New analytical portable instrument for microchip electrophoresis with electrochemical detection.

Science.gov (United States)

Fernández-la-Villa, Ana; Pozo-Ayuso, Diego F; Castaño-Alvarez, Mario

2010-08-01

A new portable instrument that includes a high voltage power supply, a bipotentiostat, and a chip holder has been especially developed for using microchips electrophoresis with electrochemical detection. The main unit of the instrument has dimensions of 150 x 165 x 70 mm (wxdxh) and consists of a four-outputs high voltage power supply with a maximum voltage of +/-3 KV and an acquisition system with two channels for dual amperometric (DC or pulsed amperometric detection) detection. Electrochemical detection has been selected as signal transduction method because it is relatively easily implemented, since nonoptical elements are required. The system uses a lithium-ion polymer battery and it is controlled from a desktop or laptop PC with a graphical user interface based on LabVIEW connected by serial RS232 or Bluetooth. The last part of the system consists of a reusable chip holder for housing the microchips, which contain all the electrical connections and reservoirs for making the work with microchips easy. The performance of the new instrument has been evaluated and compared with other commercially available apparatus using single- and dual-channel pyrex microchips for the separation of the neurotransmitters dopamine, epinephrine, and 3,4-dihydroxy-L-phenyl-alanine. The reduction of the size of the instrument has not affected the good performance of the separation and detection using microchips electrophoresis with electrochemical detection. Moreover, the new portable instrument paves the way for in situ analysis making the use of microchips electrophoresis easier.

Material limitations on the detection limit in refractometry

DEFF Research Database (Denmark)

Skafte-Pedersen, Peder; Nunes, Pedro; Xiao, Sanshui

2009-01-01

We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and...

A labview approach to instrumentation for the TFTR bumper limiter alignment project

International Nuclear Information System (INIS)

Skelly, G.N.; Owens, D.K.

1992-01-01

This paper reports on a project recently undertaken to measure the alignment of the TFTR bumper limiter in relation to the toroidal magnetic field axis. The process involved the measurement of the toroidal magnetic field, and the positions of the tiles that make up the bumper limiter. The basis for the instrument control and data acquisition system was National Instrument's LabVIEW 2. LabVIEW is a graphical programming system for developing scientific and engineering applications on a Macintosh. For this project, a Macintosh IIci controlled the IEEE-488 GPIB programmable instruments via an interface box connected to the SCSI port of the computer. With LabVIEW, users create graphical software modules called virtual instruments instead of writing conventional text-based code. To measure the magnetic field, the control system acquired data from two nuclear magnetic resonance magnetometers while the torroidal field coils were pulsed. To measure the position of the tiles on the limiter, an instrumented mechanical arm was used inside the vessel

Computer-based instrumentation for partial discharge detection in GIS

International Nuclear Information System (INIS)

Md Enamul Haque; Ahmad Darus; Yaacob, M.M.; Halil Hussain; Feroz Ahmed

2000-01-01

Partial discharge is one of the prominent indicators of defects and insulation degradation in a Gas Insulated Switchgear (GIS). Partial discharges (PD) have a harmful effect on the life of insulation of high voltage equipment. The PD detection using acoustic technique and subsequent analysis is currently an efficient method of performing non-destructive testing of GIS apparatus. A low cost PC-based acoustic PD detection instrument has been developed for the non-destructive diagnosis of GIS. This paper describes the development of a PC-based instrumentation system for partial discharge detection in GIS and some experimental results have also presented. (Author)

Designing Successful Next-Generation Instruments to Detect the Epoch of Reionization

Science.gov (United States)

Thyagarajan, Nithyanandan; Hydrogen Epoch of Reionization Array (HERA) team, Murchison Widefield Array (MWA) team

2018-01-01

The Epoch of Reionization (EoR) signifies a period of intense evolution of the Inter-Galactic Medium (IGM) in the early Universe caused by the first generations of stars and galaxies, wherein they turned the neutral IGM to be completely ionized by redshift ≥ 6. This important epoch is poorly explored to date. Measurement of redshifted 21 cm line from neutral Hydrogen during the EoR is promising to provide the most direct constraints of this epoch. Ongoing experiments to detect redshifted 21 cm power spectrum during reionization, including the Murchison Widefield Array (MWA), Precision Array for Probing the Epoch of Reionization (PAPER), and the Low Frequency Array (LOFAR), appear to be severely affected by bright foregrounds and unaccounted instrumental systematics. For example, the spectral structure introduced by wide-field effects, aperture shapes and angular power patterns of the antennas, electrical and geometrical reflections in the antennas and electrical paths, and antenna position errors can be major limiting factors. These mimic the 21 cm signal and severely degrade the instrument performance. It is imperative for the next-generation of experiments to eliminate these systematics at their source via robust instrument design. I will discuss a generic framework to set cosmologically motivated antenna performance specifications and design strategies using the Precision Radio Interferometry Simulator (PRISim) -- a high-precision tool that I have developed for simulations of foregrounds and the instrument transfer function intended primarily for 21 cm EoR studies, but also broadly applicable to interferometer-based intensity mapping experiments. The Hydrogen Epoch of Reionization Array (HERA), designed in-part based on this framework, is expected to detect the 21 cm signal with high significance. I will present this framework and the simulations, and their potential for designing upcoming radio instruments such as HERA and the Square Kilometre Array (SKA).

Effects of Kapton Sample Cell Windows on the Detection Limit of Smectite: Implications for CheMin on the Mars Science Laboratory Mission

Science.gov (United States)

Achilles, C. N.; Ming, Douglas W.; Morris, R. V.; Blake, D. F.

2012-01-01

The CheMin instrument on the Mars Science Laboratory (MSL) rover Curiosity is an X-ray diffraction (XRD) and X-ray fluorescence (XRF) instrument capable of providing the mineralogical and chemical compositions of rocks and soils on the surface of Mars. CheMin uses a microfocus X-ray tube with a Co target, transmission geometry, and an energy-discriminating X-ray sensitive CCD to produce simultaneous 2-D XRD patterns and energy-dispersive X-ray histograms from powdered samples. CheMin has two different window materials used for sample cells -- Mylar and Kapton. Instrument details are provided elsewhere. Fe/Mg-smectite (e.g., nontronite) has been identified in Gale Crater, the MSL future landing site, by CRISM spectra. While large quantities of phyllosilicate minerals will be easily detected by CheMin, it is important to establish detection limits of such phases to understand capabilities and limitations of the instrument. A previous study indicated that the (001) peak of smectite at 15 Ang was detectable in a mixture of 1 wt.% smectite with olivine when Mylar is the window material for the sample cell. Complications arise when Kapton is the window material because Kapton itself also has a diffraction peak near 15 Ang (6.8 deg 2 Theta). This study presents results of mineral mixtures of smectite and olivine to determine smectite detection limits for Kapton sample cells. Because the intensity and position of the smectite (001) peak depends on the hydration state, we also analyzed mixtures with "hydrated" and "dehydrated"h smectite to examine the effects of hydration state on detection limits.

Performance acceptance test of a portable instrument to detect uranium in water at the DOE Advanced Waste Water Treatment Plant, Fernald, Ohio

International Nuclear Information System (INIS)

Anderson, M.S.; Weeks, S.J.

1997-01-01

The Eppendorf-Biotronik Model IC 2001-2, a portable field ruggedized ion chromatography instrument, was rigorously tested at the DOE Advanced Waste Water Treatment Plant, Fernald, Ohio. This instrument rapidly detected the uranium concentration in water, and has a detection limit in the low ppb range without using the sample concentrating feature. The test set of samples analyzed included: ''Real World'' water samples from the AWWT containing uranium concentrations in the 9--110 ppb range, a sample blank, and a performance evaluation sample. The AWWT samples contained sets of both raw water and acid-preserved water samples. Selected samples were analyzed in quadruplicate to asses the instrument's precision, and these results were compared with the results from an off-site confirmatory laboratory to assess the instrument's accuracy. Additional comparisons with on-site laboratory instruments, Chemcheck KPA-11 and Scintrex UA-3 are reported. Overall, the Eppendorf-Biotronik IC 2001-2 performed exceptionally well providing a detection limit in the low ppb region (< 10 ppb) and giving rapid (< 5 minutes) accurate and reproducible analytical results for the AWWT, ''real world'', water samples with uranium concentrations in the region of interest (10--40 ppb). The per sample operating cost for this instrument is equivalent to the per sample cost for the currently used KPA. The time required to analyze a sample and provide a result is approximately the same for the CI 2001-2, KPA, and Scintrex instruments

Development of an instrument for direct ozone production rate measurements: measurement reliability and current limitations

Science.gov (United States)

Sklaveniti, Sofia; Locoge, Nadine; Stevens, Philip S.; Wood, Ezra; Kundu, Shuvashish; Dusanter, Sébastien

2018-02-01

Ground-level ozone (O3) is an important pollutant that affects both global climate change and regional air quality, with the latter linked to detrimental effects on both human health and ecosystems. Ozone is not directly emitted in the atmosphere but is formed from chemical reactions involving volatile organic compounds (VOCs), nitrogen oxides (NOx = NO + NO2) and sunlight. The photochemical nature of ozone makes the implementation of reduction strategies challenging and a good understanding of its formation chemistry is fundamental in order to develop efficient strategies of ozone reduction from mitigation measures of primary VOCs and NOx emissions. An instrument for direct measurements of ozone production rates (OPRs) was developed and deployed in the field as part of the IRRONIC (Indiana Radical, Reactivity and Ozone Production Intercomparison) field campaign. The OPR instrument is based on the principle of the previously published MOPS instrument (Measurement of Ozone Production Sensor) but using a different sampling design made of quartz flow tubes and a different Ox (O3 and NO2) conversion-detection scheme composed of an O3-to-NO2 conversion unit and a cavity attenuated phase shift spectroscopy (CAPS) NO2 monitor. Tests performed in the laboratory and in the field, together with model simulations of the radical chemistry occurring inside the flow tubes, were used to assess (i) the reliability of the measurement principle and (ii) potential biases associated with OPR measurements. This publication reports the first field measurements made using this instrument to illustrate its performance. The results showed that a photo-enhanced loss of ozone inside the sampling flow tubes disturbs the measurements. This issue needs to be solved to be able to perform accurate ambient measurements of ozone production rates with the instrument described in this study. However, an attempt was made to investigate the OPR sensitivity to NOx by adding NO inside the instrument

Instrument for the detection of meteors in the infrared

Science.gov (United States)

Svedhem, H.; Koschny, D.; Ter Haar, J.

2014-07-01

The flux of interplanetary particles in the size range 2 mm to 20 m is poorly constrained due to insufficient data --- the larger bodies may be observed remotely by ground-based or space-based telescopes and the smaller particles are measured by in-situ impact detectors in space or by meteor cameras from ground. An infrared video rate imager in Earth orbit would enable a systematic characterization for an extended period, day and night, of the flux in this range by monitoring the bright meteor/fireball generated during atmospheric entry. Due to the low flux of meteoroids in this range a very large detector is required. With this method a large portion of the Earth atmosphere is in fact used as a huge detector. Such an instrument has never flown in Earth orbit. The only sensors of a similar kind fly on US defense satellites for monitoring launches of ballistic missiles. The data from these sensors, however, is largely inaccessible to scientists. The knowledge on emission of light by meteors/bolides at infrared wavelengths is very limited while it can be suspected that the continuum emission from meteors/bolides have stronger emission at infrared wavelengths than in the visible due to the likely low temperatures of these events. At the same time line emission is dominating over the continuum in the visible so it is not clear how this will compare with the continuum in the infrared. We have developed a bread-board version of an IR video rate camera, the SPOSH-IR. The instrument is based on an earlier technology development, SPOSH --- Smart Panoramic Optical Sensor Head, for operation in the visible range, but with the sensor replaced by a cooled IR detector and new infrared optics. The earlier work has proven the concept of the instrument and of automatic detection of meteors/bolides in the visible wavelength range. The new hardware has been built by Jena-Optronik, Jena, Germany and has been tested during several meteor showers in the Netherlands and at ESA's OGS

Limits of detection and decision. Part 4

International Nuclear Information System (INIS)

Voigtman, E.

2008-01-01

Probability density functions (PDFs) have been derived for a number of commonly used limit of detection definitions, including several variants of the Relative Standard Deviation of the Background-Background Equivalent Concentration (RSDB-BEC) method, for a simple linear chemical measurement system (CMS) having homoscedastic, Gaussian measurement noise and using ordinary least squares (OLS) processing. All of these detection limit definitions serve as both decision and detection limits, thereby implicitly resulting in 50% rates of Type 2 errors. It has been demonstrated that these are closely related to Currie decision limits, if the coverage factor, k, is properly defined, and that all of the PDFs are scaled reciprocals of noncentral t variates. All of the detection limits have well-defined upper and lower limits, thereby resulting in finite moments and confidence limits, and the problem of estimating the noncentrality parameter has been addressed. As in Parts 1-3, extensive Monte Carlo simulations were performed and all the simulation results were found to be in excellent agreement with the derived theoretical expressions. Specific recommendations for harmonization of detection limit methodology have also been made

A leak-detection instrument for long buried pipelines based on radioactive tracer measurements

International Nuclear Information System (INIS)

Lu Qingqian; Zhou Shuxuan; Tang Yonghua; Sun Xiaolei; Hu Xusheng; Li Deyi; Yin Liqiang

1987-01-01

The instrument introduced provides a means for leak detection of long buried pipelines based on the radioactive tracer technique. The principle, block diagram and performances for the instrument are described. The leak-detecting method and the determination of some related parameters are also presented. Leak-detection sensitivity of the instrument is 185 kBq (5 μCi). Accuracy for leak localization is within 2.5 m (per km). It is suitable for the buried light oil (gasoline, kerosene, diesel oil) and industrial water pipelines with a diameter of 15 or 20 cm. The detection length for a single operation reaches up to 50 km

Gadolinium for neutron detection in current nuclear instrumentation research: A review

Science.gov (United States)

Dumazert, J.; Coulon, R.; Lecomte, Q.; Bertrand, G. H. V.; Hamel, M.

2018-02-01

Natural gadolinium displays a number of remarkable physical properties: it is a rare earth element, composed of seven stable or quasi-stable isotopes, with an exceptionally high magnetization and a Curie point near room temperature. Its use in the field of nuclear instrumentation historically relates to its efficiency as a neutron poison in power reactors. Gadolinium is indeed the naturally occurring element with the highest interaction probability with neutrons at thermal energy, shared between Gd-157 (15.65%, 254000 b cross section) and Gd-155 (14.8%, 60900 b) isotopes. Considering that neutron capture results in an isotopic change, followed by a radiative rearrangement of nuclear and atomic structures, Gd may be embodied not merely as a neutron poison but as a neutron converter into a prompt photon and an electron source term. Depending on the nature and energy of the reaction products (from a few-keV Auger electrons up to 8 MeV gamma rays) that the detector aims at isolating as an indirect neutron signature, a variety of sensor media and counting methods have been introduced during the last decades. This review first draws a theoretical description of the radiative cascade following Gd(n , γ) capture. The cascade may be subdivided into regions of interest, each corresponding to dedicated detection designs and optimizations whose current status is detailed. This inventory has allowed the authors to extract and benchmark key figures of merit for the definition of a detection scheme: neutron attenuation, neutron sensitivity (cps/nv), gamma rejection, neutron detection limit in a mixed field, intrinsic or extrinsic moderation, and transportability. On this basis, the authors have identified promising paths for Gd-based neutron detection in contemporary instrumentation.

Portable instrument for selectively detecting alpha-particles derived from radon

International Nuclear Information System (INIS)

Chapuis, A.M.; DaJlevic, D.

1975-01-01

A portable instrument of the pocket type designed primarily for monitoring atmospheric contamination in uranium mines by selectively detecting the α-particles emitted simultaneously by the daughter products of radon, namely radium A and radium C' is described. The instrument comprises in combination a tube containing a suction fan for drawing external air through a filter which retains the α-emitting aerosols, a detector in which the α-particles corresponding to the respective energies of the α-emissions of radium A and of radium C' are detected separately, and two collimators placed between the filter and the detector

Diagnostic instrumentation for detection of the onset of steam tube leaks in PWRs

International Nuclear Information System (INIS)

Roach, W.H.

1984-01-01

Four tasks are addressed in this study of the detection of steam tube leaks: determination of which physical parameters indicate the onset of steam generator tube leaks; establishing performance goals for diagnostic instruments which could be used for early detection of steam generator tube leaks; defining the diagnostic instrumentation and their location which satisfy Items 1 and 2; and assessing the need for diagnostic data processing and display. Parameters are identified, performance goals established and sensor types and locations are specified in the report, with emphasis on the use of existing instrumentation with a minimum of retrofitting. A simple algorithm is developed which yields the leak rate as a function of known or measurable quantities. The conclusion is that leak rates of less than one-tenth gram per second should be detectable with existing instrumentation

Highly sensitive rapid fluorescence detection of protein residues on surgical instruments

International Nuclear Information System (INIS)

Kovalev, Valeri I; Bartona, James S; Richardson, Patricia R; Jones, Anita C

2006-01-01

There is a risk of contamination of surgical instruments by infectious protein residues, in particular, prions which are the agents for Creutzfeldt-Jakob Disease in humans. They are exceptionally resistant to conventional sterilization, therefore it is important to detect their presence as contaminants so that alternative cleaning procedures can be applied. We describe the development of an optimized detection system for fluorescently labelled protein, suitable for in-hospital use. We show that under optimum conditions the technique can detect ∼10 attomole/cm 2 with a scan speed of ∼3-10 cm 2 /s of the test instrument's surface. A theoretical analysis and experimental measurements will be discussed

Detection of random alterations to time-varying musical instrument spectra.

Science.gov (United States)

Horner, Andrew; Beauchamp, James; So, Richard

2004-09-01

The time-varying spectra of eight musical instrument sounds were randomly altered by a time-invariant process to determine how detection of spectral alteration varies with degree of alteration, instrument, musical experience, and spectral variation. Sounds were resynthesized with centroids equalized to the original sounds, with frequencies harmonically flattened, and with average spectral error levels of 8%, 16%, 24%, 32%, and 48%. Listeners were asked to discriminate the randomly altered sounds from reference sounds resynthesized from the original data. For all eight instruments, discrimination was very good for the 32% and 48% error levels, moderate for the 16% and 24% error levels, and poor for the 8% error levels. When the error levels were 16%, 24%, and 32%, the scores of musically experienced listeners were found to be significantly better than the scores of listeners with no musical experience. Also, in this same error level range, discrimination was significantly affected by the instrument tested. For error levels of 16% and 24%, discrimination scores were significantly, but negatively correlated with measures of spectral incoherence and normalized centroid deviation on unaltered instrument spectra, suggesting that the presence of dynamic spectral variations tends to increase the difficulty of detecting spectral alterations. Correlation between discrimination and a measure of spectral irregularity was comparatively low.

IAEA eLearning Program: The Use of Radiation Detection Instruments

International Nuclear Information System (INIS)

2010-01-01

This CD-ROM contains a computer based training on Radiation Detection Techniques for Nuclear Security Applications. The IAEA Nuclear Security eLearning tool offers computer based training to Frontline Officers to improve their understanding about key elements of the use of radiation detection instruments. The eLearning program prepares Frontline Officers for the IAEA Detection and Response Frontline Officer course

Soil monitoring instrumentation

International Nuclear Information System (INIS)

Umbarger, C.J.

1981-01-01

The Los Alamos Scientific Laboratory (LASL) has an extensive program for the development of nondestructive assay instrumentation for the quantitative analysis of transuranic (TRU) materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. Included are wastes generated in decontamination and decommissioning of outdated nuclear facilities, as well as from old waste-burial-ground exhumation programs. The assay instrumentation is designed to have detection limits below 10 nCi/g wherever practicable. The assay instrumentation that is applied specifically to soil monitoring is discussed

Highly sensitive rapid fluorescence detection of protein residues on surgical instruments

Energy Technology Data Exchange (ETDEWEB)

Kovalev, Valeri I [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Bartona, James S [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Richardson, Patricia R [School of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ (United Kingdom); Jones, Anita C [School of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ (United Kingdom)

2006-07-15

There is a risk of contamination of surgical instruments by infectious protein residues, in particular, prions which are the agents for Creutzfeldt-Jakob Disease in humans. They are exceptionally resistant to conventional sterilization, therefore it is important to detect their presence as contaminants so that alternative cleaning procedures can be applied. We describe the development of an optimized detection system for fluorescently labelled protein, suitable for in-hospital use. We show that under optimum conditions the technique can detect {approx}10 attomole/cm{sup 2} with a scan speed of {approx}3-10 cm{sup 2}/s of the test instrument's surface. A theoretical analysis and experimental measurements will be discussed.

An instrument for real time detection of contamination in space environmental tests chambers

Science.gov (United States)

Richmond, R. G.; Harmon, H. N.

1972-01-01

An instrument for in situ vacuum detection of surface reflectance changes at 1216A was designed. Using successive reflections, this instrument is more sensitive as an indicator of reflectance changes than similar instruments having only a single reflection. The selection of each component of the instrument and its operational performance is discussed.

FJ-2207 measuring instrument detection pipe surface a level of pollution method

International Nuclear Information System (INIS)

Wang Jiangong

2010-01-01

On the pipe surface contamination were detected α level of pollution is a frequently encountered dose-detection work. Because the pipeline surface arc, while the measuring probe for the plane, which for accurate measurement difficult. In this paper, on the FJ-2207-type pipe surface contamination measuring instrument measuring pollution levels in the α method was studied. Introduced the FJ-2207 measuring instrument detection pipe surface α pollution levels. Studied this measuring instrument on the same sources of surface, plane α level of radioactivity measured differences in the results obtained control of the apparatus when the direct measurement of the surface correction factor, and gives 32-216 specifications commonly used pipe direct measurement of the amendment factor. Convenient method, test results are reliable for the accurate measurement of pipe pollution levels in the surface of α as a reference and learning. (authors)

Intercomparison of NO3 radical detection instruments in the atmosphere simulation chamber SAPHIR

Directory of Open Access Journals (Sweden)

H.-P. Dorn

2013-05-01

Full Text Available The detection of atmospheric NO3 radicals is still challenging owing to its low mixing ratios (≈ 1 to 300 pptv in the troposphere. While long-path differential optical absorption spectroscopy (DOAS has been a well-established NO3 detection approach for over 25 yr, newly sensitive techniques have been developed in the past decade. This publication outlines the results of the first comprehensive intercomparison of seven instruments developed for the spectroscopic detection of tropospheric NO3. Four instruments were based on cavity ring-down spectroscopy (CRDS, two utilised open-path cavity-enhanced absorption spectroscopy (CEAS, and one applied "classical" long-path DOAS. The intercomparison campaign "NO3Comp" was held at the atmosphere simulation chamber SAPHIR in Jülich (Germany in June 2007. Twelve experiments were performed in the well-mixed chamber for variable concentrations of NO3, N2O5, NO2, hydrocarbons, and water vapour, in the absence and in the presence of inorganic or organic aerosol. The overall precision of the cavity instruments varied between 0.5 and 5 pptv for integration times of 1 s to 5 min; that of the DOAS instrument was 9 pptv for an acquisition time of 1 min. The NO3 data of all instruments correlated excellently with the NOAA-CRDS instrument, which was selected as the common reference because of its superb sensitivity, high time resolution, and most comprehensive data coverage. The median of the coefficient of determination (r2 over all experiments of the campaign (60 correlations is r2 = 0.981 (quartile 1 (Q1: 0.949; quartile 3 (Q3: 0.994; min/max: 0.540/0.999. The linear regression analysis of the campaign data set yielded very small intercepts (median: 1.1 pptv; Q1/Q3: −1.1/2.6 pptv; min/max: −14.1/28.0 pptv, and the slopes of the regression lines were close to unity (median: 1.01; Q1/Q3: 0.92/1.10; min/max: 0.72/1.36. The deviation of individual regression slopes from unity was always within the combined

Optimization of biological and instrumental detection of explosives and ignitable liquid residues including canines, SPME/ITMS and GC/MSn

Science.gov (United States)

Furton, Kenneth G.; Harper, Ross J.; Perr, Jeannette M.; Almirall, Jose R.

2003-09-01

and comparisons of limits of detection. These instrumental methods are being optimized in order to detect the same target odor chemicals used by detector dogs to reliably locate explosives and ignitable liquids.

Detection limit calculations for different total reflection techniques

International Nuclear Information System (INIS)

Sanchez, H.J.

2000-01-01

In this work, theoretical calculations of detection limits for different total-reflection techniques are presented.. Calculations include grazing incidence (TXRF) and gracing exit (GEXRF) conditions. These calculations are compared with detection limits obtained for conventional x-ray fluorescence (XRF). In order to compute detection limits the Shiraiwa and Fujino's model to calculate x-ray fluorescence intensities was used. This model made certain assumptions and approximations to achieve the calculations, specially in the case of the geometrical conditions of the sample, and the incident and takeoff beams. Nevertheless the calculated data of detection limits for conventional XRF and total-reflection XRF show a good agreement with previous results. The model proposed here allows to analyze the different sources of background and the influence of the excitation geometry, which contribute to the understanding of the physical processes involved in the XRF analysis by total reflection. Finally, a comparison between detection limits in total-reflection analysis at grazing incidence and at grazing exit is carried out. Here a good agreement with the theoretical predictions of the reversibility principle is found, showing that detection limits are similar for both techniques. (author)

Developing the Cleanliness Requirements for an Organic-detection Instrument MOMA-MS

Science.gov (United States)

Perry, Radford; Canham, John; Lalime, Erin

2015-01-01

The cleanliness requirements for an organic-detection instrument, like the Mars Organic Molecule Analyzer Mass Spectrometer (MOMA-MS), on a Planetary Protection Class IVb mission can be extremely stringent. These include surface molecular and particulate, outgassing, and bioburden. The prime contractor for the European Space Agencys ExoMars 2018 project, Thales Alenia Space Italy, provided requirements based on a standard, conservative approach of defining limits which yielded levels that are unverifiable by standard cleanliness verification methods. Additionally, the conservative method for determining contamination surface area uses underestimation while conservative bioburden surface area relies on overestimation, which results in inconsistencies for the normalized reporting. This presentation will provide a survey of the challenge to define requirements that can be reasonably verified and still remain appropriate to the core science of the ExoMars mission.

Study on Instrument Fault Detection using OLM Techniques for PHM Application in NPPs

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Hwan; Park, Gee Yong; Kim, Jung Taek; Hur, Seop [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

The diagnosis system is relatively being mature owing to many research. Among the various models, this paper introduces some On-Line Monitoring (OLM) models for instrument health monitoring and review applicability on NPPs. In recent years, many researchers are being focused on the prognostics which is predicting the future failure of instruments or equipment by using the status monitoring data. By using the prognostic techniques, we can expect a lot of advantages such as ease of control, power optimization, or optimal use of maintenance resources. And we have performed the test for detecting fault of safety-critical instruments and analyzed the fault detection sensitivity for various instrument failure modes using OLM techniques. OLM techniques using data-driven based model such AAKR or AANN can be useful tools for securing integrity of safety-critical instrument that should always keep healthy conditions for the plant safety.

The design of a simple radon-detecting instrument based on MCU

International Nuclear Information System (INIS)

Du Genyuan; Qiu Yingyu; Zhang Jiang

2007-01-01

Introduction are given on the internal composition of the radon-detecting instrument based on MCU and the working of the real electric circuit. The single-chip microcomputer P89C58 of PHILIPS is adopted as the micro-controller of the instrument, realizing such functions as counting input pulses within fixed time, data processing, liquid crystal display, keyboard interface, serial communication, etc. The instrument turns out to be low in work consumption, with relatively high degree of concentration and computerization, and is recommended for field operations. (authors)

The design of a simple radon-detecting instrument based on MCU

International Nuclear Information System (INIS)

Du Genyuan; Chen Jianjun; Zhang Jiang

2008-01-01

Introduction are given on the internal composition of the radon-detecting instrument based on MCU and the working of the real electric circuit. The single-chip microcomputer P89C58 of PHILIPS is adopted as the micro-controller of the instrument, realizing such functions as counting input pulses within fixed time, data processing, liquid crystal display, keyboard interface, serial communication, etc. The instrument turns out to be low in work consumption, with relatively high degree of concentration and computerization, and is recommended for field operations. (authors)

Raman Life Detection Instrument Development for Icy Worlds

Science.gov (United States)

Thomson, Seamus; Allen, A'Lester; Gutierrez, Daniel; Quinn, Richard C.; Chen, Bin; Koehne, Jessica E.

2017-01-01

The objective of this project is to develop a compact, high sensitivity Raman sensor for detection of life signatures in a flow cell configuration to enable bio-exploration and life detection during future mission to our Solar Systems Icy Worlds. The specific project objectives are the following: 1) Develop a Raman spectroscopy liquid analysis sensor for biosignatures; 2) Demonstrate applicability towards a future Enceladus or other Icy Worlds missions; 3) Establish key parameters for integration with the ARC Sample Processor for Life on Icy Worlds (SPLIce); 4) Position ARC for a successful response to upcoming Enceladus or other Icy World mission instrument opportunities.

Real-time instrument-failure detection in the LOFT pressurizer using functional redundancy

International Nuclear Information System (INIS)

Tylee, J.L.

1982-07-01

The functional redundancy approach to detecting instrument failures in a pressurized water reactor (PWR) pressurizer is described and evaluated. This real-time method uses a bank of Kalman filters (one for each instrument) to generate optimal estimates of the pressurizer state. By performing consistency checks between the output of each filter, failed instruments can be identified. Simulation results and actual pressurizer data are used to demonstrate the capabilities of the technique

Soil monitoring instrumentation

International Nuclear Information System (INIS)

Umbarger, C.J.

1980-01-01

The Los Alamos Scientific Laboratory (LASL) has an extensive program for the development of nondestructive assay instrumentation for the quantitative analysis of transuranic (TRU) materials found in bulk solid wastes generated by Department of Energy facilities and by the commercial nuclear power industry. Included are wastes generated in decontamination and decommissioning of outdated nuclear facilities as well as wastes from old waste burial ground exhumation programs. The assay instrumentation is designed to have detection limits below 10 nCi/g wherever practicable. Because of the topic of this workshop, only the assay instrumentation applied specifically to soil monitoring will be discussed here. Four types of soil monitors are described

Methodology applied by the Petroleum, Natural Gas and Bio fuels National Agency for detection of cartels - their limits and perspectives; Metodology adotada pela Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis para detectecao de carteis - seus limites e perspectives

Energy Technology Data Exchange (ETDEWEB)

Pedra, Douglas Pereira; Sales, Orlando de Araujo Vilela; Baran, Patricia Huguenin; Paiva, Rodrigo Milao de [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Rio de Janeiro, RJ (Brazil). Regulacao de Petroleo, seus Derivados, Alcool Combustivel e Gas Natural; Bicalho, Lucia Maria de Oliveira Navegantes [Universidade Federal do Rio de Janeiro (PPE/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Planejamento Energetico

2010-07-01

This paper presents the present methodology used by the Defense Competition Coordination of the Petroleum National Agency for detection of vestiges of cartels in the Brazilian fuel market, their limits, in view of the instruments presently at the disposal of the Agency and perspectives of modification from the eventual availability of new instruments.

Lower limit of detection: definition and elaboration of a proposed position for radiological effluent and environmental measurements

International Nuclear Information System (INIS)

Currie, L.A.

1984-09-01

A manual is provided to define and illustrate a proposed use of the Lower Limit of Detection (LLD) for Radiological Effluent and Environmental Measurements. The manual contains a review of information regarding LLD practices gained from site visits; a review of the literature and a summary of basic principles underlying the concept of detection in Nuclear and Analytical Chemistry; a detailed presentation of the application of LLD principles to a range of problem categories (simple counting to multinuclide spectroscopy), including derivations, equations, and numerical examples; and a brief examination of related issues such as reference samples, numerical quality control, and instrumental limitations. An appendix contains a summary of notation and terminology, a bibliography, and worked-out examples. 100 references, 10 figures, 7 tables

Activation analysis. Detection limits

International Nuclear Information System (INIS)

Revel, G.

1999-01-01

Numerical data and limits of detection related to the four irradiation modes, often used in activation analysis (reactor neutrons, 14 MeV neutrons, photon gamma and charged particles) are presented here. The technical presentation of the activation analysis is detailed in the paper P 2565 of Techniques de l'Ingenieur. (A.L.B.)

The development of special equipment amplitude detection instrument based on DSP

International Nuclear Information System (INIS)

Dai Sidan; Chen Ligang; Lan Peng; Wang Huiting; Zhang Liangxu; Wang Lin

2014-01-01

Development and industrial application of special equipment plays an important role in the development of nuclear energy process. Equipment development process need to do a lot of tests, amplitude detection is a key test,it can analysis the device's electromechanical and physical properties. In the industrial application, the amplitude detection can effectively reflect the operational status of the current equipment, the equipment can also be a certain degree of fault diagnosis, identify problems in a timely manner. The main development target in this article is amplitude detection of special equipment. This article describes the development of special equipment amplitude detection instrument. The instrument uses a digital signal processor (DSP) as the central processing unit, and uses the DSP + CPLD + high-speed AD technology to build a complete set of high-precision signal acquisition and analysis processing systems, rechargeable lithium battery as the powered device. It can do a online monitoring of special equipment amplitude, speed parameters by acquiring and analysing the tachometer signal in the special equipment, and locally display through the LCD screen. (authors)

Development of an alpha scattering instrument for heavy element detection in surface materials. Final report

International Nuclear Information System (INIS)

Turkevich, A.L.; Economou, T.; Blume, E.; Anderson, W.

1974-12-01

The development and characteristics of a portable instrument for detecting and measuring the amounts of lead in painted surfaces are discussed. The instrument is based on the ones used with the alpha scattering experiment on the Surveyor lunar missions. The principles underlying the instrument are described. It is stated that the performance tests of the instrument were satisfactory. (auth)

Comparison of OH Reactivity Instruments in the Atmosphere Simulation Chamber SAPHIR.

Science.gov (United States)

Fuchs, H.; Novelli, A.; Rolletter, M.; Hofzumahaus, A.; Pfannerstill, E.; Edtbauer, A.; Kessel, S.; Williams, J.; Michoud, V.; Dusanter, S.; Locoge, N.; Zannoni, N.; Gros, V.; Truong, F.; Sarda Esteve, R.; Cryer, D. R.; Brumby, C.; Whalley, L.; Stone, D. J.; Seakins, P. W.; Heard, D. E.; Schoemaecker, C.; Blocquet, M.; Fittschen, C. M.; Thames, A. B.; Coudert, S.; Brune, W. H.; Batut, S.; Tatum Ernest, C.; Harder, H.; Elste, T.; Bohn, B.; Hohaus, T.; Holland, F.; Muller, J. B. A.; Li, X.; Rohrer, F.; Kubistin, D.; Kiendler-Scharr, A.; Tillmann, R.; Andres, S.; Wegener, R.; Yu, Z.; Zou, Q.; Wahner, A.

2017-12-01

Two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016 to compare hydroxyl (OH) radical reactivity (kOH) measurements. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapor, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements is higher for instruments directly detecting hydroxyl radicals (OH), whereas the indirect Comparative Reactivity Method (CRM) has a higher limit of detection of 2s-1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapor or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected in the chamber to simulate urban and forested environments. Overall, the results show that instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to the reference were observed by CRM instruments in the presence of terpenes and oxygenated organic compounds. In some of these experiments, only a small fraction of the reactivity is detected. The accuracy of CRM measurements is most likely limited by the corrections that need to be applied in order to account for known effects of, for example, deviations from pseudo-first order conditions, nitrogen oxides or water vapor on the measurement

Standard practice for evaluating performance characteristics of ultrasonic Pulse-Echo testing instruments and systems without the use of electronic measurement instruments

CERN Document Server

American Society for Testing and Materials. Philadelphia

2011-01-01

1.1 This practice describes procedures for evaluating the following performance characteristics of ultrasonic pulse-echo examination instruments and systems: Horizontal Limit and Linearity; Vertical Limit and Linearity; Resolution - Entry Surface and Far Surface; Sensitivity and Noise; Accuracy of Calibrated Gain Controls. Evaluation of these characteristics is intended to be used for comparing instruments and systems or, by periodic repetition, for detecting long-term changes in the characteristics of a given instrument or system that may be indicative of impending failure, and which, if beyond certain limits, will require corrective maintenance. Instrument characteristics measured in accordance with this practice are expressed in terms that relate to their potential usefulness for ultrasonic testing. Instrument characteristics expressed in purely electronic terms may be measured as described in E1324. 1.2 Ultrasonic examination systems using pulsed-wave trains and A-scan presentation (rf or video) may be ev...

Calibrate the aerial surveying instrument by the limited surface source and the single point source that replace the unlimited surface source

CERN Document Server

Lu Cun Heng

1999-01-01

It is described that the calculating formula and surveying result is found on the basis of the stacking principle of gamma ray and the feature of hexagonal surface source when the limited surface source replaces the unlimited surface source to calibrate the aerial survey instrument on the ground, and that it is found in the light of the exchanged principle of the gamma ray when the single point source replaces the unlimited surface source to calibrate aerial surveying instrument in the air. Meanwhile through the theoretical analysis, the receiving rate of the crystal bottom and side surfaces is calculated when aerial surveying instrument receives gamma ray. The mathematical expression of the gamma ray decaying following height according to the Jinge function regularity is got. According to this regularity, the absorbing coefficient that air absorbs the gamma ray and the detective efficiency coefficient of the crystal is calculated based on the ground and air measuring value of the bottom surface receiving cou...

Establishment of limits of detection and decision

International Nuclear Information System (INIS)

Mende, O.; Michel, R.

1995-01-01

The purpose of this project was to develop and test procedures to establish limits of decision and detection for spectrometric nuclear radiation measurements. Beside the determination of the limits of application of DIN 25482 part 2 and 5 - both primarily suitable for high resoluted spectra areas -the statistical model was expanded in such a way that henceforth blanks and influences of sample treatment can also be taken into account; the corresponding procedures to calculate the limits of decision and detection have a high precision. Additional procedures of calculation were developed to take the special characteristics of the analysis of complex spectra areas into account. (orig.) [de

Seismic response and damage detection analyses of an instrumented steel moment-framed building

Science.gov (United States)

Rodgers, J.E.; Celebi, M.

2006-01-01

The seismic performance of steel moment-framed buildings has been of particular interest since brittle fractures were discovered at the beam-column connections in a number of buildings following the M 6.7 Northridge earthquake of January 17, 1994. A case study of the seismic behavior of an extensively instrumented 13-story steel moment frame building located in the greater Los Angeles area of California is described herein. Response studies using frequency domain, joint time-frequency, system identification, and simple damage detection analyses are performed using an extensive strong motion dataset dating from 1971 to the present, supported by engineering drawings and results of postearthquake inspections. These studies show that the building's response is more complex than would be expected from its highly symmetrical geometry. The response is characterized by low damping in the fundamental mode, larger accelerations in the middle and lower stories than at the roof and base, extended periods of vibration after the cessation of strong input shaking, beating in the response, elliptical particle motion, and significant torsion during strong shaking at the top of the concrete piers which extend from the basement to the second floor. The analyses conducted indicate that the response of the structure was elastic in all recorded earthquakes to date, including Northridge. Also, several simple damage detection methods employed did not indicate any structural damage or connection fractures. The combination of a large, real structure and low instrumentation density precluded the application of many recently proposed advanced damage detection methods in this case study. Overall, however, the findings of this study are consistent with the limited code-compliant postearthquake intrusive inspections conducted after the Northridge earthquake, which found no connection fractures or other structural damage. ?? ASCE.

Design and Elementary Evaluation of a Highly-Automated Fluorescence-Based Instrument System for On-Site Detection of Food-Borne Pathogens

Directory of Open Access Journals (Sweden)

Zhan Lu

2017-02-01

Full Text Available A simple, highly-automated instrument system used for on-site detection of foodborne pathogens based on fluorescence was designed, fabricated, and preliminarily tested in this paper. A corresponding method has been proved effective in our previous studies. This system utilizes a light-emitting diode (LED to excite fluorescent labels and a spectrometer to record the fluorescence signal from samples. A rotation stage for positioning and switching samples was innovatively designed for high-throughput detection, ten at most in one single run. We also developed software based on LabVIEW for data receiving, processing, and the control of the whole system. In the test of using a pure quantum dot (QD solution as a standard sample, detection results from this home-made system were highly-relevant with that from a well-commercialized product and even slightly better reproducibility was found. And in the test of three typical kinds of food-borne pathogens, fluorescence signals recorded by this system are highly proportional to the variation of the sample concentration, with a satisfied limit of detection (LOD (nearly 102–103 CFU·mL−1 in food samples. Additionally, this instrument system is low-cost and easy-to-use, showing a promising potential for on-site rapid detection of food-borne pathogens.

Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

Directory of Open Access Journals (Sweden)

Peeyush Sahay

2009-10-01

Full Text Available Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS, cavity ringdown spectroscopy (CRDS, integrated cavity output spectroscopy (ICOS, cavity enhanced absorption spectroscopy (CEAS, cavity leak-out spectroscopy (CALOS, photoacoustic spectroscopy (PAS, quartz-enhanced photoacoustic spectroscopy (QEPAS, and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS. Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis.

Mineralogy and Astrobiology Detection Using Laser Remote Sensing Instrument

Science.gov (United States)

Abedin, M. Nurul; Bradley, Arthur T.; Sharma, Shiv K.; Misra, Anupam K.; Lucey, Paul G.; Mckay, Chistopher P.; Ismail, Syed; Sandford, Stephen P.

2015-01-01

A multispectral instrument based on Raman, laser-induced fluorescence (LIF), laser-induced breakdown spectroscopy (LIBS), and a lidar system provides high-fidelity scientific investigations, scientific input, and science operation constraints in the context of planetary field campaigns with the Jupiter Europa Robotic Lander and Mars Sample Return mission opportunities. This instrument conducts scientific investigations analogous to investigations anticipated for missions to Mars and Jupiter's icy moons. This combined multispectral instrument is capable of performing Raman and fluorescence spectroscopy out to a >100 m target distance from the rover system and provides single-wavelength atmospheric profiling over long ranges (>20 km). In this article, we will reveal integrated remote Raman, LIF, and lidar technologies for use in robotic and lander-based planetary remote sensing applications. Discussions are focused on recently developed Raman, LIF, and lidar systems in addition to emphasizing surface water ice, surface and subsurface minerals, organics, biogenic, biomarker identification, atmospheric aerosols and clouds distributions, i.e., near-field atmospheric thin layers detection for next robotic-lander based instruments to measure all the above-mentioned parameters. OCIS codes: (120.0280) Remote sensing and sensors; (130.0250) Optoelectronics; (280.3640) Lidar; (300.2530) Fluorescence, laser-induced; (300.6450) Spectroscopy, Raman; (300.6365) Spectroscopy, laser induced breakdown

Limits of qualitative detection and quantitative determination

International Nuclear Information System (INIS)

Curie, L.A.

1976-01-01

The fact that one can find a series of disagreeing and limiting definitions of the detection limit leads to the reinvestigation of the problems of signal detection and signal processing in analytical and nuclear chemistry. Three cut-off levels were fixed: Lsub(C) - the net signal level (sensitivity of the equipment), above which an observed signal can be reliably recognized as 'detected'; Lsub(D) - the 'true' net signal level, from which one can a priori expect a detection; Lsub(Q) - the level at which the measuring accuracy is sufficient for quantitative determination. Exact definition equations as well as a series of working formulae are given for the general analytical case and for the investigation of radioactivity. As it is assumed that the radioactivity of the Poisson distribution is determined, it is dealt with in such a manner that precise limits can be derived for short-lived and long-lived radionuclides with or without disturbance. The fundamentals are made clear by simple examples for spectrophotometry and radioactivity and by a complicated example for activation analysis in which one must choose between alternative nuclear reactions. (orig./LH) [de

Buried pipeline leak-detection technique and instruments using radioactive tracers

International Nuclear Information System (INIS)

Zhou Shuxuan; Lu Qingqian; Tang Yonghua

1987-01-01

For detecting and locating leaks on buried pipelines, a leak-detection technique and related instruments have been developed. Some quantity of fluid mixed with a radioactive tracer is injected. After the pipeline is cleaned, a leak-detector is put into and moves along the pipline to monitor the leaked radioactivity and to record both the radioactive signal and the time signal on a magnetic tape. From the signal curves, it can be judged whether there are any leaks on the pipeline and, if any, where they are

The design of a simple portable γ ray detecting instrument based on MCU

International Nuclear Information System (INIS)

Liu Chunmei; Cao Wen; Zhang Jiang

2008-01-01

The internal composition of the γ ray detecting instrument based on MCU and the working of the real electric circuit are introduced. The single-chip microcomputer of PHILIPS is adopted as the micro-controller of the instrument, realizing such functions as counting input pulses within fixed time, data processing, liquid crystal display, keyboard interface, serial communication, etc. The instrument turns out to be low in work consumption, with relatively high degree of concentration and computerization, and is recommended for field operations. (authors)

On the lower of limit detection of radiometric systems

International Nuclear Information System (INIS)

Kamburov, H.; Boneva, S.

1983-01-01

The existing definitions of the quantity Asub(min), the lower detection limit, introduced as a characteristic of the sensitivity of radiometric systems are reviewed. A convenient way is found for comparing the different definitions by showing that each definition is connected with a specific value of the probability a of Type I error. The detection limits are calculated for a normal and Poisson distributions of the measured quantities. A criterion is proposed for the applicability of the normal distiribution to the problem of determining the lower detection limit

Determination of detection limits for a VPD ICPMS method of analysis; Determination des limites de detection d'une methode d'analyse VPD ICPMS

Energy Technology Data Exchange (ETDEWEB)

Badard, M.; Veillerot, M

2007-07-01

This training course report presents the different methods of detection and quantifying of metallic impurities in semiconductors. One of the most precise technique is the collection of metal impurities by vapor phase decomposition (VPD) followed by their analysis by ICPMS (inductively coupled plasma mass spectrometry). The study shows the importance of detection limits in the domain of chemical analysis and the way to determine them for the ICPMS analysis. The results found on detection limits are excellent. Even if the detection limits reached with ICPMS performed after manual or automatic VPD are much higher than detection limits of ICPMS alone, this method remains one of the most sensible for ultra-traces analysis. (J.S.)

Limits of Tumor Detectability in Nuclear Medicine and PET

Directory of Open Access Journals (Sweden)

Yusuf Emre Erdi

2012-04-01

Full Text Available Objective: Nuclear medicine is becoming increasingly important in the early detection of malignancy. The advantage of nuclear medicine over other imaging modalities is the high sensitivity of the gamma camera. Nuclear medicine counting equipment has the capability of detecting levels of radioactivity which exceed background levels by as little as 2.4 to 1. This translates to only a few hundred counts per minute on a regular gamma camera or as few as 3 counts per minute when using coincidence detection on a positron emission tomography (PET camera. Material and Methods: We have experimentally measured the limits of detectability using a set of hollow spheres in a Jaszczak phantom at various tumor-to-background ratios. Imaging modalities for this work were (1 planar, (2 SPECT, (3 PET, and (4 planar camera with coincidence detection capability (MCD. Results: When there is no background (infinite contrast activity present, the detectability of tumors is similar for PET and planar imaging. With the presence of the background activity , PET can detect objects in an order of magnitude smaller in size than that can be seen by conventional planar imaging especially in the typical clinical low (3:1 T/B ratios. The detection capability of the MCD camera lies between a conventional nuclear medicine (planar / SPECT scans and the detection capability of a dedicated PET scanner Conclusion: Among nuclear medicine’s armamentarium, PET is the closest modality to CT or MR imaging in terms of limits of detection. Modern clinical PET scanners have a resolution limit of 4 mm, corresponding to the detection of tumors with a volume of 0.2 ml (7 mm diameter in 5:1 T/B ratio. It is also possible to obtain better resolution limits with dedicated brain and animal scanners. The future holds promise in development of new detector materials, improved camera design, and new reconstruction algorithms which will improve sensitivity, resolution, contrast, and thereby further

A critical appraisal of instruments to measure outcomes of interprofessional education.

Science.gov (United States)

Oates, Matthew; Davidson, Megan

2015-04-01

Interprofessional education (IPE) is believed to prepare health professional graduates for successful collaborative practice. A range of instruments have been developed to measure the outcomes of IPE. An understanding of the psychometric properties of these instruments is important if they are to be used to measure the effectiveness of IPE. This review set out to identify instruments available to measure outcomes of IPE and collaborative practice in pre-qualification health professional students and to critically appraise the psychometric properties of validity, responsiveness and reliability against contemporary standards for instrument design. Instruments were selected from a pool of extant instruments and subjected to critical appraisal to determine whether they satisfied inclusion criteria. The qualitative and psychometric attributes of the included instruments were appraised using a checklist developed for this review. Nine instruments were critically appraised, including the widely adopted Readiness for Interprofessional Learning Scale (RIPLS) and the Interdisciplinary Education Perception Scale (IEPS). Validity evidence for instruments was predominantly based on test content and internal structure. Ceiling effects and lack of scale width contribute to the inability of some instruments to detect change in variables of interest. Limited reliability data were reported for two instruments. Scale development and scoring protocols were generally reported by instrument developers, but the inconsistent application of scoring protocols for some instruments was apparent. A number of instruments have been developed to measure outcomes of IPE in pre-qualification health professional students. Based on reported validity evidence and reliability data, the psychometric integrity of these instruments is limited. The theoretical test construction paradigm on which instruments have been developed may be contributing to the failure of some instruments to detect change in

Design of improved detection instrumentation for the annulus gas system for wolsong 2

International Nuclear Information System (INIS)

Kim, Seog Nam; Koo, Jun Mo; Chang, Ik Ho; Jung, Ho Chang; Han, Sang Joon

1996-01-01

The improved and advanced Annulus Gas System (AGS) has been developed for Wolsong 2 to satisfy the requirements of the regulatory body. The Atomic Energy Control Board (AECB) required a shorter detection time following a small leak from a pressure tube and/or calandria tube. This paper describes licensing requirements, functional requirements and detail design description for the AGS. The Wolsong unit No. 1 AGS was designed to operate as a stagnant system normally requiring only pressure regulation and having provisions for purging. The improved AGS involves the adoption of gas recirculation in AGS, duplication of dew point indicators with additional instrumentation and sampling provisions to prompt operator action. The improved system operates in the recirculation mode with continuous dew point measurement for leak detection. An AGS with improved detection instrumentation is provided. 8 refs., 3 figs. (author)

Atmospheric boundary layer CO2 remote sensing with a direct detection LIDAR instrument based on a widely tunable optical parametric source.

Science.gov (United States)

Cadiou, Erwan; Mammez, Dominique; Dherbecourt, Jean-Baptiste; Gorju, Guillaume; Pelon, Jacques; Melkonian, Jean-Michel; Godard, Antoine; Raybaut, Myriam

2017-10-15

We report on the capability of a direct detection differential absorption lidar (DIAL) for range resolved and integrated path (IPDIAL) remote sensing of CO 2 in the atmospheric boundary layer (ABL). The laser source is an amplified nested cavity optical parametric oscillator (NesCOPO) emitting approximately 8 mJ at the two measurement wavelengths selected near 2050 nm. Direct detection atmospheric measurements are taken from the ground using a 30 Hz frequency switching between emitted wavelengths. Results show that comparable precision measurements are achieved in DIAL and IPDIAL modes (not better than a few ppm) on high SNR targets such as near range ABL aerosol and clouds, respectively. Instrumental limitations are analyzed and degradation due to cloud scattering variability is discussed to explain observed DIAL and IPDIAL limitations.

Development of international standards for instrumentation used for detection of illicit trafficking of radioactive material

International Nuclear Information System (INIS)

Voytchev, M.; Chiaro, P.; Radev, R.

2006-01-01

Subcommittee 45 B 'Radiation Protection Instrumentation' of the International Electrotechnical Commission (I.E.C.) is charged with the development of international standards for instrumentation used for monitoring of illicit trafficking of radioactive material through international boarders and territories, as well as inside countries. Currently three I.E.C. standards are in advanced stages of development. They are expected to be approved and published in 2006-2007. The international participation and the main characteristics of the following three standards are discussed and presented: I.E.C. 62327 'Hand-held Instruments for the Detection and Identification of Radionuclides and Additionally for the Indication of Ambient Dose Equivalent Rate from Photon Radiation', I.E.C. 62401 'Alarming Personal Radiation Devices for Detection of Illicit Trafficking of Radioactive Material' and I.E.C. 62244 'Installed Radiation Monitors for the Detection of Radioactive and Special Nuclear Materials at National Borders'

Search times and probability of detection in time-limited search

Science.gov (United States)

Wilson, David; Devitt, Nicole; Maurer, Tana

2005-05-01

When modeling the search and target acquisition process, probability of detection as a function of time is important to war games and physical entity simulations. Recent US Army RDECOM CERDEC Night Vision and Electronics Sensor Directorate modeling of search and detection has focused on time-limited search. Developing the relationship between detection probability and time of search as a differential equation is explored. One of the parameters in the current formula for probability of detection in time-limited search corresponds to the mean time to detect in time-unlimited search. However, the mean time to detect in time-limited search is shorter than the mean time to detect in time-unlimited search and the relationship between them is a mathematical relationship between these two mean times. This simple relationship is derived.

Effect of sample matrix composition on INAA sample weights, measurement precisions, limits of detection, and optimum conditions

International Nuclear Information System (INIS)

Guinn, V.P.; Nakazawa, L.; Leslie, J.

1984-01-01

The instrumental neutron activation analysis (INAA) Advance Prediction Computer Program (APCP) is extremely useful in guiding one to optimum subsequent experimental analyses of samples of all types of matrices. By taking into account the contributions to the cumulative Compton-continuum levels from all significant induced gamma-emitting radionuclides, it provides good INAA advance estimates of detectable photopeaks, measurement precisions, concentration lower limits of detection (LOD's) and optimum irradiation/decay/counting conditions - as well as of the very important maximum allowable sample size for each set of conditions calculated. The usefulness and importance of the four output parameters cited in the title are discussed using the INAA APCP outputs for NBS SRM-1632 Coal as the example

The Single Item Literacy Screener: Evaluation of a brief instrument to identify limited reading ability

Directory of Open Access Journals (Sweden)

Chew Lisa D

2006-03-01

Full Text Available Abstract Background Reading skills are important for accessing health information, using health care services, managing one's health and achieving desirable health outcomes. Our objective was to assess the diagnostic accuracy of the Single Item Literacy Screener (SILS to identify limited reading ability, one component of health literacy, as measured by the S-TOFHLA. Methods Cross-sectional interview with 999 adults with diabetes residing in Vermont and bordering states. Participants were randomly recruited from Primary Care practices in the Vermont Diabetes Information System June 2003 – December 2004. The main outcome was limited reading ability. The primary predictor was the SILS. Results Of the 999 persons screened, 169 (17% had limited reading ability. The sensitivity of the SILS in detecting limited reading ability was 54% [95% CI: 47%, 61%] and the specificity was 83% [95% CI: 81%, 86%] with an area under the Receiver Operating Characteristics Curve (ROC of 0.73 [95% CI: 0.69, 0.78]. Seven hundred seventy (77% screened negative on the SILS and 692 of these subjects had adequate reading skills (negative predictive value = 0.90 [95% CI: 0.88, 0.92]. Of the 229 who scored positive on the SILS, 92 had limited reading ability (positive predictive value = 0.4 [95% CI: 0.34, 0.47]. Conclusion The SILS is a simple instrument designed to identify patients with limited reading ability who need help reading health-related materials. The SILS performs moderately well at ruling out limited reading ability in adults and allows providers to target additional assessment of health literacy skills to those most in need. Further study of the use of the SILS in clinical settings and with more diverse populations is warranted.

Development of international standards for instrumentation used for detection of illicit trafficking of radioactive material

Energy Technology Data Exchange (ETDEWEB)

Voytchev, M. [Institut de Radioprotection et de Surete Nucleaire (IRSN/DSU/SERAC/CTHIR), 91 - Gif sur Yvette (France); Chiaro, P. [Oak Ridge National Lab., TN (United States); Radev, R. [LLNL, Livermore, CA (United States)

2006-07-01

Subcommittee 45 B 'Radiation Protection Instrumentation' of the International Electrotechnical Commission (I.E.C.) is charged with the development of international standards for instrumentation used for monitoring of illicit trafficking of radioactive material through international boarders and territories, as well as inside countries. Currently three I.E.C. standards are in advanced stages of development. They are expected to be approved and published in 2006-2007. The international participation and the main characteristics of the following three standards are discussed and presented: I.E.C. 62327 'Hand-held Instruments for the Detection and Identification of Radionuclides and Additionally for the Indication of Ambient Dose Equivalent Rate from Photon Radiation', I.E.C. 62401 'Alarming Personal Radiation Devices for Detection of Illicit Trafficking of Radioactive Material' and I.E.C. 62244 'Installed Radiation Monitors for the Detection of Radioactive and Special Nuclear Materials at National Borders'.

Radioisotope tracer instrument and its application to the detection of the groundwater parameters

International Nuclear Information System (INIS)

Chen Jiansheng

1988-01-01

The application of radioisotope tracer technique and probe can result in the detection of groundwater flow direction, flow velocity and vertical currents in one single well. The tracer probe consists of the source injector and the components related with direction detection, location and velocity measurement. The nuclear detector employs a thermoluminescence detector (TLD) and a direct reading ionization chamber (IC) for the detection of flow direction and also employs a new method of photofluorography location for the determination of the probe's northern or southern position in the well, thereby greatly simplifying the design of the direction-detecting probe. The velocity measuring section includes ground receiving instruments and meters for conducting point or whole-borehole measurement. It is also possible to carry out interconnection tests and dispersion tests. With the applications to the ascertaining of the groundwater distribution in the karst region as well as the execution of the dispersion tests related with environmental protection and so on, it has been confirmed that the radioisotope tracer instrument has a broad scope of application and practicability. (author). 5 refs, 6 figs

Methodologies for the practical determination and use of method detection limits

International Nuclear Information System (INIS)

Rucker, T.L.

1995-01-01

Method detection limits have often been misunderstood and misused. The basic definitions developed by Lloyd Currie and others have been combined with assumptions that are inappropriate for many types of radiochemical analyses. A partical way for determining detection limits based on Currie's basic definition is presented that removes the reliance on assumptions and that accounts for the total measurement uncertainty. Examples of proper and improper use of detection limits are also presented, including detection limits reported by commercial software for gamma spectroscopy and neutron activation analyses. (author) 6 refs.; 2 figs

Reactor instrumentation and control

International Nuclear Information System (INIS)

Wach, D.; Beraha, D.

1980-01-01

The methods for measuring radiation are shortly reviewed. The instrumentation for neutron flux measurement is classified into out-of-core and in-core instrumentation. The out-of-core instrumentation monitors the operational range from the subcritical reactor to full power. This large range is covered by several measurement channels which derive their signals from counter tubes and ionization chambers. The in-core instrumentation provides more detailed information on the power distribution in the core. The self-powered neutron detectors and the aeroball system in PWR reactors are discussed. Temperature and pressure measurement devices are briefly discussed. The different methods for leak detection are described. In concluding the plant instrumentation part some new monitoring systems and analysis methods are presented: early failure detection methods by noise analysis, acoustic monitoring and vibration monitoring. The presentation of the control starts from an qualitative assessment of the reactor dynamics. The chosen control strategy leads to the definition of the part-load diagram, which provides the set-points for the different control systems. The tasks and the functions of these control systems are described. In additiion to the control, a number of limiting systems is employed to keep the reactor in a safe operating region. Finally, an outlook is given on future developments in control, concerning mainly the increased application of process computers. (orig./RW)

No evidence for an item limit in change detection.

Directory of Open Access Journals (Sweden)

Shaiyan Keshvari

Full Text Available Change detection is a classic paradigm that has been used for decades to argue that working memory can hold no more than a fixed number of items ("item-limit models". Recent findings force us to consider the alternative view that working memory is limited by the precision in stimulus encoding, with mean precision decreasing with increasing set size ("continuous-resource models". Most previous studies that used the change detection paradigm have ignored effects of limited encoding precision by using highly discriminable stimuli and only large changes. We conducted two change detection experiments (orientation and color in which change magnitudes were drawn from a wide range, including small changes. In a rigorous comparison of five models, we found no evidence of an item limit. Instead, human change detection performance was best explained by a continuous-resource model in which encoding precision is variable across items and trials even at a given set size. This model accounts for comparison errors in a principled, probabilistic manner. Our findings sharply challenge the theoretical basis for most neural studies of working memory capacity.

Moving your laboratories to the field – Advantages and limitations of the use of field portable instruments in environmental sample analysis

Energy Technology Data Exchange (ETDEWEB)

Gałuszka, Agnieszka, E-mail: Agnieszka.Galuszka@ujk.edu.pl [Geochemistry and the Environment Division, Institute of Chemistry, Jan Kochanowski University, 15G Świętokrzyska St., 25-406 Kielce (Poland); Migaszewski, Zdzisław M. [Geochemistry and the Environment Division, Institute of Chemistry, Jan Kochanowski University, 15G Świętokrzyska St., 25-406 Kielce (Poland); Namieśnik, Jacek [Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology (GUT), 11/12 G. Narutowicz St., 80-233 Gdańsk (Poland)

2015-07-15

The recent rapid progress in technology of field portable instruments has increased their applications in environmental sample analysis. These instruments offer a possibility of cost-effective, non-destructive, real-time, direct, on-site measurements of a wide range of both inorganic and organic analytes in gaseous, liquid and solid samples. Some of them do not require the use of reagents and do not produce any analytical waste. All these features contribute to the greenness of field portable techniques. Several stationary analytical instruments have their portable versions. The most popular ones include: gas chromatographs with different detectors (mass spectrometer (MS), flame ionization detector, photoionization detector), ultraviolet–visible and near-infrared spectrophotometers, X-ray fluorescence spectrometers, ion mobility spectrometers, electronic noses and electronic tongues. The use of portable instruments in environmental sample analysis gives a possibility of on-site screening and a subsequent selection of samples for routine laboratory analyses. They are also very useful in situations that require an emergency response and for process monitoring applications. However, quantification of results is still problematic in many cases. The other disadvantages include: higher detection limits and lower sensitivity than these obtained in laboratory conditions, a strong influence of environmental factors on the instrument performance and a high possibility of sample contamination in the field. This paper reviews recent applications of field portable instruments in environmental sample analysis and discusses their analytical capabilities. - Highlights: • Field portable instruments are widely used in environmental sample analysis. • Field portable instruments are indispensable for analysis in emergency response. • Miniaturization of field portable instruments reduces resource consumption. • In situ analysis is in agreement with green analytical chemistry

Moving your laboratories to the field – Advantages and limitations of the use of field portable instruments in environmental sample analysis

International Nuclear Information System (INIS)

Gałuszka, Agnieszka; Migaszewski, Zdzisław M.; Namieśnik, Jacek

2015-01-01

The recent rapid progress in technology of field portable instruments has increased their applications in environmental sample analysis. These instruments offer a possibility of cost-effective, non-destructive, real-time, direct, on-site measurements of a wide range of both inorganic and organic analytes in gaseous, liquid and solid samples. Some of them do not require the use of reagents and do not produce any analytical waste. All these features contribute to the greenness of field portable techniques. Several stationary analytical instruments have their portable versions. The most popular ones include: gas chromatographs with different detectors (mass spectrometer (MS), flame ionization detector, photoionization detector), ultraviolet–visible and near-infrared spectrophotometers, X-ray fluorescence spectrometers, ion mobility spectrometers, electronic noses and electronic tongues. The use of portable instruments in environmental sample analysis gives a possibility of on-site screening and a subsequent selection of samples for routine laboratory analyses. They are also very useful in situations that require an emergency response and for process monitoring applications. However, quantification of results is still problematic in many cases. The other disadvantages include: higher detection limits and lower sensitivity than these obtained in laboratory conditions, a strong influence of environmental factors on the instrument performance and a high possibility of sample contamination in the field. This paper reviews recent applications of field portable instruments in environmental sample analysis and discusses their analytical capabilities. - Highlights: • Field portable instruments are widely used in environmental sample analysis. • Field portable instruments are indispensable for analysis in emergency response. • Miniaturization of field portable instruments reduces resource consumption. • In situ analysis is in agreement with green analytical chemistry

Determination of detection limits for a VPD ICPMS method of analysis

International Nuclear Information System (INIS)

Badard, M.; Veillerot, M.

2007-01-01

This training course report presents the different methods of detection and quantifying of metallic impurities in semiconductors. One of the most precise technique is the collection of metal impurities by vapor phase decomposition (VPD) followed by their analysis by ICPMS (inductively coupled plasma mass spectrometry). The study shows the importance of detection limits in the domain of chemical analysis and the way to determine them for the ICPMS analysis. The results found on detection limits are excellent. Even if the detection limits reached with ICPMS performed after manual or automatic VPD are much higher than detection limits of ICPMS alone, this method remains one of the most sensible for ultra-traces analysis. (J.S.)

Importance of the lower limit of detection in radiological safety

International Nuclear Information System (INIS)

Rafael Terol T.; Hermenegildo Maldonado M.

1991-01-01

The concept of the Lower Limit of Detection (LLD) it contributes in the solution of some problems related with the radiological safety, such as the realization of the tests of flight of the sealed radioactive sources; the determination of radioisotopes in environmental samples; the estimate of present radionuclides in polluted foods; in general, the detection of small quantities of radioactive materials present in materials of use or consumption by part of the man in his daily life; as the one Lower Limit of Detection is related with topics of statistics, in this work a small review of them is made, it was superficially discussed the mensuration problems related with the establishment of the Lower Limit of Detection

Confirmation of identity and detection limit in neutron activation analysis

International Nuclear Information System (INIS)

Yustina Tri Handayani; Slamet Wiyuniati; Tulisna

2010-01-01

Neutron Activation Analysis (NAA) based on neutron capture by nuclides. Of the various possibilities of radionuclides that occur, radionuclides and gamma radiation which provides the identity of the element were analyzed and the best sensitivity should be determined. Confirmation for elements in sediment samples was done theoretically and experimentally. The result of confirmation shows that Al, V, Cr K, Na, Ca and Zn were analyzed based on radionuclides of Al-28, V-52, Cr-51 , K-42, Na-24, Ca-48, Zn-65. Elements of Mg, Mn, Fe, Co were analyzed based on radionuclides of Mg-27, Mn-56, Fe-59, Co-60 through peak which the highest value of combined probability of radiation emission and efficiency. Cu can be analyzed through Cu-64 or Cu-66, but the second is more sensitive. Detection limit is determined at a certain measurement conditions carried out by a laboratory. Detection limit in the NAA is determined based on the Compton continue area by Curie method. The detection limit of Al, V, Ca, Mg, Mn, As, K, Na, Mg, Ce, Co, Cr, Fe, La, Sc, and Zn in sediment samples are 240, 27, 4750, 2600, 21, 3.3 , 75, 1.4, 1.8, 0.5, 2.7, 29, 1, 0.05, and 37 ppm. Analysis of Cu in sediments which concentrations of 98.6 ppm, Cu-66 is not detected. Tests using pure standard solutions of Cu obtained detection limit of 0.12 µg, or 7.9 ppm in samples of 15 mg. In general, the detection limit obtained was higher than the detection limit of the reference, it was caused by the differences in the sample matrix and analytical conditions. (author)

The Development and Deployment of a Ground-Based, Laser-Induced Fluorescence Instrument for the In Situ Detection of Iodine Monoxide Radicals

Science.gov (United States)

Thurlow, M. E.; Co, D. T.; O'Brien, A. S.; Hannun, R. A.; Lapson, L. B.; Hanisco, T. F.; Anderson, J. G.

2014-01-01

High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 1012. The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A23/2 (v = 2) ? X23/2 (v = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

Instrument for detecting gas bubbles in sodium filled pipework

Energy Technology Data Exchange (ETDEWEB)

Stapleton, D

1973-08-01

An instrument employing an electromagnetic sensor is described. Gas bubbles down to 0.5 mm diameter can be detected in sodium filled pipework of 1 in. nominal bore at temperatures up to 400 deg C. Installation of the sensing head involves no break in the integrity of the pipework. Facilities to enable bubble size discrimination, bubble counting and timing pulse generation are provided in the signal processing unit. Initial operating experience has been gained on a sodium loop used for gas entrainment studies. (auth)

EFFECTIVENESS AND LIMITATIONS OF MONETARY POLICY INSTRUMENTS IN ROMANIA AND THE EUROPEAN UNION

Directory of Open Access Journals (Sweden)

Zina CIORAN

2014-12-01

Full Text Available The complexity of the monetary phenomenon as well as the effects that it induces in the social and economic life of the countries around the world have represented and still represent the subject of much controversy and dispute. The current forms of the monetary circulation organization in different countries, internationally as well, represent the result of a continuous process of changes and innovations in the monetary area. The purpose of this article is to present aspects of the monetary policy and its instruments which have evolved according to the historical conditions of each period. The paper is also a presentation of effectiveness and limits of the monetary policy instruments and their role in solving the current economic problems for which the governments seek solutions. As a consequence to the analysis, it can be seen that in most cases it uses a mixture of monetary policy instruments because, when acting in a complementary way, they have a higher efficiency.

Quench Detection and Instrumentation for the Tokamak Physics Experiment magnets

International Nuclear Information System (INIS)

Chaplin, M.R.; Hassenzahl, W.V.; Schultz, J.H.

1993-01-01

The design of the Local Instrumentation ampersand Control (I ampersand C) System for the Tokamak Physics Experiment (TPX) superconducting PF ampersand TF magnets is presented. The local I ampersand C system monitors the status of the magnet systems and initiates the proper control sequences to protect the magnets from any foreseeable fault. Local I ampersand C also stores magnet-system data for analysis and archiving. Quench Detection for the TPX magnets must use a minimum of two independent sensing methods and is allowed a detection time of one second. Proposed detection methods include the measurement of; (1) normal-zone resistive voltage, (2) cooling-path helium flow, (3) local temperature in the winding pack, (4) local pressure in the winding pack. Fiber-optic based isolation systems are used to remove high common-mode magnet voltages and eliminate ground loops. The data acquisition and fault-detection systems are computer based. The design of the local I ampersand C system incorporates redundant, fault-tolerant, and/or fail-safe features at all component levels. As part of a quench detection R ampersand D plan, a Quench Detection Model Coil has been proposed to test all detection methods. Initial cost estimates and schedule for the local I ampersand C system are presented

Calibration of UV instruments and limitations on accuracy

International Nuclear Information System (INIS)

Clare, J.F.; Hamlin, J.D.

1993-01-01

Instruments measuring UV radiation may be classified as either spectrometers or broadband monitors; whilst the former determine irradiance as a function of wavelength the latter measure a summation of spectral irradiance weighted by some instrument response function which may be designed to approximate a desired action spectrum. For both classes a proper calibration requires the determination of the instrument's absolute spectral responsivity across the relevant wave-band together with an adequate determination of the wavelengths involved. (author). 7 refs

Methane Flux Estimation from Point Sources using GOSAT Target Observation: Detection Limit and Improvements with Next Generation Instruments

Science.gov (United States)

Kuze, A.; Suto, H.; Kataoka, F.; Shiomi, K.; Kondo, Y.; Crisp, D.; Butz, A.

2017-12-01

Atmospheric methane (CH4) has an important role in global radiative forcing of climate but its emission estimates have larger uncertainties than carbon dioxide (CO2). The area of anthropogenic emission sources is usually much smaller than 100 km2. The Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observing SATellite (GOSAT) has measured CO2 and CH4 column density using sun light reflected from the earth's surface. It has an agile pointing system and its footprint can cover 87-km2 with a single detector. By specifying pointing angles and observation time for every orbit, TANSO-FTS can target various CH4 point sources together with reference points every 3 day over years. We selected a reference point that represents CH4 background density before or after targeting a point source. By combining satellite-measured enhancement of the CH4 column density and surface measured wind data or estimates from the Weather Research and Forecasting (WRF) model, we estimated CH4emission amounts. Here, we picked up two sites in the US West Coast, where clear sky frequency is high and a series of data are available. The natural gas leak at Aliso Canyon showed a large enhancement and its decrease with time since the initial blowout. We present time series of flux estimation assuming the source is single point without influx. The observation of the cattle feedlot in Chino, California has weather station within the TANSO-FTS footprint. The wind speed is monitored continuously and the wind direction is stable at the time of GOSAT overpass. The large TANSO-FTS footprint and strong wind decreases enhancement below noise level. Weak wind shows enhancements in CH4, but the velocity data have large uncertainties. We show the detection limit of single samples and how to reduce uncertainty using time series of satellite data. We will propose that the next generation instruments for accurate anthropogenic CO2 and CH

Evaluation of a Kalman filter based power pressurizer instrument failure detection system implemented on a nuclear power plant training simulator

International Nuclear Information System (INIS)

Seegmiller, D.S.

1984-01-01

The usefulness of a nuclear power plant training simulator for developing and testing modern estimation and control applications for nuclear power plants is demonstrated. A Kalman filter based instrument failure detection technique for a pressurized water reactor pressurizer is implemented on the Department of Energy N Reactor Training Simulator. This real-time failure detection method computes the first two moments (mean and variance) of each element of a normalized filter innovations vector. Failed pressurizer instrumentation can be detected by comparing these moments to the known statistical properties of the steady state, linear Kalman fitler innovations sequence. The capabilities of the detection system are evaluated using simulated plant transients and instrument failures

Stochastic fluctuations and the detectability limit of network communities.

Science.gov (United States)

Floretta, Lucio; Liechti, Jonas; Flammini, Alessandro; De Los Rios, Paolo

2013-12-01

We have analyzed the detectability limits of network communities in the framework of the popular Girvan and Newman benchmark. By carefully taking into account the inevitable stochastic fluctuations that affect the construction of each and every instance of the benchmark, we come to the conclusion that the native, putative partition of the network is completely lost even before the in-degree/out-degree ratio becomes equal to that of a structureless Erdös-Rényi network. We develop a simple iterative scheme, analytically well described by an infinite branching process, to provide an estimate of the true detectability limit. Using various algorithms based on modularity optimization, we show that all of them behave (semiquantitatively) in the same way, with the same functional form of the detectability threshold as a function of the network parameters. Because the same behavior has also been found by further modularity-optimization methods and for methods based on different heuristics implementations, we conclude that indeed a correct definition of the detectability limit must take into account the stochastic fluctuations of the network construction.

Pushing the limits of NAA. Accuracy, uncertainty and detection limits

International Nuclear Information System (INIS)

Greenberg, R.R.

2008-01-01

This paper describes some highlights from the author's efforts to improve neutron activation analysis (NAA) detection limits through development and optimization of radiochemical separations, as well as to improve the overall accuracy of NAA measurements by identifying, quantifying and reducing measurement biases and uncertainties. Efforts to demonstrate the metrological basis of NAA, and to establish it as a 'Primary Method of Measurement' will be discussed. (author)

The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals

Energy Technology Data Exchange (ETDEWEB)

Thurlow, M. E., E-mail: thurlow@huarp.harvard.edu; Hannun, R. A.; Lapson, L. B.; Anderson, J. G. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Co, D. T. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 (United States); O' Brien, A. S. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Hanisco, T. F. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771 (United States)

2014-04-15

High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10{sup 12}. The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A{sup 2}Π{sub 3/2} (v{sup ′} = 2) ← X{sup 2}Π{sub 3/2} (v{sup ″} = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals

International Nuclear Information System (INIS)

Thurlow, M. E.; Hannun, R. A.; Lapson, L. B.; Anderson, J. G.; Co, D. T.; O'Brien, A. S.; Hanisco, T. F.

2014-01-01

High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10 12 . The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A 2 Π 3/2 (v ′ = 2) ← X 2 Π 3/2 (v ″ = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America

Instruments used to assess functional limitations in workers applying for disability benefit : a systematic review

NARCIS (Netherlands)

Spanjer, Jerry; Groothoff, Johan W.; Brouwer, Sandra

2011-01-01

Purpose. To systematically review the quality of the psychometric properties of instruments for assessing functional limitations in workers applying for disability benefit. Method. Electronic searches of Medline, Embase, CINAHL and PsycINFO were performed to identify studies focusing on the

What value, detection limits

International Nuclear Information System (INIS)

Currie, L.A.

1986-01-01

Specific approaches and applications of LLD's to nuclear and ''nuclear-related'' measurements are presented in connection with work undertaken for the U.S. Nuclear Regulatory Commission and the International Atomic Energy Agency. In this work, special attention was given to assumptions and potential error sources, as well as to different types of analysis. For the former, the authors considered random and systematic error associated with the blank and the calibration and sample preparation processes, as well as issues relating to the nature of the random error distributions. Analysis types considered included continuous monitoring, ''simple counting'' involving scalar quantities, and spectrum fitting involving data vectors. The investigation of data matrices and multivariate analysis is also described. The most important conclusions derived from this study are: that there is a significant lack of communication and compatibility resulting from diverse terminology and conceptual bases - including no-basis ''ad hoc'' definitions; that the distinction between detection decisions and detection limits is frequently lost sight of; and that quite erroneous LOD estimates follow from inadequate consideration of the actual variability of the blank, and systematic error associated with the blank, the calibration-recovery factor, matrix effects, and ''black box'' data reduction models

The limit of detection for explosives in spectroscopic differential reflectometry

Science.gov (United States)

Dubroca, Thierry; Vishwanathan, Karthik; Hummel, Rolf E.

2011-05-01

In the wake of recent terrorist attacks, such as the 2008 Mumbai hotel explosion or the December 25th 2009 "underwear bomber", our group has developed a technique (US patent #7368292) to apply differential reflection spectroscopy to detect traces of explosives. Briefly, light (200-500 nm) is shone on a surface such as a piece of luggage at an airport. Upon reflection, the light is collected with a spectrometer combined with a CCD camera. A computer processes the data and produces in turn a differential reflection spectrum involving two adjacent areas of the surface. This differential technique is highly sensitive and provides spectroscopic data of explosives. As an example, 2,4,6, trinitrotoluene (TNT) displays strong and distinct features in differential reflectograms near 420 nm. Similar, but distinctly different features are observed for other explosives. One of the most important criteria for explosive detection techniques is the limit of detection. This limit is defined as the amount of explosive material necessary to produce a signal to noise ratio of three. We present here, a method to evaluate the limit of detection of our technique. Finally, we present our sample preparation method and experimental set-up specifically developed to measure the limit of detection for our technology. This results in a limit ranging from 100 nano-grams to 50 micro-grams depending on the method and the set-up parameters used, such as the detector-sample distance.

Calibrate the aerial surveying instrument by the limited surface source and the single point source that replace the unlimited surface source

International Nuclear Information System (INIS)

Lu Cunheng

1999-01-01

It is described that the calculating formula and surveying result is found on the basis of the stacking principle of gamma ray and the feature of hexagonal surface source when the limited surface source replaces the unlimited surface source to calibrate the aerial survey instrument on the ground, and that it is found in the light of the exchanged principle of the gamma ray when the single point source replaces the unlimited surface source to calibrate aerial surveying instrument in the air. Meanwhile through the theoretical analysis, the receiving rate of the crystal bottom and side surfaces is calculated when aerial surveying instrument receives gamma ray. The mathematical expression of the gamma ray decaying following height according to the Jinge function regularity is got. According to this regularity, the absorbing coefficient that air absorbs the gamma ray and the detective efficiency coefficient of the crystal is calculated based on the ground and air measuring value of the bottom surface receiving count rate (derived from total receiving count rate of the bottom and side surface). Finally, according to the measuring value, it is proved that imitating the change of total receiving gamma ray exposure rate of the bottom and side surfaces with this regularity in a certain high area is feasible

Detection of time-varying harmonic amplitude alterations due to spectral interpolations between musical instrument tones.

Science.gov (United States)

Horner, Andrew B; Beauchamp, James W; So, Richard H Y

2009-01-01

Gradated spectral interpolations between musical instrument tone pairs were used to investigate discrimination as a function of time-averaged spectral difference. All possible nonidentical pairs taken from a collection of eight musical instrument sounds consisting of bassoon, clarinet, flute, horn, oboe, saxophone, trumpet, and violin were tested. For each pair, several tones were generated with different balances between the primary and secondary instruments, where the balance was fixed across the duration of each tone. Among primary instruments it was found that changes to horn and bassoon [corrected] were most easily discriminable, while changes to saxophone and trumpet timbres were least discriminable. Among secondary instruments, the clarinet had the strongest effect on discrimination, whereas the bassoon had the least effect. For primary instruments, strong negative correlations were found between discrimination and their spectral incoherences, suggesting that the presence of dynamic spectral variations tends to increase the difficulty of detecting time-varying alterations such as spectral interpolation.

Detection of colloidal silver chloride near solubility limit

Science.gov (United States)

Putri, K. Y.; Adawiah, R.

2018-03-01

Detection of nanoparticles in solution has been made possible by several means; one of them is laser-induced breakdown detection (LIBD). LIBD is able to distinguish colloids of various sizes and concentrations. This technique has been used in several solubility studies. In this study, the formation of colloids in a mixed system of silver nitrate and sodium chloride was observed by acoustic LIBD. Silver chloride has low solubility limit, therefore LIBD measurement is appropriate. Silver and chloride solutions with equal concentrations, set at below and above the solubility of silver chloride as the expected solid product, were mixed and the resulting colloids were observed. The result of LIBD measurement showed that larger particles were present as more silver and chloride introduced. However, once the concentrations exceeded the solubility limit of silver chloride, the detected particle size seemed to be decreasing, hence suggested the occurrence of coprecipitation process. This phenomenon indicated that the ability of LIBD to detect even small changes in colloid amounts might be a useful tool in study on formation and stability of colloids, i.e. to confirm whether nanoparticles synthesis has been successfully performed and whether the system is stable or not.

Health physics instrument manual

International Nuclear Information System (INIS)

Gupton, E.D.

1978-08-01

The purpose of this manual is to provide apprentice health physics surveyors and other operating groups not directly concerned with radiation detection instruments a working knowledge of the radiation detection and measuring instruments in use at the Laboratory. The characteristics and applications of the instruments are given. Portable instruments, stationary instruments, personnel monitoring instruments, sample counters, and miscellaneous instruments are described. Also, information sheets on calibration sources, procedures, and devices are included. Gamma sources, beta sources, alpha sources, neutron sources, special sources, a gamma calibration device for badge dosimeters, and a calibration device for ionization chambers are described

Recommendations for fluorescence instrument qualification: the new ASTM Standard Guide.

Science.gov (United States)

DeRose, Paul C; Resch-Genger, Ute

2010-03-01

Aimed at improving quality assurance and quantitation for modern fluorescence techniques, ASTM International (ASTM) is about to release a Standard Guide for Fluorescence, reviewed here. The guide's main focus is on steady state fluorometry, for which available standards and instrument characterization procedures are discussed along with their purpose, suitability, and general instructions for use. These include the most relevant instrument properties needing qualification, such as linearity and spectral responsivity of the detection system, spectral irradiance reaching the sample, wavelength accuracy, sensitivity or limit of detection for an analyte, and day-to-day performance verification. With proper consideration of method-inherent requirements and limitations, many of these procedures and standards can be adapted to other fluorescence techniques. In addition, procedures for the determination of other relevant fluorometric quantities including fluorescence quantum yields and fluorescence lifetimes are briefly introduced. The guide is a clear and concise reference geared for users of fluorescence instrumentation at all levels of experience and is intended to aid in the ongoing standardization of fluorescence measurements.

Sulfur dioxide emissions from Peruvian copper smelters detected by the ozone monitoring instrument

NARCIS (Netherlands)

Carn, S.A.; Krueger, A.J.; Krotkov, N.A.; Yang, Kai; Levelt, P.F.

2007-01-01

We report the first daily observations of sulfur dioxide (SO2) emissions from copper smelters by a satellite-borne sensor - the Ozone Monitoring Instrument (OMI) on NASA's EOS/Aura spacecraft. Emissions from two Peruvian smelters (La Oroya and Ilo) were detected in up to 80% of OMI overpasses

Impact of sensor detection limits on protecting water distribution systems from contamination events

International Nuclear Information System (INIS)

McKenna, Sean Andrew; Hart, David Blaine; Yarrington, Lane

2006-01-01

Real-time water quality sensors are becoming commonplace in water distribution systems. However, field deployable, contaminant-specific sensors are still in the development stage. As development proceeds, the necessary operating parameters of these sensors must be determined to protect consumers from accidental and malevolent contamination events. This objective can be quantified in several different ways including minimization of: the time necessary to detect a contamination event, the population exposed to contaminated water, the extent of the contamination within the network, and others. We examine the ability of a sensor set to meet these objectives as a function of both the detection limit of the sensors and the number of sensors in the network. A moderately sized distribution network is used as an example and different sized sets of randomly placed sensors are considered. For each combination of a certain number of sensors and a detection limit, the mean values of the different objectives across multiple random sensor placements are calculated. The tradeoff between the necessary detection limit in a sensor and the number of sensors is evaluated. Results show that for the example problem examined here, a sensor detection limit of 0.01 of the average source concentration is adequate for maximum protection. Detection of events is dependent on the detection limit of the sensors, but for those events that are detected, the values of the performance measures are not a function of the sensor detection limit. The results of replacing a single sensor in a network with a sensor having a much lower detection limit show that while this replacement can improve results, the majority of the additional events detected had performance measures of relatively low consequence.

Censoring approach to the detection limits in X-ray fluorescence analysis

International Nuclear Information System (INIS)

Pajek, M.; Kubala-Kukus, A.

2004-01-01

We demonstrate that the effect of detection limits in the X-ray fluorescence analysis (XRF), which limits the determination of very low concentrations of trace elements and results in appearance of the so-called 'nondetects', can be accounted for using the statistical concept of censoring. More precisely, the results of such measurements can be viewed as the left random censored data, which can further be analyzed using the Kaplan-Meier method correcting the data for the presence of nondetects. Using this approach, the results of measured, detection limit censored concentrations can be interpreted in a nonparametric manner including the correction for the nondetects, i.e. the measurements in which the concentrations were found to be below the actual detection limits. Moreover, using the Monte Carlo simulation technique we show that by using the Kaplan-Meier approach the corrected mean concentrations for a population of the samples can be estimated within a few percent uncertainties with respect of the simulated, uncensored data. This practically means that the final uncertainties of estimated mean values are limited in fact by the number of studied samples and not by the correction procedure itself. The discussed random-left censoring approach was applied to analyze the XRF detection-limit-censored concentration measurements of trace elements in biomedical samples

Fuzzy associative memories for instrument fault detection

International Nuclear Information System (INIS)

Heger, A.S.

1996-01-01

A fuzzy logic instrument fault detection scheme is developed for systems having two or three redundant sensors. In the fuzzy logic approach the deviation between each signal pairing is computed and classified into three fuzzy sets. A rule base is created allowing the human perception of the situation to be represented mathematically. Fuzzy associative memories are then applied. Finally, a defuzzification scheme is used to find the centroid location, and hence the signal status. Real-time analyses are carried out to evaluate the instantaneous signal status as well as the long-term results for the sensor set. Instantaneous signal validation results are used to compute a best estimate for the measured state variable. The long-term sensor validation method uses a frequency fuzzy variable to determine the signal condition over a specific period. To corroborate the methodology synthetic data representing various anomalies are analyzed with both the fuzzy logic technique and the parity space approach. (Author)

Instrumentation Cables Test Plan

Energy Technology Data Exchange (ETDEWEB)

Muna, Alice Baca [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); LaFleur, Chris Bensdotter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-10-01

A fire at a nuclear power plant (NPP) has the potential to damage structures, systems, and components important to safety, if not promptly detected and suppressed. At Browns Ferry Nuclear Power Plant on March 22, 1975, a fire in the reactor building damaged electrical power and control systems. Damage to instrumentation cables impeded the function of both normal and standby reactor coolant systems, and degraded the operators’ plant monitoring capability. This event resulted in additional NRC involvement with utilities to ensure that NPPs are properly protected from fire as intended by the NRC principle design criteria (i.e., general design criteria 3, Fire Protection). Current guidance and methods for both deterministic and performance based approaches typically make conservative (bounding) assumptions regarding the fire-induced failure modes of instrumentation cables and those failure modes effects on component and system response. Numerous fire testing programs have been conducted in the past to evaluate the failure modes and effects of electrical cables exposed to severe thermal conditions. However, that testing has primarily focused on control circuits with only a limited number of tests performed on instrumentation circuits. In 2001, the Nuclear Energy Institute (NEI) and the Electric Power Research Institute (EPRI) conducted a series of cable fire tests designed to address specific aspects of the cable failure and circuit fault issues of concern1. The NRC was invited to observe and participate in that program. The NRC sponsored Sandia National Laboratories to support this participation, whom among other things, added a 4-20 mA instrumentation circuit and instrumentation cabling to six of the tests. Although limited, one insight drawn from those instrumentation circuits tests was that the failure characteristics appeared to depend on the cable insulation material. The results showed that for thermoset insulated cables, the instrument reading tended to drift

Importance of the lower limit of detection in radiological safety; Importancia del limite inferior de deteccion en seguridad radiologica

Energy Technology Data Exchange (ETDEWEB)

Rafael, Terol T; Hermenegildo, Maldonado M [Comision Nacional de Seguridad Nuclear y Salvaguardias (Mexico)

1991-07-01

The concept of the Lower Limit of Detection (LLD) it contributes in the solution of some problems related with the radiological safety, such as the realization of the tests of flight of the sealed radioactive sources; the determination of radioisotopes in environmental samples; the estimate of present radionuclides in polluted foods; in general, the detection of small quantities of radioactive materials present in materials of use or consumption by part of the man in his daily life; as the one Lower Limit of Detection is related with topics of statistics, in this work a small review of them is made, it was superficially discussed the mensuration problems related with the establishment of the Lower Limit of Detection.

Detection limits of nuclear radiation and radioactivity measurements. Digital, non-selective measurements on untreated specimens. Draft. Nachweisgrenzen bei Kernstrahlungs- und Radioaktivitaetsmessungen. Digitale, nichtselektive Messungen ohne Probenbehandlung. Entwurf

Energy Technology Data Exchange (ETDEWEB)

1985-01-01

The standard applies to nuclear radiation measurements where the number of pulses is recorded directly, considering exclusively the statistical character of radioactive decay and pulse counting, with the measuring time being short with regard to the half-life of radionuclides, and instrument dead-times being neglectible. The standard is intended to define suitable characteristics allowing an evaluation of detection efficiency. Two criteria are explained for given error probabilities: the sensitivity limit which allows a decision to be made as to whether the pulses recorded include values contributed by the sample; the detection limit which permits an evaluation of the measuring method in terms of suitability to the measuring goals. (orig./HP).

Compendium of Instrumentation Whitepapers on Frontier Physics Needs for Snowmass 2013

Energy Technology Data Exchange (ETDEWEB)

Lipton, R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

2013-01-01

Contents of collection of whitepapers include: Operation of Collider Experiments at High Luminosity; Level 1 Track Triggers at HL-LHC; Tracking and Vertex Detectors for a Muon Collider; Triggers for hadron colliders at the energy frontier; ATLAS Upgrade Instrumentation; Instrumentation for the Energy Frontier; Particle Flow Calorimetry for CMS; Noble Liquid Calorimeters; Hadronic dual-readout calorimetry for high energy colliders; Another Detector for the International Linear Collider; e+e- Linear Colliders Detector Requirements and Limitations; Electromagnetic Calorimetry in Project X Experiments The Project X Physics Study; Intensity Frontier Instrumentation; Project X Physics Study Calorimetry Report; Project X Physics Study Tracking Report; The LHCb Upgrade; Neutrino Detectors Working Group Summary; Advanced Water Cherenkov R&D for WATCHMAN; Liquid Argon Time Projection Chamber (LArTPC); Liquid Scintillator Instrumentation for Physics Frontiers; A readout architecture for 100,000 pixel Microwave Kinetic In- ductance Detector array; Instrumentation for New Measurements of the Cosmic Microwave Background polarization; Future Atmospheric and Water Cherenkov ?-ray Detectors; Dark Energy; Can Columnar Recombination Provide Directional Sensitivity in WIMP Search?; Instrumentation Needs for Detection of Ultra-high Energy Neu- trinos; Low Background Materials for Direct Detection of Dark Matter; Physics Motivation for WIMP Dark Matter Directional Detection; Solid Xenon R&D at Fermilab; Ultra High Energy Neutrinos; Instrumentation Frontier: Direct Detection of WIMPs; nEXO detector R&D; Large Arrays of Air Cherenkov Detectors; and Applications of Laser Interferometry in Fundamental Physics Experiments.

Instrumental parameters' determination in a fluorescences X-ray Philips PW 1400 equipment

International Nuclear Information System (INIS)

Martinez, J.M.; Fasio, I.; Baronio, N.; Viola, M.

1987-01-01

The instrumental parameters of a Philips PW 1400 equipment wavelengths dispersive are determined; fundamentally, those related to the equipment's accuracy (stability at a very short, short and long term drift) as well as to those related to the detection system (dead time, detector's cleaning and detection limit). (S.M.) [es

Detection of gamma-ray bursts with the ECLAIRs instrument onboard the space mission SVOM

International Nuclear Information System (INIS)

Antier-Farfar, Sarah

2016-01-01

Discovered in the early 1970's, gamma-ray bursts (GRBs) are amazing cosmic phenomena appearing randomly on the sky and releasing large amounts of energy mainly through gamma-ray emission. Although their origin is still under debate, they are believed to be produced by some of the most violent explosions in the Universe leading to the formation of stellar black-holes. GRBs are detected by their prompt emission, an intense short burst of gamma-rays (from a few milliseconds to few minutes), and are followed by a lived-afterglow emission observed on longer timescales from the X-ray to the radio domain. My thesis participates to the development of the SVOM mission, which a Chinese-French mission to be launched in 2021, devoted to the study of GRBs and involving space and ground instruments. My work is focussed on the main instrument ECLAIRs, a hard X-ray coded mask imaging camera, in charge of the near real-time detection and localization of the prompt emission of GRBs. During my thesis, I studied the scientific performances of ECLAIRs and in particular the number of GRBs expected to be detected by ECLAIRs and their characteristics. For this purpose, I performed simulations using the prototypes of the embedded trigger algorithms combined with the model of the ECLAIRs instrument. The input data of the simulations include a background model and a synthetic population of gamma-ray bursts generated from existing catalogs (CGRO, HETE-2, Fermi and Swift). As a result, I estimated precisely the ECLAIRs detection efficiency of the algorithms and I predicted the number of GRBs to be detected by ECLAIRs: 40 to 70 GRBs per year. Moreover, the study highlighted that ECLAIRs will be particularly sensitive to the X-ray rich GRB population. My thesis provided additional studies about the localization performance, the rate of false alarm and the characteristics of the triggers of the algorithms. Finally, I also proposed two new methods for the detection of GRBs.The preliminary

Detection limits of antimicrobials in ewe milk by delvotest photometric measurements.

Science.gov (United States)

Althaus, R L; Torres, A; Montero, A; Balasch, S; Molina, M P

2003-02-01

The Delvotest method detection limits per manufacturer's instructions at a fixed reading time of 3 h for 24 antimicrobial agents were determined in ewe milk by photometric measurement. For each drug, eight concentrations were tested on 20 ewe milk samples from individual ewes. Detection limits, determined by means of logistic regression models, were (microg/kg): 3, amoxycillin; 2, ampicillin; 18, cloxacillin; 1, penicillin "G"; 34, cefadroxil; 430, cephalosporin "C"; 40, cephalexin; 20, cefoperazone; 33, Ceftiofur; 18, cefuroxime; 6100, streptomycin; 1200, gentamycin; 2600, neomycin; 830, erythromycin; 100, tylosin; 180, doxycycline; 320, oxytetracycline; 590, tetracycline; 88, sulfadiazine; 44, sulfamethoxazole; 140, sulfametoxypyridazine; 48, sulfaquinoxaline; 12,000, chloramphenicol; and 290, trimethoprim. Whereas the beta-lactam antibiotics, sulphonamides, and tylosin were detected by Delvotest method at levels equal to those of maximum residue limits, its sensitivity needs to be enhanced to detect aminoglycosides, tetracyclines, streptomycin, chloramphenicol, and trimethoprim residues in ewe milk or to develop an integrated residue detection system for ewe milk with different sensitive microorganisms for each group of antiinfectious agents.

The Use and Abuse of Limits of Detection in Environmental Analytical Chemistry

Directory of Open Access Journals (Sweden)

Richard J. C. Brown

2008-01-01

Full Text Available The limit of detection (LoD serves as an important method performance measure that is useful for the comparison of measurement techniques and the assessment of likely signal to noise performance, especially in environmental analytical chemistry. However, the LoD is only truly related to the precision characteristics of the analytical instrument employed for the analysis and the content of analyte in the blank sample. This article discusses how other criteria, such as sampling volume, can serve to distort the quoted LoD artificially and make comparison between various analytical methods inequitable. In order to compare LoDs between methods properly, it is necessary to state clearly all of the input parameters relating to the measurements that have been used in the calculation of the LoD. Additionally, the article discusses that the use of LoDs in contexts other than the comparison of the attributes of analytical methods, in particular when reporting analytical results, may be confusing, less informative than quoting the actual result with an accompanying statement of uncertainty, and may act to bias descriptive statistics.

Limiter discriminator detection of M-ary FSK signals

Science.gov (United States)

Fonseka, John P.

1990-10-01

The performance of limiter discriminator detection of M-ary FSK signals is analyzed at arbitrary modulation indices. It is shown that the error rate performance of limiter discriminator detection can be significantly improved by increasing the modulation index above 1/M. The optimum modulation index that minimizes the overall error probability is determined for the cases M = 2, 4 and 8. The analysis is carried out for wideband and bandlimited channels with Gaussian and second-order Butterworth filters. It is shown that the optimum modulation index depends on the signal/noise ratio (SNR), in a wideband channel, and on both SNR and time-bandwidth product in a bandlimited channel. Finally, it is shown that the optimum sampling instance in presence of a nonzero phase IF filter can be approximately determined by using only the worst case symbol pattern.

Realistic limitations of detecting planets around young active stars

Directory of Open Access Journals (Sweden)

Pinfield D.

2013-04-01

Full Text Available Current planet hunting methods using the radial velocity method are limited to observing middle-aged main-sequence stars where the signatures of stellar activity are much less than on young stars that have just arrived on the main-sequence. In this work we apply our knowledge from the surface imaging of these young stars to place realistic limitations on the possibility of detecting orbiting planets. In general we find that the magnitude of the stellar jitter is directly proportional to the stellar vsini. For G and K dwarfs, we find that it is possible, for models with high stellar activity and low stellar vsini, to be able to detect a 1 MJupiter mass planet within 50 epochs of observations and for the M dwarfs it is possible to detect a habitable zone Earth-like planet in 10s of observational epochs.

Minimum detectable activities of contamination control survey equipment

International Nuclear Information System (INIS)

Goles, R.W.; Baumann, B.L.; Johnson, M.L.

1991-08-01

The Instrumentation ampersand External Dosimetry (I ampersand ED) Section of the Health Physics Department at the Pacific Northwest Laboratory (PNL) has performed a series of tests to determine the ability of portable survey instruments used at Hanford to detect radioactive contamination at levels required by DOE 5480.11. This semi-empirical study combines instrumental, statistical, and human factors as necessary to derive operational detection limits. These threshold detection values have been compared to existing contamination control requirements, and detection deficiencies have been identified when present. Portable survey instruments used on the Hanford Site identify the presence of radioactive surface contamination based on the detection of α-, β-, γ-, and/or x-radiation. However, except in some unique circumstances, most contamination monitors in use at Hanford are configured to detect either α-radiation alone or β- and γ-radiation together. Testing was therefore conducted on only these two categories of radiation detection devices. Nevertheless, many of the results obtained are generally applicable to all survey instruments, allowing performance evaluations to be extended to monitoring devices which are exclusively γ- and/or x-ray- sensitive. 6 figs., 2 tabs

A damage detection method for instrumented civil structures using prerecorded Green’s functions and cross-correlation

OpenAIRE

Heckman, Vanessa; Kohler, Monica; Heaton, Thomas

2011-01-01

Automated damage detection methods have application to instrumented structures that are susceptible to types of damage that are difficult or costly to detect. The presented method has application to the detection of brittle fracture of welded beam-column connections in steel moment-resisting frames (MRFs), where locations of potential structural damage are known a priori. The method makes use of a prerecorded catalog of Green’s function templates and a cross-correlation method ...

Algorithms for a hand-held miniature x-ray fluorescence analytical instrument

International Nuclear Information System (INIS)

Elam, W.T.; Newman, D.; Ziemba, F.

1998-01-01

The purpose of this joint program was to provide technical assistance with the development of a Miniature X-ray Fluorescence (XRF) Analytical Instrument. This new XRF instrument is designed to overcome the weaknesses of spectrometers commercially available at the present time. Currently available XRF spectrometers (for a complete list see reference 1) convert spectral information to sample composition using the influence coefficients technique or the fundamental parameters method. They require either a standard sample with composition relatively close to the unknown or a detailed knowledge of the sample matrix. They also require a highly-trained operator and the results often depend on the capabilities of the operator. In addition, almost all existing field-portable, hand-held instruments use radioactive sources for excitation. Regulatory limits on such sources restrict them such that they can only provide relatively weak excitation. This limits all current hand-held XRF instruments to poor detection limits and/or long data collection times, in addition to the licensing requirements and disposal problems for radioactive sources. The new XRF instrument was developed jointly by Quantrad Sensor, Inc., the Naval Research Laboratory (NRL), and the Department of Energy (DOE). This report describes the analysis algorithms developed by NRL for the new instrument and the software which embodies them

Which Instruments can Detect Submaximal Physical and Functional Capacity in Patients With Chronic Nonspecific Back Pain?: A Systematic Review

NARCIS (Netherlands)

van der Meer, Suzan; Trippolini, Maurizio A.; van der Palen, Jacobus Adrianus Maria; Verhoeven, Jan; Reneman, Michiel F.

2013-01-01

Objective. To evaluate the validity of instruments that claim to detect submaximal capacity when maximal capacity is requested in patients with chronic nonspecific musculoskeletal pain. Summary of Background Data. Several instruments have been developed to measure capacity in patients with chronic

Which Instruments Can Detect Submaximal Physical and Functional Capacity in Patients With Chronic Nonspecific Back Pain? A Systematic Review

NARCIS (Netherlands)

van der Meer, Suzan; Trippolini, Maurizio A.; van der Palen, Job; Verhoeven, Jan; Reneman, Michiel F.

2013-01-01

Study Design. Systematic review. Objective. To evaluate the validity of instruments that claim to detect submaximal capacity when maximal capacity is requested in patients with chronic nonspecific musculoskeletal pain. Summary of Background Data. Several instruments have been developed to measure

A Portable Array-Type Optical Fiber Sensing Instrument for Real-Time Gas Detection

Directory of Open Access Journals (Sweden)

San-Shan Hung

2016-12-01

Full Text Available A novel optical fiber array-type of sensing instrument with temperature compensation for real-time detection was developed to measure oxygen, carbon dioxide, and ammonia simultaneously. The proposed instrument is multi-sensing array integrated with real-time measurement module for portable applications. The sensing optical fibers were etched and polished before coating to increase sensitivities. The ammonia and temperature sensors were each composed of a dye-coated single-mode fiber with constructing a fiber Bragg grating and a long-period filter grating for detecting light intensity. Both carbon dioxide and oxygen sensing structures use multimode fibers where 1-hydroxy-3,6,8-pyrene trisulfonic acid trisodium salt is coated for carbon dioxide sensing and Tris(2,2′-bipyridyl dichlororuthenium(II hexahydrate and Tris(bipyridineruthenium(II chloride are coated for oxygen sensing. Gas-induced fluorescent light intensity variation was applied to detect gas concentration. The portable gas sensing array was set up by integrating with photo-electronic measurement modules and a human-machine interface to detect gases in real time. The measured data have been processed using piecewise-linear method. The sensitivity of the oxygen sensor were 1.54%/V and 9.62%/V for concentrations less than 1.5% and for concentrations between 1.5% and 6%, respectively. The sensitivity of the carbon dioxide sensor were 8.33%/V and 9.62%/V for concentrations less than 2% and for concentrations between 2% and 5%, respectively. For the ammonia sensor, the sensitivity was 27.78%/V, while ammonia concentration was less than 2%.

A Portable Array-Type Optical Fiber Sensing Instrument for Real-Time Gas Detection.

Science.gov (United States)

Hung, San-Shan; Chang, Hsing-Cheng; Chang, I-Nan

2016-12-08

A novel optical fiber array-type of sensing instrument with temperature compensation for real-time detection was developed to measure oxygen, carbon dioxide, and ammonia simultaneously. The proposed instrument is multi-sensing array integrated with real-time measurement module for portable applications. The sensing optical fibers were etched and polished before coating to increase sensitivities. The ammonia and temperature sensors were each composed of a dye-coated single-mode fiber with constructing a fiber Bragg grating and a long-period filter grating for detecting light intensity. Both carbon dioxide and oxygen sensing structures use multimode fibers where 1-hydroxy-3,6,8-pyrene trisulfonic acid trisodium salt is coated for carbon dioxide sensing and Tris(2,2'-bipyridyl) dichlororuthenium(II) hexahydrate and Tris(bipyridine)ruthenium(II) chloride are coated for oxygen sensing. Gas-induced fluorescent light intensity variation was applied to detect gas concentration. The portable gas sensing array was set up by integrating with photo-electronic measurement modules and a human-machine interface to detect gases in real time. The measured data have been processed using piecewise-linear method. The sensitivity of the oxygen sensor were 1.54%/V and 9.62%/V for concentrations less than 1.5% and for concentrations between 1.5% and 6%, respectively. The sensitivity of the carbon dioxide sensor were 8.33%/V and 9.62%/V for concentrations less than 2% and for concentrations between 2% and 5%, respectively. For the ammonia sensor, the sensitivity was 27.78%/V, while ammonia concentration was less than 2%.

Correction to the count-rate detection limit and sample/blank time-allocation methods

International Nuclear Information System (INIS)

Alvarez, Joseph L.

2013-01-01

A common form of count-rate detection limits contains a propagation of uncertainty error. This error originated in methods to minimize uncertainty in the subtraction of the blank counts from the gross sample counts by allocation of blank and sample counting times. Correct uncertainty propagation showed that the time allocation equations have no solution. This publication presents the correct form of count-rate detection limits. -- Highlights: •The paper demonstrated a proper method of propagating uncertainty of count rate differences. •The standard count-rate detection limits were in error. •Count-time allocation methods for minimum uncertainty were in error. •The paper presented the correct form of the count-rate detection limit. •The paper discussed the confusion between count-rate uncertainty and count uncertainty

Astrobiology Sample Analysis Program (ASAP) for Advanced Life Detection Instrumentation Development and Calibration

Science.gov (United States)

Glavin, Daniel; Brinkerhoff, Will; Dworkin, Jason; Eigenbrode, Jennifer; Franz, Heather; Mahaffy, Paul; Stern, Jen; Blake, Daid; Sandford, Scott; Fries, marc;

Improving global detection of volcanic eruptions using the Ozone Monitoring Instrument (OMI

Directory of Open Access Journals (Sweden)

V. J. B. Flower

2016-11-01

Full Text Available Volcanic eruptions pose an ever-present threat to human populations around the globe, but many active volcanoes remain poorly monitored. In regions where ground-based monitoring is present the effects of volcanic eruptions can be moderated through observational alerts to both local populations and service providers, such as air traffic control. However, in regions where volcano monitoring is limited satellite-based remote sensing provides a global data source that can be utilised to provide near-real-time identification of volcanic activity. This paper details a volcanic plume detection method capable of identifying smaller eruptions than is currently feasible, which could potentially be incorporated into automated volcanic alert systems. This method utilises daily, global observations of sulfur dioxide (SO2 by the Ozone Monitoring Instrument (OMI on NASA's Aura satellite. Following identification and classification of known volcanic eruptions in 2005–2009, the OMI SO2 data, analysed using a logistic regression analysis, permitted the correct classification of volcanic events with an overall accuracy of over 80 %. Accurate volcanic plume identification was possible when lower-tropospheric SO2 loading exceeded ∼ 400 t. The accuracy and minimal user input requirements of the developed procedure provide a basis for incorporation into automated SO2 alert systems.

Theoretical detection limit of PIXE analysis using 20 MeV proton beams

Science.gov (United States)

Ishii, Keizo; Hitomi, Keitaro

2018-02-01

Particle-induced X-ray emission (PIXE) analysis is usually performed using proton beams with energies in the range 2∼3 MeV because at these energies, the detection limit is low. The detection limit of PIXE analysis depends on the X-ray production cross-section, the continuous background of the PIXE spectrum and the experimental parameters such as the beam currents and the solid angle and detector efficiency of X-ray detector. Though the continuous background increases as the projectile energy increases, the cross-section of the X-ray increases as well. Therefore, the detection limit of high energy proton PIXE is not expected to increase significantly. We calculated the cross sections of continuous X-rays produced in several bremsstrahlung processes and estimated the detection limit of a 20 MeV proton PIXE analysis by modelling the Compton tail of the γ-rays produced in the nuclear reactions, and the escape effect on the secondary electron bremsstrahlung. We found that the Compton tail does not affect the detection limit when a thin X-ray detector is used, but the secondary electron bremsstrahlung escape effect does have an impact. We also confirmed that the detection limit of the PIXE analysis, when used with 4 μm polyethylene backing film and an integrated beam current of 1 μC, is 0.4∼2.0 ppm for proton energies in the range 10∼30 MeV and elements with Z = 16-90. This result demonstrates the usefulness of several 10 MeV cyclotrons for performing PIXE analysis. Cyclotrons with these properties are currently installed in positron emission tomography (PET) centers.

Correlation or Limits of Agreement? Applying the Bland-Altman Approach to the Comparison of Cognitive Screening Instruments.

Science.gov (United States)

Larner, A J

2016-01-01

Calculation of correlation coefficients is often undertaken as a way of comparing different cognitive screening instruments (CSIs). However, test scores may correlate but not agree, and high correlation may mask lack of agreement between scores. The aim of this study was to use the methodology of Bland and Altman to calculate limits of agreement between the scores of selected CSIs and contrast the findings with Pearson's product moment correlation coefficients between the test scores of the same instruments. Datasets from three pragmatic diagnostic accuracy studies which examined the Mini-Mental State Examination (MMSE) vs. the Montreal Cognitive Assessment (MoCA), the MMSE vs. the Mini-Addenbrooke's Cognitive Examination (M-ACE), and the M-ACE vs. the MoCA were analysed to calculate correlation coefficients and limits of agreement between test scores. Although test scores were highly correlated (all >0.8), calculated limits of agreement were broad (all >10 points), and in one case, MMSE vs. M-ACE, was >15 points. Correlation is not agreement. Highly correlated test scores may conceal broad limits of agreement, consistent with the different emphases of different tests with respect to the cognitive domains examined. Routine incorporation of limits of agreement into diagnostic accuracy studies which compare different tests merits consideration, to enable clinicians to judge whether or not their agreement is close. © 2016 S. Karger AG, Basel.

Limited Streamer Tubes for the BaBar Instrumented Flux Return Upgrade

International Nuclear Information System (INIS)

Lu, C.

2005-01-01

Starting from the very beginning of their operation the efficiency of the RPC chambers in the BaBar Instrumented Flux Return (IFR) has suffered serious degradation. After intensive investigation, various remediation efforts had been carried out, but without success. As a result the BaBar collaboration decided to replace the dying barrel RPC chambers about two years ago. To study the feasibility of using the Limited Streamer Tube (LST) as the replacement of RPC we carried out an R and D program that has resulted in BaBar's deciding to replace the barrel RPC's with LST's. In this report we summarize the major detector R and D results, and leave other issues of the IFR system upgrade to the future publications

Censoring: a new approach for detection limits in total-reflection X-ray fluorescence

International Nuclear Information System (INIS)

Pajek, M.; Kubala-Kukus, A.; Braziewicz, J.

2004-01-01

It is shown that the detection limits in the total-reflection X-ray fluorescence (TXRF), which restrict quantification of very low concentrations of trace elements in the samples, can be accounted for using the statistical concept of censoring. We demonstrate that the incomplete TXRF measurements containing the so-called 'nondetects', i.e. the non-measured concentrations falling below the detection limits and represented by the estimated detection limit values, can be viewed as the left random-censored data, which can be further analyzed using the Kaplan-Meier (KM) method correcting for nondetects. Within this approach, which uses the Kaplan-Meier product-limit estimator to obtain the cumulative distribution function corrected for the nondetects, the mean value and median of the detection limit censored concentrations can be estimated in a non-parametric way. The Monte Carlo simulations performed show that the Kaplan-Meier approach yields highly accurate estimates for the mean and median concentrations, being within a few percent with respect to the simulated, uncensored data. This means that the uncertainties of KM estimated mean value and median are limited in fact only by the number of studied samples and not by the applied correction procedure for nondetects itself. On the other hand, it is observed that, in case when the concentration of a given element is not measured in all the samples, simple approaches to estimate a mean concentration value from the data yield erroneous, systematically biased results. The discussed random-left censoring approach was applied to analyze the TXRF detection-limit-censored concentration measurements of trace elements in biomedical samples. We emphasize that the Kaplan-Meier approach allows one to estimate the mean concentrations being substantially below the mean level of detection limits. Consequently, this approach gives a new access to lower the effective detection limits for TXRF method, which is of prime interest for

Near instrument-free, simple molecular device for rapid detection of herpes simplex viruses.

Science.gov (United States)

Lemieux, Bertrand; Li, Ying; Kong, Huimin; Tang, Yi-Wei

2012-06-01

The first near instrument-free, inexpensive and simple molecular diagnostic device (IsoAmp HSV, BioHelix Corp., MA, USA) recently received US FDA clearance for use in the detection of herpes simplex viruses (HSV) in genital and oral lesion specimens. The IsoAmp HSV assay uses isothermal helicase-dependent amplification in combination with a disposable, hermetically-sealed, vertical-flow strip identification. The IsoAmp HSV assay has a total test-to-result time of less than 1.5 h by omitting the time-consuming nucleic acid extraction. The diagnostic sensitivity and specificity are comparable to PCR and are superior to culture-based methods. The near instrument-free, rapid and simple characteristics of the IsoAmp HSV assay make it potentially suitable for point-of-care testing.

Evaluation of MidIR fibre optic reflectance: Detection limit, reproducibility and binary mixture discrimination

Science.gov (United States)

Sessa, Clarimma; Bagán, Héctor; García, José Francisco

2013-11-01

MidIR fibre optic reflectance (MidIR-FORS) is a promising analytical technique in the field of science conservation, especially because it is non-destructive. Another advantage of MidIR-FORS is that the obtained information is representative, as a large amount of spectral data can be collected. Although the technique has a high potential and is almost routinely applied, its quality parameters have not been thoroughly studied in the specific application of analysis of artistic materials. The objective of this study is to evaluate the instrumental capabilities of MidIR-FORS for the analysis of artwork materials in terms of detection limit, reproducibility, and mixture characterisation. The study has been focused on oil easel painting and several paints of known composition have been analysed. Paint layers include blue pigments not only because of their important role along art history, but also because their physical and spectroscopic characteristics allow a better evaluation of the MidIR-FORS capabilities. The results of the analysis indicate that MidIR-FORS supplies a signal affected by different factors, such as the optical, morphological and physical properties of the surface, in addition to the composition of materials analysed. Consequently, the detection limits established are relatively high for artistic objects (Prussian blue - PB 2.1-6.5%; Phthalocyanine blue - Pht 6.3-10.2%; synthetic Ultramarine blue - UM 12.1%) and may therefore lead to an incomplete description of the artwork. Reproducibility of the technique over time and across surface has been determined. The results show that the major sources of dispersion are the heterogeneity of the pigments distribution, physical features, and band shape distortions. The total dispersion is around 4% for the most intense bands (oil) and increases up to 26% when weak or overlapped bands are considered (PB, Pht, UM). The application of different pre-treatments (cutoff of fibres absorption, Savizky-Golay smoothing

Instrument for Real-Time Digital Nucleic Acid Amplification on Custom Microfluidic Devices.

Directory of Open Access Journals (Sweden)

David A Selck

Full Text Available Nucleic acid amplification tests that are coupled with a digital readout enable the absolute quantification of single molecules, even at ultralow concentrations. Digital methods are robust, versatile and compatible with many amplification chemistries including isothermal amplification, making them particularly invaluable to assays that require sensitive detection, such as the quantification of viral load in occult infections or detection of sparse amounts of DNA from forensic samples. A number of microfluidic platforms are being developed for carrying out digital amplification. However, the mechanistic investigation and optimization of digital assays has been limited by the lack of real-time kinetic information about which factors affect the digital efficiency and analytical sensitivity of a reaction. Commercially available instruments that are capable of tracking digital reactions in real-time are restricted to only a small number of device types and sample-preparation strategies. Thus, most researchers who wish to develop, study, or optimize digital assays rely on the rate of the amplification reaction when performed in a bulk experiment, which is now recognized as an unreliable predictor of digital efficiency. To expand our ability to study how digital reactions proceed in real-time and enable us to optimize both the digital efficiency and analytical sensitivity of digital assays, we built a custom large-format digital real-time amplification instrument that can accommodate a wide variety of devices, amplification chemistries and sample-handling conditions. Herein, we validate this instrument, we provide detailed schematics that will enable others to build their own custom instruments, and we include a complete custom software suite to collect and analyze the data retrieved from the instrument. We believe assay optimizations enabled by this instrument will improve the current limits of nucleic acid detection and quantification, improving our

TFTR movable limiter instrumentation and controls

International Nuclear Information System (INIS)

Frankenberg, J.; Collins, D.; Kaufmann, D.; Mamoun, A.

1983-01-01

The TFTR movable limiter is a single poloidal limiter located within one 18 /SUP o/ segment of the vacuum vessel. It consists of three (3) interconnected inconel backing plates covered with titanium carbide coated graphite tiles. The backing plates are positioned by three independent screw drive actuators. Cooling water is fed through the horizontal port cover to tubes brazed onto the backs of the backing plates. Thermocouples monitor the limiter temperature. (1) and more fully described in refs. (1) and (2). The positioning actuators are driven by independently controlled DC servo motors, controlled either locally or from CICADA. Drive motor shaft position is monitored by chain driven encoders and potentiometers. Limiter blade position can be varied to suit any plasma within the operating range. CICADA is programmed to keep the limiter stroke within safe operating limits. A microprocessor duplicates the CICADA protective function allowing limiter operation without CICADA. The potentiometer signal is sent to an analog computer, which safeguards the limiter against failure of the encoders or the micro-processor. Cooling water flows through the limiter in 3 separate paths, one for each blade. The flow rate and temperature rise through each loop are measured accurately to allow CICADA to calculate the heat into each blade. The water system is also interlocked and alarmed to prevent dumping of water into the vacuum vessel

NESSI and `Alopeke: Two new dual-channel speckle imaging instruments

Science.gov (United States)

Scott, Nicholas J.

2018-01-01

NESSI and `Alopeke are two new speckle imagers built at NASA's Ames Research Center for community use at the WIYN and Gemini telescopes, respectively. The two instruments are functionally similar and include the capability for wide-field imaging in additional to speckle interferometry. The diffraction-limited imaging available through speckle effectively eliminates distortions due to the presence of Earth's atmosphere by `freezing out' changes in the atmosphere by taking extremely short exposures and combining the resultant speckles in Fourier space. This technique enables angular resolutions equal to the theoretical best possible for a given telescope, effectively giving space-based resolution from the ground. Our instruments provide the highest spatial resolution available today on any single aperture telescope.A primary role of these instruments is exoplanet validation for the Kepler, K2, TESS, and many RV programs. Contrast ratios of 6 or more magnitudes are easily obtained. The instrument uses two emCCD cameras providing simultaneous dual-color observations help to characterize detected companions. High resolution imaging enables the identification of blended binaries that contaminate many exoplanet detections, leading to incorrectly measured radii. In this way small, rocky systems, such as Kepler-186b and the TRAPPIST-1 planet family, may be validated and thus the detected planets radii are correctly measured.

Modelling and interpretation of gas detection using remote laser pointers.

Science.gov (United States)

Hodgkinson, J; van Well, B; Padgett, M; Pride, R D

2006-04-01

We have developed a quantitative model of the performance of laser pointer style gas leak detectors, which are based on remote detection of backscattered radiation. The model incorporates instrumental noise limits, the reflectivity of the target background surface and a mathematical description of gas leak dispersion in constant wind speed and turbulence conditions. We have investigated optimum instrument performance and limits of detection in simulated leak detection situations. We predict that the optimum height for instruments is at eye level or above, giving an operating range of 10 m or more for most background surfaces, in wind speeds of up to 2.5 ms(-1). For ground based leak sources, we find laser pointer measurements are dominated by gas concentrations over a short distance close to the target surface, making their readings intuitive to end users in most cases. This finding is consistent with the results of field trials.

Accuracy, precision, and lower detection limits (a deficit reduction approach)

International Nuclear Information System (INIS)

Bishop, C.T.

1993-01-01

The evaluation of the accuracy, precision and lower detection limits of the determination of trace radionuclides in environmental samples can become quite sophisticated and time consuming. This in turn could add significant cost to the analyses being performed. In the present method, a open-quotes deficit reduction approachclose quotes has been taken to keep costs low, but at the same time provide defensible data. In order to measure the accuracy of a particular method, reference samples are measured over the time period that the actual samples are being analyzed. Using a Lotus spreadsheet, data are compiled and an average accuracy is computed. If pairs of reference samples are analyzed, then precision can also be evaluated from the duplicate data sets. The standard deviation can be calculated if the reference concentrations of the duplicates are all in the same general range. Laboratory blanks are used to estimate the lower detection limits. The lower detection limit is calculated as 4.65 times the standard deviation of a set of blank determinations made over a given period of time. A Lotus spreadsheet is again used to compile data and LDLs over different periods of time can be compared

Improving the limits of detection of low background alpha emission measurements

Science.gov (United States)

McNally, Brendan D.; Coleman, Stuart; Harris, Jack T.; Warburton, William K.

2018-01-01

Alpha particle emission - even at extremely low levels - is a significant issue in the search for rare events (e.g., double beta decay, dark matter detection). Traditional measurement techniques require long counting times to measure low sample rates in the presence of much larger instrumental backgrounds. To address this, a commercially available instrument developed by XIA uses pulse shape analysis to discriminate alpha emissions produced by the sample from those produced by other surfaces of the instrument itself. Experience with this system has uncovered two residual sources of background: cosmogenics and radon emanation from internal components. An R&D program is underway to enhance the system and extend the pulse shape analysis technique further, so that these residual sources can be identified and rejected as well. In this paper, we review the theory of operation and pulse shape analysis techniques used in XIA's alpha counter, and briefly explore data suggesting the origin of the residual background terms. We will then present our approach to enhance the system's ability to identify and reject these terms. Finally, we will describe a prototype system that incorporates our concepts and demonstrates their feasibility.

Prediction of the limit of detection of an optical resonant reflection biosensor.

Science.gov (United States)

Hong, Jongcheol; Kim, Kyung-Hyun; Shin, Jae-Heon; Huh, Chul; Sung, Gun Yong

2007-07-09

A prediction of the limit of detection of an optical resonant reflection biosensor is presented. An optical resonant reflection biosensor using a guided-mode resonance filter is one of the most promising label-free optical immunosensors due to a sharp reflectance peak and a high sensitivity to the changes of optical path length. We have simulated this type of biosensor using rigorous coupled wave theory to calculate the limit of detection of the thickness of the target protein layer. Theoretically, our biosensor has an estimated ability to detect thickness change approximately the size of typical antigen proteins. We have also investigated the effects of the absorption and divergence of the incident light on the detection ability of the biosensor.

Comparative study of fix-installed monitoring instruments and its application in detecting uncontrolled trafficking of radioactive materials at airports

International Nuclear Information System (INIS)

Pujol, L.; Suarez-Navarro, M. J.; Gonzalez-Gonzalez, J. A.; Garcia-Galludo, M.

2010-01-01

In this paper we analyze the response of three commercial equipment designed to detect illicit trafficking or inadvertent movement of radioactive materials at airports when carried by passengers. We compared three fix-installed instruments: APM (Bicron), GR-606 (Exploranium), and FHT-1372 (Thermo Eberline). In this initial evaluation conducted at the Laboratory of Nuclear engineering of the School of Civil Engineering, it was observed that the FHT-1372 introduced a fester detection response, sensitive and allowed the measurement of total dose rate and artificial dose rate. This equipment was installed at the exit from customs passenger of Barajas international airport operating for a period of 108 days in 2002 with a total number of 1,339,931 people. this period was divided into 5 sessions to establish suitable investigation levels to detect a possible incident of radioactive material, which was finally set at 110 nSv/h to total dose rate and 25 nSv/h for artificial dose rate. During this period 39 possible incidents were detected above the investigation level established, 5 of them with a value 10 times the environmental background of the room where the equipment was installed (about 90 nSv/h), and no level exceeded 100 μSv/h at 1 m distance, which is the limit for legal transport of radioactive materials from the International Atomic Energy Agency (IAEA). (Author) 17 refs.

A Barrel IFR Instrumented With Limited Streamer Tubes for BABAR Experiment

International Nuclear Information System (INIS)

Andreotti, M.; Ferrara U.; INFN, Ferrara

2006-01-01

The new barrel Instrumented Flux Return (IFR) of BABAR detector will be reported here. Limited Streamer Tubes (LSTs) have been chosen to replace the existing RPCs as active elements of the barrel IFR. The layout of the new detector will be discussed: in particular, a cell bigger than the standard one has been used to improve efficiency and reliability. The extruded profile is coated with a resistive layer of graphite having a typical surface resistivity between 0.2 and 0.4 MOhm/square. The tubes are assembled in modules and installed in 12 active layers of each sextant of the IFR detector. R and D studies to choose the final design and Quality Control procedure adopted during the tube production will be briefly discussed. Finally the performances of installed LSTs into 2/3 of IFR after 8 months of operations will be reported

Instrument for long-path spectral extinction measurements in air: application to sizing of airborne particles

International Nuclear Information System (INIS)

Paganini, Enrico; Trespidi, Franco; Ferri, Fabio

2001-01-01

A novel instrument that is capable of taking spectral extinction measurements over long optical paths (approximately 1-100 m) in the UV, visible, and IR ranges is described. The instrument is fully automated, and the extinction spectrum is acquired in almost real time (approximately 5-10 s) with a resolution of ∼3 nm. Its sensitivity and accuracy were estimated by tests carried out in a clean room that showed that, for optical paths between 50 and 100 m, the extinction coefficient can be detected at levels of ∼10 -5 m -1 . Tests carried out on calibrated latex particles showed that, when it was combined with an appropriate inversion method, the technique could be profitably applied to characterize airborne particulate distributions. By carrying out measurements over optical paths of ∼100 m, the instrument is also capable of detecting extinction coefficients that are due to aerosol concentrations well below the limits imposed by the European Economic Community for atmospheric pollution (150 μg/m3). Scaled over optical paths of ∼10 m, the limit imposed for particle emissions from industrial plants (10 mg/m3) can also be detected sensitively

Possibilities for decreasing detection limits of analytical methods for determination of transformation products of unsymmetrical dimethylhydrazine in environmental samples

Directory of Open Access Journals (Sweden)

Bulat Kenessov

2015-12-01

Full Text Available Most rockets of middle and heavy class launched from Kazakhstan, Russia, China and other countries still use highly toxic unsymmetrical dimethylhydrazine (UDMH as a liquid propellant. Study of migration, distribution and accumulation of UDMH transformation products in environment and human health impact assessment of space rocket activity are currently complicated due to the absence of analytical methods allowing detection of trace concentrations of these compounds in analyzed samples. This paper reviews methods and approaches, which can be applied for development of such methods. Detection limits at a part-per-trillion (ppt level may be achieved using most selective and sensitive methods based on gas or liquid chromatography in combination of tandem or high-resolution mass spectrometry. In addition, 1000-fold concentration of samples or integrated sample preparation methods, e.g., dynamic headspace extraction, are required. Special attention during development and application of such methods must be paid to purity of laboratory air, reagents, glassware and analytical instruments.

Standard guide for evaluating performance characteristics of phased-Array ultrasonic testing instruments and systems

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This guide describes procedures for evaluating some performance characteristics of phased-array ultrasonic examination instruments and systems. 1.2 Evaluation of these characteristics is intended to be used for comparing instruments and systems or, by periodic repetition, for detecting long-term changes in the characteristics of a given instrument or system that may be indicative of impending failure, and which, if beyond certain limits, will require corrective maintenance. Instrument characteristics measured in accordance with this guide are expressed in terms that relate to their potential usefulness for ultrasonic examinations. Other electronic instrument characteristics in phased-array units are similar to non-phased-array units and may be measured as described in E 1065 or E 1324. 1.3 Ultrasonic examination systems using pulsed-wave trains and A-scan presentation (rf or video) may be evaluated. 1.4 This guide establishes no performance limits for examination systems; if such acceptance criteria ar...

Measurement of activity limitations and participation restrictions: examination of ICF-linked content and scale properties of the FIM and PC-PART instruments.

Science.gov (United States)

Darzins, Susan W; Imms, Christine; Di Stefano, Marilyn

2017-05-01

To explore the operationalization of activity and participation-related measurement constructs through comparison of item phrasing, item response categories and scoring (scale properties) for two separate instruments targeting activities of daily living. Personal Care Participation Assessment and Resource Tool (PC-PART) item content was linked to ICF categories using established linking rules. Previously reported ICF-linked FIM content categories and ICF-linked PC-PART content categories were compared to identify common ICF categories between the instruments. Scale properties of both instruments were compared using a patient scenario to explore the instruments' separate measurement constructs. The PC-PART and FIM shared 15 of the 53 level two ICF-linked categories identified across both instruments. Examination of the instruments' scale properties for items with overlapping ICF content, and exploration through a patient scenario, provided supportive evidence that the instruments measure different constructs. While the PC-PART and FIM share common ICF-linked content, they measure separate constructs. Measurement construct was influenced by the instruments' scale properties. The FIM was observed to measure activity limitations and the PC-PART measured participation restrictions. Scrutiny of instruments' scale properties in addition to item content is critical in the operationalization of activity and participation-related measurement constructs. Implications for Rehabilitation When selecting outcome measures for use in rehabilitation it is necessary to examine both the content of the instruments' items and item phrasing, response categories and scoring, to clarify the construct being measured. Measurement of activity limitations as well as participation restrictions in activities of daily living required for community life provides a more comprehensive measurement of rehabilitation outcomes than measurement of either construct alone. To measure the effects of

Instrument failure detection of flow measurement in the feedwater system of the Paks Nuclear Power Plant, Hungary

International Nuclear Information System (INIS)

Racz, A.

1990-12-01

The applicability of two different methods for early detection of instrument failures of the flow measurement in feedwater systems are investigated. Both methods are based on Kalman filtering technique of stochastic processes. The reliability of the model for description of a feedwater system is checked by comparing calculated values with measured data. Possible instrument failures are simulated in order to show the capability of the proposed procedures. A practical measurement system arrangement is suggested. (author) 10 refs.; 16 figs.; 4 tabs

Evaluation of the current fast neutron flux monitoring instrumentation applied to LFR demonstrator ALFRED. Capabilities and limitations

International Nuclear Information System (INIS)

Lepore, Luigi; Remetti, Romolo; Cappelli, Mauro

2015-01-01

Among Gen IV projects for future nuclear power plants, Lead Fast Reactors (LFR) seem to be a very interesting solution due to their benefits in terms of fuel cycle, coolant-safety and waste management. The novelty of the matter causes some open issues about coolant chemical aspect, structural aspects, monitoring instrumentation, etc. Particularly hard neutron flux spectra would make traditional neutron instrumentation unfit to all reactor conditions, i.e. source, intermediate, and power range. Identification of new models of nuclear instrumentation specialized for LFR neutron flux monitoring asks for an accurate evaluation of the environment the sensor will work in. In this study, thermal-hydraulics and chemical conditions for LFR core environment will be assumed, as the neutron flux will be studied extensively by means of the Monte Carlo transport code MCNPX. The core coolant’s high temperature drastically reduces the candidate instrumentation, because only some kind of fission chambers and Self Powered Neutron Detectors can be operated in such an environment. This work aims to evaluate the capabilities of the available instrumentation (usually designed for Sodium Fast Reactors, SFRs) when exposed to the neutron spectrum derived from ALFRED, a pool-type small-power LFR project to demonstrate the feasibility of this technology into the European framework. This paper shows that such instruments do follow the power evolution, but they are not completely suitable to detect the whole range of reactor power. Some improvements are then possible in order to increase the signal-to-noise ratio, by optimizing each instrument in the range of reactor power, such to get the best solution. Some new detector designs are here proposed, and the possibilities for prototyping and testing by means of a fast reactor investigated. (author)

Identification of inorganic improvised explosive devices by analysis of postblast residues using portable capillary electrophoresis instrumentation and indirect photometric detection with a light-emitting diode.

Science.gov (United States)

Hutchinson, Joseph P; Evenhuis, Christopher J; Johns, Cameron; Kazarian, Artaches A; Breadmore, Michael C; Macka, Miroslav; Hilder, Emily F; Guijt, Rosanne M; Dicinoski, Greg W; Haddad, Paul R

2007-09-15

A commercial portable capillary electrophoresis (CE) instrument has been used to separate inorganic anions and cations found in postblast residues from improvised explosive devices (IEDs) of the type used frequently in terrorism attacks. The purpose of this analysis was to identify the type of explosive used. The CE instrument was modified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirect photometric detection to be employed for the detection of 15 anions (acetate, benzoate, carbonate, chlorate, chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and 12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium, magnesium, manganese, calcium, zinc, lead) as the target analytes. These ions are known to be present in postblast residues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, and chlorate/perchlorate/sugar mixtures. For the analysis of cations, a blue LED (470 nm) was used in conjunction with the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine in methanol was found to give greatly improved baseline stability in comparison to aqueous electrolytes due to the increased solubility of chrysoidine and its decreased adsorption onto the capillary wall. Glacial acetic acid (0.7% v/v) was added to ensure chrysoidine was protonated and to enhance separation selectivity by means of complexation with transition metal ions. The 12 target cations were separated in less than 9.5 min with detection limits of 0.11-2.30 mg/L (calculated at a signal-to-noise ratio of 3). The anions separation system utilized a UV LED (370 nm) in conjunction with an aqueous chromate electrolyte (absorption maximum at 371 nm) consisting of 10 mM chromium(VI) oxide and 10 mM sodium chromate, buffered with 40 mM tris

Improvement in Limit of Detection of Enzymatic Biogas Sensor Utilizing Chromatography Paper for Breath Analysis.

Science.gov (United States)

Motooka, Masanobu; Uno, Shigeyasu

2018-02-02

Breath analysis is considered to be an effective method for point-of-care diagnosis due to its noninvasiveness, quickness and simplicity. Gas sensors for breath analysis require detection of low-concentration substances. In this paper, we propose that reduction of the background current improves the limit of detection of enzymatic biogas sensors utilizing chromatography paper. After clarifying the cause of the background current, we reduced the background current by improving the fabrication process of the sensors utilizing paper. Finally, we evaluated the limit of detection of the sensor with the sample vapor of ethanol gas. The experiment showed about a 50% reduction of the limit of detection compared to previously-reported sensor. This result presents the possibility of the sensor being applied in diagnosis, such as for diabetes, by further lowering the limit of detection.

Microbial Habitability in Gale Crater: Sample Analysis at Mars (SAM) Instrument Detection of Microbial Essential Carbon and Nitrogen

Science.gov (United States)

Sutter, B.; Ming, D. W.; Eigenbrode, J. E.; Steele, A.; Stern, J. C.; Gonzalez, R. N.; McAdam, A. C.; Mahaffy, P. R.

2016-01-01

Chemical analyses of Mars soils and sediments from previous landed missions have demonstrated that Mars surface materials possessed major (e.g., P, K, Ca, Mg, S) and minor (e.g., Fe, Mn, Zn, Ni, Cl) elements essential to support microbial life. However, the detection of microbial essential organic-carbon (C) and nitrate have been more elusive until the Mars Science Laboratory (MSL) rover mission. Nitrate and organic-C in Gale Crater, Mars have been detected by the Sample Analysis at Mars (SAM) instrument onboard the MSL Curiosity rover. Eolian fines and drilled sedimentary rock samples were heated in the SAM oven from approximately 30 to 860 degrees Centigrade where evolved gases (e.g., nitrous oxide (NO) and CO2) were released and analyzed by SAM’s quadrupole mass spectrometer (MS). The temperatures of evolved NO was assigned to nitrate while evolved CO2 was assigned to organic-C and carbonate. The CO2 releases in several samples occurred below 450 degrees Centigrade suggesting organic-C dominated in those samples. As much as 7 micromoles NO3-N per gram and 200 micromoles CO2-C per gram have been detected in the Gale Crater materials. These N and C levels coupled with assumed microbial biomass (9 x 10 (sup -7) micrograms per cell) C (0.5 micrograms C per micrograms cell) and N (0.14 micrograms N per micrograms cell) requirements, suggests that less than 1 percent and less than 10 percent of Gale Crater C and N, respectively, would be required if available, to accommodate biomass requirements of 1 by 10 (sup 5) cells per gram sediment. While nitrogen is the limiting nutrient, the potential exists that sufficient N and organic-C were present to support limited heterotrophic microbial populations that may have existed on ancient Mars.

Determining the lower limit of detection for personnel dosimetry systems

International Nuclear Information System (INIS)

Roberson, P.L.; Carlson, R.D.

1992-01-01

A simple method for determining the lower limit of detection (LLD) for personnel dosimetry systems is described. The method relies on the definition of a critical level and a detection level. The critical level is the signal level above which a result has a small probability of being due to a fluctuation of the background. All results below the critical level should not be reported as an indication of a positive result. The detection level is the net signal level (i.e., dose received) above which there is a high confidence that a true reading will be detected and reported as a qualitatively positive result. The detection level may be identified as the LLD. A simple formula is derived to allow the calculation of the LLD under various conditions. This type of formula is being used by the Department of Energy Laboratory Accreditation Program (DOELAP) for personnel dosimetry. Participants in either the National Voluntary Laboratory Accreditation Program (NVLAP) for personnel dosimetry or DOELAP can use performance test results along with a measurement of background levels to estimate the LLDs for their dosimetry system. As long as they maintain their dosimetry system such that the LLDs are less than half the lower limit of the NVLAP or DOELAP test exposure ranges, dosimetry laboratories can avoid testing failures due to poor performance at very low exposures

Visualizing the Limits of Low Vision in Detecting Natural Image Features

NARCIS (Netherlands)

Hogervorst, M.A.; Damme, W.J.M. van

2008-01-01

Purpose. The purpose of our study was to develop a tool to visualize the limitations posed by visual impairments in detecting small and low-contrast elements in natural images. This visualization tool incorporates existing models of several aspects of visual perception, such as the band-limited

Proof-testing strategies induced by dangerous detected failures of safety-instrumented systems

International Nuclear Information System (INIS)

Liu, Yiliu; Rausand, Marvin

2016-01-01

Some dangerous failures of safety-instrumented systems (SISs) are detected almost immediately by diagnostic self-testing as dangerous detected (DD) failures, whereas other dangerous failures can only be detected by proof-testing, and are therefore called dangerous undetected (DU) failures. Some items may have a DU- and a DD-failure at the same time. After the repair of a DD-failure is completed, the maintenance team has two options: to perform an insert proof test for DU-failure or not. If an insert proof test is performed, it is necessary to decide whether the next scheduled proof test should be postponed or performed at the scheduled time. This paper analyzes the effects of different testing strategies on the safety performance of a single channel of a SIS. The safety performance is analyzed by Petri nets and by approximation formulas and the results obtained by the two approaches are compared. It is shown that insert testing improves the safety performance of the channel, but the feasibility and cost of the strategy may be a hindrance to recommend insert testing. - Highlights: • Identify the tests induced by detected failures. • Model the testing strategies following DD-failures. • Propose analytical formulas for effects of strategies. • Simulate and verify the proposed models.

Minimum detection limit and spatial resolution of thin-sample field-emission electron probe microanalysis

International Nuclear Information System (INIS)

Kubo, Yugo; Hamada, Kotaro; Urano, Akira

2013-01-01

The minimum detection limit and spatial resolution for a thinned semiconductor sample were determined by electron probe microanalysis (EPMA) using a Schottky field emission (FE) electron gun and wavelength dispersive X-ray spectrometry. Comparison of the FE-EPMA results with those obtained using energy dispersive X-ray spectrometry in conjunction with scanning transmission electron microscopy, confirmed that FE-EPMA is largely superior in terms of detection sensitivity. Thin-sample FE-EPMA is demonstrated as a very effective method for high resolution, high sensitivity analysis in a laboratory environment because a high probe current and high signal-to-noise ratio can be achieved. - Highlights: • Minimum detection limit and spatial resolution determined for FE-EPMA. • Detection sensitivity of FE-EPMA greatly superior to that of STEM-EDX. • Minimum detection limit and spatial resolution controllable by probe current

Calculation of risk-based detection limits for radionuclides in the liquid effluents from Korean nuclear power plants

International Nuclear Information System (INIS)

Cheong, Jae Hak

2017-01-01

In order to review if present detection limits of radionuclides in liquid effluent from nuclear power plants are effective enough to warrant compliance with regulatory discharge limits, a risk-based approach is developed to derive a new detection limit for each radionuclide based on radiological criteria. Equations and adjustment factors are also proposed to discriminate the validity of the detection limits for multiple radionuclides in the liquid effluent with or without consideration of the nuclide composition. From case studies to three nuclear power plants in Korea with actual operation data from 2006 to 2015, the present detection limits have turned out to be effective for Hanul Unit 1 but may not be sensitive enough for Kori Unit 1 (8 out of 14 radionuclides) and Wolsong Unit 1 (9 out of 42 radionuclides). However, it is shown that the present detection limits for the latter two nuclear power plants can be justified, if credit is given to the radionuclide composition. Otherwise, consideration should be given to adjustment of the present detection limits. The risk-based approach of this study can be used to determine the validity of established detection limits of a specific nuclear power plant. (author)

Gold nanoparticle-based low limit of detection Love wave biosensor for carcinoembryonic antigens.

Science.gov (United States)

Li, Shuangming; Wan, Ying; Su, Yan; Fan, Chunhai; Bhethanabotla, Venkat R

2017-09-15

In this work, a Love wave biosensing platform is described for detecting cancer-related biomarker carcinoembryonic antigen (CEA). An ST 90°-X quartz Love wave device with a layer of SiO 2 waveguide was combined with gold nanoparticles (Au NPs) to amplify the mass loading effect of the acoustic wave sensor to achieve a limit of detection of 37pg/mL. The strategy involves modifying the Au NPs with anti-CEA antibody conjugates to form nanoprobes in a sandwich immunoassay. The unamplified detection limit of the Love wave biosensor is 9.4ng/mL. This 2-3 order of magnitude reduction in the limit of detection brings the SAW platform into the range useful for clinical diagnosis. Measurement electronics and microfluidics are easily constructed for acoustic wave biosensors, such as the Love wave device described here, allowing for robust platforms for point of care applications for cancer biomarkers in general. Copyright © 2017 Elsevier B.V. All rights reserved.

Design and Implementation of Electric Steering Gear Inspection System for Unmanned Aerial Vehicles Based on Virtual Instruments

Directory of Open Access Journals (Sweden)

Zheng Xing

2016-01-01

Full Text Available A kind of UAV electric servo detection system based on Virtual Instrument is designed in this paper, including the hardware platform based on PC-DAQ virtual instrument architecture and the software platform based on LabVIEW function, structure and system implementation methods. The function, structure and system implementation method of software platform is also described. The gear limits checking, zero testing, time domain characteristics test results showed that the system achieves testing requirements well, and can complete detection of electric steering gear automatically, fast, easy and accurate.

Surgical instrument biocontaminant fluorescence detection in ambient lighting conditions for hospital reprocessing and sterilization department (Conference Presentation)

Science.gov (United States)

Baribeau, François; Bubel, Annie; Dumont, Guillaume; Vachon, Carl; Lépine, André; Rochefort, Stéphane; Massicotte, Martin; Buteau-Vaillancourt, Louis; Gallant, Pascal; Mermut, Ozzy

2017-03-01

Hospitals currently rely on simple human visual inspection for assessing cleanliness of surgical instruments. Studies showed that surgical site infections are in part attributed to inadequate cleaning of medical devices. Standards groups recognize the need to objectively quantify the amount of residues on surgical instruments and establish guidelines. We developed a portable technology for the detection of contaminants on surgical instruments through fluorescence following cleaning. Weak fluorescence signals are usually detected in the obscurity only with the lighting of the excitation source. The key element of this system is that it works in ambient lighting conditions, a requirement to not disturb the normal workflow of hospital reprocessing facilities. A biocompatible fluorescent dye is added to the detergent and labels the proteins of organic residues. It is resistant to the harsh environment in a washer-disinfector. Two inspection devices have been developed with a 488nm laser as the excitation source: a handheld scanner and a tabletop station using spectral-domain and time-domain ambient light cancellation schemes. The systems are eye safe and equipped with image processing and interfacing software to provide visual or audible warnings to the operator based on a set of adjustable signal thresholds. Micron-scale residues are detected by the system which can also evaluate soil size and mass. Unlike swabbing, it can inspect whole tools in real-time. The technology has been validated in an independent hospital decontamination research laboratory. It also has potential applications in the forensics, agro-food, and space fields. Technical aspects and results will be presented and discussed.

Detection limit of 238U by gamma spectrometry

International Nuclear Information System (INIS)

Tartaglione, A.; Blostein, J.; Mayer, R

2004-01-01

The detection limit of 238 U was determined by gamma spectra measurements of a depleted uranium sample using four NaI(Tl) scintillators in a compact arrangement.The sample was shielded with 5 and 10 cm of lead.Two different methods for data processing were used and compared.It was established that an appropriate array of 40 detectors could establish the presence of 220 g of this material in only 5 minutes [es

Detection of flux perturbations in pebble bed HTGRs by near core instrumentation

International Nuclear Information System (INIS)

Neef, R.D.; Basse, W.; Carlson, D.E.; Knob, P.; Schaal, H.; Wilhelm, H.; Stroemich, A.

1982-06-01

For pebble bed reactors an incore monitoring system cannot be utilized during normal operation, mainly for two reasons: 1) The necessary instrumentation cannot withstand possible coolant gas temperatures of up to 1150 deg. C. 2) The detector guide structures cannot withstand the continuous downward movement of the fuel elements in the core and would perturb the loading scheme. Therefore a near-core detector system is necessary which can be used to monitor the power distribution and to recognise perturbations in the neutron flux distribution. This helps guarantee that temperature limits in the core (fuel elements, absorber rods) and in the heat removal systems (steam generators) will not be exceeded. For this purpose an instrumentation system of the following kind is planned (and at least for a prototype reactor no part of it should be omitted): 1) Fast fission chambers in the top reflector for measuring the fast neutron flux distribution; 2) Self powered neutron detectors (SPNDs) in the radial reflector for thermal flux mapping; 3) Thermocouples in the bottom reflector for measuring the profile of the outlet gas temperature

Practical low dose limits for passive personal dosemeters and the implications for uncertainties close to the limit of detection

International Nuclear Information System (INIS)

Gilvin, P. J.; Perks, C. A.

2011-01-01

Recent years have seen the increasing use of passive dosemeters that have high sensitivities and, in laboratory conditions, detection limits of <10 μSv. However, in real operational use the detection limits will be markedly higher, because a large fraction of the accrued dose will be due to natural background, and this must be subtracted in order to obtain the desired occupational dose. No matter how well known the natural background is, the measurement uncertainty on doses of a few tens of microsieverts will be large. Individual monitoring services need to recognise this and manage the expectations of their clients by providing sufficient information. (authors)

Sensitive detection and separation of fluorescent derivatives using capillary electrophoresis with laser-induced fluorescence detection with 532nm Nd:YAG laser

International Nuclear Information System (INIS)

Vrabel, Patrik; Taborsky, Petr; Ryvolova, Marketa; Havel, Josef; Preisler, Jan

2006-01-01

Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary. In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2x10 -13 mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar + laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed

Electrochemical Microsensors for the Detection of Cadmium(II and Lead(II Ions in Plants

Directory of Open Access Journals (Sweden)

Olga Krystofova

2010-05-01

Full Text Available Routine determination of trace metals in complex media is still a difficult task for many analytical instruments. The aim of this work was to compare three electro-chemical instruments [a standard potentiostat (Autolab, a commercially available miniaturized potentiostat (PalmSens and a homemade micropotentiostat] for easy-to-use and sensitive determination of cadmium(II and lead(II ions. The lowest detection limits (hundreds of pM for both metals was achieved by using of the standard potentiostat, followed by the miniaturized potentiostat (tens of nM and the homemade instrument (hundreds of nM. Nevertheless, all potentiostats were sensitive enough to evaluate contamination of the environment, because the environmental limits for both metals are higher than detection limits of the instruments. Further, we tested all used potentiostats and working electrodes on analysis of environmental samples (rainwater, flour and plant extract with artificially added cadmium(II and lead(II. Based on the similar results obtained for all potentiostats we choose a homemade instrument with a carbon tip working electrode for our subsequent environmental experiments, in which we analyzed maize and sunflower seedlings and rainwater obtained from various sites in the Czech Republic.

Instrument for bone mineral measurement using a microprocessor as the control and arithmetic element

International Nuclear Information System (INIS)

Alberi, J.L.; Hardy, W.H. II.

1975-11-01

A self-contained instrument for the determination of bone mineral content by photon absorptometry is described. A high-resolution detection system allows measurements to be made at up to 16 photon energies. Control and arithmetic functions are performed by a microprocessor. Analysis capability and limitations are discussed

Determination and Interpretation of Characteristic Limits for Radioactivity Measurements: Decision Threshhold, Detection Limit and Limits of the Confidence Interval

International Nuclear Information System (INIS)

2017-01-01

Since 2004, the environment programme of the IAEA has included activities aimed at developing a set of procedures for analytical measurements of radionuclides in food and the environment. Reliable, comparable and fit for purpose results are essential for any analytical measurement. Guidelines and national and international standards for laboratory practices to fulfil quality assurance requirements are extremely important when performing such measurements. The guidelines and standards should be comprehensive, clearly formulated and readily available to both the analyst and the customer. ISO 11929:2010 is the international standard on the determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measuring ionizing radiation. For nuclear analytical laboratories involved in the measurement of radioactivity in food and the environment, robust determination of the characteristic limits of radioanalytical techniques is essential with regard to national and international regulations on permitted levels of radioactivity. However, characteristic limits defined in ISO 11929:2010 are complex, and the correct application of the standard in laboratories requires a full understanding of various concepts. This publication provides additional information to Member States in the understanding of the terminology, definitions and concepts in ISO 11929:2010, thus facilitating its implementation in Member State laboratories.

Near-infrared incoherent broadband cavity enhanced absorption spectroscopy (NIR-IBBCEAS) for detection and quantification of natural gas components.

Science.gov (United States)

Prakash, Neeraj; Ramachandran, Arun; Varma, Ravi; Chen, Jun; Mazzoleni, Claudio; Du, Ke

2018-06-28

The principle of near-infrared incoherent broadband cavity enhanced absorption spectroscopy was employed to develop a novel instrument for detecting natural gas leaks as well as for testing the quality of natural gas mixtures. The instrument utilizes the absorption features of methane, butane, ethane, and propane in the wavelength region of 1100 nm to 1250 nm. The absorption cross-section spectrum in this region for methane was adopted from the HITRAN database, and those for the other three gases were measured in the laboratory. A singular-value decomposition (SVD) based analysis scheme was employed for quantifying methane, butane, ethane, and propane by performing a linear least-square fit. The developed instrument achieved a detection limit of 460 ppm, 141 ppm, 175 ppm and 173 ppm for methane, butane, ethane, and propane, respectively, with a measurement time of 1 second and a cavity length of 0.59 m. These detection limits are less than 1% of the Lower Explosive Limit (LEL) for each gas. The sensitivity can be further enhanced by changing the experimental parameters (such as cavity length, lamp power etc.) and using longer averaging intervals. The detection system is a low-cost and portable instrument suitable for performing field monitorings. The results obtained on the gas mixture emphasize the instrument's potential for deployment at industrial facilities dealing with natural gas, where potential leaks pose a threat to public safety.

Detectors for Tomorrow's Instruments

Science.gov (United States)

Moseley, Harvey

2009-01-01

Cryogenically cooled superconducting detectors have become essential tools for a wide range of measurement applications, ranging from quantum limited heterodyne detection in the millimeter range to direct searches for dark matter with superconducting phonon detectors operating at 20 mK. Superconducting detectors have several fundamental and practical advantages which have resulted in their rapid adoption by experimenters. Their excellent performance arises in part from reductions in noise resulting from their low operating temperatures, but unique superconducting properties provide a wide range of mechanisms for detection. For example, the steep dependence of resistance with temperature on the superconductor/normal transition provides a sensitive thermometer for calorimetric and bolometric applications. Parametric changes in the properties of superconducting resonators provides a mechanism for high sensitivity detection of submillimeter photons. From a practical point of view, the use of superconducting detectors has grown rapidly because many of these devices couple well to SQUID amplifiers, which are easily integrated with the detectors. These SQUID-based amplifiers and multiplexers have matured with the detectors; they are convenient to use, and have excellent noise performance. The first generation of fully integrated large scale superconducting detection systems are now being deployed. I will discuss the prospects for a new generation of instruments designed to take full advantage of the revolution in detector technology.

Basics of radiation physics and instrumentation

International Nuclear Information System (INIS)

Royal, H.D.

1985-01-01

Continued technical developments are greatly changing medical diagnosis and medical care. In the field of cardiology, a number of new imaging techniques are currently available. This chapter reviews several topics that are important in the practice of nuclear cardiology. The first section discusses some of the basics of nuclear physics. Familiarity with these fundamentals is essential for an in-depth understanding of nuclear cardiology. The second section presents information on radiotracers and provides dosimetry estimates for commonly performed studies. The third section reviews the instruments used to detect radioactivity. The final section discusses computers and their applications and limitations in nuclear cardiology

Weighted Polynomial Approximation for Automated Detection of Inspiratory Flow Limitation

Directory of Open Access Journals (Sweden)

Sheng-Cheng Huang

2017-01-01

Full Text Available Inspiratory flow limitation (IFL is a critical symptom of sleep breathing disorders. A characteristic flattened flow-time curve indicates the presence of highest resistance flow limitation. This study involved investigating a real-time algorithm for detecting IFL during sleep. Three categories of inspiratory flow shape were collected from previous studies for use as a development set. Of these, 16 cases were labeled as non-IFL and 78 as IFL which were further categorized into minor level (20 cases and severe level (58 cases of obstruction. In this study, algorithms using polynomial functions were proposed for extracting the features of IFL. Methods using first- to third-order polynomial approximations were applied to calculate the fitting curve to obtain the mean absolute error. The proposed algorithm is described by the weighted third-order (w.3rd-order polynomial function. For validation, a total of 1,093 inspiratory breaths were acquired as a test set. The accuracy levels of the classifications produced by the presented feature detection methods were analyzed, and the performance levels were compared using a misclassification cobweb. According to the results, the algorithm using the w.3rd-order polynomial approximation achieved an accuracy of 94.14% for IFL classification. We concluded that this algorithm achieved effective automatic IFL detection during sleep.

Instrumentation for environmental monitoring: biomedical

International Nuclear Information System (INIS)

1979-05-01

An update is presented to Volume four of the six-volume series devoted to a survey of instruments useful for measurements in biomedicine related to environmental research and monitoring. Results of the survey are given as descriptions of the physical and operating characteristics of available instruments, critical comparisons among instrumentation methods, and recommendations of promising methodology and development of new instrumentation. Methods of detection and analysis of gaseous organic pollutants and metals, including Ni and As are presented. Instrument techniques and notes are included on atomic spectrometry and uv and visible absorption instrumentation

[Evaluation of Medical Instruments Cleaning Effect of Fluorescence Detection Technique].

Science.gov (United States)

Sheng, Nan; Shen, Yue; Li, Zhen; Li, Huijuan; Zhou, Chaoqun

2016-01-01

To compare the cleaning effect of automatic cleaning machine and manual cleaning on coupling type surgical instruments. A total of 32 cleaned medical instruments were randomly sampled from medical institutions in Putuo District medical institutions disinfection supply center. Hygiena System SUREII ATP was used to monitor the ATP value, and the cleaning effect was evaluated. The surface ATP values of the medical instrument of manual cleaning were higher than that of the automatic cleaning machine. Coupling type surgical instruments has better cleaning effect of automatic cleaning machine before disinfection, the application is recommended.

Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10−6

Directory of Open Access Journals (Sweden)

Gang Zhao

2016-09-01

Full Text Available A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS instrumentation, based on a distributed feedback (DFB diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN. The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz, followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS can be swiftly performed down to a limit of detection (LOD (1σ of 4 × 10−6, which opens up a number of new applications.

Including Below Detection Limit Samples in Post Decommissioning Soil Sample Analyses

Energy Technology Data Exchange (ETDEWEB)

Kim, Jung Hwan; Yim, Man Sung [KAIST, Daejeon (Korea, Republic of)

2016-05-15

To meet the required standards the site owner has to show that the soil at the facility has been sufficiently cleaned up. To do this one must know the contamination of the soil at the site prior to clean up. This involves sampling that soil to identify the degree of contamination. However there is a technical difficulty in determining how much decontamination should be done. The problem arises when measured samples are below the detection limit. Regulatory guidelines for site reuse after decommissioning are commonly challenged because the majority of the activity in the soil at or below the limit of detection. Using additional statistical analyses of contaminated soil after decommissioning is expected to have the following advantages: a better and more reliable probabilistic exposure assessment, better economics (lower project costs) and improved communication with the public. This research will develop an approach that defines an acceptable method for demonstrating compliance of decommissioned NPP sites and validates that compliance. Soil samples from NPP often contain censored data. Conventional methods for dealing with censored data sets are statistically biased and limited in their usefulness.

New-generation low-power radiation survey instruments

International Nuclear Information System (INIS)

Waechter, D.A.; Bjarke, G.O.; Wolf, M.A.; Trujillo, F.; Umbarger, C.J.

1983-01-01

A number of new, ultra-low-powered radiation instruments have recently been developed at Los Alamos. Among these are two instruments which use a novel power source to eliminate costly batteries. The newly developed gamma detecting radiac, nicknamed the Firefly, and the alpha particle detecting instrument, called the Simple Cordless Alpha Monitor, both use recent advances in miniaturization and power-saving electronics to yield devices which are small, rugged, and very power-frugal. The two instruments consume so little power that the need for batteries to run them is eliminated. They are, instead, powered by a charged capacitor which will operate the instruments for an hour or more. Both line power and mechanical sources are used to charge the storage capacitors which power the instruments

The Scope and Limitations of Legal Instruments on Cultural Property in the World Heritage City of Vigan, Philippines

Directory of Open Access Journals (Sweden)

Yahaya Ahmad

2005-12-01

Full Text Available The World Heritage City of Vigan. Philippines was inscribed in the list of World Heritage Sites in 1999 under criteria (ii and (iv of the Operational Guidelines, after its first submission in 1989 was rejected by the World Heritage Committee. The heritage of the city is now sufficiently protected by eight legal instruments, four enacted at national level and an other four at local level. However, these instruments have limited scope and limitation and, if not rectified, will not be able to safeguard the heritage of the City against rapid development. Presidential Decree No. 374/1974, which has not been revised, has several weaknesses, such as in system of incentives, penalties, the broad terminology and scope of heritage as well as overlapping of tasks and responsibilities between national agencies. The main Local Ordinance No. 04/2000: An Ordinance Enacting the Preservation and Conservation Guidelines for Vigan Ancestral Houses provides solid guidance on the protection of heritage but requires revision related to Section 2 on Definition of Ancestral Houses, Sections 3-16 on Technical Guidelines, Sections 17-22 on Vigan Conservation Council and Section 24 on Penalties.

Detection limit for rate fluctuations in inhomogeneous Poisson processes

Science.gov (United States)

Shintani, Toshiaki; Shinomoto, Shigeru

2012-04-01

Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

Detection limit for rate fluctuations in inhomogeneous Poisson processes.

Science.gov (United States)

Shintani, Toshiaki; Shinomoto, Shigeru

2012-04-01

Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

Improved detection limits for phthalates by selective solid-phase micro-extraction

KAUST Repository

Zia, Asif I.; Afsarimanesh, Nasrin; Xie, Li; Nag, Anindya; Al-Bahadly, I. H.; Yu, P. L.; Kosel, Jü rgen

2016-01-01

Presented research reports on an improved method and enhanced limits of detection for phthalates; a hazardous additive used in the production of plastics by solid-phase micro-extraction (SPME) polymer in comparison to molecularly imprinted solid

Nuclear instrumentation for radiation measurement

International Nuclear Information System (INIS)

Madan, V.K.

2012-01-01

Nuclear radiation cannot be detected by human senses. Nuclear detectors and associated electronics facilitate detection and measurement of different types of radiation like alpha particles, beta particles, gamma radiation, and detection of neutrons. Nuclear instrumentation has evolved greatly since the discovery of radioactivity. There has been tremendous advancement in detector technology, electronics, computer technology, and development of efficient algorithms and methods for spectral processing to extract precisely qualitative and quantitative information of the radiation. Various types of detectors and nuclear instruments are presently available and are used for different applications. This paper describes nuclear radiation, its detection and measurement and associated electronics, spectral information extraction, and advances in these fields. The paper also describes challenges in this field

Limitation of liability for maritime claims: Chronological critical review (international instruments and Croatian solutions

Directory of Open Access Journals (Sweden)

Vasilj Aleksandra V.

2016-01-01

Full Text Available Limitation of liability of shipowner can based on property or can be personal - shipowner responds to certain part of the property (for example ship or his entire assets to a certain amount. In the first case it is a real, and in the other the personal limitation of liability. On these principles all international instruments in this legal field have been developed. One of the well-known 'universal' principle of civil law says that the injurer must pay for a damage in full, in full extent and amount. However, when we are applying provisions of maritime law (as well as transport law in general on the liability for damages and its compensation, the situation is quite opposite. Though, that the amount of suffered damages is coming closer to said universal principle of civil law has been confirmed by Amendments to the Protocol to the Convention on Limitation of Liability for Maritime Claims 1996 (LLMC 1996. These Amendments increased amount of general (global limitation of liability for maritime claims by 51% compared to the amounts in LLMC. Increased amounts are applicable from 8th June 2015. Regarding these amendments, a number of issues can be placed: justification for introducing the institute of limitation of liability in general; reasons why the injurer is privileged in maritime (and broader in transport, in the context of the amount of the obligation of compensation for damage; and whether the application of the institute undermine the principle that is enshrined in the legal system of every modern country, according to which the injured party has the right to just compensation. On the other hand, justice can be taken as well as an argument just to implement the limitation of liability system.

Fabrication of Stretchable Copper Coated Carbon Nanotube Conductor for Non-Enzymatic Glucose Detection Electrode with Low Detection Limit and Selectivity

Directory of Open Access Journals (Sweden)

Dawei Jiang

2018-03-01

Full Text Available The increasing demand for wearable glucose sensing has stimulated growing interest in stretchable electrodes. The development of the electrode materials having large stretchability, low detection limit, and good selectivity is the key component for constructing high performance wearable glucose sensors. In this work, we presented fabrication of stretchable conductor based on the copper coated carbon nanotube sheath-core fiber, and its application as non-enzymatic electrode for glucose detection with high stretchability, low detection limit, and selectivity. The sheath-core fiber was fabricated by coating copper coated carbon nanotube on a pre-stretched rubber fiber core followed by release of pre-stretch, which had a hierarchically buckled structure. It showed a small resistance change as low as 27% as strain increasing from 0% to 500% strain, and a low resistance of 0.4 Ω·cm−1 at strain of 500%. This electrode showed linear glucose concentration detection in the range between 0.05 mM and 5 mM and good selectivity against sucrose, lactic acid, uric acid, acrylic acid in phosphate buffer saline solution, and showed stable signal in high salt concentration. The limit of detection (LOD was 0.05 mM, for the range of 0.05–5 mM, the sensitivity is 46 mA·M−1. This electrode can withstand large strain of up to 60% with negligible influence on its performance.

Detecting charging state of ultra-fine particles: instrumental development and ambient measurements

Directory of Open Access Journals (Sweden)

L. Laakso

2007-01-01

Full Text Available The importance of ion-induced nucleation in the lower atmosphere has been discussed for a long time. In this article we describe a new instrumental setup – Ion-DMPS – which can be used to detect contribution of ion-induced nucleation on atmospheric new particle formation events. The device measures positively and negatively charged particles with and without a bipolar charger. The ratio between "charger off" to "charger on" describes the charging state of aerosol particle population with respect to equilibrium. Values above one represent more charges than in an equilibrium (overcharged state, and values below unity stand for undercharged situation, when there is less charges in the particles than in the equilibrium. We performed several laboratory experiments to test the operation of the instrument. After the laboratory tests, we used the device to observe particle size distributions during atmospheric new particle formation in a boreal forest. We found that some of the events were clearly dominated by neutral nucleation but in some cases also ion-induced nucleation contributed to the new particle formation. We also found that negative and positive ions (charged particles behaved in a different manner, days with negative overcharging were more frequent than days with positive overcharging.

The detection limits of antimicrobial agents in cow's milk by a simple Yoghurt Culture Test.

Science.gov (United States)

Mohsenzadeh, M; Bahrainipour, A

2008-09-15

The aim of this study was to study performance of Yoghurt Culture Test (YCT) in the detection of antimicrobial residues in milk. For this purpose, the sensitivity of YCT for 15 antibiotics were determined. For each drug, 8 concentrations were tested. The detection limits of YCT at 2.5 h and 4 h incubation were determined (microg kg(-1)): 15 and 37.5, penicillin G; 4 and 5, ampicillin; 5 and 7.5, amoxycillin; 100 and 200, cephalexin; 80 and 100, cefazoline; 100 and 200, oxytetracycline; 500 and 100, chlortetracycline; 100 and 200, tetracycline; 150 and 200, doxycycline; 200 and 400, sulphadimidine; 500 and 1000, gentamycin; 1000 and 1500, spectinomycin; 400 and 500, erythromycin; 50 and 100, tylosin; 5000 and 10000, chloramphenicol. The YCT detection limits at 2.5 h incubation for ampicillin, cephalexin, tetracycline, oxytetracycline and tylosin are similar to those obtained as Maximum Residue Limit (MRL) according to Regulation 2377/90 EEC as set out by the European Union. In addition the detection limits of YCT for some antibiotics were lower than some of microbial inhibitor test.

Photostimulated luminescence, fast method of detection of irradiated foodstuffs

International Nuclear Information System (INIS)

Guzik, G.P.; Stachowicz, W.

2005-01-01

The principle of pulsed photostimulated luminescence (PPSL) method, description of instrumentation and methodology of measurements are presented. The pathway of operational procedure and testing of the PPSL instrument in the Laboratory for Detection of Irradiated Food of the Institute of Nuclear Chemistry and Technology are described. Attention has been paid to the positives of the new method while some limitation of its application have been also discussed. (author)

Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency's prototype analysis

Science.gov (United States)

Culka, Adam; Osterrothová, Kateřina; Hutchinson, Ian; Ingley, Richard; McHugh, Melissa; Oren, Aharon; Edwards, Howell G. M.; Jehlička, Jan

2014-01-01

A prototype instrument, under development at the University of Leicester, for the future European Space Agency (ESA) ExoMars mission, was used for the analysis of microbial pigments within a stratified gypsum crust from a hypersaline saltern evaporation pond at Eilat (Israel). Additionally, the same samples were analysed using a miniaturized Raman spectrometer, featuring the same 532 nm excitation. The differences in the position of the specific bands, attributed to carotenoid pigments from different coloured layers, were minor when analysed by the ESA prototype instrument; therefore, making it difficult to distinguish among the different pigments. The portable Delta Nu Advantage instrument allowed for the discrimination of microbial carotenoids from the orange/green and purple layers. The purpose of this study was to complement previous laboratory results with new data and experience with portable or handheld Raman systems, even with a dedicated prototype Raman system for the exploration of Mars. The latter is equipped with an excitation wavelength falling within the carotenoid polyene resonance region. The ESA prototype Raman instrument detected the carotenoid pigments (biomarkers) with ease, although further detailed distinctions among them were not achieved. PMID:25368354

Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency's prototype analysis.

Science.gov (United States)

Culka, Adam; Osterrothová, Kateřina; Hutchinson, Ian; Ingley, Richard; McHugh, Melissa; Oren, Aharon; Edwards, Howell G M; Jehlička, Jan

2014-12-13

A prototype instrument, under development at the University of Leicester, for the future European Space Agency (ESA) ExoMars mission, was used for the analysis of microbial pigments within a stratified gypsum crust from a hypersaline saltern evaporation pond at Eilat (Israel). Additionally, the same samples were analysed using a miniaturized Raman spectrometer, featuring the same 532 nm excitation. The differences in the position of the specific bands, attributed to carotenoid pigments from different coloured layers, were minor when analysed by the ESA prototype instrument; therefore, making it difficult to distinguish among the different pigments. The portable Delta Nu Advantage instrument allowed for the discrimination of microbial carotenoids from the orange/green and purple layers. The purpose of this study was to complement previous laboratory results with new data and experience with portable or handheld Raman systems, even with a dedicated prototype Raman system for the exploration of Mars. The latter is equipped with an excitation wavelength falling within the carotenoid polyene resonance region. The ESA prototype Raman instrument detected the carotenoid pigments (biomarkers) with ease, although further detailed distinctions among them were not achieved. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Possible Detection of Perchlorates by the Sample Analysis at Mars (SAM) Instrument: Comparison with Previous Missions

Science.gov (United States)

Navarro-Gonzalex, Rafael; Sutter, Brad; Archer, Doug; Ming, Doug; Eigenbrode, Jennifer; Franz, Heather; Glavin, Daniel; McAdam, Amy; Stern, Jennifer; McKay, Christopher;

Limited interlaboratory comparison of Schmallenberg virus antibody detection in serum samples

DEFF Research Database (Denmark)

van der Poel, W. H. M.; Cay, B.; Zientara, S.

2014-01-01

Eight veterinary institutes in seven different countries in Europe participated in a limited interlaboratory comparison trial to evaluate laboratory performances of Schmallenberg virus (SBV) antibody detection in serum. Seven different sheep sera and three different cattle sera were circulated, a...

Detection limits for nanoparticles in solution with classical turbidity spectra

Science.gov (United States)

Le Blevennec, G.

2013-09-01

Detection of nanoparticles in solution is required to manage safety and environmental problems. Spectral transmission turbidity method has now been known for a long time. It is derived from the Mie Theory and can be applied to any number of spheres, randomly distributed and separated by large distance compared to wavelength. Here, we describe a method for determination of size, distribution and concentration of nanoparticles in solution using UV-Vis transmission measurements. The method combines Mie and Beer Lambert computation integrated in a best fit approximation. In a first step, a validation of the approach is completed on silver nanoparticles solution. Verification of results is realized with Transmission Electronic Microscopy measurements for size distribution and an Inductively Coupled Plasma Mass Spectrometry for concentration. In view of the good agreement obtained, a second step of work focuses on how to manage the concentration to be the most accurate on the size distribution. Those efficient conditions are determined by simple computation. As we are dealing with nanoparticles, one of the key points is to know what the size limits reachable are with that kind of approach based on classical electromagnetism. In taking into account the transmission spectrometer accuracy limit we determine for several types of materials, metals, dielectrics, semiconductors the particle size limit detectable by such a turbidity method. These surprising results are situated at the quantum physics frontier.

Improvement of detection limits of PIXE by substrate signal reduction

International Nuclear Information System (INIS)

Beaulieu, S.; Nejedly, Z.; Campbell, J.L.; Edwards, G.C.; Dias, G.M.

2002-01-01

Limits of detection (LODs) for aerosol samples collected using PIXE International cascade impactors, were improved approximately 50% after reducing the cross-sectional area of the analytical beam based on results obtained from microscope photographs of aerosol deposits. Improvements in LODs were most noticeable for selected elements collected on the smaller stages of the impactor (stages 1-3)

Fluctuation Scaling, Calibration of Dispersion, and Detection of Differences.

Science.gov (United States)

Holland, Rianne; Rebmann, Roman; Williams, Craig; Hanley, Quentin S

2017-11-07

Fluctuation scaling describes the relationship between the mean and standard deviation of a set of measurements. An example is Horwitz scaling, which has been reported from interlaboratory studies. Horwitz and similar studies have reported simple exponential and segmented scaling laws with exponents (α) typically between 0.85 (Horwitz) and 1 when not operating near a detection limit. When approaching a detection limit, the exponents change and approach an apparently Gaussian (α = 0) model. This behavior is often presented as a property of interlaboratory studies, which makes controlled replication to understand the behavior costly to perform. To assess the contribution of instrumentation to larger scale fluctuation scaling, we measured the behavior of two inductively coupled plasma atomic emission spectrometry (ICP-AES) systems, in two laboratories measuring thulium using two emission lines. The standard deviation universally increased with the uncalibrated signal, indicating the system was heteroscedastic. The response from all lines and both instruments was consistent with a single exponential dispersion model having parameters α = 1.09 and β = 0.0035. No evidence of Horwitz scaling was found, and there was no evidence of Poisson noise limiting behavior. The "Gaussian" component was a consequence of background subtraction for all lines and both instruments. The observation of a simple exponential dispersion model in the data allows for the definition of a difference detection limit (DDL) with universal applicability to systems following known dispersion. The DDL is the minimum separation between two points along a dispersion model required to claim they are different according to a particular statistical test. The DDL scales transparently with the mean and works at any location in a response function.

Calculation of the detection limits for radionuclides identified in gamma-ray spectra based on post-processing peak analysis results.

Science.gov (United States)

Korun, M; Vodenik, B; Zorko, B

2018-03-01

A new method for calculating the detection limits of gamma-ray spectrometry measurements is presented. The method is applicable for gamma-ray emitters, irrespective of the influences of the peaked background, the origin of the background and the overlap with other peaks. It offers the opportunity for multi-gamma-ray emitters to calculate the common detection limit, corresponding to more peaks. The detection limit is calculated by approximating the dependence of the uncertainty in the indication on its value with a second-order polynomial. In this approach the relation between the input quantities and the detection limit are described by an explicit expression and can be easy investigated. The detection limit is calculated from the data usually provided by the reports of peak-analyzing programs: the peak areas and their uncertainties. As a result, the need to use individual channel contents for calculating the detection limit is bypassed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Signal detection without finite-energy limits to quantum resolution

OpenAIRE

Luis Aina, Alfredo

2013-01-01

We show that there are extremely simple signal detection schemes where the finiteness of energy resources places no limit on the resolution. On the contrary, larger resolution can be obtained with lower energy. To this end the generator of the signal-dependent transformation encoding the signal information on the probe state must be different from the energy. We show that the larger the deviation of the probe state from being the minimum-uncertainty state, the better the resolution.

New generation low power radiation survey instruments

International Nuclear Information System (INIS)

Waechter, D.A.; Bjarke, G.O.; Trujillo, F.; Umbarger, C.J.; Wolf, M.A.

1984-01-01

A number of new, ultra-low-powered radiation instruments have recently been developed at Los Alamos. Among these are two instruments which use a novel power source to eliminate costly batteries. The newly developed gamma detecting radiac, nicknamed the Firefly, and the alpha particle detecting instrument, called the Simple Cordless Alpha Monitor, both use recent advances in miniaturization and powersaving electronics to yield devices which are small, rugged, and very power-frugal. The two instruments consume so little power that the need for batteries to run them is eliminated. They are, instead, powered by a charged capacitor which will operate the instruments for an hour or more. Use of a capacitor as a power source eliminates many problems commonly associated with battery-operated instruments, such as having to open the case to change batteries, battery storage life, availability of batteries in the field, and some savings in weight. Both line power and mechanical sources are used to charge the storage capacitors which power the instruments

In vitro bioassays for detecting dioxin-like activity--application potentials and limits of detection, a review.

Science.gov (United States)

Eichbaum, Kathrin; Brinkmann, Markus; Buchinger, Sebastian; Reifferscheid, Georg; Hecker, Markus; Giesy, John P; Engwall, Magnus; van Bavel, Bert; Hollert, Henner

2014-07-15

Use of in vitro assays as screening tool to characterize contamination of a variety of environmental matrices has become an increasingly popular and powerful toolbox in the field of environmental toxicology. While bioassays cannot entirely substitute analytical methods such as gas chromatography-mass spectrometry (GC-MS), the increasing improvement of cell lines and standardization of bioassay procedures enhance their utility as bioanalytical pre-screening tests prior to more targeted chemical analytical investigations. Dioxin-receptor-based assays provide a holistic characterization of exposure to dioxin-like compounds (DLCs) by integrating their overall toxic potential, including potentials of unknown DLCs not detectable via e.g. GC-MS. Hence, they provide important additional information with respect to environmental risk assessment of DLCs. This review summarizes different in vitro bioassay applications for detection of DLCs and considers the comparability of bioassay and chemical analytically derived toxicity equivalents (TEQs) of different approaches and various matrices. These range from complex samples such as sediments through single reference to compound mixtures. A summary of bioassay derived detection limits (LODs) showed a number of current bioassays to be equally sensitive as chemical methodologies, but moreover revealed that most of the bioanalytical studies conducted to date did not report their LODs, which represents a limitation with regard to low potency samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Method to Solve the Problem of the Radioactivity Detection in Environmental Samples. Characteristic Limits

International Nuclear Information System (INIS)

Gasco, C.; Martinez, M.; Heras, M.

2009-01-01

The problem of the detection or when the radioactivity can be considered as higher than the background using different measurement techniques has been the objective of several statistical studies and controversies. The detection limit and the critical limit were studied by Currie in year 1968 and used by radiochemistry laboratories considering different ways of calculation that introduced confusion and not correct implementations. In the last few years, and due to the increasing number of standardization processes on the field of radioactivity and accreditation, several international institutions have chosen to unify the criteria for using common determination of detection limits. The most used methods are those developed by MARLAP and International Standard Organization ISO (Standard-11929). In this report are summarised both standards doing a comparative study and giving some examples of how to apply these limits. In same cases, little differences in the uncertainty calculation have been observed but the final results have been concordant. A deeply study of these standards can be done consulting the web page of the American Labs that developed MARLAP or buying the original ISO standard ISO-11929 recently approved (2009). (Author) 17 refs

Predictive inference for best linear combination of biomarkers subject to limits of detection.

Science.gov (United States)

Coolen-Maturi, Tahani

2017-08-15

Measuring the accuracy of diagnostic tests is crucial in many application areas including medicine, machine learning and credit scoring. The receiver operating characteristic (ROC) curve is a useful tool to assess the ability of a diagnostic test to discriminate between two classes or groups. In practice, multiple diagnostic tests or biomarkers are combined to improve diagnostic accuracy. Often, biomarker measurements are undetectable either below or above the so-called limits of detection (LoD). In this paper, nonparametric predictive inference (NPI) for best linear combination of two or more biomarkers subject to limits of detection is presented. NPI is a frequentist statistical method that is explicitly aimed at using few modelling assumptions, enabled through the use of lower and upper probabilities to quantify uncertainty. The NPI lower and upper bounds for the ROC curve subject to limits of detection are derived, where the objective function to maximize is the area under the ROC curve. In addition, the paper discusses the effect of restriction on the linear combination's coefficients on the analysis. Examples are provided to illustrate the proposed method. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Spreadsheet design and validation for characteristic limits determination in gross alpha and beta measurement

International Nuclear Information System (INIS)

Prado, Rodrigo G.P. do; Dalmazio, Ilza

2013-01-01

The identification and detection of ionizing radiation are essential requisites of radiation protection. Gross alpha and beta measurements are widely applied as a screening method in radiological characterization, environmental monitoring and industrial applications. As in any other analytical technique, test performance depends on the quality of instrumental measurements and reliability of calculations. Characteristic limits refer to three specific statistics, namely, decision threshold, detection limit and confidence interval, which are fundamental to ensuring the quality of determinations. This work describes a way to calculate characteristic limits for measurements of gross alpha and beta activity applying spreadsheets. The approach used for determination of decision threshold, detection limit and limits of the confidence interval, the mathematical expressions of measurands and uncertainty followed standards guidelines. A succinct overview of this approach and examples are presented and spreadsheets were validated using specific software. Furthermore, these spreadsheets could be used as tool to instruct beginner users of methods for ionizing radiation measurements. (author)

A new LIF instrument for aircraft related and ground related masurements of OH and HO{sub 2} radicals in the troposphere; Ein neues LIF-Instrument fuer flugzeug- und bodengebundene Messungen von OH- und HO{sub 2}-Radikalen in der Troposphaere

Energy Technology Data Exchange (ETDEWEB)

Broch, Sebastian

2011-07-01

The author of the contribution under consideration describes the development and characterization of an instrument for the measurement of OH and HO{sub 2} radicals by means of laser-induced fluorescence (LIF). This instrument can be used from the lower troposphere to the lower stratosphere both on the ground and in aircraft applications. After describing the basics of the OH radical chemistry and the measurement principle of laser-induced fluorescence, a new instrument is presented. The LIF measuring cells needs long inlet pipes which lead to a modification of the verification of OH radicals. The effect of these modifications as well as the height dependence of the detection sensitivity for the OH radicals is examined. A model for the theoretical description of the altitude dependence of the detection sensitivity is described. The modification of the measuring cell influences the ozone-water interference in the LIF measurement system. Therefore, the author develops a model to describe the interference in the new system and evaluate this model by measurements. The applicability of this new instrument for ground and flight applications is analyzed in the range from 0 to 18 kilometers regarding sensitivity, detection limit and interference.

Decreasing of the detection limit for gamma-ray Spectrometry with the influence of sample treatment

International Nuclear Information System (INIS)

Karami, M.; Sadighzadeh, A.; Asgharizadeh, F.; Sardari, D.; Tavassoli, A.; Arbabi, A.; Hochaghani, O.

2009-01-01

Full text: In this study the ash method has been applied for environmental sample treatment in order to decrease of the detection limit in gamma-ray spectrometry for low level radioactivity measurements. Detection limit in gamma ray spectrometry is the smallest expectation value of the net counting rate that can be detected on given probabilities. The environmental test samples have been changed into ash using a suitable oven. The heating were made under controlled temperature to avoid the escape of some radionuclides such as radiocaesium. The ash samples were measured by high resolution gamma-ray spectrometry system. (author)

Instrumentation

International Nuclear Information System (INIS)

Umminger, K.

2008-01-01

A proper measurement of the relevant single and two-phase flow parameters is the basis for the understanding of many complex thermal-hydraulic processes. Reliable instrumentation is therefore necessary for the interaction between analysis and experiment especially in the field of nuclear safety research where postulated accident scenarios have to be simulated in experimental facilities and predicted by complex computer code systems. The so-called conventional instrumentation for the measurement of e. g. pressures, temperatures, pressure differences and single phase flow velocities is still a solid basis for the investigation and interpretation of many phenomena and especially for the understanding of the overall system behavior. Measurement data from such instrumentation still serves in many cases as a database for thermal-hydraulic system codes. However some special instrumentation such as online concentration measurement for boric acid in the water phase or for non-condensibles in steam atmosphere as well as flow visualization techniques were further developed and successfully applied during the recent years. Concerning the modeling needs for advanced thermal-hydraulic codes, significant advances have been accomplished in the last few years in the local instrumentation technology for two-phase flow by the application of new sensor techniques, optical or beam methods and electronic technology. This paper will give insight into the current state of instrumentation technology for safety-related thermohydraulic experiments. Advantages and limitations of some measurement processes and systems will be indicated as well as trends and possibilities for further development. Aspects of instrumentation in operating reactors will also be mentioned.

40 CFR Appendix B to Part 136 - Definition and Procedure for the Determination of the Method Detection Limit-Revision 1.11

Science.gov (United States)

2010-07-01

... calculated method detection limit. To insure that the estimate of the method detection limit is a good...) where: MDL = the method detection limit t(n-1,1- α=.99) = the students' t value appropriate for a 99... Determination of the Method Detection Limit-Revision 1.11 B Appendix B to Part 136 Protection of Environment...

Limits of detection of americium-241 in air

International Nuclear Information System (INIS)

Bereznai, T.

1995-01-01

Seven semiconductor detectors with various characteristics (type, form, size, etc.) were tested and compared in gamma-spectrometric assays for Am-241 aerosols in air. The problem at hand (determining a low activity or attaining a set detection limit (approx. 2 mBq/m 3 ) as soon as possible after sampling) was solved best by a large-volume n-type detector with a Be-window. In addition to the detector parameters commonly used (energy resolution and effectiveness), the peak-to-background ratio and the background counting rate at the gamma-energy of the nuclide to be determined are important criteria influencing the choice of equipment. (orig.) [de

Some practical applications of an ICP-MS instrument

International Nuclear Information System (INIS)

Meddings, B.; Ng, R.

1987-01-01

An early model commercial ICP-MS instrument (PlasmaQuad from VG Isotopes Limited) was acquired more than two years ago. As a typical analytical laboratory in the metallurgical field, the application of the ICP-MS technique to real sample analysis is the authors prime concern. The process of introducing this state-of-the-art instrument into routine analysis will be described. The modifications and limitations necessary to achieve acceptable precision under normal working conditions will be outlined. In most cases, practical problems can be circumvented with some sacrifice in analytical performance in the area of detection limits and dynamic range. In this presentation, specific applications of the ICP-MS technique in the authors laboratory will be discussed. These include trace analysis on high purity metals such as copper, aluminum, cobalt, nickel etc., on refinery feed samples such as nickel sulfate, mixed cobalt and nickel sulfide, cobalt cathode, samarium oxide etc., on alloys such as cobalt-samarium magnetic materials, nickel or cobalt based alloys used in turbine blades etc. Other applications such as the determination of uranium in phosphate rock, trace analysis on fertilizers, water samples and high purity acids will also be mentioned. The solutions to the practical problems encountered in these applications will be discussed. The analytical power of the ICP-MS technique for real sample analysis will be assessed

Design and implementation of quench detection instrumentation for TF magnet system of SST-1

International Nuclear Information System (INIS)

Khristi, Y.; Sharma, A.N.; Doshi, K.; Banaudha, M.; Prasad, U.; Varmora, P.; Patel, D.; Pradhan, S.

2014-01-01

Steady State Superconducting Tokamak-1 (SST-1) at Institute for Plasma Research (IPR), India is now in engineering validation phase. The assembled Toroidal Field (TF) magnet system of SST-1 will be operated at 10 kA of nominal current at helium cooled condition of 4.5 K. A reliable and fail proof quench detection (QD) system is essential for the safety and the investment protection requirements of the magnets. This QD system needs to continuously monitor all the superconducting coils, which include 16 TF magnets, return-loop, bus bars and current leads. In case of any event initiating the normal resistive zone and reaching thermal run-away, the QD system needs to trigger the magnet protection circuits. Precision instrumentation and control system with 204 signal channels had been developed for detection of quench anywhere in the entire TF magnet system. In the present configuration of quench detection scheme, the voltage drop across each double pancake (DP) of each TF coil are compared with its two adjacent DPs for the detection of normal zone and cancelation of inductive couples. Two identical redundant systems with one out of two configurations are successfully commissioned and tested at IPR. This paper describes the design and implementation of the QD system, Installation experience, validation test and initial results from the recent SST-1 magnet system charging

Endoscopic vision-based tracking of multiple surgical instruments during robot-assisted surgery.

Science.gov (United States)

Ryu, Jiwon; Choi, Jaesoon; Kim, Hee Chan

2013-01-01

Robot-assisted minimally invasive surgery is effective for operations in limited space. Enhancing safety based on automatic tracking of surgical instrument position to prevent inadvertent harmful events such as tissue perforation or instrument collisions could be a meaningful augmentation to current robotic surgical systems. A vision-based instrument tracking scheme as a core algorithm to implement such functions was developed in this study. An automatic tracking scheme is proposed as a chain of computer vision techniques, including classification of metallic properties using k-means clustering and instrument movement tracking using similarity measures, Euclidean distance calculations, and a Kalman filter algorithm. The implemented system showed satisfactory performance in tests using actual robot-assisted surgery videos. Trajectory comparisons of automatically detected data and ground truth data obtained by manually locating the center of mass of each instrument were used to quantitatively validate the system. Instruments and collisions could be well tracked through the proposed methods. The developed collision warning system could provide valuable information to clinicians for safer procedures. © 2012, Copyright the Authors. Artificial Organs © 2012, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Amperometric Sensor for Detection of Chloride Ions†

Science.gov (United States)

Trnkova, Libuse; Adam, Vojtech; Hubalek, Jaromir; Babula, Petr; Kizek, Rene

2008-01-01

Chloride ion sensing is important in many fields such as clinical diagnosis, environmental monitoring and industrial applications. We have measured chloride ions at a carbon paste electrode (CPE) and at a CPE modified with solid AgNO3, a solution of AgNO3 and/or solid silver particles. Detection limits (3 S/N) for chloride ions were 100 μM, 100 μM and 10 μM for solid AgNO3, solution of AgNO3 and/or solid silver particles, respectively. The CPE modified with silver particles is the most sensitive to the presence chloride ions. After that we approached to the miniaturization of the whole electrochemical instrument. Measurements were carried out on miniaturized instrument consisting of a potentiostat with dimensions 35 × 166 × 125 mm, screen printed electrodes, a peristaltic pump and a PC with control software. Under the most suitable experimental conditions (Britton-Robinson buffer, pH 1.8 and working electrode potential 550 mV) we estimated the limit of detection (3 S/N) as 500 nM. PMID:27873832

Amperometric Sensor for Detection of Chloride Ions.

Science.gov (United States)

Trnkova, Libuse; Adam, Vojtech; Hubalek, Jaromir; Babula, Petr; Kizek, Rene

2008-09-15

Chloride ion sensing is important in many fields such as clinical diagnosis, environmental monitoring and industrial applications. We have measured chloride ions at a carbon paste electrode (CPE) and at a CPE modified with solid AgNO₃, a solution of AgNO₃ and/or solid silver particles. Detection limits (3 S/N) for chloride ions were 100 μM, 100 μM and 10 μM for solid AgNO₃, solution of AgNO₃ and/or solid silver particles, respectively. The CPE modified with silver particles is the most sensitive to the presence chloride ions. After that we approached to the miniaturization of the whole electrochemical instrument. Measurements were carried out on miniaturized instrument consisting of a potentiostat with dimensions 35 × 166 × 125 mm, screen printed electrodes, a peristaltic pump and a PC with control software. Under the most suitable experimental conditions (Britton-Robinson buffer, pH 1.8 and working electrode potential 550 mV) we estimated the limit of detection (3 S/N) as 500 nM.

Instrument uncertainty predictions

International Nuclear Information System (INIS)

Coutts, D.A.

1991-07-01

The accuracy of measurements and correlations should normally be provided for most experimental activities. The uncertainty is a measure of the accuracy of a stated value or equation. The uncertainty term reflects a combination of instrument errors, modeling limitations, and phenomena understanding deficiencies. This report provides several methodologies to estimate an instrument's uncertainty when used in experimental work. Methods are shown to predict both the pretest and post-test uncertainty

The limitations on organic detection in Mars-like soils by thermal volatilization-gas chromatography-MS and their implications for the Viking results.

Science.gov (United States)

Navarro-González, Rafael; Navarro, Karina F; de la Rosa, José; Iñiguez, Enrique; Molina, Paola; Miranda, Luis D; Morales, Pedro; Cienfuegos, Edith; Coll, Patrice; Raulin, François; Amils, Ricardo; McKay, Christopher P

2006-10-31

The failure of Viking Lander thermal volatilization (TV) (without or with thermal degradation)-gas chromatography (GC)-MS experiments to detect organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV-GC-MS may be blind to low levels of organics on Mars. A comparison between TV-GC-MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10-90 mug of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO(2)) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50-700 ppm of CO(2) by TV-GC-MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV-GC-MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life.

The limitations on organic detection in Mars-like soils by thermal volatilization–gas chromatography–MS and their implications for the Viking results

Science.gov (United States)

Navarro-González, Rafael; Navarro, Karina F.; de la Rosa, José; Iñiguez, Enrique; Molina, Paola; Miranda, Luis D.; Morales, Pedro; Cienfuegos, Edith; Coll, Patrice; Raulin, François; Amils, Ricardo; McKay, Christopher P.

2006-01-01

The failure of Viking Lander thermal volatilization (TV) (without or with thermal degradation)–gas chromatography (GC)–MS experiments to detect organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV–GC–MS may be blind to low levels of organics on Mars. A comparison between TV–GC–MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10–90 μg of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV–GC–MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO2) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50–700 ppm of CO2 by TV–GC–MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV–GC–MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life. PMID:17060639

Detection and grading of dAVF: prospects and limitations of 3T MRI.

Science.gov (United States)

Bink, Andrea; Berkefeld, Joachim; Wagner, Marlies; You, Se-Jong; Ackermann, Hanns; Lorenz, Matthias W; Senft, Christian; du Mesnil de Rochemont, Richard

2012-02-01

DSA is currently the criterion standard for the assessment of dural arteriovenous fistulas (dAVF). Recently, evolving MRA techniques have emerged as a non-invasive alternative. The aim of this study is to assess the value of 3 T MRI in detecting and describing dAVF and to determine whether MRI can replace DSA as diagnostic procedure. A total of 19 patients with dAVF and 19 without dAVF underwent the same MRI protocol, including 3D time-of-flight MRA and time-resolved contrast-enhanced MRA. The images were evaluated retrospectively by three independent readers with different levels of experience blinded to clinical information. The readers assessed the presence, the site, the venous drainage and the feeders of dAVF. Sensitivity, specificity, accuracy, intertechnique and interobserver agreements were calculated. DAVF can be detected with high sensitivity, specificity and accuracy by experienced and also by less experienced readers. However, MRI has limitations when used for grading and evaluation of the angioarchitecture of the dAVF. Different experience, the limited resolution of MRI and its inability to selectively display arteries were the reasons for these limitations. With MRI dAVF can be detected reliably. Nevertheless, at present MRI can not fully replace DSA, especially for treatment planning.

Intelligent type sodium instrumentations for LMFBR

International Nuclear Information System (INIS)

Chen Daolong

1996-07-01

The constructions and performances of lots of newly developed intelligent type sodium instrumentations are described. The graduation characteristic equations for corresponding transducer using the medium temperature as the parameter are given. These intelligent type sodium instrumentations are possessed of good linearity. The accurate measurement data of sodium process parameters (flowrate, pressure and level) can be obtained by means of their on-line compensation function of the temperature effect. Moreover, these intelligent type sodium instrumentations are possessed of the self-inspection, the electric shutoff protection, the setting of full-scale, the setting of alarm limits (two upper limits and two lower limits alarms), the thermocouple breaking alarm, mutual isolative the 0∼10 V direct-current analogue output and the CENTRONICS standard digital output, and the alarm relay contact output. Theses intelligent type sodium instrumentations are suitable particularly for the instrument, control and protective systems of LMFBR by means of these excellent functions based on microprocessor. The basic errors of the intelligent type sodium flowmeter, immersed sodium flowmeter, sodium manometer and sodium level gauge are +-2%, +-2.3%, +-0.3% and +-1.9% of measuring ranges respectively. (9 figs.)

Weather Instruments.

Science.gov (United States)

Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

This booklet presents some activities to measure various weather phenomena. Directions for constructing a weather station are included. Instruments including rain gauges, thermometers, wind vanes, wind speed devices, humidity devices, barometers, atmospheric observations, a dustfall jar, sticky-tape can, detection of gases in the air, and pH of…

Bayesian-statistical decision threshold, detection limit, and confidence interval in nuclear radiation measurement

International Nuclear Information System (INIS)

Weise, K.

1998-01-01

When a contribution of a particular nuclear radiation is to be detected, for instance, a spectral line of interest for some purpose of radiation protection, and quantities and their uncertainties must be taken into account which, such as influence quantities, cannot be determined by repeated measurements or by counting nuclear radiation events, then conventional statistics of event frequencies is not sufficient for defining the decision threshold, the detection limit, and the limits of a confidence interval. These characteristic limits are therefore redefined on the basis of Bayesian statistics for a wider applicability and in such a way that the usual practice remains as far as possible unaffected. The principle of maximum entropy is applied to establish probability distributions from available information. Quantiles of these distributions are used for defining the characteristic limits. But such a distribution must not be interpreted as a distribution of event frequencies such as the Poisson distribution. It rather expresses the actual state of incomplete knowledge of a physical quantity. The different definitions and interpretations and their quantitative consequences are presented and discussed with two examples. The new approach provides a theoretical basis for the DIN 25482-10 standard presently in preparation for general applications of the characteristic limits. (orig.) [de

DOE Fundamentals Handbook: Instrumentation and Control, Volume 1

International Nuclear Information System (INIS)

1992-06-01

The Instrumentation and Control Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of instrumentation and control systems. The handbook includes information on temperature, pressure, flow, and level detection systems; position indication systems; process control systems; and radiation detection principles. This information will provide personnel with an understanding of the basic operation of various types of DOE nuclear facility instrumentation and control systems

DOE Fundamentals Handbook: Instrumentation and Control, Volume 1

Energy Technology Data Exchange (ETDEWEB)

1992-06-01

The Instrumentation and Control Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of instrumentation and control systems. The handbook includes information on temperature, pressure, flow, and level detection systems; position indication systems; process control systems; and radiation detection principles. This information will provide personnel with an understanding of the basic operation of various types of DOE nuclear facility instrumentation and control systems.

DOE Fundamentals Handbook: Instrumentation and Control, Volume 2

International Nuclear Information System (INIS)

1992-06-01

The Instrumentation and Control Fundamentals Handbook personnel, and the technical staff facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of instrumentation and control systems. The handbook includes information on temperature, pressure, flow, and level detection systems; position indication systems; process control systems; and radiation detection principles. This information will provide personnel with an understanding of the basic operation of various types of DOE nuclear facility instrumentation and control systems

LANSCE beam current limiter

International Nuclear Information System (INIS)

Gallegos, F.R.

1996-01-01

The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

Field-portable high-resolution EDXRF analysis with HgI2-detector-based instrumentation

International Nuclear Information System (INIS)

Berry, P.F.; Little, S.R.; Voots, G.R.

1992-01-01

Energy dispersive x-ray fluorescence (EDXRF) analysis is well known for its efficient use of x-ray detector technology for simultaneous multielement determination. Low-intensity excitation, such as from a radioisotope source, can thus be employed and has enabled the design of many types of truly portable EDXRF instrumentation. Portable design, however, has not been without significant compromise in analytical performance because of the limited x-ray resolving power of prior detection methods, except by the use of a cryogenically operated detector. The developments we refer to stem from the use of a comparatively new x-ray detection device fabricated from mercuric iodide (HgI 2 ). For this detector, only a modest degree of cooling is required to achieve an energy resolution of > 300 eV. Two field-portable instrument designs of different hand-held measurement probe configurations are available that have applications for industrial quality assurance and environmental screening

Instrumentation

International Nuclear Information System (INIS)

Muehllehner, G.; Colsher, J.G.

1982-01-01

This chapter reviews the parameters which are important to positron-imaging instruments. It summarizes the options which various groups have explored in designing tomographs and the methods which have been developed to overcome some of the limitations inherent in the technique as well as in present instruments. The chapter is not presented as a defense of positron imaging versus single-photon or other imaging modality, neither does it contain a description of various existing instruments, but rather stresses their common properties and problems. Design parameters which are considered are resolution, sampling requirements, sensitivity, methods of eliminating scattered radiation, random coincidences and attenuation. The implementation of these parameters is considered, with special reference to sampling, choice of detector material, detector ring diameter and shielding and variations in point spread function. Quantitation problems discussed are normalization, and attenuation and random corrections. Present developments mentioned are noise reduction through time-of-flight-assisted tomography and signal to noise improvements through high intrinsic resolution. Extensive bibliography. (U.K.)

Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging.

Directory of Open Access Journals (Sweden)

Alexander J Taylor

Full Text Available Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration. An experimental "calibration factor" to account for variations in coil configuration and hardware set-up is specified. Once it has been determined in a calibration experiment, the sensitivity of an experiment or, alternatively, the minimum number of required spins or the minimum marker concentration can be estimated without the need for a pilot experiment. The definition of this calibration factor is derived based on standard equations for the sensitivity in magnetic resonance, yet the method is not restricted by the limited validity of these equations, since additional instrument-dependent factors are implicitly included during calibration. The method is demonstrated using MR spectroscopy and imaging experiments with different 19F samples, both paramagnetically and susceptibility broadened, to approximate a range of realistic environments.

Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging.

Science.gov (United States)

Taylor, Alexander J; Granwehr, Josef; Lesbats, Clémentine; Krupa, James L; Six, Joseph S; Pavlovskaya, Galina E; Thomas, Neil R; Auer, Dorothee P; Meersmann, Thomas; Faas, Henryk M

2016-01-01

Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI) using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration. An experimental "calibration factor" to account for variations in coil configuration and hardware set-up is specified. Once it has been determined in a calibration experiment, the sensitivity of an experiment or, alternatively, the minimum number of required spins or the minimum marker concentration can be estimated without the need for a pilot experiment. The definition of this calibration factor is derived based on standard equations for the sensitivity in magnetic resonance, yet the method is not restricted by the limited validity of these equations, since additional instrument-dependent factors are implicitly included during calibration. The method is demonstrated using MR spectroscopy and imaging experiments with different 19F samples, both paramagnetically and susceptibility broadened, to approximate a range of realistic environments.

Upper limits from counting experiments with multiple pipelines

International Nuclear Information System (INIS)

Sutton, Patrick J

2009-01-01

In counting experiments, one can set an upper limit on the rate of a Poisson process based on a count of the number of events observed due to the process. In some experiments, one makes several counts of the number of events, using different instruments, different event detection algorithms or observations over multiple time intervals. We demonstrate how to generalize the classical frequentist upper limit calculation to the case where multiple counts of events are made over one or more time intervals using several (not necessarily independent) procedures. We show how different choices of the rank ordering of possible outcomes in the space of counts correspond to applying different levels of significance to the various measurements. We propose an ordering that is matched to the sensitivity of the different measurement procedures and show that in typical cases it gives stronger upper limits than other choices. As an example, we show how this method can be applied to searches for gravitational-wave bursts, where multiple burst-detection algorithms analyse the same data set, and demonstrate how a single combined upper limit can be set on the gravitational-wave burst rate.

Gravitational wave detection using laser interferometry beyond the standard quantum limit

Science.gov (United States)

Heurs, M.

2018-05-01

Interferometric gravitational wave detectors (such as advanced LIGO) employ high-power solid-state lasers to maximize their detection sensitivity and hence their reach into the universe. These sophisticated light sources are ultra-stabilized with regard to output power, emission frequency and beam geometry; this is crucial to obtain low detector noise. However, even when all laser noise is reduced as far as technically possible, unavoidable quantum noise of the laser still remains. This is a consequence of the Heisenberg Uncertainty Principle, the basis of quantum mechanics: in this case, it is fundamentally impossible to simultaneously reduce both the phase noise and the amplitude noise of a laser to arbitrarily low levels. This fact manifests in the detector noise budget as two distinct noise sources-photon shot noise and quantum radiation pressure noise-which together form a lower boundary for current-day gravitational wave detector sensitivities, the standard quantum limit of interferometry. To overcome this limit, various techniques are being proposed, among them different uses of non-classical light and alternative interferometer topologies. This article explains how quantum noise enters and manifests in an interferometric gravitational wave detector, and gives an overview of some of the schemes proposed to overcome this seemingly fundamental limitation, all aimed at the goal of higher gravitational wave event detection rates. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis.

Science.gov (United States)

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Liu, Zheng; Zhang, Yupeng

2015-01-01

The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation. The mean follow-up was 36.9 months (range: 24-62 months). The kyphotic angle ranged from 15.2-35.1° preoperatively, with an average measurement of 27.8°. The American Spinal Injury Association (ASIA) score system was used to evaluate the neurological deficits and erythrocyte sedimentation rate (ESR) used to judge the activity of TB. Spinal TB was completely cured in all 17 patients. There was no recurrent TB infection. The postoperative kyphotic angle was 6.6-10.2°, 8.1° in average, and there was no significant loss of the correction at final follow-up. Solid fusion was achieved in all cases. Neurological condition in all patients was improved after surgery. Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation can be a feasible and effective method the in treatment of single-segment lumbar spinal TB.

Fiber optic FTIR instrument for in vivo detection of colonic neoplasia

Science.gov (United States)

Van Nortwick, Matthew; Hargrove, John; Wolters, Rolf; Crawford, James M.; Arroyo, May; Mackanos, Mark; Contag, Christopher H.; Wang, Thomas D.

2009-02-01

We demonstrate the proof of concept for use of a fiber optic FTIR instrument to perform in vivo detection of colonic neoplasia as an adjunct to medical endoscopy. FTIR is sensitive to the molecular composition of tissue, and can be used as a guide for biopsy by identifying pre-malignant tissue (dysplasia). First, we demonstrate the use of a silver halide optical fiber to collect mid-infrared absorption spectra in the 950 to 1800 cm-1 regime with high signal-to-noise from biopsy specimens of colonic mucosa tissue ex vivo. We observed subtle differences in wavenumber and magnitude of the absorbance peaks over this regime. We then show that optimal sub-ranges can be defined within this spectral regime and that spectral pre-processing can be performed to classify the tissue as normal, hyperplasia, or dysplasia with high levels of performance. We used a partial least squares discriminant analysis and a leave-one-subject-out crossvalidation strategy to classify the spectra. The results were compared with histology, and the optimal thresholds resulted in an overall sensitivity, specificity, accuracy, and positive predictive value of 96%, 92%, 93%, and 82%, respectively for this technique. We demonstrate that mid-infrared absorption spectra can be collected remotely with an optical fiber and used to identify colonic dysplasia with high accuracy. We are now developing an endoscope compatible optical fiber to use this technique clinically for the early detection of cancer.

Spectral Aerosol Extinction (SpEx): A New Instrument for In situ Ambient Aerosol Extinction Measurements Across the UV/Visible Wavelength Range

Science.gov (United States)

Jordan, C. E.; Anderson, B. E.; Beyersdorf, A. J.; Corr, C. A.; Dibb, J. E.; Greenslade, M. E.; Martin, R. F.; Moore, R. H.; Scheuer, E.; Shook, M. A.;

Upper limit set for level of lightning activity on Titan

Science.gov (United States)

Desch, M. D.; Kaiser, M. L.

1990-01-01

Because optically thick cloud and haze layers prevent lightning detection at optical wavelength on Titan, a search was conducted for lightning-radiated signals (spherics) at radio wavelengths using the planetary radioastronomy instrument aboard Voyager 1. Given the maximum ionosphere density of about 3000/cu cm, lightning spherics should be detectable above an observing frequency of 500 kHz. Since no evidence for spherics is found, an upper limit to the total energy per flash in Titan lightning of about 10 to the 6th J, or about 1000 times weaker than that of typical terrestrial lightning, is inferred.

Improved Instrument for Detecting Water and Ice in Soil

Science.gov (United States)

Buehler, Martin; Chin, Keith; Keymeulen, Didler; McCann, Timothy; Seshadri, Suesh; Anderson, Robert

2009-01-01

An instrument measures electrical properties of relatively dry soils to determine their liquid water and/or ice contents. Designed as a prototype of instruments for measuring the liquid-water and ice contents of lunar and planetary soils, the apparatus could also be utilized for similar purposes in research and agriculture involving terrestrial desert soils and sands, and perhaps for measuring ice buildup on aircraft surfaces. This instrument is an improved version of the apparatus described in Measuring Low Concentrations of Liquid Water and Ice in Soil (NPO-41822), NASA Tech Briefs, Vol. 33, No. 2 (February 2009), page 22. The designs of both versions are based on the fact that the electrical behavior of a typical soil sample is well approximated by a network of resistors and capacitors in which resistances decrease and capacitances increase (and the magnitude and phase angle of impedance changes accordingly) with increasing water content. The previous version included an impedance spectrometer and a jar into which a sample of soil was placed. Four stainless-steel screws at the bottom of the jar were used as electrodes of a fourpoint impedance probe connected to the spectrometer. The present instrument does not include a sample jar and can be operated without acquiring or handling samples. Its impedance probe consists of a compact assembly of electrodes housed near the tip of a cylinder. The electrodes protrude slightly from the cylinder (see Figure 1). In preparation for measurements, the cylinder is simply pushed into the ground to bring the soil into contact with the electrodes.

Digital Holographic Microscopy, a Method for Detection of Microorganisms in Plume Samples from Enceladus and Other Icy Worlds.

Science.gov (United States)

Bedrossian, Manuel; Lindensmith, Chris; Nadeau, Jay L

2017-09-01

Detection of extant microbial life on Earth and elsewhere in the Solar System requires the ability to identify and enumerate micrometer-scale, essentially featureless cells. On Earth, bacteria are usually enumerated by culture plating or epifluorescence microscopy. Culture plates require long incubation times and can only count culturable strains, and epifluorescence microscopy requires extensive staining and concentration of the sample and instrumentation that is not readily miniaturized for space. Digital holographic microscopy (DHM) represents an alternative technique with no moving parts and higher throughput than traditional microscopy, making it potentially useful in space for detection of extant microorganisms provided that sufficient numbers of cells can be collected. Because sample collection is expected to be the limiting factor for space missions, especially to outer planets, it is important to quantify the limits of detection of any proposed technique for extant life detection. Here we use both laboratory and field samples to measure the limits of detection of an off-axis digital holographic microscope (DHM). A statistical model is used to estimate any instrument's probability of detection at various bacterial concentrations based on the optical performance characteristics of the instrument, as well as estimate the confidence interval of detection. This statistical model agrees well with the limit of detection of 10 3 cells/mL that was found experimentally with laboratory samples. In environmental samples, active cells were immediately evident at concentrations of 10 4 cells/mL. Published estimates of cell densities for Enceladus plumes yield up to 10 4 cells/mL, which are well within the off-axis DHM's limits of detection to confidence intervals greater than or equal to 95%, assuming sufficient sample volumes can be collected. The quantitative phase imaging provided by DHM allowed minerals to be distinguished from cells. Off-axis DHM's ability for

Advances in Miniaturized Instruments for Genomics

Directory of Open Access Journals (Sweden)

Cihun-Siyong Alex Gong

2014-01-01

Full Text Available In recent years, a lot of demonstrations of the miniaturized instruments were reported for genomic applications. They provided the advantages of miniaturization, automation, sensitivity, and specificity for the development of point-of-care diagnostics. The aim of this paper is to report on recent developments on miniaturized instruments for genomic applications. Based on the mature development of microfabrication, microfluidic systems have been demonstrated for various genomic detections. Since one of the objectives of miniaturized instruments is for the development of point-of-care device, impedimetric detection is found to be a promising technique for this purpose. An in-depth discussion of the impedimetric circuits and systems will be included to provide total consideration of the miniaturized instruments and their potential application towards real-time portable imaging in the “-omics” era. The current excellent demonstrations suggest a solid foundation for the development of practical and widespread point-of-care genomic diagnostic devices.

Using new financial instruments for improving oil trade across Africa: opportunities and limits

International Nuclear Information System (INIS)

Rutten, L.

2001-01-01

This brief paper discusses the potential for using new financial instruments for two purposes: improving intra-African oil trade; and improving the management of the financial flows that come with oil imports and exports. Although different, there are two significant similarities between these two issues. Firstly, the new financial instruments that can be used share some characteristics, and are often arranged/provided by one and the same department in trading companies and banks; they are often used together. Second, in both cases, the key problem that these financial instruments are meant to solve is that of risk. In one case, counterparty risk, in the other, price risk. (au)

Aiming for the theoretical limit of sensitivity of Bonse-Hart USANS instruments

International Nuclear Information System (INIS)

Carpenter, John M; Agamalian, Michael

2010-01-01

.9. Therefore, the Cd shielding of the triple-bounce crystal becomes ineffective and the parasitic single-bounce back-face reflection and TDS, blocked for 0.5 < λ < 3.0 A, reappear for λ< 0.5 A. It is practically impossible to separate this parasitic scattering from the triple-bounce reflection at steady state neutron beam lines except by the use of highly curved neutron guides. However, the TOF-USANS instrument, which is currently under construction at SNS, allows separation of the orders of Bragg reflections and the residual TDS in time-of-flight and thus the discovered parasitic effect cannot compromise its sensitivity. Thus, we expect to approach the theoretical limit of sensitivity for the SNS TOF-USANS instrument.

Telephone-based screening tools for mild cognitive impairment and dementia in aging studies: a review of validated instruments

Directory of Open Access Journals (Sweden)

Teresa Costa Castanho

2014-02-01

Full Text Available The decline of cognitive function in old age is a great challenge for modern society. The simultaneous increase in dementia and other neurodegenerative diseases justifies a growing need for accurate and valid cognitive assessment instruments. Although in-person testing is considered the most effective and preferred administration mode of assessment, it can pose not only a research difficulty in reaching large and diverse population samples, but it may also limit the assessment and follow-up of individuals with either physical or health limitations or reduced motivation. Therefore, telephone-based cognitive screening instruments pose an alternative and attractive strategy to in-person assessments. In order to give a current view of the state of the art of telephone-based tools for cognitive assessment in aging, this review highlights some of the existing instruments with particular focus on data validation, cognitive domains assessed, administration time and instrument limitations and advantages. From the review of the literature, performed using the databases EBSCO, Science Direct and PubMed, it was possible to verify that while telephone-based tools are useful in research and clinical practice, providing a promising approach, the methodologies still need refinement in the validation steps, including comparison with either single instruments or neurocognitive test batteries, to improve specificity and sensitivity to validly detect subtle changes in cognition that may precede cognitive impairment.

Investigation of a gamma sensitive Ge-detector with Marinelligeometry. Determination of the detection limits

International Nuclear Information System (INIS)

Moricz, P.

1984-01-01

Different Marinelli geometries have been compared with a 180 ml standard plastic breaker geometry as a reference. The results show that the Marinelli geometries are the best. E.g. the detection limit with a Marinelli geometry of 0.5 l is only half compared with the limit when the standard geometry is used. (Edv)

Radiation transmission type pipe wall thinning detection device and measuring instruments utilizing ionizing radiation

International Nuclear Information System (INIS)

Higashi, Yasuhiko

2009-01-01

We developed the device to detect thinning of pipe thorough heat insulation in Power Plant, etc, even while the plant is under operation. It is necessary to test many parts of many pipes for pipe wall thinning management, but it is difficult within a limited time of the routine test. This device consists of detector and radiation source, which can detect the pipe (less than 500 mm in external diameter, less than 50 mm in thickness) with 1.6%-reproducibility (in a few-minutes measurement), based on the attenuation rate. Operation is easy and effective without removing the heat insulation. We will expand this thinning detection system, and contribute the safety of the Plant. (author)

Supervised detection of exoplanets in high-contrast imaging sequences

Science.gov (United States)

Gomez Gonzalez, C. A.; Absil, O.; Van Droogenbroeck, M.

2018-06-01

Context. Post-processing algorithms play a key role in pushing the detection limits of high-contrast imaging (HCI) instruments. State-of-the-art image processing approaches for HCI enable the production of science-ready images relying on unsupervised learning techniques, such as low-rank approximations, for generating a model point spread function (PSF) and subtracting the residual starlight and speckle noise. Aims: In order to maximize the detection rate of HCI instruments and survey campaigns, advanced algorithms with higher sensitivities to faint companions are needed, especially for the speckle-dominated innermost region of the images. Methods: We propose a reformulation of the exoplanet detection task (for ADI sequences) that builds on well-established machine learning techniques to take HCI post-processing from an unsupervised to a supervised learning context. In this new framework, we present algorithmic solutions using two different discriminative models: SODIRF (random forests) and SODINN (neural networks). We test these algorithms on real ADI datasets from VLT/NACO and VLT/SPHERE HCI instruments. We then assess their performances by injecting fake companions and using receiver operating characteristic analysis. This is done in comparison with state-of-the-art ADI algorithms, such as ADI principal component analysis (ADI-PCA). Results: This study shows the improved sensitivity versus specificity trade-off of the proposed supervised detection approach. At the diffraction limit, SODINN improves the true positive rate by a factor ranging from 2 to 10 (depending on the dataset and angular separation) with respect to ADI-PCA when working at the same false-positive level. Conclusions: The proposed supervised detection framework outperforms state-of-the-art techniques in the task of discriminating planet signal from speckles. In addition, it offers the possibility of re-processing existing HCI databases to maximize their scientific return and potentially improve

Beam-limiting and radiation-limiting interlocks

International Nuclear Information System (INIS)

Macek, R.J.

1996-01-01

This paper reviews several aspects of beam-limiting and radiation- limiting interlocks used for personnel protection at high-intensity accelerators. It is based heavily on the experience at the Los Alamos Neutron Science Center (LANSCE) where instrumentation-based protection is used extensively. Topics include the need for ''active'' protection systems, system requirements, design criteria, and means of achieving and assessing acceptable reliability. The experience with several specific devices (ion chamber-based beam loss interlock, beam current limiter interlock, and neutron radiation interlock) designed and/or deployed to these requirements and criteria is evaluated

Intelligent type sodium instrumentations for LMFR

International Nuclear Information System (INIS)

Daolong Chen

1996-01-01

The constructions and their performances of a lot of newly developed intelligent type sodium instrumentations that consist of the intelligent type sodium flowmeter, the intelligent type immersed sodium flowmeter, the intelligent type sodium manometer and the intelligent type sodium level gauge are described. The graduation characteristic equations for corresponding transducer using the medium temperature as the parameter are given. Because the operating temperature limit of measured medium (sodium) is wide, so the on-line compensation of the temperature effect of their graduation characteristics much be considered. The tests show that these intelligent type sodium instrumentations possess of good linearity. The accurate sodium process parameter (flowrate, pressure and level) measurement data can be obtained by means of their on-line compensation function of the temperature effect. Moreover, these intelligent type sodium instrumentations possess of the self-inspection, the electric shutoff protection, the setting of full-scale, the setting of alarm limits (two upper limits and two lower limits alarms), the thermocouple breaking alarm, each other isolative the 0-10V direct-current analogue output and CENTRONICS standard digital output, and the alarm relay contact output. These intelligent type sodium instrumentations are suitable particularly for the instrument, control and protective systems of LMFR by means of these excellent functions based on microprocessor. The basic error of the intelligent type sodium flowmeter, immersed sodium flowmeter, sodium manometer and sodium level gauge is respectively ±2%, ±2.3%, ±0.3% and ±1.9% of measuring range. (author). 4 refs, 9 figs

Trace element analysis by EPMA in geosciences: detection limit, precision and accuracy

Science.gov (United States)

Batanova, V. G.; Sobolev, A. V.; Magnin, V.

2018-01-01

Use of the electron probe microanalyser (EPMA) for trace element analysis has increased over the last decade, mainly because of improved stability of spectrometers and the electron column when operated at high probe current; development of new large-area crystal monochromators and ultra-high count rate spectrometers; full integration of energy-dispersive / wavelength-dispersive X-ray spectrometry (EDS/WDS) signals; and the development of powerful software packages. For phases that are stable under a dense electron beam, the detection limit and precision can be decreased to the ppm level by using high acceleration voltage and beam current combined with long counting time. Data on 10 elements (Na, Al, P, Ca, Ti, Cr, Mn, Co, Ni, Zn) in olivine obtained on a JEOL JXA-8230 microprobe with tungsten filament show that the detection limit decreases proportionally to the square root of counting time and probe current. For all elements equal or heavier than phosphorus (Z = 15), the detection limit decreases with increasing accelerating voltage. The analytical precision for minor and trace elements analysed in olivine at 25 kV accelerating voltage and 900 nA beam current is 4 - 18 ppm (2 standard deviations of repeated measurements of the olivine reference sample) and is similar to the detection limit of corresponding elements. To analyse trace elements accurately requires careful estimation of background, and consideration of sample damage under the beam and secondary fluorescence from phase boundaries. The development and use of matrix reference samples with well-characterised trace elements of interest is important for monitoring and improving of the accuracy. An evaluation of the accuracy of trace element analyses in olivine has been made by comparing EPMA data for new reference samples with data obtained by different in-situ and bulk analytical methods in six different laboratories worldwide. For all elements, the measured concentrations in the olivine reference sample

Amperometric Sensor for Detection of Chloride Ions

Directory of Open Access Journals (Sweden)

Rene Kizek

2008-09-01

Full Text Available Chloride ion sensing is important in many fields such as clinical diagnosis, environmental monitoring and industrial applications. We have measured chloride ions at a carbon paste electrode (CPE and at a CPE modified with solid AgNO3, a solution of AgNO3 and/or solid silver particles. Detection limits (3 S/N for chloride ions were 100 μM, 100 μM and 10 μM for solid AgNO3, solution of AgNO3 and/or solid silver particles, respectively. The CPE modified with silver particles is the most sensitive to the presence chloride ions. After that we approached to the miniaturization of the whole electrochemical instrument. Measurements were carried out on miniaturized instrument consisting of a potentiostat with dimensions 35 × 166 × 125 mm, screen printed electrodes, a peristaltic pump and a PC with control software. Under the most suitable experimental conditions (Britton-Robinson buffer, pH 1.8 and working electrode potential 550 mV we estimated the limit of detection (3 S/N as 500 nM.

New technique for alpha particles detection

International Nuclear Information System (INIS)

Morsy, A.A.; Khattab, F.M.

1998-01-01

Man possesses no biological sensors of ionizing radiation as a consequence he must depend entirely on instrumentation for the detection and measurement of radiation. The recent discovery of the solid state nuclear track detection ( SSNTD ) techniques and its advantages over other dosimeters made them a useful tool for radiation dosimetry. This work is devoted to review and illustrate the application of SSNTD technique in some branches of science and technology specially the newly produced TASTRAK obtained from Track Analysis System Limited, Bristol, UK. The detector is successfully irradiated, chemically etched and calibrated for the aim of the Alpha radiation dosimetry

Technical testing of portable isotope identification instruments

International Nuclear Information System (INIS)

Smith, D.E.

2001-01-01

Full text: The United States Customs Service has, as a part of its mission, the protection of the borders of the United States from the import or export of illicit radioactive materials. Of paramount importance is the ability to interdict the smuggling of special nuclear material, nuclear weapons and other radioactive materials that could be used as a weapon of mass destruction against the population and infrastructure of the U.S. or another country. Radiation detection technology exists in the form of pocket size, hand-held and portal radiation detectors that have the ability to detect radiation with great sensitivity and low false alarm rates. U.S. Customs has chosen to implement pocket size detectors or radiation pagers as the personal tool of each inspector for the detection of radioactive material. In the search for illicit shipment of radioactive materials, innocent radiation detections may occur with some frequency due to common radioactive sources that may be encountered in day to day living. Examples include lantern mantles, some camera lenses, welding rods, certain dishware containing uranium glaze, and natural marble objects such as statues or architectural pieces. Perhaps the most common innocent detection encountered at the border and in public areas in general is due to the in vivo placement of radioactive sources for use in nuclear medicine therapy and diagnostics. Outpatients from such therapy can remain detectable for three weeks or more. Also, legal shipments of radioisotopes are common occurrences in cargo and express mail shipments. The customs inspector who detects radioactive material in the course of his duties must decide whether detection is innocent; is indicative of a nuclear device or special nuclear material; or whether the source could be injurious to him/her or the general public. It is at this point that a portable instrument capable of identifying gamma or neutron emitting isotopes is essential to the customs examination procedure

Quarry detection monitoring wells completion report WP-166

International Nuclear Information System (INIS)

1991-09-01

The purpose of this report is to document the activities undertaken during implementation of Work Package 166, Quarry Detection Monitoring Wells, for the Weldon Spring Site Remedial action project, Weldon Spring, Missouri. The subcontract specifications should be consulted for specific details regarding this work effort. Analytical parameters for soil samples collected for all but one borehole were analyzed for uranium, thorium, cyanide, nitroaromatics, and all Hazardous Substance List parameters including volatiles, semivolatiles, pesticides, polychlorinated biphenyls (PCBs) and metals. No soil samples were collected at other borehole as per specifications. With Z exceptions, uranium results for all boreholes sampled were at background levels. Nitroaromatics and cyanide were not detected in any of the samples collected. Volatile and semivolatile organics were not detected in the soil samples collected from the boreholes, with the exception of common lab contaminants such as methylene chloride, toluene, acetone, and pathalates. All metals results were either within their natural background ranges or below the detection limit of the instrument. PCB's were not detected within any of the boreholes. Pesticides detected (aldrin and methoxychlor) at one borehole near the surface may be attributed to previous spraying of pesticides on the highway right-of-way. In conclusion, the analytical results show that only uranium was detected in significant quantities; all other results were below the detection limit, very near the detection limit, or within natural background ranges. 1 fig

Teaching Students to Be Instrumental in Analysis: Peer-Led Team Learning in the Instrumental Laboratory

Science.gov (United States)

Williams, Jacob L.; Miller, Martin E.; Avitabile, Brianna C.; Burrow, Dillon L.; Schmittou, Allison N.; Mann, Meagan K.; Hiatt, Leslie A.

2017-01-01

Many instrumental analysis students develop limited skills as the course rushes through different instruments to ensure familiarity with as many methodologies as possible. This broad coverage comes at the expense of superficiality of learning and a lack of student confidence and engagement. To mitigate these issues, a peer-led team learning model…

Application of Statistical Methods to Activation Analytical Results near the Limit of Detection

DEFF Research Database (Denmark)

Heydorn, Kaj; Wanscher, B.

1978-01-01

Reporting actual numbers instead of upper limits for analytical results at or below the detection limit may produce reliable data when these numbers are subjected to appropriate statistical processing. Particularly in radiometric methods, such as activation analysis, where individual standard...... deviations of analytical results may be estimated, improved discrimination may be based on the Analysis of Precision. Actual experimental results from a study of the concentrations of arsenic in human skin demonstrate the power of this principle....

Innovative instrumentation

International Nuclear Information System (INIS)

Anon.

1983-01-01

At this year's particle physics conference at Brighton, a parallel session was given over to instrumentation and detector development. While this work is vital to the health of research and its continued progress, its share of prime international conference time is limited. Instrumentation can be innovative three times — first when a new idea is outlined, secondly when it is shown to be feasible, and finally when it becomes productive in a real experiment, amassing useful data rather than operational experience. Hyams' examples showed that it can take a long time for a new idea to filter through these successive stages, if it ever makes it at all

Innovative instrumentation

Energy Technology Data Exchange (ETDEWEB)

Anon.

1983-11-15

At this year's particle physics conference at Brighton, a parallel session was given over to instrumentation and detector development. While this work is vital to the health of research and its continued progress, its share of prime international conference time is limited. Instrumentation can be innovative three times — first when a new idea is outlined, secondly when it is shown to be feasible, and finally when it becomes productive in a real experiment, amassing useful data rather than operational experience. Hyams' examples showed that it can take a long time for a new idea to filter through these successive stages, if it ever makes it at all.

TXRF 'measurements' of concentration distribution below the detection limit

International Nuclear Information System (INIS)

Kubala-Kukus, A.; Banas, D.; Braziewicz, J.; Majewska, U.; Mrowczynski, S.; Pajek, M.

2000-01-01

We demonstrate that a shape of the concentration distribution of the element in a set of samples, as measured by the TXRF method, can be determined even for the concentrations below the detection limit (DL). This can be done, when the measurements reporting the concentration below DL level are included properly in the analysis of the results. The method developed for such correction is presented and discussed. It is demonstrated that this correction is particularly important when the studied concentrations are close to the DL level of the method, which is a common case for TXRF. In the paper a precision of the developed correction is discussed in details, by using the results of numerical simulations of experiments for different concentration distributions and number of performed measurements. It is demonstrated that the factor, which limits the accuracy of the correction, is the number of measurements, not the correction procedure itself. The applicability and importance of the developed correction is demonstrated for routine TXRF analysis of different types of samples of bio-medical interest. (author)

Investigation on feasibility and detection limits for determination of coating film thickness by neutron activation analysis

International Nuclear Information System (INIS)

Yao Maoying; Xu Jiayun; Zhang Dida; Yang Zunyong; Yao Zhenqiang; Wang Mingqiu; Gao Dangzhong

2010-01-01

A method for the determination of coating film thickness by neutron activation was proposed in this paper. After Au, Al and Cu et al.films were activated with a Am-Be neutron source, the characteristic γ-rays emitted by the activated nuclides in the films were counted with a HPGe γ spectrometer. The detection limits of film thickness by using a nuclear reactor neutron source were deduced on the basis of the γ-ray counts and the Monte-Carlo simulated detection efficiencies. The possible detection limits are typically 4-5 orders of magnitude better than those by fluorescent X-ray method, which is currently widely used to determine coating film thickness. (authors)

Discuss the technology for decrease the detection limit of NaI(Tl) gamma spectrometer

International Nuclear Information System (INIS)

Guo Xiaobin; Qu Guopu; Liu Zhiying; Wang Hongyan; Wang Lieming

2011-01-01

The radioelement species is complex and quantity is few after nuclear explosion, thus it is hard to tell the difference when using the Nal (TI) Gamma spectrometer detection due to several kinds of the peak of nuclide overlapped in the scattering region. So there is a high demand for spectrometer stability, energy resolution, solution spectrum and minimum detective activity. The paper analysed the influenced factors to Nal (TI) Gamma spectrometer and the measures of detection limit decrease by experiments and MCNP simulation, which proposed the methods to reduce background through shielding in order to improve minimum detective activity. The experiment shows that choosing reasonable shielding can reduce the background effectively and improve the spectrometer low level radioactive detect ability. (authors)

Tracking-by-detection of surgical instruments in minimally invasive surgery via the convolutional neural network deep learning-based method.

Science.gov (United States)

Zhao, Zijian; Voros, Sandrine; Weng, Ying; Chang, Faliang; Li, Ruijian

2017-12-01

Worldwide propagation of minimally invasive surgeries (MIS) is hindered by their drawback of indirect observation and manipulation, while monitoring of surgical instruments moving in the operated body required by surgeons is a challenging problem. Tracking of surgical instruments by vision-based methods is quite lucrative, due to its flexible implementation via software-based control with no need to modify instruments or surgical workflow. A MIS instrument is conventionally split into a shaft and end-effector portions, while a 2D/3D tracking-by-detection framework is proposed, which performs the shaft tracking followed by the end-effector one. The former portion is described by line features via the RANSAC scheme, while the latter is depicted by special image features based on deep learning through a well-trained convolutional neural network. The method verification in 2D and 3D formulation is performed through the experiments on ex-vivo video sequences, while qualitative validation on in-vivo video sequences is obtained. The proposed method provides robust and accurate tracking, which is confirmed by the experimental results: its 3D performance in ex-vivo video sequences exceeds those of the available state-of -the-art methods. Moreover, the experiments on in-vivo sequences demonstrate that the proposed method can tackle the difficult condition of tracking with unknown camera parameters. Further refinements of the method will refer to the occlusion and multi-instrumental MIS applications.

Nuclear instrumentation systems in prototype fast breeder reactor

International Nuclear Information System (INIS)

Vijayakumaran, P.M.; Nagaraj, C.P.; Paramasivan-Pillai, C.; Ramakrishnan, R.; Sivaramakrishna, M.

2004-01-01

The nuclear instrumentation systems of the Prototype Fast Breeder Reactor (PFBR) primarily comprise of global Neutron Flux Monitoring, Failed Fuel Detection and Location, Radiation Monitoring and Post-Accident Monitoring. High temperature fission chambers are provided at in-vessel locations for monitoring neutron flux. Failed fuel detection and location is by monitoring the cover gas for fission gases and primary sodium for delayed neutrons. Signals of the core monitoring detectors are used to initiate SCRAM (safety action) to protect the reactor from various postulated initiating events. Radiation levels in all potentially radioactive areas are monitored to act as an early warning system to keep the release of radioactivity to the environment and exposure to personnel well below the permissible limits. Fission Chambers and Gamma Ionisation Chambers are located in the reactor vault concrete for monitoring the neutron flux and gamma radiation levels during and after an accident. (authors)

Impact of instrument response variations on health physics measurements

International Nuclear Information System (INIS)

Armantrout, G.A.

1984-10-01

Uncertainties in estimating the potential health impact of a given radiation exposure include instrument measurement error in determining exposure and difficulty in relating this exposure to an effective dose value. Instrument error can be due to design or manufacturing deficiencies, limitations of the sensing element used, and calibration and maintenance of the instrument. This paper evaluates the errors which can be introduced by design deficiencies and limitations of the sensing element for a wide variety of commonly used survey instruments. The results indicate little difference among sensing element choice for general survey work, with variations among specific instrument designs being the major factor. Ion chamber instruments tend to be the best for all around use, while scintillator-based units should not be used where accurate measurements are required. The need to properly calibrate and maintain an instrument appears to be the most important factor in instrument accuracy. 8 references, 6 tables

Single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation in surgical treatment for single-segment lumbar spinal tuberculosis

OpenAIRE

Zeng, Hao; Wang, Xiyang; Zhang, Penghui; Peng, Wei; Zhang, Yupeng; Liu, Zheng

2015-01-01

Objective: The aim of this study is to determine the feasibility and efficacy of surgical management of single-segment lumbar spinal tuberculosis (TB) by using single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reconstruction, and posterior instrumentation.Methods: Seventeen cases of single-segment lumbar TB were treated with single-stage posterior transforaminal lumbar interbody fusion, debridement, limited decompression, 3-column reco...

Light emitting diode, photodiode-based fluorescence detection system for DNA analysis with microchip electrophoresis.

Science.gov (United States)

Hall, Gordon H; Glerum, D Moira; Backhouse, Christopher J

2016-02-01

Electrophoretic separation of fluorescently end-labeled DNA after a PCR serves as a gold standard in genetic diagnostics. Because of their size and cost, instruments for this type of analysis have had limited market uptake, particularly for point-of-care applications. This might be changed through a higher level of system integration and lower instrument costs that can be realized through the use of LEDs for excitation and photodiodes for detection--if they provide sufficient sensitivity. Here, we demonstrate an optimized microchip electrophoresis instrument using polymeric fluidic chips with fluorescence detection of end-labeled DNA with a LOD of 0.15 nM of Alexa Fluor 532. This represents orders of magnitude improvement over previously reported instruments of this type. We demonstrate the system with an electrophoretic separation of two PCR products and their respective primers. We believe that this is the first LED-induced fluorescence microchip electrophoresis system with photodiode-based detection that could be used for standard applications of PCR and electrophoresis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of a single-item screening question to detect limited health literacy in peritoneal dialysis patients.

Science.gov (United States)

Jain, Deepika; Sheth, Heena; Bender, Filitsa H; Weisbord, Steven D; Green, Jamie A

2014-01-01

Studies have shown that a single-item question might be useful in identifying patients with limited health literacy. However, the utility of the approach has not been studied in patients receiving maintenance peritoneal dialysis (PD). We assessed health literacy in a cohort of 31 PD patients by administering the Rapid Estimate of Adult Literacy in Medicine (REALM) and a single-item health literacy (SHL) screening question "How confident are you filling out medical forms by yourself?" (Extremely, Quite a bit, Somewhat, A little bit, or Not at all). To determine the accuracy of the single-item question for detecting limited health literacy, we performed sensitivity and specificity analyses of the SHL and plotted the area under the receiver operating characteristic (AUROC) curve using the REALM as a reference standard. Using a cut-off of "Somewhat" or less confident, the sensitivity of the SHL for detecting limited health literacy was 80%, and the specificity was 88%. The positive likelihood ratio was 6.9. The SHL had an AUROC of 0.79 (95% confidence interval: 0.52 to 1.00). Our results show that the SHL could be effective in detecting limited health literacy in PD patients.

Current studies of biological materials using instrumental and radiochemical neutron activation analysis

International Nuclear Information System (INIS)

Fardy, J.J.; McOrist, G.D.; Farrar, Y.J.

1985-01-01

Instrumental neutron activation analysis still remains the preferred option when analysing the trace element distribution in a wide rage of materials by neutron activation analysis. However, when lower limits of detection are required or major interferences reduce the effectiveness of this technique, radiochemical neutron activation analysis is applied. This paper examines the current use of both methods and the development of rapid radiochemical techniques for analysis of the biological materials, hair, cow's milk, human's milk, milk powder, blood and blood serum

Instrumental analysis by gamma spectrometry of low level caesium-137 in marine samples

International Nuclear Information System (INIS)

Figueira, R.C.L.; Silva, L.R.N.; Figueiredo, A.M.G.; Cunha, I.I.L.

1998-01-01

An instrumental method for the analysis of low levels of 137 Cs in marine samples consists in calibrating the detector, determining the counting efficiency of the detector, accumulative counts of background and sample and smoothing the 661.6 keV photopeak. The methodology was applied to reference samples containing low levels of 137 Cs, showing a good accuracy. It was further applied to sediment samples from the southern coast of Brazil. The levels obtained ranged between 1.0 and 1.8 Bq.kg -1 , and the lower limit of detection and minimum detectable concentration values were 10 mBq and 0.28 Bq.kg -1 , respectively. (author)

Proceedings of symposium on intelligent nuclear instrumentation-2001

International Nuclear Information System (INIS)

Kataria, S.K.; Vaidya, P.P.; Das, Debashis; Narurkar, P.V.

2001-02-01

Advances in the field of instrumentation are relevant to many areas of importance such as nuclear and accelerator based research, reactor monitoring and control, non-destructive testing and evaluation, laser programme and health and environment monitoring etc. The nuclear instrumentation is a specialized field with very specific expertise in detection, processing and its analysis. The symposium covers various fields of nuclear interest such as radiation detectors, application of ASICs and FPGA in instruments, field instruments, nuclear instrumentation for basic research, accelerator, reactor, health and environmental monitoring instrumentation, medical instrumentation, instrument net working inclusive of field buses, WEB based and wireless technologies, software tools, AI technique in instrumentation etc., in this specialized area. Papers relevant to INIS are indexed separately

Investigation of the Nitrogen Dioxide Pollution in Urban Areas using a New Portable ICAD Instrument

Science.gov (United States)

Horbanski, Martin; Pöhler, Denis; Adler, Tim; Lampel, Johannes; Kanatschnig, Florian; Oesterle, Tobias; Reh, Miriam; Platt, Ulrich

2016-04-01

Nitrogen oxides (NOx) and especially nitrogen dioxide (NO2), are still among of the most problematic pollutants in urban areas not only in developing, but also in industrialized countries. Despite the measures taken to reduce their emissions, NO2 concentrations in many urban areas exceed the WHO recommended limits of 40 μg/m3 for annual mean and 200 μg/m3 for 1 hour mean. Additionally it is known that the NO2 concentration in urban areas has a strong spatial and temporal variability, due to the large number of NOx emitting point sources (mainly traffic) found in densely populated areas. However, the layout of air monitoring networks in most urban areas, installed to continuously monitor the officially prescribed NO2 limits, does not reflect the high spatial variability because they only conduct measurements at a single or few selected sampling points, mainly on major roads, which are often not representative for the whole urban area. At present these uncertainties about the spatial NO2 distribution constitute severe limitations for the assessment of health risks, for the quality of chemical model calculations, and for developing effective measures to reduce NOx emissions. We developed a new light-weight and portable ICAD (Iterative Cavity Enhanced DOAS) instrument which detects NO2 at a detection limit as low as 0.2 μg/m3 with a high time resolution of seconds. The instrument is based on the Cavity Enhanced (CE-) DOAS technique, which directly identifies and quantifies NO2 by its differential optical absorption. Therefore, it does not suffer from interferences by other trace gas species like O3 or NOy. This is a great advantage over other NO2 instruments (e.g. solid state detectors or chemiluminescence instruments). We present the result of ICAD NO2 measurements, which we recently performed in more than 10 German cities. The ICAD instrument was mounted on mobile platforms like cars and bicycles, measuring the NO2 concentrations along carefully selected tracks

Ultrasonic imaging with a fixed instrument configuration

Energy Technology Data Exchange (ETDEWEB)

Witten, A.; Tuggle, J.; Waag, R.C.

1988-07-04

Diffraction tomography is a technique based on an inversion of the wave equation which has been proposed for high-resolution ultrasonic imaging. While this approach has been considered for diagnostic medical applications, it has, until recently, been limited by practical limitations on the speed of data acquisition associated with instrument motions. This letter presents the results of an experimental study directed towards demonstrating tomography utilizing a fixed instrument configuration.

Alpha detection on moving surfaces

International Nuclear Information System (INIS)

MacArthur, D.; Orr, C.; Luff, C.

1998-01-01

Both environmental restoration (ER) and decontamination and decommissioning (D and D) require characterization of large surface areas (walls, floors, in situ soil, soil and rubble on a conveyor belt, etc.) for radioactive contamination. Many facilities which have processed alpha active material such as plutonium or uranium require effective and efficient characterization for alpha contamination. Traditional methods for alpha surface characterization are limited by the short range and poor penetration of alpha particles. These probes are only sensitive to contamination located directly under the probe. Furthermore, the probe must be held close to the surface to be monitored in order to avoid excessive losses in the ambient air. The combination of proximity and thin detector windows can easily cause instrument damage unless extreme care is taken. The long-range alpha detection (LRAD) system addresses these problems by detecting the ions generated by alpha particles interacting with ambient air rather than the alpha particle directly. Thus, detectors based on LRAD overcome the limitations due to alpha particle range (the ions can travel many meters as opposed to the several-centimeter alpha particle range) and penetrating ability (an LRAD-based detector has no window). Unfortunately, all LRAD-based detectors described previously are static devices, i.e., these detectors cannot be used over surfaces which are continuously moving. In this paper, the authors report on the first tests of two techniques (the electrostatic ion seal and the gridded electrostatic LRAD detector) which extend the capabilities of LRAD surface monitors to use over moving surfaces. This dynamic surface monitoring system was developed jointly by Los Alamos National Laboratory and at BNFL Instruments. All testing was performed at the BNFL Instruments facility in the UK

Nucleonic instruments from VUPJT Tesla

International Nuclear Information System (INIS)

Smola, J.

1986-01-01

The instruments currently produced by Tesla Premysleni are listed and briefly characterized. They include a low level alpha-beta counter, an automatic low level alpha-beta counter, detection units for environmental sample counting, instruments for measuring specific activity of liquids and radon concentration in water, a radioactive aerosol meter, dose ratemeters, portable alpha-beta indicators for surface contamintion monitoring, neutron monitors, single-, two- and three-channel spectrometric units. (M.D.)

Health Status Measurement Instruments in Chronic Obstructive Pulmonary Disease

Directory of Open Access Journals (Sweden)

Yves Lacasse

1997-01-01

Full Text Available Chronic obstructive pulmonary disease (COPD is associated with primary respiratory impairment, disability and handicap, as well as with secondary impairments not necessarily confined to the respiratory system. Because the primary goals of managing patients with COPD include relief of dyspnea and the improvement of health-related quality of life (HRQL, a direct measurement of HRQL is important. Fourteen disease-specific and nine generic questionnaires (four health profiles and five utility measures most commonly used to measure health status in patients with COPD were reviewed. The measures were classified according to their domain of interest, and their measurement properties - specifications, validity, reliability, responsiveness and interpretability - were described. This review suggests several findings. Currently used health status instruments usually refer to the patients’ perception of performance in three major domains of HRQL - somatic sensation, physical and occupational function, and psychological state. The choice of a questionnaire must be related to its purpose, with a clear distinction being made between its evaluative and discriminative function. In their evaluative function, only a few instruments fulfilled the criteria of responsiveness, and the interpretability of most questionnaires is limited. Generic questionnaires should not be used alone in clinical trials as evaluative instruments because of their inability to detect change over time. Further validation and improved interpretability of existing instruments would be of greater benefit to clinicians and scientists than the development of new questionnaires.

Power-limited low-thrust trajectory optimization with operation point detection

Science.gov (United States)

Chi, Zhemin; Li, Haiyang; Jiang, Fanghua; Li, Junfeng

2018-06-01

The power-limited solar electric propulsion system is considered more practical in mission design. An accurate mathematical model of the propulsion system, based on experimental data of the power generation system, is used in this paper. An indirect method is used to deal with the time-optimal and fuel-optimal control problems, in which the solar electric propulsion system is described using a finite number of operation points, which are characterized by different pairs of thruster input power. In order to guarantee the integral accuracy for the discrete power-limited problem, a power operation detection technique is embedded in the fourth-order Runge-Kutta algorithm with fixed step. Moreover, the logarithmic homotopy method and normalization technique are employed to overcome the difficulties caused by using indirect methods. Three numerical simulations with actual propulsion systems are given to substantiate the feasibility and efficiency of the proposed method.

STATISTICAL METHODS FOR ENVIRONMENTAL APPLICATIONS USING DATA SETS WITH BELOW DETECTION LIMIT OBSERVATIONS AS INCORPORTED IN PROUCL 4.0

Science.gov (United States)

Nondetect (ND) or below detection limit (BDL) results cannot be measured accurately, and, therefore, are reported as less than certain detection limit (DL) values. However, since the presence of some contaminants (e.g., dioxin) in environmental media may pose a threat to human he...

CARIES DETECTION WITH LASER FLUORESCENCE DEVICES. LIMITATIONS OF THEIR USE

Directory of Open Access Journals (Sweden)

Andreas Spaveras

2017-03-01

Data synthesis: DD and DDPen are useful devices for caries detection on the occlusal tooth surfaces. Their main advantages are the very high reproducibility of measurements (>0.90, the ease of handling and the quantification and monitoring capacity. Their main limitations are the relatively low specificity for enamel lesions, the necessity of unstained surfaces and absence of plaque and pastes during measurements and the absence of a universal, clinically functional calibration value (COV. Conclusion: Further studies are required for more reliable data analysis and clinical interpretation of the relevant results.

14 CFR 121.303 - Airplane instruments and equipment.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplane instruments and equipment. 121.303... Airplane instruments and equipment. (a) Unless otherwise specified, the instrument and equipment... airspeed limitation and item of related information in the Airplane Flight Manual and pertinent placards...

Real time in situ detection of organic nitrates in atmospheric aerosols.

Science.gov (United States)

Rollins, Andrew W; Smith, Jared D; Wilson, Kevin R; Cohen, Ronald C

2010-07-15

A novel instrument is described that quantifies total particle-phase organic nitrates in real time with a detection limit of 0.11 microg m(-3) min(-1), 45 ppt min(-1) (-ONO(2)). Aerosol nitrates are separated from gas-phase nitrates with a short residence time activated carbon denuder. Detection of organic molecules containing -ONO(2) subunits is accomplished using thermal dissociation coupled to laser induced fluorescence detection of NO(2). This instrument is capable of high time resolution (seconds) measurements of particle-phase organic nitrates, without interference from inorganic nitrate. Here we use it to quantify organic nitrates in secondary organic aerosol generated from high-NO(x) photooxidation of limonene, alpha-pinene, Delta-3-carene, and tridecane. In these experiments the organic nitrate moiety is observed to be 6-15% of the total SOA mass.

Overview of intercalibration of satellite instruments

Science.gov (United States)

Chander, G.; Hewison, T.J.; Fox, N.; Wu, X.; Xiong, X.; Blackwell, W.J.

2013-01-01

Inter-calibration of satellite instruments is critical for detection and quantification of changes in the Earth’s environment, weather forecasting, understanding climate processes, and monitoring climate and land cover change. These applications use data from many satellites; for the data to be inter-operable, the instruments must be cross-calibrated. To meet the stringent needs of such applications requires that instruments provide reliable, accurate, and consistent measurements over time. Robust techniques are required to ensure that observations from different instruments can be normalized to a common scale that the community agrees on. The long-term reliability of this process needs to be sustained in accordance with established reference standards and best practices. Furthermore, establishing physical meaning to the information through robust Système International d'unités (SI) traceable Calibration and Validation (Cal/Val) is essential to fully understand the parameters under observation. The processes of calibration, correction, stability monitoring, and quality assurance need to be underpinned and evidenced by comparison with “peer instruments” and, ideally, highly calibrated in-orbit reference instruments. Inter-calibration between instruments is a central pillar of the Cal/Val strategies of many national and international satellite remote sensing organizations. Inter-calibration techniques as outlined in this paper not only provide a practical means of identifying and correcting relative biases in radiometric calibration between instruments but also enable potential data gaps between measurement records in a critical time series to be bridged. Use of a robust set of internationally agreed upon and coordinated inter-calibration techniques will lead to significant improvement in the consistency between satellite instruments and facilitate accurate monitoring of the Earth’s climate at uncertainty levels needed to detect and attribute the mechanisms

Instrumentation measurement and testing complex for detection and identification of radioactive materials using the emitted radiation

International Nuclear Information System (INIS)

Samossadny, V.T.; Dmitrenko, V.V.; Kadlin, V.V.; Kolesnikov, S.V.; Ulin, S.E.; Grachev, V.M.; Vlasik, K.F.; Dedenko, G.L.; Novikov, D.V.; Uteshev, Z.M.

2006-01-01

Simultaneous measurement of neutron and gamma radiation is a very usefull method for effective nuclear materials identification and control. The gamma-ray-neutron complex described in the paper is based on two multi-layer 3 He neutrons detectors and two High Pressure Xenon gamma-ray spectrometers assembled in one unit. All these detectors were callibrated on neutron and gamma-ray sources. The main characteristics of the instrumentation , its testing results and gamma-ray and neutron radiation parameters, which have been measured are represented in the paper. The gamma-neutron sources and fissile materials reliable detection and identification capability was demonstrated

A compact PTR-ToF-MS instrument for airborne measurements of volatile organic compounds at high spatiotemporal resolution

Directory of Open Access Journals (Sweden)

M. Müller

2014-11-01

Full Text Available Herein, we report on the development of a compact proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS for airborne measurements of volatile organic compounds (VOCs. The new instrument resolves isobaric ions with a mass resolving power (m/Δm of ~1000, provides accurate m/z measurements (Δm < 3 mDa, records full mass spectra at 1 Hz and thus overcomes some of the major analytical deficiencies of quadrupole-MS-based airborne instruments. 1 Hz detection limits for biogenic VOCs (isoprene, α total monoterpenes, aromatic VOCs (benzene, toluene, xylenes and ketones (acetone, methyl ethyl ketone range from 0.05 to 0.12 ppbV, making the instrument well-suited for fast measurements of abundant VOCs in the continental boundary layer. The instrument detects and quantifies VOCs in locally confined plumes (< 1 km, which improves our capability of characterizing emission sources and atmospheric processing within plumes. A deployment during the NASA 2013 DISCOVER-AQ mission generated high vertical- and horizontal-resolution in situ data of VOCs and ammonia for the validation of satellite retrievals and chemistry transport models.

Proposal for a methodology for the determination of the Detection Limit: Case of bulks detector for the Chlorothalonil

International Nuclear Information System (INIS)

Gonzalez G, J.; Parra M, C.M.; Romero R, R.M.

1998-01-01

As it usually found in the literature, the Lower Detection Limit for an analytical method is obtained by means of a simple statistical exercise whose value is seldom attained in practice. For this reason a method was designed for achieving a Practical Lower Detection Limit for the lowest concentration of the compound that could be detected, S= 2 R, with a probability of at least, 0.90. A methodological design was formulated to get a Practical Lower Detection Limit that is not timed consuming for the analyst. It is presented using an example and, additionally its benefits are discussed versus the unattainable values that are obtained by the traditional use of the standard deviation of a series of measurements of the compound at concentrations near zero, which is then multiplied by the t student for a one tailed test for n-1 degrees of freedom

Portable radiation instrumentation traceability of standards and measurements

International Nuclear Information System (INIS)

Wiserman, A.; Walke, M.

1995-01-01

Portable radiation measuring instruments are used to estimate and control doses for workers. Calibration of these instruments must be sufficiently accurate to ensure that administrative and legal dose limits are not likely to be exceeded due to measurement uncertainties. An instrument calibration and management program is established which permits measurements made with an instrument to be traced to a national standard. This paper describes the establishment and maintenance of calibration standards for gamma survey instruments and an instrument management program which achieves traceability of measurement for uniquely identified field instruments. (author)

Surveillance of instruments by noise analysis

International Nuclear Information System (INIS)

Thie, J.A.

1981-01-01

Random fluctuations of neutron flux, temperature, and pressure in a reactor provide multifrequency excitation of the corresponding instrumentation chains. Mathematical descriptors suitable for characterizing the output, or noise, of the instrumentation are reviewed with a view toward using such noise in detecting instrument faults. Demonstrations of the feasibility of this approach in a number of reactors provide illustrative examples. Comparisons with traditional surveillance testing are made, and a number of advantages and some disadvantages of using noise analysis as a supplementary technique are pointed out

Improved GLR method to instrument failure detection

International Nuclear Information System (INIS)

Jeong, Hak Yeoung; Chang, Soon Heung

1985-01-01

The generalized likehood radio(GLR) method performs statistical tests on the innovations sequence of a Kalman-Buchy filter state estimator for system failure detection and its identification. However, the major drawback of the convensional GLR is to hypothesize particular failure type in each case. In this paper, a method to solve this drawback is proposed. The improved GLR method is applied to a PWR pressurizer and gives successful results in detection and identification of any failure. Furthmore, some benefit on the processing time per each cycle of failure detection and its identification can be accompanied. (Author)

Feasibility of Detecting Bioorganic Compounds in Enceladus Plumes with the Enceladus Organic Analyzer

Science.gov (United States)

Razu, Md Enayet; Kim, Jungkyu; Stockton, Amanda M.; Turin, Paul; Butterworth, Anna

2017-01-01

Abstract Enceladus presents an excellent opportunity to detect organic molecules that are relevant for habitability as well as bioorganic molecules that provide evidence for extraterrestrial life because Enceladus' plume is composed of material from the subsurface ocean that has a high habitability potential and significant organic content. A primary challenge is to send instruments to Enceladus that can efficiently sample organic molecules in the plume and analyze for the most relevant molecules with the necessary detection limits. To this end, we present the scientific feasibility and engineering design of the Enceladus Organic Analyzer (EOA) that uses a microfluidic capillary electrophoresis system to provide sensitive detection of a wide range of relevant organic molecules, including amines, amino acids, and carboxylic acids, with ppm plume-detection limits (100 pM limits of detection). Importantly, the design of a capture plate that effectively gathers plume ice particles at encounter velocities from 200 m/s to 5 km/s is described, and the ice particle impact is modeled to demonstrate that material will be efficiently captured without organic decomposition. While the EOA can also operate on a landed mission, the relative technical ease of a fly-by mission to Enceladus, the possibility to nondestructively capture pristine samples from deep within the Enceladus ocean, plus the high sensitivity of the EOA instrument for molecules of bioorganic relevance for life detection argue for the inclusion of EOA on Enceladus missions. Key Words: Lab-on-a-chip—Organic biomarkers—Life detection—Planetary exploration. Astrobiology 17, 902–912. PMID:28915087

Detection limits should be a thing of the past in gamma-ray spectrometry in general as well as in neutron activation analysis

NARCIS (Netherlands)

Blaauw, Menno

2016-01-01

In gamma-ray spectrometry with high-resolution detectors, full-energy peaks are often to be detected by a peak-search algorithm, with a threshold for detection. Detection limits can be derived from this. Detection limits are often computed along with measured activities or concentrations. When an

Optimising Mycobacterium tuberculosis detection in resource limited settings.

Science.gov (United States)

Alfred, Nwofor; Lovette, Lawson; Aliyu, Gambo; Olusegun, Obasanya; Meshak, Panwal; Jilang, Tunkat; Iwakun, Mosunmola; Nnamdi, Emenyonu; Olubunmi, Onuoha; Dakum, Patrick; Abimiku, Alash'le

2014-03-03

The light-emitting diode (LED) fluorescence microscopy has made acid-fast bacilli (AFB) detection faster and efficient although its optimal performance in resource-limited settings is still being studied. We assessed the optimal performances of light and fluorescence microscopy in routine conditions of a resource-limited setting and evaluated the digestion time for sputum samples for maximum yield of positive cultures. Cross-sectional study. Facility-based involving samples of routine patients receiving tuberculosis treatment and care from the main tuberculosis case referral centre in northern Nigeria. The study included 450 sputum samples from 150 new patients with clinical diagnosis of pulmonary tuberculosis. The 450 samples were pooled into 150 specimens, examined independently with mercury vapour lamp (FM), LED CysCope (CY) and Primo Star iLED (PiLED) fluorescence microscopies, and with the Ziehl-Neelsen (ZN) microscopy to assess the performance of each technique compared with liquid culture. The cultured specimens were decontaminated with BD Mycoprep (4% NaOH-1% NLAC and 2.9% sodium citrate) for 10, 15 and 20 min before incubation in Mycobacterium growth incubator tube (MGIT) system and growth examined for acid-fast bacilli (AFB). Of the 150 specimens examined by direct microscopy: 44 (29%), 60 (40%), 49 (33%) and 64 (43%) were AFB positive by ZN, FM, CY and iLED microscopy, respectively. Digestion of sputum samples for 10, 15 and 20 min yielded mycobacterial growth in 72 (48%), 81 (54%) and 68 (45%) of the digested samples, respectively, after incubation in the MGIT system. In routine laboratory conditions of a resource-limited setting, our study has demonstrated the superiority of fluorescence microscopy over the conventional ZN technique. Digestion of sputum samples for 15 min yielded more positive cultures.

Estimation of the limit of detection with a bootstrap-derived standard error by a partly non-parametric approach. Application to HPLC drug assays

DEFF Research Database (Denmark)

Linnet, Kristian

2005-01-01

Bootstrap, HPLC, limit of blank, limit of detection, non-parametric statistics, type I and II errors......Bootstrap, HPLC, limit of blank, limit of detection, non-parametric statistics, type I and II errors...

Specialized instrument for radiation assistance teams

International Nuclear Information System (INIS)

Applegate, J.A.

1985-08-01

A specialized multiradiation instrument for radiation assistance teams (RAT's) has been designed; a working prototype has been constructed and field tested. The instrument detects alpha, beta, and gamma radiation simultaneously with simple red, yellow, and green meter indications and audio outputs. It is basically intended for DOE radiation assistance teams but would have application to any government, military, or industrial radiation accident team

The 2007 ESO Instrument Calibration Workshop

CERN Document Server

Kaufer, Andreas; ESO Workshop

2008-01-01

The 2007 ESO Instrument Calibration workshop brought together more than 120 participants with the objective to a) foster the sharing of information, experience and techniques between observers, instrument developers and instrument operation teams, b) review the actual precision and limitations of the applied instrument calibration plans, and c) collect the current and future requirements by the ESO users. These present proceedings include the majority of the workshop’s contributions and document the status quo of instrument calibration at ESO in large detail. Topics covered are: Optical Spectro-Imagers, Optical Multi-Object Spectrographs, NIR and MIR Spectro-Imagers, High-Resolution Spectrographs, Integral Field Spectrographs, Adaptive Optics Instruments, Polarimetric Instruments, Wide Field Imagers, Interferometric Instruments as well as other crucial aspects such as data flow, quality control, data reduction software and atmospheric effects. It was stated in the workshop that "calibration is a life-long l...

Detection limits for real-time source water monitoring using indigenous freshwater microalgae

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Jr, Miguel [ORNL; Greenbaum, Elias [ORNL

2009-01-01

This research identified toxin detection limits using the variable fluorescence of naturally occurring microalgae in source drinking water for five chemical toxins with different molecular structures and modes of toxicity. The five chemicals investigated were atrazine, Diuron, paraquat, methyl parathion, and potassium cyanide. Absolute threshold sensitivities of the algae for detection of the toxins in unmodified source drinking water were measured. Differential kinetics between the rate of action of the toxins and natural changes in algal physiology, such as diurnal photoinhibition, are significant enough that effects of the toxin can be detected and distinguished from the natural variance. This is true even for physiologically impaired algae where diminished photosynthetic capacity may arise from uncontrollable external factors such as nutrient starvation. Photoinhibition induced by high levels of solar radiation is a predictable and reversible phenomenon that can be dealt with using a period of dark adaption of 30 minutes or more.

Detection of organic compound signatures in infra-red, limb emission spectra observed by the MIPAS-B2 balloon instrument

Directory of Open Access Journals (Sweden)

J. J. Remedios

2007-01-01

Full Text Available Organic compounds play a central role in troposphere chemistry and increasingly are a viable target for remote sensing observations. In this paper, infra-red spectral features of three organic compounds are investigated in thermal emission spectra recorded on a flight on 8 May 1998 near Aire sur l'Adour by a balloon-borne instrument, MIPAS-B2, operating at high spectral resolution. It is demonstrated, for the first time, that PAN and acetone can be detected in infra-red remote sensing spectra of the upper troposphere; detection results are presented at tangent altitudes of 10.4 km and 7.5 km (not acetone. In addition, the results provide the first observation of spectral features of formic acid in thermal emission, as opposed to solar occultation, and confirm that concentrations of this gas are measurable in the mid-latitude upper troposphere, given accurate spectroscopic data. For PAN, two bands are observed centred at 794 cm−1 and 1163 cm−1. For acetone and formic acid, one band has been detected for each so far with band centres at 1218 cm−1 and 1105 cm−1 respectively. Mixing ratios inferred at 10.4 km tangent altitude are 180 pptv and 530 pptv for PAN and acetone respectively, and 200 pptv for formic acid with HITRAN 2000 spectroscopy. Accuracies are on the order of 15 to 40%. The detection technique applied here is verified by examining weak but known signatures of CFC-12 and HCFC-22 in the same spectral regions as those of the organic compounds, with results confirming the quality of both the instrument and the radiative transfer model. The results suggest the possibility of global sensing of the organic compounds studied here which would be a major step forward in verifying and interpreting global tropospheric model calculations.

Limits of 2D-TCA in detecting BOLD responses to epileptic activity.

Science.gov (United States)

Khatamian, Yasha Borna; Fahoum, Firas; Gotman, Jean

2011-05-01

Two-dimensional temporal clustering analysis (2D-TCA) is a relatively new functional MRI (fMRI) based technique that breaks blood oxygen level dependent activity into separate components based on timing and has shown potential for localizing epileptic activity independently of electroencephalography (EEG). 2D-TCA has only been applied to detect epileptic activity in a few studies and its limits in detecting activity of various forms (i.e. activation size, amplitude, and frequency) have not been investigated. This study evaluated 2D-TCA's ability to detect various forms of both simulated epileptic activity and EEG-fMRI activity detected in patients. When applied to simulated data, 2D-TCA consistently detected activity in 6min runs containing 5 spikes/run, 10 spikes/run, and one 5s long event with hemodynamic response function amplitudes of at least 1.5%, 1.25%, and 1% above baseline respectively. When applied to patient data, while detection of interictal spikes was inconsistent, 2D-TCA consistently produced results similar to those obtained by EEG-fMRI when at least 2 prolonged interictal events (a few seconds each) occurred during the run. However, even for such cases it was determined that 2D-TCA can only be used to validate localization by other means or to create hypotheses as to where activity may occur, as it also detects changes not caused by epileptic activity. Copyright © 2011 Elsevier B.V. All rights reserved.

APPLICATION OF THE SPECTROMETRIC METHOD FOR CALCULATING THE DOSE RATE FOR CREATING CALIBRATION HIGHLY SENSITIVE INSTRUMENTS BASED ON SCINTILLATION DETECTION UNITS

Directory of Open Access Journals (Sweden)

R. V. Lukashevich

2017-01-01

Full Text Available Devices based on scintillation detector are highly sensitive to photon radiation and are widely used to measure the environment dose rate. Modernization of the measuring path to minimize the error in measuring the response of the detector to gamma radiation has already reached its technological ceiling and does not give the proper effect. More promising for this purpose are new methods of processing the obtained spectrometric information. The purpose of this work is the development of highly sensitive instruments based on scintillation detection units using a spectrometric method for calculating dose rate.In this paper we consider the spectrometric method of dosimetry of gamma radiation based on the transformation of the measured instrumental spectrum. Using predetermined or measured functions of the detector response to the action of gamma radiation of a given energy and flux density, a certain function of the energy G(E is determined. Using this function as the core of the integral transformation from the field to dose characteristic, it is possible to obtain the dose value directly from the current instrumentation spectrum. Applying the function G(E to the energy distribution of the fluence of photon radiation in the environment, the total dose rate can be determined without information on the distribution of radioisotopes in the environment.To determine G(E by Monte-Carlo method instrumental response function of the scintillator detector to monoenergetic photon radiation sources as well as other characteristics are calculated. Then the whole full-scale energy range is divided into energy ranges for which the function G(E is calculated using a linear interpolation.Spectrometric method for dose calculation using the function G(E, which allows the use of scintillation detection units for a wide range of dosimetry applications is considered in the article. As well as describes the method of calculating this function by using Monte-Carlo methods

Liquid metal-to-gas leak-detection instruments

International Nuclear Information System (INIS)

Matlin, E.; Witherspoon, J.E.; Johnson, J.L.

1982-01-01

It is desirable for liquid-metal-cooled reactors that small liquid metal-to-gas leaks be reliably detected. Testing has been performed on a number of detection systems to evaluate their sensitivity, response time, and performance characteristics. This testing has been scheduled in three phases. The first phase was aimed at screening out the least suitable detectors and optimizing the performance of the most promising. In the second phase, candidates were tested in a 1500 ft 3 walk-in type enclosure in which leaks were simulated on 24-in. and 3-in. piping. In the third phase of testing, selected type detectors were tested in the 1500-ft 3 enclosure with Clinch River Breeder Reactor Plant (CRBRP) pipe insulation configurations and detector tubing configuration with cell gas recirculation simulated. Endurance testing of detection equipment was also performed as part of this effort. Test results have been shown that aerosol-type detectors will reliably detect leaks as small as a few grams per hour when sampling pipe insulation annuli

Instrumentation for Detecting Hazardous Materials.

Science.gov (United States)

1980-06-01

equipment a detector for monitoring radioactivity . A portable device for detecting the presence of hazardous mate- rials should also be included in the...Acrylonitrile 2 Natural Gas/LNG 2 211 ----- Material Name (Cont’d.) Number of Times Listed Radioactive Materials 2 Fertilizers 1 Cellulose Nitrate 1 Acrolein...Birnbaum, and Curtis Fincher, L "Fluorescence Determination of the Atmospheric Polutant NO2 in Impact of Lasers in Spectroscopy, Vol. 49 of Proceed

Detection Limits for Spectro-fluorometry: A Case Study in the Region of Finstersee, Canton Zug, Northern Switzerland

Science.gov (United States)

Otz, M. H.; Otz, H. K.; Keller, P.

2002-05-01

Synthetic fluorescent dyes, applied below the visual detection limit (< 0.1 mg/L), have been used as tracers of ground water flow paths since the beginning of the 1950s. Since 1965, we have used spectro-fluorometers with photomultipliers to measure low concentrations of fluorescent dyes in ground water in Switzerland. In collaboration with the Engineering Geology Department of the ETH, we have separated uranine at 0.1 ng/L and Na-naphtionate at 1 ng/L from background fluorescence of spring water in the Finstersee region. These values are 10-100 times lower than postulated detection limits in the literature. The use of low dye concentrations prevents a study region from being contaminated by increased background levels due to remnant dye within the aquifer, thereby leaving the region available for future dye tracing studies. Lower detection limits also can solve particular hydraulic problems where conventional methods fail and enhance the possibility for using artificial dyes in environmentally sensitive aquifer settings.

Instrument employing a charge flow transistor

International Nuclear Information System (INIS)

1981-01-01

The invention concerns instruments employing charge-flow transistors that operate to sense a property in the surrounding environment. It is based on a particular sensor principle, thin-film conduction. The instruments described include a charge-flow transistor with semiconductor substrate, a source region, a drain region, a gate insulator, and a gapped electrode structure with a thin-film sensor material in the gap. The sensor material has an electrical conductance that is sensitive to a property of the ambient environment and has a surface conductance that differs substantially from its bulk conductance. The main object is to provide a low-cost instrument for early-warning fire-detection devices: in this case the property detected would be the products of combustion. Other properties that can be sensed include gases or vapors, free radicals, vapor electromagnetic radiation, subatomic particles, atomic or molecular beams, changes in ambient pressure or temperature, the chemical composition and the electrochemical potential of a solution. (U.K.)

Instrument employing a charge flow transistor

Energy Technology Data Exchange (ETDEWEB)

1981-03-11

The invention concerns instruments employing charge-flow transistors that operate to sense a property in the surrounding environment. It is based on a particular sensor principle, thin-film conduction. The instruments described include a charge-flow transistor with semiconductor substrate, a source region, a drain region, a gate insulator, and a gapped electrode structure with a thin-film sensor material in the gap. The sensor material has an electrical conductance that is sensitive to a property of the ambient environment and has a surface conductance that differs substantially from its bulk conductance. The main object is to provide a low-cost instrument for early-warning fire-detection devices: in this case the property detected would be the products of combustion. Other properties that can be sensed include gases or vapors, free radicals, vapor electromagnetic radiation, subatomic particles, atomic or molecular beams, changes in ambient pressure or temperature, the chemical composition and the electrochemical potential of a solution.

Matrix effect on the detection limit and accuracy in total reflection X-ray fluorescence analysis of trace elements in environmental and biological samples

International Nuclear Information System (INIS)

Karjou, J.

2007-01-01

The effect of matrix contents on the detection limit of total reflection X-ray fluorescence analysis was experimentally investigated using a set of multielement standard solutions (500 ng/mL of each element) in variable concentrations of NH 4 NO 3 . It was found that high matrix concentration, i.e. 0.1-10% NH 4 NO 3 , had a strong effect on the detection limits for all investigated elements, whereas no effect was observed at lower matrix concentration, i.e. 0-0.1% NH 4 NO 3 . The effect of soil and blood sample masses on the detection limit was also studied. The results showed decreasing the detection limit (in concentration unit, μg/g) with increasing the sample mass. However, the detection limit increased (in mass unit, ng) with increasing sample mass. The optimal blood sample mass of ca. 200 μg was sufficient to improve the detection limit of Se determination by total reflection X-ray fluorescence. The capability of total reflection X-ray fluorescence to analyze different kinds of samples was discussed with respect to the accuracy and detection limits based on certified and reference materials. Direct analysis of unknown water samples from several sources was also presented in this work

Detection limits of Legionella pneumophila in environmental samples after co-culture with Acanthamoeba polyphaga

Science.gov (United States)

2013-01-01

Background The efficiency of recovery and the detection limit of Legionella after co-culture with Acanthamoeba polyphaga are not known and so far no investigations have been carried out to determine the efficiency of the recovery of Legionella spp. by co-culture and compare it with that of conventional culturing methods. This study aimed to assess the detection limits of co-culture compared to culture for Legionella pneumophila in compost and air samples. Compost and air samples were spiked with known concentrations of L. pneumophila. Direct culturing and co-culture with amoebae were used in parallel to isolate L. pneumophila and recovery standard curves for both methods were produced for each sample. Results The co-culture proved to be more sensitive than the reference method, detecting 102-103 L. pneumophila cells in 1 g of spiked compost or 1 m3 of spiked air, as compared to 105-106 cells in 1 g of spiked compost and 1 m3 of spiked air. Conclusions Co-culture with amoebae is a useful, sensitive and reliable technique to enrich L. pneumophila in environmental samples that contain only low amounts of bacterial cells. PMID:23442526

The coupling of capillary electrophoresis-inductively coupled plasma mass spectrometer as a speciation instrument for actinides at trace level; Le couplage electrophorese capillaire-spectrometre de masse a source plasma en tant qu'instrument de speciation des actinides a l'etat de traces

Energy Technology Data Exchange (ETDEWEB)

Delorme, A

2004-07-01

An interface between the separation technique (capillary electrophoresis) and the analytical technique (Inductively Coupled Plasma - Mass Spectrometer) was developed. In that sense, bibliographic and parametric studies allowed to define necessary conditions for the good working of both techniques. The results obtained led to the realisation of an interface capillary electrophoresis / ICP-MS (CE / ICP-MS). This one was experimentally validated on classical separations (alkalis / earth-alkalis and lanthanides) and the detection limit of the analytical system was determined equal to 4 x 10{sup -11} mol.L{sup -1} for plutonium. This result exhibits a gain in detection limit of a factor higher than 10{sup 4} compared to the capillary electrophoresis in standard detection (UV). The studies were made in order to check the capacity of the CE / ICP-MS coupling as a speciation instrument for actinides at trace level and to define the associated analytical procedures. The coupling turned out to be a suited instrument for the determination of absolute electrophoretic mobilities at infinite dilution (physico-chemical property which allows to predict the migration time of an ion under an electrical field in a given electrolyte), for the determination of thermodynamic constants and for the separation of different actinide oxidation states in solution. (author)

The Impact of Including Below Detection Limit Samples in Post Decommissioning Soil Sample Analyses

Energy Technology Data Exchange (ETDEWEB)

Kim, Jung Hwan; Yim, Man-Sung [KAIST, Daejeon (Korea, Republic of)

2016-10-15

To meet the required standards the site owner has to show that the soil at the facility has been sufficiently cleaned up. To do this one must know the contamination of the soil at the site prior to clean up. This involves sampling that soil to identify the degree of contamination. However there is a technical difficulty in determining how much decontamination should be done. The problem arises when measured samples are below the detection limit. Regulatory guidelines for site reuse after decommissioning are commonly challenged because the majority of the activity in the soil at or below the limit of detection. Using additional statistical analyses of contaminated soil after decommissioning is expected to have the following advantages: a better and more reliable probabilistic exposure assessment, better economics (lower project costs) and improved communication with the public. This research will develop an approach that defines an acceptable method for demonstrating compliance of decommissioned NPP sites and validates that compliance. Soil samples from NPP often contain censored data. Conventional methods for dealing with censored data sets are statistically biased and limited in their usefulness. In this research, additional methods are performed using real data from a monazite manufacturing factory.

Seismic Instrumentation Placement Recommendations Report

International Nuclear Information System (INIS)

Kennedy, W.N.

1998-01-01

DOE Order 420.1, ''Facility Safety'', requires that facilities or sites with hazardous materials be provided with instrumentation or other means to detect and record the occurrences and severity of seismic events. These requirements assure that necessary records are available after an earthquake for evaluation purposes and to supplement other data to justify a facility restart or curtailing plant operations after an earthquake. This report documents the basis for the selection of Savannah River Site areas and existing facilities to be instrumented. The need to install instrumentation in new facilities such as the Actinide Packaging and Storage Facility, Commercial Light Water Reactor Tritium Extraction Facility and the Accelerator Production of Tritium Facility will be assessed separately

LAMMA 500 principle and technical description of the instrument

International Nuclear Information System (INIS)

Vogt, H.; Heinen, H.J.; Meier, S.; Wechsung, R.

1981-01-01

The Laser Microprobe Mass Analyzer LAMMA 500 originally had been designed for the analysis of biomedical samples, especially thin sections, with high lateral resolution and extreme detection sensitivity. The principle of LAMMA is based on the excitation of a microvolume of the sample to an ionized state by a focused laser beam. The analytical information is derived from mass spectrometry of these ions. It is obvious that all elements of the periodic table and their isotopes can be detected. Various applications have demonstrated that besides element detection the instrument can also be used for the detection of organic and inorganic compounds. A detailed description of the LAMMA 500 instrument is given. (orig./RB)

Instrumental neutron-activation determination of impurities in lead and titanium compounds

Energy Technology Data Exchange (ETDEWEB)

Popova, I L

1980-01-01

Instrumental neutron-activation analysis was used to determine 22 impurities in lead and titanium compounds (e.g. PbO, Pb/NO3/2, and TiO2) used as raw materials for ferroelectrics. Five elements (Al, V, Mn, Sc, and Se) were determined by short-lived isotopes and 17 elements were determined by long-lived isotopes. The detection limits were 7 x 10 to the -3rd to 2 x 10 to the -8th %. A substantial difference in concentrations of certain impurity elements has been found in different series of lead and titanium oxides of similar purity.

Thermal ionization mass spectrometry (TIMS) of actinides: Pushing the limits of accuracy and detection

Energy Technology Data Exchange (ETDEWEB)

Buerger, Stefan; Boulyga, Sergei; Cunningham, Alan; Klose, Dilani; Koepf, Andreas; Poths, Jane [Safeguards Analytical Laboratory, International Atomic Energy Agency, Vienna (Austria); Richter, Stephan [Institute for Reference Materials and Measurements, JRC-EU, Geel (Belgium)

2010-07-01

New method developments in multi-collector thermal ionization mass spectrometry (MC-TIMS) for actinide isotope ratio analysis to improve accuracy and limits of detection will be presented. With respect to limits of detection, results on improving work function using various carbon additives will be reviewed and presented as well as developments in cavity ion source (as compared to standard flat ribbon filament ion source) for femto- and attogram levels of uranium, plutonium, and americium. With respect to accuracy, results on isotope ratio measurements of isotopes of uranium (relative accuracy of 0.3% to 0.01%) are presented with an example being U-234-Th-230 age-dating (NBL CRM 112-A). In this context, the importance of traceability (to the S.I. units) and the use of (certified) reference materials are emphasized. The focus of this presentation is on applications to nuclear safeguards / forensics.

Flexible Modeling of Survival Data with Covariates Subject to Detection Limits via Multiple Imputation.

Science.gov (United States)

Bernhardt, Paul W; Wang, Huixia Judy; Zhang, Daowen

2014-01-01

Models for survival data generally assume that covariates are fully observed. However, in medical studies it is not uncommon for biomarkers to be censored at known detection limits. A computationally-efficient multiple imputation procedure for modeling survival data with covariates subject to detection limits is proposed. This procedure is developed in the context of an accelerated failure time model with a flexible seminonparametric error distribution. The consistency and asymptotic normality of the multiple imputation estimator are established and a consistent variance estimator is provided. An iterative version of the proposed multiple imputation algorithm that approximates the EM algorithm for maximum likelihood is also suggested. Simulation studies demonstrate that the proposed multiple imputation methods work well while alternative methods lead to estimates that are either biased or more variable. The proposed methods are applied to analyze the dataset from a recently-conducted GenIMS study.

Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles

Science.gov (United States)

Nirala, Narsingh R.; Saxena, Preeti S.; Srivastava, Anchal

2018-02-01

We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2 mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19 mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100 mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel.

Multimodality instrument for tissue characterization

Science.gov (United States)

Mah, Robert W. (Inventor); Andrews, Russell J. (Inventor)

2004-01-01

A system with multimodality instrument for tissue identification includes a computer-controlled motor driven heuristic probe with a multisensory tip. For neurosurgical applications, the instrument is mounted on a stereotactic frame for the probe to penetrate the brain in a precisely controlled fashion. The resistance of the brain tissue being penetrated is continually monitored by a miniaturized strain gauge attached to the probe tip. Other modality sensors may be mounted near the probe tip to provide real-time tissue characterizations and the ability to detect the proximity of blood vessels, thus eliminating errors normally associated with registration of pre-operative scans, tissue swelling, elastic tissue deformation, human judgement, etc., and rendering surgical procedures safer, more accurate, and efficient. A neural network program adaptively learns the information on resistance and other characteristic features of normal brain tissue during the surgery and provides near real-time modeling. A fuzzy logic interface to the neural network program incorporates expert medical knowledge in the learning process. Identification of abnormal brain tissue is determined by the detection of change and comparison with previously learned models of abnormal brain tissues. The operation of the instrument is controlled through a user friendly graphical interface. Patient data is presented in a 3D stereographics display. Acoustic feedback of selected information may optionally be provided. Upon detection of the close proximity to blood vessels or abnormal brain tissue, the computer-controlled motor immediately stops probe penetration. The use of this system will make surgical procedures safer, more accurate, and more efficient. Other applications of this system include the detection, prognosis and treatment of breast cancer, prostate cancer, spinal diseases, and use in general exploratory surgery.

Power calculator for instrumental variable analysis in pharmacoepidemiology.

Science.gov (United States)

Walker, Venexia M; Davies, Neil M; Windmeijer, Frank; Burgess, Stephen; Martin, Richard M

2017-10-01

Instrumental variable analysis, for example with physicians' prescribing preferences as an instrument for medications issued in primary care, is an increasingly popular method in the field of pharmacoepidemiology. Existing power calculators for studies using instrumental variable analysis, such as Mendelian randomization power calculators, do not allow for the structure of research questions in this field. This is because the analysis in pharmacoepidemiology will typically have stronger instruments and detect larger causal effects than in other fields. Consequently, there is a need for dedicated power calculators for pharmacoepidemiological research. The formula for calculating the power of a study using instrumental variable analysis in the context of pharmacoepidemiology is derived before being validated by a simulation study. The formula is applicable for studies using a single binary instrument to analyse the causal effect of a binary exposure on a continuous outcome. An online calculator, as well as packages in both R and Stata, are provided for the implementation of the formula by others. The statistical power of instrumental variable analysis in pharmacoepidemiological studies to detect a clinically meaningful treatment effect is an important consideration. Research questions in this field have distinct structures that must be accounted for when calculating power. The formula presented differs from existing instrumental variable power formulae due to its parametrization, which is designed specifically for ease of use by pharmacoepidemiologists. © The Author 2017. Published by Oxford University Press on behalf of the International Epidemiological Association

Developing methods for detecting radioactive scrap

International Nuclear Information System (INIS)

Bellian, J.G.; Johnston, J.G.

1995-01-01

During the last 10 years, there have been major developments in radiation detection systems used for catching shielded radioactive sources in scrap metal. The original testing required to determine the extent of the problem and the preliminary designs of the first instruments will be discussed. Present systems available today will be described listing their advantages and disadvantages. In conclusion, the newest developments and state of the art equipment will also be included describing the limits and most appropriate locations for the systems

Evaluation on the detection limit of blood hemoglobin using photolepthysmography based on path-length optimization

Science.gov (United States)

Sun, Di; Guo, Chao; Zhang, Ziyang; Han, Tongshuai; Liu, Jin

2016-10-01

The blood hemoglobin concentration's (BHC) measurement using Photoplethysmography (PPG), which gets blood absorption to near infrared light from the instantaneous pulse of transmitted light intensity, has not been applied to the clinical use due to the non-enough precision. The main challenge might be caused of the non-enough stable pulse signal when it's very weak and it often varies in different human bodies or in the same body with different physiological states. We evaluated the detection limit of BHC using PPG as the measurement precision level, which can be considered as a best precision result because we got the relative stable subject's pulse signals recorded by using a spectrometer with high signal-to-noise ratio (SNR) level, which is about 30000:1 in short term. Moreover, we optimized the used pathlength using the theory based on optimum pathlength to get a better sensitivity to the absorption variation in blood. The best detection limit was evaluated as about 1 g/L for BHC, and the best SNR of pulse for in vivo measurement was about 2000:1 at 1130 and 1250 nm. Meanwhile, we conclude that the SNR of pulse signal should be better than 400:1 when the required detection limit is set to 5 g/L. Our result would be a good reference to the BHC measurement to get a desired BHC measurement precision of real application.

Limits on surface gravities of Kepler planet-candidate host stars from non-detection of solar-like oscillations

Energy Technology Data Exchange (ETDEWEB)

Campante, T. L.; Chaplin, W. J.; Handberg, R.; Miglio, A.; Davies, G. R.; Elsworth, Y. P. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lund, M. N.; Arentoft, T.; Christensen-Dalsgaard, J.; Karoff, C.; Kjeldsen, H.; Lundkvist, M. [Stellar Astrophysics Centre (SAC), Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Huber, D. [NASA Ames Research Center, MS 244-30, Moffett Field, CA 94035 (United States); Hekker, S. [Astronomical Institute, " Anton Pannekoek," University of Amsterdam, Amsterdam (Netherlands); García, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot (France); IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Corsaro, E. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Basu, S. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Bedding, T. R. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney (Australia); Gilliland, R. L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Kawaler, S. D., E-mail: campante@bison.ph.bham.ac.uk [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); and others

2014-03-10

We present a novel method for estimating lower-limit surface gravities (log g) of Kepler targets whose data do not allow the detection of solar-like oscillations. The method is tested using an ensemble of solar-type stars observed in the context of the Kepler Asteroseismic Science Consortium. We then proceed to estimate lower-limit log g for a cohort of Kepler solar-type planet-candidate host stars with no detected oscillations. Limits on fundamental stellar properties, as provided by this work, are likely to be useful in the characterization of the corresponding candidate planetary systems. Furthermore, an important byproduct of the current work is the confirmation that amplitudes of solar-like oscillations are suppressed in stars with increased levels of surface magnetic activity.

Detection Limits for Nanoscale Biosensors

National Research Council Canada - National Science Library

Sheehan, Paul E; Whitman, Lloyd J

2005-01-01

We examine through analytical calculations and finite element simulations how the detection efficiency of disk and wire-like biosensors in unmixed fluids varies with size from the micrometer to nanometer scales...

The Development of an Instrument to Measure the Work Capability of People with Limited Work Capacity (LWC).

Science.gov (United States)

van Ruitenbeek, Gemma M C; Zijlstra, Fred R H; Hülsheger, Ute R

2018-06-04

Purpose Participation in regular paid jobs positively affects mental and physical health of all people, including people with limited work capacities (LWC), people that are limited in their work capacity as a consequence of their disability, such as chronic mental illness, psychological or developmental disorder. For successful participation, a good fit between on one hand persons' capacities and on the other hand well-suited individual support and a suitable work environment is necessary in order to meet the demands of work. However, to date there is a striking paucity of validated measures that indicate the capability to work of people with LWC and that outline directions for support that facilitate the fit. Goal of the present study was therefore to develop such an instrument. Specifically, we adjusted measures of mental ability, conscientiousness, self-efficacy, and coping by simplifying the language level of these measures to make the scales accessible for people with low literacy. In order to validate these adjusted self-report and observer measures we conducted two studies, using multi-source, longitudinal data. Method Study 1 was a longitudinal multi-source study in which the newly developed instrument was administered twice to people with LWC and their significant other. We statistically tested the psychometric properties with respect to dimensionality and reliability. In Study 2, we collected new multi-source data and conducted a confirmatory factor analysis (CFA). Results Studies yielded a congruous factor structure in both samples, internally consistent measures with adequate content validity of scales and subscales, and high test-retest reliability. The CFA confirmed the factorial validity of the scales. Conclusion The adjusted self-report and the observer scales of mental ability, conscientiousness, self-efficacy, and coping are reliable measures that are well-suited to assess the work capability of people with LWC. Further research is needed to

Sensor and instrumentation for progesterone detection

KAUST Repository

Zia, Asif I.

2012-05-01

The reported research work uses a real time and noninvasive method to detect progesterone hormone concentration in purified water using Electrochemical Impedance Spectroscopy (E.I.S.) technique. Planar capacitive sensor, consisting of inter-digitated microelectrodes, is designed and fabricated on silicon substrate using thin-film Microelectromechanical system (MEMS) based semiconductor device fabrication technology. The sensor in conjunction with EIS is used to evaluate conductivity, permeability and dielectric properties of reproductive hormone progesterone and its concentration quantification in purified water. Impedance spectrums are obtained with various concentrations of the hormone in purified water by using an electric circuit in order to extract sample conductance. Relationship of sample conductance with progesterone concentration level is studied in this research work. The ability of E.I.S. to detect progesterone concentration is aimed to be used in dairy farming industry in order to obtain better reproductive performance of the dairy cattle. © 2012 IEEE.

Sensor and instrumentation for progesterone detection

KAUST Repository

Zia, Asif I.; Mohd. Syaifudin, A. R.; Mukhopadhyay, Subhas Chandra; Yu, Paklam; Al-Bahadly, Ibrahim H.; Kosel, Jü rgen; Gooneratne, Chinthaka Pasan

2012-01-01

The reported research work uses a real time and noninvasive method to detect progesterone hormone concentration in purified water using Electrochemical Impedance Spectroscopy (E.I.S.) technique. Planar capacitive sensor, consisting of inter-digitated microelectrodes, is designed and fabricated on silicon substrate using thin-film Microelectromechanical system (MEMS) based semiconductor device fabrication technology. The sensor in conjunction with EIS is used to evaluate conductivity, permeability and dielectric properties of reproductive hormone progesterone and its concentration quantification in purified water. Impedance spectrums are obtained with various concentrations of the hormone in purified water by using an electric circuit in order to extract sample conductance. Relationship of sample conductance with progesterone concentration level is studied in this research work. The ability of E.I.S. to detect progesterone concentration is aimed to be used in dairy farming industry in order to obtain better reproductive performance of the dairy cattle. © 2012 IEEE.

Picomolar detection limits with current-polarized Pb2+ ion-selective membranes.

Science.gov (United States)

Pergel, E; Gyurcsányi, R E; Tóth, K; Lindner, E

2001-09-01

Minor ion fluxes across ion-selective membranes bias submicromolar activity measurements with conventional ion-selective electrodes. When ion fluxes are balanced, the lower limit of detection is expected to be dramatically improved. As proof of principle, the flux of lead ions across an ETH 5435 ionophore-based lead-selective membrane was gradually compensated by applying a few nanoamperes of galvanostatic current. When the opposite ion fluxes were matched, and the undesirable leaching of primary ions was eliminated, Nernstian response down to 3 x 10(-12) M was achieved.

Use of a brief standardized screening instrument in a primary care setting to enhance detection of social-emotional problems among youth in foster care.

Science.gov (United States)

Jee, Sandra H; Halterman, Jill S; Szilagyi, Moira; Conn, Anne-Marie; Alpert-Gillis, Linda; Szilagyi, Peter G

2011-01-01

To determine whether systematic use of a validated social-emotional screening instrument in a primary care setting is feasible and improves detection of social-emotional problems among youth in foster care. Before-and-after study design, following a practice intervention to screen all youth in foster care for psychosocial problems using the Strengths and Difficulties Questionnaire (SDQ), a validated instrument with 5 subdomains. After implementation of systematic screening, youth aged 11 to 17 years and their foster parents completed the SDQ at routine health maintenance visits. We assessed feasibility of screening by measuring the completion rates of SDQ by youth and foster parents. We compared the detection of psychosocial problems during a 2-year period before systematic screening to the detection after implementation of systematic screening with the SDQ. We used chart reviews to assess detection at baseline and after implementing systematic screening. Altogether, 92% of 212 youth with routine visits that occurred after initiation of screening had a completed SDQ in the medical record, demonstrating high feasibility of systematic screening. Detection of a potential mental health problem was higher in the screening period than baseline period for the entire population (54% vs 27%, P youth had 2 or more significant social-emotional problem domains on the SDQ. Systematic screening for potential social-emotional problems among youth in foster care was feasible within a primary care setting and doubled the detection rate of potential psychosocial problems. Copyright © 2011 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Optofluidic analysis system for amplification-free, direct detection of Ebola infection

Science.gov (United States)

Cai, H.; Parks, J. W.; Wall, T. A.; Stott, M. A.; Stambaugh, A.; Alfson, K.; Griffiths, A.; Mathies, R. A.; Carrion, R.; Patterson, J. L.; Hawkins, A. R.; Schmidt, H.

2015-09-01

The massive outbreak of highly lethal Ebola hemorrhagic fever in West Africa illustrates the urgent need for diagnostic instruments that can identify and quantify infections rapidly, accurately, and with low complexity. Here, we report on-chip sample preparation, amplification-free detection and quantification of Ebola virus on clinical samples using hybrid optofluidic integration. Sample preparation and target preconcentration are implemented on a PDMS-based microfluidic chip (automaton), followed by single nucleic acid fluorescence detection in liquid-core optical waveguides on a silicon chip in under ten minutes. We demonstrate excellent specificity, a limit of detection of 0.2 pfu/mL and a dynamic range of thirteen orders of magnitude, far outperforming other amplification-free methods. This chip-scale approach and reduced complexity compared to gold standard RT-PCR methods is ideal for portable instruments that can provide immediate diagnosis and continued monitoring of infectious diseases at the point-of-care.

Instrument accuracy in reactor vessel inventory tracking systems

International Nuclear Information System (INIS)

Anderson, J.L.; Anderson, R.L.; Morelock, T.C.; Hauang, T.L.; Phillips, L.E.

1986-01-01

Instrumentation needs for detection of inadequate core cooling. Studies of the Three Mile Island accident identified the need for additional instrumentation to detect inadequate core cooling (ICC) in nuclear power plants. Industry studies by plant owners and reactor vendors supported the conclusion that improvements were needed to help operators diagnose the approach to or existence of ICC as well as to provide more complete information for operator control of safety injection flow to minimize the consequences of such an accident. In 1980, the US Nuclear Regulatory Commission (NRC) required further studies by the industry and described ICC instrumentation design requirements that included human factors and environmental considerations. On December 10, 1982, NRC issued to Babcock and Wilcox (B and W) licensees orders for Modification of License and transmitted to pressurized water reactor licensees Generic Letter 82-28 to inform them of the revised NRC requirements. The instrumentation requirements include upgraded subcooling margin monitors (SMM), upgraded core exit thermocouples (CET), and installation of a reactor coolant inventory tracking system. NRC Regulatory Guide 1.97, which covers accident monitoring instrumentation, was revised (Rev. 3) to be consistent with the requirements of item II.F.2 of NUREG-0737

July 1974 solar events: a possible lower limit for microwave activity

Energy Technology Data Exchange (ETDEWEB)

Kaufmann, P; Iacomo, P Jr; Koppe, E H; Marques dos Santos, P; Schaal, R E [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia e Astrofisica; Blakey, J R [Surrey Univ., Guildford (UK). Dept. of Physics

1975-11-01

The active region McMath 10433 was the source of several flares and radio outbursts during the early part of July 1974. This region was tracked continuously, for several periods during the month at 22.2 GHz using a telescope with a 4 minutes of arc beam. Comparison with the results obtained simultaneously with a normal 7 GHz solar instrument indicate that there is important burst activity occurring at levels below the detection limit of normal solar patrol instruments. The time-development morphology of these bursts is similar to those normally observed and has enabled the simple events to be re-interpreted. A completely new type of event-the fast absorption-has also been recognized. The correlation of the microwave events with SPA events observed on VLF propagation is also discussed.

Cellular telephone-based wide-area radiation detection network

Science.gov (United States)

Craig, William W [Pittsburg, CA; Labov, Simon E [Berkeley, CA

2009-06-09

A network of radiation detection instruments, each having a small solid state radiation sensor module integrated into a cellular phone for providing radiation detection data and analysis directly to a user. The sensor module includes a solid-state crystal bonded to an ASIC readout providing a low cost, low power, light weight compact instrument to detect and measure radiation energies in the local ambient radiation field. In particular, the photon energy, time of event, and location of the detection instrument at the time of detection is recorded for real time transmission to a central data collection/analysis system. The collected data from the entire network of radiation detection instruments are combined by intelligent correlation/analysis algorithms which map the background radiation and detect, identify and track radiation anomalies in the region.

Radiation measuring instrument

International Nuclear Information System (INIS)

Genrich, V.

1985-01-01

A highly sensitive and compactly structured radiation measuring instrument for detecting ionizing radiation, in particular for measuring dose rates and contamination. The laminar structure of the associated counter tube, using only a few, simple plastic parts and a highly elastic counter wire, makes it possible to use the simplest manufacturing techniques. The service life of the counter tube construction, which is completely and permanently sealed and filled with gas, is expected to be more than 12 years. The described counter tube can be adapted in optimal fashion to the available space in a pocket instrument if it is used in combination with a specialized high-voltage generator which is low in interference voltage and with a pulse evaluation circuit having a means of compensating for interference voltage

The study on the lidar's detection limit for Iodine Gas

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong-lyul; Baik, Seung-Hoon; Park, Seung-Kyu; Park, Nak-Gyu; Ahn, Yong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

A powerful and reliable tool for range-resolved remote sensing of gas concentrations that has proven its capabilities in a variety of studies is the differential absorption lidar (DIAL). Differential absorption lidar (DIAL) is frequently used for atmospheric gas monitoring to detect impurities such as nitrogen dioxide, sulfur dioxide, iodine, and ozone. DIAL can measure air pollutant concentrations with a high spatial resolution by adopting two laser systems with different degrees of absorption between the two different wavelengths. The absorption of the reference wavelength is very weak, while the absorption of the other wavelength is very strong. In this paper, we measured the limit of detection capability of our designed DIAL system. The DIAL measurements were performed using a target iodine cell in the laboratory. We confirmed that the concentration of iodine gas ratio increased after the laser passed through the iodine cell. The system of DIAL(Differential Absorption Lidar) was effective to detect the iodine gas. We obtained the signals from the iodine target cell and the lidar signal from the iodine target cell was proportional to frequency locking ratios.

First direct detection limits on sub-GeV dark matter from XENON10.

Science.gov (United States)

Essig, Rouven; Manalaysay, Aaron; Mardon, Jeremy; Sorensen, Peter; Volansky, Tomer

2012-07-13

The first direct detection limits on dark matter in the MeV to GeV mass range are presented, using XENON10 data. Such light dark matter can scatter with electrons, causing ionization of atoms in a detector target material and leading to single- or few-electron events. We use 15  kg day of data acquired in 2006 to set limits on the dark-matter-electron scattering cross section. The strongest bound is obtained at 100 MeV where σ(e)dark-matter masses between 20 MeV and 1 GeV are bounded by σ(e)dark-matter candidates with masses well below the GeV scale.

Energetic particles detected by the Electron Reflectometer instrument on the Mars Global Surveyor, 1999-2006

DEFF Research Database (Denmark)

Delory, Gregory T.; Luhmann, Janet G.; Brain, David

2012-01-01

events at Mars associated with solar flares and coronal mass ejections, which includes the identification of interplanetary shocks. MGS observations of energetic particles at varying geometries between the Earth and Mars that include shocks produced by halo, limb, and backsided events provide a unique......We report the observation of galactic cosmic rays and solar energetic particles by the Electron Reflectometer instrument aboard the Mars Global Surveyor (MGS) spacecraft from May of 1999 to the mission conclusion in November 2006. Originally designed to detect low-energy electrons, the Electron...... recorded high energy galactic cosmic rays with similar to 45% efficiency. Comparisons of this data to galactic cosmic ray proton fluxes obtained from the Advanced Composition Explorer yield agreement to within 10% and reveal the expected solar cycle modulation as well as shorter timescale variations. Solar...

Generation of Long-time Complex Signals for Testing the Instruments for Detection of Voltage Quality Disturbances

Science.gov (United States)

Živanović, Dragan; Simić, Milan; Kokolanski, Zivko; Denić, Dragan; Dimcev, Vladimir

2018-04-01

Software supported procedure for generation of long-time complex test sentences, suitable for testing the instruments for detection of standard voltage quality (VQ) disturbances is presented in this paper. This solution for test signal generation includes significant improvements of computer-based signal generator presented and described in the previously published paper [1]. The generator is based on virtual instrumentation software for defining the basic signal parameters, data acquisition card NI 6343, and power amplifier for amplification of output voltage level to the nominal RMS voltage value of 230 V. Definition of basic signal parameters in LabVIEW application software is supported using Script files, which allows simple repetition of specific test signals and combination of more different test sequences in the complex composite test waveform. The basic advantage of this generator compared to the similar solutions for signal generation is the possibility for long-time test sequence generation according to predefined complex test scenarios, including various combinations of VQ disturbances defined in accordance with the European standard EN50160. Experimental verification of the presented signal generator capability is performed by testing the commercial power quality analyzer Fluke 435 Series II. In this paper are shown some characteristic complex test signals with various disturbances and logged data obtained from the tested power quality analyzer.

Portable neutron and gamma-radiation instruments

International Nuclear Information System (INIS)

Murray, W.S.; Butterfield, K.B.

1990-01-01

This paper reports on the design and building of a smart neutron and gamma-radiation detection systems with embedded microprocessors programmed in the FORTH language. These portable instruments can be battery-powered and can provide many analysis functions not available in most radiation detectors. Local operation of the instruments is menu-driven through a graphics liquid crystal display and hex keypad; remote operation is through a serial communications link. While some instruments simply count particles, others determine the energy of the radiation as well as the intensity. The functions the authors have provided include absolute source-strength determination. Feynmann variance analysis, sequential-probability ratio test, and time-history recording

Provenance study of obsidian samples by using portable and conventional X ray fluorescence spectrometers. Performance comparison of both instrumentations

International Nuclear Information System (INIS)

Cristina Vazquez

2012-01-01

The potentiality of portable instrumentation lies on the possibility of the in situ determinations. Sampling, packaging and transport of samples from the site to the laboratory are avoided and the analysis becomes non destructive at all. However, detection limits for light elements are, in most cases, a limitation for quantification purposes. In this work a comparison between the results obtained with an X ray fluorescence spectrometer laboratory based and a portable instrument is performed. A set of 76 obsidian archaeological specimens from northwest Patagonia, Argentina was used to carry out the study. Samples were collected in the area of the middle and high basin of the Limay River. The analytical information obtained with both instrumentations was complemented with Principal Component Analysis in order to define groups and identify provenance sources. The information from both instruments allows arriving to the same conclusion about sample provenance and mobility of hunter-gatherer groups. Three groups of sources were identified in both cases matching with the geographical information. Also, same sets of outlier samples or not associated to these sources were found. Artifact samples were associated mainly to the closest sources, but some of them are related to sources located more than three hundred kilometers, evidencing the large mobility of the hunter-gatherers by the obsidian interchange. No significant differences between concentrations values obtained by laboratory based instrument and portable one were found. (author)

The ground fault detection system for the Tore Supra toroidal pump limiter

International Nuclear Information System (INIS)

Zunino, K.; Cara, P.; Fejoz, P.; Hourtoule, J.; Loarer, T.; Pomaro, N.; Santagiustina, A.; Spuig, P.; Villecroze, F.

2003-01-01

The toroidal pump limiter (TPL) of Tore Supra is electrically insulated from the vacuum-vessel, to allow its polarization at a voltage of up to 1 kV. In order to monitor continuously the integrity of the TPL electrical insulation, an electronic diagnostic system called TPL ground fault detection system (GFDS) has been developed. The paper will report on the design and the operation experience of the GFD system and on the evolution of the TPL grounding

Instrumentation for mass spectrometry: 1997

Energy Technology Data Exchange (ETDEWEB)

McLuckey, S.A.

1997-08-01

All mass spectrometry experiments involve the manipulation of material, an interface with the mass spectrometer, ionization, ion manipulation/analysis, detection and data collection/reduction. Each of these elements involve instrumentation. The wide range of species now amenable to mass spectrometry and the diverse areas of physical science in which it plays a role have led to a seemingly unlimited array of instrumental combinations. However, only a limited number of mass analyzers, and their combinations, dominate. The dominant analyzers include time-of-flight, Fourier transform ion cyclotron resonance, the Paul trap, the mass filter, and the sector mass spectrometer. Why there are so few (or so many, depending upon one`s point of view) can be understood upon consideration of a set of mass analyzer figures of merit. These include mass resolution, mass accuracy, mass range, dynamic range, abundance sensitivity, precision, efficiency, speed, MS{sup n} capability, compatibility with the ionizer, cost, and size. The most appropriate form of mass spectrometry is determined by the priorities of the particular measurement placed on the various mass analyzer characteristics and the relative strengths of the analyzers in meeting the requirements. Each of the analyzer types has a unique set of figures of merit that makes it optimally suited for particular applications. This paper discusses these figures of merit, provides data illustrating recent developments for each analyzer type, and gives the figures of merit of each type of analyzer as they stand in 1997. 101 refs., 24 figs.

Development of smart nuclear instrumentation for reactors

International Nuclear Information System (INIS)

Chaganty, S.P.; Das, D.; Bhatnagar, P.V.; Das, A.; Sreedharan, Preetha; Kataria, S.K.

2001-01-01

Variety of nuclear instruments are required for different applications in reactors such as reactor start-up, reactor protection and regulating system, area monitoring, failed fuel detection, stack monitoring etc. Attempts are made to develop a standardized microcomputer based hardware for configuring different types of instruments. PC architecture is chosen due to easy availability of components/boards and software. These instruments have dual redundant Network Interface Cards for connecting to a Primary Radiation Data LAN which in turn can be connected to Plant Information Bus through Gateways. These SMART instruments can be tested/calibrated through specific commands from remote computers connected over the LAN. This paper describes the various issues involved and the design details. (author)

Creating a Super Instrument

DEFF Research Database (Denmark)

Kallionpää, Maria; Gasselseder, Hans-Peter

2015-01-01

Thanks to the development of new technology, musical instruments are no more tied to their existing acoustic or technical limitations as almost all parameters can be augmented or modified in real time. An increasing number of composers, performers, and computer programmers have thus become intere...

Indigenous instrumentation for mass spectrometry: Part II - development of plasma source mass spectrometers. PD-5-3

International Nuclear Information System (INIS)

Nataraju, V.

2007-01-01

The growing demands from analytical community, for a precise isotope ratio and ultra trace concentration measurements, has lead to significant improvement in mass spectrometer instrumentation development with respect to sensitivity, detection limits, precision and accuracy. Among the many analytical techniques available, plasma source mass spectrometers like Inductively Coupled Plasma Mass Spectrometry (ICPMS), multi collector (MC) ICPMS and Glow Discharge Mass Spectrometry (GDMS), have matured into reliable tools for the above applications. Where as ICPMS is by far the most successful method for aqueous solutions, GDMS is being applied for bulk and impurity analysis of conducting as well non-conducting solids. VPID, BARC has been developing mass spectrometers for different inorganic applications of DAE users. Over the years expertise has been developed in all the aspects of mass spectrometry instrumentation. Part 1 of this indigenous instrumentation on mass spectrometry gives details of magnetic sector instruments with either EI or TI source for isotopic ratio analysis. The present paper is a continuation of that on plasma source and quadrupole mass spectrometers. This paper covers i) ICP-QMS, ii) MC-ICPMS, iii) GDMS and iv) QMS

Sensors and Instrumentation towards early detection of osteoporosis

KAUST Repository

Afsarimanesh, Nasrin; Mukhopadhyay, Subhas C; Kruger, Marlena; Yu, Pak-Lam; Kosel, Jü rgen

2016-01-01

A label-free non-invasive sensing system for detection of C-terminal telopeptide of type-I collagen (CTX-I) has been developed in order to detect bone loss at an early stage, by Electrochemical Impedance Spectroscopy (EIS). A planar interdigital

Method for evaluating the system instrumentation for loose part detection in the primary cooling circuit of French PWRs

International Nuclear Information System (INIS)

Gerardin, J.P.; Donnette, J.E.

1995-05-01

The purpose of the loose part detection system is to trigger an alarm whenever it is warranted, to localize, and to provide information on the type of loose part involved and the damages it may provoke. It is therefore indispensable to have efficient instrumentation, beginning with the sensors which must provide us with a response to all mechanical impacts in natural trapping areas (reactor vessel and steam generator water box). A series of mass- and energy-calibrated impacts have been generated on 45 points in the primary cooling system of a nuclear plant unit in the startup phase. This test provided insights into the relationship between sensor signals and various impact parameters such as velocity of impact or loose part mass. Once these parameters were known, it was possible to define a method for evaluating the detection threshold of sensors depending on the way they are mounted. (author)

Physiological techniques for detecting expiratory flow limitation during tidal breathing

Directory of Open Access Journals (Sweden)

N.G. Koulouris

2011-09-01

Full Text Available Patients with severe chronic obstructive pulmonary disease (COPD often exhale along the same flow–volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFLT. Therefore, EFLT, namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFLT leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFLT occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage, in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFLT are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique.

Upper limits on gravitational wave bursts in LIGO's second science run

International Nuclear Information System (INIS)

Abbott, B.; Adhikari, R.; Agresti, J.; Anderson, S.B.; Araya, M.; Armandula, H.; Asiri, F.; Barish, B.C.; Barnes, M.; Barton, M.A.; Bhawal, B.; Billingsley, G.; Black, E.; Blackburn, K.; Bork, R.; Brown, D.A.; Busby, D.; Cardenas, L.; Chandler, A.; Chapsky, J.

2005-01-01

We perform a search for gravitational wave bursts using data from the second science run of the LIGO detectors, using a method based on a wavelet time-frequency decomposition. This search is sensitive to bursts of duration much less than a second and with frequency content in the 100-1100 Hz range. It features significant improvements in the instrument sensitivity and in the analysis pipeline with respect to the burst search previously reported by LIGO. Improvements in the search method allow exploring weaker signals, relative to the detector noise floor, while maintaining a low false alarm rate, O(0.1) μHz. The sensitivity in terms of the root-sum-square (rss) strain amplitude lies in the range of h rss ∼10 -20 -10 -19 Hz -1/2 . No gravitational wave signals were detected in 9.98 days of analyzed data. We interpret the search result in terms of a frequentist upper limit on the rate of detectable gravitational wave bursts at the level of 0.26 events per day at 90% confidence level. We combine this limit with measurements of the detection efficiency for selected waveform morphologies in order to yield rate versus strength exclusion curves as well as to establish order-of-magnitude distance sensitivity to certain modeled astrophysical sources. Both the rate upper limit and its applicability to signal strengths improve our previously reported limits and reflect the most sensitive broad-band search for untriggered and unmodeled gravitational wave bursts to date

Calibration of the Fluorine, Chlorine and Hydrogen Content of Apatites With the ChemCam LIBS Instrument

Science.gov (United States)

Meslin, P.-Y.; Cicutto, L.; Forni, O.; Drouet, C.; Rapin, W.; Nachon, M.; Cousin, A.; Blank, J. G.; McCubbin, F. M.; Gasnault, O.;

Diamond-based electrochemical aptasensor realizing a femtomolar detection limit of bisphenol A.

Science.gov (United States)

Ma, Yibo; Liu, Junsong; Li, Hongdong

2017-06-15

In this study, we designed and fabricated an electrochemical impedance aptasensor based on Au nanoparticles (Au-NPs) coated boron-doped diamond (BDD) modified with aptamers, and 6-mercapto-1-hexanol (MCH) for the detection of bisphenol A (BPA). The constructed BPA aptasensor exhibits good linearity from 1.0×10 -14 to 1.0×10 -9 molL -1 . The detection limitation of 7.2×10 -15 molL -1 was achieved, which can be attributed to the synergistic effect of combining BDD with Au-NPs, aptamers, and MCH. The examine results of BPA traces in Tris-HCl buffer and in milk, UV spectra of aptamer/BPA and interference test revealed that the novel aptasensors are of high sensitivity, specificity, stability and repeatability, which could be promising in practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Improved sensitivity and limit-of-detection of lateral flow devices using spatial constrictions of the flow-path.

Science.gov (United States)

Katis, Ioannis N; He, Peijun J W; Eason, Robert W; Sones, Collin L

2018-05-03

We report on the use of a laser-direct write (LDW) technique that allows the fabrication of lateral flow devices with enhanced sensitivity and limit of detection. This manufacturing technique comprises the dispensing of a liquid photopolymer at specific regions of a nitrocellulose membrane and its subsequent photopolymerisation to create impermeable walls inside the volume of the membrane. These polymerised structures are intentionally designed to create fluidic channels which are constricted over a specific length that spans the test zone within which the sample interacts with pre-deposited reagents. Experiments were conducted to show how these constrictions alter the fluid flow rate and the test zone area within the constricted channel geometries. The slower flow rate and smaller test zone area result in the increased sensitivity and lowered limit of detection for these devices. We have quantified these via the improved performance of a C-Reactive Protein (CRP) sandwich assay on our lateral flow devices with constricted flow paths which demonstrate an improvement in its sensitivity by 62x and in its limit of detection by 30x when compared to a standard lateral flow CRP device. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Limit of detection for the determination of Pt in biological material by RNAA using electrolytic separation of gold

International Nuclear Information System (INIS)

Xilei, L.; Heydorn, K.; Rietz, B.

1992-01-01

Neutron activation analysis based on the 199 Au indicator for platinum requires the separation of gold at high radiochemical purity. The limit of detection is strongly affected by the presence of gold; with a gold content of 50 pg/g, irradiating for 5 days at 5*10 13 n/cm 2 is needed to achieve a limit of detection of approximately 30 pg/g. In this case the nuclear interference from gold will exceeded the level of platium by several orders of magnitude and has to be determined with exceedingly high precision. Preliminary results for SRM 1577 Bovine Liver with 95% yield gave consistent results for Au, but Pt could not be detected. (author) 23 refs.; 3 figs.; 4 tabs

Comparison of the Multiattribute Utility Instruments EQ-5D and SF-6D in a Europe-Wide Population-Based Cohort of Patients with Inflammatory Bowel Disease 10 Years after Diagnosis.

Science.gov (United States)

Huppertz-Hauss, Gert; Aas, Eline; Lie Høivik, Marte; Langholz, Ebbe; Odes, Selwyn; Småstuen, Milada; Stockbrugger, Reinhold; Hoff, Geir; Moum, Bjørn; Bernklev, Tomm

2016-01-01

Background. The treatment of chronic inflammatory bowel disease (IBD) is costly, and limited resources call for analyses of the cost effectiveness of therapeutic interventions. The present study evaluated the equivalency of the Short Form 6D (SF-6D) and the Euro QoL (EQ-5D), two preference-based HRQoL instruments that are broadly used in cost-effectiveness analyses, in an unselected IBD patient population. Methods. IBD patients from seven European countries were invited to a follow-up visit ten years after their initial diagnosis. Clinical and demographic data were assessed, and the Short Form 36 (SF-36) was employed. Utility scores were obtained by calculating the SF-6D index values from the SF-36 data for comparison with the scores obtained with the EQ-5D questionnaire. Results. The SF-6D and EQ-5D provided good sensitivities for detecting disease activity-dependent utility differences. However, the single-measure intraclass correlation coefficient was 0.58, and the Bland-Altman plot indicated numerous values beyond the limits of agreement. Conclusions. There was poor agreement between the measures retrieved from the EQ-5D and the SF-6D utility instruments. Although both instruments may provide good sensitivity for the detection of disease activity-dependent utility differences, the instruments cannot be used interchangeably. Cost-utility analyses performed with only one utility instrument must be interpreted with caution.

The instrumentation of fast reactor

International Nuclear Information System (INIS)

Endo, Akira

2003-03-01

The author has been engaged in the development of fast reactors over the last 30 years with both an involvement with the early technology development on the experimental breeder reactor Joyo, and latterly continuing this work on the prototype breeder reactor, Monju. In order to pass on this experience to younger engineers this paper is produced to outline this experience in the sincere hope that the information given will be utilised in future educational training material. The paper discusses the wide diversity on the associated instrument technology which the fast breeder reactor requires. The first chapter outlines the fast reactor system, followed by discussions on reactor instrumentation, measurement principles, temperature dependencies, and verification response characteristics from various viewpoints, are discussed in chapters two and three. The important issues of failed fuel location detection, and sodium leak detection from steam generators are discussed in chapters 4 and 5 respectively. Appended to this report is an explanation on the methods of measuring response characteristics on instrumentation systems using error analysis, random signal theory and measuring method of response characteristic by AR (autoregressive) model on which it appears is becoming an indispensable problem for persons involved with this technology in the future. (author)

Detection limits of pollutants in water for PGNAA using Am-Be source

International Nuclear Information System (INIS)

Khelifi, R.; Amokrane, A.; Bode, P.

2007-01-01

A basic PGNAA facility with an Am-Be neutron source is described to analyze the pollutants in water. The properties of neutron flux were determined by MCNP calculations. In order to determine the efficiency curve of a HPGe detector, the prompt-gamma rays from chlorine were used and an exponential curve was fitted. The detection limits for typical water sample are also estimated using the statistical fluctuations of the background level in the areas of recorded the prompt-gamma spectrum

Characteristics of protective instrumentation

International Nuclear Information System (INIS)

Reichart, G.

1982-01-01

Protective Instrumentation (PI) for Nuclear Power Plants (NPP) is a general term for an highly reliable instrumentation, which provides information for keeping the system within safe limits, for initation of countermeasures in the case of an incident or for mitigation of consequences of an accident. In German NPPs one can find a hierarchical structure of protective instrumentation, wherein the Reactor Protection System (RPS) has the highest priority. To meet the reliability requirements different design principles are used, like - redundancy - diversity - fail safe - decoupling. The presentation gives an overview about the different design principles and characterizes their reliability aspects. As an example for the technical realization the RPS of a German NPP is discussed in some detail. Furthermore some information about other type of PI is given and reliability aspects of the interaction of operating personell with these systems are mentioned. (orig.)

Simple Approaches to Minimally-Instrumented, Microfluidic-Based Point-of-Care Nucleic Acid Amplification Tests

Science.gov (United States)

Mauk, Michael G.; Song, Jinzhao; Liu, Changchun; Bau, Haim H.

2018-01-01

Designs and applications of microfluidics-based devices for molecular diagnostics (Nucleic Acid Amplification Tests, NAATs) in infectious disease testing are reviewed, with emphasis on minimally instrumented, point-of-care (POC) tests for resource-limited settings. Microfluidic cartridges (‘chips’) that combine solid-phase nucleic acid extraction; isothermal enzymatic nucleic acid amplification; pre-stored, paraffin-encapsulated lyophilized reagents; and real-time or endpoint optical detection are described. These chips can be used with a companion module for separating plasma from blood through a combined sedimentation-filtration effect. Three reporter types: Fluorescence, colorimetric dyes, and bioluminescence; and a new paradigm for end-point detection based on a diffusion-reaction column are compared. Multiplexing (parallel amplification and detection of multiple targets) is demonstrated. Low-cost detection and added functionality (data analysis, control, communication) can be realized using a cellphone platform with the chip. Some related and similar-purposed approaches by others are surveyed. PMID:29495424

Simple Approaches to Minimally-Instrumented, Microfluidic-Based Point-of-Care Nucleic Acid Amplification Tests

Directory of Open Access Journals (Sweden)

Michael G. Mauk

2018-02-01

Full Text Available Designs and applications of microfluidics-based devices for molecular diagnostics (Nucleic Acid Amplification Tests, NAATs in infectious disease testing are reviewed, with emphasis on minimally instrumented, point-of-care (POC tests for resource-limited settings. Microfluidic cartridges (‘chips’ that combine solid-phase nucleic acid extraction; isothermal enzymatic nucleic acid amplification; pre-stored, paraffin-encapsulated lyophilized reagents; and real-time or endpoint optical detection are described. These chips can be used with a companion module for separating plasma from blood through a combined sedimentation-filtration effect. Three reporter types: Fluorescence, colorimetric dyes, and bioluminescence; and a new paradigm for end-point detection based on a diffusion-reaction column are compared. Multiplexing (parallel amplification and detection of multiple targets is demonstrated. Low-cost detection and added functionality (data analysis, control, communication can be realized using a cellphone platform with the chip. Some related and similar-purposed approaches by others are surveyed.

Instrumental tactile diagnostics in robot-assisted surgery

Directory of Open Access Journals (Sweden)

Solodova RF

2016-10-01

Full Text Available Rozalia F Solodova,1,2 Vladimir V Galatenko,1,2 Eldar R Nakashidze,3 Igor L Andreytsev,3 Alexey V Galatenko,1 Dmitriy K Senchik,2 Vladimir M Staroverov,1 Vladimir E Podolskii,1,2 Mikhail E Sokolov,1,2 Victor A Sadovnichy1,2 1Faculty of Mechanics and Mathematics, 2Institute of Mathematical Studies of Complex Systems, Lomonosov Moscow State University, 31st Surgery Department, Clinical Hospital 31, Moscow, Russia Background: Robotic surgery has gained wide acceptance due to minimizing trauma in patients. However, the lack of tactile feedback is an essential limiting factor for the further expansion. In robotic surgery, feedback related to touch is currently kinesthetic, and it is mainly aimed at the minimization of force applied to tissues and organs. Design and implementation of diagnostic tactile feedback is still an open problem. We hypothesized that a sufficient tactile feedback in robot-assisted surgery can be provided by utilization of Medical Tactile Endosurgical Complex (MTEC, which is a novel specialized tool that is already commercially available in the Russian Federation. MTEC allows registration of tactile images by a mechanoreceptor, real-time visualization of these images, and reproduction of images via a tactile display. Materials and methods: Nine elective surgeries were performed with da Vinci™ robotic system. An assistant performed tactile examination through an additional port under the guidance of a surgeon during revision of tissues. The operating surgeon sensed registered tactile data using a tactile display, and the assistant inspected the visualization of tactile data. First, surgeries where lesion boundaries were visually detectable were performed. The goal was to promote cooperation between the surgeon and the assistant and to train them in perception of the tactile feedback. Then, instrumental tactile diagnostics was utilized in case of visually undetectable boundaries. Results: In robot-assisted surgeries where lesion

Endotoxins in surgical instruments of hip arthroplasty

Directory of Open Access Journals (Sweden)

Vania Regina Goveia

2016-06-01

Full Text Available Abstract OBJECTIVE To investigate endotoxins in sterilized surgical instruments used in hip arthroplasties. METHOD A descriptive exploratory study conducted in a public teaching hospital. Six types of surgical instruments were selected, namely: acetabulum rasp, femoral rasp, femoral head remover, chisel box, flexible bone reamer and femoral head test. The selection was based on the analysis of the difficulty in removing bone and blood residues during cleaning. The sample was made up of 60 surgical instruments, which were tested for endotoxins in three different stages. The EndosafeTM Gel-Clot LAL (Limulus Amebocyte Lysate method was used. RESULT There was consistent gel formation with positive analysis in eight instruments, corresponding to 13.3%, being four femoral rasps and four bone reamers. CONCLUSION Endotoxins in quantity ≥0.125 UE/mL were detected in 13.3% of the instruments tested.

Procedures and instrumentation for sodium boiling experiments in EBR-II

International Nuclear Information System (INIS)

Crowe, R.D.

1976-01-01

The development of instrumentation capable of detecting localized coolant boiling in a liquid metal cooled breeder reactor (LMFBR) has a high priority in fast reactor safety. The detection must be rapid enough to allow corrective action to be taken before significant damage occurs to the core. To develop and test a method of boiling detection, it is desirable to produce boiling in a reactor and thereby introduce a condition in the reactor the original design concepts were chosen to preclude. The proposed boiling experiments are designed to safely produce boiling in the subassembly of a fast reactor and provide the information to develop boiling detection instrumentation without core damage or safety compromise. The experiment consists of the operation of two separate subassemblies, first, a gamma heated boiling subassembly which produces non-typical but highly conservative boiling and then a fission heated subassembly which simulates a prototypical boiling event. The two boiling subassemblies are designed to operate in the instrumentation subassembly test facility (INSAT) of Experiment Breeder Reactor II

INTEGRAL/JEM-X detection of 1RXS J194211.9+255552

DEFF Research Database (Denmark)

Chenevez, Jérôme; Fiocchi, M.; Bazzano, A.

2011-01-01

exposure leading to a detection significance of eight sigmas. The averaged fluxes extracted from the combined JEM-X1 and JEM-X2 mosaics are 10 +/-2 mCrab and 16 +/-5 mCrab, between 3-10 keV and 10-25 keV, respectively. The source is not detected by the IBIS/ISGRI instrument, and we derive a 3-sigma flux...... upper limit of six mCrab in the 18-40 keV energy range. A Swift ToO follow-up has been approved and the data analysis will soon be performed....

Correlation of Michigan neuropathy screening instrument, United Kingdom screening test and electrodiagnosis for early detection of diabetic peripheral neuropathy.

Science.gov (United States)

Fateh, Hamid R; Madani, Seyed Pezhman; Heshmat, Ramin; Larijani, Bagher

2015-01-01

Almost half of Diabetic Peripheral Neuropathies (DPNs) are symptom-free. Methods including questionnaires and electrodiagnosis (EDx) can be fruitful for easy reach to early diagnosis, correct treatments of diabetic neuropathy, and so decline of complications for instance diabetic foot ulcer and prevention of high costs. The goal of our study was to compare effectiveness of the Michigan neuropathy screening instrument (MNSI), United Kingdom screening test (UKST) and electrophysiological evaluation in confirming diabetic peripheral neuropathy. One hundred twenty five known diabetes mellitus male and female subjects older than 18 with or without symptoms of neuropathy comprised in this research. All of them were interviewed in terms of demographic data, lipid profile, HbA1C, duration of disease, and history of retinopathy, so examined by Michigan neuropathy screening instrument (MNSI), United Kingdom screening test (UKST), and nerve conduction studies (NCS). The collected data were analyzed by SPSS software 18. One hundred twenty five diabetic patients (70 female, 55 male) were recruited in this study with a mean age of 58.7 ± 10.2, and mean duration of diabetes was 10.17 ± 6.9 years. The mean neuropathy score of MNSI and UKST were 2.3 (1.7) and 4.16 (2.9), respectively. Each instrument detected the peripheral neuropathy in 78 (69 %) and 91 (73 %) of patients, respectively. There was a significant relationship between number of neuropathies and mean of diabetes duration and development of retinopathy in both questionnaire evaluations and NCS. By nerve conduction study, neuropathy was detected in 121 (97 %) diabetic patients were reported in order 15 (12 %) mononeuropathy (as 33 % sensory and 67 % motor neuropathy) and 106 (85 %) polyneuropathy (as 31 % motor and 69 % sensorimotor neuropathy). As regards NCS is an objective, simple, and non-invasive tool and also can determine level of damage and regeneration in peripheral nerves, this study

Direct Detection Electron Energy-Loss Spectroscopy: A Method to Push the Limits of Resolution and Sensitivity.

Science.gov (United States)

Hart, James L; Lang, Andrew C; Leff, Asher C; Longo, Paolo; Trevor, Colin; Twesten, Ray D; Taheri, Mitra L

2017-08-15

In many cases, electron counting with direct detection sensors offers improved resolution, lower noise, and higher pixel density compared to conventional, indirect detection sensors for electron microscopy applications. Direct detection technology has previously been utilized, with great success, for imaging and diffraction, but potential advantages for spectroscopy remain unexplored. Here we compare the performance of a direct detection sensor operated in counting mode and an indirect detection sensor (scintillator/fiber-optic/CCD) for electron energy-loss spectroscopy. Clear improvements in measured detective quantum efficiency and combined energy resolution/energy field-of-view are offered by counting mode direct detection, showing promise for efficient spectrum imaging, low-dose mapping of beam-sensitive specimens, trace element analysis, and time-resolved spectroscopy. Despite the limited counting rate imposed by the readout electronics, we show that both core-loss and low-loss spectral acquisition are practical. These developments will benefit biologists, chemists, physicists, and materials scientists alike.

Pressure optimization of an EC-QCL based cavity ring-down spectroscopy instrument for exhaled NO detection

Science.gov (United States)

Zhou, Sheng; Han, Yanling; Li, Bincheng

2018-02-01

Nitric oxide (NO) in exhaled breath has gained increasing interest in recent years mainly driven by the clinical need to monitor inflammatory status in respiratory disorders, such as asthma and other pulmonary conditions. Mid-infrared cavity ring-down spectroscopy (CRDS) using an external cavity, widely tunable continuous-wave quantum cascade laser operating at 5.3 µm was employed for NO detection. The detection pressure was reduced in steps to improve the sensitivity, and the optimal pressure was determined to be 15 kPa based on the fitting residual analysis of measured absorption spectra. A detection limit (1σ, or one time of standard deviation) of 0.41 ppb was experimentally achieved for NO detection in human breath under the optimized condition in a total of 60 s acquisition time (2 s per data point). Diurnal measurement session was conducted for exhaled NO. The experimental results indicated that mid-infrared CRDS technique has great potential for various applications in health diagnosis.

New technology in nuclear power plant instrumentation and control

International Nuclear Information System (INIS)

Anon.

1985-01-01

The primary topic of this book is what can be done to improve nuclear power plant operation safety and the economic benefits that can be gained with the utilization of advance instrumentation and control technology. Other topics discussed are the industry's reluctance to accept new designs determining cost effective improvements, and difficulties in meeting regulatory standards with new technology control. The subjects will be useful when considering the area of instrumentation and control for enhancing plant operation and safety. Contents: Advanced Instrumention, Plant Control and Monitoring, Plant Diagnostics and Failure Detection, Human Factors Considerations in Instrumentation and Control, NRC and Industry Perspective on Advanced Instrumentation and Control

Derivative financial instruments and nonprofit health care providers.

Science.gov (United States)

Stewart, Louis J; Owhoso, Vincent

2004-01-01

This article examines the extent of derivative financial instrument use among US nonprofit health systems and the impact of these financial instruments on their cash flows, reported operating results, and financial risks. Our examination is conducted through a case study of New Jersey hospitals and health systems. We review the existing literature on interest rate derivative instruments and US hospitals and health systems. This literature describes the design of these derivative financial instruments and the theoretical benefits of their use by large health care provider organizations. Our contribution to the literature is to provide an empirical evaluation of derivative financial instruments usage among a geographically limited sample of US nonprofit health systems. We reviewed the audited financial statements of the 49 community hospitals and multi-hospital health systems operating in the state of New Jersey. We found that 8 percent of New Jersey's nonprofit health providers utilized interest rate derivatives with an aggregate principle value of $229 million. These derivative users combine interest rate swaps and caps to lower the effective interest costs of their long-term debt while limiting their exposure to future interest rate increases. In addition, while derivative assets and liabilities have an immaterial balance sheet impact, derivative related gains and losses are a material component of their reported operating results. We also found that derivative usage among these four health systems was responsible for generating positive cash flows in the range of 1 percent to 2 percent of their total 2001 cash flows from operations. As a result of our admittedly limited samples we conclude that interest rate swaps and caps are effective risk management tools. However, we also found that while these derivative financial instruments are useful hedges against the risks of issuing long-term financing instruments, they also expose derivative users to credit, contract

Laser-based instrumentation for the detection of chemical agents

International Nuclear Information System (INIS)

Hartford, A. Jr.; Sander, R.K.; Quigley, G.P.; Radziemski, L.J.; Cremers, D.A.

1982-01-01

Several laser-based techniques are being evaluated for the remote, point, and surface detection of chemical agents. Among the methods under investigation are optoacoustic spectroscopy, laser-induced breakdown spectroscopy (LIBS), and synchronous detection of laser-induced fluorescence (SDLIF). Optoacoustic detection has already been shown to be capable of extremely sensitive point detection. Its application to remote sensing of chemical agents is currently being evaluated. Atomic emission from the region of a laser-generated plasma has been used to identify the characteristic elements contained in nerve (P and F) and blister (S and Cl) agents. Employing this LIBS approach, detection of chemical agent simulants dispersed in air and adsorbed on a variety of surfaces has been achieved. Synchronous detection of laser-induced fluorescence provides an attractive alternative to conventional LIF, in that an artificial narrowing of the fluorescence emission is obtained. The application of this technique to chemical agent simulants has been successfully demonstrated. 19 figures

Toxic trace element content of local fruits using instrumental neutron activation analysis (INAA)

International Nuclear Information System (INIS)

Siddique, N.; Ahmed, S.; Rahman, A; Waheed, S.; Chaudhary, M.M.; Qureshi, I.H.

1997-01-01

An important route of entry of environmental contaminants into the human system is through food intake. To study the effect of environmental pollution on the food chain, base line levels of toxic element content of commonly available food articles must be established. This study was undertaken to determine the toxic meal content of Pakistani fruits. The techniques of instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometry (AAS) were employed for this purpose. Fourteen fruits apple, apricot, banana, data guava, kino, mango, melon, orange, peach, pear, plum, pomegranate and watermelon, as well as, the peels of apple and pear have been investigated and the results are discussed in this paper. The results were found to lie within 95 % confidence limit using Student's t test. Hg, As and Sb were detected, using INAA, in pear, pomegranate and water melon in low amounts (ppb levels) but were not detected in orange, plum and melon. Lesser amounts of toxic elements were detected in the peels of pear and high amounts were detected in apple peel as compared to the edible part of the fruit. Cadmium and lead were determined using Graphite Furnace atomic absorption Spectrometry. Cadmium was found to lie in the range of 18-42 ppb, in most fruits, whereas the amount of lead varied between 39-128 ppb. Lead was below detection limit in melon, guava, mango, and peach contained the highest amount of As, Cd, Hg and Pb. (author)

Innovative instrumentation for VVERs based in non-invasive techniques

International Nuclear Information System (INIS)

Jeanneau, H.; Favennec, J.M.; Tournu, E.; Germain, J.L.

2000-01-01

Nuclear power plants such as VVERs can greatly benefit from innovative instrumentation to improve plant safety and efficiency. In recent years innovative instrumentation has been developed for PWRs with the aim of providing additional measurements of physical parameters on the primary and secondary circuits: the addition of new instrumentation is made possible by using non-invasive techniques such as ultrasonics and radiation detection. These innovations can be adapted for upgrading VVERs presently in operation and also in future VVERs. The following innovative instrumentation for the control, monitoring or testing at VVERs is described: 1. instrumentation for more accurate primary side direct measurements (for a better monitoring of the primary circuit); 2. instrumentation to monitor radioactivity leaks (for a safer plant); 3. instrumentation-related systems to improve the plant efficiency (for a cheaper kWh)

ROBUST ESTIMATION OF MEAN AND VARIANCE USING ENVIRONMENTAL DATA SETS WITH BELOW DETECTION LIMIT OBSERVATIONS

Science.gov (United States)

Scientists, especially environmental scientists often encounter trace level concentrations that are typically reported as less than a certain limit of detection, L. Type 1, left-censored data arise when certain low values lying below L are ignored or unknown as they cannot be mea...

Some emergency instrumentation

Energy Technology Data Exchange (ETDEWEB)

Burgess, P H

1986-10-01

The widespread release of activity and the resultant spread of contamination after the Chernobyl accident resulted in requests to NRPB to provide instruments for, and expertise in, the measurement of radiation. The most common request was for advice on the usefulness of existing instruments, but Board staff were also involved in their adaptation or in the development of new instruments specially to meet the circumstances of the accident. The accident occurred on 26 April. On 1 May, NRPB was involved at Heathrow Airport in the monitoring of the British students who had returned from Kiev and Minsk. The main purpose was to reassure the students by checking that their persons and belongings did not have significant surface contamination. Additional measurements were also made of iodine activity in thyroid using hand-held detectors or a mobile body monitor. This operation was arranged with the Foreign and Commonwealth Office, which had also received numerous requests for instruments from embassies and consulates in countries close to the scene of the accident. There was concern for the well-being of staff and other United Kingdom nationals who resided in or intended to visit the most affected countries. The board supplied suitable instruments, and the FCO distributed them to embassies. The frequency of environmental monitoring was increased from 29 April in anticipation of contamination and appropriate Board instrumentation was deployed. After the Chernobyl cloud arrived in the UK on 2 May, there were numerous requests from local government, public authorities, private companies and members of the public for information and advice on monitoring equipment and procedures. Some of these requirements could be met with existing equipment but members of the public were usually advised not to proceed. At a later stage, the contamination of foodstuffs and livestock required the development of an instrument capable of detecting low levels of {sup 137}Cs and {sup 134}Cs in food

L-34: EPR-First Responders: Basic Radiation Instrumentation

International Nuclear Information System (INIS)

2011-01-01

This lecture is about radiation basic instrumentation, previous measurements, personnel dosimetry, Geiger Mueller, ionizing chambers, gamma spectrometry, contamination monitoring and radiation detection.

Method to Solve the Problem of the Radioactivity Detection in Environmental Samples. Characteristic Limits; Metodos para la Resolucion del Problema de la Detecfcion de Radiactividad en Muestras Ambientales. Limites Caracteristicos

Energy Technology Data Exchange (ETDEWEB)

Gasco, C.; Martinez, M.; Heras, M.

2009-07-21

The problem of the detection or when the radioactivity can be considered as higher than the background using different measurement techniques has been the objective of several statistical studies and controversies. The detection limit and the critical limit were studied by Currie in year 1968 and used by radiochemistry laboratories considering different ways of calculation that introduced confusion and not correct implementations. In the last few years, and due to the increasing number of standardization processes on the field of radioactivity and accreditation, several international institutions have chosen to unify the criteria for using common determination of detection limits. The most used methods are those developed by MARLAP and International Standard Organization ISO (Standard-11929). In this report are summarised both standards doing a comparative study and giving some examples of how to apply these limits. In same cases, little differences in the uncertainty calculation have been observed but the final results have been concordant. A deeply study of these standards can be done consulting the web page of the American Labs that developed MARLAP or buying the original ISO standard ISO-11929 recently approved (2009). (Author) 17 refs.

Tesla-VUPJT instruments suitable for application in water management

International Nuclear Information System (INIS)

Novakova, O.; Broj, K.; Fronka, O.; Kula, J.; Slezak, V.

1987-01-01

A comparison is made of new instruments by Tesla, Czechoslovakia, viz. the NA 6201 for low alpha and beta counting and the NRR 610 alpha-beta automatic gauge, with similar foreign made instruments. The factors are discussed which affect the overall detection efficiency and the background level. (B.S.). 4 tabs

Detecting terrestrial nutrient limitation: a global meta-analysis of foliar nutrient concentrations after fertilization

Directory of Open Access Journals (Sweden)

Rebecca eOstertag

2016-03-01

Full Text Available Examining foliar nutrient concentrations after fertilization provides an alternative method for detecting nutrient limitation of ecosystems, which is logistically simpler to measure than biomass change. We present a meta-analysis of response ratios of foliar nitrogen and phosphorus (RRN, RRP after addition of fertilizer of nitrogen (N, phosphorus (P, or the two elements in combination, in relation to climate, ecosystem type, life form, family, and methodological factors. Results support other meta-analyses using biomass, and demonstrate there is strong evidence for nutrient limitation in natural communities. However, because N fertilization experiments greatly outnumber P fertilization trials, it is difficult to discern the absolute importance of N vs. P vs. co-limitation across ecosystems. Despite these caveats, it is striking that results did not follow conventional wisdom that temperate ecosystems are N-limited and tropical ones are P-limited. In addition, the use of ratios of N-to-P rather than response ratios also are a useful index of nutrient limitation, but due to large overlap in values, there are unlikely to be universal cutoff values for delimiting N vs. P limitation. Differences in RRN and RRP were most significant across ecosystem types, plant families, life forms, and between competitive environments, but not across climatic variables.

The XRF spectrometer and the selection of analysis conditions (instrumental variables)

International Nuclear Information System (INIS)

Willis, J.P.

2002-01-01

Full text: This presentation will begin with a brief discussion of EDXRF and flat- and curved-crystal WDXRF spectrometers, contrasting the major differences between the three types. The remainder of the presentation will contain a detailed overview of the choice and settings of the many instrumental variables contained in a modern WDXRF spectrometer, and will discuss critically the choices facing the analyst in setting up a WDXRF spectrometer for different elements and applications. In particular it will discuss the choice of tube target (when a choice is possible), the kV and mA settings, tube filters, collimator masks, collimators, analyzing crystals, secondary collimators, detectors, pulse height selection, X-ray path medium (air, nitrogen, vacuum or helium), counting times for peak and background positions and their effect on counting statistics and lower limit of detection (LLD). The use of Figure of Merit (FOM) calculations to objectively choose the best combination of instrumental variables also will be discussed. This presentation will be followed by a shorter session on a subsequent day entitled - A Selection of XRF Conditions - Practical Session, where participants will be given the opportunity to discuss in groups the selection of the best instrumental variables for three very diverse applications. Copyright (2002) Australian X-ray Analytical Association Inc

Development of the Electron Drift Instrument (EDI) for Cluster

Science.gov (United States)

Quinn, Jack; Christensen, John L. (Technical Monitor)

2001-01-01

The Electron Drift Instrument (EDI) is a new technique for measuring electric fields in space by detecting the effect on weak beams of test electrons. This U.S. portions of the technique, flight hardware, and flight software were developed for the Cluster mission under this contract. Dr. Goetz Paschmann of the Max Planck Institute in Garching, Germany, was the Principle Investigator for Cluster EDI. Hardware for Cluster was developed in the U.S. at the University of New Hampshire, Lockheed Palo Alto Research Laboratory, and University of California, San Diego. The Cluster satellites carrying the original EDI instruments were lost in the catastrophic launch failure of first flight of the Arianne-V rocket in 1996. Following that loss, NASA and ESA approved a rebuild of the Cluster mission, for which all four satellites were successfully launched in the Summer of 2000. Limited operations of EDI were also obtained on the Equator-S satellite, which was launched in December, 1997. A satellite failure caused a loss of the Equator-S mission after only 5 months, but these operations were extremely valuable in learning about the characteristics and operations of the complex EDI instrument. The Cluster mission, satellites, and instruments underwent an extensive on-orbit commissioning phase in the Fall of 2000, carrying over through January 2001. During this period all elements of the instruments were checked and careful measurements of inter-experiments interferences were made. EDI is currently working exceptionally well in orbit. Initial results verify that all aspects of the instrument are working as planned, and returning highly valuable scientific information. The first two papers describing EDI on-orbit results have been submitted for publication in April, 2001. The principles of the EDI technique, and its implementation on Cluster are described in two papers by Paschmann et al., attached as Appendices A and B. The EDI presentation at the formal Cluster Commissioning

Analysis of detection limit to time-resolved coherent anti-Stokes Raman scattering nanoscopy

International Nuclear Information System (INIS)

Liu Wei; Liu Shuang-Long; Chen Dan-Ni; Niu Han-Ben

2014-01-01

In the implementation of CARS nanoscopy, signal strength decreases with focal volume size decreasing. A crucial problem that remains to be solved is whether the reduced signal generated in the suppressed focal volume can be detected. Here reported is a theoretical analysis of detection limit (DL) to time-resolved CARS (T-CARS) nanoscopy based on our proposed additional probe-beam-induced phonon depletion (APIPD) method for the low concentration samples. In order to acquire a detailed shot-noise limited signal-to-noise (SNR) and the involved parameters to evaluate DL, the T-CARS process is described with full quantum theory to estimate the extreme power density levels of the pump and Stokes beams determined by saturation behavior of coherent phonons, which are both actually on the order of ∼ 10 9 W/cm 2 . When the pump and Stokes intensities reach such values and the total intensity of the excitation beams arrives at a maximum tolerable by most biological samples in a certain suppressed focal volume (40-nm suppressed focal scale in APIPD method), the DL correspondingly varies with exposure time, for example, DL values are 10 3 and 10 2 when exposure times are 20 ms and 200 ms respectively. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Pre-concentration technique for reduction in "Analytical instrument requirement and analysis"

Science.gov (United States)

Pal, Sangita; Singha, Mousumi; Meena, Sher Singh

2018-04-01

Availability of analytical instruments for a methodical detection of known and unknown effluents imposes a serious hindrance in qualification and quantification. Several analytical instruments such as Elemental analyzer, ICP-MS, ICP-AES, EDXRF, ion chromatography, Electro-analytical instruments which are not only expensive but also time consuming, required maintenance, damaged essential parts replacement which are of serious concern. Move over for field study and instant detection installation of these instruments are not convenient to each and every place. Therefore, technique such as pre-concentration of metal ions especially for lean stream elaborated and justified. Chelation/sequestration is the key of immobilization technique which is simple, user friendly, most effective, least expensive, time efficient; easy to carry (10g - 20g vial) to experimental field/site has been demonstrated.

New limits on the detection of a composition-dependent macroscopic force

International Nuclear Information System (INIS)

Boynton, P.; Aronson, S.

1990-01-01

We report here on a continuing experimental search for a macroscopic, composition dependent force coupling to ordinary matter. Within the phenomenological framework commonly employed -- a Yukawa representation of the interaction potential, and composition specified as some linear combination of baryon and lepton numbers -- the Index 3 experiment sets the most stringent upper limits yet on the interaction strength for coupling from B-2L to B-L, and for an interaction range from 200 m to 10 km. It is also the first null result to conflict with the marginal detection reported for the Index 1 experiment for all relevant values of the composition and range parameters

Molecular techniques for detection and identification of pathogens in food: advantages and limitations

OpenAIRE

Palomino-Camargo, Carolina; Instituto de Ciencia y Tecnología de Alimentos, Facultad de Ciencias, Universidad Central de Venezuela. Caracas, Venezuela. Magíster en Ciencia y Tecnología de los Alimentos licenciada en Biología; González-Muñoz, Yuniesky; Instituto de Ciencia y Tecnología de Alimentos, Facultad de Ciencias, Universidad Central de Venezuela. Caracas, Venezuela. Ministerio del Poder Popular para la Alimentación. Caracas, Venezuela. licenciado en Ciencias de los Alimentos.

2014-01-01

Foodborne diseases, caused by pathogenic microorganisms, are a major public health problem worldwide. Microbiological methods commonly used in the detection of these foodborne pathogens are laborious and time consuming. This situation, coupled with the demand for immediate results and with technological advances, has led to the development of a wide range of rapid methods in recent decades. On this basis, this review describes the advantages and limitations of the main molecular methods used ...

Instrumental neutron activation analysis of brewer's yeast

International Nuclear Information System (INIS)

Bergerioux, C.; Zikovsky, L.

1978-01-01

Instrumental neutron activation was used for the determination of 23 trace and minor elements in 4 different samples of brewer's yeast. Detection limits vary from 2 ppb to 100 ppm. The following average concentrations were found (ppm, dry weight): Al 597, Br 0.36, Cl 1473, Co 0.21, Cu 19, Fe 285, K 16400, Mg 1355, Mn 8.4, Na 2330, Rb 19, Sb 0.053, Se 1.2, V 2.2 and Zn 80. NBS standard 1569 was also analyzed and the following concentrations (in ppm) were measured: Al 2300, Br 0.65, Ce 0.23, Cl 460, Co 0.26, Cr 2.12, Cu 11, Fe 707, Gd 7.1, Hf 0.13, K 15500, Mg 1780, Mn 7, Na 510, Rb 16, Sb 0.075, Sc 0.18, Se 0.92, Th 3.7, Ti 38, U 0.49, V 4.1 and Zn 70. (author)

The high resolution optical instruments for the Pleiades HR Earth observation satellites

Science.gov (United States)

Gaudin-Delrieu, Catherine; Lamard, Jean-Luc; Cheroutre, Philippe; Bailly, Bruno; Dhuicq, Pierre; Puig, Olivier

2017-11-01

Coming after the SPOT satellites series, PLEIADESHR is a CNES optical high resolution satellite dedicated to Earth observation, part of a larger optical and radar multi-sensors system, ORFEO, which is developed in cooperation between France and Italy for dual Civilian and Defense use. The development of the two PLEIADES-HR cameras was entrusted by CNES to Thales Alenia Space. This new generation of instrument represents a breakthrough in comparison with the previous SPOT instruments owing to a significant step in on-ground resolution, which approaches the capabilities of aerial photography. The PLEIADES-HR instrument program benefits from Thales Alenia Space long and successful heritage in Earth observation from space. The proposed solution benefits from an extensive use of existing products, Cannes Space Optics Centre facilities, unique in Europe, dedicated to High Resolution instruments. The optical camera provides wide field panchromatic images supplemented by 4 multispectral channels with narrow spectral bands. The optical concept is based on a four mirrors Korsch telescope. Crucial improvements in detector technology, optical fabrication and electronics make it possible for the PLEIADES-HR instrument to achieve the image quality requirements while respecting the drastic limitations of mass and volume imposed by the satellite agility needs and small launchers compatibility. The two flight telescopes were integrated, aligned and tested. After the integration phase, the alignment, mainly based on interferometric measurements in vacuum chamber, was successfully achieved within high accuracy requirements. The wave front measurements show outstanding performances, confirmed, after the integration of the PFM Detection Unit, by MTF measurements on the Proto-Flight Model Instrument. Delivery of the proto flight model occurred mi-2008. The FM2 Instrument delivery is planned Q2-2009. The first optical satellite launch of the PLEIADES-HR constellation is foreseen

Graduate studies in instrumentation at the University of Provence

International Nuclear Information System (INIS)

Carette, M.; Reynard, C.; Claire, N.; Deschaintres, J. L.; Felts, B.; Lyoussi, A.; Andre, J.; Bertin, D.

2009-01-01

The University of Provence instrumentation department offers a high level of graduate and post graduate engineering programs. Its mission is to form technician experts and engineers with a deep knowledge in their discipline: metrology, instrumentation, tests, Research and Development, automatism and industrial process control. The specialty of master on test facilities instrumentation has been developed in collaboration with the French Atomic Energy Commission (CEA) since 2004. This curriculum offers now a specialization in nuclear detection and nuclear instrumentation. More than 80% of the graduates formed by block-release training of master find a job within 6 months

Evaluation of the limits of visual detection of image misregistration in a brain fluorine-18 fluorodeoxyglucose PET-MRI study

International Nuclear Information System (INIS)

Wong, J.C.H.; Studholme, C.; Hawkes, D.J.; Maisey, M.N.

1997-01-01

In routine clinical work, registration accuracy is assessed by visual inspection. However, the accuracy of visual assessment of registration has not been evaluated. This study establishes the limits of visual detection of misregistration in a registered brain fluorine-18 fluorodeoxyglucose positron emission tomography to magnetic resonance image volume. The ''best'' registered image volume was obtained by automatic registration using mutual information optimization. Translational movements by 1 mm, 2 mm, 3 mm and 4 mm, and rotational movements by 1 , 2 , 3 and 4 in the positive and negative directions in the x- (lateral), y- (anterior-posterior) and z- (axial) axes were introduced to this standard. These 48 images plus six ''best'' registered images were presented in random sequence to five observers for visual categorization of registration accuracy. No observer detected a definite misregistration in the ''best'' registered image. Evaluation for inter-observer variation using observer pairings showed a high percentage of agreement in assigned categories for both translational and rotational misregistrations. Assessment of the limits of detection of misregistration showed that a 2-mm translational misregistration was detectable by all observers in the x- and y-axes and 3-mm translational misregistration in the z-axis. With rotational misregistrations, rotation around the z-axis was detectable by all at 2 rotation whereas rotation around the y-axis was detected at 3-4 . Rotation around the x-axis was not symmetric with a positive rotation being identified at 2 whereas negative rotation was detected by all only at 4 . Therefore, visual analysis appears to be a sensitive and practical means to assess image misregistration accuracy. The awareness of the limits of visual detection of misregistration will lead to increase care when evaluating registration quality in both research and clinical settings. (orig.). With 6 figs., 3 tabs

Particle size distribution instrument. Topical report 13

Energy Technology Data Exchange (ETDEWEB)

Okhuysen, W.; Gassaway, J.D.

1995-04-01

The development of an instrument to measure the concentration of particles in gas is described in this report. An in situ instrument was designed and constructed which sizes individual particles and counts the number of occurrences for several size classes. Although this instrument was designed to detect the size distribution of slag and seed particles generated at an experimental coal-fired magnetohydrodynamic power facility, it can be used as a nonintrusive diagnostic tool for other hostile industrial processes involving the formation and growth of particulates. Two of the techniques developed are extensions of the widely used crossed beam velocimeter, providing simultaneous measurement of the size distribution and velocity of articles.

Limits to the Fraction of High-energy Photon Emitting Gamma-Ray Bursts

Science.gov (United States)

Akerlof, Carl W.; Zheng, WeiKang

2013-02-01

After almost four years of operation, the two instruments on board the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts (GRBs) with high-energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of all such events, at least at the present detection limits. In a recent paper, we found that GRBs with photons detected in the Large Area Telescope have a surprisingly broad distribution with respect to the observed event photon number. Extrapolation of our empirical fit to numbers of photons below our previous detection limit suggests that the overall rate of such low flux events could be estimated by standard image co-adding techniques. In this case, we have taken advantage of the excellent angular resolution of the Swift mission to provide accurate reference points for 79 GRB events which have eluded any previous correlations with high-energy photons. We find a small but significant signal in the co-added field. Guided by the extrapolated power-law fit previously obtained for the number distribution of GRBs with higher fluxes, the data suggest that only a small fraction of GRBs are sources of high-energy photons.

LIMITS TO THE FRACTION OF HIGH-ENERGY PHOTON EMITTING GAMMA-RAY BURSTS

International Nuclear Information System (INIS)

Akerlof, Carl W.; Zheng, WeiKang

2013-01-01

After almost four years of operation, the two instruments on board the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts (GRBs) with high-energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of all such events, at least at the present detection limits. In a recent paper, we found that GRBs with photons detected in the Large Area Telescope have a surprisingly broad distribution with respect to the observed event photon number. Extrapolation of our empirical fit to numbers of photons below our previous detection limit suggests that the overall rate of such low flux events could be estimated by standard image co-adding techniques. In this case, we have taken advantage of the excellent angular resolution of the Swift mission to provide accurate reference points for 79 GRB events which have eluded any previous correlations with high-energy photons. We find a small but significant signal in the co-added field. Guided by the extrapolated power-law fit previously obtained for the number distribution of GRBs with higher fluxes, the data suggest that only a small fraction of GRBs are sources of high-energy photons.

Acoustic detection in superconducting magnets for performance characterization and diagnostics

International Nuclear Information System (INIS)

Marchevsky, M; Wang, X; Sabbi, G; Prestemon, S

2013-01-01

Quench diagnostics in superconducting accelerator magnets is essential for understanding performance limitations and improving magnet design. Applicability of the conventional quench diagnostics methods such as voltage taps or quench antennas is limited for long magnets or complex winding geometries, and alternative approaches are desirable. Here, we discuss acoustic sensing technique for detecting mechanical vibrations in superconducting magnets. Using LARP high-field Nb3Sn quadrupole HQ01, we show how acoustic data is connected with voltage instabilities measured simultaneously in the magnet windings during provoked extractions and current ramps to quench. Instrumentation and data analysis techniques for acoustic sensing are reviewed. (author)

Acoustic detection in superconducting magnets for performance characterization and diagnostics

CERN Document Server

Marchevsky, M.; Sabbi, G.; Prestemon, S.

2013-01-01

Quench diagnostics in superconducting accelerator magnets is essential for understanding performance limitations and improving magnet design. Applicability of the conventional quench diagnostics methods such as voltage taps or quench antennas is limited for long magnets or complex winding geometries, and alternative approaches are desirable. Here, we discuss acoustic sensing technique for detecting mechanical vibrations in superconducting magnets. Using LARP high-field Nb$_{3}$Sn quadrupole HQ01 [1], we show how acoustic data is connected with voltage instabilities measured simultaneously in the magnet windings during provoked extractions and current ramps to quench. Instrumentation and data analysis techniques for acoustic sensing are reviewed.

Biomarker detection for disease diagnosis using cost-effective microfluidic platforms.

Science.gov (United States)

Sanjay, Sharma T; Fu, Guanglei; Dou, Maowei; Xu, Feng; Liu, Rutao; Qi, Hao; Li, XiuJun

2015-11-07

Early and timely detection of disease biomarkers can prevent the spread of infectious diseases, and drastically decrease the death rate of people suffering from different diseases such as cancer and infectious diseases. Because conventional diagnostic methods have limited application in low-resource settings due to the use of bulky and expensive instrumentation, simple and low-cost point-of-care diagnostic devices for timely and early biomarker diagnosis is the need of the hour, especially in rural areas and developing nations. The microfluidics technology possesses remarkable features for simple, low-cost, and rapid disease diagnosis. There have been significant advances in the development of microfluidic platforms for biomarker detection of diseases. This article reviews recent advances in biomarker detection using cost-effective microfluidic devices for disease diagnosis, with the emphasis on infectious disease and cancer diagnosis in low-resource settings. This review first introduces different microfluidic platforms (e.g. polymer and paper-based microfluidics) used for disease diagnosis, with a brief description of their common fabrication techniques. Then, it highlights various detection strategies for disease biomarker detection using microfluidic platforms, including colorimetric, fluorescence, chemiluminescence, electrochemiluminescence (ECL), and electrochemical detection. Finally, it discusses the current limitations of microfluidic devices for disease biomarker detection and future prospects.

Laboratory Spacecraft Data Processing and Instrument Autonomy: AOSAT as Testbed

Science.gov (United States)

Lightholder, Jack; Asphaug, Erik; Thangavelautham, Jekan

2015-11-01

Recent advances in small spacecraft allow for their use as orbiting microgravity laboratories (e.g. Asphaug and Thangavelautham LPSC 2014) that will produce substantial amounts of data. Power, bandwidth and processing constraints impose limitations on the number of operations which can be performed on this data as well as the data volume the spacecraft can downlink. We show that instrument autonomy and machine learning techniques can intelligently conduct data reduction and downlink queueing to meet data storage and downlink limitations. As small spacecraft laboratory capabilities increase, we must find techniques to increase instrument autonomy and spacecraft scientific decision making. The Asteroid Origins Satellite (AOSAT) CubeSat centrifuge will act as a testbed for further proving these techniques. Lightweight algorithms, such as connected components analysis, centroid tracking, K-means clustering, edge detection, convex hull analysis and intelligent cropping routines can be coupled with the tradition packet compression routines to reduce data transfer per image as well as provide a first order filtering of what data is most relevant to downlink. This intelligent queueing provides timelier downlink of scientifically relevant data while reducing the amount of irrelevant downlinked data. Resulting algorithms allow for scientists to throttle the amount of data downlinked based on initial experimental results. The data downlink pipeline, prioritized for scientific relevance based on incorporated scientific objectives, can continue from the spacecraft until the data is no longer fruitful. Coupled with data compression and cropping strategies at the data packet level, bandwidth reductions exceeding 40% can be achieved while still downlinking data deemed to be most relevant in a double blind study between scientist and algorithm. Applications of this technology allow for the incorporation of instrumentation which produces significant data volumes on small spacecraft

Analysis of uncertainties and detection limits for the double measurement method of {sup 90}Sr and {sup 89}Sr

Energy Technology Data Exchange (ETDEWEB)

Herranz, M., E-mail: m.herranz@ehu.es [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n 48013 Bilbao (Spain); Idoeta, R.; Legarda, F. [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n 48013 Bilbao (Spain)

2011-08-15

The determination process of the {sup 90}Sr and {sup 89}Sr contents in a sample, although it involves their radiochemical isolation, results always in a complex measurement process due to the interferences among their respective beta emissions and also among those of the daughter of {sup 90}Sr, {sup 90}Y, a beta emitter as well. In this paper, the process consisting in a double measurement method after the Sr radiochemical isolation is analyzed, developing the formulae to obtain activity concentrations, uncertainties and detection limits. A study of the trend of uncertainties and detection limits as function of the time in which the first measurement since the isolation is done, the delay between the two measurements and the activity concentration of each strontium isotope in the sample is carried out as well. Results show that with a very precise determination of the times involved in the whole process (isolation, measurement and duration of measurements) this method permits a reliable assessment of both strontium radioisotopes. The quicker the first measurement since the isolation is done and the longer the delay between measurements is chosen, the lower are the detection limits and the uncertainties of the activities obtained. - Highlights: > The double measurement method for {sup 90}Sr and {sup 89}Sr determination is analysed. > Uncertainties and detection limits are determined and their dependences studied. > Proposals for the optimization of the method are given.

Post-implementation review of inadequate core cooling instrumentation

International Nuclear Information System (INIS)

Anderson, J.L.; Anderson, R.L.; Hagen, E.W.; Morelock, T.C.; Huang, T.L.; Phillips, L.E.

1988-01-01

Studies of Three Mile Island (TMI) accident identified the need for additional instrumentation to detect inadequate core cooling (ICC) in nuclear power plants. Industry studies by plant owners and reactor vendors supported the conclusion that improvements were needed to help operators diagnose the approach to or existence of ICC and to provide more complete information for operator control of safety injection, flow to minimize the consequences of such an accident. In 1980, the US Nuclear Regulatory Commission (NRC) required further studies by the industry and described ICC instrumentation design requirements that included human factors and environmental considerations. On December 10, 1982, NRC issued to Babcock and Wilcox (BandW) licensees' orders for Modification of License and transmitted to all pressurized water reactor (PWR) licensees Generic Letter 82-28 to inform them of the revised NRC requirements. The instrumentation requirements for detection of ICC include upgraded subcooling margin monitors (SMMs), upgraded core exit thermocouples (CETs), and installation of a reactor coolant inventory tracking system (RCITS)

University Reactor Instrumentation Program

International Nuclear Information System (INIS)

Vernetson, W.G.

1992-11-01

Recognizing that the University Reactor Instrumentation Program was developed in response to widespread needs in the academic community for modernization and improvement of research and training reactors at institutions such as the University of Florida, the items proposed to be supported by this grant over its two year period have been selected as those most likely to reduce foreed outages, to meet regulatory concerns that had been expressed in recent years by Nuclear Regulatory Commission inspectors or to correct other facility problems and limitations. Department of Energy Grant Number DE-FG07-90ER129969 was provided to the University of Florida Training Reactor(UFTR) facility through the US Department of Energy's University Reactor Instrumentation Program. The original proposal submitted in February, 1990 requested support for UFTR facility instrumentation and equipment upgrades for seven items in the amount of $107,530 with $13,800 of this amount to be the subject of cost sharing by the University of Florida and $93,730 requested as support from the Department of Energy. A breakdown of the items requested and total cost for the proposed UFTR facility instrumentation and equipment improvements is presented

Non-process instrumentation surveillance and test reduction

International Nuclear Information System (INIS)

Ferrell, R.; LeDonne, V.; Donat, T.; Thomson, I.; Sarlitto, M.

1993-12-01

Analysis of operating experience, instrument failure modes, and degraded instrument performance has led to a reduction in Technical Specification surveillance and test requirements for nuclear power plant process instrumentation. These changes have resulted in lower plant operations and maintenance (O ampersand M) labor costs. This report explores the possibility of realizing similar savings by reducing requirements for non-process instrumentation. The project team reviewed generic Technical Specifications for the four major US nuclear steam supply system (NSSS) vendors (Westinghouse, General Electric, Combustion Engineering, and Babcock ampersand Wilcox) to identify nonprocess instrumentation for which surveillance/test requirements could be reduced. The team surveyed 10 utilities to identify specific non-process instrumentation at their plants for which requirements could be reduced. The team evaluated utility analytic approaches used to justify changes in surveillance/test requirements for process equipment to determine their applicability to non-process instrumentation. The report presents a prioritized list of non-process instrumentation systems suitable for surveillance/test requirements reduction. The top three systems in the list are vibration monitors, leak detection monitors, and chemistry monitors. In general, most non-process instrumentation governed by Technical Specification requirements are candidates for requirements reduction. If statistical requirements are somewhat relaxed, the analytic approaches previously used to reduce requirements for process instrumentation can be applied to non-process instrumentation. The report identifies as viable the technical approaches developed and successfully used by Southern California Edison, Arizona Public Service, and Boston Edison

Detection of oscillatory components in noise signals and its application to fast detection of sodium boiling in LMFBR's

International Nuclear Information System (INIS)

Ehrhardt, J.

1975-09-01

In general, the surveillance of technical plants is performed by observating the mean value of measured signals. In this method not all information included in these signals is used. On the other hand - for example in a reactor - disturbances are possible which generate small oscillatory components in the measured signals. In general, these oscillatory components do not influence the mean value of the signals and consequently do not activate the conventional control system; however they can be found by analysis of the signal's noise component. For the detection of these oscillatory signals the observation of the frequency spectra of the noise signals is particularly advantageous because they produce peaks at the oscillation frequencies. In this paper a new detection system for the fast detection of suddenly appearing peaks in the frequency spectra of noise signals is presented. The prototype of a compact detection unit was developed which continuously computes the power spectral density (PSD) of noise signals and simultaneously supervises the PSD for peaks in the relevant frequency range. The detection method is not affected by the frequency dependance of the PSD and is applicable to any noise signal. General criteria were developed to enable the determination of the optimal detection system and its sensitivity. The upper limits of false alarm rate and detection time were taken into account. The detection criteria are applicable to all noise signals with approximately normally distributed amplitudes. Theoretical results were confirmed in a number of experiments; special experimental and theoretical parameter studies were done for the optimal detection of sodium boiling in LMFBR's. Computations based on these results showed that local and integral sodium boiling can be detected in a wide core range of SNR 300 by observing fluctuations of the neutron flux. In this connection it is important to point out that no additional core instrumentation is necessary because the

Comparison of the Multiattribute Utility Instruments EQ-5D and SF-6D in a Europe-Wide Population-Based Cohort of Patients with Inflammatory Bowel Disease 10 Years after Diagnosis

Directory of Open Access Journals (Sweden)

Gert Huppertz-Hauss

2016-01-01

Full Text Available Background. The treatment of chronic inflammatory bowel disease (IBD is costly, and limited resources call for analyses of the cost effectiveness of therapeutic interventions. The present study evaluated the equivalency of the Short Form 6D (SF-6D and the Euro QoL (EQ-5D, two preference-based HRQoL instruments that are broadly used in cost-effectiveness analyses, in an unselected IBD patient population. Methods. IBD patients from seven European countries were invited to a follow-up visit ten years after their initial diagnosis. Clinical and demographic data were assessed, and the Short Form 36 (SF-36 was employed. Utility scores were obtained by calculating the SF-6D index values from the SF-36 data for comparison with the scores obtained with the EQ-5D questionnaire. Results. The SF-6D and EQ-5D provided good sensitivities for detecting disease activity-dependent utility differences. However, the single-measure intraclass correlation coefficient was 0.58, and the Bland-Altman plot indicated numerous values beyond the limits of agreement. Conclusions. There was poor agreement between the measures retrieved from the EQ-5D and the SF-6D utility instruments. Although both instruments may provide good sensitivity for the detection of disease activity-dependent utility differences, the instruments cannot be used interchangeably. Cost-utility analyses performed with only one utility instrument must be interpreted with caution.

EPRTM Reactor neutron instrumentation

International Nuclear Information System (INIS)

Pfeiffer, Maxime; SALA, Stephanie

2013-06-01

The core safety during operation is linked, in particular, to the respect of criteria related to the heat generated in fuel rods and to the heat exchange between the rods and the coolant. This local power information is linked to the power distribution in the core. In order to evaluate the core power distribution, the EPR TM reactor relies on several types of neutron detectors: - ionization chambers located outside the vessel and used for protection and monitoring - a fixed in-core instrumentation based on Cobalt Self Powered Neutron Detectors used for protection and monitoring - a mobile reference in-core instrumentation based on Vanadium aero-balls This document provides a description of this instrumentation and its use in core protection, limitation, monitoring and control functions. In particular, a description of the detectors and the principles of their signal generation is supplied as well as the description of the treatments related to these detectors in the EPR TM reactor I and C systems (including periodical calibration). (authors)

A portable luminescence dating instrument

DEFF Research Database (Denmark)

Kook, M.H.; Murray, A.S.; Lapp, Torben

2011-01-01

We describe a portable luminescence reader suitable for use in remote localities in the field. The instrument weighs about 8kg and is based around a 30mm bialkali photomultiplier detecting signals through a glass filter centered on 340nm. Stimulation is by 470nm blue LEDs (24W in total) operating...

arXiv Particle Physics Instrumentation

CERN Document Server

Wingerter-Seez, I.

This reports summarizes the three lectures on particle physics instrumentation given during the AEPSHEP school in November 2014 at Puri-India. The lectures were intended to give an overview of the interaction of particles with matter and basic particle detection principles in the context of large detector systems like the Large Hadron Collider.

Amorphous semiconductors for particle detection: Physical and technical limits and possibilities

International Nuclear Information System (INIS)

Equer, B.; Karar, A.

1989-01-01

Amorphous silicon is used, at an industrial level, in at least three different fields of application: photovoltaic cells, flat TV screens and line scanners for image processing. In the last two cases, thin film transistors (TFT) are produced with the same technology. Particle detection with amorphous silicon has been demonstrated, but present performances are limited to ionizing particles. In this paper, we discuss the physical basis of amorphous semiconductors and the possible future development that can be expected on the basis of the existing technology. It is concluded that substitution of amorphous for crystalline silicon brings no clear advantage, if possible at all. Positive assets are to be found in using specific properties of thin layers: large area structures like arrays of photodiodes with associated readout are in the state of the art; vertical structures alternating layers of differently doped materials and/or of different semiconductors can be produced by the same technique. The development of large area pixel detectors is technically feasible but requires a very large effort. A joint development effort with industries involved in X-ray detection and 2D photodetectors might be the most appropriate solution. (orig.)

Atmospheric Sounder Spectrometer for Infrared Spectral Technology (ASSIST) Instrument Handbook

Energy Technology Data Exchange (ETDEWEB)

Flynn, Connor J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Radiation Measurement (ARM) Program

2016-03-01

The Atmospheric Sounder Spectrometer for Infrared Spectral Technology (ASSIST) measures the absolute infrared (IR) spectral radiance (watts per square meter per steradian per wavenumber) of the sky directly above the instrument. More information about the instrument can be found through the manufacturer’s website. The spectral measurement range of the instrument is 3300 to 520 wavenumbers (cm^-1) or 3-19.2 microns for the normal-range instruments and 3300 to 400 cm^-1 or 3-25 microns, for the extended-range polar instruments. Spectral resolution is 1.0 cm^-1. Instrument field-of-view is 1.3 degrees. Calibrated sky radiance spectra are produced on cycle of about 141 seconds with a group of 6 radiance spectra zenith having dwell times of about 14 seconds each interspersed with 55 seconds of calibration and mirror motion. The ASSIST data is comparable to the Atmospheric Emitted Radiance Interferometer (AERI) data and can be used for 1) evaluating line-by-line radiative transport codes, 2) detecting/quantifying cloud effects on ground-based measurements of infrared spectral radiance (and hence is valuable for cloud property retrievals), and 3) calculating vertical atmospheric profiles of temperature and water vapor and the detection of trace gases.

Definition of the limit of quantification in the presence of instrumental and non-instrumental errors. Comparison among various definitions applied to the calibration of zinc by inductively coupled plasma-mass spectrometry

Science.gov (United States)

Badocco, Denis; Lavagnini, Irma; Mondin, Andrea; Favaro, Gabriella; Pastore, Paolo

2015-12-01

The limit of quantification (LOQ) in the presence of instrumental and non-instrumental errors was proposed. It was theoretically defined combining the two-component variance regression and LOQ schemas already present in the literature and applied to the calibration of zinc by the ICP-MS technique. At low concentration levels, the two-component variance LOQ definition should be always used above all when a clean room is not available. Three LOQ definitions were accounted for. One of them in the concentration and two in the signal domain. The LOQ computed in the concentration domain, proposed by Currie, was completed by adding the third order terms in the Taylor expansion because they are of the same order of magnitude of the second ones so that they cannot be neglected. In this context, the error propagation was simplified by eliminating the correlation contributions by using independent random variables. Among the signal domain definitions, a particular attention was devoted to the recently proposed approach based on at least one significant digit in the measurement. The relative LOQ values resulted very large in preventing the quantitative analysis. It was found that the Currie schemas in the signal and concentration domains gave similar LOQ values but the former formulation is to be preferred as more easily computable.

Review of monitoring instruments for transuranics in fuel fabrication and reprocessing plants. A progress report to the physical and technological programs, Division of Biomedical and Environmental Research, U.S. Energy Research and Development Administration

International Nuclear Information System (INIS)

Kordas, J.F.; Phelps, P.L.

1977-01-01

A comprehensive review of the monitoring instruments for transuranic elements released from nuclear fuel fabrication and reprocessing plants has been compiled. The extent of routine operational releases has been reviewed for the light water reactor (LWR) fuel cycle (including plutonium recycle), the breeder reactor fuel cycle, and the high-temperature gas cooled reactor (HTGR) fuel cycle. The stack monitoring instrumentation that is presently in use at the various fabrication and reprocessing plants around the country is examined. Sampling difficulties including the inlet-probe arrangement and the effectiveness of the entire sampling system are discussed, as are the measurement problems for alpha-emitting, long-lived, transuranic aerosols, 129 I, 106 Ru, and tritium oxide. The potential problems in the HTGR fuel cycle such as the measurement of releases of alpha-emitting aerosols and of gaseous releases of 220 Rn and 14 C are also considered. Monitoring requirements range from the detection of low-level, routine releases to high-level accidental releases. Both first and second kinds of detection errors are considered in a discussion of adequate detection limits. The presently deployed monitors are critically examined in this light and the drawbacks and limitations of each are noted. Prototype instrumentation is studied, including Argonne's mechanical separation technique, Battelle's mass separation by surface ionization method, and in particular, LLL's transuranic aerosol measurement system. The potentials, sensitivities, advantages, and limitations of each system are enumerated. The additional potential uses of the LLL system are also discussed

Assessment of activity limitations and participation restrictions with persons with chronic fatigue syndrome: a systematic review.

Science.gov (United States)

Vergauwen, Kuni; Huijnen, Ivan P J; Kos, Daphne; Van de Velde, Dominique; van Eupen, Inge; Meeus, Mira

2015-01-01

To summarize measurement instruments used to evaluate activity limitations and participation restrictions in patients with chronic fatigue syndrome (CFS) and review the psychometric properties of these instruments. General information of all included measurement instruments was extracted. The methodological quality was evaluated using the COSMIN checklist. Results of the measurement properties were rated based on the quality criteria of Terwee et al. Finally, overall quality was defined per psychometric property and measurement instrument by use of the quality criteria by Schellingerhout et al. A total of 68 articles were identified of which eight evaluated the psychometric properties of a measurement instrument assessing activity limitations and participation restrictions. One disease-specific and 37 generic measurement instruments were found. Limited evidence was found for the psychometric properties and clinical usability of these instruments. However, the CFS-activities and participation questionnaire (APQ) is a disease-specific instrument with moderate content and construct validity. The psychometric properties of the reviewed measurement instruments to evaluate activity limitations and participation restrictions are not sufficiently evaluated. Future research is needed to evaluate the psychometric properties of the measurement instruments, including the other properties of the CFS-APQ. If it is necessary to use a measurement instrument, the CFS-APQ is recommended. Chronic fatigue syndrome (CFS). Chronic fatigue syndrome causes activity limitations and participation restrictions in one or more areas of life. Standardized, reliable and valid measurement instruments are necessary to identify these limitations and restrictions. Currently, no measurement instrument is sufficiently evaluated with persons with CFS. If a measurement instrument is needed to identify activity limitations and participation restrictions with persons with CFS, it is recommended to use

Development of assessment instruments to measure critical thinking skills

Science.gov (United States)

Sumarni, W.; Supardi, K. I.; Widiarti, N.

2018-04-01

Assessment instruments that is commonly used in the school generally have not been orientated on critical thinking skills. The purpose of this research is to develop assessment instruments to measure critical thinking skills, to test validity, reliability, and practicality. This type of research is Research and Development. There are two stages on the preface step, which are field study and literacy study. On the development steps, there some parts, which are 1) instrument construction, 2) expert validity, 3) limited scale tryout and 4) narrow scale try-out. The developed assessment instrument are analysis essay and problem solving. Instruments were declared valid, reliable and practical.

Enhancement of laser-induced breakdown spectroscopy (LIBS) Detection limit using a low-pressure and short-pulse laser-induced plasma process.

Science.gov (United States)

Wang, Zhen Zhen; Deguchi, Yoshihiro; Kuwahara, Masakazu; Yan, Jun Jie; Liu, Ji Ping

2013-11-01

Laser-induced breakdown spectroscopy (LIBS) technology is an appealing technique compared with many other types of elemental analysis because of the fast response, high sensitivity, real-time, and noncontact features. One of the challenging targets of LIBS is the enhancement of the detection limit. In this study, the detection limit of gas-phase LIBS analysis has been improved by controlling the pressure and laser pulse width. In order to verify this method, low-pressure gas plasma was induced using nanosecond and picosecond lasers. The method was applied to the detection of Hg. The emission intensity ratio of the Hg atom to NO (IHg/INO) was analyzed to evaluate the LIBS detection limit because the NO emission (interference signal) was formed during the plasma generation and cooling process of N2 and O2 in the air. It was demonstrated that the enhancement of IHg/INO arose by decreasing the pressure to a few kilopascals, and the IHg/INO of the picosecond breakdown was always much higher than that of the nanosecond breakdown at low buffer gas pressure. Enhancement of IHg/INO increased more than 10 times at 700 Pa using picosecond laser with 35 ps pulse width. The detection limit was enhanced to 0.03 ppm (parts per million). We also saw that the spectra from the center and edge parts of plasma showed different features. Comparing the central spectra with the edge spectra, IHg/INO of the edge spectra was higher than that of the central spectra using the picosecond laser breakdown process.

Validation of an analytical method for determining halothane in urine as an instrument for evaluating occupational exposure

International Nuclear Information System (INIS)

Gonzalez Chamorro, Rita Maria; Jaime Novas, Arelis; Diaz Padron, Heliodora

2010-01-01

The occupational exposure to harmful substances may impose the apparition of determined significative changes in the normal physiology of the organism when the adequate security measures are not taken in time in a working place where the risk may be present. Among the chemical risks that may affect the workers' health are the inhalable anesthetic agents. With the objective to take the first steps for the introduction of an epidemiological surveillance system to this personnel, an analytical method for determining this anesthetic in urine was validated with the instrumental conditions created in our laboratory. To carry out this validation the following parameters were taken into account: specificity, lineament, precision, accuracy, detection limit and quantification limit, and the uncertainty of the method was calculated. In the validation procedure it was found that the technique is specific and precise, the detection limit was of 0,118 μg/L, and of the quantification limit of 0,354 μg/L. The global uncertainty was of 0,243, and the expanded of 0,486. The validated method, together with the posterior introduction of the biological exposure limits, will serve as an auxiliary means of diagnosis which will allow us a periodical control of the personnel exposure

CAMAC-controlled calibration system for nuclear reactor instruments

International Nuclear Information System (INIS)

McDowell, W.P.; Cornella, R.J.

1977-01-01

The hardware and the software which have been developed to implement a nuclear instrument calibration system for the Argonne National Laboratory ZPR-VI and ZPR-IX reactor complex are described. The system is implemented using an SEL-840 computer with its associated CAMAC crates and a hardware interface to generate input parameters and measure the required outputs on the instrument under test. Both linear and logarithmic instruments can be calibrated by the system and output parameters can be measured at various automatically selected values of ac line voltage. A complete report on each instrument is printed as a result of the calibration and out-of-tolerance readings are flagged. Operator interface is provided by a CAMAC-controlled Hazeltine terminal. The terminal display leads the operator through the complete calibration procedure. This computer-controlled system is a significant improvement over previously used methods of calibrating nuclear instruments since it reduces reactor downtime and allows rapid detection of long-term changes in instrument calibration

Integrated optical detection of autonomous capillary microfluidic immunoassays:a hand-held point-of-care prototype.

Science.gov (United States)

Novo, P; Chu, V; Conde, J P

2014-07-15

The miniaturization of biosensors using microfluidics has potential in enabling the development of point-of-care devices, with the added advantages of reduced time and cost of analysis with limits-of-detection comparable to those obtained through traditional laboratory techniques. Interfacing microfluidic devices with the external world can be difficult especially in aspects involving fluid handling and the need for simple sample insertion that avoids special equipment or trained personnel. In this work we present a point-of-care prototype system by integrating capillary microfluidics with a microfabricated photodiode array and electronic instrumentation into a hand-held unit. The capillary microfluidic device is capable of autonomous and sequential fluid flow, including control of the average fluid velocity at any given point of the analysis. To demonstrate the functionality of the prototype, a model chemiluminescence ELISA was performed. The performance of the integrated optical detection in the point-of-care prototype is equal to that obtained with traditional bench-top instrumentation. The photodiode signals were acquired, displayed and processed by a simple graphical user interface using a computer connected to the microcontroller through USB. The prototype performed integrated chemiluminescence ELISA detection in about 15 min with a limit-of-detection of ≈2 nM with an antibody-antigen affinity constant of ≈2×10(7) M(-1). Copyright © 2014 Elsevier B.V. All rights reserved.

Detections and Sensitive Upper Limits for Methane and Related Trace Gases on Mars during 2003-2014, and planned extensions in 2016

Science.gov (United States)

Mumma, Michael J.; Villanueva, Geronimo L.; Novak, Robert E.

2015-11-01

Five groups report methane detections on Mars; all results suggest local release and high temporal variability [1-7]. Our team searched for CH4 on many dates and seasons and detected it on several dates [1, 9, 10]. TLS (Curiosity rover) reported methane upper limits [6], and then detections [7] that were consistent in size with earlier reports and that also showed rapid modulation of CH4 abundance.[8] argued that absorption features assigned to Mars 12CH4 by [1] might instead be weak lines of terrestrial 13CH4. If not properly removed, terrestrial 13CH4 signatures would appear on the blue wing of terrestrial 12CH4 even when Mars is red-shifted - but they do not (Fig. S6 of [1]), demonstrating that terrestrial signatures were correctly removed. [9] demonstrated that including the dependence of δ13CH4 with altitude did not affect the residual features, nor did taking δ13CH4 as zero. Were δ13CH4 important, its omission would have overemphasized the depth of 13CH4 terrestrial absorption, introducing emission features in the residual spectra [1]. However, the residual features are seen in absorption, establishing their origin as non-terrestrial - [8] now agrees with this view.We later reported results for multiple organic gases (CH4, CH3OH, H2CO, C2H6, C2H2, C2H4), hydroperoxyl (HO2), three nitriles (N2O, NH3, HCN) and two chlorinated species (HCl, CH3Cl) [9]. Most of these species cannot be detected with current space assets, owing to instrumental limitations (e.g., spectral resolving power). However, the high resolution infrared spectrometers (NOMAD, ACS) on ExoMars 2016 (Trace Gas Orbiter) will begin measurements in late 2016. In solar occultation, TGO sensitivities will far exceed prior capabilities.We published detailed hemispheric maps of H2O and HDO on Mars, inferring the size of a lost early ocean [10]. In 2016, we plan to acquire 3-D spatial maps of HDO and H2O with ALMA, and improved maps of organics with iSHELL/NASA-IRTF.References: [1] Mumma et al. Sci09

Global dust sources detection using MODIS Deep Blue Collection 6 aerosol products

Science.gov (United States)

Pérez García-Pando, C.; Ginoux, P. A.

2015-12-01

Our understanding of the global dust cycle is limited by a dearth of information about dust sources, especially small-scale features which could account for a large fraction of global emissions. Remote sensing sensors are the most useful tool to locate dust sources. These sensors include microwaves, visible channels, and lidar. On the global scale, major dust source regions have been identified using polar orbiting satellite instruments. The MODIS Deep Blue algorithm has been particularly useful to detect small-scale sources such as floodplains, alluvial fans, rivers, and wadis , as well as to identify anthropogenic sources from agriculture. The recent release of Collection 6 MODIS aerosol products allows to extend dust source detection to the entire land surfaces, which is quite useful to identify mid to high latitude dust sources and detect not only dust from agriculture but fugitive dust from transport and industrial activities. This presentation will overview the advantages and drawbacks of using MODIS Deep Blue for dust detection, compare to other instruments (polar orbiting and geostationary). The results of Collection 6 with a new dust screening will be compared against AERONET. Applications to long range transport of anthropogenic dust will be presented.

Performance tests for instruments measuring radon activity concentration

International Nuclear Information System (INIS)

Beck, T.R.; Buchroeder, H.; Schmidt, V.

2009-01-01

Performance tests of electronic instruments measuring the activity concentration of 222 Rn have been carried out with respect to the standard IEC 61577-2. In total, 9 types of instrument operating with ionization chambers or electrostatic collection have been tested for the influence of different climatic and radiological factors on the measurement characteristics. It is concluded that all types of instrument, which are commercially available, are suitable for indoor radon measurements. Because of the dependence on climatic conditions, the outdoor use is partly limited.

Laser light scattering instrument advanced technology development

Science.gov (United States)

Wallace, J. F.

1993-01-01

The objective of this advanced technology development (ATD) project has been to provide sturdy, miniaturized laser light scattering (LLS) instrumentation for use in microgravity experiments. To do this, we assessed user requirements, explored the capabilities of existing and prospective laser light scattering hardware, and both coordinated and participated in the hardware and software advances needed for a flight hardware instrument. We have successfully breadboarded and evaluated an engineering version of a single-angle glove-box instrument which uses solid state detectors and lasers, along with fiber optics, for beam delivery and detection. Additionally, we have provided the specifications and written verification procedures necessary for procuring a miniature multi-angle LLS instrument which will be used by the flight hardware project which resulted from this work and from this project's interaction with the laser light scattering community.

MURCHISON WIDEFIELD ARRAY LIMITS ON RADIO EMISSION FROM ANTARES NEUTRINO EVENTS

International Nuclear Information System (INIS)

Croft, S.; Kaplan, D. L.; Tingay, S. J.; Murphy, T.; Rowlinson, A.; Bell, M. E.; Adrián-Martínez, S.; Ardid, M.; Ageron, M.; Aubert, J.-J.; Albert, A.; André, M.; Anton, G.; Avgitas, T.; Baret, B.

2016-01-01

We present a search, using the Murchison Widefield Array (MWA), for electromagnetic (EM) counterparts to two candidate high-energy neutrino events detected by the ANTARES neutrino telescope in 2013 November and 2014 March. These events were selected by ANTARES because they are consistent, within 0.°4, with the locations of galaxies within 20 Mpc of Earth. Using MWA archival data at frequencies between 118 and 182 MHz, taken ∼20 days prior to, at the same time as, and up to a year after the neutrino triggers, we look for transient or strongly variable radio sources that are consistent with the neutrino positions. No such counterparts are detected, and we set a 5σ upper limit for low-frequency radio emission of ∼10 37 erg s −1 for progenitors at 20 Mpc. If the neutrino sources are instead not in nearby galaxies, but originate in binary neutron star coalescences, our limits place the progenitors at z ≳ 0.2. While it is possible, due to the high background from atmospheric neutrinos, that neither event is astrophysical, the MWA observations are nevertheless among the first to follow up neutrino candidates in the radio, and illustrate the promise of wide-field instruments like MWA for detecting EM counterparts to such events

MURCHISON WIDEFIELD ARRAY LIMITS ON RADIO EMISSION FROM ANTARES NEUTRINO EVENTS

Energy Technology Data Exchange (ETDEWEB)

Croft, S. [University of California, Berkeley, Astronomy Department, 501 Campbell Hall #3411, Berkeley, CA 94720 (United States); Kaplan, D. L. [Department of Physics, University of Wisconsin-Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Tingay, S. J. [International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102 (Australia); Murphy, T.; Rowlinson, A. [ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Bell, M. E. [CSIRO Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia); Adrián-Martínez, S.; Ardid, M. [Institut d’Investigació per a la Gestió Integrada de les Zones Costaneres (IGIC)—Universitat Politècnica de València. C/ Paranimf 1, E-46730 Gandia (Spain); Ageron, M.; Aubert, J.-J. [Aix Marseille Université, CNRS/IN2P3, CPPM UMR 7346, F-13288, Marseille (France); Albert, A. [GRPHE—Université de Haute Alsace—Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit BP 50568-68008 Colmar (France); André, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposició, E-08800 Vilanova i la Geltrú, Barcelona (Spain); Anton, G. [Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, D-91058 Erlangen (Germany); Avgitas, T.; Baret, B. [APC, Université Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, F-75205 Paris (France); Collaboration: for the MWA Collaboration; for the ANTARES Collaboration; for the TAROT Collaboration; for the ROTSE Collaboration; and others

2016-04-01

We present a search, using the Murchison Widefield Array (MWA), for electromagnetic (EM) counterparts to two candidate high-energy neutrino events detected by the ANTARES neutrino telescope in 2013 November and 2014 March. These events were selected by ANTARES because they are consistent, within 0.°4, with the locations of galaxies within 20 Mpc of Earth. Using MWA archival data at frequencies between 118 and 182 MHz, taken ∼20 days prior to, at the same time as, and up to a year after the neutrino triggers, we look for transient or strongly variable radio sources that are consistent with the neutrino positions. No such counterparts are detected, and we set a 5σ upper limit for low-frequency radio emission of ∼10{sup 37} erg s{sup −1} for progenitors at 20 Mpc. If the neutrino sources are instead not in nearby galaxies, but originate in binary neutron star coalescences, our limits place the progenitors at z ≳ 0.2. While it is possible, due to the high background from atmospheric neutrinos, that neither event is astrophysical, the MWA observations are nevertheless among the first to follow up neutrino candidates in the radio, and illustrate the promise of wide-field instruments like MWA for detecting EM counterparts to such events.

Field-portable Capillary Electrophoresis Instrument with Conductivity Detection

International Nuclear Information System (INIS)

Zhang, H F; Liu, X W; Wang, W; Wang, X L; Tian, L

2006-01-01

In this paper a novel capillary electrophoresis chip (CEC) is presented with integrated platinum electrodes and simplified conductivity detector. CEC is fabricated by the method of mechanical modification with probe on organic glass. Capillary electrophoresis chip can rapidly completed ion separation by simulation of concentration distribution and zone-broadening. Detection circuit is simple which can detect pA order current. This system has those advantages such as small volume, low power consumption and linearity, and well suit for field analysis

A novel dNTP-limited PCR and HRM assay to detect Williams-Beuren syndrome.

Science.gov (United States)

Zhang, Lichen; Zhang, Xiaoqing; You, Guoling; Yu, Yongguo; Fu, Qihua

2018-06-01

Williams-Beuren syndrome (WBS) is caused by a microdeletion of chromosome arm 7q11.23. A rapid and inexpensive genotyping method to detect microdeletion on 7q11.23 needs to be developed for the diagnosis of WBS. This study describes the development of a new type of molecular diagnosis method to detect microdeletion on 7q11.23 based upon high-resolution melting (HRM). Four genes on 7q11.23 were selected as the target genes for the deletion genotyping. dNTP-limited duplex PCR was used to amplify the reference gene, CFTR, and one of the four genes respectively on 7q11.23. An HRM assay was performed on the PCR products, and the height ratio of the negative derivative peaks between the target gene and reference gene was employed to analyze the copy number variation of the target region. A new genotyping method for detecting 7q11.23 deletion was developed based upon dNTP-limited PCR and HRM, which cost only 96 min. Samples from 15 WBS patients and 12 healthy individuals were genotyped by this method in a blinded fashion, and the sensitivity and specificity was 100% (95% CI, 0.80-1, and 95% CI, 0.75-1, respectively) which was proved by CytoScan HD array. The HRM assay we developed is an rapid, inexpensive, and highly accurate method for genotyping 7q11.23 deletion. It is potentially useful in the clinical diagnosis of WBS. Copyright © 2018 Elsevier B.V. All rights reserved.

Accurately Localize and Recognize Instruments with Substation Inspection Robot in Complex Environments

Directory of Open Access Journals (Sweden)

Hui Song

2014-07-01

Full Text Available This paper designs and develops an automatic detection system in the substation environment where complex and multi-inspecting objects exist. The inspection robot is able to fix and identify the objects quickly using a visual servo control system. This paper focuses on the analysis of fast lockup and recognition method of the substation instruments based on an improved Adaboost algorithm. The robot adjusts its position to the best view point and best resolution for the instrument in real-time. The dial and pointer of the instruments are detected with an improved Hough algorithm, and the angle of the pointer is converted to the corresponding readings. The experimental results indicate that the inspection robot can fix and identify the substation instruments quickly, and has a wide range of practical applications.

Neutron activation analysis detection limits using 252Cf sources

International Nuclear Information System (INIS)

DiPrete, D.P.; Sigg, R.A.

2000-01-01

The Savannah River Technology Center (SRTC) developed a neutron activation analysis (NAA) facility several decades ago using low-flux 252 Cf neutron sources. Through this time, the facility has addressed areas of applied interest in managing the Savannah River Site (SRS). Some applications are unique because of the site's operating history and its chemical-processing facilities. Because sensitivity needs for many applications are not severe, they can be accomplished using an ∼6-mg 252 Cf NAA facility. The SRTC 252 Cf facility continues to support applied research programs at SRTC as well as other SRS programs for environmental and waste management customers. Samples analyzed by NAA include organic compounds, metal alloys, sediments, site process solutions, and many other materials. Numerous radiochemical analyses also rely on the facility for production of short-lived tracers, yielding by activation of carriers and small-scale isotope production for separation methods testing. These applications are more fully reviewed in Ref. 1. Although the flux [approximately2 x 10 7 n/cm 2 ·s] is low relative to reactor facilities, more than 40 elements can be detected at low and sub-part-per-million levels. Detection limits provided by the facility are adequate for many analytical projects. Other multielement analysis methods, particularly inductively coupled plasma atomic emission and inductively coupled plasma mass spectrometry, can now provide sensitivities on dissolved samples that are often better than those available by NAA using low-flux isotopic sources. Because NAA allows analysis of bulk samples, (a) it is a more cost-effective choice when its sensitivity is adequate than methods that require digestion and (b) it eliminates uncertainties that can be introduced by digestion processes

An efficient probe for rapid detection of cyanide in water at parts per billion levels and naked-eye detection of endogenous cyanide.

Science.gov (United States)

Kumari, Namita; Jha, Satadru; Bhattacharya, Santanu

2014-03-01

A new molecular probe based on an oxidized bis-indolyl skeleton has been developed for rapid and sensitive visual detection of cyanide ions in water and also for the detection of endogenously bound cyanide. The probe allows the "naked-eye" detection of cyanide ions in water with a visual color change from red to yellow (Δλmax =80 nm) with the immediate addition of the probe. It shows high selectivity towards the cyanide ion without any interference from other anions. The detection of cyanide by the probe is ratiometric, thus making the detection quantitative. A Michael-type addition reaction of the probe with the cyanide ion takes place during this chemodosimetric process. In water, the detection limit was found to be at the parts per million level, which improved drastically when a neutral micellar medium was employed, and it showed a parts-per-billion-level detection, which is even 25-fold lower than the permitted limits of cyanide in water. The probe could also efficiently detect the endogenously bound cyanide in cassava (a staple food) with a clear visual color change without requiring any sample pretreatment and/or any special reaction conditions such as pH or temperature. Thus the probe could serve as a practical naked-eye probe for "in-field" experiments without requiring any sophisticated instruments. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. I. INSTRUMENT DESCRIPTION AND FIRST RESULTS

International Nuclear Information System (INIS)

Horch, Elliott P.; Veillette, Daniel R.; Shah, Sagar C.; O'Rielly, Grant V.; Baena Galle, Roberto; Van Altena, William F.

2009-01-01

First results of a new speckle imaging system, the Differential Speckle Survey Instrument, are reported. The instrument is designed to take speckle data in two filters simultaneously with two independent CCD imagers. This feature results in three advantages over other speckle cameras: (1) twice as many frames can be obtained in the same observation time which can increase the signal-to-noise ratio for astrometric measurements, (2) component colors can be derived from a single observation, and (3) the two colors give substantial leverage over atmospheric dispersion, allowing for subdiffraction-limited separations to be measured reliably. Fifty-four observations are reported from the first use of the instrument at the Wisconsin-Indiana-Yale-NOAO 3.5 m Telescope 9 The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories. in 2008 September, including seven components resolved for the first time. These observations are used to judge the basic capabilities of the instrument.

In situ detection of atomic and molecular iodine using Resonance and Off-Resonance Fluorescence by Lamp Excitation: ROFLEX

Directory of Open Access Journals (Sweden)

J. C. Gómez Martín

2011-01-01

Full Text Available We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I₂ fluorescence is achieved via quantitative detection of the molecule by Incoherent Broad Band Cavity-enhanced Absorption Spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I₂ concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 13 pptv for I₂, for S/N = 1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.

Re-evaluation of groundwater monitoring data for glyphosate and bentazone by taking detection limits into account

DEFF Research Database (Denmark)

Hansen, Claus Toni; Ritz, Christian; Gerhard, Daniel

2015-01-01

.e. samples with concentrations below the detection limit, as left-censored observations. The median calculated pesticide concentrations are shown to be reduced 10(4) to 10(5) fold for two representative herbicides (glyphosate and bentazone) relative to the median concentrations based upon observations above...

The Advanced Limiter Test-I (ALT-I) variable-geometry pump limiter module

International Nuclear Information System (INIS)

Pontau, A.E.; Malinowski, M.E.; Ver Berkmoes, A.A.; Guthrie, S.E.; Watson, R.D.; Goebel, D.M.; Campbell, G.A.

1984-01-01

The ALT-I variable geometry module has been designed to address many of the issues not previously settled by earlier experiments. The goal is to study the basic processes involved in pump limiter operation as well as demonstrate its utility and effect on the plasma. The flexibility and extensive instrumentation of ALT-I will offer a unique opportunity to parameterize operation and facilitate the engineering design of future pump limiters. (orig.)

Hilbert-Huang transform based instrumental assessment of intention tremor in multiple sclerosis

Science.gov (United States)

Carpinella, Ilaria; Cattaneo, Davide; Ferrarin, Maurizio

2015-08-01

Objective. This paper describes a method to extract upper limb intention tremor from gyroscope data, through the Hilbert-Huang transform (HHT), a technique suitable for the study of nonlinear and non-stationary processes. The aims of the study were to: (i) evaluate the method’s ability to discriminate between healthy controls and MS subjects; (ii) validate the proposed procedure against clinical tremor scores assigned using Fahn’s tremor rating scale (FTRS); and (iii) compare the performance of the HHT-based method with that of linear band-pass filters. Approach. HHT was applied on gyroscope data collected on 20 MS subjects and 13 healthy controls (CO) during finger-to-nose tests (FNTs) instrumented with an inertial sensor placed on the hand. The results were compared to those obtained after traditional linear filtering. The tremor amplitude was quantified with instrumental indexes (TIs) and clinical FTRS ratings. Main results. The TIs computed after HHT-based filtering discriminated between CO and MS subjects with clinically-detected intention tremor (MS_T). In particular, TIs were significantly higher in the final part of the movement (TI2) with respect to the first part (TI1), and, for all components (X, Y, Z), MST showed a TI2 significantly higher than in CO subjects. Moreover, the HHT detected subtle alterations not visible from clinical ratings, as TI2 (Z-component) was significantly increased in MS subjects without clinically-detected tremor (MS_NT). The method’s validity was demonstrated by significant correlations between clinical FTRS scores and TI2 related to X (rs = 0.587, p = 0.006) and Y (rs = 0.682, p < 0.001) components. Contrarily, fewer differences among the groups and no correlation between instrumental and clinical indexes emerged after traditional filtering. Significance. The present results supported the use of the HHT-based procedure for a fully-automated quantitative and objective measure of intention tremor in MS, which can overcome

On the definition of the detection limit for non-selective determination of low activities

International Nuclear Information System (INIS)

Tschurlovits, M.

1977-01-01

Based on the latest published results, a detection limit which is easy to use in practical work without intensive consideration of counting statistics, is presented. The primary application of the given definition is the determination of gross activity. In the definition the error of the second kind as well as one-sided boundedness of the normal distribution are included. The results are given in graphical form. (orig.) [de

Automatic localization of the da Vinci surgical instrument tips in 3-D transrectal ultrasound.

Science.gov (United States)

Mohareri, Omid; Ramezani, Mahdi; Adebar, Troy K; Abolmaesumi, Purang; Salcudean, Septimiu E

2013-09-01

Robot-assisted laparoscopic radical prostatectomy (RALRP) using the da Vinci surgical system is the current state-of-the-art treatment option for clinically confined prostate cancer. Given the limited field of view of the surgical site in RALRP, several groups have proposed the integration of transrectal ultrasound (TRUS) imaging in the surgical workflow to assist with accurate resection of the prostate and the sparing of the neurovascular bundles (NVBs). We previously introduced a robotic TRUS manipulator and a method for automatically tracking da Vinci surgical instruments with the TRUS imaging plane, in order to facilitate the integration of intraoperative TRUS in RALRP. Rapid and automatic registration of the kinematic frames of the da Vinci surgical system and the robotic TRUS probe manipulator is a critical component of the instrument tracking system. In this paper, we propose a fully automatic registration technique based on automatic 3-D TRUS localization of robot instrument tips pressed against the air-tissue boundary anterior to the prostate. The detection approach uses a multiscale filtering technique to identify and localize surgical instrument tips in the TRUS volume, and could also be used to detect other surface fiducials in 3-D ultrasound. Experiments have been performed using a tissue phantom and two ex vivo tissue samples to show the feasibility of the proposed methods. Also, an initial in vivo evaluation of the system has been carried out on a live anaesthetized dog with a da Vinci Si surgical system and a target registration error (defined as the root mean square distance of corresponding points after registration) of 2.68 mm has been achieved. Results show this method's accuracy and consistency for automatic registration of TRUS images to the da Vinci surgical system.

Internal Dosimetry Monitoring- Detection Limits for a Selected Set of Radionuclides and Their Translation Into Committed Effective Dose

International Nuclear Information System (INIS)

Brandl, A.; Hrnecek, E.; Steger, F.

2004-01-01

To harmonize the practice of internal dosimetry monitoring across the country, the Austrian Standards Institute is currently drafting a new set of standards which are concerned with occupational incorporation monitoring of individuals handling non-sealed radioactive material. This set of standards is expected to consist of three parts discussing the general necessity and frequency, the requirements for monitoring institutions, and the determination and rigorous calculation of committed effective dose after incorporation of radioactive material, respectively. Considerations of the requirements for routine monitoring laboratories have led to an evaluation of the detection limits for routine monitoring equipment. For a selected set of radionuclides, these detection limits are investigated in detail. The main emphasis is placed on the decay chains of naturally occurring radionuclides showing some significant potential for being out of equilibrium due to chemical processes in certain mining industries. The radionuclides considered in this paper are 226Ra, 228Ra, 228Th, 232Th, 234U, 235U, and 238U. Given the routine monitoring intervals of the Austrian Standard, these detection limits are translated into information on committed effective dose. This paper investigates whether routine monitoring equipment is sufficient to ensure compliance with EC directive 96/29/Euratom for this selected set of radionuclides. (Author) 9 refs

The Evaluation of a Low-Cost Colorimeter for Glucose Detection in Salivary Samples.