, p = 0.000). The Standard deviation SD (mm) of Individual Eye Axial Length showed a mean of 0.03 ± 0.04 (0.0-0.3) mm for immersion and for contact technique 0.14 ± 0.12(0.0-0.6)mm. There was a significant difference in ocular biometry measurement with the contact and immersion ultrasound techniques. The immersion technique had better repeatability, thus it is ideal in a training hospital setting in a typical in sub-Saharan Africa who have limited resources to employ a dedicated person to do biometry; and where the different operators of A-scan machines have different levels of experience and expertise.

  13. Thermal Warpage Measurement of Electronic Packages by Shadow Moiré with Phase Stepping Technique

    Institute of Scientific and Technical Information of China (English)

    Yinyan Wang

    2011-01-01

    Phase-stepping technique is applied to the analysis of fringe patterns of shadow moiré of electronic packages.Sensitivity of the fringe pattern analysis is demonstrated to be significantly increased. Thermally induced warpage of electronic packages is successfully measured in real-time as the sample is driven through a simulated reflow process.The paper discusses the technique of phase stepping,noise filtering and its application to the shadow moiré method.Applications of the technology are presented.

  14. New autocorrelation technique for the IR FEL optical pulse width measurements

    Energy Technology Data Exchange (ETDEWEB)

    Amirmadhi, F.; Brau, K.A.; Becker, C. [Vanderbilt Univ., Nashville, TN (United States)] [and others

    1995-12-31

    We have developed a new technique for the autocorrelation measurement of optical pulse width at the Vanderbilt University FEL center. This method is based on nonlinear absorption and transmission characteristics of semiconductors such as Ge, Te and InAs suitable for the wavelength range from 2 to over 6 microns. This approach, aside being simple and low cost, removes the phase matching condition that is generally required for the standard frequency doubling technique and covers a greater wavelength range per nonlinear material. In this paper we will describe the apparatus, explain the principal mechanism involved and compare data which have been acquired with both frequency doubling and two-photon absorption.

  15. Precision of lumbar intervertebral measurements: does a computer-assisted technique improve reliability?

    Science.gov (United States)

    Pearson, Adam M; Spratt, Kevin F; Genuario, James; McGough, William; Kosman, Katherine; Lurie, Jon; Sengupta, Dilip K

    2011-04-01

    Comparison of intra- and interobserver reliability of digitized manual and computer-assisted intervertebral motion measurements and classification of "instability." To determine if computer-assisted measurement of lumbar intervertebral motion on flexion-extension radiographs improves reliability compared with digitized manual measurements. Many studies have questioned the reliability of manual intervertebral measurements, although few have compared the reliability of computer-assisted and manual measurements on lumbar flexion-extension radiographs. Intervertebral rotation, anterior-posterior (AP) translation, and change in anterior and posterior disc height were measured with a digitized manual technique by three physicians and by three other observers using computer-assisted quantitative motion analysis (QMA) software. Each observer measured 30 sets of digital flexion-extension radiographs (L1-S1) twice. Shrout-Fleiss intraclass correlation coefficients for intra- and interobserver reliabilities were computed. The stability of each level was also classified (instability defined as >4 mm AP translation or 10° rotation), and the intra- and interobserver reliabilities of the two methods were compared using adjusted percent agreement (APA). Intraobserver reliability intraclass correlation coefficients were substantially higher for the QMA technique THAN the digitized manual technique across all measurements: rotation 0.997 versus 0.870, AP translation 0.959 versus 0.557, change in anterior disc height 0.962 versus 0.770, and change in posterior disc height 0.951 versus 0.283. The same pattern was observed for interobserver reliability (rotation 0.962 vs. 0.693, AP translation 0.862 vs. 0.151, change in anterior disc height 0.862 vs. 0.373, and change in posterior disc height 0.730 vs. 0.300). The QMA technique was also more reliable for the classification of "instability." Intraobserver APAs ranged from 87 to 97% for QMA versus 60% to 73% for digitized manual

  16. A lithium depth-marker technique for rapid erosion and deposition measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, R.M., E-mail: rsulli@psfc.mit.edu; Pang, A.; Martinez-Sanchez, M.; Whyte, D.G.

    2014-01-15

    Highlights: • Rutherford backscattering spectrometry (RBS) to determine the change in depth. • Rutherford backscattering spectrometry (RBS) to determine the change in depth. • Rutherford backscattering spectrometry (RBS) to determine the change in depth. -- Abstract: A novel, high-resolution technique has been developed for the measurement of erosion and deposition in solid material surfaces. The technique uses a combination of nuclear reaction analysis (NRA) and Rutherford backscattering spectrometry (RBS) to determine the change in depth of a previously implanted marker layer consisting of {sup 7}Li. A scoping study shows that {sup 7}Li is an ideal marker candidate due to a high Q (∼18 MeV) nuclear reaction, {sup 7}Li(p,α){sup 4}He. Net erosion or deposition is measured by NRA of modified alpha energy passing through the bulk material. The reaction’s high cross-section provides for the fast time resolution needed to measure erosion from high flux plasmas, and a highly penetrating proton beam provides for a large range of erosion/deposition measurements. Additionally, the implantation of low-Z Li leads to relatively low vacancy concentrations in the solid material due to implantation. This technique thus provides greater assurance that the measured erosion rate is indicative of the solid material: due to both the low vacancy production and the fact that no films or deposits are involved. Validation was performed by comparing the measured and predicted amount of erosion based on previously measured sputtering yields; the two were found to agree, within the uncertainty of the experiment. The depth resolution of the techniques is ∼60 nm at a net erosion depth of about 1 μm. The benefits of this technique are summarized as: short time scales (minutes) to obtain results, the marker layer can be used in any solid material, greater assurance that the measured erosion is indicative of the unperturbed solid material, and the continuous monitoring of the

  17. Initial development of an NIR strain measurement technique in brittle geo-materials

    Science.gov (United States)

    Butcher, Emily; Gibson, Andrew; Benson, Philip

    2016-04-01

    Visible-Near Infrared Spectroscopy (VIS-NIR) is a technique developed for the non-contact measurement of compositional characteristics of surfaces. The technique is rapid, sensitive to change in surface topology and has found applications ranging from planetary geology, soil science, pharmacy to materials testing. The technique has also been used in a limited fashion to measure strain changes in rocks and minerals (Ord and Hobbs 1986). However, there have been few quantitative studies linking such changes in material strains (and other rock physics parameters) to the resulting VIS-NIT signature. This research seeks to determine whether improvements in VIS-NIR equipment means that such a technique is a viable method to measure strains in rock via this remote (non-contact) method. We report new experiments carried out using 40 mm Brazilian Tensile discs of Carrera Marble and Darley Dale Sandstone using an Instron 600LX in the University of Portsmouth Rock Mechanics Laboratory. The tensile test was selected for this experiment as the sample shape and sensor arrangements allow access to a 'flat' surface area throughout the test, allowing surface measurements to be continuously taken whilst the discs are strained to failure. An ASD Labspec 5000 with 25 mm foreoptic was used to collect reflectance spectra in the range 350-2500 nm during each tensile test. Results from Carrera Marble experiments show that reflectance at 2050 nm negatively correlates (by polynomial regression) with axial strain between 0.05-0.5%, with r2 of 0.99. Results from Darley Dale Sandstone data show that reflectance at 1970 nm positively correlates with axial deformation between 0.05-0.5%, with r2 of 0.98. Initial analyses suggests that the VIS-NIR possesses an output that scales in a quantifiable manner with rock strain, and shows promise as a technique for strain measurement. The method has particular application for allowing our laboratory measurements to "ground truth" data taken from drone and

  18. Dual measurement self-sensing technique of NiTi actuators for use in robust control

    Science.gov (United States)

    Gurley, Austin; Lambert, Tyler Ross; Beale, David; Broughton, Royall

    2017-10-01

    Using a shape memory alloy actuator as both an actuator and a sensor provides huge benefits in cost reduction and miniaturization of robotic devices. Despite much effort, reliable and robust self-sensing (using the actuator as a position sensor) had not been achieved for general temperature, loading, hysteresis path, and fatigue conditions. Prior research has sought to model the intricacies of the electrical resistivity changes within the NiTi material. However, for the models to be solvable, nearly every previous technique only models the actuator within very specific boundary conditions. Here, we measure both the voltage across the entire NiTi wire and of a fixed-length segment of it; these dual measurements allow direct calculation of the actuator length without a material model. We review previous self-sensing literature, illustrate the mechanism design that makes the new technique possible, and use the dual measurement technique to determine the length of a single straight wire actuator under controlled conditions. This robust measurement can be used for feedback control in unknown ambient and loading conditions.

  19. The effect of sensor sheltering and averaging techniques on wind measurements at the Shuttle Landing Facility

    Science.gov (United States)

    Merceret, Francis J.

    1995-01-01

    This document presents results of a field study of the effect of sheltering of wind sensors by nearby foliage on the validity of wind measurements at the Space Shuttle Landing Facility (SLF). Standard measurements are made at one second intervals from 30-feet (9.1-m) towers located 500 feet (152 m) from the SLF centerline. The centerline winds are not exactly the same as those measured by the towers. A companion study, Merceret (1995), quantifies the differences as a function of statistics of the observed winds and distance between the measurements and points of interest. This work examines the effect of nearby foliage on the accuracy of the measurements made by any one sensor, and the effects of averaging on interpretation of the measurements. The field program used logarithmically spaced portable wind towers to measure wind speed and direction over a range of conditions as a function of distance from the obstructing foliage. Appropriate statistics were computed. The results suggest that accurate measurements require foliage be cut back to OFCM standards. Analysis of averaging techniques showed that there is no significant difference between vector and scalar averages. Longer averaging periods reduce measurement error but do not otherwise change the measurement in reasonably steady flow regimes. In rapidly changing conditions, shorter averaging periods may be required to capture trends.

  20. Radiological findings for hip dysplasia at skeletal maturity. Validation of digital and manual measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Engesaeter, Ingvild Oevsteboe [University of Bergen, Department of Surgical Sciences, Bergen (Norway); Haukeland University Hospital, Department of Orthopaedic Surgery, Bergen (Norway); Haukeland University Hospital, Department of Radiology, Bergen (Norway); Haukeland University Hospital, The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Bergen (Norway); Laborie, Lene Bjerke; Rosendahl, Karen [University of Bergen, Department of Surgical Sciences, Bergen (Norway); Haukeland University Hospital, Department of Radiology, Bergen (Norway); Lehmann, Trude Gundersen; Fevang, Jonas; Engesaeter, Lars Birger [University of Bergen, Department of Surgical Sciences, Bergen (Norway); Haukeland University Hospital, Department of Orthopaedic Surgery, Bergen (Norway); Sera, Francesco [University College London Institute of Child Health, Medical Research Council Centre of Epidemiology for Child Health, London (United Kingdom); Pedersen, Douglas; Morcuende, Jose [University of Iowa Hospital and Clinics, Department of Orthopaedics and Rehabilitation, Iowa City, IA (United States); Lie, Stein Atle [Uni Health, Uni Research, Bergen (Norway)

    2012-07-15

    To report on intra-observer, inter-observer, and inter-method reliability and agreement for radiological measurements used in the diagnosis of hip dysplasia at skeletal maturity, as obtained by a manual and a digital measurement technique. Pelvic radiographs from 95 participants (56 females) in a follow-up hip study of 18- to 19-year-old patients were included. Eleven radiological measurements relevant for hip dysplasia (Sharp's, Wiberg's, and Ogata's angles; acetabular roof angle of Toennis; articulo-trochanteric distance; acetabular depth-width ratio; femoral head extrusion index; maximum teardrop width; and the joint space width in three different locations) were validated. Three observers measured the radiographs using both a digital measurement program and manually in AgfaWeb1000. Inter-method and inter- and intra-observer agreement were analyzed using the mean differences between the readings/readers, establishing the 95% limits of agreement. We also calculated the minimum detectable change and the intra-class correlation coefficient. Large variations among different radiological measurements were demonstrated. However, the variation was not related to the use of either the manual or digital measurement technique. For measurements with greater absolute values (Sharp's angle, femoral head extrusion index, and acetabular depth-width ratio) the inter- and intra-observer and inter-method agreements were better as compared to measurements with lower absolute values (acetabular roof angle, teardrop and joint space width). The inter- and intra-observer variation differs notably across different radiological measurements relevant for hip dysplasia at skeletal maturity, a fact that should be taken into account in clinical practice. The agreement between the manual and digital methods is good. (orig.)

  1. Radiological findings for hip dysplasia at skeletal maturity. Validation of digital and manual measurement techniques.

    Science.gov (United States)

    Engesæter, Ingvild Øvstebø; Laborie, Lene Bjerke; Lehmann, Trude Gundersen; Sera, Francesco; Fevang, Jonas; Pedersen, Douglas; Morcuende, José; Lie, Stein Atle; Engesæter, Lars Birger; Rosendahl, Karen

    2012-07-01

    To report on intra-observer, inter-observer, and inter-method reliability and agreement for radiological measurements used in the diagnosis of hip dysplasia at skeletal maturity, as obtained by a manual and a digital measurement technique. Pelvic radiographs from 95 participants (56 females) in a follow-up hip study of 18- to 19-year-old patients were included. Eleven radiological measurements relevant for hip dysplasia (Sharp's, Wiberg's, and Ogata's angles; acetabular roof angle of Tönnis; articulo-trochanteric distance; acetabular depth-width ratio; femoral head extrusion index; maximum teardrop width; and the joint space width in three different locations) were validated. Three observers measured the radiographs using both a digital measurement program and manually in AgfaWeb1000. Inter-method and inter- and intra-observer agreement were analyzed using the mean differences between the readings/readers, establishing the 95% limits of agreement. We also calculated the minimum detectable change and the intra-class correlation coefficient. Large variations among different radiological measurements were demonstrated. However, the variation was not related to the use of either the manual or digital measurement technique. For measurements with greater absolute values (Sharp's angle, femoral head extrusion index, and acetabular depth-width ratio) the inter- and intra-observer and inter-method agreements were better as compared to measurements with lower absolute values (acetabular roof angle, teardrop and joint space width). The inter- and intra-observer variation differs notably across different radiological measurements relevant for hip dysplasia at skeletal maturity, a fact that should be taken into account in clinical practice. The agreement between the manual and digital methods is good.

  2. Wind Turbine Rotor Simulation via CFD Based Actuator Disc Technique Compared to Detailed Measurement

    Directory of Open Access Journals (Sweden)

    Esmail Mahmoodi

    2015-10-01

    Full Text Available In this paper, a generalized Actuator Disc (AD is used to model the wind turbine rotor of the MEXICO experiment, a collaborative European wind turbine project. The AD model as a combination of CFD technique and User Defined Functions codes (UDF, so-called UDF/AD model is used to simulate loads and performance of the rotor in three different wind speed tests. Distributed force on the blade, thrust and power production of the rotor as important designing parameters of wind turbine rotors are focused to model. A developed Blade Element Momentum (BEM theory as a code based numerical technique as well as a full rotor simulation both from the literature are included into the results to compare and discuss. The output of all techniques is compared to detailed measurements for validation, which led us to final conclusions.

  3. Measuring pilot workload in a motion base trainer - A comparison of four techniques

    Science.gov (United States)

    Bortolussi, M. R.; Kantowitz, B. H.; Hart, S. G.

    1985-01-01

    Various techniques have been developed to predict and measure pilot workload. This simulation was conducted in order to compare four widely used methods: A visual two- and four-choice reaction time task, time production, retrospective multi-dimensional subjective ratings and in-flight verbal workload estimates. Two scenarios with different levels of difficulty determined by preliminary research were designed to test these techniques. The insertion of the secondary tasks did not significantly affect flight performance. All four techniques were able to distinguish among levels of scenario complexity. In addition, the three secondary tasks and workload ratings obtained in-flight were generally able to distinguish among levels of difficulty for different segments within the scenarios.

  4. Measuring pilot workload in a motion base trainer. A comparison of four techniques.

    Science.gov (United States)

    Bortolussi, M R; Kantowitz, B H; Hart, S G

    1986-12-01

    Various techniques have been developed to predict and measure pilot workload. This simulation was conducted in order to compare four widely used methods: a visual two-and four-choice reaction time task, time production, retrospective multi-dimensional subjective ratings and in-flight verbal workload estimates. Two scenarios with different levels of difficulty determined by preliminary research were designed to test these techniques. The insertion of the secondary tasks did not significantly affect flight performance. All four techniques were able to distinguish between the overall levels of scenario complexity. In addition, the three secondary tasks and workload ratings obtained in-flight were generally able to distinguish among levels of difficulty for different segments within the scenarios.

  5. Schlieren technique applied to the arc temperature measurement in a high energy density cutting torch

    Science.gov (United States)

    Prevosto, L.; Artana, G.; Mancinelli, B.; Kelly, H.

    2010-01-01

    Plasma temperature and radial density profiles of the plasma species in a high energy density cutting arc have been obtained by using a quantitative schlieren technique. A Z-type two-mirror schlieren system was used in this research. Due to its great sensibility such technique allows measuring plasma composition and temperature from the arc axis to the surrounding medium by processing the gray-level contrast values of digital schlieren images recorded at the observation plane for a given position of a transverse knife located at the exit focal plane of the system. The technique has provided a good visualization of the plasma flow emerging from the nozzle and its interactions with the surrounding medium and the anode. The obtained temperature values are in good agreement with those values previously obtained by the authors on the same torch using Langmuir probes.

  6. Comparison of a novel surface laser scanning anthropometric technique to traditional methods for facial parameter measurements.

    Science.gov (United States)

    Joe, Paula S; Ito, Yasushi; Shih, Alan M; Oestenstad, Riedar K; Lungu, Claudiu T

    2012-01-01

    This study was designed to determine if three-dimensional (3D) laser scanning techniques could be used to collect accurate anthropometric measurements, compared with traditional methods. The use of an alternative 3D method would allow for quick collection of data that could be used to change the parameters used for facepiece design, improving fit and protection for a wider variety of faces. In our study, 10 facial dimensions were collected using both the traditional calipers and tape method and a Konica-Minolta Vivid9i laser scanner. Scans were combined using RapidForm XOR software to create a single complete facial geometry of the subject as a triangulated surface with an associated texture image from which to obtain measurements. A paired t-test was performed on subject means in each measurement by method. Nine subjects were used in this study: five males (one African-American and four Caucasian females) and four females displaying a range of facial dimensions. Five measurements showed significant differences (pLaser scanning measurements showed high precision and accuracy when compared with traditional methods. Significant differences found can be very small changes in measurements and are unlikely to present a practical difference. The laser scanning technique demonstrated reliable and quick anthropometric data collection for use in future projects in redesigning respirators.

  7. Squids, snakes, and polarimeters: A new technique for measuring the magnetic moments of polarized beams

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, P.R.; Luccio, A.U.; Shea, T.J.; Tsoupas, N. [Brookhaven National Laboratory, Upton, New York 11973 (United States of America); Goldberg, D.A. [Lawrence Berkeley Laboratory, Berkeley, California (United States of America)

    1997-01-01

    Effective polarimetry at high energies in hadron and lepton synchrotrons has been a long-standing and difficult problem. In synchrotrons with polarized beams it is possible to cause the direction of the polarization vector of a given bunch to alternate at a frequency which is some subharmonic of the rotation frequency. This can result in the presence of lines in the beam spectrum which are due only to the magnetic moment of the beam and which are well removed from the various lines due to the charge of the beam. The magnitude of these lines can be calculated from first principles. They are many orders of magnitude weaker than the Schottky signals. Measurement of the magnitude of one of these lines would be an absolute measurement of beam polarization. For measuring magnetic field, the Superconducting Quantum Interference Device, or squid, is about five orders of magnitude more sensitive than any other transducer. Using a squid, such a measurement might be accomplished with the proper combination of shielding, pickup loop design, and filtering. The resulting instrument would be fast, non-destructive, and comparatively cheap. In addition, techniques developed in the creation of such an instrument could be used to measure the Schottky spectrum in unprecedented detail. We present specifics of a polarimeter design for the Relativistic Heavy Ion Collider (RHIC) and briefly discuss the possibility of using this technique to measure polarization at high-energy electron machines like LEP and HERA. {copyright} {ital 1997 American Institute of Physics.}

  8. Measuring 3-D location and shape parameters of cylinders by a spatial encoding technique

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.; Chia, T.L.; Ho, S.Y. (National Chiao Tung Univ., Hsinchu (Taiwan, Province of China). Inst. of Computer Science and Information Engineering)

    1994-10-01

    The authors are concerned with the problem of estimation of true cylinder radius, height, location, and orientation. The authors present mathematical models for measuring these location and shape parameters using a spatial encoding technique. A crucial step in the proposed method is to convert the estimation problem with complex curved stripe patterns to an equivalent, but simpler, estimation problem with line stripe patterns. The notions of silhouette edges and virtual plane are introduced. Various projective geometry techniques are applied to derive the cylinder location and shape parameters. The actual experiment apparatus is et up to employ the developed mathematical models to measure the cylinder geometric parameters. Description of the image-processing tasks for extracting perceived curved stripes and stripe endpoints is given. Sensitivity analysis and proper measures are taken to consider the effects of the uncertainties of stripe endpoints and silhouette edge locations on the measurement. Experiments have confirmed that their measurement method yields quite good results for different cylinders under various measurement environment conditions.

  9. Synchrotron X-ray measurement techniques for thermal barrier coated cylindrical samples under thermal gradients

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Sanna F.; Knipe, Kevin; Manero, Albert; Raghavan, Seetha [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Meid, Carla; Wischek, Janine; Bartsch, Marion [German Aerospace Center (DLR), Institute of Materials Research, 51147 Cologne (Germany); Okasinski, John; Almer, Jonathan [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Karlsson, Anette M. [Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio 44115 (United States)

    2013-08-15

    Measurement techniques to obtain accurate in situ synchrotron strain measurements of thermal barrier coating systems (TBCs) applied to hollow cylindrical specimens are presented in this work. The Electron Beam Physical Vapor Deposition coated specimens with internal cooling were designed to achieve realistic temperature gradients over the TBC coated material such as that occurring in the turbine blades of aeroengines. Effects of the circular cross section on the x-ray diffraction (XRD) measurements in the various layers, including the thermally grown oxide, are investigated using high-energy synchrotron x-rays. Multiple approaches for beam penetration including collection, tangential, and normal to the layers, along with variations in collection parameters are compared for their ability to attain high-resolution XRD data from the internal layers. This study displays the ability to monitor in situ, the response of the internal layers within the TBC, while implementing a thermal gradient across the thickness of the coated sample. The thermal setup maintained coating surface temperatures in the range of operating conditions, while monitoring the substrate cooling, for a controlled thermal gradient. Through variation in measurement location and beam parameters, sufficient intensities are obtained from the internal layers which can be used for depth resolved strain measurements. Results are used to establish the various techniques for obtaining XRD measurements through multi-layered coating systems and their outcomes will pave the way towards goals in achieving realistic in situ testing of these coatings.

  10. Synchrotron X-ray measurement techniques for thermal barrier coated cylindrical samples under thermal gradients.

    Science.gov (United States)

    Siddiqui, Sanna F; Knipe, Kevin; Manero, Albert; Meid, Carla; Wischek, Janine; Okasinski, John; Almer, Jonathan; Karlsson, Anette M; Bartsch, Marion; Raghavan, Seetha

    2013-08-01

    Measurement techniques to obtain accurate in situ synchrotron strain measurements of thermal barrier coating systems (TBCs) applied to hollow cylindrical specimens are presented in this work. The Electron Beam Physical Vapor Deposition coated specimens with internal cooling were designed to achieve realistic temperature gradients over the TBC coated material such as that occurring in the turbine blades of aeroengines. Effects of the circular cross section on the x-ray diffraction (XRD) measurements in the various layers, including the thermally grown oxide, are investigated using high-energy synchrotron x-rays. Multiple approaches for beam penetration including collection, tangential, and normal to the layers, along with variations in collection parameters are compared for their ability to attain high-resolution XRD data from the internal layers. This study displays the ability to monitor in situ, the response of the internal layers within the TBC, while implementing a thermal gradient across the thickness of the coated sample. The thermal setup maintained coating surface temperatures in the range of operating conditions, while monitoring the substrate cooling, for a controlled thermal gradient. Through variation in measurement location and beam parameters, sufficient intensities are obtained from the internal layers which can be used for depth resolved strain measurements. Results are used to establish the various techniques for obtaining XRD measurements through multi-layered coating systems and their outcomes will pave the way towards goals in achieving realistic in situ testing of these coatings.

  11. A comparison of ice water content measurement techniques on the FAAM BAe-146 aircraft

    Science.gov (United States)

    Abel, S. J.; Cotton, R. J.; Barrett, P. A.; Vance, A. K.

    2014-09-01

    This paper presents a comparison of ice water content (qi) data from a variety of measurement techniques on the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft. Data are presented from a range of cloud types measured during the PIKNMIX field experiment that include mixed-phase stratocumulus, cumulus congestus and cirrus clouds. These measurements cover a broad range of conditions in which atmospheric ice particles are found in nature, such as the low-ice-water-content environments typically found in midlatitude cirrus and the environments with much higher ice water content often observed in cold convective clouds. The techniques include bulk measurements from (i) a Nevzorov hot-wire probe, (ii) the difference between the measured total water content (condensed plus vapour) and the water vapour content of the atmosphere and (iii) a counterflow virtual impactor (CVI) (only for cirrus measurements). We also estimate the qi from integration of the measured particle size distribution (PSD) with assumptions on how the density of ice particles varies as a function of size. The results show that the only bulk ice water content technique capable of measuring high qi values (several g m-3) was the method of total water content minus water vapour. For low ice water contents we develop a new parametrisation of the Nevzorov baseline drift that enables the probe to be sensitive to qi ± 0.002 g m-3. In cirrus clouds the agreement between the Nevzorov and other bulk measurements was typically better than a factor of 2 for the CVI (qi > 0.008 g m-3) and the method of total water content minus water vapour (qi > 0.02 g m-3). Good agreement with the bulk measurements for all cases could be obtained with the estimate from the PSD provided that appropriate a priori assumptions on the mass-dimension relationship were made. This is problematic in the convective clouds sampled because pristine ice particles, heavily rimed particles and supercooled liquid

  12. A comparison of ice water content measurement techniques on the FAAM BAe-146 aircraft

    Directory of Open Access Journals (Sweden)

    S. J. Abel

    2014-05-01

    Full Text Available This paper presents a comparison of ice water content (qi data from a variety of measurement techniques on the Facility for Airborne Atmospheric Measurements (FAAM BAe-146 research aircraft. Data are presented from a range of cloud types measured during the PIKNMIX field experiment that include mixed phase stratocumulus, cumulus congestus and cirrus clouds. These measurements cover a broad range of conditions in which atmospheric ice particles are found in nature, such as the low ice water content environments typically found in mid-latitude cirrus and the much higher ice water content environments often observed in cold convective clouds. The techniques include bulk measurements from (i a Nevzorov hot-wire probe (ii the difference between the measured total water content (condensed plus vapour and the water vapour content of the atmosphere and (iii a Counterflow Virtual Impactor (CVI (only for cirrus measurements. We also estimate the qi from integration of the measured particle size distribution (PSD with assumptions on how the density of ice particles varies as a function of size. The results show that the only bulk ice water content technique capable of measuring high qi values (several g kg−1 was the total water content minus water vapour method. For low ice water contents we develop a new parametrization of the Nevzorov base-line drift that enables the probe to be sensitive to qi ± 0.002 g m−3. In cirrus clouds the agreement between the Nevzorov and other bulk measurements was typically better than a factor of two for the CVI (qi 0.01 g kg−1 and the total water content minus water vapour method (qi > 0.03 g kg−1. Good agreement with the bulk measurements for all cases could be obtained with the estimate from the PSD provided that appropriate a-priori assumptions on the mass–dimension relationship were made. This is problematic in the convective clouds sampled because pristine ice particles, heavily rimed particles and

  13. A comparison of ice water content measurement techniques on the FAAM BAe-146 aircraft

    Directory of Open Access Journals (Sweden)

    S. J. Abel

    2014-09-01

    Full Text Available This paper presents a comparison of ice water content (qi data from a variety of measurement techniques on the Facility for Airborne Atmospheric Measurements (FAAM BAe-146 research aircraft. Data are presented from a range of cloud types measured during the PIKNMIX field experiment that include mixed-phase stratocumulus, cumulus congestus and cirrus clouds. These measurements cover a broad range of conditions in which atmospheric ice particles are found in nature, such as the low-ice-water-content environments typically found in midlatitude cirrus and the environments with much higher ice water content often observed in cold convective clouds. The techniques include bulk measurements from (i a Nevzorov hot-wire probe, (ii the difference between the measured total water content (condensed plus vapour and the water vapour content of the atmosphere and (iii a counterflow virtual impactor (CVI (only for cirrus measurements. We also estimate the qi from integration of the measured particle size distribution (PSD with assumptions on how the density of ice particles varies as a function of size. The results show that the only bulk ice water content technique capable of measuring high qi values (several g m−3 was the method of total water content minus water vapour. For low ice water contents we develop a new parametrisation of the Nevzorov baseline drift that enables the probe to be sensitive to qi ± 0.002 g m−3. In cirrus clouds the agreement between the Nevzorov and other bulk measurements was typically better than a factor of 2 for the CVI (qi > 0.008 g m−3 and the method of total water content minus water vapour (qi > 0.02 g m−3. Good agreement with the bulk measurements for all cases could be obtained with the estimate from the PSD provided that appropriate a priori assumptions on the mass–dimension relationship were made. This is problematic in the convective clouds sampled because pristine ice particles, heavily rimed particles and

  14. Extending the applicability of the eddy-covariance flux-measurement technique

    Energy Technology Data Exchange (ETDEWEB)

    Nordbo, A.

    2012-07-01

    Surface-atmosphere exchange of momentum, energy and atmospheric constituents affects the atmosphere--from alterations in local microclimates and mesoscale weather to climate modification. These exchange processes can be studied using direct eddy-covariance (EC) measurements of vertical turbulent transport, but the technique has not yet readily been applied in non-prevailing ecosystems. Thus, the aim of this thesis is to extend the applicability of the EC technique in two ways: to non-standard sites and by further developing the technique itself. To reach the aim, EC measurements over a boreal lake and three urban sites in Helsinki were performed. Long-term measurements over a lake revealed that the water below the thermocline was decoupled from the atmosphere and thus not important for atmospheric vertical turbulent fluxes. The energy exchange between the lake and the atmosphere departs from vegetated surfaces especially due to large nocturnal evaporation fuelled by lake-water heat storage. Long-term measurements at a semi-urban site in Helsinki showed that the surface-atmosphere exchange is altered by anthropogenic activity: changes in surface-cover and an additional anthropogenic heat release (13 W m{sup -2}) led to an altered surface energy balance, and anthropogenic CO{sub 2} emissions led to a large positive annual CO{sub 2} balance (1.8 kg C m{sup -2}). Intra-site and intra-city variation in surface-cover led to differences in atmospheric stability and CO{sub 2} emissions. The EC technique evaluation demonstrated that (1) the 'energy imbalance problem' in EC measurements is not primarily surface-cover dependent, and that (2) common calculation errors in EC calculations can be almost 30% of the flux. Water vapour flux measurements with a closed-path analyser were affected by sorption: the signal's arrival is delayed and it is attenuated. A new spectral-correction method based on wavelet analysis was developed to automatically correct for this

  15. Non-invasive techniques for measuring body composition: state of the art and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, S.H.

    1985-01-01

    In the past 20 years, in vivo analysis of body elements by neutron activation has become an important tool in medical research. In particular, it provides a much needed means to make quantitative assessments of body composition of human beings in vivo. The data are useful both for basic physiological understanding and for diagnosis and management of a variety of diseases and disorders. This paper traces the development of the in vivo neutron activation technique from basic systems to the present state of the art facilities. A scan of some of the numerous clinical applications that have been made with this technique, reveals the broad potentialities of in vivo neutron activation. The paper also considers alternative routes of future development and raises some of the questions now faced in making the techniques more widely available to both medical practitioners and medical investigators. In vivo neutron activation has opened a new era of both clinical diagnosis and therapy evaluation, and investigation into the modelling of body composition. The techniques are new, but it is already clear that considerable strides can be made in increasing accuracy and precision, increasing the number of elements susceptible to measurement, and reducing the dose required for the measurement. 18 refs., 7 figs.

  16. Application of Optical Measurement Techniques During Fabrication and Testing of Liquid Rocket Nozzles

    Science.gov (United States)

    Gradl, Paul R.

    2015-01-01

    This paper presents a series of optical measurement techniques that were developed for use during large-scale fabrication and testing of nozzle components. A thorough understanding of hardware throughout the fabrication cycle and hotfire testing is critical to meet component design intent. Regeneratively cooled nozzles and associated tooling require tight control of tolerances during the fabrication process to ensure optimal performance. Additionally, changes in geometry during testing can affect performance of the nozzle and mating components. Structured light scanning and digital image correlation techniques were used to collect data during the fabrication and test of nozzles, in addition to other engine components. This data was used to analyze deformations data during machining, heat treatment, assembly and testing operations. A series of feasibility experiments were conducted for these techniques that led to use on full scale nozzles during the J-2X upper stage engine program in addition to other engine development programs. This paper discusses the methods and results of these measurement techniques throughout the nozzle life cycle and application to other components.

  17. A study of the river velocity measurement techniques and analysis methods

    Science.gov (United States)

    Chung Yang, Han; Lun Chiang, Jie

    2013-04-01

    Velocity measurement technology can be traced back to the pitot tube velocity measurement method in the 18th century and today's velocity measurement technology use the acoustic and radar technology, with the Doppler principle developed technology advances, in order to develop the measurement method is more suitable for the measurement of velocity, the purpose is to get a more accurate measurement data and with the surface velocity theory, the maximum velocity theory and the indicator theory to obtain the mean velocity. As the main research direction of this article is to review the literature of the velocity measurement techniques and analysis methods, and to explore the applicability of the measurement method of the velocity measurement instruments, and then to describe the advantages and disadvantages of the different mean velocity profiles analysis method. Adequate review of the references of this study will be able to provide a reference for follow-up study of the velocity measurement. Review velocity measurement literature that different velocity measurement is required to follow the different flow conditions measured be upgraded its accuracy, because each flow rate measurement method has its advantages and disadvantages. Traditional velocity instrument can be used at low flow and RiverRAD microwave radar or imaging technology measurement method may be applied in high flow. In the tidal river can use the ADCP to quickly measure river vertical velocity distribution. In addition, urban rivers may be used the CW radar to set up on the bridge, and wide rivers can be used RiverRAD microwave radar to measure the velocities. Review the relevant literature also found that using Ultrasonic Doppler Current Profiler with the Chiu's theory to the velocity of observing automation work can save manpower and resources to improve measurement accuracy, reduce the risk of measurement, but the great variability of river characteristics in Taiwan and a lot of drifting floating

  18. A proposed measurement method for void fraction in lubricant oil based on the image processing technique.

    Science.gov (United States)

    Wang, Jianwen; An, Qi

    2008-02-01

    A new method for measuring void fraction in lubricating oils is presented based on the image processing technique. The problem here differs from the bubbles detection problem in two-phase fluids in that our interest lies in the gross amount of gas voids in oils. Our method is based on an observation that gas voids in oils change the color of the mixed gas-oil material. Therefore, a measurement technique was established based on the change in color. In particular, the relationship between the change in color and amount of voids was established experimentally. The experiment and testing were performed on a particular setup which consists of a pipe, oil, and air. The test result has shown that this method is effective. The method is the simplest and most accurate one among the existing methods.

  19. [Methodology and Implementation of Forced Oscillation Technique for Respiratory Mechanics Measurement].

    Science.gov (United States)

    Zhang, Zhengbo; Ni, Lu; Liu, Xiaoli; Li, Deyu; Wang, Weidong

    2015-11-01

    The forced oscillation technique (FOT) is a noninvasive method for respiratory mechanics measurement. For the FOT, external signals (e.g. forced oscillations around 4-40 Hz) are used to drive the respiratory system, and the mechanical characteristic of the respiratory system can be determined with the linear system identification theory. Thus, respiratory mechanical properties and components at different frequency and location of the airway can be explored by specifically developed forcing waveforms. In this paper, the theory, methodology and clinical application of the FOT is reviewed, including measure ment theory, driving signals, models of respiratory system, algorithm for impedance identification, and requirement on apparatus. Finally, the future development of this technique is also discussed.

  20. An accurate automated technique for quasi-optics measurement of the microwave diagnostics for fusion plasma

    Science.gov (United States)

    Hu, Jianqiang; Liu, Ahdi; Zhou, Chu; Zhang, Xiaohui; Wang, Mingyuan; Zhang, Jin; Feng, Xi; Li, Hong; Xie, Jinlin; Liu, Wandong; Yu, Changxuan

    2017-08-01

    A new integrated technique for fast and accurate measurement of the quasi-optics, especially for the microwave/millimeter wave diagnostic systems of fusion plasma, has been developed. Using the LabVIEW-based comprehensive scanning system, we can realize not only automatic but also fast and accurate measurement, which will help to eliminate the effects of temperature drift and standing wave/multi-reflection. With the Matlab-based asymmetric two-dimensional Gaussian fitting method, all the desired parameters of the microwave beam can be obtained. This technique can be used in the design and testing of microwave diagnostic systems such as reflectometers and the electron cyclotron emission imaging diagnostic systems of the Experimental Advanced Superconducting Tokamak.

  1. Protein Structure: Alignment using Mean Field Techniques and Measurement of Isolated Individual Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Blankenbecler, Richard

    2003-03-13

    Techniques originally developed in High Energy Physics have been applied to selected problems in genetics with promising results. First, this talk will briefly review the importance of protein structure from a physics point of view. Then Mean Field Techniques used in detector track fitting algorithms will be applied to the comparison of protein structures. The practical importance of such comparisons will be discussed. Second, the possibility of measuring the charge structure of ''single'' isolated molecules using the proposed SLAC Free Electron Laser will be outlined. This involves the development of an algorithm that determines the orientation of each of the many targeted identical molecules, constructs the 3-D transform from the many 2-D patterns, and finally performs an inverse fourier transform when only the magnitude of the transform is known, since the phase is not measurable.

  2. Outcome Measures of an Intracanal, Endoscopic Transforaminal Decompression Technique: Initial Findings from the MIS Prospective Registry.

    Science.gov (United States)

    Sclafani, Joseph A; Raiszadeh, Kamshad; Laich, Dan; Shen, Jian; Bennett, Matthew; Blok, Robert; Liang, Kevin; Kim, Choll W

    2015-01-01

    Minimally invasive transforaminal endoscopic procedures can achieve spinal decompression through either direct or indirect techniques. Subtle variations in trajectory of the surgical corridor can dictate access to the pathologic tissue. Two general strategies exist: the intradiscal "inside-out" technique and the extradiscal, intracanal (IC) technique. The IC technique utilizes a more lateral transforaminal approach than the intradiscal technique, which allows for a more direct decompression of the spinal canal. This study is an assessment of IC patient outcome data obtained through analysis of a previously validated MIS Prospective Registry. Post-hoc analysis was performed on the MIS Prospective Registry database containing 1032 patients. A subgroup of patients treated with the endoscopic IC technique was identified. Patient outcome measures after treatment of symptomatic disk herniation and neuroforaminal stenosis were evaluated. A total of 86 IC patients were analyzed. Overall, there was significant improvement in employment and walking tolerance as soon as 6 weeks post-op as well as significant one year VAS and ODI score improvement. Subanalysis of IC patients with two distinct primary diagnoses was performed. Group IC-1 (disc herniation) showed improvement in ODI and VAS back and leg outcomes at 1 year post-op. Group IC-2 (foraminal stenosis) showed VAS back and leg score improvement at one year post-op but did not demonstrate significant improvement in overall ODI outcome at any time point. The one year re-operation rate was 2% (1/40) for group IC-1 and 28% (5/18) for group IC-2. The initial results of the MIS Registry IC subgroup show a significant clinical improvement when the technique is employed to treat patients with lumbar disc herniation. The treatment of foraminal stenosis can lead to improved short-term clinical outcome but is associated with a high re-operation rate at 1 year post-op.

  3. Radon exhalation from Libyan soil samples measured with the SSNTD technique.

    Science.gov (United States)

    Saad, A F; Abdallah, R M; Hussein, N A

    2013-02-01

    Radon concentrations in soil samples collected from the cities of Benghazi and Al-Marj, located in northeastern Libya, were measured using the sealed-can technique based on the CR-39 SSNTDs. Mass and areal radon exhalation rates, radium content and radon concentration contribute to indoor radon, and annual effective doses were determined. The results indicate mostly normal rates, but there were some higher levels of radon concentration and emanation in samples collected from Al-Marj and one sample from Benghazi.

  4. Influence of a laser profile in impedance mismatch techniques applied to carbon EOS measurement

    Institute of Scientific and Technical Information of China (English)

    A.Aliverdiev; D.Batani; R.Dezulian

    2013-01-01

    We present a recent numerical analysis of impedance mismatch technique applied to carbon equation of state measurements.We consider high-power laser pulses with a Gaussian temporal profile of different durations.We show that for the laser intensity(≈1014W/cm2)and the target design considered in this paper we need to have laser pulses with rise-time less than 150 ps.

  5. Measurement of anisotropic energy transport in flowing polymers by using a holographic technique

    OpenAIRE

    Schieber, Jay D.; Venerus, David C.; Bush, Kendall; Balasubramanian, Venkat; SMOUKOV, Stoyan

    2004-01-01

    Almost no experimental data exist to test theories for the nonisothermal flow of complex fluids. To provide quantitative tests for newly proposed theories, we have developed a holographic grating technique to study energy transport in an amorphous polymer melt subject to flow. Polyisobutylene with weight-averaged molecular mass of 85 kDa is sheared at a rate of 10 s–1, and all nonzero components of the thermal conductivity tensor are measured as a function of time, after cessation. Our result...

  6. Feasibility of intercostal blood flow measurement by echo-Doppler technique in healthy subjects.

    Science.gov (United States)

    de Bisschop, Claire; Montaudon, Michel; Glénet, Stéphane; Guénard, Hervé

    2017-05-01

    Intercostal artery blood flow supplies the external and internal intercostal muscles, which are inspiratory and expiratory muscles. Intercostal blood flow measured by the echo-Doppler (ED) technique has not previously been reported in humans. This study describes the feasibility of this measurement during free and loaded breathing in healthy subjects. Systolic, diastolic and mean blood flows were measured in the eighth dorsal intercostal space during free and loaded breathing using the ED technique. Flows were calculated as the product of the artery intraluminal surface and blood velocity. Ten healthy subjects (42 ± 13·6 years) were included. Integrated electromyogram (iEMG), arterial pressure, cardiac frequency and breathing pattern were also recorded. Mean blood flows were 3·5 ± 1·2 ml min(-1) at rest, 6 ± 2·6 ml min(-1) while breathing through a combined inspiratory and expiratory resistance and 4·0 ± 1·3 ml min(-1) 1 min after unloading. Diastolic blood flow was about one-third the systolic blood flow. The changes in blood flows were consistent with those in iEMG. No change in mean blood flow was observed between inspiration and expiration, suggesting a balance in the perfusion of external and internal muscles during breathing. In conclusion, ED is a feasible technique for non-invasive, real-time measurement of intercostal blood flow in humans. In healthy subjects, mean blood flow appeared tightly matched to iEMG activity. This technique may provide a way to assess the vascular adaptations induced by diseases in which respiratory work is increased or cardiac blood flow altered. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  7. A technique for measuring velocity and attenuation of ultrasound in liquid foams

    CERN Document Server

    Pierre, Juliette; Leroy, Valentin

    2012-01-01

    We describe an experimental setup specifically designed for measuring the ultrasonic transmission through liquid foams, over a broad range of frequencies (60-600 kHz). The question of determining the ultrasonic properties of the foam (density, phase velocity and attenuation) from the transmission measurements is addressed. An inversion method is proposed, tested on synthetic data, and applied to a liquid foam at different times during the coarsening. The ultrasonic velocity and attenuation are found to be very sensitive to the foam bubble sizes, suggesting that a spectroscopy technique could be developed for liquid foams.

  8. Measuring fusion excitation functions with RIBs using the stacked target technique: Problems and possible solutions

    Directory of Open Access Journals (Sweden)

    Fisichella M.

    2016-01-01

    Full Text Available For measuring fusion excitation functions, the activation technique with a stack of targets offers the considerable advantage that several reaction energies may be simultaneously measured by using one beam energy. However, its main drawback is the degradation of the beam quality as it passes through the stack due to statistical nature of energy loss processes and any non-uniformity of the stacked targets. If not taken properly into account, this degradation can lead to a wrong determination of the fusion excitation function. In this contribution some results of the investigation of this problem are reported.

  9. Techniques and Apparatus for Measuring Rotational Core Losses of Soft Magnetic Materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.

  10. Application of the Zisman Critical Surface Tension Technique to Textile Materials Using Contact Angle Measurements

    Institute of Scientific and Technical Information of China (English)

    江红; 迟克栋; 吴慧莉

    2001-01-01

    This is the first one that applies the Zisman critical surface tension technique successfully to textile materials. It was accomplished by carefully determination of the contact angle of fabric. The deviation caused by the porous structure of the fabric will be taken into account. To do so, a Jens equation is applied, and the measured contact angles can be corrected. The surface porosity was determined by measurement and approximate calculation, and the chemical composition of the surface was characterized by means of attenuated total reflection Fourier-transform infrared(FTIR/ATR).

  11. Application of thermal lens technique to measure the thermal diffusivity of biodiesel blend

    Science.gov (United States)

    Sadrolhosseini, Amir Reza; Noor, A. S. M.; Mehdipour, Lotf Ali; Noura, Amin; Mahdi, Mohd Adzir

    2015-04-01

    Thermal diffusivity of palm biodiesel blends was measured using a thermal lens double beam setup. Palm biodiesel blends were prepared from a mixture of normal palm oil biodiesel and diesel fuel with the percentage of the mixture set in the range of 10-90 %. The thermal diffusivity of the palm biodiesel blends consistently increased by increasing the concentration of palm biodiesel from 0.784 × 10-7 to 1.056 × 10-7 m2/s and average of measurement limitation was 0.629 × 10-7 m2/s. Hence, thermal lens technique is suitable and accurate to assess the thermal diffusivity of palm biodiesel.

  12. Automatized channel for resistivity measurements in layered materials by four-point probe technique

    Science.gov (United States)

    Gryaznov, A. O.; Savchenko, S. S.; Vokhmintsev, A. S.; Weinstein, I. A.

    2016-09-01

    An automatized channel for measuring the resistivity in materials by the four-point probe technique was developed. The installation was based on Cascade Microtech MPS150 microprobe station, National Instruments PXIe-4143 power supply unit and PXI-4072 digital multimeter. Registration modes of surface and bulk specific resistance for samples with positioning the probes in a line or at square vertices were implemented. Measurements under corresponding modes were carried out for metallic, semiconducting bulk samples and thin coatings. Conductive and optical properties of 10, 20 and 30 nm Au layers formed on quartz glass by magnetron sputtering were investigated.

  13. Scale-model charge-transfer technique for measuring enhancement factors

    Science.gov (United States)

    Kositsky, J.; Nanevicz, J. E.

    1991-01-01

    Determination of aircraft electric field enhancement factors is crucial when using airborne field mill (ABFM) systems to accurately measure electric fields aloft. SRI used the scale model charge transfer technique to determine enhancement factors of several canonical shapes and a scale model Learjet 36A. The measured values for the canonical shapes agreed with known analytic solutions within about 6 percent. The laboratory determined enhancement factors for the aircraft were compared with those derived from in-flight data gathered by a Learjet 36A outfitted with eight field mills. The values agreed to within experimental error (approx. 15 percent).

  14. Thermal diffusivity measurements in the photoacoustic open-cell configuration using simple signal normalization techniques

    Science.gov (United States)

    Balderas-López, J. A.; Mandelis, A.

    2001-09-01

    A generalized model for the open photoacoustic cell configuration (OPC) technique, involving one-dimensional heat diffusion across two layers, is presented. The analytical results are particularly suitable for applications with dielectric solids, such as polymers and resins. Two effective normalization procedures for simple and reliable measurement of the thermal diffusivity of this kind of materials using an OPC are also presented. The thermal diffusivity of three different materials (a dental resin, an epoxy resin, and a polymer foil) was measured and excellent agreement was obtained with some values reported in the literature. 2001 American Institute of Physics.

  15. High sensitivity probe absorption technique for time-of-flight measurements on cold atoms

    Indian Academy of Sciences (India)

    A K Mohapatra; C S Unnikrishnan

    2006-06-01

    We report on a phase-sensitive probe absorption technique with high sensitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms. We demonstrate the high sensitivity and figure of merit of the simple method by measuring the time-of-flight of atoms moving upwards from a magneto-optical trap released in the gravitational field.

  16. Elastic modulus measurements of LDEF glasses and glass-ceramics using a speckle technique

    Science.gov (United States)

    Wiedlocher, D. E.; Kinser, D. L.

    1992-01-01

    Elastic moduli of five glass types and the glass-ceramic Zerodur, exposed to a near-earth orbit environment on the Long Duration Exposure Facility (LDEF), were compared to that of unexposed samples. A double exposure speckle photography technique utilizing 633 nm laser light was used in the production of the speckle pattern. Subsequent illumination of a double exposed negative using the same wavelength radiation produces Young's fringes from which the in-plane displacements are measured. Stresses imposed by compressive loading produced measurable strains in the glasses and glass-ceramic.

  17. New lifetime measurements in the stable semimagic Sn isotopes using the Doppler-shift attenuation technique

    Science.gov (United States)

    Jungclaus, A.; Walker, J.; Leske, J.; Speidel, K.-H.; Stuchbery, A. E.; East, M.; Boutachkov, P.; Cederkäll, J.; Doornenbal, P.; Egido, J. L.; Ekström, A.; Gerl, J.; Gernhäuser, R.; Goel, N.; Górska, M.; Kojouharov, I.; Maier-Komor, P.; Modamio, V.; Naqvi, F.; Pietralla, N.; Pietri, S.; Prokopowicz, W.; Schaffner, H.; Schwengner, R.; Wollersheim, H.-J.

    2011-09-01

    Precise measurements of lifetimes in the picosecond range of excited states in the stable even-A Sn isotopes 112,114,116,122Sn have been performed using the Doppler shift attenuation technique. For the first excited 2+ states in 112Sn, 114Sn and 116Sn the E2 transition strengths deduced from the measured lifetimes are in disagreement with the previously adopted values. They indicate a shallow minimum at N = 66 in contrast to the maximum at mid-shell predicted by modern shell model calculations.

  18. A measurement technique to identify and locate partial discharge in transformer with AE and HFCT

    Directory of Open Access Journals (Sweden)

    Urairat Fuangsoongnern

    2014-02-01

    Full Text Available This paper proposes a measurement technique to identify and locate the occurrence of partial discharge (PD in the insulation of oil immersed and dry type distribution transformers. With reference to IEEE Std. C57.127- 2007, four acoustic transducers type PD-TP500A were used to locate PD and one HFCT (High frequency current transducer was used to identify PD. This process could accurately identify and locate the source of PD occurring at any position in a distribution transformer. The result of the findings enabled us to prevent damage and deploy defensive maintenance measure on the distribution transformer in time.

  19. Technique of torsion measurement of the lower extremity using computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Widjaja, P.M.; Ermers, J.W.; Sijbrandij, S.; Damsma, H.; Klinkhamer, A.C.

    1985-05-01

    Axial CT is the most accurate and convenient technique for the measurement of lower limb torsion; its accuracy is equal to that of cadaveric skeletal measurement. Both extremities are examined simultaneously, and the comparison of the right and the left leg provides the most important value. The torsion angulation is obtained directly by superimposing the magnified image of each scan on the other. Patient positioning is comfortable and a relatively short examination time is required. It does not require special equipment or skill on the part of the examiner. The radiation dose appears to be lower than that of the conventional radiographic method.

  20. A Noncontact Measurement Technique for the Density and Thermal Expansion Coefficient of Solid and Liquid Materials

    Science.gov (United States)

    Chung, Sang K.; Thiessen, David B.; Rhim, Won-Kyu

    1996-01-01

    A noncontact measurement technique for the density and the thermal expansion refractory materials in their molten as well as solid phases is presented. This technique is based on the video image processing of a levitated sample. Experiments were performed using the high-temperature electrostatic levitator (HTESL) at the Jet Propulsion Laboratory in which 2-3 mm diameter samples can be levitated, melted, and radiatively cooled in a vacuum. Due to the axisymmetric nature of the molten samples when levitated in the HTESL, a rather simple digital image analysis can be employed to accurately measure the volumetric change as a function of temperature. Density and the thermal expansion coefficient measurements were made on a pure nickel sample to test the accuracy of the technique in the temperature range of 1045-1565 C. The result for the liquid phase density can be expressed by p = 8.848 + (6.730 x 10(exp -4)) x T (degC) g/cu cm within 0.8% accuracy, and the corresponding thermal expansion coefficient can be expressed by Beta=(9.419 x 10(exp -5)) - (7.165 x 10(exp -9) x T (degC)/K within 0.2% accuracy.