WorldWideScience

Sample records for absorption detection technique

  1. Element selective detection of molecular species applying chromatographic techniques and diode laser atomic absorption spectrometry.

    Science.gov (United States)

    Kunze, K; Zybin, A; Koch, J; Franzke, J; Miclea, M; Niemax, K

    2004-12-01

    Tunable diode laser atomic absorption spectroscopy (DLAAS) combined with separation techniques and atomization in plasmas and flames is presented as a powerful method for analysis of molecular species. The analytical figures of merit of the technique are demonstrated by the measurement of Cr(VI) and Mn compounds, as well as molecular species including halogen atoms, hydrogen, carbon and sulfur.

  2. Mercury speciation in environmental solid samples using thermal release technique with atomic absorption detection

    Energy Technology Data Exchange (ETDEWEB)

    Shuvaeva, Olga V. [Institute of Inorganic Chemistry, Academician Lavrent' ev Prospect 3, 630090 Novosbirsk (Russian Federation)], E-mail: olga@che.nsk.su; Gustaytis, Maria A.; Anoshin, Gennadii N. [Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Koptyug Prospect 3, 630090 Novosibirsk (Russian Federation)

    2008-07-28

    A sensitive and very simple method for determination of mercury species in solid samples has been developed involving thermal release analysis in combination with atomic absorption (AAS) detection. The method allows determination of mercury(II) chloride, methylmercury and mercury sulfide at the level of 0.70, 0.35 and 0.20 ng with a reproducibility of the results of 14, 25 and 18%, respectively. The accuracy of the developed assay has been estimated using certified reference materials and by comparison of the results with those of an independent method. The method has been applied for Hg species determination in original samples of lake sediments and plankton.

  3. Gamm-ray absorption techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    In this chapter the principles of gamma-ray absorption are described and important applications in plant and process techniques such as measurement of thickness of deposits on pipes, checking for voids in concrete, metal corrosion, measurement of the density of materials inside vessels in industrial radiography are discussed. (U.K.)

  4. Ultraviolet absorption detection of DNA in gels

    International Nuclear Information System (INIS)

    Mahon, A.R.

    1998-01-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled deoxyribonucleic acid (DNA) in agarose gels is presented. The technique is based on ultra-violet (UV) absorption by nucleotides. A deuterium lamp was used to illuminate regions of an electrophoresis gel. As DNA bands passed through the illuminated region of the gel the amount of UV light transmitted was reduced due to DNA absorption. Two detection systems were investigated. In the first system, synthetic chemical vapour deposition (CVD) diamond strip detectors were used to locate regions of DNA in the gels by detecting the transmitted light. CVD diamond has a high indirect band gap of 5.45 eV and is therefore sensitive to UV photons of wavelengths < 224 nm. A number of CVD diamond samples were characterised to investigate their suitability as detectors for this application. The detectors' quantum efficiency, UV response and time response were measured. DNA bands containing as little as 20 ng were detected by the diamond. In a second system, a deuterium lamp was used to illuminate individual sample lanes of an electrophoresis gel via an array of optical fibres. During electrophoresis the regions of DNA were detected with illumination at 260 nm, using a UV-sensitive charge coupled device (CCD). As the absorption coefficient of a DNA sample is approximately proportional to its mass, the technique is inherently quantitative. This system had a detection limit of 0.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. Using this detection technique, the DNA sample remains in its native state. The removal of carcinogenic dyes from the detection procedure greatly reduces associated biological hazards. (author)

  5. Gold analysis by the gamma absorption technique

    International Nuclear Information System (INIS)

    Kurtoglu, Arzu; Tugrul, A.B.

    2003-01-01

    Gold (Au) analyses are generally performed using destructive techniques. In this study, the Gamma Absorption Technique has been employed for gold analysis. A series of different gold alloys of known gold content were analysed and a calibration curve was obtained. This curve was then used for the analysis of unknown samples. Gold analyses can be made non-destructively, easily and quickly by the gamma absorption technique. The mass attenuation coefficients of the alloys were measured around the K-shell absorption edge of Au. Theoretical mass attenuation coefficient values were obtained using the WinXCom program and comparison of the experimental results with the theoretical values showed generally good and acceptable agreement

  6. High sensitivity probe absorption technique for time-of-flight ...

    Indian Academy of Sciences (India)

    Abstract. We report on a phase-sensitive probe absorption technique with high sen- sitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms.

  7. Pipeline Leak Detection Techniques

    OpenAIRE

    Chis, Timur

    2009-01-01

    Leak detection systems range from simple, visual line walking and checking ones to complex arrangements of hard-ware and software. No one method is universally applicable and operating requirements dictate which method is the most cost effective. The aim of the paper is to review the basic techniques of leak detection that are currently in use. The advantages and disadvantages of each method are discussed and some indications of applicability are outlined.

  8. Pipeline Leak Detection Techniques

    Directory of Open Access Journals (Sweden)

    Timur Chis, Ph.D., Dipl.Eng.

    2007-01-01

    Full Text Available Leak detection systems range from simple, visual line walking and checking ones to complex arrangements of hard-ware and software. No one method is universally applicable and operating requirements dictate which method is the most cost effective. The aim of the paper is to review the basic techniques of leak detection that are currently in use. The advantages and disadvantages of each method are discussed and some indications of applicability are outlined.

  9. Techniques For Measuring Absorption Coefficients In Crystalline Materials

    Science.gov (United States)

    Klein, Philipp H.

    1981-10-01

    Absorption coefficients smaller than 0.001 cm-1 can, with more or less difficulty, be measured by several techniques. With diligence, all methods can be refined to permit measurement of absorption coefficients as small as 0.00001 cm-1. Spectral data are most readily obtained by transmission (spectrophotometric) methods, using multiple internal reflection to increase effective sample length. Emissivity measurements, requiring extreme care in the elimination of detector noise and stray light, nevertheless afford the most accessible spectral data in the 0.0001 to 0.00001 cm-1 range. Single-wavelength informa-tion is most readily obtained with modifications of laser calorimetry. Thermo-couple detection of energy absorbed from a laser beam is convenient, but involves dc amplification techniques and is susceptible to stray-light problems. Photoacoustic detection, using ac methods, tends to diminish errors of these types, but at some expense in experimental complexity. Laser calorimetry has been used for measurements of absorption coefficients as small as 0.000003 cm-1. Both transmission and calorimetric data, taken as functions of intensity, have been used for measurement of nonlinear absorption coefficients.

  10. Neutron detection technique

    International Nuclear Information System (INIS)

    Oblath, N.S.; Poon, A.W.P.

    2000-01-01

    The Sudbury Neutrino Observatory (SNO) has the ability to measure the total flux of all active flavors of neutrinos using the neutral current reaction, whose signature is a neutron. By comparing the rates of the neutral current reaction to the charged current reaction, which only detects electron neutrinos, one can test the neutrino oscillation hypothesis independent of solar models. It is necessary to understand the neutron detection efficiency of the detector to make use of the neutral current reaction. This report demonstrates a coincidence technique to identify neutrons emitted from the 252 Cf neutron calibration source. The source releases on average four neutrons when a 252 Cf nucleus spontaneously fissions. Each neutron is detected as a separate event when the neutron is captured by a deuteron, releasing a gamma ray of approximately 6.25 MeV. This gamma ray is in turn detected by the photomultiplier tube (PMT) array. By investigating the time and spatial separation between neutron-like events, it is possible to obtain a pure sample of neutrons for calibration study. Preliminary results of the technique applied to two calibration runs are presented

  11. Focused detection logging technique

    International Nuclear Information System (INIS)

    Turcotte, R.E.

    1977-01-01

    In accordance with an illustrative embodiment of the present invention, a method and apparatus is disclosed for determining a characteristic of the media surrounding a borehole by emitting gamma radiation in at least one tightly collimated beam toward an earth formation adjacent a borehole, by detecting from a plurality of tightly collimated paths that are focused at a zone of intersection with and aligned to intersect with each emitted beam the gamma radiation scattered by the interaction of the emitted gamma radiation and the media at the zones of intersection, by misaligning the emitted beams and the tightly collimated paths to prevent their intersection, by detecting gamma radiation scattered by the interaction of the emitted gamma radiation and the media with the emitted beams and the tightly collimated paths misaligned and by determining from the detected gamma radiation a media characteristic. In one embodiment, the detection collimater used is formed of a material that is essentially opaque to gamma radiation at the energies of interest and includes a plurality of passageways that are spherically focused at a zone of intersection with one of the emitted beams of gamma radiation and that are arranged in a number of surfaces that are curved to be azimuthally symmetrical about the axis of the intersected beam. 14 figures

  12. Cell Phone Detection Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Richard M.; Bunch, Kyle J.; Puzycki, David J.; Slaugh, Ryan W.; Good, Morris S.; McMakin, Douglas L.

    2007-10-01

    A team composed of Rick Pratt, Dave Puczyki, Kyle Bunch, Ryan Slaugh, Morris Good, and Doug McMakin teamed together to attempt to exploit cellular telephone features and detect if a person was carrying a cellular telephone into a Limited Area. The cell phone’s electromagnetic properties were measured, analyzed, and tested in over 10 different ways to determine if an exploitable signature exists. The method that appears to have the most potential for success without adding an external tag is to measure the RF spectrum, not in the cell phone band, but between 240 and 400MHz. Figures 1- 7 show the detected signal levels from cell phones from three different manufacturers.

  13. Detection of corrosion by a radiometric technique

    International Nuclear Information System (INIS)

    Charlton, J.S.; Ross, J.F.

    1975-01-01

    A method is described for the detection and measurement of corrosion in metal tube bundles using a radioisotope technique. The method is stated to be accurate and quick, and dismantling is unnecessary. A radioactive source is inserted into one of the tubes of the bundle and radiation detectors are inserted into the remainder of the tubes, which may be up to six in number with the apparatus described. The radiation absorption by the walls of each pair of tubes is compared with a standard measurement representing a known thickness of the material of the tubes. Simultaneous measurements may be made. Suitable apparatus is described in detail. (U.K.)

  14. Carbon filter property detection with thermal neutron technique

    International Nuclear Information System (INIS)

    Deng Zhongbo; Han Jun; Li Wenjie

    2003-01-01

    The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

  15. Analysis of photoisomerizable dyes using laser absorption and fluorescence techniques

    International Nuclear Information System (INIS)

    Duchowicz, R.; Di Paolo, R.E.; Scaffardi, L.; Tocho, J.O.

    1992-01-01

    The attention of the present report has been directed mainly to the description of laser-based techniques developed in order to obtain kinetic and spectroscopic properties of polymethine cyanine dyes in solution. Special attention was dedicated to photoisomerizable molecules where the absorption spectra of both isomers are strongly overlapped. As an example, measurements of two different dyes of laser technological interest, DTCI and DODCI were performed. The developed methods provide a complete quantitative description of photophysical processes. (author). 14 refs, 6 figs

  16. Double wavelength differential absorption as a technique for early diagnosis of breast cancer

    Science.gov (United States)

    Liger, Vladimir V.; Zybin, Alexander V.; Niemax, Kay; Kuritsyn, Yuri A.; Bolshov, Mikhail A.

    2005-08-01

    The double-wavelength differential molecular absorption technique with diode lasers is proposed for sensitive detection of functional status of breast tissues. The method is based on the measurement of the transmitted intensity differences of the two beams of diode lasers tuned to selected wavelengths within a broad absorption band of a human breast tissue within 700 - 800 nm spectral range. The strategy for the optimum selection of the diode laser wavelengths and initial adjustment of the detection scheme is developed. The method is demonstrated by the detection of the relative concentrations of two dyes, the optical properties of which are similar to those of a mixture of oxy- and deoxy- hemoglobin. The results of the first clinical tests of the proposed technique are briefly described.

  17. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    International Nuclear Information System (INIS)

    Morgado, R.E.; Arnone, G.J.; Cappiello, C.C.

    1996-01-01

    A laboratory prototype system has been developed for the experimental evaluation of an explosives detection technique based on nuclear resonance absorption of gamma rays in nitrogen. Major subsystems include a radiofrequency quadrupole proton accelerator and associated beam transport system, a high-power gamma-ray production target, an airline-luggage tomographic inspection system, and an image- processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported

  18. New analytical technique for carbon dioxide absorption solvents

    Energy Technology Data Exchange (ETDEWEB)

    Pouryousefi, F.; Idem, R.O. [University of Regina, Regina, SK (Canada). Faculty of Engineering

    2008-02-15

    The densities and refractive indices of two binary systems (water + MEA and water + MDEA) and three ternary systems (water + MEA + CO{sub 2}, water + MDEA + CO{sub 2}, and water + MEA + MDEA) used for carbon dioxide (CO{sub 2}) capture were measured over the range of compositions of the aqueous alkanolamine(s) used for CO{sub 2} absorption at temperatures from 295 to 338 K. Experimental densities were modeled empirically, while the experimental refractive indices were modeled using well-established models from the known values of their pure-component densities and refractive indices. The density and Gladstone-Dale refractive index models were then used to obtain the compositions of unknown samples of the binary and ternary systems by simultaneous solution of the density and refractive index equations. The results from this technique have been compared with HPLC (high-performance liquid chromatography) results, while a third independent technique (acid-base titration) was used to verify the results. The results show that the systems' compositions obtained from the simple and easy-to-use refractive index/density technique were very comparable to the expensive and laborious HPLC/titration techniques, suggesting that the refractive index/density technique can be used to replace existing methods for analysis of fresh or nondegraded, CO{sub 2}-loaded, single and mixed alkanolamine solutions.

  19. Detection of atomic oxygen in flames by absorption spectroscopy

    International Nuclear Information System (INIS)

    Cheskis, S.; Kovalenko, S.A.

    1994-01-01

    The absolute concentration of atomic oxygen in an atmospheric pressure hydrogen/air flame has been measured using Intracavity Laser Spectroscopy (ICLS) based on a dye laser pumped by an argon-ion laser. Absorptions at the highly forbidden transitions at 630.030 nm and 636.380 nm were observed at an equivalent optical length of up to 10 km. The relatively low intensity of the dye laser avoids photochemical interferences that are inherent to some other methods for detecting atomic oxygen. The detection sensitivity is about 6x10 14 atom/cm 3 and can be improved with better flame and laser stabilization. (orig.)

  20. Absorption of human skin and its detecting platform in the process of laser cosmetology

    Science.gov (United States)

    Zhang, Yong-Lin; Ouyang, Li; Wang, Yang

    2000-10-01

    Because of the melanin, hemoglobin and water molecules, etc. contained, light absorption of human skin tissue changes with wavelength of light. This is the principle used in laser cosmetology for treating pigment diseases and vascular lesion diseases as well as skin decoration such as body tattooing, eyebrow tattooing, etc. The parameters of treatment used in laser cosmetology principally come from the research of the skin tissue optical characteristics of whites, and it is not suitable for the Oriental. The absorption spectrum of yellow race alive skin has been researched. The detecting platform for use in the measuring of vivi-tissue absorption spectrum has been developed which using opto-electronic nondestructive testing and virtual instrument techniques. The degree of pathological changes of skin can be detected by this platform also, thus the shortcoming of dosage selection in laser clinical treatments which have been decided only by naked eye observation and past experience of doctors can be solved.

  1. Comparing Face Detection and Recognition Techniques

    OpenAIRE

    Korra, Jyothi

    2016-01-01

    This paper implements and compares different techniques for face detection and recognition. One is find where the face is located in the images that is face detection and second is face recognition that is identifying the person. We study three techniques in this paper: Face detection using self organizing map (SOM), Face recognition by projection and nearest neighbor and Face recognition using SVM.

  2. Structural studies using X-ray absorption and scattering techniques

    International Nuclear Information System (INIS)

    Ericson, Agneta.

    1989-01-01

    The thesis presents extended X-ray absorption fine structure, EXAFS, and large angle X-ray scattering, LAXS, techniques; instrumentation, data collection and reduction, and applications. These techniques have been used to determine the structures of magnesium halides and organomagnesium halides in diethyl ether and tetrahydrofuran solution. The iodides were used for the LAXS measurements and Br K edge EXAFS data were collected for the corresponding bromides. Two different complexes are present in the diethyl ether solution of magnesium iodide; a polymeric chain-type structure where magnesium is tetrahedrally coordinated, as well as dimeric complex with octahedrally coordinated magnesium. Solvated MgI + is the dominating species in tetrahydrofuran solution. The organomagnesium halides are present in diethyl ether solution as both solvated monomeric and dimeric complexes. Magnesium coordinates a halide ion, an alkyl or aryl group and four solvent molecules octahedrally in the monomeric complex. In the dimeric complex magnesium is octahedrally coordinated by two bridging halide ions, an alkyl or aryl group and three solvent molecules. The distribution of monomeric and dimeric complexes in various solutions are given by a dimerisation constant, K dl . The results indicate that the Schlenk equilibrium is present in these solutions, however, in an extended form. In diethyl ether solution, where MgX 2 does not dissociate, no MgX 2 complex and thereby no Schlenk equilibrium has been observed. In tetrahydrofuran solution MgI 2 has dissociated into mainly MgI + and I - . This indicates that the concentration of MgI 2 is low and that the Schlenk equilibrium should be expanded even further to include the dissociation equilibrium of the magnesium halide. In the thesis Fe K edge EXAFS data collected for the semireduced form of protein A of methane monooxygenase from Methylococcus capsulatus, are also presented. (139 refs.)

  3. A CCD-based system for the detection of DNA in electrophoresis gels by UV absorption

    International Nuclear Information System (INIS)

    Mahon, A.R.; MacDonald, J.H.; Mainwood, A.; Ott, R.J.

    1999-01-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled nucleic acids in agarose gels is presented. The technique is based on ultraviolet (UV) absorption by nucleotides. A deuterium source illuminates individual sample lanes of an electrophoresis gel via an array of optical fibres. As DNA bands pass through the illuminated region of the gel the amount of UV light transmitted is reduced because of absorption by the DNA. During electrophoresis the regions of DNA are detected on-line using a UV-sensitive charge coupled device (CCD). As the absorption coefficient is proportional to the mass of DNA the technique is inherently quantitative. The mass of DNA in a region of the gel is approximately proportional to the integrated signal in the corresponding section of the CCD image. This system currently has a detection limit of less than 1.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. In addition the DNA sample remains in its native state. The removal of the carcinogenic dye from the detection procedure greatly reduces associated biological hazards. (author)

  4. Airborne Measurements of CO2 Column Absorption and Range Using a Pulsed Direct-Detection Integrated Path Differential Absorption Lidar

    Science.gov (United States)

    Abshire, James B.; Riris, Haris; Weaver, Clark J.; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Browell, Edward V.

    2013-01-01

    We report on airborne CO2 column absorption measurements made in 2009 with a pulsed direct-detection lidar operating at 1572.33 nm and utilizing the integrated path differential absorption technique. We demonstrated these at different altitudes from an aircraft in July and August in flights over four locations in the central and eastern United States. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The lidar measurement statistics were also calculated for each flight as a function of altitude. The optical depth varied nearly linearly with altitude, consistent with calculations based on atmospheric models. The scatter in the optical depth measurements varied with aircraft altitude as expected, and the median measurement precisions for the column varied from 0.9 to 1.2 ppm. The altitude range with the lowest scatter was 810 km, and the majority of measurements for the column within it had precisions between 0.2 and 0.9 ppm.

  5. Accelerator based techniques for contraband detection

    Science.gov (United States)

    Vourvopoulos, George

    1994-05-01

    It has been shown that narcotics, explosives, and other contraband materials, contain various chemical elements such as H, C, N, O, P, S, and Cl in quantities and ratios that differentiate them from each other and from other innocuous substances. Neutrons and γ-rays have the ability to penetrate through various materials at large depths. They are thus able, in a non-intrusive way, to interrogate volumes ranging from suitcases to Sea-Land containers, and have the ability to image the object with an appreciable degree of reliability. Neutron induced reactions such as (n, γ), (n, n') (n, p) or proton induced γ-resonance absorption are some of the reactions currently investigated for the identification of the chemical elements mentioned above. Various DC and pulsed techniques are discussed and their advantages, characteristics, and current progress are shown. Areas where use of these methods is currently under evaluation are detection of hidden explosives, illicit drug interdiction, chemical war agents identification, nuclear waste assay, nuclear weapons destruction and others.

  6. Inverse Raman effect: applications and detection techniques

    International Nuclear Information System (INIS)

    Hughes, L.J. Jr.

    1980-08-01

    The processes underlying the inverse Raman effect are qualitatively described by comparing it to the more familiar phenomena of conventional and stimulated Raman scattering. An experession is derived for the inverse Raman absorption coefficient, and its relationship to the stimulated Raman gain is obtained. The power requirements of the two fields are examined qualitatively and quantitatively. The assumption that the inverse Raman absorption coefficient is constant over the interaction length is examined. Advantages of the technique are discussed and a brief survey of reported studies is presented

  7. Inverse Raman effect: applications and detection techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, L.J. Jr.

    1980-08-01

    The processes underlying the inverse Raman effect are qualitatively described by comparing it to the more familiar phenomena of conventional and stimulated Raman scattering. An experession is derived for the inverse Raman absorption coefficient, and its relationship to the stimulated Raman gain is obtained. The power requirements of the two fields are examined qualitatively and quantitatively. The assumption that the inverse Raman absorption coefficient is constant over the interaction length is examined. Advantages of the technique are discussed and a brief survey of reported studies is presented.

  8. Hlaallele Detection Using Molecular Techniques

    Directory of Open Access Journals (Sweden)

    Philip A. Dyer

    1993-01-01

    Full Text Available There are now many molecular biological techniques available to define HLA class I and class II alleles. Some of these are also applicable to other human polymorphic genes, in particular to those non-HLA genes encoded within the Mhc. The range of techniques available allows laboratories to choose those most suited to their purpose. The routine laboratory supporting solid organ transplants will need to type large numbers of potential recipients over a period of time, probably using PCR-SSOP while donors will be typed singly and rapidly using PCR-SSP with HLA allele compatibility determined by heteroduplex analysis. Laboratories supporting bone marrow transplantation, where time is less pressing, can choose from the whole range of techniques to determine accurately donor recipient Mhc compatibility. For disease studies, techniques defining precise HLA allele sequence polymorphisms are needed and high sample numbers have to be accommodated. When an association is established allele sequencing has to be used. In the near future, the precise role of HLA alleles in transplantation and disease susceptibility is likely to be established unambiguously.

  9. Uranium Detection - Technique Validation Report

    Energy Technology Data Exchange (ETDEWEB)

    Colletti, Lisa Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Garduno, Katherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Lujan, Elmer J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Mechler-Hickson, Alexandra Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Univ. of Wisconsin, Madison, WI (United States); May, Iain [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division; Reilly, Sean Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division

    2016-04-14

    As a LANL activity for DOE/NNSA in support of SHINE Medical Technologies™ ‘Accelerator Technology’ we have been investigating the application of UV-vis spectroscopy for uranium analysis in solution. While the technique has been developed specifically for sulfate solutions, the proposed SHINE target solutions, it can be adapted to a range of different solution matrixes. The FY15 work scope incorporated technical development that would improve accuracy, specificity, linearity & range, precision & ruggedness, and comparative analysis. Significant progress was achieved throughout FY 15 addressing these technical challenges, as is summarized in this report. In addition, comparative analysis of unknown samples using the Davies-Gray titration technique highlighted the importance of controlling temperature during analysis (impacting both technique accuracy and linearity/range). To fully understand the impact of temperature, additional experimentation and data analyses were performed during FY16. The results from this FY15/FY16 work were presented in a detailed presentation, LA-UR-16-21310, and an update of this presentation is included with this short report summarizing the key findings. The technique is based on analysis of the most intense U(VI) absorbance band in the visible region of the uranium spectra in 1 M H2SO4, at λmax = 419.5 nm.

  10. Ambient air contamination: Characterization and detection techniques

    Science.gov (United States)

    Nulton, C. P.; Silvus, H. S.

    1985-01-01

    Techniques to characterize and detect sources of ambient air contamination are described. Chemical techniques to identify indoor contaminants are outlined, they include gas chromatography, or colorimetric detection. Organics generated from indoor materials at ambient conditions and upon combustion are characterized. Piezoelectric quartz crystals are used as precision frequency determining elements in electronic oscillators.

  11. Valence-to-core-detected X-ray absorption spectroscopy

    DEFF Research Database (Denmark)

    Hall, Eleanor R.; Pollock, Christopher J.; Bendix, Jesper

    2014-01-01

    X-ray absorption spectroscopy (XAS) can provide detailed insight into the electronic and geometric structures of transition-metal active sites in metalloproteins and chemical catalysts. However, standard XAS spectra inherently represent an average contribution from the entire coordination...... environment with limited ligand selectivity. To address this limitation, we have investigated the enhancement of XAS features using valence-to-core (VtC)-detected XAS, whereby XAS spectra are measured by monitoring fluorescence from valence-to-core X-ray emission (VtC XES) events. VtC emission corresponds...... to transitions from filled ligand orbitals to the metal 1s core hole, with distinct energetic shifts for ligands of differing ionization potentials. VtC-detected XAS data were obtained from multiple valence emission features for a series of well-characterized Mn model compounds; taken together, these data...

  12. Landmine detection by nuclear techniques

    Energy Technology Data Exchange (ETDEWEB)

    Megahid, R M [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt)

    2000-11-15

    According to the information given by recent published data , more than 150 million land mines are buried in more than 70 countries, among them is Egypt . In Egypt, more than 23 million land mines lie buried in the northern parts of the western desert and western parts of Sinai . These mines are triggered accidentally by civilian activities, ravaging the land and killing or maiming a lot of innocent civilian people . For humanitarian demining , the removal of land mines already in the ground is very difficult and quite costly. In addition, detecting minimum metal antipersonnel mines and distinguishing them from the metallic debris of a minefields is difficult with current available detectors.

  13. Landmine detection by nuclear techniques

    International Nuclear Information System (INIS)

    Megahid, R.M.

    2000-01-01

    According to the information given by recent published data , more than 150 million land mines are buried in more than 70 countries, among them is Egypt . In Egypt, more than 23 million land mines lie buried in the northern parts of the western desert and western parts of Sinai . These mines are triggered accidentally by civilian activities, ravaging the land and killing or maiming a lot of innocent civilian people . For humanitarian demining , the removal of land mines already in the ground is very difficult and quite costly. In addition, detecting minimum metal antipersonnel mines and distinguishing them from the metallic debris of a minefields is difficult with current available detectors

  14. [Gas pipeline leak detection based on tunable diode laser absorption spectroscopy].

    Science.gov (United States)

    Zhang, Qi-Xing; Wang, Jin-Jun; Liu, Bing-Hai; Cai, Ting-Li; Qiao, Li-Feng; Zhang, Yong-Ming

    2009-08-01

    The principle of tunable diode laser absorption spectroscopy and harmonic detection technique was introduced. An experimental device was developed by point sampling through small multi-reflection gas cell. A specific line near 1 653. 7 nm was targeted for methane measurement using a distributed feedback diode laser as tunable light source. The linearity between the intensity of second harmonic signal and the concentration of methane was determined. The background content of methane in air was measured. The results show that gas sensors using tunable diode lasers provide a high sensitivity and high selectivity method for city gas pipeline leak detection.

  15. Wavelength modulation spectroscopy--digital detection of gas absorption harmonics based on Fourier analysis.

    Science.gov (United States)

    Mei, Liang; Svanberg, Sune

    2015-03-20

    This work presents a detailed study of the theoretical aspects of the Fourier analysis method, which has been utilized for gas absorption harmonic detection in wavelength modulation spectroscopy (WMS). The lock-in detection of the harmonic signal is accomplished by studying the phase term of the inverse Fourier transform of the Fourier spectrum that corresponds to the harmonic signal. The mathematics and the corresponding simulation results are given for each procedure when applying the Fourier analysis method. The present work provides a detailed view of the WMS technique when applying the Fourier analysis method.

  16. Analytical detection techniques for droplet microfluidics—A review

    International Nuclear Information System (INIS)

    Zhu, Ying; Fang, Qun

    2013-01-01

    Graphical abstract: -- Highlights: •This is the first review paper focused on the analytical techniques for droplet-based microfluidics. •We summarized the analytical methods used in droplet-based microfluidic systems. •We discussed the advantage and disadvantage of each method through its application. •We also discuss the future development direction of analytical methods for droplet-based microfluidic systems. -- Abstract: In the last decade, droplet-based microfluidics has undergone rapid progress in the fields of single-cell analysis, digital PCR, protein crystallization and high throughput screening. It has been proved to be a promising platform for performing chemical and biological experiments with ultra-small volumes (picoliter to nanoliter) and ultra-high throughput. The ability to analyze the content in droplet qualitatively and quantitatively is playing an increasing role in the development and application of droplet-based microfluidic systems. In this review, we summarized the analytical detection techniques used in droplet systems and discussed the advantage and disadvantage of each technique through its application. The analytical techniques mentioned in this paper include bright-field microscopy, fluorescence microscopy, laser induced fluorescence, Raman spectroscopy, electrochemistry, capillary electrophoresis, mass spectrometry, nuclear magnetic resonance spectroscopy, absorption detection, chemiluminescence, and sample pretreatment techniques. The importance of analytical detection techniques in enabling new applications is highlighted. We also discuss the future development direction of analytical detection techniques for droplet-based microfluidic systems

  17. Edge detection techniques for iris recognition system

    International Nuclear Information System (INIS)

    Tania, U T; Motakabber, S M A; Ibrahimy, M I

    2013-01-01

    Nowadays security and authentication are the major parts of our daily life. Iris is one of the most reliable organ or part of human body which can be used for identification and authentication purpose. To develop an iris authentication algorithm for personal identification, this paper examines two edge detection techniques for iris recognition system. Between the Sobel and the Canny edge detection techniques, the experimental result shows that the Canny's technique has better ability to detect points in a digital image where image gray level changes even at slow rate

  18. The renewed absorption refrigerating engineering; Le groupe frigorifique a absorption, technique d`avenir?

    Energy Technology Data Exchange (ETDEWEB)

    Roumajon, J. [BETM (Country unknown/Code not available)

    1998-04-01

    This article reviews the characteristics of a refrigerating unit based on absorption. The main advantages are: silence, no vibration, security (no pressure, no inflammable and toxic gas), and a broad range of energy sources can be used (solar, geothermal, natural gas). The main disadvantages compared to a current compression cooling machine are: low yield, important volume of equipment, high cost and great amount of heat released. An installation based on a lithium bromide-water mixture is described, the role played by the different parts of the installation is explained. (A.C.)

  19. Understanding refraction contrast using a comparison of absorption and refraction computed tomographic techniques

    Science.gov (United States)

    Wiebe, S.; Rhoades, G.; Wei, Z.; Rosenberg, A.; Belev, G.; Chapman, D.

    2013-05-01

    Refraction x-ray contrast is an imaging modality used primarily in a research setting at synchrotron facilities, which have a biomedical imaging research program. The most common method for exploiting refraction contrast is by using a technique called Diffraction Enhanced Imaging (DEI). The DEI apparatus allows the detection of refraction between two materials and produces a unique ''edge enhanced'' contrast appearance, very different from the traditional absorption x-ray imaging used in clinical radiology. In this paper we aim to explain the features of x-ray refraction contrast as a typical clinical radiologist would understand. Then a discussion regarding what needs to be considered in the interpretation of the refraction image takes place. Finally we present a discussion about the limitations of planar refraction imaging and the potential of DEI Computed Tomography. This is an original work that has not been submitted to any other source for publication. The authors have no commercial interests or conflicts of interest to disclose.

  20. Techniques for detecting explosives and contraband

    International Nuclear Information System (INIS)

    Vourvopoulos, G.

    1994-01-01

    Because terrorism continues to be a societal threat, scientists are still searching for ways to identify concealed weapons that can be used in terrorist attacks. Explosives are singled out for particular attention because they can easily be shaped to look innocuous, and are still hard to detect. At present, there are three methods under development for the detection of explosives: X-ray imaging, vapour detection and nuclear techniques, and this article will concentrate on the latter. Since there is no single technology that can address all the questions concerning the detection of explosives and other illicit contraband, the philosophy that emerges is that of an integral system combining methodologies. Such a system could contain a nuclear technology device, a vapour detector, and an X-ray imaging device, all backed by an intelligence gathering system. In this paper methods are suggested for identifying explosives which may be used in terrorist attacks and for detecting concealed drugs. Techniques discussed are X-ray imaging, combining high and low energy x-ray machines, vapour detection using a ''sniffer'' to collect vapour samples then analysing the vapour by gas chromatography, chemiluminescence and mass spectroscopy and nuclear techniques. Nuclear techniques, such as neutron activation analysis, are discussed in detail but it is stressed that they need to be carried out at speed to eliminate disruption and delay at airports etc. (UK)

  1. Tunable Diode Laser Atomic Absorption Spectroscopy for Detection of Potassium under Optically Thick Conditions.

    Science.gov (United States)

    Qu, Zhechao; Steinvall, Erik; Ghorbani, Ramin; Schmidt, Florian M

    2016-04-05

    Potassium (K) is an important element related to ash and fine-particle formation in biomass combustion processes. In situ measurements of gaseous atomic potassium, K(g), using robust optical absorption techniques can provide valuable insight into the K chemistry. However, for typical parts per billion K(g) concentrations in biomass flames and reactor gases, the product of atomic line strength and absorption path length can give rise to such high absorbance that the sample becomes opaque around the transition line center. We present a tunable diode laser atomic absorption spectroscopy (TDLAAS) methodology that enables accurate, calibration-free species quantification even under optically thick conditions, given that Beer-Lambert's law is valid. Analyte concentration and collisional line shape broadening are simultaneously determined by a least-squares fit of simulated to measured absorption profiles. Method validation measurements of K(g) concentrations in saturated potassium hydroxide vapor in the temperature range 950-1200 K showed excellent agreement with equilibrium calculations, and a dynamic range from 40 pptv cm to 40 ppmv cm. The applicability of the compact TDLAAS sensor is demonstrated by real-time detection of K(g) concentrations close to biomass pellets during atmospheric combustion in a laboratory reactor.

  2. Surface extended x-ray absorption fine structure of low-Z absorbates using fluorescence detection

    International Nuclear Information System (INIS)

    Stoehr, J.; Kollin, E.B.; Fischer, D.A.; Hastings, J.B.; Zaera, F.; Sette, F.

    1985-05-01

    Comparison of x-ray fluorescence yield (FY) and electron yield surface extended x-ray absorption fine structure spectra above the S K-edge for c(2 x 2) S on Ni(100) reveals an order of magnitude higher sensitivity of the FY technique. Using FY detection, thiophene (C 4 H 4 S) chemisorption on Ni(100) is studied with S coverages down to 0.08 monolayer. The molecule dissociates at temperatures as low as 100K by interaction with fourfold hollow Ni sites. Blocking of these sites by oxygen leaves the molecule intact

  3. Biosensing Using Magnetic Particle Detection Techniques

    Directory of Open Access Journals (Sweden)

    Yi-Ting Chen

    2017-10-01

    Full Text Available Magnetic particles are widely used as signal labels in a variety of biological sensing applications, such as molecular detection and related strategies that rely on ligand-receptor binding. In this review, we explore the fundamental concepts involved in designing magnetic particles for biosensing applications and the techniques used to detect them. First, we briefly describe the magnetic properties that are important for bio-sensing applications and highlight the associated key parameters (such as the starting materials, size, functionalization methods, and bio-conjugation strategies. Subsequently, we focus on magnetic sensing applications that utilize several types of magnetic detection techniques: spintronic sensors, nuclear magnetic resonance (NMR sensors, superconducting quantum interference devices (SQUIDs, sensors based on the atomic magnetometer (AM, and others. From the studies reported, we note that the size of the MPs is one of the most important factors in choosing a sensing technique.

  4. Techniques for detection of transition phases in calcined alumina

    International Nuclear Information System (INIS)

    Pandolfelli, V.C.; Folgueras-Dominguez, S.

    1987-01-01

    Detection of transition phases in alumina, is very important in the receiving control and calcination of aluminium hydroxide. The non alfa or transition phases difficults the processability and causes localized shrinkage on sintering compromising the dimensional and mechanical aspects of the product. In this research using refraction index, absorption of dyes, specific density, X-ray diffraction and scanning electron microscopy, analyses, are done in calcined hydroxides submited to different thermal treatments. The limits and facilities of each technique are discussed and compared. (Author) [pt

  5. Determination of Mercury in an Assortment of Dietary Supplements Using an Inexpensive Combustion Atomic Absorption Spectrometry Technique

    OpenAIRE

    Levine, Keith E.; Levine, Michael A.; Weber, Frank X.; Hu, Ye; Perlmutter, Jason; Grohse, Peter M.

    2005-01-01

    The concentrations of mercury in forty, commercially available dietary supplements, were determined using a new, inexpensive analysis technique. The method involves thermal decomposition, amalgamation, and detection of mercury by atomic absorption spectrometry with an analysis time of approximately six minutes per sample. The primary cost savings from this approach is that labor-intensive sample digestion is not required prior to analysis, further automating the analytical procedure. As a res...

  6. 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

  7. IMAGE ANALYSIS BASED ON EDGE DETECTION TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    纳瑟; 刘重庆

    2002-01-01

    A method that incorporates edge detection technique, Markov Random field (MRF), watershed segmentation and merging techniques was presented for performing image segmentation and edge detection tasks. It first applies edge detection technique to obtain a Difference In Strength (DIS) map. An initial segmented result is obtained based on K-means clustering technique and the minimum distance. Then the region process is modeled by MRF to obtain an image that contains different intensity regions. The gradient values are calculated and then the watershed technique is used. DIS calculation is used for each pixel to define all the edges (weak or strong) in the image. The DIS map is obtained. This help as priority knowledge to know the possibility of the region segmentation by the next step (MRF), which gives an image that has all the edges and regions information. In MRF model,gray level l, at pixel location i, in an image X, depends on the gray levels of neighboring pixels. The segmentation results are improved by using watershed algorithm. After all pixels of the segmented regions are processed, a map of primitive region with edges is generated. The edge map is obtained using a merge process based on averaged intensity mean values. A common edge detectors that work on (MRF) segmented image are used and the results are compared. The segmentation and edge detection result is one closed boundary per actual region in the image.

  8. Improvement of the tetrachloromercurate absorption technique for measuring low atmospheric SO2 mixing ratios

    Science.gov (United States)

    Jaeschke, W.; Beltz, N.; Haunold, W.; Krischke, U.

    1997-07-01

    During the Gas-Phase Sulfur Intercomparison Experiment (GASIE) in 1994 an analytical system for measuring sulfur dioxide mixing ratios at low parts per trillion (pptv) levels was employed. It is based on the absorption of SO2 on a tetrachloromercurate(II)-impregnated filter. The subsequent analysis uses a chemiluminescence reaction by treating the resulting disulfitomercurate(II) complex with an acidic cerium sulfate solution. An improved sampling device has been introduced that increases the maximum sampling volume from 200 L to 500 L. It is also possible to determine the blank value accurately for each sample. The absorption efficiency of the sampling system is 98.7±6.4% at a nominal flow rate of 10 L/min. The calculated (3σ) detection limit is 3±1 pptv SO2. The sample solution is stable for up to 30 days, which allows the samples to be safely stored or shipped before analysis. This permits the use of a sensitive, compact, and reliable sampling system in the field with subsequent analysis under optimal conditions in the laboratory. A continuous flow chemiluminescence (CFCL) analyzer for on-line measurements is also presented. The system is based on the same chemical principles as the described filter technique.

  9. Normal blood magnesium levels in volunteers of Rawalpindi by atomic absorption absorption technique

    International Nuclear Information System (INIS)

    Ahmed, I.; Rehman, S.; Yawar, W.; Rusheed, A.; Ahraf, M.; Syed, N.H.

    1999-01-01

    Magnesium levels in whole blood samples of 67 healthy volunteers (mean 6.46 -+ 0.221; range 1.345 - 13.163 mg/dL) of Rawalpindi district have been determined by flame atomic absorption spectrophotometric method. Magnesium levels of 41 male and 26 female subjects including doctors, nurses, patients attendees, medical students, sweepers and peons of Rawalpindi Medical College and Rawalpindi General Hospital revealed the normal mean blood levels of 6.088 - + 0.258 mg/dL (range 1.345 - 10.679 mg/dL)and 7.060 -+ 0.375 mg/dL (range 4.495 - 13.163 mg/dL),P<0.05 respectively. Only 10 male volunteers were smokers exhibiting 6.768 -+ 0.558 mg/dL (range 4.466 -10.679 mg/dL). Significant relationship was found in magnesium levels between males and females of poor socio-economic group (P<0.05). No relationship occurred between male smokers and non-smokers and magnesium levels in the age groups of males or females or both, when data was compared by 't' test. (author)

  10. Measurement of water absorption capacity in wheat flour by a headspace gas chromatographic technique.

    Science.gov (United States)

    Xie, Wei-Qi; Yu, Kong-Xian; Gong, Yi-Xian

    2018-04-17

    The purpose of this work is to introduce a new method for quantitatively analyzing water absorption capacity in wheat flour by a headspace gas chromatographic technique. This headspace gas chromatographic technique was based on measuring the water vapor released from a series of wheat flour samples with different contents of water addition. According to the different trends between the vapor and wheat flour phase before and after the water absorption capacity in wheat flour, a turning point (corresponding to water absorption capacity in wheat flour) can be obtained by fitting the data of the water gas chromatography peak area from different wheat flour samples. The data showed that the phase equilibrium in the vial can be achieved in 25 min at desired temperature (35°C). The relative standard deviation of the reaction headspace gas chromatographic technique in water absorption capacity determination was within 3.48%, the relative differences has been determined by comparing the water absorption capacity obtained from this new analytical technique with the data from the reference technique (i.e., the filtration method), which are less than 8.92%. The new headspace gas chromatographic method is automated, accurate and be a reliable tool for quantifying water absorption capacity in wheat flour in both laboratory research and mill applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. An Insight Into the Two Costing Technique: Absorption Costing and Marginal Costing

    OpenAIRE

    Mariam Nawaz

    2013-01-01

    This paper will investigate the controversy that is innate between the two costing techniques; Absorption Costing and Marginal Costing and would throw light on which costing technique better serves its purpose in helping management for decision making process and if Marginal Costing technique is concluded as better technique then why it should not be used for external reporting purpose. This paper will only crystallize and highlight the issues descriptively and will not resolve the issues tha...

  12. Multipath Detection Using Boolean Satisfiability Techniques

    Directory of Open Access Journals (Sweden)

    Fadi A. Aloul

    2011-01-01

    Full Text Available A new technique for multipath detection in wideband mobile radio systems is presented. The proposed scheme is based on an intelligent search algorithm using Boolean Satisfiability (SAT techniques to search through the uncertainty region of the multipath delays. The SAT-based scheme utilizes the known structure of the transmitted wideband signal, for example, pseudo-random (PN code, to effectively search through the entire space by eliminating subspaces that do not contain a possible solution. The paper presents a framework for modeling the multipath detection problem as a SAT application. It also provides simulation results that demonstrate the effectiveness of the proposed scheme in detecting the multipath components in frequency-selective Rayleigh fading channels.

  13. Wet bar detection by using water absorption detector

    International Nuclear Information System (INIS)

    Kim, Hee Soo; Bae, Yong Chae; Kee, Chang Doo

    2008-01-01

    Water leaks in water-cooled generator stator windings can generate serious accidents such as insulation breakdown and result in unexpected sudden outages. Thus, it is important to diagnose their water absorption for effective operation of the power plant. Especially, since the capacitance values that are measured for diagnosis are very small so special diagnosis methods like stochastic theory are needed. KEPRI developed a more advanced water absorption detector and diagnosis technology for it. They were applied to a real system and the results of the water absorption test for stator windings agree with the water leak test

  14. Kinetic and Diagnostic Studies of Molecular Plasmas Using Laser Absorption Techniques

    International Nuclear Information System (INIS)

    Welzel, S; Rousseau, A; Davies, P B; Roepcke, J

    2007-01-01

    Within the last decade mid infrared absorption spectroscopy between 3 and 20 μm, known as Infrared Laser Absorption Spectroscopy (IRLAS) and based on tuneable semiconductor lasers, namely lead salt diode lasers, often called tuneable diode lasers (TDL), and quantum cascade lasers (QCL) has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry of molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, organo-silicon and boron compounds has lead to further applications of IRLAS because most of these compounds and their decomposition products are infrared active. IRLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species, which is of particular importance for the investigation of reaction kinetics. Information about gas temperature and population densities can also be derived from IRLAS measurements. A variety of free radicals and molecular ions have been detected, especially using TDLs. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of infrared spectroscopic techniques to industrial requirements. The recent development of QCLs offers an attractive new option for the monitoring and control of industrial plasma processes as well as for highly time-resolved studies on the kinetics of plasma processes. The aim of the present article is threefold: (i) to review recent achievements in our understanding of molecular phenomena in plasmas (ii) to report on selected studies of the spectroscopic properties and kinetic behaviour of radicals, and (iii) to describe the current status of advanced instrumentation for TDLAS in the mid infrared

  15. Study of the effect of Chinese medicine on calcium absorption with isotopic tracer technique

    International Nuclear Information System (INIS)

    Hu, S.M.; Mao, X.Y.; Feng, W.Y.; OY, H.; Wang, M.; Xu, D.D.; Zhang, F.; Chai, Z.F.

    2005-01-01

    The present work was undertaken to study the effect of Chinese medicine on calcium absorption. Female Wistar rats, 3 months old, weighing 250-275 g, were randomly divided into ten groups of 5 rats each. The rats were individually housed in stainless steel metabolic cages in an environmentally controlled room (temperature, 20 degree C; relative humidity, 30%-60%; reversed light : dark cycle, 12:12 hr). Isotopic tracer technique was conducted to study the absorption of calcium acetate and calcium acetate + Chinese medicine in rats. The two calcium supplements were irradiated in a nuclear reactor for 4.95 d at neutron flux of φ=6.1 x 10 13 n/cm 2 ·s. Then they were prepared from concentrated 47 Ca solution (10 mg/ml) with cyclodextrin. The animals received oral doses of 25 mg calcium as calcium acetate or calcium acetate + Chinese medicine via an intragastric gavage. The animals were fasted overnight preceding and food was resumed 3 hrs after the gavage. Blood, heart, lung, liver, spleen, stomach, kidney, small intestine, large intestine and femur samples of the rats were taken upon sacrifice at 0.5, 1, 2, 4, 12, 24, 48, 72, 120, 168 hrs after dosing and assayed for 47 Ca. Urine and feces samples were collected separately after dosing and assayed for 47 Ca. The radioactivity of the samples was counted with a high pure Ge detector and a PC-based Ortec MCA. Its energy resolution was l.85 keV at 1332.5 keV and the relative detection efficiency was 30 %. The dead time was controlled within 10 % to reduce the count loss. Weighed 47 CaCO 3 was used as reference materials. A big distance between the samples and detector was kept to overcome the geometric effect caused by different shape and size of the samples. The gamma energy spectra were analyzed with a multipurpose gamma ray spectrum analysis software package. The parameters were evaluated by means of general linear model, using analysis of covariance with SAS 6.12 for Windows. The results showed that peroral 47 Ca was

  16. Determination of metallic elements in water by the combined preconcentration techniques of ion exchange and atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Paula, M.H. de.

    1981-01-01

    Having as an aim the utilization of atomic absorption method with flame's excitement, the limits of detection in water of six metals (Ag, Co, Cr, Cu, Ni, Zn) were determined in synthetical samples through atomic absorption spectroscopy. Techniques to optimize the data have been pointed out and presented their statistical treatment. By means of the routine and the addition methods three 'real' samples have also been analysed in order to determine the contents of Cu and Zn. Aiming a pre-concentration and by utilizing the 60 Co obtained activating a sample of cobalt in the CDTN/NUCLEBRAS TRIGA MARK-I reactor, the retainement of this cobalt in ion exchange resin and the variation of the factor of elution within different concentration of HCl in water have been determined. The limits of detection are presented and so are the quantitative ones, with and without pre-concentration in an ion exchanger resin and latter elution. (Author) [pt

  17. Thermionic detection of the ionic fragments of continiuum-state pair absorption systems

    International Nuclear Information System (INIS)

    Hotop, R.; Niemax, K.; Richter, J.; Weber, K.H.

    1981-01-01

    Using a thermionic diode we have detected the ionic fragments formed by associative ionization and dissociation after continuum-state pair absorption processes in Cs-Cs and Cs-K systems. Assuming an ionization probability of unity of the excited species and calibrating the pair absorption bands by taking into account the known photoionization cross section of the atoms we found excellent agreement with data from classical absorption measurements. (orig.)

  18. A mid-infrared absorption diagnostic for acetylene detection

    KAUST Repository

    KC, Utsav

    2015-05-14

    Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm−1 over a wide range of temperatures (1000–2200 K) and pressures (1–5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene. © 2015 Springer-Verlag Berlin Heidelberg

  19. Technique for ship/wake detection

    Science.gov (United States)

    Roskovensky, John K [Albuquerque, NM

    2012-05-01

    An automated ship detection technique includes accessing data associated with an image of a portion of Earth. The data includes reflectance values. A first portion of pixels within the image are masked with a cloud and land mask based on spectral flatness of the reflectance values associated with the pixels. A given pixel selected from the first portion of pixels is unmasked when a threshold number of localized pixels surrounding the given pixel are not masked by the cloud and land mask. A spatial variability image is generated based on spatial derivatives of the reflectance values of the pixels which remain unmasked by the cloud and land mask. The spatial variability image is thresholded to identify one or more regions within the image as possible ship detection regions.

  20. Detecting Internet Worms Using Data Mining Techniques

    Directory of Open Access Journals (Sweden)

    Muazzam Siddiqui

    2008-12-01

    Full Text Available Internet worms pose a serious threat to computer security. Traditional approaches using signatures to detect worms pose little danger to the zero day attacks. The focus of malware research is shifting from using signature patterns to identifying the malicious behavior displayed by the malwares. This paper presents a novel idea of extracting variable length instruction sequences that can identify worms from clean programs using data mining techniques. The analysis is facilitated by the program control flow information contained in the instruction sequences. Based upon general statistics gathered from these instruction sequences we formulated the problem as a binary classification problem and built tree based classifiers including decision tree, bagging and random forest. Our approach showed 95.6% detection rate on novel worms whose data was not used in the model building process.

  1. Atmospheric Pre-Corrected Differential Absorption Techniques to Retrieve Columnar Water Vapor: Application to AVIRIS 91/95 Data

    Science.gov (United States)

    Schlaepfer, Daniel; Borel, Christoph C.; Keller, Johannes; Itten, Klaus I.

    1996-01-01

    Water vapor is one of the main forces for weather development as well as for mesoscale air transport processes. The monitoring of water vapor is therefore an important aim in remote sensing of the atmosphere. Current operational systems for water vapor detection use primarily the emission in the thermal infrared (AVHRR, GOES, ATSR, Meteosat) or in the microwave radiation bands (DMSP). The disadvantage of current satellite systems is either a coarse spatial (horizontal) resolution ranging from one to tens of kilometers or a limited insight into the lower atmosphere. Imaging spectrometry on the other hand measures total column water vapor contents at a high spatial horizontal resolution and has therefore the potential of filling these gaps. The sensors of the AVIRIS instrument are capable of acquiring hyperspectral data in 224 bands located in the visible and near infrared at 10 nm resolution. This data includes the information on constituents of the earth's surface as well as of the atmosphere. The optical measurement of water vapor can be performed using sensor channels located in bands or lines of the absorption spectrum. The AVIRIS sensor has been used to retrieve water vapor and with less accuracy carbon dioxide, oxygen and ozone. To retrieve the water vapor amount, the so called differential absorption technique has been applied. The goal of this technique is to eliminate background factors by taking a ratio between channels within the absorption band and others besides the band. Various ratioing methods on the basis of different channels and calculation techniques were developed. The influence of a trace gas of interest on the radiance at the sensor level is usually simulated by using radiative transfer codes. In this study, the spectral transmittance and radiance are calculated by MODTRAN3 simulations with the new DISORT option. The objective of this work is to test the best performing differential absorption techniques for imaging spectrometry of

  2. Atmospheric pre-corrected differential absorption techniques to retrieve columnar water vapor: Application to AVIRIS 91/95 data

    Energy Technology Data Exchange (ETDEWEB)

    Schlaepfer, D. [Univ. of Zuerich (Switzerland). Dept. of Geography; Borel, C.C. [Los Alamos National Lab., NM (United States); Keller, J. [Paul Scherrer Institut, Villigen (Switzerland)] [and others

    1996-03-01

    Water vapor is one of the main forces for weather development as well as for mesoscale air transport processes. The monitoring of water vapor is therefore an important aim in remote sensing of the atmosphere. Current operational systems for water vapor detection use primarily the emission in the thermal infrared (AVHRR, GOES, ATSR, Meteosat) or in the microwave radiation bands (DMSP). The disadvantage of current satellite systems is either a coarse spatial (horizontal) resolution ranging from one to tens of kilometers or a limited insight into the lower atmosphere. Imaging spectrometry on the other hand measures total column water vapor contents at a high spatial horizontal resolution and has therefore the potential of filling these gaps. The sensors of the AVIRIS instrument are capable of acquiring hyperspectral data in 224 bands located in the visible and near infrared at 10 run resolution. This data includes information on constituents of the earth`s surface as well as of the atmosphere. The optical measurement of water vapor can be performed using sensor channels located in bands or lines of the absorption spectrum. The AVIRIS sensor has been used to retrieve water vapor and with less accuracy carbon dioxide, oxygen and ozone. To retrieve the water vapor amount, the so called differential absorption technique has been applied. The goal of this technique is to eliminate background factors by taking a ratio between channels within the absorption band and others besides the band. Various rationing methods on the basis of different channels and calculation techniques were developed. The influence of a trace gas of interest on the radiance at the sensor level is usually simulated by using radiative transfer codes. In this study, spectral transmittance and radiance are calculated by MODTRAN3 simulations with the new DISORT option. This work testS the best performing differential absorption techniques for imaging spectrometry of tropospheric water vapor.

  3. Study of Photosensitive Dry Films Absorption for Printed Circuit Boards by Photoacoustic Technique

    Science.gov (United States)

    Hernández, R.; Zaragoza, J. A. Barrientos; Jiménez-Pérez, J. L.; Orea, A. Cruz; Correa-Pacheco, Z. N.

    2017-08-01

    In this work, the study of photosensitive dry-type films by photoacoustic technique is proposed. The dry film photoresist is resistant to chemical etching for printed circuit boards such as ferric chloride, sodium persulfate or ammonium, hydrochloric acid. It is capable of faithfully reproducing circuit pattern exposed to ultraviolet light (UV) through a negative. Once recorded, the uncured portion is removed with alkaline solution. It is possible to obtain good results in surface mount circuits with tracks of 5 mm. Furthermore, the solid resin films are formed by three layers, two protective layers and a UV-sensitive optical absorption layer in the range of 325 nm to 405 nm. By means of optical absorption of UV-visible rays emitted by a low-power Xe lamp, the films transform this energy into thermal waves generated by the absorption of optical radiation and subsequently no-radiative de-excitation occurs. The photoacoustic spectroscopy is a useful technique to measure the transmittance and absorption directly. In this study, the optical absorption spectra of the three layers of photosensitive dry-type films were obtained as a function of the wavelength, in order to have a knowledge of the absorber layer and the protective layers. These analyses will give us the physical properties of the photosensitive film, which are very important in curing the dry film for applications in printed circuit boards.

  4. Improvement and development of automatic detection techniques

    International Nuclear Information System (INIS)

    Yamada, Kiyomi; Takai, Setsuo; Togashi, Chikako; Itami, Jun

    2000-01-01

    For detection of radiation-induced mutation, establishment of a new sample preparation method and its procedures suitable for its automation is thought to be the key step to improve the detection efficacy and save labor. In this study, an investigation was made on the sensitivity to radiation exposure in respect of the occurrence of chromosomal breakage by high precision chromosome coloring method utilizing FISH. The number of chromosome breakage per cell was determined in chromosome 1, 4, 5, 9, 11 and 13 prepared from an identical sample exposed to three different grays. The breakage number was found to increase linearly as an increase in the amount of chromosomal DNA and hotspots of the radiation-induced breakages tended to concentrate in R band and the position of R band was almost coincident with the sites of chromosomal translocation breakages specific to leukemia, showing a correlation of radiation exposure to leukemia. Chromosome 13, 14 and 15, which were different in band pattern but similar in its length taken from cells exposed to X-ray at 5 Gy were investigated in detail and it was found that the sensitivity of chromosome to radiation was depending on the quantity and the quality of R band in each chromosome. The benefits of this chromosome coloring method for the analysis of chromosome breakage were as follows: when compared with the conventional dicentric method, the kinds of chromosomal abnormalities to be detectable were much more and its detection rate as well as accuracy was higher. In addition, the time required for determination was loess than one tenth of the conventional one. A breakage site was detectable with differences in color tone and thus, any special technique was not necessary. Therefore, the chromosome coloring method by FISH was demonstrated to be much suitable for automatic image analysis by computer. (M.N.)

  5. Combined Acquisition Technique (CAT) for Neuroimaging of Multiple Sclerosis at Low Specific Absorption Rates (SAR)

    Science.gov (United States)

    Biller, Armin; Choli, Morwan; Blaimer, Martin; Breuer, Felix A.; Jakob, Peter M.; Bartsch, Andreas J.

    2014-01-01

    Purpose To compare a novel combined acquisition technique (CAT) of turbo-spin-echo (TSE) and echo-planar-imaging (EPI) with conventional TSE. CAT reduces the electromagnetic energy load transmitted for spin excitation. This radiofrequency (RF) burden is limited by the specific absorption rate (SAR) for patient safety. SAR limits restrict high-field MRI applications, in particular. Material and Methods The study was approved by the local Medical Ethics Committee. Written informed consent was obtained from all participants. T2- and PD-weighted brain images of n = 40 Multiple Sclerosis (MS) patients were acquired by CAT and TSE at 3 Tesla. Lesions were recorded by two blinded, board-certificated neuroradiologists. Diagnostic equivalence of CAT and TSE to detect MS lesions was evaluated along with their SAR, sound pressure level (SPL) and sensations of acoustic noise, heating, vibration and peripheral nerve stimulation. Results Every MS lesion revealed on TSE was detected by CAT according to both raters (Cohen’s kappa of within-rater/across-CAT/TSE lesion detection κCAT = 1.00, at an inter-rater lesion detection agreement of κLES = 0.82). CAT reduced the SAR burden significantly compared to TSE (pCAT were 29.0 (±5.7) % for the T2-contrast and 32.7 (±21.9) % for the PD-contrast (expressed as percentages of the effective SAR limit of 3.2 W/kg for head examinations). Average SPL of CAT was no louder than during TSE. Sensations of CAT- vs. TSE-induced heating, noise and scanning vibrations did not differ. Conclusion T2−/PD-CAT is diagnostically equivalent to TSE for MS lesion detection yet substantially reduces the RF exposure. Such SAR reduction facilitates high-field MRI applications at 3 Tesla or above and corresponding protocol standardizations but CAT can also be used to scan faster, at higher resolution or with more slices. According to our data, CAT is no more uncomfortable than TSE scanning. PMID:24608106

  6. Combined acquisition technique (CAT for neuroimaging of multiple sclerosis at low specific absorption rates (SAR.

    Directory of Open Access Journals (Sweden)

    Armin Biller

    Full Text Available PURPOSE: To compare a novel combined acquisition technique (CAT of turbo-spin-echo (TSE and echo-planar-imaging (EPI with conventional TSE. CAT reduces the electromagnetic energy load transmitted for spin excitation. This radiofrequency (RF burden is limited by the specific absorption rate (SAR for patient safety. SAR limits restrict high-field MRI applications, in particular. MATERIAL AND METHODS: The study was approved by the local Medical Ethics Committee. Written informed consent was obtained from all participants. T2- and PD-weighted brain images of n = 40 Multiple Sclerosis (MS patients were acquired by CAT and TSE at 3 Tesla. Lesions were recorded by two blinded, board-certificated neuroradiologists. Diagnostic equivalence of CAT and TSE to detect MS lesions was evaluated along with their SAR, sound pressure level (SPL and sensations of acoustic noise, heating, vibration and peripheral nerve stimulation. RESULTS: Every MS lesion revealed on TSE was detected by CAT according to both raters (Cohen's kappa of within-rater/across-CAT/TSE lesion detection κCAT = 1.00, at an inter-rater lesion detection agreement of κLES = 0.82. CAT reduced the SAR burden significantly compared to TSE (p<0.001. Mean SAR differences between TSE and CAT were 29.0 (± 5.7 % for the T2-contrast and 32.7 (± 21.9 % for the PD-contrast (expressed as percentages of the effective SAR limit of 3.2 W/kg for head examinations. Average SPL of CAT was no louder than during TSE. Sensations of CAT- vs. TSE-induced heating, noise and scanning vibrations did not differ. CONCLUSION: T2-/PD-CAT is diagnostically equivalent to TSE for MS lesion detection yet substantially reduces the RF exposure. Such SAR reduction facilitates high-field MRI applications at 3 Tesla or above and corresponding protocol standardizations but CAT can also be used to scan faster, at higher resolution or with more slices. According to our data, CAT is no more uncomfortable than TSE scanning.

  7. Electrochemical and Infrared Absorption Spectroscopy Detection of SF₆ Decomposition Products.

    Science.gov (United States)

    Dong, Ming; Zhang, Chongxing; Ren, Ming; Albarracín, Ricardo; Ye, Rixin

    2017-11-15

    Sulfur hexafluoride (SF₆) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF₆ decomposition and ultimately generates several types of decomposition products. These SF₆ decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF₆ decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF₆ gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF₆ decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF₆ gas decomposition and is verified to reliably and accurately detect the gas components and concentrations.

  8. Gamma scan technique for detecting coupon inside the mother pipeline

    International Nuclear Information System (INIS)

    Rasif Mohd Zain; Roslan Yahya; Mohamad Rabaie Shari; Airwan Affandi Mahmood; Mior Ahmad Khusaini Adnan

    2012-01-01

    Many times a year natural gas transmission and distribution companies need to make new connections to pipelines to expand or modify their existing system through hot tapping procedure. This procedure involves the installation of a new pipeline connection while the pipeline remains in service, flowing natural gas under pressure. The hot tap procedure includes attaching a branch connection and valve on the outside of an operating pipeline, and then cutting out the pipe-line wall within the branch and removing the wall section, which is called object of coupon through the valve. During the hot tapping process a critical problems occurred when a coupon fell into the mother pipeline. To overcome this problem, a gamma-ray absorption technique was chosen whereby a mapping technique will be done to detect the coupon position. The technique is non-destructive as it applies Co-60 (5 mCi) as a radioisotope sealed source to emit gamma radiation and a NaI(Tl) scintillation as detector. The result provided a visible representation of density profile inside pipeline where the coupon location can be located. This paper provides the detail of the technique used and presents the result obtained. (author)

  9. Detection of corrosion by radiographic techniques

    International Nuclear Information System (INIS)

    Ahmad, M.; Ashraf, M.M.; Khurshid, U.

    2004-01-01

    Radiation processing technologies are playing an increasing role during manufacturing and subsequent use of everyday products. These technologies are now well established and are extensively practiced in industries, to ensure quality and safety of machinery. Corrosion reduces the operational life of the component, its efficiency and helps generate waste. There is an increasing need to detect and characterize the formation of corrosion in industrial components and assemblies at an early stage. Radiation methods and techniques are applied worldwide to examine defects and corrosion-formation in industrial components. For safety and economic reason, appropriate monitoring of the machinery and industrial components would help reduce accidental risks during operation and avoid production-losses. In the present study, X-ray and neutron-radiography techniques were applied for the inspection and evaluation of corrosion in metallic samples for thickness values of the order of 5 mm or less. Relative contrast at various degrees of metal corrosion product loss was computed theoretical and also measured experimentally by applying radiographic techniques. The relative contrast-sensitivity was also measured in two different ways by X-ray and neutron radiography, to compare the visibility of coarse and fine features. Thick metallic areas, free from sealant and variable paint thickness, were imaged with thermal neutrons beam. Low KV X-rays were also applied for imaging corrosion in metallic components. To optimize exposure-time at low KV in X-ray radiography, a medical film/screen combination was used. X-ray radiography approved to be the more promising technique for imaging of corrosion, as compared to neutron radiography. (author)

  10. New techniques for optical absorption measurement of implanted nanoparticles in float glass

    International Nuclear Information System (INIS)

    Okur, I.; Townsend, P.D.; Chandler, P.J.

    1999-01-01

    New techniques are reported for optical absorption and waveguide loss measurement of copper, gold and silver implanted float glass. Implantations were carried out on the tin face of the float glass since this face is an optical waveguide. Specially made triangle shape masks were used during implantation to study the optical loss-implant length relation. Absorption coefficients were extracted as 2.4 and 1 cm -1 for the gold and silver implants at 633 nm, respectively. These values were found to be implant condition dependent. To analyse the shape of nanoparticles a sandwiched structure was used in an optical absorption measurement set-up in which two guiding faces were put in contact. The sandwiched structure places the colloids at the centre of the optical field distribution rather than on the boundary zone. These experiments have revealed that the copper and the gold particles may have non-spherical shapes, whereas for silver, the formation of spherical nanoparticles is more likely

  11. Chipless RFID design procedure and detection techniques

    CERN Document Server

    Rezaiesarlak, Reza

    2015-01-01

    This book examines the design of chipless RFID systems. The authors begin with the historical development of wireless identification systems and finally arrive at a representation of the chipless RFID system as a block diagram illustration. Chapter 2 is devoted to the theoretical bases for the design of chipless RFID tags and detection techniques in the reader. A rigorous mathematical formulation is presented based on the singularity expansion method (SEM) and characteristic mode theory (CMT) in order to study the scattered fields from an object in a general form. Th e authors attempt to explain some physical concepts behind the mathematical descriptions of the theories in this chapter. In Chapter 3, two design procedures based on complex natural resonance and CMT are presented for the design of the chipless RFID tag. By studying the effects of structural parameters on radiation and resonant behaviors of the tag, some design conclusions are presented in this chapter. Chapter 4 is dedicated to the time-frequen...

  12. Radiation detection technique on the fishery foods

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Koji; Yano, Yutaka; Oikawa, Hiroshi [National Research Inst. of Fisheries Science, Yokohama (Japan)

    2000-02-01

    When muscles and myofibril are irradiated by gamma ray, Mg-ATPase activity increased with increasing of dose, but EDTA-ATPase decreased. If dose is very large, Ca-ATPase activity increased. The effects of state of protein on these phenomena were investigated. The muscles, myofibril and myosin B of Tilapia nilotica were used as samples. Change of Ca-ATPase, Mg-ATPase and EDTA-ATPase activity of myosin B by gamma-ray irradiation was the same as myofibril and muscles, but myosin B showed high sensitivity and each ATPase activity was changed by low dose. Accordingly, these values were more difficult to apply to detection technique of irradiation than state of muscle and myofibril. Collagen is known to degenerate and coagulate by gamma-ray irradiation. However, amount of hot water soluble collagen was increased with increasing of dose. (S.Y.)

  13. Determination of vitamin B12 (cobalamine) absorption by means of a simple double-isotope technique

    International Nuclear Information System (INIS)

    Hippe, E.; Brynskov, J.; Gimsing, P.; Hjelt, K.

    1986-01-01

    The background, practical instruction and clinical results of a simplified method of determining the absorption of cobalamine (vitamin B 12 ) are presented. The simultaneous administration of 57 CO-CN-cobalamine, a non-absorbable marker ( 51 CrCl 3 ), and red carmine tablets enable quantitative assessments of the cobalamine absorption by collection of a small red feaces sample. In contrast to the classical Schilling-test, this vitamin B 12 absorption test (B 12 -ABS-test) or faeces-spot-test is, independent of fasting, flushing dose, renal function and diurnal urinary collection. This is documented in a series of clinical studies. The B 12 -ABS-test provides accurate and precise results compared to the reference method (whole-body-counting). The Schilling test, on the contrary, gives approximately 50% false low values in a reference group of elderly hospitalized patients. A modification of the B 12 -ABS-test, has been used to determine the cobalamine absorption in children, and a set of age-related reference intervals have been established, together with quantitative measurements of the cobalamine absorption in children with small bowel diseases. Based on several years of practical experience, we recommend replacement of the Schilling test by this simple double-isotope technique. (author)

  14. Radiation detection technique on the fishery foods

    International Nuclear Information System (INIS)

    Oikawa, Hiroshi; Satomi, Masataka; Nakamura, Koji; Yano, Yutaka

    1999-01-01

    Recently irradiation of fishery products such as sea bream, lobster etc has been spreading in South-east Asia. It is thus necessary to establish a detection technique for irradiated foods . This study aimed to investigate the effects of irradiation on the production of tyrosine isomers with relation to the status of food sample (frozen and cold-storage) and also the stabilities of the isomers in frozen foods after irradiation. Production of tyrosin isomers (meta-tyrosine, ortho-tyrosine) due to γ-ray irradiation (5 kGy) were observed in the muscles of frozen prawns as well as those at room temperature and the contents of these isomers after the irradiation was not different between the two states of the sample. The content increased depending on the radiation dose. The contents of these tyrosine isomers were not changed after storage at -20degC for 120 days. Therefore, it was thought that the tyrosine isomers were available as an effective indicator for detection of an irradiated food. (M.N.)

  15. Atmospheric Pre-Corrected Differential Absorption Techniques to Retrieve Columnar Water Vapor: Theory and Simulations

    Science.gov (United States)

    Borel, Christoph C.; Schlaepfer, Daniel

    1996-01-01

    Two different approaches exist to retrieve columnar water vapor from imaging spectrometer data: (1) Differential absorption techniques based on: (a) Narrow-Wide (N/W) ratio between overlapping spectrally wide and narrow channels; (b) Continuum Interpolated Band Ratio (CIBR) between a measurement channel and the weighted sum of two reference channels. (2) Non-linear fitting techniques which are based on spectral radiative transfer calculations. The advantage of the first approach is computational speed and of the second, improved retrieval accuracy. Our goal was to improve the accuracy of the first technique using physics based on radiative transfer. Using a modified version of the Duntley equation, we derived an "Atmospheric Pre-corrected Differential Absorption" (APDA) technique and described an iterative scheme to retrieve water vapor on a pixel-by-pixel basis. Next we compared both, the CIBR and the APDA using the Duntley equation for MODTRAN3 computed irradiances, transmissions and path radiance (using the DISORT option). This simulation showed that the CIBR is very sensitive to reflectance effects and that the APDA performs much better. An extensive data set was created with the radiative transfer code 6S over 379 different ground reflectance spectra. The calculated relative water vapor error was reduced significantly for the APDA. The APDA technique had about 8% (vs. over 35% for the CIBR) of the 379 spectra with a relative water vapor error of greater than +5%. The APDA has been applied to 1991 and 1995 AVIRIS scenes which visually demonstrate the improvement over the CIBR technique.

  16. An Insight Into the Two Costing Technique: Absorption Costing and Marginal Costing

    Directory of Open Access Journals (Sweden)

    Mariam Nawaz

    2013-02-01

    Full Text Available This paper will investigate the controversy that is innate between the two costing techniques; Absorption Costing and Marginal Costing and would throw light on which costing technique better serves its purpose in helping management for decision making process and if Marginal Costing technique is concluded as better technique then why it should not be used for external reporting purpose. This paper will only crystallize and highlight the issues descriptively and will not resolve the issues that are inherent between the two costing techniques. The unique thing about this paper is that it is in favor of treating fixed cost as product cost that is it is supporting the advocates of Absorption Costing Technique but it is against to consider profit as a function of production rather it believes that profit should only be considered as function of sales for stock valuation and to help management in decision making process that is, regarding this point it is supporting advocates of Marginal Costing.

  17. Study of the texture of porous solids using a technique of γ ray absorption

    International Nuclear Information System (INIS)

    Ortega, M.

    1967-01-01

    A technique, which enables us to measure locally total porosity, open porosity and pore size distribution is developed. The total porosity is calculated from the bulk density. A gamma absorption gauge is set up fitted with a Cs137 source. This enables the determination of the density by layers of carbonaceous samples in a practically automatic way. By taking adequate precautions it is possible to obtain the density with a maximum error Δρ ≤ 0,005 g/cm 3 . The open porosity is evaluated by the absorption method after impregnation with bromoform. A new mercury porosimeter is developed using the absorption probe for the measurement of mercury infiltrated into the porous sample. Due to the localized character of exploration by this technique, the variations of porous texture in a heterogeneous sample can be studied. Used as a classical porosimeter, in the case of homogeneous samples, this apparatus is capable of exploring the equivalent diameters of pores between 500 μ and 0.14 μ with a maximum error ΔP ≤ 0.002. The possibility of exploration of heterogeneous samples, with the facility of determination of porosities due to macro-pores combined with the non-limiting character of the method in the field of high pressures differentiates this apparatus from all the porosimeters of former conception. Examples of utilization of this technique in the case of graphite-gas reactions are presented. (author) [fr

  18. Influence of soil and agricultural technique in metal absorption by vegetables

    International Nuclear Information System (INIS)

    Cunha, K. Dias da; Cazicava, J.; Coelho, M.; Dalia, K.

    2005-01-01

    The aim of this work is to verify the influence of soil and agricultural techniques in the metal absorption by the vegetables. Metal concentrations were evaluated in soil and vegetable samples from different regions and cultivated by different agricultural techniques. PIXE, 252 Cf-PDMS and Radiochemical techniques were applied. Si, Zr, Ce, Th and Pb, identified in soil samples, were not biologically available. Ga, Ge, As and Br, identified in tubercles, show that spray pesticides used on the vegetable leaves were absorbed by them. 232 Th and 238 U, presented in the soil, were not absorbed by the vegetables. Airborne particles from anthropogenic sources (CFn, VCn) were absorbed by the vegetables. Compounds from mineral sources, presented in soil, (V + , VCO 3 , HPO 4 , Cr + , CrOH + Mn + , FeH, Fe(OH) n ) and bioorganic compounds (N + , Ca(CN) n +, CnH + ) were identified in the vegetables. Metal absorbed by the vegetables is not dependent on metal concentration in soil. Different tubercles cultivated in the same soil show similar metal absorption. The exogenous contributions, such as the elements presented in water irrigation, pesticides, fertilizers and airborne particles deposited on leaves can be absorbed by the vegetables. Absorption by the roots depends on the chemical compound of the elements. Pesticide sprays and air pollution can cause more contamination in the vegetables than in the soil. The use of this methodology allows the identification of possible sources of metals in soils and in vegetables and metal speciation. (author)

  19. Analysis of relaxing laser-induced plasmas by absorption spectroscopy: Toward a new quantitative diagnostic technique

    International Nuclear Information System (INIS)

    Ribiere, M.; Cheron, B.G.

    2010-01-01

    Broad-band near UV absorption spectroscopy was used to analyze atmospheric laser-induced plasmas formed on metallic and refractory targets. When the common emission spectroscopy only provides the density of the radiating atomic excited states, the technique reported in this paper is able to achieve high spatial resolution in the measurement of absolute number densities in expanding laser-induced plasmas. The reliability and the versatility of this technique, which is based on the comparison between results of the numerical integration of the radiative transfer equation and experimental spectra, were tested on different targets. The evolutions in time and space of the absolute population of the plasma species originating from metallic alloys (Al-Mg and Cu-Ni) and refractory materials (C/SiC) were achieved over large time scales. Owing to its accuracy, this absorption technique (that we call 'LIPAS' for Laser Induced Plasma Absorption Spectroscopy) should bring a new and enhanced support to the validation of collisional-radiative models attempting to provide reliable evolutions of laser-induced plasmas.

  20. The technique of Cerenkov ring image detection

    International Nuclear Information System (INIS)

    Langerveld, D.

    1990-01-01

    Charged particles with an energy between 2 GeV and 25 GeV can be identified in the DELPHI barrel RICH detector by using the technique of Cerenkov ring image detection. The method of identification is based on a determination of the Cerenkov angle by measuring the positions of the emitted Cerenkov photons to high precision in a photon detector. The resolution in the photon that can be obtained depends mainly on the chromatic dispersion in the radiators and on the resolution in the photon detector is used in the barrel RICH in combination with two radiators. The photon detector consists of 48 drift tubes, constructed from quarz plates, each equipped with a wire chamber at the end. The drift gas with which the tubes are filled contains a small admixture of TMAE vapour from which the Cerenkov photons can liberate photoelectrons. It is shown in this thesis that an efficient photon detection and an accurate localization of the photon conversion points is possible. The spatial resolution of the photon detector is determind by the resolution of the wire chambe, the accuracy of the drift measurement, the distortions in the paths of the drifting electrons. The resolution of the wire chamber has been measured to be 0.8 mm in the x- and 1.7 mm in the y-coordinate. The error in the z-coordinate introduced by the drift time measurement is 0.2 mm. The distortions in the paths of the drifting electrons have been measured both in the x and y-direction. The longitudinal and transverse diffusion coefficients have been measured as a function of the field strength for two different drift gas mixtures. (author). 96 refs.; 61 figs.; 11 tabs

  1. Coal thickness gauge using RRAS techniques, part 1. [radiofrequency resonance absorption

    Science.gov (United States)

    Rollwitz, W. L.; King, J. D.

    1978-01-01

    A noncontacting sensor having a measurement range of 0 to 6 in or more, and with an accuracy of 0.5 in or better is needed to control the machinery used in modern coal mining so that the thickness of the coal layer remaining over the rock is maintained within selected bounds. The feasibility of using the radiofrequency resonance absorption (RRAS) techniques of electron magnetic resonance (EMR) and nuclear magnetic resonance (NMR) as the basis of a coal thickness gauge is discussed. The EMR technique was found, by analysis and experiments, to be well suited for this application.

  2. Fracture detection using subsurface electromagnetic techniques

    International Nuclear Information System (INIS)

    Zhou, Q.; Becker, A.; Goldstein, N.E.; Morrison, H.F.; Lee, K.H.

    1987-01-01

    Audio frequency subsurface electromagnetic (EM) techniques using cross-hole and in-hole arrays for fracture detection are evaluated numerically. The fracture zone is represented by a thin rectangular conductor with finite dimensions, embedded in a conductive host rock. Because of its practical advantages, the EM source considered in this study is a grounded vertical electrical dipole (G.V.E.D.) placed in a vertical bore hole. Three source-receiver configurations are considered. The first is the cross-hole configuration with the source and receiver moving parallel to each other in separate holes. The second configuration is a fixed source in one hole and a moving receiver in the other. Finally, the author also treat the case of a tandem source and receiver at fixed separation traversing a single hole. In all cases the conductive fracture zone is not intersected by either hole. Comparisons between the grounded electric dipole and the vertical magnetic dipole indicate clear advantages for the former

  3. Direct progeny detection techniques and random epidemiology

    International Nuclear Information System (INIS)

    Mayya, Y.S.; Mishra, Rosaline; Sapra, B.K.

    2015-01-01

    Over the past 40 years, there has been considerable progress in the measurements methods and their application to the estimates of risks due to radon among general populations. The previous decade saw major development in this regard. It was the direct estimate of indoor radon risk from epidemiological studies in Europe and North America. These were important findings that demonstrated the presence of lung cancer risks at residential radon levels supplementing the generally used risks estimates at high exposures obtained from uranium miner's data. The residential radon epidemiological studies largely used radon concentration as a measure of exposure. The exposure to decay products, which are primarily the dose givers, are assumed to be proportional to the measured gas concentrations. Also, the presence of thoron was neglected in these studies. Although several corrections have appeared to these assessments, the question of variability of actual decay product exposures has largely remained unaddressed. In order to circumvent this limitation, passive techniques were developed to estimate the decay product concentrations directly using deposition monitors. These are based on detecting the alpha particles from decay products deposited on an absorber mounted LR-115 detectors. Known as Direct radon, and Thoron Progeny sensors (DRPS/DTPS), these have been further refined to separate fine fraction from the coarse fraction by wire-mesh capping techniques. Large number environmental calibration exercises and field data generation has been carried out on the progeny concentrations in Indian and some European environments. The development of progeny sensors offers a new tool for future epidemiology. Since in the Indian context, there exist no radon related epidemiological estimates of risk, it is time one conducts large scale studies to seek possible correlations between DRPS/DTPS data and lung cancer risks. While epidemiological studies in High background radiation areas

  4. A cement channel-detection technique using the pulsed-neutron log

    International Nuclear Information System (INIS)

    Myers, G.D.

    1991-01-01

    A channel-detection technique has been developed using boron solutions and pulsed-neutron logging (PNL) tools. This technique relies on the extremely high-neutron-absorption cross section that boron exhibits relative to other common elements, including chlorine. The PNL tool is used to detect movement of a boron solution in a log-inject-log procedure. The technique has identified channels in such difficult applications as logging through two strings of pipe and in highly deviated wellbores. Logging procedures are simple and cement channels can be readily identified. The boron solutions are relatively inexpensive, safe to handle, and nonradioactive. Additional PNL information for reservoir performance evaluation is collected simultaneously during channel-detection logging. This paper describes the theory, development, field application, and limitations of this channel-detection logging technique

  5. Measurements of K shell absorption jump factors and jump ratios using EDXRF technique

    Science.gov (United States)

    Kacal, Mustafa Recep; Han, İbrahim; Akman, Ferdi

    2015-04-01

    In the present work, the K-shell absorption jump factors and jump ratios for 30 elements between Ti ( Z = 22) and Er ( Z = 68) were measured by energy dispersive X-ray fluorescence (EDXRF) technique. The jump factors and jump ratios for these elements were determined by measuring the K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to- Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using an Am-241 radioactive point source and a Si (Li) detector in direct excitation and transmission experimental geometry. The results for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature.

  6. Force-detected nanoscale absorption spectroscopy in water at room temperature using an optical trap

    Science.gov (United States)

    Parobek, Alexander; Black, Jacob W.; Kamenetska, Maria; Ganim, Ziad

    2018-04-01

    Measuring absorption spectra of single molecules presents a fundamental challenge for standard transmission-based instruments because of the inherently low signal relative to the large background of the excitation source. Here we demonstrate a new approach for performing absorption spectroscopy in solution using a force measurement to read out optical excitation at the nanoscale. The photoinduced force between model chromophores and an optically trapped gold nanoshell has been measured in water at room temperature. This photoinduced force is characterized as a function of wavelength to yield the force spectrum, which is shown to be correlated to the absorption spectrum for four model systems. The instrument constructed for these measurements combines an optical tweezer with frequency domain absorption spectroscopy over the 400-800 nm range. These measurements provide proof-of-principle experiments for force-detected nanoscale spectroscopies that operate under ambient chemical conditions.

  7. Gamma Ray Absorption Technique For Scannig Process Column In Up-IV Pertamina Cilacap

    International Nuclear Information System (INIS)

    Santoso, Sigit Budi; Kushartono; Bisana; Mulyanto, Eko; Adi, Soecipto

    2000-01-01

    A demonstration using gamma ray absorption technique was carried out to diagnose malfunction such as tray missing, flooding, and weeping occurred in 2 3C-5 Extraction Vacuum Flash Strip Tower . The scan was conducted from the bottom until the top of the orientation of the director-source are (122 o -308 o ) dan (122 o - 270 o ). The results indicate that the tray number 1 and 3 were missing while weeping occurred in the space between tray 4,5,6,and 7. The results show that this technique can be used to diagnose malfunction occurred in the column on-line so it can help maintenance personnel in planning, the time scheduled and spare part for shutdown. Beside of that this technique can be developed to help column personnel's in adjusting the operation parameter to achieve optimum operation

  8. Atmospheric pre-corrected differential absorption techniques to retrieve columnar water vapor: Theory and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Borel, C.C.; Schlaepfer, D.

    1996-03-01

    Two different approaches exist to retrieve columnar water vapor from imaging spectrometer data: (1) Differential absorption techniques based on: (a) Narrow-Wide (N/W) ratio between overlapping spectrally wide and narrow channels (b) Continuum Interpolated Band Ratio (CIBR) between a measurement channel and the weighted sum of two reference channels; and (2) Non-linear fitting techniques which are based on spectral radiative transfer calculations. The advantage of the first approach is computational speed and of the second, improved retrieval accuracy. Our goal was to improve the accuracy of the first technique using physics based on radiative transfer. Using a modified version of the Duntley equation, we derived an {open_quote}Atmospheric Pre-corrected Differential Absorption{close_quote} (APDA) technique and described an iterative scheme to retrieve water vapor on a pixel-by-pixel basis. Next we compared both, the CIBR and the APDA using the Duntley equation for MODTRAN3 computed irradiances, transmissions and path radiance (using the DISORT option). This simulation showed that the CIBR is very sensitive to reflectance effects and that the APDA performs much better. An extensive data set was created with the radiative transfer code 6S over 379 different ground reflectance spectra. The calculated relative water vapor error was reduced significantly for the APDA. The APDA technique had about 8% (vs. over 35% for the CIBR) of the 379 spectra with a relative water vapor error of greater than {+-}5%. The APDA has been applied to 1991 and 1995 AVIRIS scenes which visually demonstrate the improvement over the CIBR technique.

  9. Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

    Science.gov (United States)

    Wang, Yanru; Li, Bincheng

    2012-11-01

    The laser calorimetry (LCA) technique is used to determine simultaneously the absorptances and thermal diffusivities of optical components. An accurate temperature model, in which both the finite thermal conductivity and the finite sample size are taken into account, is employed to fit the experimental temperature data measured with an LCA apparatus for a precise determination of the absorptance and thermal diffusivity via a multiparameter fitting procedure. The uniqueness issue of the multiparameter fitting is discussed in detail. Experimentally, highly reflective (HR) samples prepared with electron-beam evaporation on different substrates (BK7, fused silica, and Ge) are measured with LCA. For the HR-coated sample on a fused silica substrate, the absorptance is determined to be 15.4 ppm, which is close to the value of 17.6 ppm, determined with a simplified temperature model recommended in the international standard ISO11551. The thermal diffusivity is simultaneously determined via multiparameter fitting to be approximately 6.63 × 10-7 m2 · s-1 with a corresponding square variance of 4.8 × 10-4. The fitted thermal diffusivity is in reasonably good agreement with the literature value (7.5 × 10-7 m2 · s -1). Good agreement is also obtained for samples with BK7 and Ge substrates.

  10. A New Generic Taxonomy on Hybrid Malware Detection Technique

    OpenAIRE

    Robiah, Y.; Rahayu, S. Siti; Zaki, M. Mohd; Shahrin, S.; Faizal, M. A.; Marliza, R.

    2009-01-01

    Malware is a type of malicious program that replicate from host machine and propagate through network. It has been considered as one type of computer attack and intrusion that can do a variety of malicious activity on a computer. This paper addresses the current trend of malware detection techniques and identifies the significant criteria in each technique to improve malware detection in Intrusion Detection System (IDS). Several existing techniques are analyzing from 48 various researches and...

  11. Technique detection software for Sparse Matrices

    Directory of Open Access Journals (Sweden)

    KHAN Muhammad Taimoor

    2009-12-01

    Full Text Available Sparse storage formats are techniques for storing and processing the sparse matrix data efficiently. The performance of these storage formats depend upon the distribution of non-zeros, within the matrix in different dimensions. In order to have better results we need a technique that suits best the organization of data in a particular matrix. So the decision of selecting a better technique is the main step towards improving the system's results otherwise the efficiency can be decreased. The purpose of this research is to help identify the best storage format in case of reduced storage size and high processing efficiency for a sparse matrix.

  12. Detection of the Galactic Warm Neutral Medium in HI 21cm absorption

    Science.gov (United States)

    Patra, Narendra Nath; Kanekar, Nissim; Chengalur, Jayaram N.; Roy, Nirupam

    2018-05-01

    We report a deep Giant Metrewave Radio Telescope (GMRT) search for Galactic HI 21cm absorption towards the quasar B0438-436, yielding the detection of wide, weak HI 21cm absorption, with a velocity-integrated HI 21cm optical depth of 0.0188 ± 0.0036 km s-1. Comparing this with the HI column density measured in the Parkes Galactic All-Sky Survey gives a column density-weighted harmonic mean spin temperature of 3760 ± 365 K, one of the highest measured in the Galaxy. This is consistent with most of the HI along the sightline arising in the stable warm neutral medium (WNM). The low peak HI 21cm optical depth towards B0438-436 implies negligible self-absorption, allowing a multi-Gaussian joint decomposition of the HI 21cm absorption and emission spectra. This yields a gas kinetic temperature of T_k ≤ (4910 ± 1900) K, and a spin temperature of T_s = (1000 ± 345) K for the gas that gives rise to the HI 21cm absorption. Our data are consistent with the HI 21cm absorption arising from either the stable WNM, with T_s ≪ T_k, T_k ≈ 5000 K, and little penetration of the background Lyman-α radiation field into the neutral hydrogen, or from the unstable neutral medium, with T_s ≈ T_k ≈ 1000K.

  13. Corrections of residual fluorescence distortions for a glancing-emergence-angle x-ray-absorption technique

    International Nuclear Information System (INIS)

    Brewe, D.L.; Pease, D.M.; Budnick, J.I.

    1994-01-01

    Distortions appear in x-ray-absorption spectra obtained by monitoring the fluorescence from thick samples with concentrated absorbing species. The glancing-emergence-angle technique for obtaining spectra from this type of sample eliminates distortions from the measured spectra by monitoring the fluorescence leaving the sample at a small angle relative to the sample surface. This technique is limited by the small signal available from the inherently limited detector solid angle. In addition, no precise estimate of the required restriction on maximum emergent angle θ max has been available. We have calculated residual extended x-ray-absorption fine structure distortions as a function of θ max , and performed experimental tests of the calculations. These calculations provide a means to estimate the required detector geometry for negligible distortions, or alternatively, allow the use of a larger θ max , increasing the available signal, with the remaining residual distortions removed by application of the calculations. The calculations are also applicable to other detector geometries, and account for detectors subtending a large solid angle by an integration over the subtended angle. This represents an improvement over previous calculations. The application to more general detector configurations is also discussed

  14. Detection of ocean glint and ozone absorption using LCROSS Earth observations

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Tyler D. [NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035 (United States); Ennico, Kimberly [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Meadows, Victoria S.; Sparks, William; Schwieterman, Edward W. [NASA Astrobiology Institute' s Virtual Planetary Laboratory, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Bussey, D. Ben J. [NASA Ames Research Center, MS 17-1, Moffett Field, CA 94089, USA Now the NASA Solar System Exploration Research Virtual Institute. (United States); Breiner, Jonathan, E-mail: tyler.d.robinson@nasa.gov [Astronomy Department, University of Washington, Seattle, WA 98195 (United States)

    2014-06-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and mid-infrared full-disk images, and partial-disk spectra at 0.26-0.65 μm (λ/Δλ ∼ 500) and 1.17-2.48 μm (λ/Δλ ∼ 50). Spectra show strong absorption features due to water vapor and ozone, which is a biosignature gas. We perform a significant recalibration of the UV-visible spectra and provide the first comparison of high-resolution visible Earth spectra to the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model. We find good agreement with the observations, reproducing the absolute brightness and dynamic range at all wavelengths for all observation epochs, thus validating the model to within the ∼10% data calibration uncertainty. Data-model comparisons reveal a strong ocean glint signature in the crescent phase data set, which is well matched by our model predictions throughout the observed wavelength range. This provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths, where the glint signal is strongest. We examine the detection of the ozone 255 nm Hartley and 400-700 nm Chappuis bands. While the Hartley band is the strongest ozone feature in Earth's spectrum, false positives for its detection could exist. Finally, we discuss the implications of these findings for future exoplanet characterization missions.

  15. Detection of ocean glint and ozone absorption using LCROSS Earth observations

    International Nuclear Information System (INIS)

    Robinson, Tyler D.; Ennico, Kimberly; Meadows, Victoria S.; Sparks, William; Schwieterman, Edward W.; Bussey, D. Ben J.; Breiner, Jonathan

    2014-01-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and mid-infrared full-disk images, and partial-disk spectra at 0.26-0.65 μm (λ/Δλ ∼ 500) and 1.17-2.48 μm (λ/Δλ ∼ 50). Spectra show strong absorption features due to water vapor and ozone, which is a biosignature gas. We perform a significant recalibration of the UV-visible spectra and provide the first comparison of high-resolution visible Earth spectra to the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model. We find good agreement with the observations, reproducing the absolute brightness and dynamic range at all wavelengths for all observation epochs, thus validating the model to within the ∼10% data calibration uncertainty. Data-model comparisons reveal a strong ocean glint signature in the crescent phase data set, which is well matched by our model predictions throughout the observed wavelength range. This provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths, where the glint signal is strongest. We examine the detection of the ozone 255 nm Hartley and 400-700 nm Chappuis bands. While the Hartley band is the strongest ozone feature in Earth's spectrum, false positives for its detection could exist. Finally, we discuss the implications of these findings for future exoplanet characterization missions.

  16. 'Intelligent' triggering methodology for improved detectability of wavelength modulation diode laser absorption spectrometry applied to window-equipped graphite furnaces

    International Nuclear Information System (INIS)

    Gustafsson, Joergen; Axner, Ove

    2003-01-01

    The wavelength modulation-diode laser absorption spectrometry (WM-DLAS) technique experiences a limited detectability when window-equipped sample compartments are used because of multiple reflections between components in the optical system (so-called etalon effects). The problem is particularly severe when the technique is used with a window-equipped graphite furnace (GF) as atomizer since the heating of the furnace induces drifts of the thickness of the windows and thereby also of the background signals. This paper presents a new detection methodology for WM-DLAS applied to a window-equipped GF in which the influence of the background signals from the windows is significantly reduced. The new technique, which is based upon a finding that the WM-DLAS background signals from a window-equipped GF are reproducible over a considerable period of time, consists of a novel 'intelligent' triggering procedure in which the GF is triggered at a user-chosen 'position' in the reproducible drift-cycle of the WM-DLAS background signal. The new methodology makes also use of 'higher-than-normal' detection harmonics, i.e. 4f or 6f, since these previously have shown to have a higher signal-to-background ratio than 2f-detection when the background signals originates from thin etalons. The results show that this new combined background-drift-reducing methodology improves the limit of detection of the WM-DLAS technique used with a window-equipped GF by several orders of magnitude as compared to ordinary 2f-detection, resulting in a limit of detection for a window-equipped GF that is similar to that of an open GF

  17. Determination of mercury in an assortment of dietary supplements using an inexpensive combustion atomic absorption spectrometry technique.

    Science.gov (United States)

    Levine, Keith E; Levine, Michael A; Weber, Frank X; Hu, Ye; Perlmutter, Jason; Grohse, Peter M

    2005-01-01

    The concentrations of mercury in forty, commercially available dietary supplements, were determined using a new, inexpensive analysis technique. The method involves thermal decomposition, amalgamation, and detection of mercury by atomic absorption spectrometry with an analysis time of approximately six minutes per sample. The primary cost savings from this approach is that labor-intensive sample digestion is not required prior to analysis, further automating the analytical procedure. As a result, manufacturers and regulatory agencies concerned with monitoring lot-to-lot product quality may find this approach an attractive alternative to the more classical acid-decomposition, cold vapor atomic absorption methodology. Dietary supplement samples analyzed included astragalus, calcium, chromium picolinate, echinacea, ephedra, fish oil, ginger, ginkgo biloba, ginseng, goldenseal, guggul, senna, St John's wort, and yohimbe products. Quality control samples analyzed with the dietary supplements indicated a high level of method accuracy and precision. Ten replicate preparations of a standard reference material (NIST 1573a, tomato leaves) were analyzed, and the average mercury recovery was 109% (2.0% RSD). The method quantitation limit was 0.3 ng, which corresponded to 1.5 ng/g sample. The highest found mercury concentration (123 ng/g) was measured in a concentrated salmon oil sample. When taken as directed by an adult, this product would result in an approximate mercury ingestion of 7 mug per week.

  18. 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.

  19. Technique for detecting liquid metal leaks

    International Nuclear Information System (INIS)

    Bauerle, J.E.

    1979-01-01

    In a system employing flowing liquid metal as a heat transfer medium in contact with tubular members containing a working fluid, i.e., steam, liquid metal leaks through the wall of the tubular member are detected by dislodging the liquid metal compounds forming in the tubular member at the leak locations and subsequently transporting the dislodged compound in the form of an aerosol to a detector responsive to the liquid metal compound. In the application to a sodium cooled tubular member, the detector would consist of a sodium responsive device, such as a sodium ion detector

  20. Fission Detection Using the Associated Particle Technique

    International Nuclear Information System (INIS)

    R.P. Keegan; J.P. Hurley; J.R. Tinsley; R. Trainham; S.C. Wilde

    2008-01-01

    A beam of tagged 14 MeV neutrons from the deuterium-tritium (DT) reaction is used to induce fission in a target composed of depleted uranium. The generator yield is 10 7 neutrons/second radiated into a 4 x 4 in. NaI detectors are used for gamma-ray detection. The fission process is known to produce multiple gamma-rays and neutrons. Triple coincidences (α-γ-γ) are measured as a function of neutron flight time up to 90 ns after fission, where the α-particle arises from the DT reaction. A sudden increase in the triple coincidence rate at the location of the material is used to localize and detect fission in the interrogated target. Comparisons are made with experiment runs where lead, tungsten, and iron were used as target materials. The triple coincidence response profile from depleted uranium is noted to be different to those observed from the other target materials. The response from interrogation targets composed of fissile material is anticipated to be even more unique than that observed from depleted uranium

  1. Molecular detection with terahertz waves based on absorption-induced transparency metamaterials

    Science.gov (United States)

    G. Rodrigo, Sergio; Martín-Moreno, L.

    2016-10-01

    A system for the detection of spectral signatures of chemical compounds at the Terahertz regime is presented. The system consists on a holey metal film whereby the presence of a given substance provokes the appearance of spectral features in transmission and reflection induced by the molecular specimen. These induced effects can be regarded as an extraordinary optical transmission phenomenon called absorption-induced transparency (AIT). The phenomenon consist precisely in the appearance of peaks in transmission and dips in reflection after sputtering of a chemical compound onto an initially opaque holey metal film. The spectral signatures due to AIT occur unexpectedly close to the absorption energies of the molecules. The presence of a target, a chemical compound, would be thus revealed as a strong drop in reflectivity measurements. We theoretically predict the AIT based system would serve to detect amounts of hydrocyanic acid (HCN) at low rate concentrations.

  2. Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane—Breath Biomarkers of Serious Diseases

    Science.gov (United States)

    Wojtas, Jacek

    2015-01-01

    The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases. PMID:26091398

  3. Vitamin A equivalency and apparent absorption of ß-carotene in ileostomy subjects using a dual-isotope dilution technique

    NARCIS (Netherlands)

    Bouwman, C.A.; Naber, T.H.J.; Breemen, van R.B.; Zhu, D.; Dicke, H.; Siebelink, E.; Hulshof, P.J.M.; Russel, F.G.M.; Schaafsma, G.; West, C.E.

    2010-01-01

    The objective was to quantify the vitamin A equivalency of ß-carotene in two diets using a dual-isotope dilution technique and the apparent ß-carotene absorption as measured by the oral–faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled,

  4. Vitamin A equivalency and apparent absorption of beta-carotene in ileostomy subjects using a dual-isotope dilution technique.

    NARCIS (Netherlands)

    Loo-Bouwman, C.A. Van; Naber, T.H.; Breemen, R.B. van; Zhu, D.; Dicke, H.; Siebelink, E.; Hulshof, P.J.; Russel, F.G.M.; Schaafsma, G.; West, C.E.

    2010-01-01

    The objective was to quantify the vitamin A equivalency of beta-carotene in two diets using a dual-isotope dilution technique and the apparent beta-carotene absorption as measured by the oral-faecal balance technique. Seventeen healthy adults with an ileostomy completed the 4-week diet-controlled,

  5. Detection limits for radioanalytical counting techniques

    International Nuclear Information System (INIS)

    Hartwell, J.K.

    1975-06-01

    In low-level radioanalysis it is usually necessary to test the sample net counts against some ''Critical Level'' in order to determine if a given result indicates detection. This is an interpretive review of the work by Nicholson (1963), Currie (1968) and Gilbert (1974). Nicholson's evaluation of three different computational formulas for estimation of the ''Critical Level'' is discussed. The details of Nicholson's evaluation are presented along with a basic discussion of the testing procedures used. Recommendations are presented for calculation of confidence intervals, for reporting of analytical results, and for extension of the derived formula to more complex cases such as multiple background counts, multiple use of a single background count, and gamma spectrometric analysis

  6. Pollution detection using the spectral fluorescent signatures (SFS technique

    Directory of Open Access Journals (Sweden)

    Mª Del Carmen Martín

    2014-06-01

    Full Text Available This work has been developed in the Applied Physics Department at the University of Vigo within the line of research based on the treatment of the degraded water by pollutants through the use of microalgae, reducing the emissions of greenhouse gases through the absorption of CO2 in the process and the reuse of biomass as biofuel. Remote sensing techniques have contributed to a great extent to the development of oil pollution monitoring systems. However, the available detection methods, mainly designed for spaceborne and airborne long distance inspection, are too expensive and complex to be used in an operational way by relatively unskilled personnel. In the framework of DEOSOM project (European AMPERA project, an innovative water monitoring method was proposed, in two steps: early oil spill detection using a portable shipborne laser-induced fluorescence LIDAR (LIF/LIDAR, and analysis of suspicious water samples in laboratory using the Spectral Fluorescent Signature (SFS technique. This work is focused on the second technique. This system aims to optimize the production of microalgae for biofuel and contaminant cleaning applications and was developed and tested in photo-bioreactors in the University of Vigo within the EnerBioAlgae project (SUDOE. In this project, the SFS technique was used as a diagnostic tool employing the fluorescence analyzer INSTANT-SCREENER M53UVC. The Spectral Fluorescence Signature technique (SFS is based on compounds fluorescence properties. The fluorescence intensity of a sample is measured at different excitation and emission wavelengths to produce a 3-dimensional fluorescence matrix, which can also be presented as a 2-dimensional color image where the color shows the intensity of the fluorescence. These matrices offer qualitative and quantitative information, since they can be useful for the identification of different substances from their characteristic excitation and emission spectra of fluorescence. They also

  7. Novel gas-based detection techniques

    International Nuclear Information System (INIS)

    Graaf, Harry van der

    2009-01-01

    This year we celebrate the 100th birthday of gaseous detectors: Hans Geiger operated the first gas-filled counter in Manchester in 1908. The thin wires, essential for obtaining gas amplification, have been replaced by Micro Pattern Gas Detectors (MPGDs): Micromegas (1995) and GEM (1996). In the GridPix detector, each of the grid holes of a MPGD is equipped with its own electronic readout channel in the form of an active pixel in suitable pixel CMOS chips. By means of MEMS technology, the grid has been integrated with the chip, forming a monolithic readout device for gas volumes. By applying a protection layer made of hydrogenated amorphous silicon, the chips can be made spark proof. New protection layers have been made of silicon nitride. The use of gas as detection material for trackers is compared to Si, and the issue of chamber aging is addressed. New developments are set out: the development of Micro Channel Plates, integrated on pixel chips, the development of electron emission foil, and the realization of TimePix-2: a general-purpose pixel chip with time and amplitude measurement, per pixel, of charge signals.

  8. Time reversal technique for gas leakage detection.

    Science.gov (United States)

    Maksimov, A O; Polovinka, Yu A

    2015-04-01

    The acoustic remote sensing of subsea gas leakage traditionally uses sonars as active acoustic sensors and hydrophones picking up the sound generated by a leak as passive sensors. When gas leaks occur underwater, bubbles are produced and emit sound at frequencies intimately related to their sizes. The experimental implementation of an acoustic time-reversal mirror (TRM) is now well established in underwater acoustics. In the basic TRM experiment, a probe source emits a pulse that is received on an array of sensors, time reversed, and re-emitted. After time reversal, the resulting field focuses back at the probe position. In this study, a method for enhancing operation of the passive receiving system has been proposed by using it in the regime of TRM. Two factors, the local character of the acoustic emission signal caused by the leakage and a resonant nature of the bubble radiation at their birth, make particularly effective scattering with the conjugate wave (CW). Analytical calculations are performed for the scattering of CW wave on a single bubble when CW is formed by bubble birthing wail received on an array, time reversed, and re-emitted. The quality of leakage detection depends on the spatio-temporal distribution of ambient noise.

  9. Protection without detection: a threat mitigation technique

    Science.gov (United States)

    White, Joshua; McCoy, Joseph R.; Ratazzi, Paul

    2012-05-01

    Networking systems and individual applications have traditionally been defended using signature-based tools that protect the perimeter, many times to the detriment of service, performance, and information flow. These tools require knowledge of both the system on which they run and the attack they are preventing. As such, by their very definition, they only account for what is known to be malicious and ignore the unknown. The unknown, or zero day threat, can occur when defenses have yet to be immunized via a signature or other identifier of the threat. In environments where execution of the mission is paramount, the networks and applications must perform their function of information delivery without endangering the enterprise or losing the salient information, even when facing zero day threats. In this paper we, describe a new defensive strategy that provides a means to more deliberately balance the oft mutually exclusive aspects of protection and availability. We call this new strategy Protection without Detection, since it focuses on network protection without sacrificing information availability. The current instantiation analyzes the data stream in real time as it passes through an in-line device. Critical files are recognized, and mission-specific trusted templates are applied as they are forwarded to their destination. The end result is a system which eliminates the opportunity for propagation of malicious or unnecessary payloads via the various containers that are inherent in the definition of standard file types. In some cases, this method sacrifices features or functionality that is typically inherent in these files. However, with the flexibility of the template approach, inclusion or exclusion of these features becomes a deliberate choice of the mission owners, based on their needs and amount of acceptable risk. The paper concludes with a discussion of future extensions and applications.

  10. Laser induced fluorescence technique for detecting organic matter in East China Sea

    Science.gov (United States)

    Chen, Peng; Wang, Tianyu; Pan, Delu; Huang, Haiqing

    2017-10-01

    A laser induced fluorescence (LIF) technique for fast diagnosing chromophoric dissolved organic matter (CDOM) in water is discussed. We have developed a new field-portable laser fluorometer for rapid fluorescence measurements. In addtion, the fluorescence spectral characteristics of fluorescent constituents (e.g., CDOM, chlorophyll-a) were analyzed with a spectral deconvolution method of bi-Gaussian peak function. In situ measurements by the LIF technique compared well with values measured by conventional spectrophotometer method in laboratory. A significant correlation (R2 = 0.93) was observed between fluorescence by the technique and absorption by laboratory spectrophotometer. Influence of temperature variation on LIF measurement was investigated in lab and a temperature coefficient was deduced for fluorescence correction. Distributions of CDOM fluorescence measured using this technique in the East China Sea coast were presented. The in situ result demonstrated the utility of the LIF technique for rapid detecting dissolved organic matter.

  11. Speciation of water soluble iron in size segregated airborne particulate matter using LED based liquid waveguide with a novel dispersive absorption spectroscopic measurement technique

    International Nuclear Information System (INIS)

    Chan, K.L.; Jiang, S.Y.N.; Ning, Z.

    2016-01-01

    In this study, we present the development and evaluation of a dispersive absorption spectroscopic technique for trace level soluble ferrous detection. The technique makes use of the broadband absorption spectra of the ferrous-ferrozine complex with a novel spectral fitting algorithm to determine soluble ferrous concentrations in samples and achieves much improved measurement precision compared to conventional methods. The developed method was evaluated by both model simulations and experimental investigations. The results demonstrated the robustness of the method against the spectral fluctuation, wavelength drift and electronic noise, while achieving excellent linearity (R 2  > 0.999) and low detection limit (0.06 μg L −1 ) for soluble ferrous detection. The developed method was also used for the speciation of soluble iron in size segregated atmospheric aerosols. The measurement was carried out during Spring and Summer in typical urban environment in Hong Kong. The measured total iron concentrations are in good agreement compared to conventional Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES) measurements. Investigation on ambient particulate matter samples shows the size dependent characteristic of iron speciation in the atmosphere with a more active role of fine particles in transforming between ferrous and ferric. The method demonstrated in this study provides a cost and time effective approach for the speciation of iron in ambient aerosols. - Highlights: • Dispersive absorption spectroscopic technique for trace level ferrous detection. • The spectral fitting retrieval improved the measurement precision and stability. • Extremely low detection limit was achieved for aqueous ferrous measurement. • Iron in size segregated particulate matters shows seasonal characteristic. • More active role of iron was found in fine particles compared to coarse particles.

  12. Speciation of water soluble iron in size segregated airborne particulate matter using LED based liquid waveguide with a novel dispersive absorption spectroscopic measurement technique

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K.L. [Meteorological Institute, Ludwig Maximilian University of Munich, Munich (Germany); School of Energy and Environment, City University of Hong Kong (Hong Kong); Jiang, S.Y.N. [School of Energy and Environment, City University of Hong Kong (Hong Kong); Ning, Z., E-mail: zhining@cityu.edu.hk [School of Energy and Environment, City University of Hong Kong (Hong Kong); Guy Carpenter Climate Change Centre, City University of Hong Kong (Hong Kong)

    2016-03-31

    In this study, we present the development and evaluation of a dispersive absorption spectroscopic technique for trace level soluble ferrous detection. The technique makes use of the broadband absorption spectra of the ferrous-ferrozine complex with a novel spectral fitting algorithm to determine soluble ferrous concentrations in samples and achieves much improved measurement precision compared to conventional methods. The developed method was evaluated by both model simulations and experimental investigations. The results demonstrated the robustness of the method against the spectral fluctuation, wavelength drift and electronic noise, while achieving excellent linearity (R{sup 2} > 0.999) and low detection limit (0.06 μg L{sup −1}) for soluble ferrous detection. The developed method was also used for the speciation of soluble iron in size segregated atmospheric aerosols. The measurement was carried out during Spring and Summer in typical urban environment in Hong Kong. The measured total iron concentrations are in good agreement compared to conventional Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES) measurements. Investigation on ambient particulate matter samples shows the size dependent characteristic of iron speciation in the atmosphere with a more active role of fine particles in transforming between ferrous and ferric. The method demonstrated in this study provides a cost and time effective approach for the speciation of iron in ambient aerosols. - Highlights: • Dispersive absorption spectroscopic technique for trace level ferrous detection. • The spectral fitting retrieval improved the measurement precision and stability. • Extremely low detection limit was achieved for aqueous ferrous measurement. • Iron in size segregated particulate matters shows seasonal characteristic. • More active role of iron was found in fine particles compared to coarse particles.

  13. Techniques and problems in studying intestinal absorption with radioactive isotopes in children

    International Nuclear Information System (INIS)

    James, W.P.T.; Waterlow, J.C.

    1976-01-01

    Radioactive isotopes give substantial promise for assisting the study of gastrointestinal absorption in children in that they allow reduction or elimination of the collection of blood, urine and faeces specimens. These operations are particularly difficult and unreliable in infants, on whom greatest interest in paediatric gastroenterology is centred in the tropics. Here intestinal malabsorption is most commonly associated with malnutrition, lactose intolerance, gastroenteritis, parasitic infestation and iron-deficiency anaemia. Two general techniques that have been employed are whole-body counting and analyses of 14 CO 2 exhaled in the breath after the feeding of 14 C-labelled nutrients. The former is advantageous if radionuclides suitable for the test at hand exist; the latter may be hard to interpret because of problems in the distribution and metabolism of the nutrient and intermediary products. Proper selection and understanding of the tests is particularly important in paediatric work, where the use of radioactive tracer techniques is unacceptable merely for the convenience of the investigator. (author)

  14. Evaluation of radiographic imaging techniques in lung nodule detection

    International Nuclear Information System (INIS)

    Ho, J.T.; Kruger, R.A.

    1989-01-01

    Dual-energy radiography appears to be the most effective technique to address bone superposition that compromises conventional chest radiography. A dual-energy, single-exposure, film-based technique was compared with a dual-energy, dual-exposure technique and conventional chest radiography in a simulated lung nodule detection study. Observers detected more nodules on images produced by dual-energy techniques than on images produced by conventional chest radiography. The difference between dual-energy and conventional chest radiography is statistically significant and the difference between dual-energy, dual-exposure and single-exposure techniques is statistically insignificant. The single-exposure technique has the potential to replace the dual-exposure technique in future clinical application

  15. Nondestructive damage detection and evaluation technique for seismically damaged structures

    Science.gov (United States)

    Adachi, Yukio; Unjoh, Shigeki; Kondoh, Masuo; Ohsumi, Michio

    1999-02-01

    The development of quantitative damage detection and evaluation technique, and damage detection technique for invisible damages of structures are required according to the lessons from the 1995 Hyogo-ken Nanbu earthquake. In this study, two quantitative damage sensing techniques for highway bridge structures are proposed. One method is to measure the change of vibration characteristics of the bridge structure. According to the damage detection test for damaged bridge column by shaking table test, this method can successfully detect the vibration characteristic change caused by damage progress due to increment excitations. The other method is to use self-diagnosis intelligent materials. According to the reinforced concrete beam specimen test, the second method can detect the damage by rupture of intelligent sensors, such as optical fiber or carbon fiber reinforced plastic rod.

  16. Shapes of the $^{192,190}$Pb ground states from beta decay studies using the total absorption technique

    CERN Document Server

    Estevez Aguado, M.E.; Agramunt, J.; Rubio, B.; Tain, J.L.; Jordan, D.; Fraile, L.M.; Gelletly, W.; Frank, A.; Csatlos, M.; Csige, L.; Dombradi, Zs.; Krasznahorkay, A.; Nacher, E.; Sarriguren, P.; Borge, M.J.G.; Briz, J.A.; Tengblad, O.; Molina, F.; Moreno, O.; Kowalska, M.; Fedosseev, V.N.; Marsh, B.A.; Fedorov, D.V.; Molkanov, P.L.; Andreyev, A.N.; Seliverstov, M.D.; Burkard, K.; Huller, W.

    2015-01-01

    The beta decay of $^{192,190}$Pb has been studied using the total absorption technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the $^{192,190}$Pb isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects.

  17. Development of a real-time absorption method for detecting the mercaptan odorizing mixture of natural gas

    NARCIS (Netherlands)

    Kireev, SV; Petrov, NG; Podolyako, EM; Shnyrev, SL

    The absorption of mercaptan mixtures used for odorizing natural gas and mixtures of natural gas is experimentally studied in the spectral range 2.5-20 mu m. An absorption method for the real-time detection of the odorant concentration is proposed. The method is based on intensity measurements of the

  18. A Simple Ultrasonic Experiment Using a Phase Shift Detection Technique.

    Science.gov (United States)

    Yunus, W. Mahmood Mat; Ahmad, Maulana

    1996-01-01

    Describes a simple ultrasonic experiment that can be used to measure the purity of liquid samples by detecting variations in the velocity of sound. Uses a phase shift detection technique that incorporates the use of logic gates and a piezoelectric transducer. (JRH)

  19. Detection technique of targets for missile defense system

    Science.gov (United States)

    Guo, Hua-ling; Deng, Jia-hao; Cai, Ke-rong

    2009-11-01

    Ballistic missile defense system (BMDS) is a weapon system for intercepting enemy ballistic missiles. It includes ballistic-missile warning system, target discrimination system, anti-ballistic-missile guidance systems, and command-control communication system. Infrared imaging detection and laser imaging detection are widely used in BMDS for surveillance, target detection, target tracking, and target discrimination. Based on a comprehensive review of the application of target-detection techniques in the missile defense system, including infrared focal plane arrays (IRFPA), ground-based radar detection technology, 3-dimensional imaging laser radar with a photon counting avalanche photodiode (APD) arrays and microchip laser, this paper focuses on the infrared and laser imaging detection techniques in missile defense system, as well as the trends for their future development.

  20. Planetary Gearbox Fault Detection Using Vibration Separation Techniques

    Science.gov (United States)

    Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    Studies were performed to demonstrate the capability to detect planetary gear and bearing faults in helicopter main-rotor transmissions. The work supported the Operations Support and Sustainment (OSST) program with the U.S. Army Aviation Applied Technology Directorate (AATD) and Bell Helicopter Textron. Vibration data from the OH-58C planetary system were collected on a healthy transmission as well as with various seeded-fault components. Planetary fault detection algorithms were used with the collected data to evaluate fault detection effectiveness. Planet gear tooth cracks and spalls were detectable using the vibration separation techniques. Sun gear tooth cracks were not discernibly detectable from the vibration separation process. Sun gear tooth spall defects were detectable. Ring gear tooth cracks were only clearly detectable by accelerometers located near the crack location or directly across from the crack. Enveloping provided an effective method for planet bearing inner- and outer-race spalling fault detection.

  1. Signal processing techniques for sodium boiling noise detection

    International Nuclear Information System (INIS)

    1989-05-01

    At the Specialists' Meeting on Sodium Boiling Detection organized by the International Working Group on Fast Reactors (IWGFR) of the International Atomic Energy Agency at Chester in the United Kingdom in 1981 various methods of detecting sodium boiling were reported. But, it was not possible to make a comparative assessment of these methods because the signal condition in each experiment was different from others. That is why participants of this meeting recommended that a benchmark test should be carried out in order to evaluate and compare signal processing methods for boiling detection. Organization of the Co-ordinated Research Programme (CRP) on signal processing techniques for sodium boiling noise detection was also recommended at the 16th meeting of the IWGFR. The CRP on Signal Processing Techniques for Sodium Boiling Noise Detection was set up in 1984. Eight laboratories from six countries have agreed to participate in this CRP. The overall objective of the programme was the development of reliable on-line signal processing techniques which could be used for the detection of sodium boiling in an LMFBR core. During the first stage of the programme a number of existing processing techniques used by different countries have been compared and evaluated. In the course of further work, an algorithm for implementation of this sodium boiling detection system in the nuclear reactor will be developed. It was also considered that the acoustic signal processing techniques developed for boiling detection could well make a useful contribution to other acoustic applications in the reactor. This publication consists of two parts. Part I is the final report of the co-ordinated research programme on signal processing techniques for sodium boiling noise detection. Part II contains two introductory papers and 20 papers presented at four research co-ordination meetings since 1985. A separate abstract was prepared for each of these 22 papers. Refs, figs and tabs

  2. Early tumour detection: a transillumination, time-resolved technique

    International Nuclear Information System (INIS)

    Behin-Ain, S.; Van Doorn, T.; Patterson, J.

    2000-01-01

    Full text: Research into transillumination techniques for the detection of tumours in soft tissue has been ongoing for over 70 years. The resolution and contrast, however, remain severely limited by scatter. Single photon detection techniques, with ideally infinite extinction coefficients, have been proposed to accumulate sub-hertz photon transmitted frequencies in the early part of a transmitted pulse. Computer based simulations have been undertaken to examine the theoretical performance requirements of the detector and the resultant image qualities that may be expected with this imaging technique. This paper reports on the computational techniques required for implementing these simulations in an efficient manner. Controlled Monte Carlo (CMC) and Convolution of Layers (CL) techniques were employed to constrain the photon to those having more chance of detection and hence enhance the detection statistics. Extrapolation techniques are proposed to reconstruct the early part of the temporal profile. Computational methods were implemented to evaluate Path Integrals, which are otherwise overly complex to evaluate. CMC and CL reduce the computational time by more than 10 orders of magnitude by only tracking those photons more likely to reach the detector. In the case of an optically thick medium with high scattering coefficient, extrapolation techniques are used to reconstruct the early part of temporal profile. Analytical solutions were found to be too involved for the simplest geometries. However the CL and implementation of computational techniques make Path integrals a useful analytical tool to compliment full Monte Carlo techniques. Results have shown that these methods collectively enable detection of small inhomogeneites within soft tissues. Reduced computation times and full reconstruction of the temporal profile of transmitted photons through optically thick medium enable fast simulations of single photon detectors to be achieved with the above described

  3. Active neutron technique for detecting attempted special nuclear material diversion

    International Nuclear Information System (INIS)

    Smith, G.W.; Rice, L.G. III.

    1979-01-01

    The identification of special nuclear material (SNM) diversion is necessary if SNM inventory control is to be maintained at nuclear facilities. (Special nuclear materials are defined for this purpose as either 235 U of 239 Pu.) Direct SNM identification by the detection of natural decay or fission radiation is inadequate if the SNM is concealed by appropriate shielding. The active neutron interrogation technique described combines direct SNM identification by delayed fission neutron (DFN) detection with implied SNM detection by the identification of materials capable of shielding SNM from direct detection. This technique is being developed for application in an unattended material/equipment portal through which items such as electronic instruments, packages, tool boxes, etc., will pass. The volume of this portal will be 41-cm wide, 53-cm high and 76-cm deep. The objective of this technique is to identify an attempted diversion of at least 20 grams of SNM with a measurement time of 30 seconds

  4. Kinetic and diagnostic studies of molecular plasmas using laser absorption techniques

    NARCIS (Netherlands)

    Welzel, S.; Rousseau, A.; Davies, P.B.; Röpcke, J.

    2007-01-01

    Within the last decade mid infrared absorption spectroscopy between 3 and 20 µm, known as Infrared Laser Absorption Spectroscopy (IRLAS) and based on tuneable semiconductor lasers, namely lead salt diode lasers, often called tuneable diode lasers (TDL), and quantum cascade lasers (QCL) has

  5. Label and Label-Free Detection Techniques for Protein Microarrays

    Directory of Open Access Journals (Sweden)

    Amir Syahir

    2015-04-01

    Full Text Available Protein microarray technology has gone through numerous innovative developments in recent decades. In this review, we focus on the development of protein detection methods embedded in the technology. Early microarrays utilized useful chromophores and versatile biochemical techniques dominated by high-throughput illumination. Recently, the realization of label-free techniques has been greatly advanced by the combination of knowledge in material sciences, computational design and nanofabrication. These rapidly advancing techniques aim to provide data without the intervention of label molecules. Here, we present a brief overview of this remarkable innovation from the perspectives of label and label-free techniques in transducing nano‑biological events.

  6. GBT Detection of Polarization-Dependent HI Absorption and HI Outflows in Local ULIRGs and Quasars

    Science.gov (United States)

    Teng, Stacy H.; Veilleux, Sylvain; Baker, Andrew J.

    2013-01-01

    We present the results of a 21-cm HI survey of 27 local massive gas-rich late-stage mergers and merger remnants with the Green Bank Telescope (GBT). These remnants were selected from the Quasar/ULIRG Evolution Study (QUEST) sample of ultraluminous infrared galaxies (ULIRGs; L(sub 8 - 1000 micron) > 10(exp 12) solar L) and quasars; our targets are all bolometrically dominated by active galactic nuclei (AGN) and sample the later phases of the proposed ULIRG-to-quasar evolutionary sequence. We find the prevalence of HI absorption (emission) to be 100% (29%) in ULIRGs with HI detections, 100% (88%) in FIR-strong quasars, and 63% (100%) in FIR-weak quasars. The absorption features are associated with powerful neutral outflows that change from being mainly driven by star formation in ULIRGs to being driven by the AGN in the quasars. These outflows have velocities that exceed 1500 km/s in some cases. Unexpectedly, we find polarization-dependent HI absorption in 57% of our spectra (88% and 63% of the FIR-strong and FIR-weak quasars, respectively). We attribute this result to absorption of polarized continuum emission from these sources by foreground HI clouds. About 60% of the quasars displaying polarized spectra are radio-loud, far higher than the approx 10% observed in the general AGN population. This discrepancy suggests that radio jets play an important role in shaping the environments in these galaxies. These systems may represent a transition phase in the evolution of gas-rich mergers into "mature" radio galaxies.

  7. Study of laser radar system using the differential absorption method for detection of air pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Inomata, H; Igarashi, T

    1975-11-01

    A laser radar system using the differential absorption method for remote measurement of atmospheric NO/sub 2/ and SO/sub 2/ is studied. A simultaneous two-wavelength dye laser for the transmitter and a simultaneous two-wavelength signal processer for the receiver are developed. In using this technique, one laser shot allows the determination of NO/sub 2/ concentrations with an uncertainty equivalent to 44 ppM times the range interval (in meters). It seems that the technique is most promising for a range-resolved measurement of ambient molecular pollutants, since it has the advantage of canceling the effect of atmospheric variation in a measurement when atmospheric aerosols are used as a distributed reflector.

  8. Selection of the optimal combination of water vapor absorption lines for detection of temperature in combustion zones of mixing supersonic gas flows by diode laser absorption spectrometry

    International Nuclear Information System (INIS)

    Mironenko, V.R.; Kuritsyn, Yu.A.; Bolshov, M.A.; Liger, V.V.

    2017-01-01

    Determination of a gas medium temperature by diode laser absorption spectrometry (DLAS) is based on the measurement of integral intensities of the absorption lines of a test molecule (generally water vapor molecule). In case of local thermodynamic equilibrium temperature is inferred from the ratio of the integral intensities of two lines with different low energy levels. For the total gas pressure above 1 atm the absorption lines are broadened and one cannot find isolated well resolved water vapor absorption lines within relatively narrow spectral interval of fast diode laser (DL) tuning range (about 3 cm"−"1). For diagnostics of a gas object in the case of high temperature and pressure DLAS technique can be realized with two diode lasers working in different spectral regions with strong absorption lines. In such situation the criteria of the optimal line selection differs significantly from the case of narrow lines. These criteria are discussed in our work. The software for selection the optimal spectral regions using the HITRAN-2012 and HITEMP data bases is developed. The program selects spectral regions of DL tuning, minimizing the error of temperature determination δT/T, basing on the attainable experimental error of line intensity measurement δS. Two combinations of optimal spectral regions were selected – (1.392 & 1.343 μm) and (1.392 & 1.339 μm). Different algorithms of experimental data processing are discussed.

  9. The Hydrogen Detection Technique for SG Protection System

    International Nuclear Information System (INIS)

    Lv Mingyu; Pei Zhiyong; Yu Huajin

    2015-01-01

    SG that is pressure boundary between secondary loop and triple loop is the key equipment of fast reactor, in which heat in secondary loop is transferred to water or steam in triple loop. According to data from IAEA, SG is the highest failure rate equipment in fast reactor, especially because of failure of heat transfer tube. In order to monitor failure of heat transfer tube, Fast Reactor Engineering Department develops diffusion type hydrogen detection system, which is used to detect sodium-water reaction in time. This paper firstly introduces experimental research scheme and results of this hydrogen detection technique; Subsequently, it is described that how this technique can be engineering realized in CEFR; Moreover, through developing a series of calibration tests and hydrogen injection tests, it is obtained that sensitivity, response time and calibration curse for hydrogen detection system of CEFR. (author)

  10. Left and right-hand guitar playing techniques detection

    OpenAIRE

    Reboursière, Loïc; Lähdeoja, Otso; Drugman, Thomas; Dupont, Stéphane; Picard-Limpens, Cécile; Riche, Nicolas

    2012-01-01

    In this paper we present a series of algorithms developed to detect the following guitar playing techniques : bend, hammer-on, pull-off, slide, palm muting and harmonic. Detection of playing techniques can be used to control exter-nal content (i.e audio loops and effects, videos, light events, etc.), as well as to write real-time score or to assist guitar novices in their learning process. The guitar used is a Godin Multiac with an under-saddle RMC hexaphonic piezo pickup (one pickup per stri...

  11. Fundamentals of electrochemical detection techniques for CE and MCE.

    Science.gov (United States)

    Kubán, Pavel; Hauser, Peter C

    2009-10-01

    The electroanalytical techniques of amperometry, conductometry and potentiometry match well with the instrumental simplicity of CE. Indeed, all three detection approaches have been reported for electrophoretic separations. However, the characteristics of the three methods are quite distinct and these are not related to the optical methods more commonly employed. A detailed discussion of the underlying principles of each is given. The issue of possible effects of the separation voltage on the electrochemical detection techniques is considered in depth, and approaches to the elimination of such interferences are also discussed for each case.

  12. Evaluation of Anomaly Detection Techniques for SCADA Communication Resilience

    OpenAIRE

    Shirazi, Syed Noor Ul Hassan; Gouglidis, Antonios; Syeda, Kanza Noor; Simpson, Steven; Mauthe, Andreas Ulrich; Stephanakis, Ioannis M.; Hutchison, David

    2016-01-01

    Attacks on critical infrastructures’ Supervisory Control and Data Acquisition (SCADA) systems are beginning to increase. They are often initiated by highly skilled attackers, who are capable of deploying sophisticated attacks to exfiltrate data or even to cause physical damage. In this paper, we rehearse the rationale for protecting against cyber attacks and evaluate a set of Anomaly Detection (AD) techniques in detecting attacks by analysing traffic captured in a SCADA network. For this purp...

  13. Simulation of land mine detection processes using nuclear techniques

    International Nuclear Information System (INIS)

    Aziz, M.

    2005-01-01

    A computer models were designed to study the processes of land mine detection using nuclear technique. Parameters that affect the detection were analyzed . Mines of different masses at different depths in the soil are considered using two types of sources , 252 C f and 14 MeV neutron source. The capability to differentiate between mines and other objects such as concrete , iron , wood , Aluminum ,water and polyethylene were analyzed and studied

  14. Masked-backlighter technique used to simultaneously image x-ray absorption and x-ray emission from an inertial confinement fusion plasma

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, F. J., E-mail: fredm@lle.rochester.edu; Radha, P. B. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2014-11-15

    A method to simultaneously image both the absorption and the self-emission of an imploding inertial confinement fusion plasma has been demonstrated on the OMEGA Laser System. The technique involves the use of a high-Z backlighter, half of which is covered with a low-Z material, and a high-speed x-ray framing camera aligned to capture images backlit by this masked backlighter. Two strips of the four-strip framing camera record images backlit by the high-Z portion of the backlighter, while the other two strips record images aligned with the low-Z portion of the backlighter. The emission from the low-Z material is effectively eliminated by a high-Z filter positioned in front of the framing camera, limiting the detected backlighter emission to that of the principal emission line of the high-Z material. As a result, half of the images are of self-emission from the plasma and the other half are of self-emission plus the backlighter. The advantage of this technique is that the self-emission simultaneous with backlighter absorption is independently measured from a nearby direction. The absorption occurs only in the high-Z backlit frames and is either spatially separated from the emission or the self-emission is suppressed by filtering, or by using a backlighter much brighter than the self-emission, or by subtraction. The masked-backlighter technique has been used on the OMEGA Laser System to simultaneously measure the emission profiles and the absorption profiles of polar-driven implosions.

  15. Masked-backlighter technique used to simultaneously image x-ray absorption and x-ray emission from an inertial confinement fusion plasma.

    Science.gov (United States)

    Marshall, F J; Radha, P B

    2014-11-01

    A method to simultaneously image both the absorption and the self-emission of an imploding inertial confinement fusion plasma has been demonstrated on the OMEGA Laser System. The technique involves the use of a high-Z backlighter, half of which is covered with a low-Z material, and a high-speed x-ray framing camera aligned to capture images backlit by this masked backlighter. Two strips of the four-strip framing camera record images backlit by the high-Z portion of the backlighter, while the other two strips record images aligned with the low-Z portion of the backlighter. The emission from the low-Z material is effectively eliminated by a high-Z filter positioned in front of the framing camera, limiting the detected backlighter emission to that of the principal emission line of the high-Z material. As a result, half of the images are of self-emission from the plasma and the other half are of self-emission plus the backlighter. The advantage of this technique is that the self-emission simultaneous with backlighter absorption is independently measured from a nearby direction. The absorption occurs only in the high-Z backlit frames and is either spatially separated from the emission or the self-emission is suppressed by filtering, or by using a backlighter much brighter than the self-emission, or by subtraction. The masked-backlighter technique has been used on the OMEGA Laser System to simultaneously measure the emission profiles and the absorption profiles of polar-driven implosions.

  16. Technique of experimental evaluation of cloud environment attacks detection accuracy

    Directory of Open Access Journals (Sweden)

    Sergey A. Klimachev

    2018-05-01

    Full Text Available The article is devoted to research of efficiency evaluation of IDS used for dynamic and complex organizational and technical structure computing platform guard. The components of the platform have a set of heterogeneous parameters. Analysis of existing IDS evaluation technique revealed shortcomings in justification of quantitative metrics that describe the efficiency and reliability IDS resolving. This makes if difficult to prove IDS evaluation technique. The purpose of the study is to increase IDS evaluation objectivity. To achive the purpose it is necessary to develop the correct technique, tools, experimental stand. The article proposes the results of development and approbation of the technique of IDS efficiency evaluation and software for it. The technique is based on defining of optimal set of attack detection accuracy scores. The technique and the software allow solving problems of comparative analysis of IDS that have similar functionality. As a result of the research, a number of task have been solved, including the selection of universal quantitative metrics for attack detection accuracy evaluation, the defining of summarised attack detection accuracy evaluation metric based on defining of pareto-optimal set of scores that ensure the confidentiality, integrity and accessibility of cloud environment information and information resources,  the development of a functional model,  a functional scheme and a software for cloud environment IDS research.

  17. Specific absorption spectra of hemoglobin at different PO2 levels: potential noninvasive method to detect PO2 in tissues.

    Science.gov (United States)

    Liu, Peipei; Zhu, Zhirong; Zeng, Changchun; Nie, Guang

    2012-12-01

    Hemoglobin (Hb), as one of main components of blood, has a unique quaternary structure. Its release of oxygen is controlled by oxygen partial pressure (PO2). We investigate the specific spectroscopic changes in Hb under different PO2 levels to optimize clinical methods of measuring tissue PO2. The transmissivity of Hb under different PO2 levels is measured with a UV/Vis fiber optic spectrometer. Its plotted absorption spectral curve shows two high absorption peaks at 540 and 576 nm and an absorption valley at 560 nm when PO2 is higher than 100 mm Hg. The two high absorption peaks decrease gradually with a decrease in PO2, whereas the absorption valley at 560 nm increases. When PO2 decreases to approximately 0 mm Hg, the two high absorption peaks disappear completely, while the absorption valley has a hypochromic shift (8 to 10 nm) and forms a specific high absorption peak at approximately 550 nm. The same phenomena can be observed in visible reflectance spectra of finger-tip microcirculation. Specific changes in extinction coefficient and absorption spectra of Hb occur along with variations in PO2, which could be used to explain pathological changes caused by tissue hypoxia and for early detection of oxygen deficiency diseases in clinical monitoring.

  18. Prediction of Human Intestinal Absorption of Compounds Using Artificial Intelligence Techniques.

    Science.gov (United States)

    Kumar, Rajnish; Sharma, Anju; Siddiqui, Mohammed Haris; Tiwari, Rajesh Kumar

    2017-01-01

    Information about Pharmacokinetics of compounds is an essential component of drug design and development. Modeling the pharmacokinetic properties require identification of the factors effecting absorption, distribution, metabolism and excretion of compounds. There have been continuous attempts in the prediction of intestinal absorption of compounds using various Artificial intelligence methods in the effort to reduce the attrition rate of drug candidates entering to preclinical and clinical trials. Currently, there are large numbers of individual predictive models available for absorption using machine learning approaches. Six Artificial intelligence methods namely, Support vector machine, k- nearest neighbor, Probabilistic neural network, Artificial neural network, Partial least square and Linear discriminant analysis were used for prediction of absorption of compounds. Prediction accuracy of Support vector machine, k- nearest neighbor, Probabilistic neural network, Artificial neural network, Partial least square and Linear discriminant analysis for prediction of intestinal absorption of compounds was found to be 91.54%, 88.33%, 84.30%, 86.51%, 79.07% and 80.08% respectively. Comparative analysis of all the six prediction models suggested that Support vector machine with Radial basis function based kernel is comparatively better for binary classification of compounds using human intestinal absorption and may be useful at preliminary stages of drug design and development. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. Optical resonance-enhanced absorption-based near-field immunochip biosensor for allergen detection.

    Science.gov (United States)

    Maier, Irene; Morgan, Michael R A; Lindner, Wolfgang; Pittner, Fritz

    2008-04-15

    An optical immunochip biosensor has been developed as a rapid method for allergen detection in complex food matrixes, and its application evaluated for the detection of the egg white allergens, ovalbumin and ovomucoid. The optical near-field phenomenon underlying the basic principle of the sensor design is called resonance-enhanced absorption (REA), which utilizes gold nanoparticles (Au NPs) as signal transducers in a highly sensitive interferometric setup. Using this approach, a novel, simple, and rapid colorimetric solid-phase immunoassay on a planar chip substrate was realized in direct and sandwich assay formats, with a detection system that does not require any instrumentation for readout. Semiquantitative immunochemical responses are directly visible to the naked eye of the analyst. The biosensor shows concentration-dependent color development by capturing antibody-functionalized Au NPs on allergen-coated chips and has a detection limit of 1 ng/mL. To establish a rapid method, we took advantage of the physicochemical microenvironment of the Au NP-antibody bioconjugate to be bound directly over an interacting poly(styrene-methyl methacrylate) interlayer by an immobilized antigen. In the direct assay format, a coating time with allergen of only 5 min under "soft" nondenaturing conditions was sufficient for accurate reproducibility and sensitivity. In conclusion, the REA-based immunochip sensor is easy to fabricate, is reproducible and selective in its performance, has minimal technical requirements, and will enable high-throughput screening of affinity binding interactions in technological and medical applications.

  20. Comparison of survey techniques on detection of northern flying squirrels

    Science.gov (United States)

    Diggins, Corinne A.; Gilley, L. Michelle; Kelly, Christine A.; Ford, W. Mark

    2016-01-01

    The ability to detect a species is central to the success of monitoring for conservation and management purposes, especially if the species is rare or endangered. Traditional methods, such as live capture, can be labor-intensive, invasive, and produce low detection rates. Technological advances and new approaches provide opportunities to more effectively survey for species both in terms of accuracy and efficiency than previous methods. We conducted a pilot comparison study of a traditional technique (live-trapping) and 2 novel noninvasive techniques (camera-trapping and ultrasonic acoustic surveys) on detection rates of the federally endangered Carolina northern flying squirrel (Glaucomys sabrinus coloratus) in occupied habitat within the Roan Mountain Highlands of North Carolina, USA. In 2015, we established 3 5 × 5 live-trapping grids (6.5 ha) with 4 camera traps and 4 acoustic detectors systematically embedded in each grid. All 3 techniques were used simultaneously during 2 4-day survey periods. We compared techniques by assessing probability of detection (POD), latency to detection (LTD; i.e., no. of survey nights until initial detection), and survey effort. Acoustics had the greatest POD (0.37 ± 0.06 SE), followed by camera traps (0.30 ± 0.06) and live traps (0.01 ± 0.005). Acoustics had a lower LTD than camera traps (P = 0.017), where average LTD was 1.5 nights for acoustics and 3.25 nights for camera traps. Total field effort was greatest with live traps (111.9 hr) followed by acoustics (8.4 hr) and camera traps (9.6 hr), although processing and examination for data of noninvasive techniques made overall effort similar among the 3 methods. This pilot study demonstrated that both noninvasive methods were better rapid-assessment detection techniques for flying squirrels than live traps. However, determining seasonal effects between survey techniques and further development of protocols for both noninvasive techniques is

  1. Research on ultrasonic flow detection techniques for LWR facilities

    International Nuclear Information System (INIS)

    Kimura, Katsumi; Fukuhara, Hiroaki; Hoshimoto, Kenichi; Matsumoto, Shojiro; Yamawaki, Hisashi; Ito, Hideyuki; Uetake, Ichizo

    1986-01-01

    Aiming at establishing the techniques for inspecting the inside of LWR pressure vessels by ultrasonic flaw detection from the outside of the vessels, the development of a probe suitable to the flaw detection in the thick steel plates with stainless steel overlay and the method of its driving, the examination of the ultrasonic characteristics of austenitic stainless steel welded metal used for overlay, and the improvement of the detectability of defects and the accuracy of measuring dimensions by the application of signal processing techniques to ultrasonic flaw detection were attempted. In order to cope with the impedance lowering accompanying the increase of oscillator size, the oscillator was divided into the rings with equal area, and the driving and signal receiving were carried out individually, in this way, the good results were obtained by summing the signals. It was theoretically proved that it is rational to use longitudinal waves for the flaw detection in overlay. It was found that by displaying the results of flaw detection as pictures using a microcomputer, the capability of defect detection was increased. Also by the signal processing combining Fourier transformation and filtering, noise removal and the heightening of the accuracy of measuring dimensions were able to be attained. (Kako, I.)

  2. Robustness of movement detection techniques from motor execution

    DEFF Research Database (Denmark)

    Aliakbaryhosseinabadi, Susan; Jiang, Ning; Petrini, Laura

    2015-01-01

    subjects completed a set of movement executions prior to and following the oddball paradigm. The locality preserving projection followed by the linear discriminant analysis (LPP-LDA) and the matched-filter (MF) technique were applied offline for detection of movement. Results show that LPP...

  3. Detection of Glaucoma Using Image Processing Techniques: A Critique.

    Science.gov (United States)

    Kumar, B Naveen; Chauhan, R P; Dahiya, Nidhi

    2018-01-01

    The primary objective of this article is to present a summary of different types of image processing methods employed for the detection of glaucoma, a serious eye disease. Glaucoma affects the optic nerve in which retinal ganglion cells become dead, and this leads to loss of vision. The principal cause is the increase in intraocular pressure, which occurs in open-angle and angle-closure glaucoma, the two major types affecting the optic nerve. In the early stages of glaucoma, no perceptible symptoms appear. As the disease progresses, vision starts to become hazy, leading to blindness. Therefore, early detection of glaucoma is needed for prevention. Manual analysis of ophthalmic images is fairly time-consuming and accuracy depends on the expertise of the professionals. Automatic analysis of retinal images is an important tool. Automation aids in the detection, diagnosis, and prevention of risks associated with the disease. Fundus images obtained from a fundus camera have been used for the analysis. Requisite pre-processing techniques have been applied to the image and, depending upon the technique, various classifiers have been used to detect glaucoma. The techniques mentioned in the present review have certain advantages and disadvantages. Based on this study, one can determine which technique provides an optimum result.

  4. Outlier Detection Techniques For Wireless Sensor Networks: A Survey

    NARCIS (Netherlands)

    Zhang, Y.; Meratnia, Nirvana; Havinga, Paul J.M.

    2008-01-01

    In the field of wireless sensor networks, measurements that significantly deviate from the normal pattern of sensed data are considered as outliers. The potential sources of outliers include noise and errors, events, and malicious attacks on the network. Traditional outlier detection techniques are

  5. Changepoint detection techniques for VoIP traffic

    NARCIS (Netherlands)

    Mandjes, M.; Zuraniewski, P.W.

    2013-01-01

    The control of communication networks critically relies on procedures capable of detecting unanticipated load changes. In this chapter we present an overview of such techniques, in a setting in which each connection consumes roughly the same amount of bandwidth (with VoIP as a leading example). For

  6. Changepoint Detection Techniques for VoIP Traffic

    NARCIS (Netherlands)

    Mandjes, M.; Żuraniewski, P.; Biersack, E.; Callegari, C.; Matijasevic, M.

    2013-01-01

    The control of communication networks critically relies on procedures capable of detecting unanticipated load changes. In this chapter we present an overview of such techniques, in a setting in which each connection consumes roughly the same amount of bandwidth (with VoIP as a leading example). For

  7. Comparative studies of method for determining total mercury in fish. Dithizone and flameless atomic absorption spectrophotometry techniques

    International Nuclear Information System (INIS)

    Protasowicki, M.; Ociepa, A.; Chodyniecki, A.

    1977-01-01

    Two methods for determining total mercury in fish were compared: the dithizone and flameless atomic absorption spectrophotometry techniques. The studies involved determination of recovery when 1μg of mercury as solutions of HgCl 2 or CH 3 HgC were added to each sample of herring flesh. Mean recoveries in the dithizone method were found to be 91.4+-7.47% and 90.25+-4.73% for the two solutions respectively, while the recoveries obtained with the flameless atomic absorption spectrophotometry were 95.00+-9.13% and 98.70+-7.14%, respectively. Both techniques were used to determine the mercury content in the same herring flesh sample. The first technique showed the content of 0.050+-0.018μg Hg g -1 while the result obtained with the other one was 0.062+-0.013μg Hg g -1 . The statistical treatment of the results obtained showed no difference between the two techniques, the significance level being α=0.05. Therefore, the results obtained with the dithizone method are comparable with those obtained with the flameless atomic absorption spectrophotometry for mercury contents of the magnitude order of 0.050 ug.g -1 . (author)

  8. Infrared absorption of gaseous ClCS detected with time-resolved Fourier-transform spectroscopy

    International Nuclear Information System (INIS)

    Chu, Li-Kang; Han, Hui-Ling; Lee, Yuan-Pern

    2007-01-01

    A transient infrared absorption spectrum of gaseous ClCS was detected with a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. ClCS was produced upon irradiating a flowing mixture of Cl 2 CS and N 2 or CO 2 with a KrF excimer laser at 248 nm. A transient band in the region of 1160-1220 cm -1 , which diminished on prolonged reaction, is assigned to the C-S stretching (ν 1 ) mode of ClCS. Calculations with density-functional theory (B3P86 and B3LYP/aug-cc-pVTZ) predict the geometry, vibrational wave numbers, and rotational parameters of ClCS. The rotational contour of the spectrum of ClCS simulated based on predicted rotational parameters agrees satisfactorily with experimental observation; from spectral simulation, the band origin is determined to be at 1194.4 cm -1 . Reaction kinetics involving ClCS, CS, and CS 2 are discussed

  9. The 'sniffer-patch' technique for detection of neurotransmitter release.

    Science.gov (United States)

    Allen, T G

    1997-05-01

    A wide variety of techniques have been employed for the detection and measurement of neurotransmitter release from biological preparations. Whilst many of these methods offer impressive levels of sensitivity, few are able to combine sensitivity with the necessary temporal and spatial resolution required to study quantal release from single cells. One detection method that is seeing a revival of interest and has the potential to fill this niche is the so-called 'sniffer-patch' technique. In this article, specific examples of the practical aspects of using this technique are discussed along with the procedures involved in calibrating these biosensors to extend their applications to provide quantitative, in addition to simple qualitative, measurements of quantal transmitter release.

  10. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques

    Directory of Open Access Journals (Sweden)

    O. Schmid

    2006-01-01

    Full Text Available Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP, have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ Aethalometer became commercially available, which covers the visible (VIS to near-infrared (NIR spectral range (λ=450–950 nm, and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999. On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering, which is significantly larger than the factors previously reported (~2 for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external as a likely cause. For

  11. Zinc Absorption from Representative Diet in a Chinese Elderly Population Using Stable Isotope Technique.

    Science.gov (United States)

    Li, Ya Jie; Li, Min; Liu, Xiao Bing; Ren, Tong Xiang; Li, Wei Dong; Yang, Chun; Wu, Meng; Yang, Lin Li; Ma, Yu Xia; Wang, Jun; Piao, Jian Hua; Yang, Li Chen; Yang, Xiao Guang

    2017-06-01

    To determine the dietary zinc absorption in a Chinese elderly population and provide the basic data for the setting of zinc (Zn) recommended nutrient intakes (RNI) for Chinese elderly people. A total of 24 elderly people were recruited for this study and were administered oral doses of 3 mg 67Zn and 1.2 mg dysprosium on the fourth day. The primary macronutrients, energy, and phytic acid in the representative diet were examined based on the Chinese National Standard Methods. Fecal samples were collected during the experimental period and analyzed for zinc content, 67Zn isotope ratio, and dysprosium content. The mean (± SD) zinc intake from the representative Chinese diet was 10.6 ± 1.5 mg/d. The phytic acid-to-zinc molar ratio in the diet was 6.4. The absorption rate of 67Zn was 27.9% ± 9.2%. The RNI of zinc, which were calculated by the absorption rate in elderly men and women, were 10.4 and 9.2 mg/d, respectively. This study got the dietary Zn absorption in a Chinese elderly population. We found that Zn absorption was higher in elderly men than in elderly women. The current RNI in elderly female is lower than our finding, which indicates that more attention is needed regarding elderly females' zinc status and health. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  12. Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane--Breath Biomarkers of Serious Diseases.

    Science.gov (United States)

    Wojtas, Jacek

    2015-06-17

    The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (laser and a tunable laser system consisting of an optical parametric oscillator and difference frequency generator. Setup using the first source provided a detection limit of 30 ppb for nitric oxide and 250 ppb for carbonyl sulphide. During experiments employing a second laser, detection limits of 0.9 ppb and 0.3 ppb were obtained for carbonyl sulphide and ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases.

  13. Diffuse-light absorption spectroscopy by fiber optics for detecting and quantifying the adulteration of extra virgin olive oil

    Science.gov (United States)

    Mignani, A. G.; Ciaccheri, L.; Ottevaere, H.; Thienpont, H.; Conte, L.; Marega, M.; Cichelli, A.; Attilio, C.; Cimato, A.

    2010-09-01

    A fiber optic setup for diffuse-light absorption spectroscopy in the wide 400-1700 nm spectral range is experimented for detecting and quantifying the adulteration of extra virgin olive oil caused by lower-grade olive oils. Absorption measurements provide spectral fingerprints of authentic and adulterated oils. A multivariate processing of spectroscopic data is applied for discriminating the type of adulterant and for predicting its fraction.

  14. 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)

  15. A review of whole-body counting techniques appropriate to the study of gastrointestinal absorption

    International Nuclear Information System (INIS)

    Boddy, K.

    1976-01-01

    The wide range of whole-body counters in use for, or applicable to, the study of gastrointestinal absorption is reviewed. Shielded-room or high-sensitivity shadow-shield counters will generally be required only when there is a separate need to measure total body potassium or in studies involving pregnancy or children. For measuring gastrointestinal absorption per se, it is concluded that very simple whole-body counters of the shadow-shield or partial-shield type are usually satisfactory. These systems are of lower cost, and an economic justification for their use is derived by comparing their costs with those of hospitalizing patients for alternative investigations of gastrointestinal absorption. A resume of the general methodology is presented and some operational features and precautions are described. (author)

  16. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    Energy Technology Data Exchange (ETDEWEB)

    Isomura, Noritake, E-mail: isomura@mosk.tytlabs.co.jp [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Soejima, Narumasa; Iwasaki, Shiro [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Nomoto, Toyokazu; Murai, Takaaki [Aichi Synchrotron Radiation Center (AichiSR), 250-3 Minamiyamaguchi-cho, Seto, Aichi 489-0965 (Japan); Kimoto, Yasuji [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)

    2015-11-15

    Graphical abstract: - Highlights: • A unique XAS method is proposed for depth profiling of chemical states. • PEY mode detecting energy-loss electrons enables a variation in the probe depth. • Si K-edge XAS spectra of the Si{sub 3}N{sub 4}/SiO{sub 2}/Si multilayer films have been investigated. • Deeper information was obtained in the spectra measured at larger energy loss. • Probe depth could be changed by the selection of the energy of detected electrons. - Abstract: A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si{sub 3}N{sub 4}/SiO{sub 2}/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  17. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    International Nuclear Information System (INIS)

    Isomura, Noritake; Soejima, Narumasa; Iwasaki, Shiro; Nomoto, Toyokazu; Murai, Takaaki; Kimoto, Yasuji

    2015-01-01

    Graphical abstract: - Highlights: • A unique XAS method is proposed for depth profiling of chemical states. • PEY mode detecting energy-loss electrons enables a variation in the probe depth. • Si K-edge XAS spectra of the Si_3N_4/SiO_2/Si multilayer films have been investigated. • Deeper information was obtained in the spectra measured at larger energy loss. • Probe depth could be changed by the selection of the energy of detected electrons. - Abstract: A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si_3N_4/SiO_2/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  18. UV Absorption Spectroscopy in Water-Filled Antiresonant Hollow Core Fibers for Pharmaceutical Detection.

    Science.gov (United States)

    Nissen, Mona; Doherty, Brenda; Hamperl, Jonas; Kobelke, Jens; Weber, Karina; Henkel, Thomas; Schmidt, Markus A

    2018-02-06

    Due to a worldwide increased use of pharmaceuticals and, in particular, antibiotics, a growing number of these substance residues now contaminate natural water resources and drinking supplies. This triggers a considerable demand for low-cost, high-sensitivity methods for monitoring water quality. Since many biological substances exhibit strong and characteristic absorption features at wavelengths shorter than 300 nm, UV spectroscopy presents a suitable approach for the quantitative identification of such water-contaminating species. However, current UV spectroscopic devices often show limited light-matter interaction lengths, demand sophisticated and bulky experimental infrastructure which is not compatible with microfluidics, and leave large fractions of the sample analyte unused. Here, we introduce the concept of UV spectroscopy in liquid-filled anti-resonant hollow core fibers, with large core diameters and lengths of approximately 1 m, as a means to overcome such limitations. This extended light-matter interaction length principally improves the concentration detection limit by two orders of magnitude while using almost the entire sample volume-that is three orders of magnitude smaller compared to cuvette based approaches. By integrating the fibers into an optofluidic chip environment and operating within the lowest experimentally feasible transmission band, concentrations of the application-relevant pharmaceutical substances, sulfamethoxazole (SMX) and sodium salicylate (SS), were detectable down to 0.1 µM (26 ppb) and 0.4 µM (64 ppb), respectively, with the potential to reach significantly lower detection limits for further device integration.

  19. UV Absorption Spectroscopy in Water-Filled Antiresonant Hollow Core Fibers for Pharmaceutical Detection

    Directory of Open Access Journals (Sweden)

    Mona Nissen

    2018-02-01

    Full Text Available Due to a worldwide increased use of pharmaceuticals and, in particular, antibiotics, a growing number of these substance residues now contaminate natural water resources and drinking supplies. This triggers a considerable demand for low-cost, high-sensitivity methods for monitoring water quality. Since many biological substances exhibit strong and characteristic absorption features at wavelengths shorter than 300 nm, UV spectroscopy presents a suitable approach for the quantitative identification of such water-contaminating species. However, current UV spectroscopic devices often show limited light-matter interaction lengths, demand sophisticated and bulky experimental infrastructure which is not compatible with microfluidics, and leave large fractions of the sample analyte unused. Here, we introduce the concept of UV spectroscopy in liquid-filled anti-resonant hollow core fibers, with large core diameters and lengths of approximately 1 m, as a means to overcome such limitations. This extended light-matter interaction length principally improves the concentration detection limit by two orders of magnitude while using almost the entire sample volume—that is three orders of magnitude smaller compared to cuvette based approaches. By integrating the fibers into an optofluidic chip environment and operating within the lowest experimentally feasible transmission band, concentrations of the application-relevant pharmaceutical substances, sulfamethoxazole (SMX and sodium salicylate (SS, were detectable down to 0.1 µM (26 ppb and 0.4 µM (64 ppb, respectively, with the potential to reach significantly lower detection limits for further device integration.

  20. [Detecting Thallium in Water Samples using Dispersive Liquid Phase Microextraction-Graphite Furnace Atomic Absorption Spectroscopy].

    Science.gov (United States)

    Zhu, Jing; Li, Yan; Zheng, Bo; Tang, Wei; Chen, Xiao; Zou, Xiao-li

    2015-11-01

    To develope a method of solvent demulsification dispersive liquid phase microextraction (SD-DLPME) based on ion association reaction coupled with graphite furnace atomic absorption spectroscopy (GFAAS) for detecting thallium in water samples. Methods Thallium ion in water samples was oxidized to Tl(III) with bromine water, which reacted with Cl- to form TlCl4-. The ionic associated compound with trioctylamine was obtained and extracted. DLPME was completed with ethanol as dispersive solvent. The separation of aqueous and organic phase was achieved by injecting into demulsification solvent without centrifugation. The extractant was collected and injected into GFAAS for analysis. With palladium colloid as matrix modifier, a two step drying and ashing temperature programming process was applied for high precision and sensitivity. The linear range was 0.05-2.0 microg/L, with a detection limit of 0.011 microg/L. The relative standard derivation (RSD) for detecting Tl in spiked water sample was 9.9%. The spiked recoveries of water samples ranged from 94.0% to 103.0%. The method is simple, sensitive and suitable for batch analysis of Tl in water samples.

  1. Study of non-validity of mixture rule near K-absorption edges by X-ray spectrometric technique

    International Nuclear Information System (INIS)

    Sharanabasappa; Chitralekha, A.; Kerur, B.R.; Anilkumar, S.

    2012-01-01

    X-ray spectrometric technique has been described to determine the X-ray mass attenuation coefficient, μ/ρ, of X-rays employing HPGe X-ray detector and radioactive sources. The photon intensity is measured by gating the channel of the spectrometer at FWHM/photo peak. Using the technique the 'best value' values of μ/ρ were obtained for those thicknesses which lie in the transmission (T) range 0.5 ≥ T ≥ 0.02. Total attenuation cross sections for other elements and lead compounds were measured at photon energies from 17 to 88 keV to study the Bragg's additivity law near the absorption edge of the lead. The measured values of mass attenuation coefficient values are compared with theoretical values obtained using Winxcom (programme). This study suggests that measured mass attenuation coefficient values at and near absorption edges differ from the theoretical value by about 17-23%. (author)

  2. Absorption and activation techniques in measurements of fast-neutron capture cross sections

    International Nuclear Information System (INIS)

    Bergqvist, I.

    1982-01-01

    The absorption and activation methods have been applied for a long time to systematic studies of fast neutron capture cross sections. Both methods are simple in principle but difficult in practice. The simplicity should ensure a wider use of the methods in particular for problems which may be complicated to approach with other methods. The difficulties encountered in absorption measurements are related to multiple scattering and resonance shielding effects. In activation experiments the influence of secondary low-energy neutrons causes the main problems

  3. $\\beta$-decay studies using total absorption techniques some recent results

    CERN Document Server

    Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Karny, M; Kirchner, R; Maréchal, F; Miehé, C; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Scornet, G L; Taín, J L; Tengblad, O; Wittmann, V

    2004-01-01

    $\\beta$-decay experiments, are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called $\\textit{Pandemonium effect}$ is a critical problem in $\\beta$-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (25 refs).

  4. Beta-decay studies using total absorption techniques: some recent results

    Energy Technology Data Exchange (ETDEWEB)

    Algora, A.; Rubio, B.; Nacher, E.; Cano O, D.; Tain, J.L.; Gadea, A. [lnstituto de Fisica Corpuscular, Apartado Oficial 22085, 46071 Valencia (Spain); Batist, L.; Moroz, F.; Wittmann, V. [St. Petersburg Nuclear Physics Institute, RU-188-350 Gatchina, (Russian Federation); Borge, M.J.G.; Jungclaus, A.; Tengblad, O. [Instituto Estructura de la Materia, E-28006 Madrid (Spain); Collatz, R.; Hellstrom, M.; Kirchner, R.; Roeckl, E. [Gesellschaft fur Schwerionenforschung, D-64291 Darmstadt (Germany); Courtin, H.; Dessagne, Ph.; Miehe, C.; Marechal, F.; Poirier, E. [lnstitut de Recherches Subatomiques, IN2P3-CNRS, F-67037 Strassbourg Cedex 2 (France); Fraile, L.M. [ISOLDE, Division EP, CERN, CH-1211 Geneva (Switzerland); Gelletly, W. [University of Surrey, Guildford GU2 7XH (United Kingdom); Janas, Z.; Karny, M.; Rykaczewski, K. [University of Warsaw, PL-00-681, Warsaw (Poland); Le Scornet, G. [CSNSM, 91405 Orsay (France)

    2004-12-01

    Beta-decay experiments are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on {gamma} ray spectroscopy, they face different experimental problems. The so called Pandemonium effect [1] is a critical problem in {beta}-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (Author) 25 refs., 4 figs.

  5. Analysis of algebraic reconstruction technique for accurate imaging of gas temperature and concentration based on tunable diode laser absorption spectroscopy

    International Nuclear Information System (INIS)

    Xia Hui-Hui; Kan Rui-Feng; Liu Jian-Guo; Xu Zhen-Yu; He Ya-Bai

    2016-01-01

    An improved algebraic reconstruction technique (ART) combined with tunable diode laser absorption spectroscopy(TDLAS) is presented in this paper for determining two-dimensional (2D) distribution of H 2 O concentration and temperature in a simulated combustion flame. This work aims to simulate the reconstruction of spectroscopic measurements by a multi-view parallel-beam scanning geometry and analyze the effects of projection rays on reconstruction accuracy. It finally proves that reconstruction quality dramatically increases with the number of projection rays increasing until more than 180 for 20 × 20 grid, and after that point, the number of projection rays has little influence on reconstruction accuracy. It is clear that the temperature reconstruction results are more accurate than the water vapor concentration obtained by the traditional concentration calculation method. In the present study an innovative way to reduce the error of concentration reconstruction and improve the reconstruction quality greatly is also proposed, and the capability of this new method is evaluated by using appropriate assessment parameters. By using this new approach, not only the concentration reconstruction accuracy is greatly improved, but also a suitable parallel-beam arrangement is put forward for high reconstruction accuracy and simplicity of experimental validation. Finally, a bimodal structure of the combustion region is assumed to demonstrate the robustness and universality of the proposed method. Numerical investigation indicates that the proposed TDLAS tomographic algorithm is capable of detecting accurate temperature and concentration profiles. This feasible formula for reconstruction research is expected to resolve several key issues in practical combustion devices. (paper)

  6. CO and CO2 dual-gas detection based on mid-infrared wideband absorption spectroscopy

    Science.gov (United States)

    Dong, Ming; Zhong, Guo-qiang; Miao, Shu-zhuo; Zheng, Chuan-tao; Wang, Yi-ding

    2018-03-01

    A dual-gas sensor system is developed for CO and CO2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing (TDM) technique. A stepper motor based rotating system and a single-reflection spherical optical mirror are designed and adopted for realizing and enhancing dual-gas detection. Detailed measurements under static detection mode (without rotation) and dynamic mode (with rotation) are performed to study the performance of the sensor system for the two gas samples. The detection period is 7.9 s in one round of detection by scanning the two detectors. Based on an Allan deviation analysis, the 1σ detection limits under static operation are 3.0 parts per million (ppm) in volume and 2.6 ppm for CO and CO2, respectively, and those under dynamic operation are 9.4 ppm and 10.8 ppm for CO and CO2, respectively. The reported sensor has potential applications in various fields requiring CO and CO2 detection such as in the coal mine.

  7. From Pacemaker to Wearable: Techniques for ECG Detection Systems.

    Science.gov (United States)

    Kumar, Ashish; Komaragiri, Rama; Kumar, Manjeet

    2018-01-11

    With the alarming rise in the deaths due to cardiovascular diseases (CVD), present medical research scenario places notable importance on techniques and methods to detect CVDs. As adduced by world health organization, technological proceeds in the field of cardiac function assessment have become the nucleus and heart of all leading research studies in CVDs in which electrocardiogram (ECG) analysis is the most functional and convenient tool used to test the range of heart-related irregularities. Most of the approaches present in the literature of ECG signal analysis consider noise removal, rhythm-based analysis, and heartbeat detection to improve the performance of a cardiac pacemaker. Advancements achieved in the field of ECG segments detection and beat classification have a limited evaluation and still require clinical approvals. In this paper, approaches on techniques to implement on-chip ECG detector for a cardiac pacemaker system are discussed. Moreover, different challenges regarding the ECG signal morphology analysis deriving from medical literature is extensively reviewed. It is found that robustness to noise, wavelet parameter choice, numerical efficiency, and detection performance are essential performance indicators required by a state-of-the-art ECG detector. Furthermore, many algorithms described in the existing literature are not verified using ECG data from the standard databases. Some ECG detection algorithms show very high detection performance with the total number of detected QRS complexes. However, the high detection performance of the algorithm is verified using only a few datasets. Finally, gaps in current advancements and testing are identified, and the primary challenge remains to be implementing bullseye test for morphology analysis evaluation.

  8. Absorption kinetics of vitamin E nanoemulsion and green tea microstructures by intestinal in situ single perfusion technique in rats.

    Science.gov (United States)

    Saratale, Rijuta Ganesh; Lee, Hee-Seok; Koo, Yong Eui; Saratale, Ganesh Dattatraya; Kim, Young Jun; Imm, Jee Young; Park, Yooheon

    2018-04-01

    The absorption kinetics of food ingredients such as nanoemulsified vitamin E and green tea microstructures were evaluated by the intestinal in situ single perfusion technique. Absorption rate, sub-acute oral toxicity and organ morphology in a rat model were examined. The intestinal in situ single perfusion technique and HPLC analysis were applied to investigate the absorption rate of selected materials by examining time-dependent changes in the serum levels of catechin and dl-α-tocopherol. The acute toxicity test and histopathological evaluation were applied to analyze the safety of microsized green tea and nanosized vitamin E in a rat model. Total serum dl-α-tocopherol levels significantly increased with nanosized vitamin E administration (PE until 90min after administration showed significantly increased absorption rate of serum dl-α-tocopherol levels at each time point (10min interval) (PE and microsized green tea did not show signs of acute toxicity or death after 14days of observation. In addition, macroscopic analysis showed that there were no changes in representative organ sections of rats following the oral administration of food-related nanoscale materials. We successfully demonstrated that using nanosized vitamin E increased absorption rate to a greater extent than normal food-related material, and these results occurs via safety analyses on food-related nanoscale materials for human consumption. These results could be useful for the design and development of novel nanoemulsified vitamin E and microsized green tea formulations that can overcome the problem of their bioavailability and improve their efficacy while still maintaining their essential therapeutic efficacies. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. A new and fast in-situ spectroscopic infrared absorption measurement technique

    NARCIS (Netherlands)

    Hest, van M.F.A.M.; Klaver, A.; Sanden, van de M.C.M.

    2001-01-01

    Silicon oxide like films are deposited using an expanding thermal plasma (cascaded arc) in combination with HMDSO and oxygen as deposition precursors. These films are deposited at high rate (up to 200 nm/s). In general Fourier transform infrared (FTIR) reflection absorption spectroscopy is a useful

  10. Absorption of magnesium in intestinal loop studied by the multitracer technique

    International Nuclear Information System (INIS)

    Yoshida, Shozo; Yamasaki, Mineo; Morikawa, Hajime

    2004-01-01

    We investigated Mg absorption in the intestine, and pregnancy-associated changes in Mg absorption by the rat everted gut sac method. Heavy ion beam accelerated by ring-cyclotron was irradiated to a titanium target and the radioactive multitracer solution which includes 28 Mg was made. 9 weeks old female Wistar rats (non-pregnancy, 6∼20th day of the pregnancy) were fasted overnight and anesthetized. Four segments of the intestine were isolated and everted to prepare sac specimens with mucosa outside. Each specimen was filled with multitracer solution and was immersed in the same solution. After incubation the multitracer solutions in both of inside and outside the sacs were removed. The radioactivity of the each sample was determined by gamma-ray spectrometry. In non-pregnant state, the active transport of Mg from mucosal side into serosal side exists only in colon. This active transport of Mg in colon during pregnancy was significantly decreased than in non-pregnant state. The mechanism and importance of the decrease in Mg absorption during pregnancy are still unclear. In humans, the intracellular and extracellular Mg concentrations decrease with the normal pregnancy course, especially in preeclampsia. The association between the changes in active Mg absorption during pregnancy and the pathogenesis should be clarified as early as possible. (author)

  11. Advanced detection techniques for educational experiments in cosmic ray physics

    International Nuclear Information System (INIS)

    Aiola, Salvatore; La-Rocca, Paola; Riggi, Francesco; Riggi, Simone

    2013-06-01

    In this paper we describe several detection techniques that can be employed to study cosmic ray properties and carry out training activities at high school and undergraduate level. Some of the proposed devices and instrumentation are inherited from professional research experiments, while others were especially developed and marketed for educational cosmic ray experiments. The educational impact of experiments in cosmic ray physics in high-school or undergraduate curricula will be exploited through various examples, going from simple experiments carried out with small Geiger counters or scintillation devices to more advanced detection instrumentation which can offer starting points for not trivial research work. (authors)

  12. Wear Detection of Drill Bit by Image-based Technique

    Science.gov (United States)

    Sukeri, Maziyah; Zulhilmi Paiz Ismadi, Mohd; Rahim Othman, Abdul; Kamaruddin, Shahrul

    2018-03-01

    Image processing for computer vision function plays an essential aspect in the manufacturing industries for the tool condition monitoring. This study proposes a dependable direct measurement method to measure the tool wear using image-based analysis. Segmentation and thresholding technique were used as the means to filter and convert the colour image to binary datasets. Then, the edge detection method was applied to characterize the edge of the drill bit. By using cross-correlation method, the edges of original and worn drill bits were correlated to each other. Cross-correlation graphs were able to detect the difference of the worn edge despite small difference between the graphs. Future development will focus on quantifying the worn profile as well as enhancing the sensitivity of the technique.

  13. Plagiarism detection and prevention techniques in engineering education

    OpenAIRE

    Halak, Basel; El-Hajjar, Mohammed

    2016-01-01

    Plagiarism seriously damages the education process in a number of ways; it prevents students from developing the skills of creative thinking and critical analysis; it undermines the trust between lectures and students, and if goes undetected, it can impact the reputation of the academic institution and devalue its degrees. In this paper, we present two techniques for plagiarism detection and prevention. The first method is based on the allocation of a unique assignment for each student, and t...

  14. Evaluation of neutron techniques for illicit substance detection

    International Nuclear Information System (INIS)

    Fink, C.L.; Micklich, B.J.; Yule, T.J.; Humm, P.; Sagalovsky, L.; Martin, M.M.

    1995-01-01

    We are studying inspection systems based on the use of fast neutrons for detecting illicit substances such as explosives and drugs in luggage and cargo containers. Fast-neutron techniques can determine the quantities of light elements such as carbon, nitrogen, and oxygen in a volume element. Illicit substances containing these elements are characterized by distinctive elemental densities or density ratios. We discuss modeling and tomographic reconstruction studies for fast-neutron transmission spectroscopy. (orig.)

  15. Evaluation of neutron techniques for illicit substance detection

    International Nuclear Information System (INIS)

    Fink, C.L.; Micklich, B.J.; Yule, T.J.; Humm, P.; Sagalovsky, L.; Martin, M.M.

    1994-01-01

    The authors are studying inspection systems based on the use of fast neutrons for detecting illicit substances such as explosives and drugs in luggage and cargo containers. Fast neutron techniques can determine the quantities of light elements such as carbon, nitrogen, and oxygen in a volume element. Illicit substances containing these elements are characterized by distinctive elemental densities or density ratios. They discuss modeling and tomographic reconstruction studies for fast-neutron transmission spectroscopy

  16. Infrared absorption of CH3OSO detected with time-resolved Fourier-transform spectroscopy.

    Science.gov (United States)

    Chen, Jin-Dah; Lee, Yuan-Pern

    2011-03-07

    A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to detect temporally resolved infrared absorption spectra of CH(3)OSO produced upon irradiation of a flowing gaseous mixture of CH(3)OS(O)Cl in N(2) or CO(2) at 248 nm. Two intense transient features with origins near 1152 and 994 cm(-1) are assigned to syn-CH(3)OSO; the former is attributed to overlapping bands at 1154 ± 3 and 1151 ± 3 cm(-1), assigned to the S=O stretching mixed with CH(3) rocking (ν(8)) and the S=O stretching mixed with CH(3) wagging (ν(9)) modes, respectively, and the latter to the C-O stretching (ν(10)) mode at 994 ± 6 cm(-1). Two weak bands at 2991 ± 6 and 2956 ± 3 cm(-1) are assigned as the CH(3) antisymmetric stretching (ν(2)) and symmetric stretching (ν(3)) modes, respectively. Observed vibrational transition wavenumbers agree satisfactorily with those predicted with quantum-chemical calculations at level B3P86∕aug-cc-pVTZ. Based on rotational parameters predicted at that level, the simulated rotational contours of these bands agree satisfactorily with experimental results. The simulation indicates that the S=O stretching mode of anti-CH(3)OSO near 1164 cm(-1) likely makes a small contribution to the observed band near 1152 cm(-1). A simple kinetic model of self-reaction is employed to account for the decay of CH(3)OSO and yields a second-order rate coefficient k=(4 ± 2)×10(-10) cm(3)molecule(-1)s(-1). © 2011 American Institute of Physics.

  17. Applications of pattern recognition techniques to online fault detection

    International Nuclear Information System (INIS)

    Singer, R.M.; Gross, K.C.; King, R.W.

    1993-01-01

    A common problem to operators of complex industrial systems is the early detection of incipient degradation of sensors and components in order to avoid unplanned outages, to orderly plan for anticipated maintenance activities and to assure continued safe operation. In such systems, there usually are a large number of sensors (upwards of several thousand is not uncommon) serving many functions, ranging from input to control systems, monitoring of safety parameters and component performance limits, system environmental conditions, etc. Although sensors deemed to measure important process conditions are generally alarmed, the alarm set points usually are just high-low limits and the operator's response to such alarms is based on written procedures and his or her experience and training. In many systems this approach has been successful, but in situations where the cost of a forced outage is high an improved method is needed. In such cases it is desirable, if not necessary, to detect disturbances in either sensors or the process prior to any actual failure that could either shut down the process or challenge any safety system that is present. Recent advances in various artificial intelligence techniques have provided the opportunity to perform such functions of early detection and diagnosis. In this paper, the experience gained through the application of several pattern-recognition techniques to the on-line monitoring and incipient disturbance detection of several coolant pumps and numerous sensors at the Experimental Breeder Reactor-II (EBR-II) which is located at the Idaho National Engineering Laboratory is presented

  18. A new imaging technique for detecting interstellar communications

    Science.gov (United States)

    Vallerga, John; Welsh, Barry; Kotze, Marissa; Siegmund, Oswald

    2017-01-01

    We report on a unique detection methodology using the Berkeley Visible Image Tube (BVIT) mounted on the 10m Southern African Large Telescope (SALT) to search for laser pulses originating in communications from advanced extraterrestrial (ET) civilizations residing on nearby Earth-like planets located within their habitability zones. The detection technique assumes that ET communicates through high powered pulsed lasers with pulse durations on the order of 5 nanoseconds, the signals thereby being brighter than that of the host star within this very short period of time. Our technique turns down the gain of the optically sensitive photon counting microchannel plate detector such that ~30 photons are required in a 5ns window to generate an imaged event. Picking a priori targets with planets in the habitable zone substantially reduces the false alarm rate. Interplanetary communication by optical masers was first postulated by Schwartz and Townes in 1961. Under the assumption that ET has access to a 10 m class telescope operated as a transmitter then we could detect lasers with a similar power to that of the Livermore Laboratory laser (~1.8Mj per pulse), to a distance of ~ 1000 pc. In this talk we present the results of 2400 seconds of BVIT observations on the SALT of the star Wolf 1061, which is known to harbor an Earth-sized exoplanet located in the habitability zone. At this distance (4.3 pc), BVIT on SALT could detect a 48 joule per pulse laser, now commercially available as tabletop devices.

  19. Detection of uranium enrichment activities using environmental monitoring techniques

    International Nuclear Information System (INIS)

    Belew, W.L.; Carter, J.A.; Smith, D.H.; Walker, R.L.

    1993-01-01

    Uranium enrichment processes have the capability of producing weapons-grade material in the form of highly enriched uranium. Thus, detection of undeclared uranium enrichment activities is an international safeguards concern. The uranium separation technologies currently in use employ UF 6 gas as a separation medium, and trace quantities of enriched uranium are inevitably released to the environment from these facilities. The isotopic content of uranium in the vegetation, soil, and water near the plant site will be altered by these releases and can provide a signature for detecting the presence of enriched uranium activities. This paper discusses environmental sampling and analytical procedures that have been used for the detection of uranium enrichment facilities and possible safeguards applications of these techniques

  20. Applications of some microscopic, diffraction and absorption techniques to the study of metal--hydrogen systems

    International Nuclear Information System (INIS)

    Pick, M.A.

    1979-01-01

    Several experimental techniques were reviewed which are used to investigate metal hydrogen systems. The first technique is metallography and optical microscopy. This is a very old technique which was found to be very powerful in the case of metal hydrogen systems. A few examples of such work are shown and the results are discussed

  1. Growth of nanocrystalline silicon thin film with layer-by-layer technique for fast photo-detecting applications

    International Nuclear Information System (INIS)

    Lin, C.-Y.; Fang, Y.-K.; Chen, S.-F.; Lin, P.-C.; Lin, C.-S.; Chou, T.-H; Hwang, J.S.; Lin, K.I.

    2006-01-01

    High mobility nanocrystalline silicon (nc-Si) films with layer-by-layer technique for fast photo-detecting applications were studied. The structure and morphology of films were studied by means of XRD, micro-Raman scattering, SEM and AFM. The Hall mobility and absorption properties have been investigated and found they were seriously affected by the number of layers in growing, i.e., with increasing of layer number, Hall mobility increased but absorption coefficient decreased. The optimum layer number of nc-Si films for fast near-IR photo-detecting is 7 with film thickness of 1400 nm, while that for fast visible photo-detecting is 17 with film thickness of 3400 nm

  2. Technique for rapid detection of phthalates in water and beverages

    KAUST Repository

    Zia, Asif I.

    2013-05-01

    The teratogenic and carcinogenic effects of phthalate esters on living beings are proven in toxicology studies. These ubiquitous food and environmental pollutants pose a great danger to the human race due to their extraordinary use as a plasticizer in the consumer product industry. Contemporary detection techniques used for phthalates require a high level of skills, expensive equipment and longer analysis time than the presented technique. Presented research work introduces a real time non-invasive detection technique using a new type of silicon substrate based planar interdigital (ID) sensor fabricated on basis of thin film micro-electromechanical system (MEMS) semiconductor device fabrication technology. Electrochemical impedance spectroscopy (EIS) was used in conjunction with the fabricated sensor to detect phthalates in deionized water. Various concentrations of di(2-ethylhexyl) phthalate (DEHP) as low as 2 ppb to a higher level of 2 ppm in deionized water were detected distinctively using new planar ID sensor based EIS sensing system. Dip testing method was used to obtain the conductance and dielectric properties of the bulk samples. Parylene C polymer coating was used as a passivation layer on the surface of the fabricated sensor to reduce the influence of Faradaic currents. In addition, inherent dielectric properties of the coating enhanced the sensitivity of the capacitive type sensor. Electrochemical spectrum analysis algorithm was used to model experimentally observed impedance spectrum to deduce constant phase element (CPE) equivalent circuit to analyse the kinetic processes taking place inside the electrochemical cell. Curve fitting technique was used to extract the values of the circuit components and explain experimental results on theoretical grounds. The sensor performance was tested by adding DEHP to an energy drink at concentrations above and below the minimal risk level (MRL) limit set by the ATSDR (Agency for Toxic Substances & Disease Registry

  3. Isotope Enrichment Detection by Laser Ablation - Laser Absorption Spectrometry: Automated Environmental Sampling and Laser-Based Analysis for HEU Detection

    International Nuclear Information System (INIS)

    Anheier, Norman C.; Bushaw, Bruce A.

    2010-01-01

    The global expansion of nuclear power, and consequently the uranium enrichment industry, requires the development of new safeguards technology to mitigate proliferation risks. Current enrichment monitoring instruments exist that provide only yes/no detection of highly enriched uranium (HEU) production. More accurate accountancy measurements are typically restricted to gamma-ray and weight measurements taken in cylinder storage yards. Analysis of environmental and cylinder content samples have much higher effectiveness, but this approach requires onsite sampling, shipping, and time-consuming laboratory analysis and reporting. Given that large modern gaseous centrifuge enrichment plants (GCEPs) can quickly produce a significant quantity (SQ ) of HEU, these limitations in verification suggest the need for more timely detection of potential facility misuse. The Pacific Northwest National Laboratory (PNNL) is developing an unattended safeguards instrument concept, combining continuous aerosol particulate collection with uranium isotope assay, to provide timely analysis of enrichment levels within low enriched uranium facilities. This approach is based on laser vaporization of aerosol particulate samples, followed by wavelength tuned laser diode spectroscopy to characterize the uranium isotopic ratio through subtle differences in atomic absorption wavelengths. Environmental sampling (ES) media from an integrated aerosol collector is introduced into a small, reduced pressure chamber, where a focused pulsed laser vaporizes material from a 10 to 20-(micro)m diameter spot of the surface of the sampling media. The plume of ejected material begins as high-temperature plasma that yields ions and atoms, as well as molecules and molecular ions. We concentrate on the plume of atomic vapor that remains after the plasma has expanded and then cooled by the surrounding cover gas. Tunable diode lasers are directed through this plume and each isotope is detected by monitoring absorbance

  4. 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.

  5. Hollow-core fiber sensing technique for pipeline leak detection

    Science.gov (United States)

    Challener, W. A.; Kasten, Matthias A.; Karp, Jason; Choudhury, Niloy

    2018-02-01

    Recently there has been increased interest on the part of federal and state regulators to detect and quantify emissions of methane, an important greenhouse gas, from various parts of the oil and gas infrastructure including well pads and pipelines. Pressure and/or flow anomalies are typically used to detect leaks along natural gas pipelines, but are generally very insensitive and subject to false alarms. We have developed a system to detect and localize methane leaks along gas pipelines that is an order of magnitude more sensitive by combining tunable diode laser spectroscopy (TDLAS) with conventional sensor tube technology. This technique can potentially localize leaks along pipelines up to 100 km lengths with an accuracy of +/-50 m or less. A sensor tube buried along the pipeline with a gas-permeable membrane collects leaking gas during a soak period. The leak plume within the tube is then carried to the nearest sensor node along the tube in a purge cycle. The time-to-detection is used to determine leak location. Multiple sensor nodes are situated along the pipeline to minimize the time to detection, and each node is composed of a short segment of hollow core fiber (HCF) into which leaking gas is transported quickly through a small pressure differential. The HCF sensing node is spliced to standard telecom solid core fiber which transports the laser light for spectroscopy to a remote interrogator. The interrogator is multiplexed across the sensor nodes to minimize equipment cost and complexity.

  6. Beam synchronous detection techniques for X-Ray spectroscopy

    International Nuclear Information System (INIS)

    Goujon, Gérard; Rogalev, Andreï; Goulon, José; Feite, Serge; Wilhelm, Fabrice

    2013-01-01

    The Photo diode detectors combine a set of properties that make them most appropriate, in particular, for X-ray Magnetic Circular Dichroism (XMCD) experiments. Under standard operating conditions, the detection bandwidth is primarily limited by the transimpedance preamplifier that converts the very low ac photocurrent into a voltage. On the other hand, when the photodiode is reverse biased, its finite shunt resistance will cause an undesirable, temperature dependent DC dark current. The best strategy to get rid of it is to use synchronous detection techniques. A classical implementation is based on the use of a chopper modulating the X-ray beam intensity at rather low frequencies (typically below 1 kHz). Here we report on the recent development of a fast Xray detection which has the capability to fully exploit the frequency structure of the ESRF X-ray beam (355 KHz and its harmonics). The availability of new wide band preamplifiers allowed us to extend the working frequency range up to a few MHz. A beam synchronous data processing was implemented in large FPGAs. Performances of the new detection system implemented at the ESRF beamline ID12 are illustrated with detection of the Fe K-edge XMCD spectra in garnets, using 4 bunches operation mode with modulation frequency of 1.4 MHz.

  7. A review of radioisotope techniques in the study of vitamin B12 absorption

    International Nuclear Information System (INIS)

    Boddy, K.

    1976-01-01

    The five in vivo tests in common use for the study of vitamin B 12 absorption, namely, 1) faecal excretion method, 2) urinary excretion method, 3) plasma radioactivity method, 4) hepatic uptake method, and 5) whole-body counting method, are described. The merits, disadvantages and limitations of each method are considered in a clinical context. Whole-body counting is regarded as the method of choice where appropriate facilities are available and when the delay of about 7 days in obtaining the result is acceptable. The plasma radioactivity method can provide concurrently a rapid assessment. (author)

  8. Detection of cavitation vortex in hydraulic turbines using acoustic techniques

    International Nuclear Information System (INIS)

    Candel, I; Ioana, C; Bunea, F; Politehnica University of Bucharest (Romania))" data-affiliation=" (Power Engineering Faculty, Politehnica University of Bucharest (Romania))" >Dunca, G; Politehnica University of Bucharest (Romania))" data-affiliation=" (Power Engineering Faculty, Politehnica University of Bucharest (Romania))" >Bucur, D M; Division Technique Générale, Grenoble (France))" data-affiliation=" (Electricité de France, Division Technique Générale, Grenoble (France))" >Reeb, B; Ciocan, G D

    2014-01-01

    Cavitation phenomena are known for their destructive capacity in hydraulic machineries and are caused by the pressure decrease followed by an implosion when the cavitation bubbles find an adverse pressure gradient. A helical vortex appears in the turbine diffuser cone at partial flow rate operation and can be cavitating in its core. Cavity volumes and vortex frequencies vary with the under-pressure level. If the vortex frequency comes close to one of the eigen frequencies of the turbine, a resonance phenomenon may occur, the unsteady fluctuations can be amplified and lead to important turbine and hydraulic circuit damage. Conventional cavitation vortex detection techniques are based on passive devices (pressure sensors or accelerometers). Limited sensor bandwidths and low frequency response limit the vortex detection and characterization information provided by the passive techniques. In order to go beyond these techniques and develop a new active one that will remove these drawbacks, previous work in the field has shown that techniques based on acoustic signals using adapted signal content to a particular hydraulic situation, can be more robust and accurate. The cavitation vortex effects in the water flow profile downstream hydraulic turbines runner are responsible for signal content modifications. Basic signal techniques use narrow band signals traveling inside the flow from an emitting transducer to a receiving one (active sensors). Emissions of wide band signals in the flow during the apparition and development of the vortex embeds changes in the received signals. Signal processing methods are used to estimate the cavitation apparition and evolution. Tests done in a reduced scale facility showed that due to the increasing flow rate, the signal -- vortex interaction is seen as modifications on the received signal's high order statistics and bandwidth. Wide band acoustic transducers have a higher dynamic range over mechanical elements; the system

  9. Application of tunable diode laser absorption spectroscopy in the detection of oxygen

    Science.gov (United States)

    Zhou, Xin; Jin, Xing

    2015-10-01

    Most aircrafts is driven by chemic energy which is released in the combustion process. For improving the capability of engine and controlling the running on-time, the processes of fuel physics and chemistry need to be analysis by kinds of high quality sensor. In the research of designing and improving the processes of fuel physics and chemistry, the concentration, temperature and velocity of kinds of gas in the combustor need to be detected and measured. In addition, these engines and research equipments are always in the harsh environment of high temperature, high pressure and high speed. The harsh environment needs the sensor to be high reliability, well repetition, no cross- sensitivity between gases, and the traditional measurement system can't satisfy the metrical requirement well. Tunable diode laser absorption spectroscopy (TDLAS) analytic measurement technology can well satisfy the measurement in the harsh environment, which can support the whole measurement plan and high quality measurement system. Because the TDLAS sensor has the excellence of small bulk, light weight, high reliability and well specifically measurement, the TDLAS measurement technology has wide prospects. Different from most measurements, only a beam of laser can be pass through the measured environment by TDLAS, and the measurement equipment needn't be set in the harsh environment. So, the TDLAS equipment can't be interrupted by the measured equipment. The ability of subsistence in the harsh environment is very valuable, especially in the measurement on the subject of aerospace with environment of high speed, combustion and plasma. This paper focuses on the collecting the articles on the subject of oxygen detection of TDLAS. By analyzing the research and results of the articles, we conclude the central issues, difficulties and results. And we can get some instructive conclusions.

  10. FEM Techniques for High Stress Detection in Accelerated Fatigue Simulation

    Science.gov (United States)

    Veltri, M.

    2016-09-01

    This work presents the theory and a numerical validation study in support to a novel method for a priori identification of fatigue critical regions, with the aim to accelerate durability design in large FEM problems. The investigation is placed in the context of modern full-body structural durability analysis, where a computationally intensive dynamic solution could be required to identify areas with potential for fatigue damage initiation. The early detection of fatigue critical areas can drive a simplification of the problem size, leading to sensible improvement in solution time and model handling while allowing processing of the critical areas in higher detail. The proposed technique is applied to a real life industrial case in a comparative assessment with established practices. Synthetic damage prediction quantification and visualization techniques allow for a quick and efficient comparison between methods, outlining potential application benefits and boundaries.

  11. Development of photo stimulated luminescence technique for detecting irradiated food

    International Nuclear Information System (INIS)

    Ros Anita Ahmad Ramli; Ahmad Zainuri Mohd Dzomir; Zainon Othman; Wan Saffiey Wan Abdullah

    2012-01-01

    The exposure of food to ionizing radiation is being progressively used in many countries to inactivate food pathogens, to eradicate pests and to extend shelf-life of food. To ensure free consumer choice, irradiated food will be labeled. The availability of a reliable method to detect irradiated food is important to enforce legal controls on labeling requirements, ensure proper distribution and increase consumer confidence. This paper reports on the preliminary application of photo stimulated luminescence technique (PSL) as a potential method to detect irradiated food and perhaps be used for monitoring irradiated food on sale locally in the near future. Thus this study will be beneficial and relevant for application of food irradiation towards improving food safety and security in Malaysia. (author)

  12. Development of Photostimulated Luminescence Technique for Detecting Irradiated Food

    International Nuclear Information System (INIS)

    Ros Anita Ahmad Ramli; Ahmad Zainuri Mohd Dzomir; Zainon Othman; Wan Saffiey Wan Abdullah; Muhamad Samudi Yasir

    2015-01-01

    The exposure of food to ionizing radiation is being progressively used in many countries to inactivate food pathogens, to eradicate pests and to extend shelf-life of food. To ensure free consumer choice, irradiated food will be labeled. The availability of a reliable method to detect irradiated food is important to enforce legal controls on labeling requirements, ensure proper distribution and increase consumer confidence. This paper reports on the preliminary application of photostimulated luminescence technique (PSL) as a potential method to detect irradiated food and perhaps be used for monitoring irradiated food on sale locally in the near future. Thus this study will be beneficial and relevant for application of food irradiation towards improving food safety and security in Malaysia. (author)

  13. DNA microarray technique for detecting food-borne pathogens

    Directory of Open Access Journals (Sweden)

    Xing GAO

    2012-08-01

    Full Text Available Objective To study the application of DNA microarray technique for screening and identifying multiple food-borne pathogens. Methods The oligonucleotide probes were designed by Clustal X and Oligo 6.0 at the conserved regions of specific genes of multiple food-borne pathogens, and then were validated by bioinformatic analyses. The 5' end of each probe was modified by amino-group and 10 Poly-T, and the optimized probes were synthesized and spotted on aldehyde-coated slides. The bacteria DNA template incubated with Klenow enzyme was amplified by arbitrarily primed PCR, and PCR products incorporated into Aminoallyl-dUTP were coupled with fluorescent dye. After hybridization of the purified PCR products with DNA microarray, the hybridization image and fluorescence intensity analysis was acquired by ScanArray and GenePix Pro 5.1 software. A series of detection conditions such as arbitrarily primed PCR and microarray hybridization were optimized. The specificity of this approach was evaluated by 16 different bacteria DNA, and the sensitivity and reproducibility were verified by 4 food-borne pathogens DNA. The samples of multiple bacteria DNA and simulated water samples of Shigella dysenteriae were detected. Results Nine different food-borne bacteria were successfully discriminated under the same condition. The sensitivity of genomic DNA was 102 -103pg/ μl, and the coefficient of variation (CV of the reproducibility of assay was less than 15%. The corresponding specific hybridization maps of the multiple bacteria DNA samples were obtained, and the detection limit of simulated water sample of Shigella dysenteriae was 3.54×105cfu/ml. Conclusions The DNA microarray detection system based on arbitrarily primed PCR can be employed for effective detection of multiple food-borne pathogens, and this assay may offer a new method for high-throughput platform for detecting bacteria.

  14. Radiotracer technique for leakage detection under simulated conditions

    International Nuclear Information System (INIS)

    Yelgaonkar, V.N.; Sharma, V.K.; Tapase, A.S.

    2001-01-01

    Radiotracer techniques are often used to locate leaks in underground pipelines. An attempt was made to standardize radiotracer pulse migration in terms of minimum detectable limit. For this purpose a 6 inch diameter 1200 long steel pipe was used. Two leak rates viz. 10 litres per minute and 1 litre per minute with an accuracy of ± 10% were simulated. The experiments on this pipeline showed that this method could be used to locate a leak of the order of 1 litre per minute in a 6 inch diameter isolated underground pipeline. (author)

  15. Quantum cascade laser absorption spectroscopy with the amplitude-to-time conversion technique for atmospheric-pressure plasmas

    International Nuclear Information System (INIS)

    Yumii, Takayoshi; Kimura, Noriaki; Hamaguchi, Satoshi

    2013-01-01

    The NO 2 concentration, i.e., density, in a small plasma of a nitrogen oxide (NOx) treatment reactor has been measured by highly sensitive laser absorption spectroscopy. The absorption spectroscopy uses a single path of a quantum cascade laser beam passing through a plasma whose dimension is about 1 cm. The high sensitivity of spectroscopy is achieved by the amplitude-to-time conversion technique. Although the plasma reactor is designed to convert NO in the input gas to NO 2 , it has been demonstrated by this highly sensitive absorption spectroscopy that NO 2 in a simulated exhaust gas that enters the reactor is decomposed by the plasma first and then NO 2 is formed again, possibly more than it was decomposed, through a series of gas-phase reactions by the time the gas exits the reactor. The observation is consistent with that of an earlier study on NO decomposition by the same type of a plasma reactor [T. Yumii et al., J. Phys. D 46, 135202 (2013)], in which a high concentration of NO 2 was observed at the exit of the reactor.

  16. Validation of phenol red versus gravimetric method for water reabsorption correction and study of gender differences in Doluisio's absorption technique.

    Science.gov (United States)

    Tuğcu-Demiröz, Fatmanur; Gonzalez-Alvarez, Isabel; Gonzalez-Alvarez, Marta; Bermejo, Marival

    2014-10-01

    The aim of the present study was to develop a method for water flux reabsorption measurement in Doluisio's Perfusion Technique based on the use of phenol red as a non-absorbable marker and to validate it by comparison with gravimetric procedure. The compounds selected for the study were metoprolol, atenolol, cimetidine and cefadroxil in order to include low, intermediate and high permeability drugs absorbed by passive diffusion and by carrier mediated mechanism. The intestinal permeabilities (Peff) of the drugs were obtained in male and female Wistar rats and calculated using both methods of water flux correction. The absorption rate coefficients of all the assayed compounds did not show statistically significant differences between male and female rats consequently all the individual values were combined to compare between reabsorption methods. The absorption rate coefficients and permeability values did not show statistically significant differences between the two strategies of concentration correction. The apparent zero order water absorption coefficients were also similar in both correction procedures. In conclusion gravimetric and phenol red method for water reabsorption correction are accurate and interchangeable for permeability estimation in closed loop perfusion method. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Mode of the absorption of water and nutrients by ascocarps of Tuber melanosporum and Tuber aestivum: a radioactive tracer technique

    International Nuclear Information System (INIS)

    Barry, D.; Staunton, S.; Callot, G.

    1994-01-01

    A simple technique has been developed to study the absorption capacity of the tufts of mycelial filaments, or hyphae, observed on both black and white truffles Tuber melanosporum and Tuber aestivum. These hyphae sprout from the tops of certain scales on the peridium of Tuber. They colonize the surrounding soil and could therefore exploit the nutrients from a large volume of soil. The ability to absorb organic and inorganic nutrients from a source other than the host is a necessary condition for the hypothesis we wished to test, namely that at some stage in its development the truffle ascocarp becomes autonomous. The absorption was demonstrated using autoradiography and liquid scintillation counting. We found that the tufts of hyphae are water permeable ( 3 H 2 O). In addition, they absorb a sugar ([ 14 C]mannose) and an anion ([ 32 P]phosphate). An analysis of our results shows that the spatial distribution of [ 32 P]phosphate is independent of that of tritiated water; the transport of phosphate is therefore not determined by water flux. The quantity and redistribution of the tracer depended on the application site, directly onto the peridium or on a mycelial tuft. The tufts increase the absorption of the tracer and influence its internal redistribution towards accumulation zones. (author)

  18. Cyanotoxins: Which detection technique for an optimum risk assessment?

    Science.gov (United States)

    Gaget, Virginie; Lau, Melody; Sendall, Barbara; Froscio, Suzanne; Humpage, Andrew R

    2017-07-01

    The presence of toxigenic cyanobacteria (blue-green algae) in drinking water reservoirs poses a risk to human and animal health worldwide. Guidelines and health alert levels have been issued in the Australian Drinking Water Guidelines for three major toxins, which are therefore the subject of routine monitoring: microcystin, cylindrospermopsin and saxitoxin. While it is agreed that these toxic compounds should be monitored closely, the routine surveillance of these bioactive chemicals can be done in various ways and deciding which technique to use can therefore be challenging. This study compared several assays available for the detection of these toxins and their producers in environmental samples: microscopy (for identification and enumeration of cyanobacteria), ELISA (Enzyme-Linked ImmunoSorbant Assay), PPIA (Protein phosphatase inhibition assay), PSI (Protein synthesis inhibition), chemical analysis and PCR (Polymerase Chain Reaction). Results showed that there was generally a good correlation between the presence of potentially toxigenic cyanobacteria and the detection of the toxin by ELISA. Nevertheless data suggest that cell numbers and toxin concentrations measured in bioassays do not necessarily correlate and that enumeration of potentially toxic cyanobacteria by microscopy, while commonly used for monitoring and risk assessment, is not the best indicator of real toxin exposure. The concentrations of saxitoxins quantified by ELISA were significantly different than those measured by LC-MS, while results were comparable in both assays for microcystin and cylindrospermopsin. The evaluation of these analytical methods led to the conclusion that there is no "gold standard" technique for the detection of the aforementioned cyanotoxins but that the choice of detection assay depends on cost, practicality, reliability and comparability of results and essentially on the question to be answered, notably on toxin exposure potential. Copyright © 2017 Elsevier Ltd. All

  19. DETECTING THE WARM-HOT INTERGALACTIC MEDIUM THROUGH X-RAY ABSORPTION LINES

    Energy Technology Data Exchange (ETDEWEB)

    Yao Yangsen; Shull, J. Michael; Cash, Webster [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Wang, Q. Daniel, E-mail: yaoys@colorado.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2012-02-20

    The warm-hot intergalactic medium (WHIM) at temperatures 10{sup 5}-10{sup 7} K is believed to contain 30%-50% of the baryons in the local universe. However, all current X-ray detections of the WHIM at redshifts z > 0 are of low statistical significance ({approx}< 3{sigma}) and/or controversial. In this work, we aim to establish the detection limits of current X-ray observatories and explore requirements for next-generation X-ray telescopes for studying the WHIM through X-ray absorption lines. We analyze all available grating observations of Mrk 421 and obtain spectra with signal-to-noise ratios (S/Ns) of {approx}90 and 190 per 50 mA spectral bin from Chandra and XMM-Newton observations, respectively. Although these spectra are two of the best ever collected with Chandra and XMM-Newton, we cannot confirm the two WHIM systems reported by Nicastro et al. in 2005. Our bootstrap simulations indicate that spectra with such high S/N cannot constrain the WHIM with O VII column densities N{sub Ovii}{approx}10{sup 15} cm{sup -2} (corresponding to an equivalent width of 2.5 mA for a Doppler velocity of 50 km s{sup -1}) at {approx}> 3{sigma} significance level. The simulation results also suggest that it would take >60 Ms for Chandra and 140 Ms for XMM-Newton to measure the N{sub Ovii} at {>=}4{sigma} from a spectrum of a background QSO with flux of {approx}0.2 mCrab (1 Crab = 2 Multiplication-Sign 10{sup -8} erg s{sup -1} cm{sup -2} at 0.5-2 keV). Future X-ray spectrographs need to be equipped with spectral resolution R {approx} 4000 and effective area A {>=} 100 cm{sup 2} to accomplish the similar constraints with an exposure time of {approx}2 Ms and would require {approx}11 Ms to survey the 15 QSOs with flux {approx}> 0.2 mCrab along which clear intergalactic O VI absorbers have been detected.

  20. Damage detection in wind turbine blades using acoustic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Juengert, A., E-mail: anne.juengert@mpa.uni-stuttgart.de [Univ. of Stuttgart, Materialpruefungsanstalt Stuttgart, Stuttgart (Germany)

    2013-05-15

    Facing climate change, the use of renewable energy gains importance. The wind energy sector grows very fast. Bigger and more powerful wind turbines will be built in the coming decades and the safety and reliability of the turbines will become more important. Wind turbine blades have to be inspected at regular intervals, because they are highly stressed during operation and a blade breakdown can cause big economic damages. The turbine blades consist of fiber reinforced plastics (GFRP/CFRP) and sandwich areas containing wood or plastic foam. The blades are manufactured as two halves and glued together afterwards. Typical damages are delaminations within the GFRP or the sandwich and missing adhesive or deficient bond at the bonding surfaces. The regular inspections of wind turbine blades are performed manually by experts and are limited to visual appraisals and simple tapping tests. To improve the inspections of wind turbine blades non-destructive testing techniques using acoustic waves are being developed. To detect delaminations within the laminates of the turbine blade, a local resonance spectroscopy was used. To detect missing bond areas from the outside of the blade the impulse-echo-technique was applied. This paper is an updated reprint of an article published on ndt.net in 2008. (author)

  1. Damage detection in wind turbine blades using acoustic techniques

    International Nuclear Information System (INIS)

    Juengert, A.

    2013-01-01

    Facing climate change, the use of renewable energy gains importance. The wind energy sector grows very fast. Bigger and more powerful wind turbines will be built in the coming decades and the safety and reliability of the turbines will become more important. Wind turbine blades have to be inspected at regular intervals, because they are highly stressed during operation and a blade breakdown can cause big economic damages. The turbine blades consist of fiber reinforced plastics (GFRP/CFRP) and sandwich areas containing wood or plastic foam. The blades are manufactured as two halves and glued together afterwards. Typical damages are delaminations within the GFRP or the sandwich and missing adhesive or deficient bond at the bonding surfaces. The regular inspections of wind turbine blades are performed manually by experts and are limited to visual appraisals and simple tapping tests. To improve the inspections of wind turbine blades non-destructive testing techniques using acoustic waves are being developed. To detect delaminations within the laminates of the turbine blade, a local resonance spectroscopy was used. To detect missing bond areas from the outside of the blade the impulse-echo-technique was applied. This paper is an updated reprint of an article published on ndt.net in 2008. (author)

  2. Study of capillary absorption kinetics by X-ray CT imaging techniques: a survey on sedimentary rocks of Sicily

    Directory of Open Access Journals (Sweden)

    Tiziano Schillaci

    2008-04-01

    Full Text Available Sedimentary rocks are natural porous materials with a great percent of microscopic interconnected pores: they contain fluids, permitting their movement on macroscopic scale. Generally, these rocks present porosity higher then metamorphic rocks. Under certain points of view, this feature represents an advantage; on the other hand, this can constitute an obstacle for cultural heritage applications, because the porosity grade can lead to a deterioration of the lapideous monument for water capillary absorption. In this paper, CT (Computerized Tomography image techniques are applied to capillary absorption kinetics in sedimentary rocks utilized for the Greek temples as well as baroc monuments, respectively located in western and southeastern Sicily. Rocks were sampled near the archaeological areas of Agrigento, Segesta, Selinunte and Val di Noto. CT images were acquired at different times, before and after the water contact, using image elaboration techniques during the acquisition as well as the post-processing phases. Water distribution into porous spaces has been evaluated on the basis of the Hounsfield number, estimated for the 3-D voxel structure of samples. For most of the considered samples, assumptions based on Handy model permit to correlate the average height of the wetting front to the square root of time. Stochastic equations were introduced in order to describe the percolative water behavior in heterogeneous samples, as the Agrigento one. Before the CT acquisition, an estimate of the capillary absorption kinetics has been carried out by the gravimetric method. A petrographical characterization of samples has been performed by stereomicroscope observations, while porosity and morphology of porous have been surveyed by SEM (Scanning Electron Microscope images. Furthermore, the proposed methods have also permitted to define penetration depth as well as distribution uniformity of materials used for restoration and conservation of historical

  3. Study of new technique of solid combustible materials to determination of volatile elements by flame atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Campos, R.C. de.

    1988-01-01

    A new technique for direct trace element analysis of solid combustible materials is described. The samples (up to 10 mg) are weighed on a graphite platform wich is then placed in a quartz tube, at the focal point of three infrared lamps. When the lamps are turned on, the sample burns in a stream of air, and the resulting dry aerosol containing volatile elements such as Hg, Cd, Bi, Tl, Zn, Pb and Cu is carried into the mixing chamber and thence into the flame, where the atomic absorption measurement is carried out. This technique overcomes chemical sample preparation steps, avoiding contaminations of losses associated with these steps. A ''furnace in flame'' system where the aerosol is transported to a flame heated T-tube is also described. The influence of flame stoichiometry, observation height, platform material and air flux intensity was studied inorder to determine optimal analytical conditions. (author) [pt

  4. Colloidal silver nanoparticles prepared by UV-light induced citrate reduction technique for the quantitative detection of uric acid

    Science.gov (United States)

    Maity, Anupam; Panda, Sovan Kumar

    2018-04-01

    Reddish-yellow color colloid consisting of silver nanoparticles (Ag NPs) has been synthesized by reducing aqueous AgNO3 solution by photo-induced citrate reduction technique under UV light. As prepared colloid exhibits single and intense plasmonic absorption peak in the violet region of the visible spectra with the peak centered at 405 nm. The NPs are fine and spherical with diameter ranging from 5 to 10 nm. These colloidal NPs have been used for the quantitative detection of uric acid by UV-VIS spectroscopy. A linear red shifting of the characteristics Plasmonic absorption peak of Ag NPs is observed with uric acid concentration. Uric acid can be detected by UV-VIS spectroscopy down to 5 nM limit using the prepared colloid.

  5. Pre-Saturation Technique of the Recycled Aggregates: Solution to the Water Absorption Drawback in the Recycled Concrete Manufacture.

    Science.gov (United States)

    García-González, Julia; Rodríguez-Robles, Desirée; Juan-Valdés, Andrés; Morán-Del Pozo, Julia Mª; Guerra-Romero, M Ignacio

    2014-09-01

    The replacement of natural aggregates by recycled aggregates in the concrete manufacturing has been spreading worldwide as a recycling method to counteract the large amount of construction and demolition waste. Although legislation in this field is still not well developed, many investigations demonstrate the possibilities of success of this trend given that concrete with satisfactory mechanical and durability properties could be achieved. However, recycled aggregates present a low quality compared to natural aggregates, the water absorption being their main drawback. When used untreated in concrete mix, the recycled aggregate absorb part of the water initially calculated for the cement hydration, which will adversely affect some characteristics of the recycled concrete. This article seeks to demonstrate that the technique of pre-saturation is able to solve the aforementioned problem. In order to do so, the water absorption of the aggregates was tested to determine the necessary period of soaking to bring the recycled aggregates into a state of suitable humidity for their incorporation into the mixture. Moreover, several concrete mixes were made with different replacement percentages of natural aggregate and various periods of pre-saturation. The consistency and compressive strength of the concrete mixes were tested to verify the feasibility of the proposed technique.

  6. Pre-Saturation Technique of the Recycled Aggregates: Solution to the Water Absorption Drawback in the Recycled Concrete Manufacture †

    Science.gov (United States)

    García-González, Julia; Rodríguez-Robles, Desirée; Juan-Valdés, Andrés; Morán-del Pozo, Julia Mª; Guerra-Romero, M. Ignacio

    2014-01-01

    The replacement of natural aggregates by recycled aggregates in the concrete manufacturing has been spreading worldwide as a recycling method to counteract the large amount of construction and demolition waste. Although legislation in this field is still not well developed, many investigations demonstrate the possibilities of success of this trend given that concrete with satisfactory mechanical and durability properties could be achieved. However, recycled aggregates present a low quality compared to natural aggregates, the water absorption being their main drawback. When used untreated in concrete mix, the recycled aggregate absorb part of the water initially calculated for the cement hydration, which will adversely affect some characteristics of the recycled concrete. This article seeks to demonstrate that the technique of pre-saturation is able to solve the aforementioned problem. In order to do so, the water absorption of the aggregates was tested to determine the necessary period of soaking to bring the recycled aggregates into a state of suitable humidity for their incorporation into the mixture. Moreover, several concrete mixes were made with different replacement percentages of natural aggregate and various periods of pre-saturation. The consistency and compressive strength of the concrete mixes were tested to verify the feasibility of the proposed technique. PMID:28788188

  7. One-step fabrication of submicrostructures by low one-photon absorption direct laser writing technique with local thermal effect

    Science.gov (United States)

    Nguyen, Dam Thuy Trang; Tong, Quang Cong; Ledoux-Rak, Isabelle; Lai, Ngoc Diep

    2016-01-01

    In this work, local thermal effect induced by a continuous-wave laser has been investigated and exploited to optimize the low one-photon absorption (LOPA) direct laser writing (DLW) technique for fabrication of polymer-based microstructures. It was demonstrated that the temperature of excited SU8 photoresist at the focusing area increases to above 100 °C due to high excitation intensity and becomes stable at that temperature thanks to the use of a continuous-wave laser at 532 nm-wavelength. This optically induced thermal effect immediately completes the crosslinking process at the photopolymerized region, allowing obtain desired structures without using the conventional post-exposure bake (PEB) step, which is usually realized after the exposure. Theoretical calculation of the temperature distribution induced by local optical excitation using finite element method confirmed the experimental results. LOPA-based DLW technique combined with optically induced thermal effect (local PEB) shows great advantages over the traditional PEB, such as simple, short fabrication time, high resolution. In particular, it allowed the overcoming of the accumulation effect inherently existed in optical lithography by one-photon absorption process, resulting in small and uniform structures with very short lattice constant.

  8. The use of tissue culture techniques to detect irradiated vegetables

    International Nuclear Information System (INIS)

    Al-Safadi, B.; Sharabi, N.E.; Nabulsi, I

    2001-01-01

    the ability of two tissue culture methods, callus and vegetable growth induction, to detect irradiated vegetables was evaluated. Potato tubers, carrot roots, garlic cloves and onion bulbs were subjected to various gamma radiation doses (0, 25, 100, 150, 250, 500, 750, and 1000 Gy). Irradiated vegetables were cultured in vitro and in vivo (pots). Gamma irradiation significantly reduced callus-forming ability especially in carrot and potato where no callus was observed in doses higher than 50 Gy. Length of shoots and roots growing from irradiated garlic and onion explants was considerably reduced starting from the 25 Gy dose. No roots were formed on garlic explants at any irradiation dose. Garlic leaves growing from irradiated explants were spotted with purple to brown spots. The intensity of these spots increased as gamma ray dosage increased. In the pot experiment, potato plant appeared in the control only. On the contrary, a complete sprouting of garlic and onion was seen in all irradiation treatments. It was not possible to distinguish between the various irradiation treatments and the control 3 days after planting in pots. The two in vitro techniques, tested in our study, may effectively be used to detect irradiated vegetables and estimate the range of doses used. The callus formation method is more useful for potato and carrot, since regeneration of shoots in vitro from these two plants takes along time, making this method unpractical. The other technique is very useful in the case of onion and garlic since it is rapid. The two techniques can be used with most of the vegetables that can be cultured in vitro. (Author)

  9. 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.

  10. Aircraft applications of fault detection and isolation techniques

    Science.gov (United States)

    Marcos Esteban, Andres

    In this thesis the problems of fault detection & isolation and fault tolerant systems are studied from the perspective of LTI frequency-domain, model-based techniques. Emphasis is placed on the applicability of these LTI techniques to nonlinear models, especially to aerospace systems. Two applications of Hinfinity LTI fault diagnosis are given using an open-loop (no controller) design approach: one for the longitudinal motion of a Boeing 747-100/200 aircraft, the other for a turbofan jet engine. An algorithm formalizing a robust identification approach based on model validation ideas is also given and applied to the previous jet engine. A general linear fractional transformation formulation is given in terms of the Youla and Dual Youla parameterizations for the integrated (control and diagnosis filter) approach. This formulation provides better insight into the trade-off between the control and the diagnosis objectives. It also provides the basic groundwork towards the development of nested schemes for the integrated approach. These nested structures allow iterative improvements on the control/filter Youla parameters based on successive identification of the system uncertainty (as given by the Dual Youla parameter). The thesis concludes with an application of Hinfinity LTI techniques to the integrated design for the longitudinal motion of the previous Boeing 747-100/200 model.

  11. Detection of localized damage by eddy currents technique

    Directory of Open Access Journals (Sweden)

    Aoukili A.

    2014-01-01

    Full Text Available Non destructive evaluation techniques based on eddy currents (EC are largely used for quality control of the castings in a lot of industries. The principle of detection by EC consists in using an adequate inductive coil to generate them by a variable magnetic field, and measuring their effects by using one or several sensors. These effects result from the interaction between the induced magnetic field and the excited conductive material. A local variation of the physical properties or geometry of the tested sample, due to a singularity or a flaw, causes a modification of the EC distribution, enabling thus detection. In order to optimize the capacity of defect revealing by means of EC based probes, an accurate modelling of the problem is essential. This can be used to perform simulation of the EC distribution under different circumstances and to analyze the EC sensitivity to the various implicated parameters. In this work, the modelling of EC is made by using the finite element method. Using a B-scan strategy was used, detection of a small defect having the shape of an open cavity is shown to be correctly indicated via monitoring variations of the induced voltage in the receiver coil.

  12. A new technique for detection of dynamic crack initiation

    International Nuclear Information System (INIS)

    Miya, K.; Yanagi, H.; Someya, K.

    1986-01-01

    A new test device was constructed to measure dynamic fracture toughness using electromagnetic force as a dynamic load and a laser system for the detection of load-line deflection. This method provides several advantages with respect to load control, high strain rate and easy instrumentation of the test device. Using the device, experiments on the dynamic fracture were performed with use of edge-cracked three point bending specimens which were made from the nuclear pressure vessel material A508cl.3. The present paper reports on the characteristic feature of dynamic fracture, the measuring technique of dynamic loading and deflection, the detection of dynamic crack initiation and fractographic observation. The detection of the dynamic crack initiation was made possible by the application of an AC electrical potential method that employs a lock-in amplifier driven by a demodulation mode of signal averager and guarantees a fast response to the crack initiation. It was found that the fracture was initiated after unloading of the electromagnetic force is finished, in other words, the fracture was caused by an inertia force and the dynamic fracture toughness Jsub(Id) of the test material was elevated with the increasing loading rate. (orig.)

  13. Mass Spectrometric C-14 Detection Techniques: Progress Report

    Science.gov (United States)

    Synal, H.

    2013-12-01

    Accelerator Mass Spectrometry (AMS) has been established as the best-suited radiocarbon detection technique. In the past years, significant progress with AMS instrumentation has been made resulting in a boom of new AMS facilities around the World. Today, carbon only AMS systems predominantly utilize 1+ charge state and molecule destruction in multiple ion gas collisions in stripper gas cell. This has made possible a significant simplification of the instruments, a reduction of ion energies and related to this less required space of the installations. However, state-of-the-art AMS instruments have still not reached a development stage where they can be regarded as table-top systems. In this respect, more development is needed to further advance the applicability of radiocarbon not only in the traditional fields of dating but also in biomedical research and new fields in Earth and environmental sciences. In a the proof-of-principle experiment the feasibility of radiocarbon detection over the entire range of dating applications was demonstrated using a pure mass spectrometer and ion energies below 50 keV. Now an experimental platform has been completed to test performance and to explore operation and measurement conditions of pure mass spectrometric radiocarbon detection. This contribution will overview the physical principles, which make this development possible and discuss key parameters of the instrumental design and performance of such an instrument.

  14. Vibration-rotational overtones absorption of solid hydrogens using optoacoustic spectroscopy technique

    International Nuclear Information System (INIS)

    Vieira, M.M.F.

    1985-01-01

    Vibrational-rotational overtones absorption solid hydrogens (H 2 , D 2 , HD) is studied using pulsed laser piezoeletric transducer (PULPIT) optoacoustic spectroscopy is studied. A general downward shift in energy from isolated molecular energies is observed. Studying normal-hydrogen it was observed that the phonon excitations associated with double-molecular transitions are predominantly transverse-optical phonons, whereas the excitations associated with single-molecular transitions are predominantly longitudinal - optical phonons. Multiplet structures were observed for certain double transitions in parahydrogen and orthodeuterium. The HD spectrum, besides presenting the sharp zero-phonon lines and the associated phonon side bands, like H 2 and D 2 , showed also two different features. This observation was common to all the transitions involving pure rotational excitation in H 2 and D 2 , which showed broad linewidths. This, together with some other facts (fluorescence lifetime *approx*10 5 sec; weak internal vibration and lattice coupling), led to the proposition of a mechanism for the fast nonradiative relaxation in solid hydrogens, implied from some observed experimental evidences. This relaxation, due to strong coupling, would happen in two steps: the internal vibration modes would relax to the rotational modes of the molecules, and then this rotational modes would relax to the lattice vibration modes. (Author) [pt

  15. Screening Technique for Lead and Cadmium in Toys and Other Materials Using Atomic Absorption Spectroscopy

    Science.gov (United States)

    Brouwer, Henry

    2005-01-01

    A simple procedure to quickly screen different consumer products for the presence of lead, cadmium, and other metals is described. This screening technique avoids expending a lot of preparation time on samples known to contain low levels of hazardous metals where only samples testing positive for the desired elements need to be analyzed…

  16. Quantitative Detection of Singlet O2 by Cavity-Enhanced Absorption

    National Research Council Canada - National Science Library

    Williams, Skip; Gupta, Manish; Owano, Thomas; Baer, Douglas S; O'Keefe, Anthony; Yarkony, David R; Matsika, Spiridoula

    2004-01-01

    .... The method is based on sensitive off-axis integrated-cavity-output spectroscopy (ICOS). Off-axis ICOS allows narrowband, continuous-wave lasers to be used in conjunction with optical cavities to record sensitive absorption measurements...

  17. GMRT Detection of HI 21 cm Associated Absorption towards the z ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Comparison of the radio and deep optical images .... Astronomical Image Processing System (AIPS) following standard procedures. About .... exhibits an HI absorption spectrum similar to that seen in 3C 190, viz., a broad shallow feature and ...

  18. 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.

  19. Column carbon dioxide and water vapor measurements by an airborne triple-pulse integrated path differential absorption lidar: novel lidar technologies and techniques with path to space

    Science.gov (United States)

    Singh, U. N.; Petros, M.; Refaat, T. F.; Yu, J.; Ismail, S.

    2017-09-01

    The 2-micron wavelength region is suitable for atmospheric carbon dioxide (CO2) measurements due to the existence of distinct absorption features for the gas at this wavelength region [1]. For more than 20 years, researchers at NASA Langley Research Center (LaRC) have developed several high-energy and high repetition rate 2-micron pulsed lasers [2]. Currently, LaRC team is engaged in designing, developing and demonstrating a triple-pulsed 2-micron direct detection Integrated Path Differential Absorption (IPDA) lidar to measure the weighted-average column dry-air mixing ratios of carbon dioxide (XCO2) and water vapor (XH2O) from an airborne platform [1, 3-5]. This novel technique allows measurement of the two most dominant greenhouse gases, simultaneously and independently, using a single instrument. This paper will provide status and details of the development of this airborne 2-micron triple-pulse IPDA lidar. The presented work will focus on the advancement of critical IPDA lidar components. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver and detector upgrades, laser packaging and lidar integration. Future plans for IPDA lidar ground integration, testing and flight validation will also be discussed. This work enables new Earth observation measurements, while reducing risk, cost, size, volume, mass and development time of required instruments.

  20. Ammonia detection using hollow waveguide enhanced laser absorption spectroscopy based on a 9.56 μm quantum cascade laser

    Science.gov (United States)

    Li, Jinyi; Yang, Sen; Wang, Ruixue; Du, Zhenhui; Wei, Yingying

    2017-10-01

    Ammonia (NH3) is the most abundant alkalescency trace gas in the atmosphere having a foul odor, which is produced by both natural and anthropogenic sources. Chinese Emission Standard for Odor Pollutants has listed NH3 as one of the eight malodorous pollutants since 1993, specifying the emission concentration less than 1 mg/m3 (1.44ppmv). NH3 detection continuously from ppb to ppm levels is significant for protection of environmental atmosphere and safety of industrial and agricultural production. Tunable laser absorption spectroscopy (TLAS) is an increasingly important optical method for trace gas detection. TLAS do not require pretreatment and accumulation of the concentration of the analyzed sample, unlike, for example, more conventional methods such as mass spectrometry or gas chromatography. In addition, TLAS can provide high precision remote sensing capabilities, high sensitivities and fast response. Hollow waveguide (HWG) has recently emerged as a novel concept serving as an efficient optical waveguide and as a highly miniaturized gas cell. Among the main advantages of HWG gas cell compared with conventional multi-pass gas cells is the considerably decreased sample which facilitates gas exchanging. An ammonia sensor based on TLAS using a 5m HWG as the gas cell is report here. A 9.56μm, continuous-wave, distributed feed-back (DFB), room temperature quantum cascade laser (QCL), is employed as the optical source. The interference-free NH3 absorption line located at 1046.4cm-1 (λ 9556.6nm) is selected for detection by analyzing absorption spectrum from 1045-1047 cm-1 within the ν2 fundamental absorption band of ammonia. Direct absorption spectroscopy (DAS) technique is utilized and the measured spectral line is fitted by a simulation model by HITRAN database to obtain the NH3 concentration. The sensor performance is tested with standard gas and the result shows a 1σ minimum detectable concentration of ammonia is about 200 ppb with 1 sec time resolution

  1. Interference-free mid-IR laser absorption detection of methane

    International Nuclear Information System (INIS)

    Pyun, Sung Hyun; Cho, Jungwan; Davidson, David F; Hanson, Ronald K

    2011-01-01

    A novel, mid-IR scanned-wavelength laser absorption diagnostic was developed for time-resolved, interference-free, absorption measurement of methane concentration. A differential absorption (peak minus valley) scheme was used that takes advantage of the structural differences of the absorption spectrum of methane and other hydrocarbons. A peak and valley wavelength pair was selected to maximize the differential cross-section (σ peak minus valley ) of methane for the maximum signal-to-noise ratio, and to minimize that of the interfering absorbers. Methane cross-sections at the peak and valley wavelengths were measured over a range of temperatures, 1000 to 2000 K, and pressures 1.3 to 5.4 atm. The cross-sections of the interfering absorbers were assumed constant over the small wavelength interval between the methane peak and valley features. Using this diagnostic, methane concentration time histories during n-heptane pyrolysis were measured behind reflected shock waves in a shock tube. The differential absorption scheme efficiently rejected the absorption interference and successfully recovered the vapor-phase methane concentration. These measurements allowed the comparison with methane concentration time-history simulations derived from a current n-heptane reaction mechanism (Sirjean et al 2009 A high-temperature chemical kinetic model of n-alkane oxidation JetSurF version 1.0)

  2. A differential absorption technique to estimate atmospheric total water vapor amounts

    Science.gov (United States)

    Frouin, Robert; Middleton, Elizabeth

    1990-01-01

    Vertically integrated water-vapor amounts can be remotely determined by measuring the solar radiance reflected by the earth's surface with satellites or aircraft-based instruments. The technique is based on the method by Fowle (1912, 1913) and utilizes the 0.940-micron water-vapor band to retrieve total-water-vapor data that is independent of surface reflectance properties and other atmospheric constituents. A channel combination is proposed to provide more accurate results, the SE-590 spectrometer is used to verify the data, and the effects of atmospheric photon backscattering is examined. The spectrometer and radiosonde data confirm the accuracy of using a narrow and a wide channel centered on the same wavelength to determine water vapor amounts. The technique is suitable for cloudless conditions and can contribute to atmospheric corrections of land-surface parameters.

  3. Micro-beam X-ray fluorescence and absorption imaging techniques at the IAEA Laboratories

    International Nuclear Information System (INIS)

    Wegrzynek, Dariusz; Markowicz, A.; Bamford, S.; Chinea-Cano, E.; Bogovac, M.

    2005-01-01

    X-ray tube based, micro-beam X-ray fluorescence scanning spectrometer has been equipped with two energy dispersive X-ray detectors. The two-detector configuration allows for simultaneous collection of X-ray fluorescence (XRF) and transmitted X-ray beam signals with a spatial resolution in the range of 10-50 μm, depending on the X-ray focussing element in use. The XRF signal is collected with a standard, liquid nitrogen cooled Si(Li) detector. The X-ray beam transmitted through the sample is acquired with a thermoelectrically cooled, silicon drift (SD) detector. The data acquisition is carried out in a fully automatic way under control of the SPECTOR-LOCATOR software. The software controls the scanning procedure and X-ray spectra acquisition during the scan. The energy dispersive X-ray spectra collected at every 'pixel' are stored for off-line processing. For selected regions of interest (ROI's), the element maps are constructed and displayed on-line. The spectrometer has been used for mapping elemental distributions and for performing 2D- and 3D-tomograpic imaging of minute objects in X-ray absorption and in X-ray fluorescence mode. A unique feature of the described system is simultaneous utilization of the two detectors, Si(Li) and SD, which adds new options for quantitative analysis and data interpretation. Examples of elemental mapping and 3D tomographic imaging as well as the advanced features of the SPECTOR-LOCATOR measurement control and data acquisition software are presented in this work

  4. A technique for lyopreservation of Clostridium ljungdahlii in a biocomposite matrix for CO absorption.

    Directory of Open Access Journals (Sweden)

    Mark J Schulte

    Full Text Available A system capable of biocatalytic conversion of distributed sources of single carbon gases such as carbon monoxide into hydrocarbons can be highly beneficial for developing commercially viable biotechnology applications in alternative energy. Several anaerobic bacterial strains can be used for such conversion. The anaerobic carbon monoxide-fixing bacteria Clostridium ljungdahlii OTA1 is a model CO assimilating microorganism that currently requires cryogenic temperature for storage of the viable strains. If these organisms can be stabilized and concentrated in thin films in advanced porous materials, it will enable development of high gas fraction, biocomposite absorbers with elevated carbon monoxide (CO mass transfer rate, that require minimal power input and liquid, and demonstrate elevated substrate consumption rate compared to conventional suspended cell bioreactors. We report development of a technique for dry-stabilization of C. ljungdahlii OTA1 on a paper biocomposite. Bacterial samples coated onto paper were desiccated in the presence of trehalose using convective drying and stored at 4°C. Optimal dryness was ~1g H2O per gram of dry weight (gDW. CO uptake directly following biocomposite rehydration steadily increases over time indicating immediate cellular metabolic recovery. A high-resolution Raman microspectroscopic hyperspectral imaging technique was employed to spatially quantify the residual moisture content. We have demonstrated for the first time that convectively dried and stored C. ljungdahlii strains were stabilized in a desiccated state for over 38 days without a loss in CO absorbing reactivity. The Raman hyperspectral imaging technique described here is a non-invasive characterization tool to support development of dry-stabilization techniques for microorganisms on inexpensive porous support materials. The present study successfully extends and implements the principles of dry-stabilization for preservation of strictly

  5. How Can Synchrotron Radiation Techniques Be Applied for Detecting Microstructures in Amorphous Alloys?

    Directory of Open Access Journals (Sweden)

    Gu-Qing Guo

    2015-11-01

    Full Text Available In this work, how synchrotron radiation techniques can be applied for detecting the microstructure in metallic glass (MG is studied. The unit cells are the basic structural units in crystals, though it has been suggested that the co-existence of various clusters may be the universal structural feature in MG. Therefore, it is a challenge to detect microstructures of MG even at the short-range scale by directly using synchrotron radiation techniques, such as X-ray diffraction and X-ray absorption methods. Here, a feasible scheme is developed where some state-of-the-art synchrotron radiation-based experiments can be combined with simulations to investigate the microstructure in MG. By studying a typical MG composition (Zr70Pd30, it is found that various clusters do co-exist in its microstructure, and icosahedral-like clusters are the popular structural units. This is the structural origin where there is precipitation of an icosahedral quasicrystalline phase prior to phase transformation from glass to crystal when heating Zr70Pd30 MG.

  6. Techniques of biomolecular quantification through AMS detection of radiocarbon

    International Nuclear Information System (INIS)

    Vogel, S.J.; Turteltaub, K.W.; Frantz, C.; Felton, J.S.; Gledhill, B.L.

    1992-01-01

    Accelerator mass spectrometry offers a large gain over scintillation counting in sensitivity for detecting radiocarbon in biomolecular tracing. Application of this sensitivity requires new considerations of procedures to extract or isolate the carbon fraction to be quantified, to inventory all carbon in the sample, to prepare graphite from the sample for use in the spectrometer, and to derive a meaningful quantification from the measured isotope ratio. These procedures need to be accomplished without contaminating the sample with radiocarbon, which may be ubiquitous in laboratories and on equipment previously used for higher dose, scintillation experiments. Disposable equipment, materials and surfaces are used to control these contaminations. Quantification of attomole amounts of labeled substances are possible through these techniques

  7. Preliminary detection of explosive standard components with Laser Raman Technique

    International Nuclear Information System (INIS)

    Botti, S.; Ciardi, R.

    2008-01-01

    Presently, our section is leader of the ISOTREX project (Integrated System for On-line TRace EXplosives detection in solid, liquid and vapour state), funded in the frame of the PASR 2006 action (Preparatory Action on the enhancement of the European industrial potential in the field of Security Research Preparatory Action) of the 6. EC framework. ISOTREX project will exploit the capabilities of different laser techniques as LIBS (Laser Induced Breakdown Spectroscopy), LPA (Laser Photo Acustic) and CRDS (Cavity Ring Down Spectroscopy) to monitor explosive traces. In this frame, we extended our investigation also to the laser induced Raman effect spectroscopy, in order to investigate its capabilities and possible future integration. We analysed explosive samples in bulk solid phase, diluted liquid phase and as evaporated films over suitable substrate. In the following, we present the main results obtained, outlining preliminary conclusions [it

  8. NO{sub 2} detection by DFWM and LITGS techniques

    Energy Technology Data Exchange (ETDEWEB)

    Fantoni, Roberta; Giorgi, Mariano [ENEA, Centro Ricerche Frascati, Rome (Italy). Dipt. Innovazione; De Dominicis, Luigi

    1997-03-01

    Laser-induced grating techniques indicated as D.F.W.M. (Degenerate Four Wave Mixing) and L.I.T.G.S. (Laser Induced Thermal Grating Spectroscopy) have been developed in different geometries in order to detect small concentration of nitric oxide in a broad pressure and temperature range. NO{sub 2} spectra in the Douglas-Huber band originating from the {sup 2} B{sub 1} (k` = 0) - {sup 2} A{sub 1} (k` = 1) transition have been measured at low and high resolution. The role played by population and thermal gratings has been investigated in various experimental conditions upon addition of buffer gases in calibration cells at room temperature and on heated samples.

  9. Detection of metal stress in boreal forest species using the 0.67-micron chlorophyll absorption band

    Science.gov (United States)

    Singhroy, Vernon H.; Kruse, Fred A.

    1991-01-01

    Several recent studies have shown that a shift of the red-edge inflection near 0.70 micron in vegetation reflectance spectra is an indicator of metal stress, partially attributable to changes in chlorophyll concentration. This 'red-edge shift', however, is difficult to detect and has been reported both toward longer (red) and shorter (blue) wavelengths. Our work demonstrates that direct measurement of the depth and width of the chlorophyll absorption band at 0.67 micron using digital feature extraction and absorption band characterization procedures developed for the analysis of mineral spectra is a more consistent indicator of metal stress. Additionally, the magnitude of these parameters is generally greater than that of the red edge shift and thus should be more amenable to detection and mapping using field and aircraft spectrometers.

  10. Detection of Anomalies in Hydrometric Data Using Artificial Intelligence Techniques

    Science.gov (United States)

    Lauzon, N.; Lence, B. J.

    2002-12-01

    This work focuses on the detection of anomalies in hydrometric data sequences, such as 1) outliers, which are individual data having statistical properties that differ from those of the overall population; 2) shifts, which are sudden changes over time in the statistical properties of the historical records of data; and 3) trends, which are systematic changes over time in the statistical properties. For the purpose of the design and management of water resources systems, it is important to be aware of these anomalies in hydrometric data, for they can induce a bias in the estimation of water quantity and quality parameters. These anomalies may be viewed as specific patterns affecting the data, and therefore pattern recognition techniques can be used for identifying them. However, the number of possible patterns is very large for each type of anomaly and consequently large computing capacities are required to account for all possibilities using the standard statistical techniques, such as cluster analysis. Artificial intelligence techniques, such as the Kohonen neural network and fuzzy c-means, are clustering techniques commonly used for pattern recognition in several areas of engineering and have recently begun to be used for the analysis of natural systems. They require much less computing capacity than the standard statistical techniques, and therefore are well suited for the identification of outliers, shifts and trends in hydrometric data. This work constitutes a preliminary study, using synthetic data representing hydrometric data that can be found in Canada. The analysis of the results obtained shows that the Kohonen neural network and fuzzy c-means are reasonably successful in identifying anomalies. This work also addresses the problem of uncertainties inherent to the calibration procedures that fit the clusters to the possible patterns for both the Kohonen neural network and fuzzy c-means. Indeed, for the same database, different sets of clusters can be

  11. Digital Image Processing Technique for Breast Cancer Detection

    Science.gov (United States)

    Guzmán-Cabrera, R.; Guzmán-Sepúlveda, J. R.; Torres-Cisneros, M.; May-Arrioja, D. A.; Ruiz-Pinales, J.; Ibarra-Manzano, O. G.; Aviña-Cervantes, G.; Parada, A. González

    2013-09-01

    Breast cancer is the most common cause of death in women and the second leading cause of cancer deaths worldwide. Primary prevention in the early stages of the disease becomes complex as the causes remain almost unknown. However, some typical signatures of this disease, such as masses and microcalcifications appearing on mammograms, can be used to improve early diagnostic techniques, which is critical for women’s quality of life. X-ray mammography is the main test used for screening and early diagnosis, and its analysis and processing are the keys to improving breast cancer prognosis. As masses and benign glandular tissue typically appear with low contrast and often very blurred, several computer-aided diagnosis schemes have been developed to support radiologists and internists in their diagnosis. In this article, an approach is proposed to effectively analyze digital mammograms based on texture segmentation for the detection of early stage tumors. The proposed algorithm was tested over several images taken from the digital database for screening mammography for cancer research and diagnosis, and it was found to be absolutely suitable to distinguish masses and microcalcifications from the background tissue using morphological operators and then extract them through machine learning techniques and a clustering algorithm for intensity-based segmentation.

  12. Mobile Techniques for Rapid Detection of Concealed Nuclear Material

    International Nuclear Information System (INIS)

    Rosenstock, W.; Koeble, T.; Risse, M.; Berky, W.

    2015-01-01

    To prevent the diversion of nuclear material as well as illicit production, transport and use of nuclear material we investigated in mobile techniques to detect and identify such material in the field as early as possible. For that purpose we use a highly sensitive gamma measurement system installed in a car. It consists of two large volume plastic scintillators, one on each side of the car, each scintillator with 12 l active volume, and two extreme sensitive high purity Germanium detectors with 57 cm 2 crystal diameter, cooled electrically. The measured data are processed immediately with integrated, appropriate analysis software for direct assessment including material identification and classification within seconds. The software for the plastic scintillators can differentiate between natural and artificial radioactivity, thus giving a clear hint for the existence of unexpected material. In addition, the system is equipped with highly sensitive neutron detectors. We have performed numerous measurements by passing different radioactive and nuclear sources in relatively large distances with this measurement car. Even shielded as well as masked material was detected and identified in most of the cases. We will report on the measurements performed in the field (on an exercise area) and in the lab and discuss the capabilities of the system, especially with respect to timeliness and identification. This system will improve the nuclear verification capabilities also. (author)

  13. In Situ Techniques for Life Detection on Mars

    Science.gov (United States)

    Becker, L.; Brinckerhoff, W.; Cotter, R.

    2006-12-01

    The search for organic matter on Mars is rapidly emerging as a result of technological advancements and the study of early "life" on our own planet. As we learned from the Viking missions and the examination of martian meteorites, the criteria for establishing life require the appropriate strategy. One such approach would require careful mapping of the surface from orbit for the selection of the appropriate landing sites, robotic space missions equipped with several life detection in situ techniques for selection of samples, and sample return missions for additional verification of in situ results and laboratory measurements. It may, however, be possible to obtain critical information about the organic matter and associated mineral assemblages present on Mars, in situ, in a single measurement that is both capable of flight and is nondestructive to the sample. We discuss a new multi-source mass spectrometer, `MOMA' (Mars Organic Molecule Analyzer) that incorporates multiple methods of volatilizing and ionizing chemical compounds from intact samples without further processing or manipulation. Moreover, MOMA is capable of detecting a broad range of organics enabling the evaluation of the origin of the organics and the presence of terrestrial contaminants.

  14. Instrumentation and signal processing for the detection of heavy water using off axis-integrated cavity output spectroscopy technique

    Science.gov (United States)

    Gupta, A.; Singh, P. J.; Gaikwad, D. Y.; Udupa, D. V.; Topkar, A.; Sahoo, N. K.

    2018-02-01

    An experimental setup is developed for the trace level detection of heavy water (HDO) using the off axis-integrated cavity output spectroscopy technique. The absorption spectrum of water samples is recorded in the spectral range of 7190.7 cm-1-7191.5 cm-1 with the diode laser as the light source. From the recorded water vapor absorption spectrum, the heavy water concentration is determined from the HDO and water line. The effect of cavity gain nonlinearity with per pass absorption is studied. The signal processing and data fitting procedure is devised to obtain linear calibration curves by including nonlinear cavity gain effects into the calculation. Initial calibration of mirror reflectivity is performed by measurements on the natural water sample. The signal processing and data fitting method has been validated by the measurement of the HDO concentration in water samples over a wide range from 20 ppm to 2280 ppm showing a linear calibration curve. The average measurement time is about 30 s. The experimental technique presented in this paper could be applied for the development of a portable instrument for the fast measurement of water isotopic composition in heavy water plants and for the detection of heavy water leak in pressurized heavy water reactors.

  15. Measurement of L3 subshell absorption jump ratios and jump factors for high Z elements using EDXRF technique

    International Nuclear Information System (INIS)

    Kaçal, M.R.

    2014-01-01

    Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring L 3 -subshell absorption jump ratios, r L 3 and jump factors, J L 3 for high Z elements. Jump factors and jump ratios for these elements have been determined by measuring L 3 subshell fluorescence parameters such as L 3 subshell X-ray production cross section σ L 3 , L 3 subshell fluorescence yield, ω L 3 , total L 3 subshell and higher subshells photoionization cross section σ L T . Measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation experimental geometry. Measured values for jump factors and jump ratios have been compared with theoretically calculated and other experimental values. - Highlights: • This paper regards L 3 subshell absorption jump ratios and jump factors using the EDXRF method. • These parameters were measured using a new method. • This method is more useful than other methods which require much effort. • Results are in good agreement with theoretical and experimental values

  16. Development of a methodology for low-energy X-ray absorption correction in biological samples using radiation scattering techniques

    International Nuclear Information System (INIS)

    Pereira, Marcelo O.; Anjos, Marcelino J.; Lopes, Ricardo T.

    2009-01-01

    Non-destructive techniques with X-ray, such as tomography, radiography and X-ray fluorescence are sensitive to the attenuation coefficient and have a large field of applications in medical as well as industrial area. In the case of X-ray fluorescence analysis the knowledge of photon X-ray attenuation coefficients provides important information to obtain the elemental concentration. On the other hand, the mass attenuation coefficient values are determined by transmission methods. So, the use of X-ray scattering can be considered as an alternative to transmission methods. This work proposes a new method for obtain the X-ray absorption curve through superposition peak Rayleigh and Compton scattering of the lines L a e L β of Tungsten (Tungsten L lines of an X-ray tube with W anode). The absorption curve was obtained using standard samples with effective atomic number in the range from 6 to 16. The method were applied in certified samples of bovine liver (NIST 1577B) , milk powder and V-10. The experimental measurements were obtained using the portable system EDXRF of the Nuclear Instrumentation Laboratory (LIN-COPPE/UFRJ) with Tungsten (W) anode. (author)

  17. Probing absorption of deuterium into palladium cathodes during D2O electrolysis with an in situ electrochemical microbalance technique

    International Nuclear Information System (INIS)

    Oyama, Noboru; Yamamoto, Nobushige; Hatozaki, Osamu; Ohsaka, Takeo

    1990-01-01

    The in situ observation of the absorption of deuterium (or hydrogen) into the Pd cathode during D 2 O (or H 2 O) electrolysis was made by an electrochemical microbalance technique which is based on the quartz-crystal electrode. The resonant frequency of the Pd-coated quartz-crystal electrode decreased with increasing amount of charge passed during electrolysis, and the frequency change for the D 2 O electrolysis was about twice that for the H 2 O electrolysis. The atom ratios of H/Pd and D/Pd of the H-Pd and D-Pd compounds resulting from the electrolysis were estimated to be 0.59 and 0.57, respectively. (author)

  18. Employing X-ray absorption technique for better detector resolution and measurement of low cross-section events

    Science.gov (United States)

    Sharma, Gaurav; Puri, Nitin K.; Kumar, Pravin; Nandi, T.

    2018-03-01

    The versatility of X-ray absorption technique is experimentally employed for enhancing the detector resolution and to rejuvenate the low probable transitions obscured in the pile-up region, during a beam-foil spectroscopy experiment. The multiple aluminum absorber layers (10 μm each) are used to suppress the pile-up contribution drastically and to restore a weak transition which is about 1.38 × 104 times weaker than a one-electron-one-photon transitions viz. Kα and Khα. The weak line is possibly originating from a two-electron-one-photon transition in He-like Ti. Further, the transitions, which were obscured in the spectra due to high intensity ratio, are revived by dissimilar line intensity attenuation using this technique. The measured lifetimes of Kα line with and without intensity attenuation match well within error bar. The present technique finds potential implications in understanding the structure of multiple-core-vacant ions and other low cross section processes in ion-solid collisions.

  19. Modified Single Photo-diode (MSPD) Detection Technique for SAC-OCDMA System

    Science.gov (United States)

    Abdulqader, Sarah G.; Fadhil, Hilal A.; Aljunid, S. A.

    2015-03-01

    In this paper, a new detection technique called modified single photo-diode (MSPD) detection for SAC-OCDMA system is proposed. The proposed system based on the single photo-diode (SPD) detection technique. The new detection technique is proposed to overcome the limitation of phase-induced intensity noise (PIIN) in SPD detection technique. However, the proposed detection is based on an optical hard limiter (OHL) followed by a SPD and a low-pass filter (LPF) in order to suppress the phase intensity noise (PIIN) at the receiver side. The results show that the MSPD detection based on OHL has a good performance even when the transmission distance is long, which is different from the case of SPD detection technique. Therefore, the MSPD detection technique is shown to be effective to improve the bit error rate (BER<10-9) and to suppress the noise in the practical optical fiber network.

  20. Absorption studies

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    Absorption studies were once quite popular but hardly anyone does them these days. It is easier to estimate the blood level of the nutrient directly by radioimmunoassay (RIA). However, the information obtained by estimating the blood levels of the nutrients is not the same that can be obtained from the absorption studies. Absorption studies are primarily done to find out whether some of the essential nutrients are absorbed from the gut or not and if they are absorbed, to determine how much is being absorbed. In the advanced countries, these tests were mostly done to detect pernicious anaemia where vitamin B 12 is not absorbed because of the lack of the intrinsic factor in the stomach. In the tropical countries, ''malabsorption syndrome'' is quire common. In this condition, several nutrients like fat, folic acid and vitamin B 12 are not absorbed. It is possible to study absorption of these nutrients by radioisotopic absorption studies

  1. Online technique for detecting state of onboard fiber optic gyroscope

    International Nuclear Information System (INIS)

    Miao, Zhiyong; He, Kunpeng; Pang, Shuwan; Xu, Dingjie; Tian, Chunmiao

    2015-01-01

    Although angle random walk (ARW) of fiber optic gyroscope (FOG) has been well modeled and identified before being integrated into the high-accuracy attitude control system of satellite, aging and unexpected failures can affect the performance of FOG after launch, resulting in the variation of ARW coefficient. Therefore, the ARW coefficient can be regarded as an indicator of “state of health” for FOG diagnosis in some sense. The Allan variance method can be used to estimate ARW coefficient of FOG, however, it requires a large amount of data to be stored. Moreover, the procedure of drawing slope lines for estimation is painful. To overcome the barriers, a weighted state-space model that directly models the ARW to obtain a nonlinear state-space model was established for FOG. Then, a neural extended-Kalman filter algorithm was implemented to estimate and track the variation of ARW in real time. The results of experiment show that the proposed approach is valid to detect the state of FOG. Moreover, the proposed technique effectively avoids the storage of data

  2. Online technique for detecting state of onboard fiber optic gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Zhiyong; He, Kunpeng, E-mail: pengkhe@126.com; Pang, Shuwan [Department of Automation, Harbin Engineering University, Harbin, Heilongjiang 150000 (China); Xu, Dingjie [School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin, Heilongjiang 150000 (China); Tian, Chunmiao [Department of Information and Communication Engineering, Harbin Engineering University, Harbin, Heilongjiang 150000 (China)

    2015-02-15

    Although angle random walk (ARW) of fiber optic gyroscope (FOG) has been well modeled and identified before being integrated into the high-accuracy attitude control system of satellite, aging and unexpected failures can affect the performance of FOG after launch, resulting in the variation of ARW coefficient. Therefore, the ARW coefficient can be regarded as an indicator of “state of health” for FOG diagnosis in some sense. The Allan variance method can be used to estimate ARW coefficient of FOG, however, it requires a large amount of data to be stored. Moreover, the procedure of drawing slope lines for estimation is painful. To overcome the barriers, a weighted state-space model that directly models the ARW to obtain a nonlinear state-space model was established for FOG. Then, a neural extended-Kalman filter algorithm was implemented to estimate and track the variation of ARW in real time. The results of experiment show that the proposed approach is valid to detect the state of FOG. Moreover, the proposed technique effectively avoids the storage of data.

  3. Folate absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Folate is the generic term given to numerous compounds of pteroic acid with glutamic acid. Knowledge of absorption is limited because of the complexities introduced by the variety of compounds and because of the inadequacy of investigational methods. Two assay methods are in use, namely microbiological and radioactive. Techniques used to study absorption include measurement of urinary excretion, serum concentration, faecal excretion, intestinal perfusion, and haematological response. It is probably necessary to test absorption of both pteroylmonoglutamic acid and one or more polyglutamates, and such tests would be facilitated by availability of synthesized compounds labelled with radioactive tracers at specifically selected sites. (author)

  4. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    KAUST Repository

    Alquaity, Awad

    2017-11-11

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm−1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10−5 cm−1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  5. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    KAUST Repository

    Alquaity, Awad; KC, Utsav; Popov, Alber; Farooq, Aamir

    2017-01-01

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm−1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10−5 cm−1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  6. Extraction and preconcentration of trace levels of cobalt using functionalized magnetic nanoparticles in a sequential injection lab-on-valve system with detection by electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Wang Yang; Luo Xiaoyu; Tang Jie; Hu Xiaoya; Xu Qin; Yang Chun

    2012-01-01

    Graphical abstract: An approach to performing extraction and preconcentration employing functionalized magnetic particles for the determination of cobalt in the sequential injection lab-on-valve system using detection by electrothermal atomic absorption spectrometry. Highlights: ► New SPE method for cobalt separation/preconcentration was reported. ► Functionalized magnetic nanoparticles were used as adsorbent. ► Extraction, elution, and detection procedures were performed in the LOV system. ► This automatic extraction technique provided a good platform for metal analysis. - Abstract: A new approach to performing extraction and preconcentration employing functionalized magnetic nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solid phase extraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal atomic absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized magnetic adsorbents. The potential use of the established scheme was demonstrated by taking cobalt as a model analyte. Under the optimal conditions, the calibration curve showed an excellent linearity in the concentration range of 0.01–5 μg L −1 , and the relative standard deviation was 2.8% at the 0.5 μg L −1 level (n = 11). The limit of detection was 6 ng L −1 with a sampling frequency of 18 h −1 . The present method has been successfully applied to cobalt determination in water samples and two certified reference materials.

  7. A technique for simultaneous detection of individual vortex states of Laguerre-Gaussian beams transmitted through an aqueous suspension of microparticles

    Science.gov (United States)

    Khonina, S. N.; Karpeev, S. V.; Paranin, V. D.

    2018-06-01

    A technique for simultaneous detection of individual vortex states of the beams propagating in a randomly inhomogeneous medium is proposed. The developed optical system relies on the correlation method that is invariant to the beam wandering. The intensity distribution formed at the optical system output does not require digital processing. The proposed technique based on a multi-order phase diffractive optical element (DOE) is studied numerically and experimentally. The developed detection technique is used for the analysis of Laguerre-Gaussian vortex beams propagating under conditions of intense absorption, reflection, and scattering in transparent and opaque microparticles in aqueous suspensions. The performed experimental studies confirm the relevance of the vortex phase dependence of a laser beam under conditions of significant absorption, reflection, and scattering of the light.

  8. Robust techniques for polarization and detection of nuclear spin ensembles

    Science.gov (United States)

    Scheuer, Jochen; Schwartz, Ilai; Müller, Samuel; Chen, Qiong; Dhand, Ish; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

    2017-11-01

    Highly sensitive nuclear spin detection is crucial in many scientific areas including nuclear magnetic resonance spectroscopy, magnetic resonance imaging (MRI), and quantum computing. The tiny thermal nuclear spin polarization represents a major obstacle towards this goal which may be overcome by dynamic nuclear spin polarization (DNP) methods. The latter often rely on the transfer of the thermally polarized electron spins to nearby nuclear spins, which is limited by the Boltzmann distribution of the former. Here we utilize microwave dressed states to transfer the high (>92 % ) nonequilibrium electron spin polarization of a single nitrogen-vacancy center (NV) induced by short laser pulses to the surrounding 13C carbon nuclear spins. The NV is repeatedly repolarized optically, thus providing an effectively infinite polarization reservoir. A saturation of the polarization of the nearby nuclear spins is achieved, which is confirmed by the decay of the polarization transfer signal and shows an excellent agreement with theoretical simulations. Hereby we introduce the polarization readout by polarization inversion method as a quantitative magnetization measure of the nuclear spin bath, which allows us to observe by ensemble averaging macroscopically hidden polarization dynamics like Landau-Zener-Stückelberg oscillations. Moreover, we show that using the integrated solid effect both for single- and double-quantum transitions nuclear spin polarization can be achieved even when the static magnetic field is not aligned along the NV's crystal axis. This opens a path for the application of our DNP technique to spins in and outside of nanodiamonds, enabling their application as MRI tracers. Furthermore, the methods reported here can be applied to other solid state systems where a central electron spin is coupled to a nuclear spin bath, e.g., phosphor donors in silicon and color centers in silicon carbide.

  9. Laboratory insights into the detection of surface biosignatures by remote-sensing techniques

    Science.gov (United States)

    Poch, O.; Pommerol, A.; Jost, B.; Roditi, I.; Frey, J.; Thomas, N.

    2014-03-01

    With the progress of direct imaging techniques, it will be possible in the short or long-term future to retrieve more efficiently the information on the physical properties of the light reflected by rocky exoplanets (Traub et al., 2010). The search for visible-infrared absorption bands of peculiar gases (O2, CH4 etc.) in this light could give clues for the presence of life (Kaltenegger and Selsis, 2007). Even more uplifting would be the direct detection of life itself, on the surface of an exoplanet. Considering this latter possibility, what is the potential of optical remote-sensing methods to detect surface biosignatures? Reflected light from the surface of the Earth exhibits a strong surface biosignature in the form of an abrupt change of reflectance between the visible and infrared range of the spectrum (Seager et al., 2005). This spectral feature called "vegetation red-edge" is possibly the consequence of biological evolution selecting the right chemical structures enabling the plants to absorb the visible energy, while preventing them from overheating by reflecting more efficiently the infrared. Such red-edge is also found in primitive photosynthetic bacteria, cyanobacteria, that colonized the surface of the Earth ocean and continents billions of years before multicellular plants (Knacke, 2003). If life ever arose on an Earth-like exoplanet, one could hypothesize that some form of its surface-life evolves into similar photo-active organisms, also exhibiting a red-edge. In this paper, we will present our plan and preliminary results of a laboratory study aiming at precising the potentiality of remote sensing techniques in detecting such surface biosignatures. Using equipment that has been developed in our team for surface photometry studies (Pommerol 2011, Jost 2013, Pommerol 2013), we will investigate the reflectance spectra and bidirectional reflectance function of soils containing bacteria such as cyanobacteria, in various environmental conditions. We will

  10. First Time Rapid and Accurate Detection of Massive Number of Metal Absorption Lines in the Early Universe Using Deep Neural Network

    Science.gov (United States)

    Zhao, Yinan; Ge, Jian; Yuan, Xiaoyong; Li, Xiaolin; Zhao, Tiffany; Wang, Cindy

    2018-01-01

    Metal absorption line systems in the distant quasar spectra have been used as one of the most powerful tools to probe gas content in the early Universe. The MgII λλ 2796, 2803 doublet is one of the most popular metal absorption lines and has been used to trace gas and global star formation at redshifts between ~0.5 to 2.5. In the past, machine learning algorithms have been used to detect absorption lines systems in the large sky survey, such as Principle Component Analysis, Gaussian Process and decision tree, but the overall detection process is not only complicated, but also time consuming. It usually takes a few months to go through the entire quasar spectral dataset from each of the Sloan Digital Sky Survey (SDSS) data release. In this work, we applied the deep neural network, or “ deep learning” algorithms, in the most recently SDSS DR14 quasar spectra and were able to randomly search 20000 quasar spectra and detect 2887 strong Mg II absorption features in just 9 seconds. Our detection algorithms were verified with previously released DR12 and DR7 data and published Mg II catalog and the detection accuracy is 90%. This is the first time that deep neural network has demonstrated its promising power in both speed and accuracy in replacing tedious, repetitive human work in searching for narrow absorption patterns in a big dataset. We will present our detection algorithms and also statistical results of the newly detected Mg II absorption lines.

  11. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    International Nuclear Information System (INIS)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    A method for a direct measurement of X-ray projections of the atomic structure is described. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy pattern detected using Nb K fluorescence. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples

  12. Detection of cancerous biological tissue areas by means of infrared absorption and SERS spectroscopy of intercellular fluid

    Science.gov (United States)

    Velicka, M.; Urboniene, V.; Ceponkus, J.; Pucetaite, M.; Jankevicius, F.; Sablinskas, V.

    2015-08-01

    We present a novel approach to the detection of cancerous kidney tissue areas by measuring vibrational spectra (IR absorption or SERS) of intercellular fluid taken from the tissue. The method is based on spectral analysis of cancerous and normal tissue areas in order to find specific spectral markers. The samples were prepared by sliding the kidney tissue over a substrate - surface of diamond ATR crystal in case of IR absorption or calcium fluoride optical window in case of SERS. For producing the SERS signal the dried fluid film was covered by silver nanoparticle colloidal solution. In order to suppress fluorescence background the measurements were performed in the NIR spectral region with the excitation wavelength of 1064 nm. The most significant spectral differences - spectral markers - were found in the region between 400 and 1800 cm-1, where spectral bands related to various vibrations of fatty acids, glycolipids and carbohydrates are located. Spectral markers in the IR and SERS spectra are different and the methods can complement each other. Both of them have potential to be used directly during surgery. Additionally, IR absorption spectroscopy in ATR mode can be combined with waveguide probe what makes this method usable in vivo.

  13. [Gastric cancer detection using kubelka-Munk spectral function of DNA and protein absorption bands].

    Science.gov (United States)

    Li, Lan-quan; Wei, Hua-jiang; Guo, Zhou-yi; Yang, Hong-qin; Xie, Shu-sen; Chen, Xue-mei; Li, Li-bo; He, Bol-hua; Wu, Guo-yong; Lu, Jian-jun

    2009-09-01

    Differential diagnosis for epithelial tissues of normal human gastric, undifferentiation gastric adenocarcinoma, gastric squamous cell carcinomas, and poorly differentiated gastric adenocarcinoma were studied using the Kubelka-Munk spectral function of the DNA and protein absorption bands at 260 and 280 nm in vitro. Diffuse reflectance spectra of tissue were measured using a spectrophotometer with an integrating sphere attachment. The results of measurement showed that for the spectral range from 250 to 650 nm, pathological changes of gastric epithelial tissues induced that there were significant differences in the averaged value of the Kubelka-Munk function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the DNA absorption bands at 260 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 68.5% (p function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the protein absorption bands at 280 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 86.8% (p function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the carotene absorption bands at 480 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 59.5% (p < 0.05), 73% (p < 0

  14. Driver drowsiness detection using behavioral measures and machine learning techniques: A review of state-of-art techniques

    CSIR Research Space (South Africa)

    Ngxande, Mkhuseli

    2017-11-01

    Full Text Available This paper presents a literature review of driver drowsiness detection based on behavioral measures using machine learning techniques. Faces contain information that can be used to interpret levels of drowsiness. There are many facial features...

  15. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    OpenAIRE

    Dong, Ming; Zhang, Chongxing; Ren, Ming; Albarracín, Ricardo; Ye, Rixin

    2017-01-01

    Sulfur hexafluoride (SF6) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes ...

  16. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Directory of Open Access Journals (Sweden)

    Ming Dong

    2017-11-01

    Full Text Available Sulfur hexafluoride (SF6 gas-insulated electrical equipment is widely used in high-voltage (HV and extra-high-voltage (EHV power systems. Partial discharge (PD and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES and infrared (IR spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations.

  17. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Science.gov (United States)

    Dong, Ming; Ren, Ming; Ye, Rixin

    2017-01-01

    Sulfur hexafluoride (SF6) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations. PMID:29140268

  18. GREEN BANK TELESCOPE DETECTION OF POLARIZATION-DEPENDENT H I ABSORPTION AND H I OUTFLOWS IN LOCAL ULIRGs AND QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Stacy H. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Veilleux, Sylvain [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Baker, Andrew J., E-mail: stacy.h.teng@nasa.gov [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States)

    2013-03-10

    We present the results of a 21 cm H I survey of 27 local massive gas-rich late-stage mergers and merger remnants with the Robert C. Byrd Green Bank Telescope. These remnants were selected from the Quasar/ULIRG Evolution Study sample of ultraluminous infrared galaxies (ULIRGs; L{sub 8{sub -{sub 1000{sub {mu}m}}}} > 10{sup 12} L{sub Sun }) and quasars; our targets are all bolometrically dominated by active galactic nuclei (AGNs) and sample the later phases of the proposed ULIRG-to-quasar evolutionary sequence. We find the prevalence of H I absorption (emission) to be 100% (29%) in ULIRGs with H I detections, 100% (88%) in FIR-strong quasars, and 63% (100%) in FIR-weak quasars. The absorption features are associated with powerful neutral outflows that change from being mainly driven by star formation in ULIRGs to being driven by the AGN in the quasars. These outflows have velocities that exceed 1500 km s{sup -1} in some cases. Unexpectedly, we find polarization-dependent H I absorption in 57% of our spectra (88% and 63% of the FIR-strong and FIR-weak quasars, respectively). We attribute this result to absorption of polarized continuum emission from these sources by foreground H I clouds. About 60% of the quasars displaying polarized spectra are radio-loud, far higher than the {approx}10% observed in the general AGN population. This discrepancy suggests that radio jets play an important role in shaping the environments in these galaxies. These systems may represent a transition phase in the evolution of gas-rich mergers into ''mature'' radio galaxies.

  19. Development of detection techniques for the Swedish noble gas sampler

    International Nuclear Information System (INIS)

    Ringbom, A.

    1998-11-01

    A short review on the radioactive properties of noble gas isotopes relevant for monitoring of nuclear activities is given, together with a brief discussion of the existing systems for detection of radioactive noble gases. A 4π detection system to be used in the automatic version of the Swedish noble gas sampling device is described. Monte Carlo calculations of the total gamma and beta efficiency for different detector designs have been performed, together with estimates of the resulting minimum detectable concentration (MDC). The estimated MDC values for detection of the 133g Xe 81 keV and the 135g Xe 250 keV gamma lines are around 0.3 mBq/m 3 in both cases. This is a factor of three lower than the detection limit required for a sampling station in the Comprehensive Nuclear-Test-Ban Treaty monitoring network. The possibility to modify the system to detect 85 Kr is also discussed

  20. Detection and sizing of cracks using potential drop techniques based on electromagnetic induction

    International Nuclear Information System (INIS)

    Sato, Yasumoto; Kim, Hoon

    2011-01-01

    The potential drop techniques based on electromagnetic induction are classified into induced current focused potential drop (ICFPD) technique and remotely induced current potential drop (RICPD) technique. The possibility of numerical simulation of the techniques is investigated and the applicability of these techniques to the measurement of defects in conductive materials is presented. Finite element analysis (FEA) for the RICPD measurements on the plate specimen containing back wall slits is performed and calculated results by FEA show good agreement with experimental results. Detection limit of the RICPD technique in depth of back wall slits can also be estimated by FEA. Detection and sizing of artificial defects in parent and welded materials are successfully performed by the ICFPD technique. Applicability of these techniques to detection of cracks in field components is investigated, and most of the cracks in the components investigated are successfully detected by the ICFPD and RICPD techniques. (author)

  1. Metal and trace element assessment of estuary sediments from Santos, Brazil, by neutron activation and atomic absorption techniques

    International Nuclear Information System (INIS)

    Amorim, Eduardo P.; Favaro, Deborah I.T.; Berbel, Glaucia B.B.; Braga, Elisabete S.

    2007-01-01

    In order to better understanding geochemical and environmental processes and their possible changes due to anthropogenic activities trace metal analyses and their distribution in marine sediments are commonly undertaken. The present study reports result concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirteen bottom sediment samples (SV0501 to SV0513) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao, Vicente de Carvalho and Santos' Bay, in the summer of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). For total mercury determination cold vapor atomic absorption technique (CV AAS) was employed. In both cases methodology validation was performed by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared with NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values). In general, the samples located near the Cubatao region showed higher concentrations for all elements analyzed probably due to the high impact of industrial activities. (author)

  2. Metal and trace element assessment of estuary sediments from Santos, Brazil, by neutron activation and atomic absorption techniques

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Eduardo P.; Favaro, Deborah I.T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: ducamorim@yahoo.com.br; defavaro@ipen.br; Berbel, Glaucia B.B.; Braga, Elisabete S. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos - LABNUT]. E-mail: edsbraga@usp.br

    2007-07-01

    In order to better understanding geochemical and environmental processes and their possible changes due to anthropogenic activities trace metal analyses and their distribution in marine sediments are commonly undertaken. The present study reports result concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirteen bottom sediment samples (SV0501 to SV0513) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao, Vicente de Carvalho and Santos' Bay, in the summer of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). For total mercury determination cold vapor atomic absorption technique (CV AAS) was employed. In both cases methodology validation was performed by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared with NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values). In general, the samples located near the Cubatao region showed higher concentrations for all elements analyzed probably due to the high impact of industrial activities. (author)

  3. Applications of the direct photon absorption technique for measuring bone mineral content in vivo. Determination of body composition in vivo

    Science.gov (United States)

    Cameron, J. R.

    1972-01-01

    The bone mineral content, BMC, determined by monoenergetic photon absorption technique, of 29 different locations on the long bones and vertebral columns of 24 skeletons was measured. Compressive tests were made on bone from these locations in which the maximum load and maximum stress were measured. Also the ultimate strain, modulus of elasticity and energy absorbed to failure were determined for compact bone from the femoral diaphysis and cancellous bone from the eighth through eleventh thoracic vertebrae. Correlations and predictive relationships between these parameters were examined to investigate the applicability of using the BMC at sites normally measured in vivo, i.e. radius and ulna in estimating the BMC and/or strength of the spine or femoral neck. It was found that the BMC at sites on the same bone were highly correlated r = 0.95 or better; the BMC at sites on different bones were also highly interrelated, r = 0.85. The BMC at various sites on the long bones could be estimated to between 10 and 15 per cent from the BMC of sites on the radius or ulna.

  4. Evaluation of various techniques for the pretreatment of sewage sludges prior to trace metal analysis by atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Smith, R.

    1983-01-01

    Six techniques were evaluated for their suitability for the pretreatment of dried sewage sludge prior to trace metal analysis by atomic absorption spectrophotometry. The evaluation comprised analysis of two prepared samples of dried sludge for aluminium, cadmium, chromium, copper, iron, lead, manganese, nickel and zinc, after the following pretreatment: dry ashing at 500 degrees Celsius followed by extraction with dilute hydrochloric acid; dry ashing at 500 degrees Celsius followed by extraction with aqua regia; nitric acid digestion followed by extraction with hydrochloric acid; extraction with aqua regia; ashing with magnesium nitrate solution at 550 degrees Celsius followed by digestion with hydrochloric acid and extraction with nitric acid; extraction with nitric acid. Procedures involving the use of perchloric acid, hydrofluoric acid and hydrogen peroxide were not considered for reasons of safety. Except in the case of aluminium the direct mineral acid digestion and/or extraction methods generally gave higher recoveries than the procedures incorporating an ashing step. Direct extraction of the sample with aqua regia was recommended as a rapid and simple general method of sample pretreatment prior to analysis for all the metals investigated except aluminium. For this metal, more drastic sample pretreatment will be required, for example fusion or hydrofluoric acid digestion

  5. Hyperspectral remote sensing techniques for early detection of plant diseases

    Science.gov (United States)

    Krezhova, Dora; Maneva, Svetla; Zdravev, Tomas

    Hyperspectral remote sensing is an emerging, multidisciplinary field with diverse applications in Earth observation. Nowadays spectral remote sensing techniques allow presymptomatic monitoring of changes in the physiological state of plants with high spectral resolution. Hyperspectral leaf reflectance and chlorophyll fluorescence proved to be highly suitable for identification of growth anomalies of cultural plants that result from the environmental changes and different stress factors. Hyperspectral technologies can find place in many scientific areas, as well as for monitoring of plants status and functioning to help in making timely management decisions. This research aimed to detect a presence of viral infection in young pepper plants (Capsicum annuum L.) caused by Cucumber Mosaic Virus (CMV) by using hyperspectral reflectance and fluorescence data and to assess the effect of some growth regulators on the development of the disease. In Bulgaria CMV is one of the widest spread pathogens, causing the biggest economical losses in crop vegetable production. Leaf spectral reflectance and fluorescence data were collected by a portable fibre-optics spectrometer in the spectral ranges 450÷850 nm and 600-900 nm. Greenhouse experiment with pepper plants of two cultivars, Sivria (sensitive to CMV) and Ostrion (resistant to CMV) were used. The plants were divided into six groups. The first group consisted of healthy (control) plants. At growth stage 4-6 expanded leaf, the second group was inoculated with CMV. The other four groups were treated with growth regulators: Spermine, MEIA (beta-monomethyl ester of itaconic acid), BTH (benzo(1,2,3)thiadiazole-7-carbothioic acid-S-methyl ester) and Phytoxin. On the next day, the pepper plants of these four groups were inoculated with CMV. The viral concentrations in the plants were determined by the serological method DAS-ELISA. Statistical, first derivative and cluster analysis were applied and several vegetation indices were

  6. Molecular techniques: An overview of methods for the detection of ...

    African Journals Online (AJOL)

    Several DNA molecular markers are now available for use in surveillance and investigation of food-borne outbreaks that were previously difficult to detect. The results from several sources of literature indicate substantially different degrees of sensitivities between conventional detection methods and molecular-based ...

  7. Nuclear resonance absorption (NRA): method and application to detection of contraband in a baggage, cargo and vehicles

    International Nuclear Information System (INIS)

    Goldenberg, M.B.; Vartsky, D.; Engler, G.

    1996-01-01

    Nuclear Resonance Absorption (NRA) has played a prominent role in nuclear spectroscopy for almost 5 decades, but found only few and marginal applications outside the laboratory before 1985. In that year the situation changed markedly when scientists from this laboratory proposed to the Federal Aviation Administration (FAA) in the U.S. to study its suitability for detecting explosives in passenger baggage via nitrogen-specific radiographic imaging (explosives, as a category, have inordinately high nitrogen densities). Following a basic feasibility study and the first laboratory demonstration of explosives detection in 1989, this project has attained the stage of a pre-industrial prototype that exhibited excellent performance characteristics in a 1993 blind test conducted by the FAA. In terms of NRA operational system concept, data taking methodology, development of dedicated detectors and image analysis algorithms, the Soreq group has made a major, if not exclusive, contribution over the years. (authors)

  8. Use of the gamma-ray absorption technique as a quality control procedure in the manufacture of powder metal shaped charge liners

    CSIR Research Space (South Africa)

    Lawrie, JJ

    2010-09-01

    Full Text Available The use of the gamma-ray absorption technique as a tool in evaluating the quality of manufactured powder metal liners was investigated. With powder metal liners, it is not only of interest to know whether the liner conforms geometrically...

  9. Mercury in Environmental and Biological Samples Using Online Combustion with Sequential Atomic Absorption and Fluorescence Measurements: A Direct Comparison of Two Fundamental Techniques in Spectrometry

    Science.gov (United States)

    Cizdziel, James V.

    2011-01-01

    In this laboratory experiment, students quantitatively determine the concentration of an element (mercury) in an environmental or biological sample while comparing and contrasting the fundamental techniques of atomic absorption spectrometry (AAS) and atomic fluorescence spectrometry (AFS). A mercury analyzer based on sample combustion,…

  10. Ultrasound-assisted extraction technique for establishing selenium contents in breast cancer biopsies by Zeeman-electrothermal atomic absorption spectrometry using multi-injection

    International Nuclear Information System (INIS)

    Lavilla, I.; Mosquera, A.; Millos, J.; Cameselle, J.; Bendicho, C.

    2006-01-01

    A solid-liquid extraction method is developed to establish the contents of selenium in breast cancer biopsies. The method is based on the ultrasound-assisted extraction of selenium from pretreated biopsies prior to Se determination by atomic absorption spectrometry with longitudinal-Zeeman background correction. Fifty-one breast biopsies were collected from the Cies Hospital (Vigo, Spain), 32 of which correspond to tumor tissue and 19 to normal tissue (parenchyma). Difficulties arising from the samples analyzed, i.e. small samples mass (50-100 mg), extremely low Se contents and sample texture modification including tissue hardening due to formaldehyde preservation are addressed and overcome. High intensity sonication using a probe together with addition of hydrogen peroxide succeeded in completely extracting Se from biopsies. The multiple injection technique was useful to tackle the low Se contents present in some biopsies. The detection limit was 25 ng g -1 of Se and the precision, expressed as relative standard deviation, was less than 10%. Se contents ranged from 0.08 to 0.4 μg g -1 for parenchyma samples and from 0.09 to 0.8 μg g -1 for tumor samples. In general, Se levels in tumor biopsies were higher as compared with the adjacent normal tissue in 19 patients by a factor of up to 6. Analytical data confirmed Se accumulation in the breast tumors

  11. An automated flow injection system for metal determination by flame atomic absorption spectrometry involving on-line fabric disk sorptive extraction technique.

    Science.gov (United States)

    Anthemidis, A; Kazantzi, V; Samanidou, V; Kabir, A; Furton, K G

    2016-08-15

    A novel flow injection-fabric disk sorptive extraction (FI-FDSE) system was developed for automated determination of trace metals. The platform was based on a minicolumn packed with sol-gel coated fabric media in the form of disks, incorporated into an on-line solid-phase extraction system, coupled with flame atomic absorption spectrometry (FAAS). This configuration provides minor backpressure, resulting in high loading flow rates and shorter analytical cycles. The potentials of this technique were demonstrated for trace lead and cadmium determination in environmental water samples. The applicability of different sol-gel coated FPSE media was investigated. The on-line formed complex of metal with ammonium pyrrolidine dithiocarbamate (APDC) was retained onto the fabric surface and methyl isobutyl ketone (MIBK) was used to elute the analytes prior to atomization. For 90s preconcentration time, enrichment factors of 140 and 38 and detection limits (3σ) of 1.8 and 0.4μgL(-1) were achieved for lead and cadmium determination, respectively, with a sampling frequency of 30h(-1). The accuracy of the proposed method was estimated by analyzing standard reference materials and spiked water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Cell-Detection Technique for Automated Patch Clamping

    Science.gov (United States)

    McDowell, Mark; Gray, Elizabeth

    2008-01-01

    A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image

  13. Field experience with advanced inservice inspection NDE-techniques for detection and sizing

    International Nuclear Information System (INIS)

    Engl, G.; Kronig, M.

    1988-01-01

    This document deals with Non-Destructive Examination (NDE) techniques used for the detection and sizing of cracks. Several techniques, such as L-SAFT, ALOK and Phased Array with UT-Tomography are discussed and compared. (TEC)

  14. Field experience with advanced inservice inspection NDE-techniques for detection and sizing

    Energy Technology Data Exchange (ETDEWEB)

    Engl, G; Kronig, M

    1988-12-31

    This document deals with Non-Destructive Examination (NDE) techniques used for the detection and sizing of cracks. Several techniques, such as L-SAFT, ALOK and Phased Array with UT-Tomography are discussed and compared. (TEC).

  15. Novel Fiber Optic Sensor Probe with a Pair of Highly Reflected Connectors and a Vessel of Water Absorption Material for Water Leak Detection

    Directory of Open Access Journals (Sweden)

    Tae-Sik Cho

    2012-08-01

    Full Text Available The use of a fiber optic quasi-distributed sensing technique for detecting the location and severity of water leakage is suggested. A novel fiber optic sensor probe is devised with a vessel of water absorption material called as water combination soil (WCS located between two highly reflected connectors: one is a reference connector and the other is a sensing connector. In this study, the sensing output is calculated from the reflected light signals of the two connectors. The first reflected light signal is a reference and the second is a sensing signal which is attenuated by the optical fiber bending loss due to the WCS expansion absorbing water. Also, the bending loss of each sensor probe is determined by referring to the total number of sensor probes and the total power budget of an entire system. We have investigated several probe characteristics to show the design feasibility of the novel fiber sensor probe. The effects of vessel sizes of the probes on the water detection sensitivity are studied. The largest vessel probe provides the highest sensitivity of 0.267 dB/mL, while the smallest shows relatively low sensitivity of 0.067 dB/mL, and unstable response. The sensor probe with a high output value provides a high sensitivity with various detection levels while the number of total installable sensor probes decreases.

  16. Novel fiber optic sensor probe with a pair of highly reflected connectors and a vessel of water absorption material for water leak detection.

    Science.gov (United States)

    Cho, Tae-Sik; Choi, Ki-Sun; Seo, Dae-Cheol; Kwon, Il-Bum; Lee, Jung-Ryul

    2012-01-01

    The use of a fiber optic quasi-distributed sensing technique for detecting the location and severity of water leakage is suggested. A novel fiber optic sensor probe is devised with a vessel of water absorption material called as water combination soil (WCS) located between two highly reflected connectors: one is a reference connector and the other is a sensing connector. In this study, the sensing output is calculated from the reflected light signals of the two connectors. The first reflected light signal is a reference and the second is a sensing signal which is attenuated by the optical fiber bending loss due to the WCS expansion absorbing water. Also, the bending loss of each sensor probe is determined by referring to the total number of sensor probes and the total power budget of an entire system. We have investigated several probe characteristics to show the design feasibility of the novel fiber sensor probe. The effects of vessel sizes of the probes on the water detection sensitivity are studied. The largest vessel probe provides the highest sensitivity of 0.267 dB/mL, while the smallest shows relatively low sensitivity of 0.067 dB/mL, and unstable response. The sensor probe with a high output value provides a high sensitivity with various detection levels while the number of total installable sensor probes decreases.

  17. A correlation-based pulse detection technique for gamma-ray/neutron detectors

    International Nuclear Information System (INIS)

    Faisal, Muhammad; Schiffer, Randolph T.; Flaska, Marek; Pozzi, Sara A.; Wentzloff, David D.

    2011-01-01

    We present a correlation-based detection technique that significantly improves the probability of detection for low energy pulses. We propose performing a normalized cross-correlation of the incoming pulse data to a predefined pulse template, and using a threshold correlation value to trigger the detection of a pulse. This technique improves the detector sensitivity by amplifying the signal component of incoming pulse data and rejecting noise. Simulation results for various different templates are presented. Finally, the performance of the correlation-based detection technique is compared to the current state-of-the-art techniques.

  18. Quantitative Emboli Detection Using Nonlinear Ultrasound Technique, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a new and innovative method for the detection and classification of emboli flowing into the brain through Carotid arteries, specifically for...

  19. Crack Detection in Armor Plates Using Ultrasonic Techniques

    National Research Council Canada - National Science Library

    Meitzler, Thomas J; Smith, Gregory; Charbeneau, Michelle; Sohn, Euijung; Bienkowski, mary; Wong, Ivan; Meitzler, Allen H

    2008-01-01

    ...) plates for the purpose of crack detection is presented. The amplitudes of the vibrational modes undamaged plates are compared to the vibrational mode amplitudes of damaged plates and are shown to be clearly different...

  20. Detection of the incipient oxidation of coal by petrographic techniques

    CSIR Research Space (South Africa)

    Kruszewska, KJ

    1996-05-01

    Full Text Available Two petrographic methods, namely long-wave fluorescence intensity measurements and a vitrinite elasticity index were developed and used to detect incipient oxidation in coals subjected to simulated weathering conditions. The two methods are based...

  1. Development of detection techniques for the Swedish noble gas sampler

    Energy Technology Data Exchange (ETDEWEB)

    Ringbom, A

    1998-11-01

    A short review on the radioactive properties of noble gas isotopes relevant for monitoring of nuclear activities is given, together with a brief discussion of the existing systems for detection of radioactive noble gases. A 4{pi} detection system to be used in the automatic version of the Swedish noble gas sampling device is described. Monte Carlo calculations of the total gamma and beta efficiency for different detector designs have been performed, together with estimates of the resulting minimum detectable concentration (MDC). The estimated MDC values for detection of the {sup 133g}Xe 81 keV and the {sup 135g}Xe 250 keV gamma lines are around 0.3 mBq/m{sup 3} in both cases. This is a factor of three lower than the detection limit required for a sampling station in the Comprehensive Nuclear-Test-Ban Treaty monitoring network. The possibility to modify the system to detect {sup 85}Kr is also discussed 27 refs, 13 figs, 3 tabs

  2. Neutron techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    The way in which neutrons interact with matter such as slowing-down, diffusion, neutron absorption and moderation are described. The use of neutron techniques in industry, in moisture gages, level and interface measurements, the detection of blockages, boron analysis in ore feedstock and industrial radiography are discussed. (author)

  3. Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

    Science.gov (United States)

    Saturno, Jorge; Pöhlker, Christopher; Massabò, Dario; Brito, Joel; Carbone, Samara; Cheng, Yafang; Chi, Xuguang; Ditas, Florian; Hrabě de Angelis, Isabella; Morán-Zuloaga, Daniel; Pöhlker, Mira L.; Rizzo, Luciana V.; Walter, David; Wang, Qiaoqiao; Artaxo, Paulo; Prati, Paolo; Andreae, Meinrat O.

    2017-08-01

    Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP) data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA), which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June-September 2014). The mean absorption coefficient (at 637 nm) during this period was 1.8 ± 2.1 Mm-1, with a maximum of 15.9 Mm-1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption Ångström exponent (åABS) retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct åABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the åABS retrieved from offline MWAA measurements.

  4. A measurement-based technique for incipient anomaly detection

    KAUST Repository

    Harrou, Fouzi; Sun, Ying

    2016-01-01

    Fault detection is essential for safe operation of various engineering systems. Principal component analysis (PCA) has been widely used in monitoring highly correlated process variables. Conventional PCA-based methods, nevertheless, often fail to detect small or incipient faults. In this paper, we develop new PCA-based monitoring charts, combining PCA with multivariate memory control charts, such as the multivariate cumulative sum (MCUSUM) and multivariate exponentially weighted moving average (MEWMA) monitoring schemes. The multivariate control charts with memory are sensitive to small and moderate faults in the process mean, which significantly improves the performance of PCA methods and widen their applicability in practice. Using simulated data, we demonstrate that the proposed PCA-based MEWMA and MCUSUM control charts are more effective in detecting small shifts in the mean of the multivariate process variables, and outperform the conventional PCA-based monitoring charts. © 2015 IEEE.

  5. A novel hand-type detection technique with fingerprint sensor

    Science.gov (United States)

    Abe, Narishige; Shinzaki, Takashi

    2013-05-01

    In large-scale biometric authentication systems such as the US-Visit (USA), a 10-fingerprints scanner which simultaneously captures four fingerprints is used. In traditional systems, specific hand-types (left or right) are indicated, but it is difficult to detect hand-type due to the hand rotation and the opening and closing of fingers. In this paper, we evaluated features that were extracted from hand images (which were captured by a general optical scanner) that are considered to be effective for detecting hand-type. Furthermore, we extended the knowledge to real fingerprint images, and evaluated the accuracy with which it detects hand-type. We obtained an accuracy of about 80% with only three fingers (index, middle, ring finger).

  6. A measurement-based technique for incipient anomaly detection

    KAUST Repository

    Harrou, Fouzi

    2016-06-13

    Fault detection is essential for safe operation of various engineering systems. Principal component analysis (PCA) has been widely used in monitoring highly correlated process variables. Conventional PCA-based methods, nevertheless, often fail to detect small or incipient faults. In this paper, we develop new PCA-based monitoring charts, combining PCA with multivariate memory control charts, such as the multivariate cumulative sum (MCUSUM) and multivariate exponentially weighted moving average (MEWMA) monitoring schemes. The multivariate control charts with memory are sensitive to small and moderate faults in the process mean, which significantly improves the performance of PCA methods and widen their applicability in practice. Using simulated data, we demonstrate that the proposed PCA-based MEWMA and MCUSUM control charts are more effective in detecting small shifts in the mean of the multivariate process variables, and outperform the conventional PCA-based monitoring charts. © 2015 IEEE.

  7. Computational Intelligence based techniques for islanding detection of distributed generation in distribution network: A review

    International Nuclear Information System (INIS)

    Laghari, J.A.; Mokhlis, H.; Karimi, M.; Bakar, A.H.A.; Mohamad, Hasmaini

    2014-01-01

    Highlights: • Unintentional and intentional islanding, their causes, and solutions are presented. • Remote, passive, active and hybrid islanding detection techniques are discussed. • The limitation of these techniques in accurately detect islanding are discussed. • Computational intelligence techniques ability in detecting islanding is discussed. • Review of ANN, fuzzy logic control, ANFIS, Decision tree techniques is provided. - Abstract: Accurate and fast islanding detection of distributed generation is highly important for its successful operation in distribution networks. Up to now, various islanding detection technique based on communication, passive, active and hybrid methods have been proposed. However, each technique suffers from certain demerits that cause inaccuracies in islanding detection. Computational intelligence based techniques, due to their robustness and flexibility in dealing with complex nonlinear systems, is an option that might solve this problem. This paper aims to provide a comprehensive review of computational intelligence based techniques applied for islanding detection of distributed generation. Moreover, the paper compares the accuracies of computational intelligence based techniques over existing techniques to provide a handful of information for industries and utility researchers to determine the best method for their respective system

  8. Generation and detection technique of laser-ultrasonic

    International Nuclear Information System (INIS)

    Dho, Sang Whoe; Lee, Seung Seok

    1999-01-01

    A number of physical processes may take place when a solid surface is illuminated by a pulse laser. At lower power region these include heating, the generation of thermal waves, elastic waves (ultrasound). At higher powers, material may be ablated from the surface and a plasma formed, while in the sample there may be melting, plastic deformation and even the formation of cracks. In this letter we consider the generation techniques of laser-ultrasonic il all possible state. And we consider the measurement technique of laser-generated ultrasound based on the optical method.

  9. A Hybrid Islanding Detection Technique Using Average Rate of Voltage Change and Real Power Shift

    DEFF Research Database (Denmark)

    Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte

    2009-01-01

    The mainly used islanding detection techniques may be classified as active and passive techniques. Passive techniques don't perturb the system but they have larger nondetection znes, whereas active techniques have smaller nondetection zones but they perturb the system. In this paper, a new hybrid...... technique is proposed to solve this problem. An average rate of voltage change (passive technique) has been used to initiate a real power shift (active technique), which changes the eal power of distributed generation (DG), when the passive technique cannot have a clear discrimination between islanding...

  10. SQLdefend: An automated detection and prevention technique for ...

    African Journals Online (AJOL)

    SQL injection attacks (SQLIAs), one of the most foremost threats to Web applications is an attacking technique in which specially crafted input string result in illegal queries to a database. An SQL injection attack target interactive Web applications that employ database services. In this paper, we propose SQLDefend as a ...

  11. Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2016-08-01

    Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Using molecular techniques for rapid detection of Salmonella ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-02-01

    Feb 1, 2010 ... A total of 152 samples of chicken and chicken products ... detection of Salmonella species in the collected field samples ... that 16 million new cases of typhoid fever occur each ... vative methods for the rapid identification of Salmonella ... saved for the PCR-Non Selective test (PCR-NS) and 1 ml of the.

  13. A robust and fast generic voltage sag detection technique

    DEFF Research Database (Denmark)

    L. Dantas, Joacillo; Lima, Francisco Kleber A.; Branco, Carlos Gustavo C.

    2015-01-01

    In this paper, a fast and robust voltage sag detection algorithm, named VPS2D, is introduced. Using the DSOGI, the algorithm creates a virtual positive sequence voltage and monitories the fundamental voltage component of each phase. After calculating the aggregate value in the o:;3-reference fram...

  14. Signal Detection Framework Using Semantic Text Mining Techniques

    Science.gov (United States)

    Sudarsan, Sithu D.

    2009-01-01

    Signal detection is a challenging task for regulatory and intelligence agencies. Subject matter experts in those agencies analyze documents, generally containing narrative text in a time bound manner for signals by identification, evaluation and confirmation, leading to follow-up action e.g., recalling a defective product or public advisory for…

  15. Evaluation of the detection techniques of toxigenic Aspergillus isolates

    African Journals Online (AJOL)

    Aflatoxins are difuranocoumarin derivatives produced by some Aspergillus species through a polyketide pathway. Mycotoxins are considered hazardous and there is a need for accurate detection of each toxin. Several screening methods for direct visual determination of aflatoxins and ochratoxin A (OTA) production have ...

  16. Detecting Newcastle disease virus in combination of RT-PCR with red blood cell absorption

    Directory of Open Access Journals (Sweden)

    Liu Chengqian

    2011-05-01

    Full Text Available Abstract Reverse transcription-polymerase chain reaction (RT-PCR has limited sensitivity when treating complicated samples, such as feces, waste-water in farms, and nucleic acids, protein rich tissue samples, all the factors may interfere with the sensitivity of PCR test or generate false results. In this study, we developed a sensitive RT-PCR, combination of red blood cell adsorption, for detecting Newcastle disease virus (NDV. One pair of primers which was highly homologous to three NDV pathotypes was designed according to the consensus nucleocapsid protein (NP gene sequence. To eliminate the interfere of microbes and toxic substances, we concentrated and purified NDV from varied samples utilizing the ability of NDV binding red blood cells (RBCs. The RT-PCR coupled with red blood cell adsorption was much more sensitive in comparison with regular RT-PCR. The approach could also be used to detect other viruses with the property of hemagglutination, such as influenza viruses.

  17. Detection of gastrointestinal cancer by elastic scattering and absorption spectroscopies with the Los Alamos Optical Biopsy System

    Energy Technology Data Exchange (ETDEWEB)

    Mourant, J.R.; Boyer, J.; Johnson, T.M.; Lacey, J.; Bigio, I.J. [Los Alamos National Lab., NM (United States); Bohorfoush, A. [Wisconsin Medical School, Milwaukee, WI (United States). Dept. of Gastroenterology; Mellow, M. [Univ. of Oklahoma Medical School, Oklahoma City, OK (United States). Dept. of Gastroenterology

    1995-03-01

    The Los Alamos National Laboratory has continued the development of the Optical Biopsy System (OBS) for noninvasive, real-time in situ diagnosis of tissue pathologies. In proceedings of earlier SPIE conferences we reported on clinical measurements in the bladder, and we report here on recent results of clinical tests in the gastrointestinal tract. With the OBS, tissue pathologies are detected/diagnosed using spectral measurements of the elastic optical transport properties (scattering and absorption) of the tissue over a wide range of wavelengths. The use of elastic scattering as the key to optical tissue diagnostics in the OBS is based on the fact that many tissue pathologies, including a majority of cancer forms, exhibit significant architectural changes at the cellular and sub-cellular level. Since the cellular components that cause elastic scattering have dimensions typically on the order of visible to near-IR wavelengths, the elastic (Mie) scattering properties will be wavelength dependent. Thus, morphology and size changes can be expected to cause significant changes m an optical signature that is derived from the wavelength-dependence of elastic scattering. Additionally, the optical geometry of the OBS beneficially enhances its sensitivity for measuring absorption bands. The OBS employs a small fiber-optic probe that is amenable to use with any endoscope or catheter, or to direct surface examination, as well as interstitial needle insertion. Data acquistion/display time is <1 second.

  18. Multilayer Cloud Detection with the MODIS Near-Infrared Water Vapor Absorption Band

    Science.gov (United States)

    Wind, Galina; Platnick, Steven; King, Michael D.; Hubanks, Paul A,; Pavolonis, Michael J.; Heidinger, Andrew K.; Yang, Ping; Baum, Bryan A.

    2009-01-01

    Data Collection 5 processing for the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the NASA Earth Observing System EOS Terra and Aqua spacecraft includes an algorithm for detecting multilayered clouds in daytime. The main objective of this algorithm is to detect multilayered cloud scenes, specifically optically thin ice cloud overlying a lower-level water cloud, that presents difficulties for retrieving cloud effective radius using single layer plane-parallel cloud models. The algorithm uses the MODIS 0.94 micron water vapor band along with CO2 bands to obtain two above-cloud precipitable water retrievals, the difference of which, in conjunction with additional tests, provides a map of where multilayered clouds might potentially exist. The presence of a multilayered cloud results in a large difference in retrievals of above-cloud properties between the CO2 and the 0.94 micron methods. In this paper the MODIS multilayered cloud algorithm is described, results of using the algorithm over example scenes are shown, and global statistics for multilayered clouds as observed by MODIS are discussed. A theoretical study of the algorithm behavior for simulated multilayered clouds is also given. Results are compared to two other comparable passive imager methods. A set of standard cloudy atmospheric profiles developed during the course of this investigation is also presented. The results lead to the conclusion that the MODIS multilayer cloud detection algorithm has some skill in identifying multilayered clouds with different thermodynamic phases

  19. DETECTION OF CA II ABSORPTION BY A HIGH-VELOCITY CLOUD IN THE DIRECTION OF THE QUASAR PKS 0837-120

    NARCIS (Netherlands)

    ROBERTSON, JG; SCHWARZ, UJ; VANWOERDEN, H; MURRAY, JD; MORTON, DC; HULSBOSCH, ANM

    1991-01-01

    We present optical absorption spectroscopy of the Ca II K and H lines along the sight line to the quasar PKS 0837-120, which lies in the direction of a high-velocity cloud (HVC) detected in H I 21-cm emission at V(LSR) = + 105 km s-1. Our data show Ca II absorption due to the HVC as well as a lower

  20. HPLC-ESR techniques for detection of complex trapped radicals

    International Nuclear Information System (INIS)

    Tu Tiecheng; Dong Jirong; Lin Nianyun; Xie Leidong; Liu Rengzhong

    1992-01-01

    High performance liquid chromatography (HPLC) and ESR combined examination of radical species is an advanced techniques for separation and identification of complex radical species. At SRCL, Waters 990 HPLC has been used to separate the complex trapped radicals and Varian E-112 ESR spectrometer to record the spectra of single trapped radicals after HPLC separation. The advantages of the combined techniques are described as bellow: HPLC is used to separate the long-lived complex trapped radicals derived from reaction of short-lived radicals with spin trap. ESR spectra from single trapped radicals, obtained following HPLC separation of complex trapped radicals, are recorded one by one and well resolved. The structures of short-lived radicals can be inferred from the ESR spectra of the long-lived trapped radicals

  1. On detection and visualization techniques for cyber security situation awareness

    Science.gov (United States)

    Yu, Wei; Wei, Shixiao; Shen, Dan; Blowers, Misty; Blasch, Erik P.; Pham, Khanh D.; Chen, Genshe; Zhang, Hanlin; Lu, Chao

    2013-05-01

    Networking technologies are exponentially increasing to meet worldwide communication requirements. The rapid growth of network technologies and perversity of communications pose serious security issues. In this paper, we aim to developing an integrated network defense system with situation awareness capabilities to present the useful information for human analysts. In particular, we implement a prototypical system that includes both the distributed passive and active network sensors and traffic visualization features, such as 1D, 2D and 3D based network traffic displays. To effectively detect attacks, we also implement algorithms to transform real-world data of IP addresses into images and study the pattern of attacks and use both the discrete wavelet transform (DWT) based scheme and the statistical based scheme to detect attacks. Through an extensive simulation study, our data validate the effectiveness of our implemented defense system.

  2. Evaluation of ultrasound techniques for brain injury detection

    Science.gov (United States)

    Mobley, Joel; Kasili, Paul M.; Norton, Stephen J.; Vo-Dinh, Tuan

    1998-05-01

    In this work, we examine the physics underlying wave propagation in the head to evaluate various ultrasonic transducers for use in a brian injury detection device. The results of measurements of the attenuation coefficient and phase velocity for ultrasonic propagation in samples of brain tissue and skull bone from sheep are presented. The material properties are then used to investigate the propagation of ultrasonic pressure fields in the head. The ultrasound fields for three different transducers are calculated for propagation in a simulated brain/skull model. The model is constructed using speed-of-sound and mass density values of the two tissue types. The impact of the attenuation on the ultrasound fields is then examined. Finally, the relevant points drawn from these discussions are summarized. We hope to minimize the confounding effects of the skull by using sub-MHz ultrasound while maintaining the necessary temporal and spatial resolution to successfully detect injury in the brain.

  3. BENCHMARKING MACHINE LEARNING TECHNIQUES FOR SOFTWARE DEFECT DETECTION

    OpenAIRE

    Saiqa Aleem; Luiz Fernando Capretz; Faheem Ahmed

    2015-01-01

    Machine Learning approaches are good in solving problems that have less information. In most cases, the software domain problems characterize as a process of learning that depend on the various circumstances and changes accordingly. A predictive model is constructed by using machine learning approaches and classified them into defective and non-defective modules. Machine learning techniques help developers to retrieve useful information after the classification and enable them to analyse data...

  4. Survey of Insurance Fraud Detection Using Data Mining Techniques

    OpenAIRE

    Sithic, H. Lookman; Balasubramanian, T.

    2013-01-01

    With an increase in financial accounting fraud in the current economic scenario experienced, financial accounting fraud detection has become an emerging topics of great importance for academics, research and industries. Financial fraud is a deliberate act that is contrary to law, rule or policy with intent to obtain unauthorized financial benefit and intentional misstatements or omission of amounts by deceiving users of financial statements, especially investors and creditors. Data mining tec...

  5. Neutron-based techniques for detection of explosives and drugs

    Energy Technology Data Exchange (ETDEWEB)

    Kiraly, B.; Olah, L.; Csikai, J. E-mail: csikai@falcon.phys.klte.hu

    2001-06-01

    Systematic measurements were carried out on the possible use of elastically backscattered Pu-Be neutrons combined with the thermal neutron reflection method for the identification of land mines and illicit drugs via he detection of H, C, N, and O elements as their major constituents. While ur present results show that these methods are capable of indicating the anomalies in bulky materials and observation of the major elements, e termination of the exact atom fractions needs further investigation.

  6. Neutron-based techniques for detection of explosives and drugs

    CERN Document Server

    Kiraly, B; Csikai, J

    2001-01-01

    Systematic measurements were carried out on the possible use of elastically backscattered Pu-Be neutrons combined with the thermal neutron reflection method for the identification of land mines and illicit drugs via he detection of H, C, N, and O elements as their major constituents. While ur present results show that these methods are capable of indicating the anomalies in bulky materials and observation of the major elements, e termination of the exact atom fractions needs further investigation.

  7. New leak detection and location techniques for pipework and vessels

    International Nuclear Information System (INIS)

    Jax, P.; Leuker, W.

    1992-01-01

    The new monitoring systems are based on the moisture measurement with permeable sensor tubing or on acoustic measurement of leakage noise. An important characteristic is the capability to detect and locate leakages sensitively. Various physical dimensions are measured and accordingly there are differences in response time, sensitivity, accuracy of location and the ability to make statements about leakage rate. This paper considers in detail the basic principles, the technical system, areas of application and experience available. (orig.) [de

  8. A novel technique for detection efficiency determination of HPGe

    International Nuclear Information System (INIS)

    Tayyebi, Pouneh; Abbasi Davani, Fereydoun; Tabasi, Mohsen; Afarideh, Hossein

    2017-01-01

    In this work, we present an experimental method to determine the detection efficiency of HPGe when the reference source according to the geometry of interest is not accessible. We use known activity point sources (PS) of 152 Eu, 137 Cs, 241 Am and 133 Ba to find the detection efficiency for disc source (DS) geometry. It can be assumed that a DS consists of several PS's. Mapping the detector surface by means of 137 Cs PS shows that there is radial symmetry for detection efficiency vs. energy. Each radial distance on the detector surface contains some points, which can be considered as a PS. By selecting two points in two different radii and central point, the DS efficiency is obtained. To ensure that the method is correct, we measure the activity of a known activity DS considering DS efficiency obtained by PS's. The DS comprises 137 Cs, 133 Ba and 60 Co. The relative difference between the measured and the reported activity of DS in most energies is less than 5%. - Highlights: • Exact knowledge of the detector dimension is not necessary • There is no need to have standard source according to the sample • It is a simple method that can be done at any laboratories

  9. Employing image processing techniques for cancer detection using microarray images.

    Science.gov (United States)

    Dehghan Khalilabad, Nastaran; Hassanpour, Hamid

    2017-02-01

    Microarray technology is a powerful genomic tool for simultaneously studying and analyzing the behavior of thousands of genes. The analysis of images obtained from this technology plays a critical role in the detection and treatment of diseases. The aim of the current study is to develop an automated system for analyzing data from microarray images in order to detect cancerous cases. The proposed system consists of three main phases, namely image processing, data mining, and the detection of the disease. The image processing phase performs operations such as refining image rotation, gridding (locating genes) and extracting raw data from images the data mining includes normalizing the extracted data and selecting the more effective genes. Finally, via the extracted data, cancerous cell is recognized. To evaluate the performance of the proposed system, microarray database is employed which includes Breast cancer, Myeloid Leukemia and Lymphomas from the Stanford Microarray Database. The results indicate that the proposed system is able to identify the type of cancer from the data set with an accuracy of 95.45%, 94.11%, and 100%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Application of signal processing techniques for islanding detection of distributed generation in distribution network: A review

    International Nuclear Information System (INIS)

    Raza, Safdar; Mokhlis, Hazlie; Arof, Hamzah; Laghari, J.A.; Wang, Li

    2015-01-01

    Highlights: • Pros & cons of conventional islanding detection techniques (IDTs) are discussed. • Signal processing techniques (SPTs) ability in detecting islanding is discussed. • SPTs ability in improving performance of passive techniques are discussed. • Fourier, s-transform, wavelet, HHT & tt-transform based IDTs are reviewed. • Intelligent classifiers (ANN, ANFIS, Fuzzy, SVM) application in SPT are discussed. - Abstract: High penetration of distributed generation resources (DGR) in distribution network provides many benefits in terms of high power quality, efficiency, and low carbon emissions in power system. However, efficient islanding detection and immediate disconnection of DGR is critical in order to avoid equipment damage, grid protection interference, and personnel safety hazards. Islanding detection techniques are mainly classified into remote, passive, active, and hybrid techniques. From these, passive techniques are more advantageous due to lower power quality degradation, lower cost, and widespread usage by power utilities. However, the main limitations of these techniques are that they possess a large non detection zones and require threshold setting. Various signal processing techniques and intelligent classifiers have been used to overcome the limitations of passive islanding. Signal processing techniques, in particular, are adopted due to their versatility, stability, cost effectiveness, and ease of modification. This paper presents a comprehensive overview of signal processing techniques used to improve common passive islanding detection techniques. A performance comparison between the signal processing based islanding detection techniques with existing techniques are also provided. Finally, this paper outlines the relative advantages and limitations of the signal processing techniques in order to provide basic guidelines for researchers and field engineers in determining the best method for their system

  11. Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

    Directory of Open Access Journals (Sweden)

    J. Saturno

    2017-08-01

    Full Text Available Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA, which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June–September 2014. The mean absorption coefficient (at 637 nm during this period was 1.8 ± 2.1 Mm−1, with a maximum of 15.9 Mm−1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption Ångström exponent (åABS retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct åABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the åABS retrieved from offline MWAA measurements.

  12. DETECTING THE WARM-HOT INTERGALACTIC MEDIUM THROUGH X-RAY ABSORPTION LINES

    International Nuclear Information System (INIS)

    Yao Yangsen; Shull, J. Michael; Cash, Webster; Wang, Q. Daniel

    2012-01-01

    The warm-hot intergalactic medium (WHIM) at temperatures 10 5 -10 7 K is believed to contain 30%-50% of the baryons in the local universe. However, all current X-ray detections of the WHIM at redshifts z > 0 are of low statistical significance (∼ Ovii ∼10 15 cm -2 (corresponding to an equivalent width of 2.5 mÅ for a Doppler velocity of 50 km s –1 ) at ∼> 3σ significance level. The simulation results also suggest that it would take >60 Ms for Chandra and 140 Ms for XMM-Newton to measure the N Ovii at ≥4σ from a spectrum of a background QSO with flux of ∼0.2 mCrab (1 Crab = 2 × 10 –8 erg s –1 cm –2 at 0.5-2 keV). Future X-ray spectrographs need to be equipped with spectral resolution R ∼ 4000 and effective area A ≥ 100 cm 2 to accomplish the similar constraints with an exposure time of ∼2 Ms and would require ∼11 Ms to survey the 15 QSOs with flux ∼> 0.2 mCrab along which clear intergalactic O VI absorbers have been detected.

  13. An Analysis of Pre-Infection Detection Techniques for Botnets and other Malware

    OpenAIRE

    Graham, Mark; Winckles, Adrian

    2014-01-01

    Traditional techniques for detecting malware, such as viruses, worms and rootkits, rely on identifying virus-specific signature definitions within network traffic, applications or memory. Because a sample of malware is required to define an attack signature, signature detection has drawbacks when accounting for malware code mutation, has limited use in zero-day protection and is a post-infection technique requiring malware to be present on a device in order to be detected. \\ud A malicious bot...

  14. Electrical discharge in gases: a technique for detecting metal anomalies

    International Nuclear Information System (INIS)

    Lord, D.E.

    1979-01-01

    Optical ionization effects in gases appear to be very sensitive indicators of nonuniformities caused by contamination, deformation, and other factors affecting a metal surface. These optical effects are influenced by surface electron emission, which is influenced in turn by the chemical, metallurgical, and mechanical condition of the metal surface. Based on these effects, a general technique for inspection of critical parts that is fast, inexpensive, nondestructive, and not limited by size or geometry is presented. Ionization effects that reveal nonuniformities and were recorded with standard photographic equipment are shown

  15. Defect detection in conducting materials using eddy current testing techniques

    Directory of Open Access Journals (Sweden)

    Brauer Hartmut

    2014-01-01

    Full Text Available Lorentz force eddy current testing (LET is a novel nondestructive testing technique which can be applied preferably to the identification of internal defects in nonmagnetic moving conductors. The LET is compared (similar testing conditions with the classical eddy current testing (ECT. Numerical FEM simulations have been performed to analyze the measurements as well as the identification of internal defects in nonmagnetic conductors. The results are compared with measurements to test the feasibility of defect identification. Finally, the use of LET measurements to estimate of the electrical conductors under test are described as well.

  16. Detection of Irradiated Food using Photostimulated Luminescence (PSL) Technique

    International Nuclear Information System (INIS)

    Foziah Ali; Ros Anita Ahmad Ramli; Zainab Harun; Zainon Othman

    2015-01-01

    The Photostimulated luminescence (PSL) method may in principles be applied to detect irradiation of any foods which contain mineral debris, especially silicates mineral and bio inorganic materials such as calcite, which originate from shells or skeleton. These materials store energy in charge carriers trapped at structural interstitial or impurities site. When exposed to ionizing radiation optical stimulation of minerals release charges carriers. In PSL measurements, whole samples or a mixture of organic and inorganic materials can be used. The finding of this study will be useful to facilitate control of food irradiation application in Malaysia. (author)

  17. Detecting Molecular Properties by Various Laser-Based Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hsin, Tse-Ming [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Four different laser-based techniques were applied to study physical and chemical characteristics of biomolecules and dye molecules. These techniques are liole burning spectroscopy, single molecule spectroscopy, time-resolved coherent anti-Stokes Raman spectroscopy and laser-induced fluorescence microscopy. Results from hole burning and single molecule spectroscopy suggested that two antenna states (C708 & C714) of photosystem I from cyanobacterium Synechocystis PCC 6803 are connected by effective energy transfer and the corresponding energy transfer time is ~6 ps. In addition, results from hole burning spectroscopy indicated that the chlorophyll dimer of the C714 state has a large distribution of the dimer geometry. Direct observation of vibrational peaks and evolution of coumarin 153 in the electronic excited state was demonstrated by using the fs/ps CARS, a variation of time-resolved coherent anti-Stokes Raman spectroscopy. In three different solvents, methanol, acetonitrile, and butanol, a vibration peak related to the stretch of the carbonyl group exhibits different relaxation dynamics. Laser-induced fluorescence microscopy, along with the biomimetic containers-liposomes, allows the measurement of the enzymatic activity of individual alkaline phosphatase from bovine intestinal mucosa without potential interferences from glass surfaces. The result showed a wide distribution of the enzyme reactivity. Protein structural variation is one of the major reasons that are responsible for this highly heterogeneous behavior.

  18. Detection of special nuclear materials with the associate particle technique

    International Nuclear Information System (INIS)

    Carasco, Cédric; Deyglun, Clément; Pérot, Bertrand; Eléon, Cyrille; Normand, Stéphane; Sannié, Guillaume; Boudergui, Karim; Corre, Gwenolé; Konzdrasovs, Vladimir; Pras, Philippe

    2013-01-01

    In the frame of the French trans-governmental R and D program against chemical, biological, radiological, nuclear and explosives (CBRN-E) threats, CEA is studying the detection of Special Nuclear Materials (SNM) by neutron interrogation with fast neutrons produced by an associated particle sealed tube neutron generator. The deuterium-tritium fusion reaction produces an alpha particle and a 14 MeV neutron almost back to back, allowing tagging neutron emission both in time and direction with an alpha particle position-sensitive sensor embedded in the generator. Fission prompt neutrons and gamma rays induced by tagged neutrons which are tagged by an alpha particle are detected in coincidence with plastic scintillators. This paper presents numerical simulations performed with the MCNP-PoliMi Monte Carlo computer code and with post processing software developed with the ROOT data analysis package. False coincidences due to neutron and photon scattering between adjacent detectors (cross talk) are filtered out to increase the selectivity between nuclear and benign materials. Accidental coincidences, which are not correlated to an alpha particle, are also taken into account in the numerical model, as well as counting statistics, and the time-energy resolution of the data acquisition system. Such realistic calculations show that relevant quantities of SNM (few kg) can be distinguished from cargo and shielding materials in 10 min acquisitions. First laboratory tests of the system under development in CEA laboratories are also presented.

  19. Using Nuclear Techniques to Detect Helicobacter Pylori Infection

    International Nuclear Information System (INIS)

    Slater, Christine

    2014-01-01

    Helicobacter pylori (H. pylori) is present in all countries the world over. More than 50% of the world’s population harbour H. pylori in their upper gastrointestinal tract. It can negatively influence nutrition by affecting the uptake of iron and zinc and by increasing susceptibility to diarrhoeal disease. Beyond that, H. pylori is also a major cause of stomach diseases like chronic gastritis, and elevates the risk of developing stomach cancer. The carbon-13 urea breath test is a quick and non-invasive diagnostic test to detect the presence of H. pylori. The patient drinks urea labelled with stable carbon isotopes ( 13 C) that is dissolved in orange juice or citric acid to make sure it coats the entire surface of the stomach, thereby improving the test’s accuracy. If H. pylori is present, it metabolizes the urea and, after 30 minutes, produces carbon dioxide labelled with the stable carbon isotope ( 13 CO 2 ), which can be detected in the breath analysis

  20. Effective approach toward Intrusion Detection System using data mining techniques

    Directory of Open Access Journals (Sweden)

    G.V. Nadiammai

    2014-03-01

    Full Text Available With the tremendous growth of the usage of computers over network and development in application running on various platform captures the attention toward network security. This paradigm exploits security vulnerabilities on all computer systems that are technically difficult and expensive to solve. Hence intrusion is used as a key to compromise the integrity, availability and confidentiality of a computer resource. The Intrusion Detection System (IDS plays a vital role in detecting anomalies and attacks in the network. In this work, data mining concept is integrated with an IDS to identify the relevant, hidden data of interest for the user effectively and with less execution time. Four issues such as Classification of Data, High Level of Human Interaction, Lack of Labeled Data, and Effectiveness of Distributed Denial of Service Attack are being solved using the proposed algorithms like EDADT algorithm, Hybrid IDS model, Semi-Supervised Approach and Varying HOPERAA Algorithm respectively. Our proposed algorithm has been tested using KDD Cup dataset. All the proposed algorithm shows better accuracy and reduced false alarm rate when compared with existing algorithms.

  1. New techniques for the detection and capture of micrometeoroids

    International Nuclear Information System (INIS)

    Wolfe, J.H.

    1987-01-01

    In order to understand the origin and distribution of the biogenic elements and their compounds in the solar system, it will be necessary to study materials from many classes of objects. Chemical, elemental, and isotopic measurements of returned samples of comets, asteroids, and possibly extra-solar system dust clouds would provide information on a particularly important class: primitive objects. Extraterrestrial micron-sized particles in the vicinity of Earth are one source of such materials that might otherwise be inaccessible. The Space Station appears to be an eminently suitable platform from which to collect and detect these various particles. The primary challenge, however, is to collect intact, uncontaminated particles which will be encountered at tens of kilometers per seconds. A concept for a micrometeoroid detector that could be deployed from the Space Station was developed which uses a large area detector plate implanted with acoustic transducers. When an impact event occurs, the resulting signal is subjected to spectral analysis providing positive detection, momentum information, and angle of incidence. The primary advantage of this detector is the large area which increases the probability of measuring events. A concept of a nondestuctive micrometeoroid collector for use from a Space Station was also developed. The collector utilizes input port charging of the incoming particle followed by staged high voltage deceleration for nondestructive capture. Low velocity particles (local contamination) would be rejected due to insufficient energy and only uncontaminated micrometeoroids would be collected

  2. New techniques for the detection and capture of micrometeoroids

    Science.gov (United States)

    Wolfe, J. H.

    1987-11-01

    In order to understand the origin and distribution of the biogenic elements and their compounds in the solar system, it will be necessary to study materials from many classes of objects. Chemical, elemental, and isotopic measurements of returned samples of comets, asteroids, and possibly extra-solar system dust clouds would provide information on a particularly important class: primitive objects. Extraterrestrial micron-sized particles in the vicinity of Earth are one source of such materials that might otherwise be inaccessible. The Space Station appears to be an eminently suitable platform from which to collect and detect these various particles. The primary challenge, however, is to collect intact, uncontaminated particles which will be encountered at tens of kilometers per seconds. A concept for a micrometeoroid detector that could be deployed from the Space Station was developed which uses a large area detector plate implanted with acoustic transducers. When an impact event occurs, the resulting signal is subjected to spectral analysis providing positive detection, momentum information, and angle of incidence. The primary advantage of this detector is the large area which increases the probability of measuring events. A concept of a nondestuctive micrometeoroid collector for use from a Space Station was also developed. The collector utilizes input port charging of the incoming particle followed by staged high voltage deceleration for nondestructive capture. Low velocity particles (local contamination) would be rejected due to insufficient energy and only uncontaminated micrometeoroids would be collected.

  3. Imaging monitoring techniques applications in the transient gratings detection

    Science.gov (United States)

    Zhao, Qing-ming

    2009-07-01

    Experimental studies of Degenerate four-wave mixing (DFWM) in iodine vapor at atmospheric pressure and 0℃ and 25℃ are reported. The Laser-induced grating (LIG) studies are carried out by generating the thermal grating using a pulsed, narrow bandwidth, dye laser .A new image processing system for detecting forward DFWM spectroscopy on iodine vapor is reported. This system is composed of CCD camera, imaging processing card and the related software. With the help of the detecting system, phase matching can be easily achieved in the optical arrangement by crossing the two pumps and the probe as diagonals linking opposite corners of a rectangular box ,and providing a way to position the PhotoMultiplier Tube (PMT) . Also it is practical to know the effect of the pointing stability on the optical path by monitoring facula changing with the laser beam pointing and disturbs of the environment. Finally the effects of Photostability of dye laser on the ration of signal to noise in DFWM using forward geometries have been investigated in iodine vapor. This system makes it feasible that the potential application of FG-DFWM is used as a diagnostic tool in combustion research and environment monitoring.

  4. Detection and Processing Techniques of FECG Signal for Fetal Monitoring

    Directory of Open Access Journals (Sweden)

    Hasan MA

    2009-03-01

    Full Text Available Abstract Fetal electrocardiogram (FECG signal contains potentially precise information that could assist clinicians in making more appropriate and timely decisions during labor. The ultimate reason for the interest in FECG signal analysis is in clinical diagnosis and biomedical applications. The extraction and detection of the FECG signal from composite abdominal signals with powerful and advance methodologies are becoming very important requirements in fetal monitoring. The purpose of this review paper is to illustrate the various methodologies and developed algorithms on FECG signal detection and analysis to provide efficient and effective ways of understanding the FECG signal and its nature for fetal monitoring. A comparative study has been carried out to show the performance and accuracy of various methods of FECG signal analysis for fetal monitoring. Finally, this paper further focused some of the hardware implementations using electrical signals for monitoring the fetal heart rate. This paper opens up a passage for researchers, physicians, and end users to advocate an excellent understanding of FECG signal and its analysis procedures for fetal heart rate monitoring system.

  5. Study of the texture of porous solids using a technique of {gamma} ray absorption; Application de l'absorption du rayonnement {gamma} a l'etude de la texture des solides poreux

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, M. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-01-01

    A technique, which enables us to measure locally total porosity, open porosity and pore size distribution is developed. The total porosity is calculated from the bulk density. A gamma absorption gauge is set up fitted with a Cs137 source. This enables the determination of the density by layers of carbonaceous samples in a practically automatic way. By taking adequate precautions it is possible to obtain the density with a maximum error {delta}{rho} {<=} 0,005 g/cm{sup 3}. The open porosity is evaluated by the absorption method after impregnation with bromoform. A new mercury porosimeter is developed using the absorption probe for the measurement of mercury infiltrated into the porous sample. Due to the localized character of exploration by this technique, the variations of porous texture in a heterogeneous sample can be studied. Used as a classical porosimeter, in the case of homogeneous samples, this apparatus is capable of exploring the equivalent diameters of pores between 500 {mu} and 0.14 {mu} with a maximum error {delta}P {<=} 0.002. The possibility of exploration of heterogeneous samples, with the facility of determination of porosities due to macro-pores combined with the non-limiting character of the method in the field of high pressures differentiates this apparatus from all the porosimeters of former conception. Examples of utilization of this technique in the case of graphite-gas reactions are presented. (author) [French] On a developpe une technique permettant la mesure localisee de la porosite totale, de la porosite ouverte et de la repartition de la taille de pores. La porosite totale est calculee a partir de la densite apparente. On a mis au point une jauge d'absorption du rayonnement gamma munie d'une source de Cs137. Celle-ci nous a permis de determiner la densite par couches d'echantillons cylindriques carbones d'une facon pratiquement automatique. En prenant les precautions adequates, il est possible d'obtenir la densite

  6. Study of the texture of porous solids using a technique of {gamma} ray absorption; Application de l'absorption du rayonnement {gamma} a l'etude de la texture des solides poreux

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, M [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-01-01

    A technique, which enables us to measure locally total porosity, open porosity and pore size distribution is developed. The total porosity is calculated from the bulk density. A gamma absorption gauge is set up fitted with a Cs137 source. This enables the determination of the density by layers of carbonaceous samples in a practically automatic way. By taking adequate precautions it is possible to obtain the density with a maximum error {delta}{rho} {<=} 0,005 g/cm{sup 3}. The open porosity is evaluated by the absorption method after impregnation with bromoform. A new mercury porosimeter is developed using the absorption probe for the measurement of mercury infiltrated into the porous sample. Due to the localized character of exploration by this technique, the variations of porous texture in a heterogeneous sample can be studied. Used as a classical porosimeter, in the case of homogeneous samples, this apparatus is capable of exploring the equivalent diameters of pores between 500 {mu} and 0.14 {mu} with a maximum error {delta}P {<=} 0.002. The possibility of exploration of heterogeneous samples, with the facility of determination of porosities due to macro-pores combined with the non-limiting character of the method in the field of high pressures differentiates this apparatus from all the porosimeters of former conception. Examples of utilization of this technique in the case of graphite-gas reactions are presented. (author) [French] On a developpe une technique permettant la mesure localisee de la porosite totale, de la porosite ouverte et de la repartition de la taille de pores. La porosite totale est calculee a partir de la densite apparente. On a mis au point une jauge d'absorption du rayonnement gamma munie d'une source de Cs137. Celle-ci nous a permis de determiner la densite par couches d'echantillons cylindriques carbones d'une facon pratiquement automatique. En prenant les precautions adequates, il est possible d'obtenir la densite avec une erreur maximale

  7. Indirect fluorometric detection techniques on thin layer chromatography and effect of ultrasound on gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Yinfa, Ma.

    1990-12-10

    Thin-layer chromatography (TLC) is a broadly applicable separation technique. It offers many advantages over high performance liquid chromatography (HPLC), such as easily adapted for two-dimensional separation, for whole-column'' detection and for handling multiple samples, etc. However, due to its draggy development of detection techniques comparing with HPLC, TLC has not received the attention it deserves. Therefore, exploring new detection techniques is very important to the development of TLC. It is the principal of this dissertation to present a new detection method for TLC -- indirect fluorometric detection method. This detection technique is universal sensitive, nondestructive, and simple. This will be described in detail from Sections 1 through Section 5. Section 1 and 3 describe the indirect fluorometric detection of anions and nonelectrolytes in TLC. In Section 2, a detection method for cations based on fluorescence quenching of ethidium bromide is presented. In Section 4, a simple and interesting TLC experiment is designed, three different fluorescence detection principles are used for the determination of caffeine, saccharin and sodium benzoate in beverages. A laser-based indirect fluorometric detection technique in TLC is developed in Section 5. Section 6 is totally different from Sections 1 through 5. An ultrasonic effect on the separation of DNA fragments in agarose gel electrophoresis is investigated. 262 refs.

  8. Techniques for land use change detection using Landsat imagery

    Science.gov (United States)

    Angelici, G. L.; Bryant, N. A.; Friedman, S. Z.

    1977-01-01

    A variety of procedures were developed for the delineation of areas of land use change using Landsat Multispectral Scanner data and the generation of statistics revealing the nature of the changes involved (i.e., number of acres changed from rural to urban). Techniques of the Image Based Information System were utilized in all stages of the procedure, from logging the Landsat data and registering two frames of imagery, to extracting the changed areas and printing tabulations of land use change in acres. Two alternative methods of delineating land use change are presented while enumerating the steps of the entire process. The Houston, Texas urban area, and the Orlando, Florida urban area, are used as illustrative examples of various procedures.

  9. Techniques for the detection of photodesorbed negative ions

    International Nuclear Information System (INIS)

    Young, C.E.; Schweitzer, E.L.; Pellin, M.J.; Gruen, D.M.; Hurych, Z.; Soukiassian, P.; Bakshi, M.H.; Bommannavar, A.S.

    1987-01-01

    This paper reports the direct observation of H - ions released from a Cs-dosed W(100) crystal by photon-stimulated desorption (PSD). This study utilized the 3m toroidal grating monochromator beamline at the University of Wisconsin-Madison Synchrotron Radiation Center. The main technical problem to be overcome in such experiments is the large background from photoemitted electrons which dominate the weak anion signal by many orders of magnitude. The solution ultimately employed utilized both magnetic suppression of photoelectrons and time-of-flight (TOF) mass separation. No internal modifications to the basic cylindrical mirror analyzer (CMA) were required. We are not aware of any previous reports of the detection of negative ions released from surfaces via photon bombardment, with the exception of high flux laser experiments, in which plasma formation is involved in the ionization process. 16 refs., 3 figs

  10. Neutron-based techniques for detection of explosives and drugs

    International Nuclear Information System (INIS)

    Kiraly, B.; Olah, L.; Csikai, G.J.

    2000-01-01

    Neutron reflection, scattering and transmission methods combined with the detection of characteristic gamma rays have an increasing role in the identification of hidden explosives, illicit drugs and other contraband materials. There are about 100 million land mines buried in some 70 countries. Among the abandoned anti-personnel land mines (APL) certain types have low mass (about 100 g) and contain little or no metal. Therefore, these plastic APL cannot be detected by the usual metal detectors. The IAEA Physics Section has organized a CRP in 1999 for the development of novel methods in order to speed up the removing process of APL. The transportation of illicit drugs has shown an increasing trend during the last decade. Developments of fast, non-destructive interrogation methods are required for the inspection of cargo containers, trucks and airline baggage. The major constituents of plastic APL and drugs are H, C, N and O which can be identified by the different neutron interactions. The atom fractions of these elements, in particular the C/O, C/N and C/H ratios, are quite different for drugs and explosives as compared to other materials used to hide them. Recently, we have carried out systematic measurements and calculations on the neutron fields from the 9 Be(d,n), 2 H(d,n), 252 Cf and Pu-Be sources passing through different bulky samples, on the possible use of elastically backscattered Pu-Be neutrons in elemental analysis and on the advantages and limitations of the thermal neutron reflection method in the identification of land mines and illicit drugs. The measured spectral shapes of neutrons were compared with the calculated results using the MCNP-4A and MCNP-4B codes. (author)

  11. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    Science.gov (United States)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    Projections of the atomic structure around Nb atoms in a LiNbO3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples. PMID:21997909

  12. Optimized digital filtering techniques for radiation detection with HPGe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Salathe, Marco, E-mail: marco.salathe@mpi-hd.mpg.de; Kihm, Thomas, E-mail: mizzi@mpi-hd.mpg.de

    2016-02-01

    This paper describes state-of-the-art digital filtering techniques that are part of GEANA, an automatic data analysis software used for the GERDA experiment. The discussed filters include a novel, nonlinear correction method for ballistic deficits, which is combined with one of three shaping filters: a pseudo-Gaussian, a modified trapezoidal, or a modified cusp filter. The performance of the filters is demonstrated with a 762 g Broad Energy Germanium (BEGe) detector, produced by Canberra, that measures γ-ray lines from radioactive sources in an energy range between 59.5 and 2614.5 keV. At 1332.5 keV, together with the ballistic deficit correction method, all filters produce a comparable energy resolution of ~1.61 keV FWHM. This value is superior to those measured by the manufacturer and those found in publications with detectors of a similar design and mass. At 59.5 keV, the modified cusp filter without a ballistic deficit correction produced the best result, with an energy resolution of 0.46 keV. It is observed that the loss in resolution by using a constant shaping time over the entire energy range is small when using the ballistic deficit correction method.

  13. Absorption-line detections of 105-106 K gas in spiral-rich groups of galaxies

    International Nuclear Information System (INIS)

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Syphers, David; Yamamoto, H.; Shull, J. Michael; Green, James C.; Froning, Cynthia; Savage, Blair D.; Wakker, Bart; Kim, Tae-Sun; Ryan-Weber, Emma V.; Kacprzak, Glenn G.

    2014-01-01

    Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper, these far-UV spectra were used to discover 14 'warm' (T ≥ 10 5 K) absorbers using a combination of broad Lyα and broad O VI absorptions. A reanalysis of a few of this new class of absorbers using slightly relaxed fitting criteria finds as many as 20 warm absorbers could be present in this sample. A shallow, wide spectroscopic galaxy redshift survey has been conducted around these sight lines to investigate the warm absorber environment, which is found to be spiral-rich groups or cluster outskirts with radial velocity dispersions σ = 250-750 km s –1 . While 2σ evidence is presented favoring the hypothesis that these absorptions are associated with the galaxy groups and not with the individual, nearest galaxies, this evidence has considerable systematic uncertainties and is based on a small sample size so it is not entirely conclusive. If the associations are with galaxy groups, the observed frequency of warm absorbers (dN/dz = 3.5-5 per unit redshift) requires them to be very extended as an ensemble on the sky (∼1 Mpc in radius at high covering factor). Most likely these warm absorbers are interface gas clouds whose presence implies the existence of a hotter (T ∼ 10 6.5 K), diffuse, and probably very massive (>10 11 M ☉ ) intra-group medium which has yet to be detected directly.

  14. Exploring machine-learning-based control plane intrusion detection techniques in software defined optical networks

    Science.gov (United States)

    Zhang, Huibin; Wang, Yuqiao; Chen, Haoran; Zhao, Yongli; Zhang, Jie

    2017-12-01

    In software defined optical networks (SDON), the centralized control plane may encounter numerous intrusion threatens which compromise the security level of provisioned services. In this paper, the issue of control plane security is studied and two machine-learning-based control plane intrusion detection techniques are proposed for SDON with properly selected features such as bandwidth, route length, etc. We validate the feasibility and efficiency of the proposed techniques by simulations. Results show an accuracy of 83% for intrusion detection can be achieved with the proposed machine-learning-based control plane intrusion detection techniques.

  15. Detection of multidrug resistance using molecular nuclear technique

    International Nuclear Information System (INIS)

    Lee, Jae Tae; Ahn, Byeong Cheol

    2004-01-01

    Although the outcome of cancer patients after cytotoxic chemotherapy is related diverse mechanisms, multidrug resistance (MDR) for chemotherapeutic drugs due to cellular P-glycoprotein (Pgp) or multidrug-resistance associated protein (MRP) is most important factor in the chemotherapy failure to cancer. A large number of pharmacologic compounds, including verapamil, quinidine, tamoxifen, cyclosporin A and quinolone derivatives have been reported to overcome MDR. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are available for the detection of Pgp and MRP-mediated transporter. 99 m-Tc-MIBI and other 99 m-Tc-radiopharmaceuticals are substrates for Pgp and MRP, and have been used in clinical studies for tumor imaging, and to visualize blockade of Pgp-mediated transport after modulation of Pgp pump. Colchicine, verapamil and daunorubicin labeled with 11 C have been evaluated for the quantification of Pgp-mediated transport with PET in vivo and reported to be feasible substrates with which to image Pgp function in tumors. Leukotrienes are specific substrates for MRP and N-( 11 C)acetyl-leukotriene E4 provides an opportunity to study MRP function non-invasively in vivo. SPECT and PET pharmaceuticals have successfully used to evaluate pharmacologic effects of MDR modulators. Imaging of MDR and reversal of MDR with bioluminescence in a living animal is also evaluated for future clinical trial. We have described recent advances in molecular imaging of MDR and reviewed recent publications regarding feasibility of SPECT and PET imaging to study the functionality of MDR transporters in vivo

  16. Detection of mechanical damage using the magnetic flux leakage technique

    International Nuclear Information System (INIS)

    Clapham, L.; Babbar, V.; Byrne, J.

    2007-01-01

    Since magnetism is strongly stress dependent, Magnetic Flux Leakage (MFL) inspection tools have the potential to locate and characterize mechanical damage in pipelines. However, MFL application to mechanical damage detection faces hurdles which make signal interpretation problematic: 1) the MFL signal is a superposition of geometrical and stress effects; 2) the stress distribution around a mechanically damaged region is very complex, consisting of plastic deformation and residual (elastic) stresses; 3) the effect of stress on magnetic behaviour is not well understood. This paper summarizes recent results of experimental and modeling studies of MFL signals resulting from mechanical damage. In experimental studies, mechanical damage was simulated using a tool and die press to produce dents of varying depths in plate samples. MFL measurements were made before and after selective stress-relieving heat treatments. These annealing treatments enabled the stress and geometry components of the MFL signal to be separated. In general, geometry effects scale with dent depth and tend to dominate in deep dents, while stress contribution to the MFL signals is relatively constant and is more significant for shallow dents. The influence of other parameters such as flux density and topside/bottomside inspection was also quantified. In the finite element analysis work, stress was incorporated by modifying the magnetic permeability in the residual stress regions of the modeled dent. Both stress and geometry contributions to the MFL signal were examined separately. Despite using a number of simplifying assumptions, the modeled results matched the experimental results very closely, and were used to aid in interpretation of the MFL signals. (author)

  17. Double resonance capacitance spectroscopy (DORCAS): A new experimental technique for assignment of X-ray absorption peaks to surface sites of semiconductor

    CERN Document Server

    Ishii, M

    2003-01-01

    As a new microspectroscopy for semiconductor surface analysis using an X-ray beam, double resonance capacitance spectroscopy (DORCAS) is proposed. For a microscopic X-ray absorption measurement, a local capacitance change owing to X-ray induced emission of localized electrons is detected by a microprobe. The applied bias voltage V sub b dependence of the capacitance also provides information on the surface density of state. The resonance of the Fermi energy with a surface level by V sub b control makes possible the selection of the observable surface site in the X-ray absorption measurements, i.e. site-specific spectroscopy. The double resonance of the surface site selection (V sub b resonance) and the resonant X-ray absorption of the selected site (photon energy h nu resonance) enhances the capacitance signal. The DORCAS measurement of the GaAs surface shows correlation peaks at h nu=10.402 keV and V sub b =-0.4 V and h nu=10.429 keV and V sub b =+0.1 V, indicating that these resonant X-ray absorption peaks ...

  18. Quantitative analysis of the self-absorption and reemission effects on the emission spectrum of photoluminescence in right-angle excitation—detection configuration

    International Nuclear Information System (INIS)

    Wang Zhen-Hua; Wu Yu-E; Zhang Xin-Zheng; Yun Zhi-Qiang; Li Wei; Xu Jing-Jun

    2013-01-01

    A theoretical approach based on differential radiative transport is proposed to quantitatively analyze the self-absorption and reemission effects on the emission spectrum for right angle excitation—detection photoluminescence measurements, and the wavelength dependence of the reemission effect is taken into account. Simulations and experiments are performed using rhodamine 6G solutions in ethanol as model samples. It is shown that the self-absorption effect is the dominant effect on the detected spectrum by inducing pseudo red-shift and reducing total intensity; whereas the reemission effect partly compensates for signal decrease and also results in an apparent signal gain at the wavelengths without absorption. Both effects decrease with the decrease in the sample concentration and the propagation distance of the emission light inside the sample. We therefore suggest that diluted solutions are required for accurate photoluminescence spectrum measurements and photoluminescence-based measurements

  19. Biosensor technology for the detection of illegal drugs II: antibody development and detection techniques

    Science.gov (United States)

    Hilpert, Reinhold; Bauer, Christian; Binder, Florian; Grol, Michael; Hallermayer, Klaus; Josel, Hans-Peter; Klein, Christian; Maier, Josef; Makower, Alexander; Oberpriller, Helmut; Ritter, Josef

    1994-10-01

    In a joint project of Deutsche Aerospace, Boehringer Mannheim and the University of Potsdam portable devices for the detection of illegal drugs, based on biosensor technology, are being developed. The concept enrichment of the drug from the gas phase and detection by immunological means. This publication covers the development of specific antibodies and various detection procedures. Antibodies with a high affinity for cocaine have been developed with the aid of specially synthesized immunogens. A competitive detection procedure with biosensors based on optical grating couplers and applying particulate labels has been established, showing a lower detection limit of 10-10 mol/l for cocaine. Additionally, a combination of a displacement-immunoreactor and an enzymatically amplified electrode was investigated, which at present still suffers from insufficient sensitivity of the immunoreactor. An alternative, fleece-matrix based test procedure, where enrichment and detection steps are integrated in a single unit, is promising in terms of simplicity and sensitivity. A simple swab-test for the detection of cocaine at surfaces has been developed, which has a lower detection limit of about 10 ng and which can be performed within one minute.

  20. An energy kurtosis demodulation technique for signal denoising and bearing fault detection

    International Nuclear Information System (INIS)

    Wang, Wilson; Lee, Hewen

    2013-01-01

    Rolling element bearings are commonly used in rotary machinery. Reliable bearing fault detection techniques are very useful in industries for predictive maintenance operations. Bearing fault detection still remains a very challenging task especially when defects occur on rotating bearing components because the fault-related features are non-stationary in nature. In this work, an energy kurtosis demodulation (EKD) technique is proposed for bearing fault detection especially for non-stationary signature analysis. The proposed EKD technique firstly denoises the signal by using a maximum kurtosis deconvolution filter to counteract the effect of signal transmission path so as to highlight defect-associated impulses. Next, the denoised signal is modulated over several frequency bands; a novel signature integration strategy is proposed to enhance feature characteristics. The effectiveness of the proposed EKD fault detection technique is verified by a series of experimental tests corresponding to different bearing conditions. (paper)

  1. The close objects buffer : a sharp shadow detection technique for radiosity methods

    NARCIS (Netherlands)

    Telea, A.C.; Overveld, van C.W.A.M.

    1997-01-01

    Detecting sharp illumination variations such as shadow boundaries is an important problem for radiosity methods. Such illumination variations are captured using a nonuniform mesh that refines the areas exhibiting high illumination gradients. Nonuniform meshing techniques like discontinuity meshing

  2. The Close Objects Buffer : A Sharp Shadow Detection Technique for Radiosity Methods

    NARCIS (Netherlands)

    Telea, A.C.; Overveld, C.W.A.M. van

    1998-01-01

    Detecting sharp illumination variations such as shadow boundaries is an important problem for radiosity methods. Such illumination variations are captured using a nonuniform mesh that refines the areas exhibiting high illumination gradients. Nonuniform meshing techniques like discontinuity meshing

  3. Detection of Atmospheric Explosions at IMS Monitoring Stations using Infrasound Techniques

    National Research Council Canada - National Science Library

    Christie, Douglas R; Kennett, Brian L; Tarlowski, Chris

    2006-01-01

    Work is continuing on the development of infrasound techniques that can be used to improve detection, location and discrimination capability for atmospheric nuclear explosions at International Monitoring System (IMS...

  4. Determination of Pu Oxidation states in the HCl Media Using with UV-Visible Absorption Spectroscopic Techniques

    International Nuclear Information System (INIS)

    Lee, Myung Ho; Suh, Mu Yeol; Park, Kyoung Kyun; Park, Yeong Jae; Kim, Won Ho

    2006-01-01

    The spectroscopic characteristics of Pu (III, IV, V, VI) in the HCl media were investigated by measuring Pu oxidation states using a UV-Vis-NIR spectrophotometer (400-1200 nm) after adjusting Pu oxidation states with oxidation/reduction reagents. Pu in stock solution was reduced to Pu(III) with NH 2 OH · HCl, and oxidized to Pu(IV) and Pu(VI) with NaNO 2 and HCIO 4 , respectively. Also, Pu(V) was adjusted in the Pu(VI) solution with NH 2 OH · HCl. The major absorption peaks of Pu (IV) and Pu(III) were measured in the 470 nm and 600 nm, respectively. The major absorption peaks of Pu (VI) and Pu(V) were measured in the 830 nm and 1135 nm, respectively. There was not found to be significant changes of UV-V is absorption spectra for Pu(III), Pu(IV) and Pu(VI) with aging time, except that an unstable Pu(V) immediately reduced to Pu(III).

  5. Laser-based absorption spectroscopy as a technique for rapid in-line analysis of respired gas concentrations of O2 and CO2.

    Science.gov (United States)

    Cummings, Beth; Hamilton, Michelle L; Ciaffoni, Luca; Pragnell, Timothy R; Peverall, Rob; Ritchie, Grant A D; Hancock, Gus; Robbins, Peter A

    2011-07-01

    The use of sidestream analyzers for respired gas analysis is almost universal. However, they are not ideal for measurements of respiratory gas exchange because the analyses are both temporally dissociated from measurements of respiratory flow and also not generally conducted under the same physical conditions. This study explores the possibility of constructing an all optical, fast response, in-line breath analyzer for oxygen and carbon dioxide. Using direct absorption spectroscopy with a diode laser operating at a wavelength near 2 μm, measurements of expired carbon dioxide concentrations were obtained with an absolute limit of detection of 0.04% at a time resolution of 10 ms. Simultaneously, cavity enhanced absorption spectroscopy at a wavelength near 760 nm was employed to obtain measurements of expired oxygen concentrations with an absolute limit of detection of 0.26% at a time resolution of 10 ms. We conclude that laser-based absorption spectroscopy is a promising technology for in-line analysis of respired carbon dioxide and oxygen concentrations.

  6. Fluorescence hyperspectral imaging technique for foreign substance detection on fresh-cut lettuce.

    Science.gov (United States)

    Mo, Changyeun; Kim, Giyoung; Kim, Moon S; Lim, Jongguk; Cho, Hyunjeong; Barnaby, Jinyoung Yang; Cho, Byoung-Kwan

    2017-09-01

    Non-destructive methods based on fluorescence hyperspectral imaging (HSI) techniques were developed to detect worms on fresh-cut lettuce. The optimal wavebands for detecting the worms were investigated using the one-way ANOVA and correlation analyses. The worm detection imaging algorithms, RSI-I (492-626)/492 , provided a prediction accuracy of 99.0%. The fluorescence HSI techniques indicated that the spectral images with a pixel size of 1 × 1 mm had the best classification accuracy for worms. The overall results demonstrate that fluorescence HSI techniques have the potential to detect worms on fresh-cut lettuce. In the future, we will focus on developing a multi-spectral imaging system to detect foreign substances such as worms, slugs and earthworms on fresh-cut lettuce. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Criteria for assessing the quality of signal processing techniques for acoustic leak detection

    International Nuclear Information System (INIS)

    Prabhakar, R.; Singh, O.P.

    1990-01-01

    In this paper the criteria used in the first IAEA coordinated research programme to assess the quality of signal processing techniques for sodium boiling noise detection are highlighted. Signal processing techniques, using new features sensitive to boiling and a new approach for achieving higher reliability of detection, which were developed at Indira Gandhi Centre for Atomic Research are also presented. 10 refs, 3 figs, 2 tabs

  8. A three-color absorption/scattering imaging technique for simultaneous measurements on distributions of temperature and fuel concentration in a spray

    Science.gov (United States)

    Qi, Wenyuan; Zhang, Yuyin

    2018-04-01

    A three-color imaging technique was proposed for simultaneous measurements on distributions of fuel/air mixture temperature and fuel vapor/liquid concentrations in evaporating sprays. The idea is based on that the vapor concentration is proportional to the absorption of vapor to UV light, the liquid-phase concentration is related to the light extinction due to scattering of droplet to visible light, and the mixture temperature can be correlated to the absorbance ratio at two absorbing wavelengths or narrow bands. For verifying the imaging system, the molar absorption coefficients of p-xylene at the three narrow bands, which were centered respectively at 265, 289, and 532 nm with FWHM of 10 nm, were measured in a specially designed calibration chamber at different temperatures (423-606 K) and pressure of 3.6 bar. It was found that the ratio of the molar absorption coefficients of p-xylene at the two narrow bands centered at the two UV wavelengths is sensitive to the mixture temperature. On the other hand, the distributions of fuel vapor/liquid concentrations can be obtained by use of absorbance due to ultraviolet absorption of vapor and visible light scattering of droplets. Combining these two methods, a simultaneous measurement on distributions of mixture temperature and fuel vapor/liquid concentrations can be realized. In addition, the temperature field obtained from the ratio of the two absorbing narrow bands can be further used to improve the measurement accuracy of vapor/liquid concentrations, because the absorption coefficients depend on temperature. This diagnostic was applied to an evaporating spray inside a high-temperature and high-pressure constant volume chamber.

  9. Triple-Pulse Integrated Path Differential Absorption Lidar for Carbon Dioxide Measurement - Novel Lidar Technologies and Techniques with Path to Space

    Science.gov (United States)

    Singh, Upendra N.; Refaat, Tamer F.; Petros, Mulugeta

    2017-01-01

    The societal benefits of understanding climate change through identification of global carbon dioxide sources and sinks led to the desired NASA's active sensing of carbon dioxide emissions over nights, days, and seasons (ASCENDS) space-based missions of global carbon dioxide measurements. For more than 15 years, NASA Langley Research Center (LaRC) have developed several carbon dioxide active remote sensors using the differential absorption lidar (DIAL) technique operating at the two-micron wavelength. Currently, an airborne two-micron triple-pulse integrated path differential absorption (IPDA) lidar is under development. This IPDA lidar measures carbon dioxide as well as water vapor, the dominant interfering molecule on carbon dioxide remote sensing. Advancement of this triple-pulse IPDA lidar development is presented.

  10. A Review of Financial Accounting Fraud Detection based on Data Mining Techniques

    Science.gov (United States)

    Sharma, Anuj; Kumar Panigrahi, Prabin

    2012-02-01

    With an upsurge in financial accounting fraud in the current economic scenario experienced, financial accounting fraud detection (FAFD) has become an emerging topic of great importance for academic, research and industries. The failure of internal auditing system of the organization in identifying the accounting frauds has lead to use of specialized procedures to detect financial accounting fraud, collective known as forensic accounting. Data mining techniques are providing great aid in financial accounting fraud detection, since dealing with the large data volumes and complexities of financial data are big challenges for forensic accounting. This paper presents a comprehensive review of the literature on the application of data mining techniques for the detection of financial accounting fraud and proposes a framework for data mining techniques based accounting fraud detection. The systematic and comprehensive literature review of the data mining techniques applicable to financial accounting fraud detection may provide a foundation to future research in this field. The findings of this review show that data mining techniques like logistic models, neural networks, Bayesian belief network, and decision trees have been applied most extensively to provide primary solutions to the problems inherent in the detection and classification of fraudulent data.

  11. Detection of silver nanoparticles in parsley by solid sampling high-resolution-continuum source atomic absorption spectrometry.

    Science.gov (United States)

    Feichtmeier, Nadine S; Leopold, Kerstin

    2014-06-01

    In this work, we present a fast and simple approach for detection of silver nanoparticles (AgNPs) in biological material (parsley) by solid sampling high-resolution-continuum source atomic absorption spectrometry (HR-CS AAS). A novel evaluation strategy was developed in order to distinguish AgNPs from ionic silver and for sizing of AgNPs. For this purpose, atomisation delay was introduced as significant indication of AgNPs, whereas atomisation rates allow distinction of 20-, 60-, and 80-nm AgNPs. Atomisation delays were found to be higher for samples containing silver ions than for samples containing silver nanoparticles. A maximum difference in atomisation delay normalised by the sample weight of 6.27 ± 0.96 s mg(-1) was obtained after optimisation of the furnace program of the AAS. For this purpose, a multivariate experimental design was used varying atomisation temperature, atomisation heating rate and pyrolysis temperature. Atomisation rates were calculated as the slope of the first inflection point of the absorbance signals and correlated with the size of the AgNPs in the biological sample. Hence, solid sampling HR-CS AAS was proved to be a promising tool for identifying and distinguishing silver nanoparticles from ionic silver directly in solid biological samples.

  12. A Monte Carlo technique for signal level detection in implanted intracranial pressure monitoring.

    Science.gov (United States)

    Avent, R K; Charlton, J D; Nagle, H T; Johnson, R N

    1987-01-01

    Statistical monitoring techniques like CUSUM, Trigg's tracking signal and EMP filtering have a major advantage over more recent techniques, such as Kalman filtering, because of their inherent simplicity. In many biomedical applications, such as electronic implantable devices, these simpler techniques have greater utility because of the reduced requirements on power, logic complexity and sampling speed. The determination of signal means using some of the earlier techniques are reviewed in this paper, and a new Monte Carlo based method with greater capability to sparsely sample a waveform and obtain an accurate mean value is presented. This technique may find widespread use as a trend detection method when reduced power consumption is a requirement.

  13. Sample preparation for arsenic speciation analysis in baby food by generation of substituted arsines with atomic absorption spectrometry detection.

    Science.gov (United States)

    Huber, Charles S; Vale, Maria Goreti R; Dessuy, Morgana B; Svoboda, Milan; Musil, Stanislav; Dědina, Jiři

    2017-12-01

    A slurry sampling procedure for arsenic speciation analysis in baby food by arsane generation, cryogenic trapping and detection with atomic absorption spectrometry is presented. Several procedures were tested for slurry preparation, including different reagents (HNO 3 , HCl and tetramethylammonium hydroxide - TMAH) and their concentrations, water bath heating and ultrasound-assisted agitation. The best results for inorganic arsenic (iAs) and dimethylarsinate (DMA) were reached when using 3molL -1 HCl under heating and ultrasound-assisted agitation. The developed method was applied for the analysis of five porridge powder and six baby meal samples. The trueness of the method was checked with a certified reference material (CRM) of total arsenic (tAs), iAs and DMA in rice (ERM-BC211). Arsenic recoveries (mass balance) for all samples and CRM were performed by the determination of the tAs by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted digestion and its comparison against the sum of the results from the speciation analysis. The relative limits of detection were 0.44, 0.24 and 0.16µgkg -1 for iAs, methylarsonate and DMA, respectively. The concentrations of the most toxic arsenic species (iAs) in the analyzed baby food samples ranged between 4.2 and 99µgkg -1 which were below the limits of 300, 200 and 100µgkg -1 set by the Brazilian, Chinese and European legislation, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Methods and techniques of detecting petroleum-polluted water. Metody i tekhnika obnaruzheniya neftyanykh zagroyaznenii vod

    Energy Technology Data Exchange (ETDEWEB)

    Bogorodskii, V V; Kropotkin, M A; Sheveleva, T Yu

    1975-01-01

    The booklet presents physical principles and techniques of contact and remote sensing of oil pollution. Different methods and their practical possibilities are discussed. The possibility of application of remote CO/sub 2/-laser radar technique for the detection of oil pollution is considered. The booklet may be useful for specialists in oceanology, oceanic physics, meteorology, and in remote physical methods for environmental studies.

  15. Data-Mining Techniques in Detecting Factors Linked to Academic Achievement

    Science.gov (United States)

    Martínez Abad, Fernando; Chaparro Caso López, Alicia A.

    2017-01-01

    In light of the emergence of statistical analysis techniques based on data mining in education sciences, and the potential they offer to detect non-trivial information in large databases, this paper presents a procedure used to detect factors linked to academic achievement in large-scale assessments. The study is based on a non-experimental,…

  16. Fluorescence hyperspectral imaging technique for the foreign substance detection on fresh-cut lettuce

    Science.gov (United States)

    Nondestructive methods based on fluorescence hyperspectral imaging (HSI) techniques were developed in order to detect worms on fresh-cut lettuce. The optimal wavebands for detecting worms on fresh-cut lettuce were investigated using the one-way ANOVA analysis and correlation analysis. The worm detec...

  17. Contactless conductivity detection for analytical techniques — Developments from 2014 to 2016

    Czech Academy of Sciences Publication Activity Database

    Kubáň, Pavel; Hauser, P.C.

    2017-01-01

    Roč. 38, č. 1 (2017), s. 95-114 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA16-09135S Institutional support: RVO:68081715 Keywords : capacitively coupled contactless conductivity detection * capillary electrophoresis * contactless conductivity detection * analytical techniques * review Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 2.744, year: 2016

  18. A Novel Technique to Detect Code for SAC-OCDMA System

    Science.gov (United States)

    Bharti, Manisha; Kumar, Manoj; Sharma, Ajay K.

    2018-04-01

    The main task of optical code division multiple access (OCDMA) system is the detection of code used by a user in presence of multiple access interference (MAI). In this paper, new method of detection known as XOR subtraction detection for spectral amplitude coding OCDMA (SAC-OCDMA) based on double weight codes has been proposed and presented. As MAI is the main source of performance deterioration in OCDMA system, therefore, SAC technique is used in this paper to eliminate the effect of MAI up to a large extent. A comparative analysis is then made between the proposed scheme and other conventional detection schemes used like complimentary subtraction detection, AND subtraction detection and NAND subtraction detection. The system performance is characterized by Q-factor, BER and received optical power (ROP) with respect to input laser power and fiber length. The theoretical and simulation investigations reveal that the proposed detection technique provides better quality factor, security and received power in comparison to other conventional techniques. The wide opening of eye in case of proposed technique also proves its robustness.

  19. AN IMAGE-ANALYSIS TECHNIQUE FOR DETECTION OF RADIATION-INDUCED DNA FRAGMENTATION AFTER CHEF ELECTROPHORESIS

    NARCIS (Netherlands)

    ROSEMANN, M; KANON, B; KONINGS, AWT; KAMPINGA, HH

    CHEF-electrophoresis was used as a technique to detect radiation-induced DNA breakage with special emphasis to biological relevant X-ray doses (0-10 Gy). Fluorescence detection of DNA-fragments using a sensitive image analysis system was directly compared with conventional scintillation counting of

  20. Optically detected X-ray absorption spectroscopy measurements as a means of monitoring corrosion layers on copper.

    Science.gov (United States)

    Dowsett, Mark G; Adriaens, Annemie; Jones, Gareth K C; Poolton, Nigel; Fiddy, Steven; Nikitenko, Sergé

    2008-11-15

    XANES and EXAFS information is conventionally measured in transmission through the energy-dependent absorption of X-rays or by observing X-ray fluorescence, but secondary fluorescence processes, such as the emission of electrons and optical photons (e.g., 200-1000 nm), can also be used as a carrier of the XAS signatures, providing complementary information such as improved surface specificity. Where the near-visible photons have a shorter range in a material, the data will be more surface specific. Moreover, optical radiation may escape more readily than X-rays through liquid in an environmental cell. Here, we describe a first test of optically detected X-ray absorption spectroscopy (ODXAS) for monitoring electrochemical treatments on copper-based alloys, for example, heritage metals. Artificially made corrosion products deposited on a copper substrate were analyzed in air and in a 1% (w/v) sodium sesquicarbonate solution to simulate typical conservation methods for copper-based objects recovered from marine environments. The measurements were made on stations 7.1 and 9.2 MF (SRS Daresbury, UK) using the mobile luminescence end station (MoLES), supplemented by XAS measurements taken on DUBBLE (BM26 A) at the ESRF. The ODXAS spectra usually contain fine structure similar to that of XAS spectra measured in X-ray fluorescence. Importantly, for the compounds examined, the ODXAS is significantly more surface specific, and >98% characteristic of thin surface layers of 0.5-1.5-microm thickness in cases where X-ray measurements are dominated by the substrate. However, EXAFS and XANES from broadband optical measurements are superimposed on a high background due to other optical emission modes. This produces statistical fluctuations up to double what would be expected from normal counting statistics because the data retain the absolute statistical fluctuation in the original raw count, while losing up to 70% of their magnitude when background is removed. The problem may be

  1. Assessment of metal and trace element concentrations in the Cananeia estuary, Brazil, by neutron activation and atomic absorption techniques

    International Nuclear Information System (INIS)

    Amorim, E.P.; Favaro, D.I.T.; Berbel, G.B.B.; Braga, E.S.

    2008-01-01

    Twenty six bottom sediment samples were collected from the Cananeia estuary in summer and winter of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis. Total mercury was determined by cold vapor atomic absorption. As, Cr, Hg and Zn concentrations were compared to the Canadian oriented values (TEL and PEL). Sample points 4 and 9 presented higher concentration for most elements and As and Cr exceeded the TEL values. Organic matter (>10%) associated with siltic and clay sediments was observed. Climatic conditions, hydrodynamic and biogeochemical processes promote differences in seasonal concentrations of elements at some points, which contribute to special distributions. (author)

  2. Indirect ultraviolet detection of alkaline earth metal ions using an imidazolium ionic liquid as an ultraviolet absorption reagent in ion chromatography.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2017-04-01

    A convenient and versatile method was developed for the separation and detection of alkaline earth metal ions by ion chromatography with indirect UV detection. The chromatographic separation of Mg 2+ , Ca 2+ , and Sr 2+ was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid as the mobile phase, in which the imidazolium ionic liquid acted as an UV-absorption reagent. The effects of imidazolium ionic liquids, detection wavelength, acids in the mobile phase, and column temperature on the retention of Mg 2+ , Ca 2+ , and Sr 2+ were investigated. The main factors influencing the separation and detection were the background UV absorption reagent and the concentration of hydrogen ion in ion chromatography with indirect UV detection. The successful separation and detection of Mg 2+ , Ca 2+ , and Sr 2+ within 14 min were achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.06, 0.12, and 0.23 mg/L, respectively. A new separation and detection method of alkaline earth metal ions by ion chromatography with indirect UV detection was developed, and the application range of ionic liquids was expanded. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A Comprehensive Review and meta-analysis on Applications of Machine Learning Techniques in Intrusion Detection

    Directory of Open Access Journals (Sweden)

    Manojit Chattopadhyay

    2018-05-01

    Full Text Available Securing a machine from various cyber-attacks has been of serious concern for researchers, statutory bodies such as governments, business organizations and users in both wired and wireless media. However, during the last decade, the amount of data handling by any device, particularly servers, has increased exponentially and hence the security of these devices has become a matter of utmost concern. This paper attempts to examine the challenges in the application of machine learning techniques to intrusion detection. We review different inherent issues in defining and applying the machine learning techniques to intrusion detection. We also attempt to identify the best technological solution for changing usage pattern by comparing different machine learning techniques on different datasets and summarizing their performance using various performance metrics. This paper highlights the research challenges and future trends of intrusion detection in dynamic scenarios of intrusion detection problems in diverse network technologies.

  4. Study on rice absorption and distribution of Cd in applying Zn fertilizer with 65Zn, 115Cdm tracing technique

    International Nuclear Information System (INIS)

    Tang Nianxin; Shen Jinxiong

    1994-01-01

    Results of study by using 65 Zn and 115 Cd m tracers show that, along with the increase of the amount of Cd in applying Zn fertilizer to soil, rice has the phenomena of growth retard and tiller delay in the earlier growing stage. The inhibiting phenomenon is lightened along with the progress of rice growth. Very small quantity of Cd might be helpful to the growth of rice. It would cause serious inhibition to rice growth when the amount of Cd reaches to a definite limitation (64 x 10 -6 ). The distribution of Cd in a rice plant follows the following order in content: root>stem and leaves>brown rice>ear stalk>rice shell. Cd is mainly accumulated in rice root, taking 90% of the total amount of Cd contained in whole rice plant. The amount of Cd absorbed by rice increases with the amount of Cd applied to soil, though the total absorption extremely low, for example, only about 0.1% of the applied amount could be absorbed by two crops of rice, most of the applied Cd still retains in soil. Less and less Zn could be absorbed and utilized by rice along with the increase of the amount of the applied Cd. Application of Mn fertilizer affects negatively the absorption of Cd by rice, especially in brown rice

  5. Structural study on Ni nanowires in an anodic alumina membrane by using in situ heating extended x-ray absorption fine structure and x-ray diffraction techniques

    International Nuclear Information System (INIS)

    Cai Quan; Chen Xing; Chen Zhongjun; Wang Wei; Mo Guang; Wu Zhonghua; Zhang Junxi; Zhang Lide; Pan Wei

    2008-01-01

    Polycrystalline Ni nanowires have been prepared by electrochemical deposition in an anodic alumina membrane template with a nanopore size of about 60 nm. In situ heating extended x-ray absorption fine structure and x-ray diffraction techniques are used to probe the atomic structures. The nanowires are identified as being mixtures of nanocrystallites and amorphous phase. The nanocrystallites have the same thermal expansion coefficient, of 1.7 x 10 -5 K -1 , as Ni bulk; however, the amorphous phase has a much larger thermal expansion coefficient of 3.5 x 10 -5 K -1 . Details of the Ni nanowire structures are discussed in this paper

  6. Study of some Ayurvedic Indian medicinal plants for the essential trace elemental contents by instrumental neutron activation analysis and atomic absorption spectroscopy techniques

    International Nuclear Information System (INIS)

    Lokhande, R.S.; Singare, P.U.; Andhele, M.L.; Acharya, R.; Nair, A.G.C.; Reddy, A.V.R.

    2009-01-01

    Elemental analysis of some medicinal plants used in the Indian Ayurvedic system was performed by employing instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) techniques. The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted by gamma ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector. Most of the medicinal plants were found to be rich in one or more of the elements under study. The variation in elemental concentration in same medicinal plants samples collected in summer, winter and rainy seasons was studied and the biological effects of these elements on human beings are discussed. (orig.)

  7. Measurement of polarization dependence of two-photon absorption coefficient in InP using extended Z-scan technique for thick materials

    Science.gov (United States)

    Oishi, Masaki; Shinozaki, Tomohisa; Hara, Hikaru; Yamamoto, Kazunuki; Matsusue, Toshio; Bando, Hiroyuki

    2018-03-01

    The two-photon absorption coefficient β in InP has been measured in the wavelength range of 1640 to 1800 nm by the Z-scan technique in relatively thick materials. The values of β have been evaluated from the fit to the equation including the spatial and temporal profiles of the focused Gaussian beam. The polarization dependence of β has also been measured. The dependence has been expressed very well by the expression of β with the imaginary part of the third-order nonlinear susceptibility tensor χ(3).

  8. Experimental Study on Corrosion Detection of Aluminum Alloy Using Lamb Wave Mixing Technique

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Heeung; Lee, Jaesun; Cho, Younho [Pusan Nat’l Univ., Busan (Korea, Republic of)

    2016-11-15

    In this study, the Lamb wave mixing technique, which is basised on advanced research on the nonlinear bulk wave mixing technique, is applied for corrosion detection. To demonstrate the validity of the Lamb wave mixing technique, an experiment was performed with normal and corroded specimens. Comparison group in an experimentation are selected to mode and frequency with dominant in-plane displacement and out-of-plane displacement of Lamb waves. The results showed that the Lamb wave mixing technique can monitor corrosion defects, and it has a trend similar to that of the conventional Lamb wave technique. It was confirmed that the dominant displacement and mode matching the theory were generated. Flaw detectability is determined depending on displacement ratio instead of using the measurement method and mode selection.

  9. Enhancement of crack detection in stud bolts of nuclear reactor by ultrasonic technique

    International Nuclear Information System (INIS)

    Lee, Joon-Hyun; Choi, Sang-Woo; Oh, Won-Deok

    2004-01-01

    The stud bolt is one of crucial parts for safety of reactor vessels in nuclear power plants. Crack initiation and propagation were reported in stud bolts using closure of reactor vessel and head. Stud bolts are inspected by ultrasonic technique during overhaul periodically for the prevention of stud bolt failure and radioactive leakage from nuclear reactor. In conventional ultrasonic testing for inspection of stud bolts, crack was detected by using shadow effect. It takes too much time to inspect stud bolt by using conventional ultrasonic technique. In addition, there were numerous spurious signals reflected from every oblique surfaces of thread. In this study, the signal processing technique for enhancing conventional ultrasonic technique and the advanced ultrasonic phased array technique were introduced for inspect stud bolts. The signal processing technique provides removing spurious signal reflected from every oblique surfaces of thread and enhances detectability of defects. The phased array technique provides fast inspection and can be applied for structure of complex shape. There are sector scanning and linear scanning methods in phased array technique, and these scanning methods were applied to inspect stud bolt and detectability was investigated. (author)

  10. A structural study of bone changes in knee osteoarthritis by synchrotron-based X-ray fluorescence and X-ray absorption spectroscopy techniques

    Science.gov (United States)

    Sindhupakorn, Bura; Thienpratharn, Suwittaya; Kidkhunthod, Pinit

    2017-10-01

    Osteoarthritis (OA) is characterized by degeneration of articular cartilage and thickening of subchondral bone. The present study investigated the changing of biochemical components of cartilage and bone compared between normal and OA people. Using Synchrotron-based X-ray fluorescence (SR-XRF) and X-ray absorption spectroscopy (XAS) techniquesincluding X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) were employed for the bone changes in kneeosteoarthritisstudies. The bone samples were collected from various osteoarthritis patients with both male and female in the ages range between 20 and 74 years old. SR-XRF results excited at 4240 eV for Ca elements show a majority three main groups, based on their XRF intensities, 20-36 years, 40-60 years and over 70 years, respectively. By employing XAS techniques, XANES features can be used to clearly explain in term of electronic transitions occurring in bone samples which are affected from osteoarthritis symptoms. Moreover, a structural change around Ca ions in bone samples is obviously obtained by EXAFS results indicating an increase of Ca-amorphous phase when the ages increase.

  11. Leak detection and localization in a pipeline system by application of statistical analysis techniques

    International Nuclear Information System (INIS)

    Fukuda, Toshio; Mitsuoka, Toyokazu.

    1985-01-01

    The detection of leak in piping system is an important diagnostic technique for facilities to prevent accidents and to take maintenance measures, since the occurrence of leak lowers productivity and causes environmental destruction. As the first step, it is necessary to detect the occurrence of leak without delay, and as the second step, if the place of leak occurrence in piping system can be presumed, accident countermeasures become easy. The detection of leak by pressure is usually used for detecting large leak. But the method depending on pressure is simple and advantageous, therefore the extension of the detecting technique by pressure gradient method to the detection of smaller scale leak using statistical analysis techniques was examined for a pipeline in steady operation in this study. Since the flow in a pipe irregularly varies during pumping, statistical means is required for the detection of small leak by pressure. The index for detecting leak proposed in this paper is the difference of the pressure gradient at the both ends of a pipeline. The experimental results on water and air in nylon tubes are reported. (Kako, I.)

  12. Automatic Detection of Optic Disc in Retinal Image by Using Keypoint Detection, Texture Analysis, and Visual Dictionary Techniques

    Directory of Open Access Journals (Sweden)

    Kemal Akyol

    2016-01-01

    Full Text Available With the advances in the computer field, methods and techniques in automatic image processing and analysis provide the opportunity to detect automatically the change and degeneration in retinal images. Localization of the optic disc is extremely important for determining the hard exudate lesions or neovascularization, which is the later phase of diabetic retinopathy, in computer aided eye disease diagnosis systems. Whereas optic disc detection is fairly an easy process in normal retinal images, detecting this region in the retinal image which is diabetic retinopathy disease may be difficult. Sometimes information related to optic disc and hard exudate information may be the same in terms of machine learning. We presented a novel approach for efficient and accurate localization of optic disc in retinal images having noise and other lesions. This approach is comprised of five main steps which are image processing, keypoint extraction, texture analysis, visual dictionary, and classifier techniques. We tested our proposed technique on 3 public datasets and obtained quantitative results. Experimental results show that an average optic disc detection accuracy of 94.38%, 95.00%, and 90.00% is achieved, respectively, on the following public datasets: DIARETDB1, DRIVE, and ROC.

  13. SERS active Ag encapsulated Fe@SiO2 nanorods in electromagnetic wave absorption and crystal violet detection.

    Science.gov (United States)

    Senapati, Samarpita; Srivastava, Suneel Kumar; Singh, Shiv Brat; Kulkarni, Ajit R

    2014-11-01

    The present work is focused on the preparation of Fe nanorods by the chemical reduction of FeCl3 (aq) using NaBH4 in the presence of glycerol as template followed by annealing of the product at 500°C in the presence of H2 gas flow. Subsequently, its surface has been modified by silica followed by silver nanoparticles to form silica coated Fe (Fe@SiO2) and Ag encapsulated Fe@SiO2 nanostructure employing the Stöber method and silver mirror reaction respectively. XRD pattern of the products confirmed the formation of bcc phase of iron and fcc phase of silver, though silica remained amorphous. FESEM images established the growth of iron nanorods from the annealed product and also formation of silica and silver coating on its surface. The appearance of the characteristics bands in FTIR confirmed the presence of SiO2 on the Fe surface. Magnetic measurements at room temperature indicated the ferromagnetic behavior of as prepared iron nanorods, Fe@SiO2 and silver encapsulated Fe@SiO2 nanostructures. All the samples exhibited strong microwave absorption property in the high frequency range (10GHz), though it is superior for Ag encapsulated Fe@SiO2 (-14.7dB) compared with Fe@SiO2 (-9.7dB) nanostructures of the same thickness. The synthesized Ag encapsulated Fe@SiO2 nanostructure also exhibited the SERS phenomena, which is useful in the detection of the carcinogenic dye crystal violet (CV) upto the concentration of 10(-10)M. All these findings clearly demonstrate that the Ag encapsulated Fe@SiO2 nanostructure could efficiently be used in the environmental remediation. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Recursive estimation techniques for detection of small objects in infrared image data

    Science.gov (United States)

    Zeidler, J. R.; Soni, T.; Ku, W. H.

    1992-04-01

    This paper describes a recursive detection scheme for point targets in infrared (IR) images. Estimation of the background noise is done using a weighted autocorrelation matrix update method and the detection statistic is calculated using a recursive technique. A weighting factor allows the algorithm to have finite memory and deal with nonstationary noise characteristics. The detection statistic is created by using a matched filter for colored noise, using the estimated noise autocorrelation matrix. The relationship between the weighting factor, the nonstationarity of the noise and the probability of detection is described. Some results on one- and two-dimensional infrared images are presented.

  15. Measurement of K-shell absorption jump factors and jump ratios in some lanthanide elements using EDXRF technique

    International Nuclear Information System (INIS)

    Polat, Recep; İçelli, Orhan; Yalçın, Zeynel; Pesen, Erhan; Orak, Salim

    2013-01-01

    Highlights: ► Mass attenuation coefficients, jump factor and jump ratio for lanthanide elements are obtained. ► The method used in this experiment is combined both transmission and scattering geometry. ► Secondary gamma rays energy is 59.5 keV. ► Experimental values of jump factor and jump ratio for K shell are new. ► The experimental values are in good agreement with those calculated theoretically. - Abstract: 59.5 keV gamma rays scattered by an aluminum foil have been used as a radiation source to measure the absorption jump factor and jump ratios for absorbers Ce, Pr, Nd, Sm, Eu and Tb. The theoretical and experimental values are compared with the corresponding ones in the literature

  16. Assessment of elemental pollution in soil of Islamabad city using instrumental neutron activation analysis and atomic absorption spectrometry techniques

    International Nuclear Information System (INIS)

    Daud, M.; Wasim, M.; Khalid, N.; Zaidi, J.H.; Iqbal, J.

    2009-01-01

    The soil samples of nine different sites in Islamabad were studied for their elemental composition. Instrumental neutron activation analysis and atomic absorption spectrometry were employed and 33 elements were determined. The acquired data were analyzed using descriptive statistics, principal component analysis, cluster analysis, pollution level index and enrichment factor. A perusal of results shows a distribution of elemental concentration in two major groups, one along the highway and the other in industrial area of Islamabad. The soil along the highway sites was found to be relatively less polluted than at the sites in the industrial area. The enrichment factor indicates the presence of As, Pb, Sb, Se and Sn at higher levels. The method validation was done by analyzing IAEA reference materials SL-1 (lake sediment) and S7 (soil). (orig.)

  17. Cationic effect on dye-sensitized solar cell properties using electrochemical impedance and transient absorption spectroscopy techniques

    International Nuclear Information System (INIS)

    Gupta, Ravindra Kumar; Bedja, Idriss

    2017-01-01

    Redox-couple polymer electrolytes, (poly(ethylene oxide)-succinonitrile) blend/MI-I 2 , where M  =  Li or K, were prepared by the solution cast method. Owing to the plasticizing property of K + ions, the K + ion-based electrolyte exhibited better electrical conductivity than the Li + ion-based electrolyte, which did however exhibit better photovoltaic properties. Electrochemical impedance spectroscopy revealed faster redox species diffusions and interfacial processes in the Li + ion-based dye-sensitized solar cells than in the K + ion-based ones. Transient absorption spectroscopy ascertained faster dye-regeneration by the Li + ion-based electrolyte than the K + ion-based electrolyte. (paper)

  18. A COMPARISON OF SPECTROSCOPIC VERSUS IMAGING TECHNIQUES FOR DETECTING CLOSE COMPANIONS TO KEPLER OBJECTS OF INTEREST

    International Nuclear Information System (INIS)

    Teske, Johanna K.; Everett, Mark E.; Hirsch, Lea; Furlan, Elise; Ciardi, David R.; Horch, Elliott P.; Howell, Steve B.; Gonzales, Erica; Crepp, Justin R.

    2015-01-01

    Kepler planet candidates require both spectroscopic and imaging follow-up observations to rule out false positives and detect blended stars. Traditionally, spectroscopy and high-resolution imaging have probed different host star companion parameter spaces, the former detecting tight binaries and the latter detecting wider bound companions as well as chance background stars. In this paper, we examine a sample of 11 Kepler host stars with companions detected by two techniques—near-infrared adaptive optics and/or optical speckle interferometry imaging, and a new spectroscopic deblending method. We compare the companion effective temperatures (T eff ) and flux ratios (F B /F A , where A is the primary and B is the companion) derived from each technique and find no cases where both companion parameters agree within 1σ errors. In 3/11 cases the companion T eff values agree within 1σ errors, and in 2/11 cases the companion F B /F A values agree within 1σ errors. Examining each Kepler system individually considering multiple avenues (isochrone mapping, contrast curves, probability of being bound), we suggest two cases for which the techniques most likely agree in their companion detections (detect the same companion star). Overall, our results support the advantage that the spectroscopic deblending technique has for finding very close-in companions (θ ≲ 0.″02–0.″05) that are not easily detectable with imaging. However, we also specifically show how high-contrast AO and speckle imaging observations detect companions at larger separations (θ ≥ 0.″02–0.″05) that are missed by the spectroscopic technique, provide additional information for characterizing the companion and its potential contamination (e.g., position angle, separation, magnitude differences), and cover a wider range of primary star effective temperatures. The investigation presented here illustrates the utility of combining the two techniques to reveal higher-order multiples in known

  19. Improving Intrusion Detection System Based on Snort Rules for Network Probe Attacks Detection with Association Rules Technique of Data Mining

    Directory of Open Access Journals (Sweden)

    Nattawat Khamphakdee

    2015-07-01

    Full Text Available The intrusion detection system (IDS is an important network security tool for securing computer and network systems. It is able to detect and monitor network traffic data. Snort IDS is an open-source network security tool. It can search and match rules with network traffic data in order to detect attacks, and generate an alert. However, the Snort IDS  can detect only known attacks. Therefore, we have proposed a procedure for improving Snort IDS rules, based on the association rules data mining technique for detection of network probe attacks.  We employed the MIT-DARPA 1999 data set for the experimental evaluation. Since behavior pattern traffic data are both normal and abnormal, the abnormal behavior data is detected by way of the Snort IDS. The experimental results showed that the proposed Snort IDS rules, based on data mining detection of network probe attacks, proved more efficient than the original Snort IDS rules, as well as icmp.rules and icmp-info.rules of Snort IDS.  The suitable parameters for the proposed Snort IDS rules are defined as follows: Min_sup set to 10%, and Min_conf set to 100%, and through the application of eight variable attributes. As more suitable parameters are applied, higher accuracy is achieved.

  20. Vitamin B 12 absorption: correction of intestinal retention by whole-body profile activity of vitamin B 12-58 cobalt and by double tracer technique

    International Nuclear Information System (INIS)

    Goncalves, M.R. Bencke; Gheldof, R.; Paternot, L. van Tricht; Delmotte, E.; Verschaeren, A.; Martin, P.; Verhas, M.; Universidade Federal, Rio de Janeiro, RJ

    1997-01-01

    Full text. Intestinal retention could give false negative results in determining the whole-body retention of vitamin B 12 absorption (WBC B12-58Co). After having validate the WBC B12-58Co, taking the Schilling test as reference, we have studied the feasibility to evaluate the intestinal contamination by measurement of the profile activity distribution of vitamin B12-58Co and by a double tracer technique (WBC B12-58Co/ WBC 51 Cr Cl3). Methodology: twenty five patients were studied for the setting up of the new methodology. For eleven of them the WBC B12-58 Co retention was measured at the 7th day after the oral administration of 37KBq of B12-58Co using a four detectors whole body counter. One week later, a Schilling test was performed after the oral absorption of 18,5 KBq B12-57Co. Results were expressed as %ID. In these patients, one single peak of hepatic activity was observed on the whole body profile and thus no further intestinal correction was needed. In order to evaluate the intestinal contribution, we made in nine other patients the profile of the whole body distribution of activity at 1 h, 1 week and two weeks after the oral administration of B12-58Co. For five other patients a double tracer technique was used for intestinal correction after the simultaneous oral administration of 37 KBq of B12-58Co and 1,85 MBq of 51 Cr Cl3. The B12-58Co absorption was evaluated after intestinal correction based on subtraction of the 51Cr Cl3 contribution after the formula: B12-58Co(%ID) = WBC B12-58Co - WBC 51 Cr Cl3/1 - WBC 51 Cr Cl3. Results: the correlation with the Schilling test was found excellent: r=0,94 (n=11). The normality for WBC retention (n=7) was define as 53,2 +-12,4% ID (SD). For nine patients studied at the 7th day, the presence of a double peak (hepatic and intestinal peaks) allowed the subtraction by exponential extrapolation; the correction range was 4,4% to 37,2%. With the exception of one observation there was no difference in the measure of vitamin

  1. Investigation of the effect of solubility increase at the main absorption site on bioavailability of BCS class II drug (risperidone) using liquisolid technique.

    Science.gov (United States)

    Khames, Ahmed

    2017-11-01

    BCS class II drugs usually suffer inadequate bioavailability as dissolution step is the absorption rate limiting step. In this work, the effect of solubility increase at the main absorption site for these drugs was investigated using risperidone as a drug model. Liquisolid technique was applied to prepare risperidone per-oral tablets of high dissolution rate at intestinal pH (6.8) using versatile nonionic surfactants of high solubilizing ability [Transcutol HP, Labrasol and Labrasol/Labrafil (1:1) mixture] as liquid vehicles at different drug concentrations (10-30%) and fixed (R). The prepared liquisolid tablets were fully evaluated and the dissolution rate at pH 6.8 was investigated. The formulae that showed significantly different release rate were selected and subjected to mathematical modeling using DE 25 , MDT and similarity factor (f2). Depending on mathematical modeling results, formula of higher dissolution rate was subjected to solid state characterization using differential scanning calorimetric (DSC), infrared spectroscopy (IR) and X-ray diffraction (XRD). Finally, the drug bioavailability was studied in comparison to conventional tablets in rabbits. Results showed that liquisolid tablet prepared using Labrasol/Labrafil (1:1) mixture as liquid vehicle containing 10% risperidone is a compatible formula with law drug crystallinity and higher dissolution rate (100% in 25 min). The drug bioavailability was significantly increased in comparison to the conventional tablets (1441.711 μg h/mL and 137.518 μg/mL in comparison to 321.011 μg h/mL and 38.673 μg/mL for AUC and Cp max , respectively). This led to the conclusion that liquisolid technique was efficiently improved drug solubility and solubility increase of BCS class II drugs at their main absorption site significantly increases their bioavailability.

  2. Combining X-ray Absorption and X-ray Diffraction Techniques for in Situ Studies of Chemical Transformations in Heterogeneous Catalysis: Advantages and Limitations

    International Nuclear Information System (INIS)

    Frenkel, A.I.; Hanson, J.; Wang, Q.; Marinkovic, N.; Chen, J.G.; Barrio, L.; Si, R.; Lopez Camara, A.; Estrella, A.M.; Rodriguez, J.A.

    2011-01-01

    Recent advances in catalysis instrumentations include synchrotron-based facilities where time-resolved X-ray scattering and absorption techniques are combined in the same in situ or operando experiment to study catalysts at work. To evaluate the advances and limitations of this method, we performed a series of experiments at the new XAFS/XRD instrument in the National Synchrotron Light Source. Nearly simultaneous X-ray diffraction (XRD) and X-ray absorption fine-structure (XAFS) measurements of structure and kinetics of several catalysts under reducing or oxidizing conditions have been performed and carefully analyzed. For CuFe 2 O 4 under reducing conditions, the combined use of the two techniques allowed us to obtain accurate data on kinetics of nucleation and growth of metallic Cu. For the inverse catalyst CuO/CeO 2 that underwent isothermal reduction (with CO) and oxidation (with O 2 ), the XAFS data measured in the same experiment with XRD revealed strongly disordered Cu species that went undetected by diffraction. These and other examples emphasize the unique sensitivity of these two complementary methods to follow catalytic processes in the broad ranges of length and time scales.

  3. Enhancement of crack detection in stud bolts of nuclear reactor by ultrasonic signal processing technique

    International Nuclear Information System (INIS)

    Lee, J.H.; Oh, W.D.; Choi, S.W.; Park, M.H.

    2004-01-01

    'Full-text:' The stud bolts is one of the most critical parts for safety of reactor vessels in the nuclear power plants. However, in the application of ultrasonic technique for crack detection in stud bolt, some difficulties encountered are classification of crack signal from the signals reflected from threads part in stud bolt. In this study, shadow effect technique combined with new signal processing method is Investigated to enhance the detectability of small crack initiated from root of thread in stud bolt. The key idea of signal processing is based on the fact that the shape of waveforms from the threads is uniform since the shape of the threads in a bolt is same. If some cracks exist in the thread, the flaw signals are different to the reference signals. It is demonstrated that the small flaws are efficiently detected by novel ultrasonic technique combined with this new signal processing concept. (author)

  4. Artificial neural network techniques to improve the ability of optical coherence tomography to detect optic neuritis.

    Science.gov (United States)

    Garcia-Martin, Elena; Herrero, Raquel; Bambo, Maria P; Ara, Jose R; Martin, Jesus; Polo, Vicente; Larrosa, Jose M; Garcia-Feijoo, Julian; Pablo, Luis E

    2015-01-01

    To analyze the ability of Spectralis optical coherence tomography (OCT) to detect multiple sclerosis (MS) and to distinguish MS eyes with antecedent optic neuritis (ON). To analyze the capability of artificial neural network (ANN) techniques to improve the diagnostic precision. MS patients and controls were enrolled (n = 217). OCT was used to determine the 768 retinal nerve fiber layer thicknesses. Sensitivity and specificity were evaluated to test the ability of OCT to discriminate between MS and healthy eyes, and between MS with and without antecedent ON using ANN. Using ANN technique multilayer perceptrons, OCT could detect MS with a sensitivity of 89.3%, a specificity of 87.6%, and a diagnostic precision of 88.5%. Compared with the OCT-provided parameters, the ANN had a better sensitivity-specificity balance. ANN technique improves the capability of Spectralis OCT to detect MS disease and to distinguish MS eyes with or without antecedent ON.

  5. A leakage-free resonance sparse decomposition technique for bearing fault detection in gearboxes

    Science.gov (United States)

    Osman, Shazali; Wang, Wilson

    2018-03-01

    Most of rotating machinery deficiencies are related to defects in rolling element bearings. Reliable bearing fault detection still remains a challenging task, especially for bearings in gearboxes as bearing-defect-related features are nonstationary and modulated by gear mesh vibration. A new leakage-free resonance sparse decomposition (LRSD) technique is proposed in this paper for early bearing fault detection of gearboxes. In the proposed LRSD technique, a leakage-free filter is suggested to remove strong gear mesh and shaft running signatures. A kurtosis and cosine distance measure is suggested to select appropriate redundancy r and quality factor Q. The signal residual is processed by signal sparse decomposition for highpass and lowpass resonance analysis to extract representative features for bearing fault detection. The effectiveness of the proposed technique is verified by a succession of experimental tests corresponding to different gearbox and bearing conditions.

  6. Investigating the probability of detection of typical cavity shapes through modelling and comparison of geophysical techniques

    Science.gov (United States)

    James, P.

    2011-12-01

    With a growing need for housing in the U.K., the government has proposed increased development of brownfield sites. However, old mine workings and natural cavities represent a potential hazard before, during and after construction on such sites, and add further complication to subsurface parameters. Cavities are hence a limitation to certain redevelopment and their detection is an ever important consideration. The current standard technique for cavity detection is a borehole grid, which is intrusive, non-continuous, slow and expensive. A new robust investigation standard in the detection of cavities is sought and geophysical techniques offer an attractive alternative. Geophysical techniques have previously been utilised successfully in the detection of cavities in various geologies, but still has an uncertain reputation in the engineering industry. Engineers are unsure of the techniques and are inclined to rely on well known techniques than utilise new technologies. Bad experiences with geophysics are commonly due to the indiscriminate choice of particular techniques. It is imperative that a geophysical survey is designed with the specific site and target in mind at all times, and the ability and judgement to rule out some, or all, techniques. To this author's knowledge no comparative software exists to aid technique choice. Also, previous modelling software limit the shapes of bodies and hence typical cavity shapes are not represented. Here, we introduce 3D modelling software (Matlab) which computes and compares the response to various cavity targets from a range of techniques (gravity, gravity gradient, magnetic, magnetic gradient and GPR). Typical near surface cavity shapes are modelled including shafts, bellpits, various lining and capping materials, and migrating voids. The probability of cavity detection is assessed in typical subsurface and noise conditions across a range of survey parameters. Techniques can be compared and the limits of detection distance

  7. Leak detection of complex pipelines based on the filter diagonalization method: robust technique for eigenvalue assessment

    International Nuclear Information System (INIS)

    Lay-Ekuakille, Aimé; Pariset, Carlo; Trotta, Amerigo

    2010-01-01

    The FDM (filter diagonalization method), an interesting technique used in nuclear magnetic resonance data processing for tackling FFT (fast Fourier transform) limitations, can be used by considering pipelines, especially complex configurations, as a vascular apparatus with arteries, veins, capillaries, etc. Thrombosis, which might occur in humans, can be considered as a leakage for the complex pipeline, the human vascular apparatus. The choice of eigenvalues in FDM or in spectra-based techniques is a key issue in recovering the solution of the main equation (for FDM) or frequency domain transformation (for FFT) in order to determine the accuracy in detecting leaks in pipelines. This paper deals with the possibility of improving the leak detection accuracy of the FDM technique thanks to a robust algorithm by assessing the problem of eigenvalues, making it less experimental and more analytical using Tikhonov-based regularization techniques. The paper starts from the results of previous experimental procedures carried out by the authors

  8. NEUROIMAGING AND PATTERN RECOGNITION TECHNIQUES FOR AUTOMATIC DETECTION OF ALZHEIMER’S DISEASE: A REVIEW

    Directory of Open Access Journals (Sweden)

    Rupali Kamathe

    2017-08-01

    Full Text Available Alzheimer’s disease (AD is the most common form of dementia with currently unavailable firm treatments that can stop or reverse the disease progression. A combination of brain imaging and clinical tests for checking the signs of memory impairment is used to identify patients with AD. In recent years, Neuroimaging techniques combined with machine learning algorithms have received lot of attention in this field. There is a need for development of automated techniques to detect the disease well before patient suffers from irreversible loss. This paper is about the review of such semi or fully automatic techniques with detail comparison of methods implemented, class labels considered, data base used and the results obtained for related study. This review provides detailed comparison of different Neuroimaging techniques and reveals potential application of machine learning algorithms in medical image analysis; particularly in AD enabling even the early detection of the disease- the class labelled as Multiple Cognitive Impairment.

  9. Novel Damage Detection Techniques for Structural Health Monitoring Using a Hybrid Sensor

    Directory of Open Access Journals (Sweden)

    Dengjiang Wang

    2016-01-01

    Full Text Available This study presents a technique for detecting fatigue cracks based on a hybrid sensor monitoring system consisting of a combination of intelligent coating monitoring (ICM and piezoelectric transducer (PZT sensors. An experimental procedure using this hybrid sensor system was designed to monitor the cracks generated by fatigue testing in plate structures. A probability of detection (POD model that quantifies the reliability of damage detection for a specific sensor or the nondestructive testing (NDT method was used to evaluate the weight factor for the ICM and PZT sensors. To estimate the uncertainty of model parameters in this study, the Bayesian method was employed. Realistic data from fatigue testing was used to validate the overall method, and the results show that the novel damage detection technique using a hybrid sensor can quantify fatigue cracks more accurately than results obtained by conventional sensor methods.

  10. Railway Crossing Risk Area Detection Using Linear Regression and Terrain Drop Compensation Techniques

    Science.gov (United States)

    Chen, Wen-Yuan; Wang, Mei; Fu, Zhou-Xing

    2014-01-01

    Most railway accidents happen at railway crossings. Therefore, how to detect humans or objects present in the risk area of a railway crossing and thus prevent accidents are important tasks. In this paper, three strategies are used to detect the risk area of a railway crossing: (1) we use a terrain drop compensation (TDC) technique to solve the problem of the concavity of railway crossings; (2) we use a linear regression technique to predict the position and length of an object from image processing; (3) we have developed a novel strategy called calculating local maximum Y-coordinate object points (CLMYOP) to obtain the ground points of the object. In addition, image preprocessing is also applied to filter out the noise and successfully improve the object detection. From the experimental results, it is demonstrated that our scheme is an effective and corrective method for the detection of railway crossing risk areas. PMID:24936948

  11. Railway Crossing Risk Area Detection Using Linear Regression and Terrain Drop Compensation Techniques

    Directory of Open Access Journals (Sweden)

    Wen-Yuan Chen

    2014-06-01

    Full Text Available Most railway accidents happen at railway crossings. Therefore, how to detect humans or objects present in the risk area of a railway crossing and thus prevent accidents are important tasks. In this paper, three strategies are used to detect the risk area of a railway crossing: (1 we use a terrain drop compensation (TDC technique to solve the problem of the concavity of railway crossings; (2 we use a linear regression technique to predict the position and length of an object from image processing; (3 we have developed a novel strategy called calculating local maximum Y-coordinate object points (CLMYOP to obtain the ground points of the object. In addition, image preprocessing is also applied to filter out the noise and successfully improve the object detection. From the experimental results, it is demonstrated that our scheme is an effective and corrective method for the detection of railway crossing risk areas.

  12. The Application of Helicopter Rotor Defect Detection Using Wavelet Analysis and Neural Network Technique

    Directory of Open Access Journals (Sweden)

    Jin-Li Sun

    2014-06-01

    Full Text Available When detect the helicopter rotor beam with ultrasonic testing, it is difficult to realize the noise removing and quantitative testing. This paper used the wavelet analysis technique to remove the noise among the ultrasonic detection signal and highlight the signal feature of defect, then drew the curve of defect size and signal amplitude. Based on the relationship of defect size and signal amplitude, a BP neural network was built up and the corresponding estimated value of the simulate defect was obtained by repeating training. It was confirmed that the wavelet analysis and neural network technique met the requirements of practical testing.

  13. The background influence of cadmium detection in saline water using PGNAA technique

    International Nuclear Information System (INIS)

    Daqian Hei; Zhou Jiang; Hongtao Wang; Jiatong Li

    2016-01-01

    In order to solve the background influence of cadmium detection in saline water using prompt gamma neutron activation analysis (PGNAA) technique, a series experiments have been designed and carried out. Furthermore, a method based on internal standard was used to correct the neutron self-shielding effect, and the background influence has been decreased sequentially. The results showed a good linear relationship between the characteristic peak counts and the concentrations of cadmium after the neutron self-shielding correction. And in the detection of saline water by PGNAA technique, the proposed methodology can be used to reduce the influence of background with the self-shielding effect correction. (author)

  14. A Determination of the 2200 m/s Absorption Cross Section and Resonance Integral of Arsenic by Pile Oscillator Technique

    Energy Technology Data Exchange (ETDEWEB)

    Sokolowski, E K; Bladh, R

    1969-02-15

    Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier.

  15. A Determination of the 2200 m/s Absorption Cross Section and Resonance Integral of Arsenic by Pile Oscillator Technique

    International Nuclear Information System (INIS)

    Sokolowski, E.K.; Bladh, R.

    1969-02-01

    Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier

  16. Experimental techniques for the detection of the high energy gamma rays of cosmic origin

    International Nuclear Information System (INIS)

    Dumitrescu, Gh.; Angelescu, T.; Radu, A.A.

    2002-01-01

    The observation of high energy gamma rays of cosmic origin in the early 90 by Volcano Ranch experiment opened a new direction of study in astrophysics. The very high energy and the very low flux of these gamma rays, posed numerous detection problems which in turn were the object of a very intense research activity. The present article tries to review the detection techniques for the high energy gamma rays of cosmic origin. In the 'Introduction' we summarize the specific problems involved in the detection of this type of radiation. 'Chapter 1' presents the classic technique based on the use of scintillation detectors. 'Chapter 2' includes the imaging atmospheric Cherenkov technique (IACT) and the sampling wavefront technique. 'Chapter 3' is dedicated to the detection of the atmospheric nitrogen. 'Chapter 4' describes issues related to the calibration of the detectors, the cross checking of the experimental data, the use of the Monte Carlo simulations and the use of the density observed at a distance of 600 m S(600), in order to estimate the primary energy. The characteristics of some future developments of the above presented techniques are included in the last chapter. (authors)

  17. Air Conditioning Compressor Air Leak Detection by Image Processing Techniques for Industrial Applications

    Directory of Open Access Journals (Sweden)

    Pookongchai Kritsada

    2015-01-01

    Full Text Available This paper presents method to detect air leakage of an air conditioning compressor using image processing techniques. Quality of air conditioning compressor should not have air leakage. To test an air conditioning compressor leak, air is pumped into a compressor and then submerged into the water tank. If air bubble occurs at surface of the air conditioning compressor, that leakage compressor must be returned for maintenance. In this work a new method to detect leakage and search leakage point with high accuracy, fast, and precise processes was proposed. In a preprocessing procedure to detect the air bubbles, threshold and median filter techniques have been used. Connected component labeling technique is used to detect the air bubbles while blob analysis is searching technique to analyze group of the air bubbles in sequential images. The experiments are tested with proposed algorithm to determine the leakage point of an air conditioning compressor. The location of the leakage point was presented as coordinated point. The results demonstrated that leakage point during process could be accurately detected. The estimation point had error less than 5% compared to the real leakage point.

  18. Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes

    Directory of Open Access Journals (Sweden)

    U. Platt

    2011-09-01

    Full Text Available Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2 or sulphuric acid (H2SO4 aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ±40 mrad (2.3° angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the

  19. Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: A feasible aviation safety measure to prevent potential encounters with volcanic plumes

    Science.gov (United States)

    Vogel, L.; Galle, B.; Kern, C.; Delgado, Granados H.; Conde, V.; Norman, P.; Arellano, S.; Landgren, O.; Lubcke, P.; Alvarez, Nieves J.M.; Cardenas, Gonzales L.; Platt, U.

    2011-01-01

    Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized 5 since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in 10 volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to vol- 15 canic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatepetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ±40 mrad (2.3◦) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to 25 the plume and SO2 was measured at all times well above the detection

  20. Safeguards applications of far infrared radiometric techniques for the detection of contraband

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, D.T.; Reber, E.E.; Foote, F.B.; Schellenbaum, R.L.

    1980-02-01

    A new safeguards system under development employs radiometers in the 100 to 300 GHz spectral band to detect contraband, including shielding materials (used to attenuate the gamma ray emissions from nuclear materials), weapons, or explosives covertly concealed on personnel. Clothing is highly transparent at these frequencies and imaging techniques can detect contraband by its emissivity and reflectivity differences relative to human tissues. Experimental data are presented and sample images are used as a basis to discuss system advantages and limitations.

  1. A framework for detection of malicious software in Android handheld systems using machine learning techniques

    OpenAIRE

    Torregrosa García, Blas

    2015-01-01

    The present study aims at designing and developing new approaches to detect malicious applications in Android-based devices. More precisely, MaLDroide (Machine Learning-based Detector for Android malware), a framework for detection of Android malware based on machine learning techniques, is introduced here. It is devised to identify malicious applications. Este trabajo tiene como objetivo el diseño y el desarrollo de nuevas formas de detección de aplicaciones maliciosas en los dispositivos...

  2. Safeguards applications of far infrared radiometric techniques for the detection of contraband

    International Nuclear Information System (INIS)

    Hodges, D.T.; Reber, E.E.; Foote, F.B.; Schellenbaum, R.L.

    1980-02-01

    A new safeguards system under development employs radiometers in the 100 to 300 GHz spectral band to detect contraband, including shielding materials (used to attenuate the gamma ray emissions from nuclear materials), weapons, or explosives covertly concealed on personnel. Clothing is highly transparent at these frequencies and imaging techniques can detect contraband by its emissivity and reflectivity differences relative to human tissues. Experimental data are presented and sample images are used as a basis to discuss system advantages and limitations

  3. Sensitivity of field tests, serological and molecular techniques for Plum Pox Virus detection in various tissues

    Directory of Open Access Journals (Sweden)

    Mojca VIRŠČEK MARN

    2015-12-01

    Full Text Available Sensitivity of field tests (AgriStrip  and Immunochromato, DAS-ELISA, two step RT-PCR and real-time RT-PCR for Plum pox virus (PPV detection was tested in various tissues of apricot, peach, plum and damson plum trees infected with isolates belonging to PPV-D, PPV-M or PPV-Rec, the three strains present in Slovenia. Flowers of apricot and plum in full bloom proved to be a very good source for detection of PPV. PPV could be detected with all tested techniques in symptomatic parts of leaves in May and with one exception even in the beginning of August, but it was not detected in asymptomatic leaves using field tests, DAS-ELISA and partly also molecular techniques. PPV was detected only in some of the samples of asymptomatic parts of the leaves with symptoms and of stalks by field tests and DAS-ELISA. Infections were not detected in buds in August using field tests or DAS-ELISA. Field tests are useful for confirmation of the PPV infection in symptomatic leaves, but in tissues without symptoms DAS-ELISA should be combined or replaced by molecular techniques.

  4. Evaluation of a technique for the intraoperative detection of a radiolabelled monoclonal antibody against colorectal cancer

    International Nuclear Information System (INIS)

    Waddington, W.A.; Todd-Pokropek, A.; Short, M.D.; Davidson, B.R.; Boulos, P.B.; Middlesex Hospital, London

    1991-01-01

    Occult tumour deposits may be localised at operation with a radiation detecting probe following the administration of a radiolabelled monoclonal antibody (MoAb) recognising a tumour-associated antigen. We have recently evaluated the clinical usefulness of this technique in detecting primary colorectal tumours targetted with an indium-111 MoAb. In the present study the physical characteristics of the two detector systems used were investigated; a sodium iodide [NaI(Tl)] scintilation detector and a cadmium telluride (CdTe) semiconductor probe. Limitations of the technique in use have been examined by testing the statistical significance of tumour detecting using an abdominal phantom based on the currently available clinical biodistribution data for tumour uptake of radiolabelled MoAbs. The effect of tumour volume, antibody uptake, collimation and counting conditions was examined. Results indicate that tumours of 10-ml volume may be detected with the NaI(Tl) probe at the lowest levels of radiolabelled antibody uptake currently reported in the literature but that at higher published levels, lesions as small as 1 ml may be identified with both detector systems. Detector sensitivity and limited antibody specificity restrict the usefulness of the technique, although moderate improvements in tumour uptake may allow the detection of tumour deposits not clinically apparent. The statistical significance criterion used for this study could be an accurate and reliable indicator for tumour detection in vivo. (orig.)

  5. Multimodal technique to eliminate humidity interference for specific detection of ethanol.

    Science.gov (United States)

    Jalal, Ahmed Hasnain; Umasankar, Yogeswaran; Gonzalez, Pablo J; Alfonso, Alejandro; Bhansali, Shekhar

    2017-01-15

    Multimodal electrochemical technique incorporating both open circuit potential (OCP) and amperometric techniques have been conceptualized and implemented to improve the detection of specific analyte in systems where more than one analyte is present. This approach has been demonstrated through the detection of ethanol while eliminating the contribution of water in a micro fuel cell sensor system. The sensor was interfaced with LMP91000 potentiostat, controlled through MSP430F5529LP microcontroller to implement an auto-calibration algorithm tailored to improve the detection of alcohol. The sensor was designed and fabricated as a three electrode system with Nafion as a proton exchange membrane (PEM). The electrochemical signal of the interfering phase (water) was eliminated by implementing the multimodal electrochemical detection technique. The results were validated by comparing sensor and potentiostat performances with a commercial sensor and potentiostat respectively. The results suggest that such a sensing system can detect ethanol at concentrations as low as 5ppm. The structure and properties such as low detection limit, selectivity and miniaturized size enables potential application of this device in wearable transdermal alcohol measurements. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. [Demand for and the Development of Detection Techniques for Source of Schistosome Infection in China].

    Science.gov (United States)

    Wang, Shi-ping; He, Xin; Zhou, Yun-fei

    2015-12-01

    Schistosomiasis is a type of zoonotic parasitosis that severely impairs human health. Rapid detection of infection sources is a key to the control of schistosomiasis. With the effective control of schistosomiasis in China, the detection techniques for infection sources have also been developed. The rate and the intensity of infection among humans and livestocks have been significantly decreased in China, as the control program has entered the transmission control stage in most of the endemic areas. Under this situation, the traditional etiological diagnosing techniques and common immunological methods can not afford rapid detection of infection sources of schistosomiasis. Instead, we are calling for detection methods with higher sensitivity, specificity and stability while being less time-consuming, more convenient and less costing. In recent years, many improved or novel detection methods have been applied for the epidemiological surveillance of schistosomiasis, such as the automatic scanning microscopic image acquisition system, PCR-ELISA, immunosensors, loop-mediated isothermal amplification, etc. The development of new monitoring techniques can facilitate rapid detection of schistosome infection sources in endemic areas.

  7. Detection of plant leaf diseases using image segmentation and soft computing techniques

    Directory of Open Access Journals (Sweden)

    Vijai Singh

    2017-03-01

    Full Text Available Agricultural productivity is something on which economy highly depends. This is the one of the reasons that disease detection in plants plays an important role in agriculture field, as having disease in plants are quite natural. If proper care is not taken in this area then it causes serious effects on plants and due to which respective product quality, quantity or productivity is affected. For instance a disease named little leaf disease is a hazardous disease found in pine trees in United States. Detection of plant disease through some automatic technique is beneficial as it reduces a large work of monitoring in big farms of crops, and at very early stage itself it detects the symptoms of diseases i.e. when they appear on plant leaves. This paper presents an algorithm for image segmentation technique which is used for automatic detection and classification of plant leaf diseases. It also covers survey on different diseases classification techniques that can be used for plant leaf disease detection. Image segmentation, which is an important aspect for disease detection in plant leaf disease, is done by using genetic algorithm.

  8. An improved autoradiographic technique for the detection of antibody-forming cells

    International Nuclear Information System (INIS)

    Mason, D.W.

    1976-01-01

    An autoradiographic technique for the detection of antibody-forming cells has been developed for the assay of anti-DNP responses. The lymphoid cell suspension to be assayed was allowed to sediment on to a glass slide coated with DNP-conjugated gelatin to which the secreted antibody bound during subsequent incubation. The bound antibody and its Ig class was revealed by a second incubation using 125 I-anti-immunoglobulin reagents followed by autoradiography. Studies on the sensitivity and specificity of the method are presented and its advantages over other techniques described. The technique should be readily applicable to other haptens

  9. Detection of radiation deformation in crystalline polymers using the speckle photography technique

    International Nuclear Information System (INIS)

    El-Ghandoor, H.; Hashem, A.A.; Sharaf, F.

    1995-01-01

    In order to measure the resulting deformation due to gamma irradiation of polymers, a new optical technique, namely speckle-photography, was established and used. Thin films of tetrafluoroethene, with constant thickness were irradiated by different doses of gamma rays and the diffraction patterns of a laser beam passing through these films were recorded using the speckle photography technique. This technique has been applied to detect the radiation deformation in (Teflon) TFE, which is a crystalline polymer. A diffraction pattern due to the TFE thin layer is obtained and superimposed on the interference pattern displaying the speckle pattern pairs recorded on the same emulsion. (author)

  10. Detection and Sizing of Fatigue Cracks in Steel Welds with Advanced Eddy Current Techniques

    Science.gov (United States)

    Todorov, E. I.; Mohr, W. C.; Lozev, M. G.

    2008-02-01

    Butt-welded specimens were fatigued to produce cracks in the weld heat-affected zone. Advanced eddy current (AEC) techniques were used to detect and size the cracks through a coating. AEC results were compared with magnetic particle and phased-array ultrasonic techniques. Validation through destructive crack measurements was also conducted. Factors such as geometry, surface treatment, and crack tightness interfered with depth sizing. AEC inspection techniques have the potential of providing more accurate and complete sizing flaw data for manufacturing and in-service inspections.

  11. A Review of Ground Target Detection and Classification Techniques in Forward Scattering Radars

    Directory of Open Access Journals (Sweden)

    M. E. A. Kanona

    2018-06-01

    Full Text Available This paper presents a review of target detection and classification in forward scattering radar (FSR which is a special state of bistatic radars, designed to detect and track moving targets in the narrow region along the transmitter-receiver base line. FSR has advantages and incredible features over other types of radar configurations. All previous studies proved that FSR can be used as an alternative system for ground target detection and classification. The radar and FSR fundamentals were addressed and classification algorithms and techniques were debated. On the other hand, the current and future applications and the limitations of FSR were discussed.

  12. Feathering effect detection and artifact agglomeration index-based video deinterlacing technique

    Science.gov (United States)

    Martins, André Luis; Rodrigues, Evandro Luis Linhari; de Paiva, Maria Stela Veludo

    2018-03-01

    Several video deinterlacing techniques have been developed, and each one presents a better performance in certain conditions. Occasionally, even the most modern deinterlacing techniques create frames with worse quality than primitive deinterlacing processes. This paper validates that the final image quality can be improved by combining different types of deinterlacing techniques. The proposed strategy is able to select between two types of deinterlaced frames and, if necessary, make the local correction of the defects. This decision is based on an artifact agglomeration index obtained from a feathering effect detection map. Starting from a deinterlaced frame produced by the "interfield average" method, the defective areas are identified, and, if deemed appropriate, these areas are replaced by pixels generated through the "edge-based line average" method. Test results have proven that the proposed technique is able to produce video frames with higher quality than applying a single deinterlacing technique through getting what is good from intra- and interfield methods.

  13. Detecting the honeycomb sandwich composite material's moisture impregnating defects by using infrared thermography technique

    International Nuclear Information System (INIS)

    Kwon, Koo Ahn; Choi, Man Yong; Park, Jeong Hak; Choi, Won Jae; Park, Hee Sang

    2017-01-01

    Many composite materials are used in the aerospace industry because of their excellent mechanical properties. However, the nature of aviation exposes these materials to high temperature and high moisture conditions depending on climate, location, and altitude. Therefore, the molecular arrangement chemical properties, and mechanical properties of composite materials can be changed under these conditions. As a result, surface disruptions and cracks can be created. Consequently, moisture-impregnating defects can be induced due to the crack and delamination of composite materials as they are repeatedly exposed to moisture absorption moisture release, fatigue environment, temperature changes, and fluid pressure changes. This study evaluates the possibility of detecting the moisture-impregnating defects of CFRP and GFRP honeycomb structure sandwich composite materials, which are the composite materials in the aircraft structure, by using an active infrared thermography technology among non-destructive testing methods. In all experiments, it was possible to distinguish the area and a number of CFRP composite materials more clearly than those of GFRP composite material. The highest detection rate was observed in the heating duration of 50 mHz and the low detection rate was at the heating duration of over 500 mHz. The reflection method showed a higher detection rate than the transmission method

  14. A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms.

    Science.gov (United States)

    Bansod, BabanKumar; Kumar, Tejinder; Thakur, Ritula; Rana, Shakshi; Singh, Inderbir

    2017-08-15

    Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques. The categorization of different electrochemical techniques is done on the basis of different types of detection signals generated due to presence of heavy metal ions in the solution matrix like current, potential, conductivity, electrochemical impedance, and electrochemiluminescence. Also, the recent trends in electrochemical detection of heavy metal ions with various types of sensing platforms including metals, metal films, metal oxides, nanomaterials, carbon nano tubes, polymers, microspheres and biomaterials have been evoked. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Molecular techniques for the identification and detection of microorganisms relevant for the food industry

    NARCIS (Netherlands)

    Klijn, N.

    1996-01-01

    The research described in this thesis concerns the development and application in food microbiology of molecular identification and detection techniques based on 16S rRNA sequences. The technologies developed were applied to study the microbial ecology of two groups of bacteria, namely

  16. Iterative Method of Regularization with Application of Advanced Technique for Detection of Contours

    International Nuclear Information System (INIS)

    Niedziela, T.; Stankiewicz, A.

    2000-01-01

    This paper proposes a novel iterative method of regularization with application of an advanced technique for detection of contours. To eliminate noises, the properties of convolution of functions are utilized. The method can be accomplished in a simple neural cellular network, which creates the possibility of extraction of contours by automatic image recognition equipment. (author)

  17. A comparison of hyperspectral reflectance and fluorescence imaging techniques for detection of contaminants on leafy greens

    Science.gov (United States)

    Ensuring the supply of safe, contaminant free fresh fruit and vegetables is of importance to consumers, suppliers and governments worldwide. In this study, three hyperspectral imaging (HSI) configurations coupled with two multivariate image analysis techniques are compared for detection of fecal con...

  18. Detection of fecal residue on poultry carcasses by laser induced fluorescence imaging techniques

    Science.gov (United States)

    The potential use of laser-induced fluorescence imaging techniques was investigated for the detection of diluted fecal matters from various parts of the digestive tract, including colon, ceca, small intestine, and duodenum, on poultry carcasses. One of the challenges for using fluorescence imaging f...

  19. Development of detection techniques for a single-particle of fissile material(II)

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, S. C.; Kim, W. H.; Park, Y. J.; Song, B. C.; Jeon, Y. S.; Jee, K. Y.; Pyo, H. Y.; Kwack, E. H

    2001-06-01

    The Analytical methods and detection limit of signatures, and the particle discrimination techniques of unknown particles by microscope were investigated in this technical report. In connection with pre-treatment of swipe samples, sampling and treatment of particles, etching method, fission track observation and the preparation of sample for the neutron activation analysis were also described in this thchnical report.

  20. Detection of active faults using data fusion techniques : case study, Psachna Island of Evoia, Greece

    NARCIS (Netherlands)

    Gountromichou, Chrysa; Pohl, Christine; Ehlers, Manfred

    2002-01-01

    The identification of active faults (faults potentially capable to trigger an earthquake) is important for a seismically active country like Greece. Remote sensing techniques and GIS analysis were used in order to detect, map and characterize the tectonic structures of Psachna town and the

  1. Development of detection techniques for a single-particle of fissile material(II)

    International Nuclear Information System (INIS)

    Sohn, S. C.; Kim, W. H.; Park, Y. J.; Song, B. C.; Jeon, Y. S.; Jee, K. Y.; Pyo, H. Y.; Kwack, E. H.

    2001-06-01

    The Analytical methods and detection limit of signatures, and the particle discrimination techniques of unknown particles by microscope were investigated in this technical report. In connection with pre-treatment of swipe samples, sampling and treatment of particles, etching method, fission track observation and the preparation of sample for the neutron activation analysis were also described in this thchnical report

  2. Use of forensic accounting techniques in the detection of fraud in ...

    African Journals Online (AJOL)

    This study investigated the extent of use of forensic accounting techniques in the detection of fraud in tertiary institutions in Anambra State, Nigeria. One research question guided the study and one null hypothesis was tested. Related literature pertinent to the study was reviewed which exposed the need for the study.

  3. Detection of a faint fast-moving near-Earth asteroid using the synthetic tracking technique

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Hallinan, Gregg; Harding, Leon K., E-mail: chengxing.zhai@jpl.nasa.gov [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day{sup –1} and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

  4. Review on Malware and Malware Detection ‎Using Data Mining Techniques

    Directory of Open Access Journals (Sweden)

    Wesam S Bhaya

    2017-11-01

    Full Text Available Malicious software is any type of software or codes which hooks some: private information, data from the computer system, computer operations or(and merely just to do malicious goals of the author on the computer system, without permission of the computer users. (The short abbreviation of malicious software is Malware. However, the detection of malware has become one of biggest issues in the computer security field because of the current communication infrastructures are vulnerable to penetration from many types of malware infection strategies and attacks.  Moreover, malwares are variant and diverse in volume and types and that strictly explode the effectiveness of traditional defense methods like signature approach, which is unable to detect a new malware. However, this vulnerability will lead to a successful computer system penetration (and attack as well as success of more advanced attacks like distributed denial of service (DDoS attack. Data mining methods can be used to overcome limitation of signature-based techniques to detect the zero-day malware. This paper provides an overview of malware and malware detection system using modern techniques such as techniques of data mining approach to detect known and unknown malware samples.

  5. 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.

  6. Voltage switching technique for detecting nuclear spin polarization in a quantum dot

    International Nuclear Information System (INIS)

    Takahashi, Ryo; Kono, Kimitoshi; Tarucha, Seigo; Ono, Keiji

    2010-01-01

    We have introduced a source-drain voltage switching technique for studying nuclear spins in a vertical double quantum dot. Switching the source-drain voltage between the spin-blockade state and the zero-bias Coulomb blockade state can tune the energy difference between the spin singlet and triplet, and effectively turn on/off the hyperfine interaction. Since the change in the nuclear spin state affects the source-drain current, nuclear spin properties can only be detected by transport measurement. Using this technique, we have succeeded in measuring the timescale of nuclear spin depolarization. Furthermore, combining this technique and an RF ac magnetic field, we successfully detected continuous-wave NMR signals of 75 As, 69 Ga, and 71 Ga, which are contained in a quantum dot. (author)

  7. Molecular detection of drug resistance in microbes by isotopic techniques: The IAEA experience

    International Nuclear Information System (INIS)

    Dar, L.; Boussaha, A.; Padhy, A.K.; Khan, B.

    2003-01-01

    The International Atomic Energy Agency (IAEA) supports various programmes on the uses of radionuclide techniques in the management of human communicable diseases. An important issue, being addressed through several technology transfer projects, is the detection of drug resistance in microbes by radioisotope based molecular-biology diagnostic procedures. The techniques employed include dot blot hybridisation with P-32 labelled oligonucleotide probes to detect point mutations, associated with drug resistance, in microbial genes amplified by the polymerase chain reaction (PCR). Molecular methods have been used for the detection of drug resistance in the malarial parasite, Plasmodium falciparum, and in Mycobacterium tuberculosis. Radioisotope based molecular-biology methods have been demonstrated to have comparative advantages in being sensitive, specific, cost-effective, and suitable for application to large-scale molecular surveillance for drug resistance. (author)

  8. A Multi-Agent Framework for Anomalies Detection on Distributed Firewalls Using Data Mining Techniques

    Science.gov (United States)

    Karoui, Kamel; Ftima, Fakher Ben; Ghezala, Henda Ben

    The Agents and Data Mining integration has emerged as a promising area for disributed problems solving. Applying this integration on distributed firewalls will facilitate the anomalies detection process. In this chapter, we present a set of algorithms and mining techniques to analyse, manage and detect anomalies on distributed firewalls' policy rules using the multi-agent approach; first, for each firewall, a static agent will execute a set of data mining techniques to generate a new set of efficient firewall policy rules. Then, a mobile agent will exploit these sets of optimized rules to detect eventual anomalies on a specific firewall (intra-firewalls anomalies) or between firewalls (inter-firewalls anomalies). An experimental case study will be presented to demonstrate the usefulness of our approach.

  9. A novel input-parasitic compensation technique for a nanopore-based CMOS DNA detection sensor

    Science.gov (United States)

    Kim, Jungsuk

    2016-12-01

    This paper presents a novel input-parasitic compensation (IPC) technique for a nanopore-based complementary metal-oxide-semiconductor (CMOS) DNA detection sensor. A resistive-feedback transimpedance amplifier is typically adopted as the headstage of a DNA detection sensor to amplify the minute ionic currents generated from a nanopore and convert them to a readable voltage range for digitization. But, parasitic capacitances arising from the headstage input and the nanopore often cause headstage saturation during nanopore sensing, thereby resulting in significant DNA data loss. To compensate for the unwanted saturation, in this work, we propose an area-efficient and automated IPC technique, customized for a low-noise DNA detection sensor, fabricated using a 0.35- μm CMOS process; we demonstrated this prototype in a benchtop test using an α-hemolysin ( α-HL) protein nanopore.

  10. Detection of nanocrystallinity by X-ray absorption spectroscopy in thin film transition metal/rare-earth atom, elemental and complex oxides

    International Nuclear Information System (INIS)

    Edge, L.F.; Schlom, D.G.; Stemmer, S.; Lucovsky, G.; Luning, J.

    2006-01-01

    Nanocrystallinity has been detected in the X-ray absorption spectra of transition metal and rare-earth oxides by (i) removal of d-state degeneracies in the (a) Ti and Sc L 3 spectra of TiO 2 and LaScO 3 , respectively, and (b) O K 1 spectra of Zr(Hf)O 2 , Y 2 O 3 , LaScO 3 and LaAlO 3 , and by the (ii) detection of the O-atom vacancy in the O K 1 edge ZrO 2 -Y 2 O 3 alloys. Spectroscopic detection is more sensitive than X-ray diffraction with a limit of ∼2 nm as compared to >5 mm. Other example includes detection of ZrO 2 nanocrystallinity in phase-separated Zr(Hf) silicate alloys

  11. Sample preparation for arsenic speciation analysis in baby food by generation of substituted arsines with atomic absorption spectrometry detection

    Czech Academy of Sciences Publication Activity Database

    Huber, C. S.; Vale, M. G. R.; Dessuy, M. B.; Svoboda, Milan; Musil, Stanislav; Dědina, Jiří

    2017-01-01

    Roč. 175, DEC (2017), s. 406 -412 ISSN 0039-9140 R&D Projects: GA MŠk(CZ) LH15174 Institutional support: RVO:68081715 Keywords : slurry sampling * methyl-substituted arsenic species * hydride generation-cryotrapping-atomic absorption spectrometry Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 4.162, year: 2016

  12. Sample preparation for arsenic speciation analysis in baby food by generation of substituted arsines with atomic absorption spectrometry detection

    Czech Academy of Sciences Publication Activity Database

    Huber, C. S.; Vale, M. G. R.; Dessuy, M. B.; Svoboda, Milan; Musil, Stanislav; Dědina, Jiří

    2017-01-01

    Roč. 175, DEC (2017), s. 406-412 ISSN 0039-9140 R&D Projects: GA MŠk(CZ) LH15174 Institutional support: RVO:68081715 Keywords : slurry sampling * methyl-substituted arsenic species * hydride generation-cryotrapping-atomic absorption spectrometry Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 4.162, year: 2016

  13. NEW PERSPECTIVE ON GALAXY OUTFLOWS FROM THE FIRST DETECTION OF BOTH INTRINSIC AND TRAVERSE METAL-LINE ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Kacprzak, Glenn G.; Cooke, Jeff [Swinburne University of Technology, Victoria 3122 (Australia); Martin, Crystal L.; Ho, Stephanie H. [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Bouché, Nicolas; LeReun, Audrey; Schroetter, Ilane [CNRS, Institut de Recherche en Astrophysique et Planétologie (IRAP) de Toulouse, 14 Avenue E. Belin, F-31400 Toulouse (France); Churchill, Christopher W.; Klimek, Elizabeth, E-mail: gkacprzak@astro.swin.edu.au [New Mexico State University, Las Cruces, NM 88003 (United States)

    2014-09-01

    We present the first observation of a galaxy (z = 0.2) that exhibits metal-line absorption back-illuminated by the galaxy (down-the-barrel) and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by Mg II, are blueshifted relative to the galaxy systemic velocity. The quasar sight line, which resides almost directly along the projected minor axis of the galaxy, probes Mg I and Mg II absorption obtained from the Keck/Low Resolution Imaging Spectrometer as well as Lyα, Si II, and Si III absorption obtained from the Hubble Space Telescope/Cosmic Origins Spectrograph. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between V {sub dtb} = 45-255 km s{sup –1}. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities V {sub outflow} = 40-80 km s{sup –1} to reproduce the transverse Mg II absorption kinematics, which is consistent with the range of V {sub dtb}. The galaxy has a metallicity, derived from Hα and N II, of [O/H] = –0.21 ± 0.08, whereas the transverse absorption has [X/H] = –1.12 ± 0.02. The galaxy star formation rate is constrained between 4.6-15 M {sub ☉} yr{sup –1} while the estimated outflow rate ranges between 1.6-4.2 M {sub ☉} yr{sup –1} and yields a wind loading factor ranging between 0.1-0.9. The galaxy and gas metallicities, the galaxy-quasar sight-line geometry, and the down-the-barrel and transverse modeled outflow velocities collectively suggest that the transverse gas originates from ongoing outflowing material from the galaxy. The ∼1 dex decrease in metallicity from the base of the outflow to the outer halo suggests metal dilution of the gas by the time it reached 58 kpc.

  14. Determination of wood burning and fossil fuel contribution of black carbon at Delhi, India using aerosol light absorption technique.

    Science.gov (United States)

    Tiwari, S; Pipal, A S; Srivastava, A K; Bisht, D S; Pandithurai, G

    2015-02-01

    A comprehensive measurement program of effective black carbon (eBC), fine particle (PM2.5), and carbon monoxide (CO) was undertaken during 1 December 2011 to 31 March 2012 (winter period) in Delhi, India. The mean mass concentrations of eBC, PM2.5, and CO were recorded as 12.1 ± 8.7 μg/m(3), 182.75 ± 114.5 μg/m(3), and 3.41 ± 1.6 ppm, respectively, during the study period. Also, the absorption Angstrom exponent (AAE) was estimated from eBC and varied from 0.38 to 1.29 with a mean value of 1.09 ± 0.11. The frequency of occurrence of AAE was ~17 % less than unity whereas ~83 % greater than unity was observed during the winter period in Delhi. The mass concentrations of eBC were found to be higher by ~34 % of the average value of eBC (12.1 μg/m(3)) during the study period. Sources of eBC were estimated, and they were ~94 % from fossil fuel (eBCff) combustion whereas only 6 % was from wood burning (eBCwb). The ratio between eBCff and eBCwb was 15, which indicates a higher impact from fossil fuels compared to biomass burning. When comparing eBCff during day and night, a factor of three higher concentrations was observed in nighttime than daytime, and it is due to combustion of fossil fuel (diesel vehicle emission) and shallow boundary layer conditions. The contribution of eBCwb in eBC was higher between 1800 and 2100 hours due to burning of wood/biomass. A significant correlation between eBC and PM2.5 (r = 0.78) and eBC and CO (r = 0.46) indicates the similarity in location sources. The mass concentration of eBC was highest (23.4 μg/m(3)) during the month of December when the mean visibility (VIS) was lowest (1.31 km). Regression analysis among wind speed (WS), VIS, soot particles, and CO was studied, and significant negative relationships were seen between VIS and eBC (-0.65), eBCff (-0.66), eBCwb (-0.34), and CO (-0.65); however, between WS and eBC (-0.68), eBCff (-0.67), eBCwb (-0.28), and CO (-0.53). The regression analysis indicated

  15. Technique for detecting a small magnitude loss of special nuclear material

    International Nuclear Information System (INIS)

    Pike, D.H.; Chernick, M.R.; Downing, D.J.

    The detection of losses of special nuclear materials has been the subject of much research in recent years. The standard industry practice using ID/LEID will detect large magnitude losses. Time series techniques such as the Kalman Filter or CUSUM methods will detect small magnitude losses if they occur regularly over a sustained period of time. To date no technique has been proposed which adequately addresses the problem of detecting a small magnitude loss occurring in a single period. This paper proposes a method for detecting a small magnitude loss. The approach makes use of the influence function of Hempel. The influence function measures the effect of a single inventory difference on a group of statistics. An inventory difference for a period in which a loss occurs can be expected to produce an abnormality in the calculated statistics. This abnormality is measurable by the influence function. It is shown that a one period loss smaller in magnitude than the LEID can be detected using this approach

  16. Irregular distribution of metal ions in ferrites prepared by co-precipitation technique structure analysis of Mn-Zn ferrite using extended X-ray absorption fine structure

    International Nuclear Information System (INIS)

    Jeyadevan, B.; Tohji, K.; Nakatsuka, K.; Narayanasamy, A.

    2000-01-01

    The tetrahedral/octahedral site occupancy of non-magnetic zinc ion, added to maximize the net magnetic moment of mixed ferrites has been found to depend on the method of preparation. In this paper, we qualitatively analyze the metal ion distribution in Mn-Zn ferrite particles prepared by co-precipitation and ceramic methods using extended X-ray absorption fine structure (EXAFS) technique. The results suggest that the differences observed in the magnetic properties of the samples prepared by different methods are not only due to the difference in particle size but also due to the difference in cation distribution. The difference in cation distributions between ferrites of similar composition prepared differently has been found to depend on the crystal field stability energies of the metal ion of interest and associated cations

  17. Thermal expansion behavior study of Co nanowire array with in situ x-ray diffraction and x-ray absorption fine structure techniques

    Science.gov (United States)

    Mo, Guang; Cai, Quan; Jiang, Longsheng; Wang, Wei; Zhang, Kunhao; Cheng, Weidong; Xing, Xueqing; Chen, Zhongjun; Wu, Zhonghua

    2008-10-01

    In situ x-ray diffraction and x-ray absorption fine structure techniques were used to study the structural change of ordered Co nanowire array with temperature. The results show that the Co nanowires are polycrystalline with hexagonal close packed structure without phase change up until 700 °C. A nonlinear thermal expansion behavior has been found and can be well described by a quadratic equation with the first-order thermal expansion coefficient of 4.3×10-6/°C and the second-order thermal expansion coefficient of 5.9×10-9/°C. The mechanism of this nonlinear thermal expansion behavior is discussed.

  18. Simulation and evaluation of the absorption edge subtraction technique in energy-resolved X-ray radiography applied to the cultural heritage studies

    International Nuclear Information System (INIS)

    Leyva Pernia, Diana; Cabal Rodriguez, Ana E.; Pinnera Hernandez, Ibrahin; Leyva Fabelo, Antonio; Abreu Alfonso, Yamiel; Espen, Piet Van

    2011-01-01

    In this work the mathematical simulation of photon transport in the matter was used to evaluate the potentials of a new energy-resolved X-ray radiography system. The system is intended for investigations of cultural heritage object, mainly painting. The radiographic system uses polychromatic radiation from an X-ray tube and measures the spectrum transmitted through the object with an energy-dispersive X-ray detector on a pixel-by-pixel basis. Manipulation of the data-set obtained allows constructing images with enhanced contrast for certain elements. Here the use of the absorption edge subtraction technique was emphasized. The simulated results were in good agreement with the experimental data.(author)

  19. Molecular detection of pathogens in water--the pros and cons of molecular techniques.

    Science.gov (United States)

    Girones, Rosina; Ferrús, Maria Antonia; Alonso, José Luis; Rodriguez-Manzano, Jesus; Calgua, Byron; Corrêa, Adriana de Abreu; Hundesa, Ayalkibet; Carratala, Anna; Bofill-Mas, Sílvia

    2010-08-01

    Pollution of water by sewage and run-off from farms produces a serious public health problem in many countries. Viruses, along with bacteria and protozoa in the intestine or in urine are shed and transported through the sewer system. Even in highly industrialized countries, pathogens, including viruses, are prevalent throughout the environment. Molecular methods are used to monitor viral, bacterial, and protozoan pathogens, and to track pathogen- and source-specific markers in the environment. Molecular techniques, specifically polymerase chain reaction-based methods, provide sensitive, rapid, and quantitative analytical tools with which to study such pathogens, including new or emerging strains. These techniques are used to evaluate the microbiological quality of food and water, and to assess the efficiency of virus removal in drinking and wastewater treatment plants. The range of methods available for the application of molecular techniques has increased, and the costs involved have fallen. These developments have allowed the potential standardization and automation of certain techniques. In some cases they facilitate the identification, genotyping, enumeration, viability assessment, and source-tracking of human and animal contamination. Additionally, recent improvements in detection technologies have allowed the simultaneous detection of multiple targets in a single assay. However, the molecular techniques available today and those under development require further refinement in order to be standardized and applicable to a diversity of matrices. Water disinfection treatments may have an effect on the viability of pathogens and the numbers obtained by molecular techniques may overestimate the quantification of infectious microorganisms. The pros and cons of molecular techniques for the detection and quantification of pathogens in water are discussed. (c) 2010 Elsevier Ltd. All rights reserved.

  20. On resilience studies of system detection and recovery techniques against stealthy insider attacks

    Science.gov (United States)

    Wei, Sixiao; Zhang, Hanlin; Chen, Genshe; Shen, Dan; Yu, Wei; Pham, Khanh D.; Blasch, Erik P.; Cruz, Jose B.

    2016-05-01

    With the explosive growth of network technologies, insider attacks have become a major concern to business operations that largely rely on computer networks. To better detect insider attacks that marginally manipulate network traffic over time, and to recover the system from attacks, in this paper we implement a temporal-based detection scheme using the sequential hypothesis testing technique. Two hypothetical states are considered: the null hypothesis that the collected information is from benign historical traffic and the alternative hypothesis that the network is under attack. The objective of such a detection scheme is to recognize the change within the shortest time by comparing the two defined hypotheses. In addition, once the attack is detected, a server migration-based system recovery scheme can be triggered to recover the system to the state prior to the attack. To understand mitigation of insider attacks, a multi-functional web display of the detection analysis was developed for real-time analytic. Experiments using real-world traffic traces evaluate the effectiveness of Detection System and Recovery (DeSyAR) scheme. The evaluation data validates the detection scheme based on sequential hypothesis testing and the server migration-based system recovery scheme can perform well in effectively detecting insider attacks and recovering the system under attack.

  1. Molecular basis of structural make-up of feeds in relation to nutrient absorption in ruminants, revealed with advanced molecular spectroscopy: A review on techniques and models

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Md. Mostafizar [Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Yu, Peiqiang [Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

    2017-01-31

    Progress in ruminant feed research is no more feasible only based on wet chemical analysis, which is merely able to provide information on chemical composition of feeds regardless of their digestive features and nutritive value in ruminants. Studying internal structural make-up of functional groups/feed nutrients is often vital for understanding the digestive behaviors and nutritive values of feeds in ruminant because the intrinsic structure of feed nutrients is more related to its overall absorption. In this article, the detail information on the recent developments in molecular spectroscopic techniques to reveal microstructural information of feed nutrients and the use of nutrition models in regards to ruminant feed research was reviewed. The emphasis of this review was on (1) the technological progress in the use of molecular spectroscopic techniques in ruminant feed research; (2) revealing spectral analysis of functional groups of biomolecules/feed nutrients; (3) the use of advanced nutrition models for better prediction of nutrient availability in ruminant systems; and (4) the application of these molecular techniques and combination of nutrient models in cereals, co-products and pulse crop research. The information described in this article will promote better insight in the progress of research on molecular structural make-up of feed nutrients in ruminants.

  2. Energy, exergy, economic (3E) analyses and multi-objective optimization of vapor absorption heat transformer using NSGA-II technique

    International Nuclear Information System (INIS)

    Jain, Vaibhav; Sachdeva, Gulshan

    2017-01-01

    Highlights: • Study includes energy, exergy and economic analyses of absorption heat transformer. • It addresses multi-objective optimization study using NSGA-II technique. • Total annual cost and total exergy destruction are simultaneously optimized. • Results with multi-objective optimized design are more acceptable than other. - Abstract: Present paper addresses the energy, exergy and economic (3E) analyses of absorption heat transformer (AHT) working with LiBr-H 2 O fluid pair. The heat exchangers namely absorber, condenser, evaporator, generator and solution heat exchanger are designed for the size and cost estimation of AHT. Later, the effect of operating variables is examined on the system performance, size and cost. Simulation studies showed a conflict between thermodynamic and economic performance of the system. The heat exchangers with lower investment cost showed high irreversible losses and vice versa. Thus, the operating variables of systems are determined economically as well as thermodynamically by implementing non-dominated sort genetic algorithm-II (NSGA-II) technique of multi-objective optimization. In present work, if the cost based optimized design is chosen, total exergy destruction is 2.4% higher than its minimum possible value; whereas, if total exergy based optimized design is chosen, total annual cost is 6.1% higher than its minimum possible value. On the other hands, total annual cost and total exergy destruction are only 1.0% and 0.8%, respectively more from their minimum possible values with multi-objective optimized design. Thus, the multi-objective optimized design of the AHT is best outcome than any other single-objective optimized designs.

  3. A COMPARISON OF SPECTROSCOPIC VERSUS IMAGING TECHNIQUES FOR DETECTING CLOSE COMPANIONS TO KEPLER OBJECTS OF INTEREST

    Energy Technology Data Exchange (ETDEWEB)

    Teske, Johanna K. [Carnegie DTM, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Everett, Mark E. [National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States); Hirsch, Lea [Astronomy Department, University of California at Berkeley, Berkeley, CA 94720 (United States); Furlan, Elise; Ciardi, David R. [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Ave., Pasadena, CA 91125 (United States); Horch, Elliott P. [Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, CT 06515 (United States); Howell, Steve B. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Gonzales, Erica; Crepp, Justin R., E-mail: jteske@carnegiescience.edu [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States)

    2015-11-15

    Kepler planet candidates require both spectroscopic and imaging follow-up observations to rule out false positives and detect blended stars. Traditionally, spectroscopy and high-resolution imaging have probed different host star companion parameter spaces, the former detecting tight binaries and the latter detecting wider bound companions as well as chance background stars. In this paper, we examine a sample of 11 Kepler host stars with companions detected by two techniques—near-infrared adaptive optics and/or optical speckle interferometry imaging, and a new spectroscopic deblending method. We compare the companion effective temperatures (T{sub eff}) and flux ratios (F{sub B}/F{sub A}, where A is the primary and B is the companion) derived from each technique and find no cases where both companion parameters agree within 1σ errors. In 3/11 cases the companion T{sub eff} values agree within 1σ errors, and in 2/11 cases the companion F{sub B}/F{sub A} values agree within 1σ errors. Examining each Kepler system individually considering multiple avenues (isochrone mapping, contrast curves, probability of being bound), we suggest two cases for which the techniques most likely agree in their companion detections (detect the same companion star). Overall, our results support the advantage that the spectroscopic deblending technique has for finding very close-in companions (θ ≲ 0.″02–0.″05) that are not easily detectable with imaging. However, we also specifically show how high-contrast AO and speckle imaging observations detect companions at larger separations (θ ≥ 0.″02–0.″05) that are missed by the spectroscopic technique, provide additional information for characterizing the companion and its potential contamination (e.g., position angle, separation, magnitude differences), and cover a wider range of primary star effective temperatures. The investigation presented here illustrates the utility of combining the two techniques to reveal higher

  4. Techniques used detection and quantification of aflatoxin M1 in milk

    Directory of Open Access Journals (Sweden)

    Adriana Frizzarin

    2012-02-01

    Full Text Available Aflatoxin is a group of toxic substances produced by fungi, mainly Aspergillus flavus and Aspergillus parasiticus. It can be developed in agriculture products such as grains or processed food, when environment conditions of humidity and air humidity are favorable. Aflatoxins can be presented as several forms. In Milk, are called M1 and M2, resulting from aflatoxins B1 and B2 metabolism. Aflatoxin M1 (AFM1 is classified as a possible carcinogen to humans, so the occurrence of aflatoxin M1 in milk of lactating cows is a public health issue, and because of its importance several techniques are used for its detection and quantification. These techniques include the physical-chemical as thin layer chromatography and high performance liquid chromatography and the biological techniques including immunoassays such as RIA and ELISA. This review aimed to present the techniques used to quantify aflatoxins M1 and M2 in milk and dairy products.

  5. Colour and shape analysis techniques for weed detection in cereal fields

    DEFF Research Database (Denmark)

    Pérez, A.J; López, F; Benlloch, J.V.

    2000-01-01

    . The proposed methods use colour information to discriminate between vegetation and background, whilst shape analysis techniques are applied to distinguish between crop and weeds. The determination of crop row position helps to reduce the number of objects to which shape analysis techniques are applied....... The performance of algorithms was assessed by comparing the results with a human classification, providing an acceptable success rate. The study has shown that despite the difficulties in accurately determining the number of seedlings (as in visual surveys), it is feasible to use image processing techniques......Information on weed distribution within the field is necessary to implement spatially variable herbicide application. This paper deals with the development of near-ground image capture and processing techniques in order to detect broad-leaved weeds in cereal crops under actual field conditions...

  6. Simple lock-in detection technique utilizing multiple harmonics for digital PGC demodulators.

    Science.gov (United States)

    Duan, Fajie; Huang, Tingting; Jiang, Jiajia; Fu, Xiao; Ma, Ling

    2017-06-01

    A simple lock-in detection technique especially suited for digital phase-generated carrier (PGC) demodulators is proposed in this paper. It mixes the interference signal with rectangular waves whose Fourier expansions contain multiple odd or multiple even harmonics of the carrier to recover the quadrature components needed for interference phase demodulation. In this way, the use of a multiplier is avoided and the efficiency of the algorithm is improved. Noise performance with regard to light intensity variation and circuit noise is analyzed theoretically for both the proposed technique and the traditional lock-in technique, and results show that the former provides a better signal-to-noise ratio than the latter with proper modulation depth and average interference phase. Detailed simulations were conducted and the theoretical analysis was verified. A fiber-optic Michelson interferometer was constructed and the feasibility of the proposed technique is demonstrated.

  7. Flow injection on-line dilution for zinc determination in human saliva with electrothermal atomic absorption spectrometry detection

    Energy Technology Data Exchange (ETDEWEB)

    Burguera-Pascu, Margarita [Department of Oral Medicine, School of Dentistry, University of Granada, Granada (Spain)], E-mail: margaburpas@hotmail.com; Rodriguez-Archilla, Alberto [Department of Oral Medicine, School of Dentistry, University of Granada, Granada (Spain); Burguera, Jose Luis; Burguera, Marcela; Rondon, Carlos; Carrero, Pablo [Department of Chemistry, Faculty of Sciences, University of Los Andes, Merida (Venezuela)

    2007-09-26

    An automated method is described for the determination of zinc in human saliva by electrothermal atomic absorption spectrometry (ET AAS) after on-line dilution of samples with a significant reduction of sample consumption per analysis (<0.4 mL including the dead volume of the system). In order to fulfill this aim without changing the sample transport conduits during the experiments, a flow injection (FI) dilution system was constructed. Its principal parts are: one propulsion device (peristaltic pump, PP) for either samples, standards or washing solution all located in an autosampler tray and for the surfactant solution (Triton X-100) used as diluent, and a two-position time based solenoid injector (TBSI{sub 1}) which allowed the introduction of 10 {mu}L of either solution in the diluent stream. To avoid unnecessary waste of samples, the TBSI{sub 1} also permitted the recirculation of the solutions to their respective autosampler cups. The downstream diluted solution fills a home made sampling arm assembly. The sequential deposition of 20 {mu}L aliquots of samples or standards on the graphite tube platform was carried out by air displacement with a similar time based solenoid injector (TBSI{sub 2}). The dilution procedure and the injection of solutions into the atomizer are computer controlled and synchronized with the operation of the temperature program. Samples or standards solutions were submitted to two drying steps (at 90 and 130 deg. C), followed by pyrolysis and atomization at 700 and 1700 deg. C, respectively. The aqueous calibration was linear up to 120.0 {mu}g L{sup -1} for diluted standard solutions/samples and its slope was similar (p > 0.05) to the standard addition curve, indicating lack of matrix effect. The precision tested by repeated analysis of real saliva samples was less than 3% and the detection limit (3{sigma}) was of 0.35 {mu}g L{sup -1}. To test the accuracy of the proposed procedure, recovery tests were performed, obtaining mean recovery

  8. Lesion Detection in CT Images Using Deep Learning Semantic Segmentation Technique

    Science.gov (United States)

    Kalinovsky, A.; Liauchuk, V.; Tarasau, A.

    2017-05-01

    In this paper, the problem of automatic detection of tuberculosis lesion on 3D lung CT images is considered as a benchmark for testing out algorithms based on a modern concept of Deep Learning. For training and testing of the algorithms a domestic dataset of 338 3D CT scans of tuberculosis patients with manually labelled lesions was used. The algorithms which are based on using Deep Convolutional Networks were implemented and applied in three different ways including slice-wise lesion detection in 2D images using semantic segmentation, slice-wise lesion detection in 2D images using sliding window technique as well as straightforward detection of lesions via semantic segmentation in whole 3D CT scans. The algorithms demonstrate superior performance compared to algorithms based on conventional image analysis methods.

  9. Acoustic emission technique for leak detection in an end shield of a pressurized heavy water reactor

    International Nuclear Information System (INIS)

    Kalyanasundaram, P.; Jayakumar, T.; Raj, B.

    1989-01-01

    This paper discusses the successful application of the Acoustic Emission Technique (AET) for detection and location of leak paths present on the inaccessible side of an end shield of a Pressurized Heavy Water Reactor (PHWR). The methodology was based on the fact that air and water leak AE signals have different characteristic features. Baseline data was generated from a sound end-shield of a PHWR for characterizing the background noise. A mock up end-shield system with saw cut leak paths was used to verify the validity of the methodology. It was found that air leak signals under pressurisation (as low as 3 psi) could be detected by frequency domain analysis. Signals due to air leaks from various locations of a defective end-shield were acquired and analysed. It was possible to detect and locate leak paths. Presence of detected leak paths were further confirmed by alternate test. (orig.)

  10. Automatic detection of health changes using statistical process control techniques on measured transfer times of elderly.

    Science.gov (United States)

    Baldewijns, Greet; Luca, Stijn; Nagels, William; Vanrumste, Bart; Croonenborghs, Tom

    2015-01-01

    It has been shown that gait speed and transfer times are good measures of functional ability in elderly. However, data currently acquired by systems that measure either gait speed or transfer times in the homes of elderly people require manual reviewing by healthcare workers. This reviewing process is time-consuming. To alleviate this burden, this paper proposes the use of statistical process control methods to automatically detect both positive and negative changes in transfer times. Three SPC techniques: tabular CUSUM, standardized CUSUM and EWMA, known for their ability to detect small shifts in the data, are evaluated on simulated transfer times. This analysis shows that EWMA is the best-suited method with a detection accuracy of 82% and an average detection time of 9.64 days.

  11. WRHT: A Hybrid Technique for Detection of Wormhole Attack in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Rupinder Singh

    2016-01-01

    Full Text Available Wormhole attack is a challenging security threat to wireless sensor networks which results in disrupting most of the routing protocols as this attack can be triggered in different modes. In this paper, WRHT, a wormhole resistant hybrid technique, is proposed, which can detect the presence of wormhole attack in a more optimistic manner than earlier techniques. WRHT is based on the concept of watchdog and Delphi schemes and ensures that the wormhole will not be left untreated in the sensor network. WRHT makes use of the dual wormhole detection mechanism of calculating probability factor time delay probability and packet loss probability of the established path in order to find the value of wormhole presence probability. The nodes in the path are given different ranking and subsequently colors according to their behavior. The most striking feature of WRHT consists of its capacity to defend against almost all categories of wormhole attacks without depending on any required additional hardware such as global positioning system, timing information or synchronized clocks, and traditional cryptographic schemes demanding high computational needs. The experimental results clearly indicate that the proposed technique has significant improvement over the existing wormhole attack detection techniques.

  12. A COMPARATIVE ANALYSIS OF SINGLE AND COMBINATION FEATURE EXTRACTION TECHNIQUES FOR DETECTING CERVICAL CANCER LESIONS

    Directory of Open Access Journals (Sweden)

    S. Pradeep Kumar Kenny

    2016-02-01

    Full Text Available Cervical cancer is the third most common form of cancer affecting women especially in third world countries. The predominant reason for such alarming rate of death is primarily due to lack of awareness and proper health care. As they say, prevention is better than cure, a better strategy has to be put in place to screen a large number of women so that an early diagnosis can help in saving their lives. One such strategy is to implement an automated system. For an automated system to function properly a proper set of features have to be extracted so that the cancer cell can be detected efficiently. In this paper we compare the performances of detecting a cancer cell using a single feature versus a combination feature set technique to see which will suit the automated system in terms of higher detection rate. For this each cell is segmented using multiscale morphological watershed segmentation technique and a series of features are extracted. This process is performed on 967 images and the data extracted is subjected to data mining techniques to determine which feature is best for which stage of cancer. The results thus obtained clearly show a higher percentage of success for combination feature set with 100% accurate detection rate.

  13. A SIMULTANEOUS MULTI-PROBE DETECTION LABEL-FREE OPTICAL-RESOLUTION PHOTOACOUSTIC MICROSCOPY TECHNIQUE BASED ON MICROCAVITY TRANSDUCER

    Directory of Open Access Journals (Sweden)

    YONGBO WU

    2013-07-01

    Full Text Available We demonstrate the feasibility of simultaneous multi-probe detection for an optical-resolution photoacoustic microscopy (OR-PAM system. OR-PAM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth. OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules. However, given the inadequate absorption of some biomolecules, detection sensitivity at the same incident intensity requires improvement. In this study, a modulated continuous wave with power density less than 3 mW/cm2 (1/4 of the ANSI safety limit excited the weak photoacoustic (PA signals of biological cells. A microcavity transducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid; air pressure variation is inversely proportional to cavity volume at the same temperature increase. Considering that a PA wave expands in various directions, detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio. Therefore, we employ four detectors to acquire tiny PA signals simultaneously. Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.

  14. Improved Statistical Fault Detection Technique and Application to Biological Phenomena Modeled by S-Systems.

    Science.gov (United States)

    Mansouri, Majdi; Nounou, Mohamed N; Nounou, Hazem N

    2017-09-01

    In our previous work, we have demonstrated the effectiveness of the linear multiscale principal component analysis (PCA)-based moving window (MW)-generalized likelihood ratio test (GLRT) technique over the classical PCA and multiscale principal component analysis (MSPCA)-based GLRT methods. The developed fault detection algorithm provided optimal properties by maximizing the detection probability for a particular false alarm rate (FAR) with different values of windows, and however, most real systems are nonlinear, which make the linear PCA method not able to tackle the issue of non-linearity to a great extent. Thus, in this paper, first, we apply a nonlinear PCA to obtain an accurate principal component of a set of data and handle a wide range of nonlinearities using the kernel principal component analysis (KPCA) model. The KPCA is among the most popular nonlinear statistical methods. Second, we extend the MW-GLRT technique to one that utilizes exponential weights to residuals in the moving window (instead of equal weightage) as it might be able to further improve fault detection performance by reducing the FAR using exponentially weighed moving average (EWMA). The developed detection method, which is called EWMA-GLRT, provides improved properties, such as smaller missed detection and FARs and smaller average run length. The idea behind the developed EWMA-GLRT is to compute a new GLRT statistic that integrates current and previous data information in a decreasing exponential fashion giving more weight to the more recent data. This provides a more accurate estimation of the GLRT statistic and provides a stronger memory that will enable better decision making with respect to fault detection. Therefore, in this paper, a KPCA-based EWMA-GLRT method is developed and utilized in practice to improve fault detection in biological phenomena modeled by S-systems and to enhance monitoring process mean. The idea behind a KPCA-based EWMA-GLRT fault detection algorithm is to

  15. A Wearable Gait Phase Detection System Based on Force Myography Techniques

    Directory of Open Access Journals (Sweden)

    Xianta Jiang

    2018-04-01

    Full Text Available (1 Background: Quantitative evaluation of gait parameters can provide useful information for constructing individuals’ gait profile, diagnosing gait abnormalities, and better planning of rehabilitation schemes to restore normal gait pattern. Objective determination of gait phases in a gait cycle is a key requirement in gait analysis applications; (2 Methods: In this study, the feasibility of using a force myography-based technique for a wearable gait phase detection system is explored. In this regard, a force myography band is developed and tested with nine participants walking on a treadmill. The collected force myography data are first examined sample-by-sample and classified into four phases using Linear Discriminant Analysis. The gait phase events are then detected from these classified samples using a set of supervisory rules; (3 Results: The results show that the force myography band can correctly detect more than 99.9% of gait phases with zero insertions and only four deletions over 12,965 gait phase segments. The average temporal error of gait phase detection is 55.2 ms, which translates into 2.1% error with respect to the corresponding labelled stride duration; (4 Conclusions: This proof-of-concept study demonstrates the feasibility of force myography techniques as viable solutions in developing wearable gait phase detection systems.

  16. Multiplexed wavelet transform technique for detection of microcalcification in digitized mammograms.

    Science.gov (United States)

    Mini, M G; Devassia, V P; Thomas, Tessamma

    2004-12-01

    Wavelet transform (WT) is a potential tool for the detection of microcalcifications, an early sign of breast cancer. This article describes the implementation and evaluates the performance of two novel WT-based schemes for the automatic detection of clustered microcalcifications in digitized mammograms. Employing a one-dimensional WT technique that utilizes the pseudo-periodicity property of image sequences, the proposed algorithms achieve high detection efficiency and low processing memory requirements. The detection is achieved from the parent-child relationship between the zero-crossings [Marr-Hildreth (M-H) detector] /local extrema (Canny detector) of the WT coefficients at different levels of decomposition. The detected pixels are weighted before the inverse transform is computed, and they are segmented by simple global gray level thresholding. Both detectors produce 95% detection sensitivity, even though there are more false positives for the M-H detector. The M-H detector preserves the shape information and provides better detection sensitivity for mammograms containing widely distributed calcifications.

  17. Detection of drugs and explosives using neutron computerized tomography and artificial intelligence techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, F.J.O. [Instituto de Engenharia Nuclear, Cidade Universitaria, Rio de Janeiro, CEP 21945-970, Caixa Postal 68550 (Brazil)], E-mail: fferreira@ien.gov.br; Crispim, V.R.; Silva, A.X. [DNC/Poli, PEN COPPE CT, UFRJ Universidade Federal do Rio de Janeiro, CEP 21941-972, Caixa Postal 68509, Rio de Janeiro (Brazil)

    2010-06-15

    In this study the development of a methodology to detect illicit drugs and plastic explosives is described with the objective of being applied in the realm of public security. For this end, non-destructive assay with neutrons was used and the technique applied was the real time neutron radiography together with computerized tomography. The system is endowed with automatic responses based upon the application of an artificial intelligence technique. In previous tests using real samples, the system proved capable of identifying 97% of the inspected materials.

  18. Discussions in symposium 'neutron dosimetry in neutron fields - from detection techniques to medical applications'

    International Nuclear Information System (INIS)

    Tanimura, Y.; Sato, T.; Kumada, H.; Terunuma, T.; Sakae, T.; Harano, H.; Matsumoto, T.; Suzuki, T.; Matsufuji, N.

    2008-01-01

    Recently the traceability system (JCSS) of neutron standard based on the Japanese law 'Measurement Act' has been instituted. In addition, importance of the neutron dose evaluation has been increasing in not only the neutron capture medical treatment but also the proton or heavy particle therapy. Against such a background, a symposium 'Neutron dosimetry in neutron fields - From detection techniques to medical applications-' was held on March 29, 2008 and recent topics on the measuring instruments and their calibration, the traceability system, the simulation technique and the medical applications were introduced. This article summarizes the key points in the discussion at the symposium. (author)

  19. Detection of drugs and explosives using neutron computerized tomography and artificial intelligence techniques

    International Nuclear Information System (INIS)

    Ferreira, F.J.O.; Crispim, V.R.; Silva, A.X.

    2010-01-01

    In this study the development of a methodology to detect illicit drugs and plastic explosives is described with the objective of being applied in the realm of public security. For this end, non-destructive assay with neutrons was used and the technique applied was the real time neutron radiography together with computerized tomography. The system is endowed with automatic responses based upon the application of an artificial intelligence technique. In previous tests using real samples, the system proved capable of identifying 97% of the inspected materials.

  20. Biophysical Techniques for Detection of cAMP and cGMP in Living Cells

    Directory of Open Access Journals (Sweden)

    Viacheslav O. Nikolaev

    2013-04-01

    Full Text Available Cyclic nucleotides cAMP and cGMP are ubiquitous second messengers which regulate myriads of functions in virtually all eukaryotic cells. Their intracellular effects are often mediated via discrete subcellular signaling microdomains. In this review, we will discuss state-of-the-art techniques to measure cAMP and cGMP in biological samples with a particular focus on live cell imaging approaches, which allow their detection with high temporal and spatial resolution in living cells and tissues. Finally, we will describe how these techniques can be applied to the analysis of second messenger dynamics in subcellular signaling microdomains.

  1. Filtering technique for detection and identification of measurement failures in nuclear power plants

    International Nuclear Information System (INIS)

    Racz, A.

    1989-11-01

    The basic requirement of the safe operation of nuclear power plants (NPP) is to have reliable information on all quantities that can be measured, monitored or controlled during the operation. Kalman filtering techniques have been applied for prompt detection and identification of failures in the measurement systems used in NPPs. Mathematical basis of Kalman filtering and various models applied to failure detection are overviewed. The applicability of some models are evaluated by real results of NPP measurements. A sample system for an NPP is suggested, based on several numerical tests. (R.P.) 23 refs.; 40 figs.; 2 tabs

  2. A novel wavelet neural network based pathological stage detection technique for an oral precancerous condition

    Science.gov (United States)

    Paul, R R; Mukherjee, A; Dutta, P K; Banerjee, S; Pal, M; Chatterjee, J; Chaudhuri, K; Mukkerjee, K

    2005-01-01

    Aim: To describe a novel neural network based oral precancer (oral submucous fibrosis; OSF) stage detection method. Method: The wavelet coefficients of transmission electron microscopy images of collagen fibres from normal oral submucosa and OSF tissues were used to choose the feature vector which, in turn, was used to train the artificial neural network. Results: The trained network was able to classify normal and oral precancer stages (less advanced and advanced) after obtaining the image as an input. Conclusions: The results obtained from this proposed technique were promising and suggest that with further optimisation this method could be used to detect and stage OSF, and could be adapted for other conditions. PMID:16126873

  3. Remote sensing techniques for the detection of soil erosion and the identification of soil conservation practices

    Science.gov (United States)

    Pelletier, R. E.; Griffin, R. H.

    1985-01-01

    The following paper is a summary of a number of techniques initiated under the AgRISTARS (Agriculture and Resources Inventory Surveys Through Aerospace Remote Sensing) project for the detection of soil degradation caused by water erosion and the identification of soil conservation practices for resource inventories. Discussed are methods to utilize a geographic information system to determine potential soil erosion through a USLE (Universal Soil Loss Equation) model; application of the Kauth-Thomas Transform to detect present erosional status; and the identification of conservation practices through visual interpretation and a variety of enhancement procedures applied to digital remotely sensed data.

  4. 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

  5. Recent advances in sample preparation techniques and methods of sulfonamides detection - A review.

    Science.gov (United States)

    Dmitrienko, Stanislava G; Kochuk, Elena V; Apyari, Vladimir V; Tolmacheva, Veronika V; Zolotov, Yury A

    2014-11-19

    Sulfonamides (SAs) have been the most widely used antimicrobial drugs for more than 70 years, and their residues in foodstuffs and environmental samples pose serious health hazards. For this reason, sensitive and specific methods for the quantification of these compounds in numerous matrices have been developed. This review intends to provide an updated overview of the recent trends over the past five years in sample preparation techniques and methods for detecting SAs. Examples of the sample preparation techniques, including liquid-liquid and solid-phase extraction, dispersive liquid-liquid microextraction and QuEChERS, are given. Different methods of detecting the SAs present in food and feed and in environmental, pharmaceutical and biological samples are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Detection of irradiated spices using photo-stimulated luminescence technique (PSL)

    Energy Technology Data Exchange (ETDEWEB)

    Ramli, Ros Anita Ahmad; Yasir, Muhamad Samudi [Faculty of Science and Technology, National University of Malaysia, Bangi, 43000 Kajang, Selangor (Malaysia); Othman, Zainon; Abdullah, Wan Saffiey Wan [Malaysian Nuclear Agency, Bangi 43000 Kajang, Selangor (Malaysia)

    2014-09-03

    Photo-stimulated luminescence (PSL) technique was applied to detect irradiated black pepper (Piper nigrum), cinnamon (Cinnamomum verum) and turmeric (Curcuma longa) after dark storage for 1 day, 3 and 6 months. Using screening and calibrated PSL, all samples were correctly discriminated between non-irradiated and spices irradiated with doses 1, 5 and 10 kGy. The PSL photon counts (PCs) of irradiated spices increased with increasing dose, with turmeric showing highest sensitivity index to irradiation compared to black pepper and cinnamon. The differences in response are possibly attributed to the varying quantity and quality of silicate minerals present in each spice sample. PSL signals of all irradiated samples reduced after 3 and 6 months storage. The results of this study provide a useful database on the applicability of PSL technique for the detection of Malaysian irradiated spices.

  7. Detection of Cavities by Inverse Heat Conduction Boundary Element Method Using Minimal Energy Technique

    International Nuclear Information System (INIS)

    Choi, C. Y.

    1997-01-01

    A geometrical inverse heat conduction problem is solved for the infrared scanning cavity detection by the boundary element method using minimal energy technique. By minimizing the kinetic energy of temperature field, boundary element equations are converted to the quadratic programming problem. A hypothetical inner boundary is defined such that the actual cavity is located interior to the domain. Temperatures at hypothetical inner boundary are determined to meet the constraints of measurement error of surface temperature obtained by infrared scanning, and then boundary element analysis is performed for the position of an unknown boundary (cavity). Cavity detection algorithm is provided, and the effects of minimal energy technique on the inverse solution method are investigated by means of numerical analysis

  8. Detection of Moving Targets Based on Doppler Spectrum Analysis Technique for Passive Coherent Radar

    Directory of Open Access Journals (Sweden)

    Zhao Yao-dong

    2013-06-01

    Full Text Available A novel method of moving targets detection taking Doppler spectrum analysis technique for Passive Coherent Radar (PCR is provided. After dividing the receiving signals into segments as pulse series, it utilizes the technique of pulse compress and Doppler processing to detect and locate the targets. Based on the algorithm for Pulse-Doppler (PD radar, the equipollence between continuous and pulsed wave in match filtering is proved and details of this method are introduced. To compare it with the traditional method of Cross-Ambiguity Function (CAF calculation, the relationship and mathematical modes of them are analyzed, with some suggestions on parameters choosing. With little influence to the gain of targets, the method can greatly promote the processing efficiency. The validity of the proposed method is demonstrated by offline processing real collected data sets and simulation results.

  9. Detection of irradiated spices using photo-stimulated luminescence technique (PSL)

    Science.gov (United States)

    Ramli, Ros Anita Ahmad; Yasir, Muhamad Samudi; Othman, Zainon; Abdullah, Wan Saffiey Wan

    2014-09-01

    Photo-stimulated luminescence (PSL) technique was applied to detect irradiated black pepper (Piper nigrum), cinnamon (Cinnamomum verum) and turmeric (Curcuma longa) after dark storage for 1 day, 3 and 6 months. Using screening and calibrated PSL, all samples were correctly discriminated between non-irradiated and spices irradiated with doses 1, 5 and 10 kGy. The PSL photon counts (PCs) of irradiated spices increased with increasing dose, with turmeric showing highest sensitivity index to irradiation compared to black pepper and cinnamon. The differences in response are possibly attributed to the varying quantity and quality of silicate minerals present in each spice sample. PSL signals of all irradiated samples reduced after 3 and 6 months storage. The results of this study provide a useful database on the applicability of PSL technique for the detection of Malaysian irradiated spices.

  10. Detection of irradiated spices using photo-stimulated luminescence technique (PSL)

    International Nuclear Information System (INIS)

    Ramli, Ros Anita Ahmad; Yasir, Muhamad Samudi; Othman, Zainon; Abdullah, Wan Saffiey Wan

    2014-01-01

    Photo-stimulated luminescence (PSL) technique was applied to detect irradiated black pepper (Piper nigrum), cinnamon (Cinnamomum verum) and turmeric (Curcuma longa) after dark storage for 1 day, 3 and 6 months. Using screening and calibrated PSL, all samples were correctly discriminated between non-irradiated and spices irradiated with doses 1, 5 and 10 kGy. The PSL photon counts (PCs) of irradiated spices increased with increasing dose, with turmeric showing highest sensitivity index to irradiation compared to black pepper and cinnamon. The differences in response are possibly attributed to the varying quantity and quality of silicate minerals present in each spice sample. PSL signals of all irradiated samples reduced after 3 and 6 months storage. The results of this study provide a useful database on the applicability of PSL technique for the detection of Malaysian irradiated spices

  11. UV laser long-path absorption spectroscopy

    Science.gov (United States)

    Dorn, Hans-Peter; Brauers, Theo; Neuroth, Rudolf

    1994-01-01

    Long path Differential Optical Absorption Spectroscopy (DOAS) using a picosecond UV laser as a light source was developed in our institute. Tropospheric OH radicals are measured by their rotational absorption lines around 308 nm. The spectra are obtained using a high resolution spectrograph. The detection system has been improved over the formerly used optomechanical scanning device by application of a photodiode array which increased the observed spectral range by a factor of 6 and which utilizes the light much more effectively leading to a considerable reduction of the measurement time. This technique provides direct measurements of OH because the signal is given by the product of the absorption coefficient and the OH concentration along the light path according to Lambert-Beers law. No calibration is needed. Since the integrated absorption coefficient is well known the accuracy of the measurement essentially depends on the extent to which the OH absorption pattern can be detected in the spectra. No interference by self generated OH radicals in the detection lightpath has been observed. The large bandwidth (greater than 0.15 nm) and the high spectral resolution (1.5 pm) allows absolute determination of interferences by other trace gas absorptions. The measurement error is directly accessible from the absorption-signal to baseline-noise ratio in the spectra. The applicability of the method strongly depends on visibility. Elevated concentrations of aerosols lead to considerable attenuation of the laser light which reduces the S/N-ratio. In the moderately polluted air of Julich, where we performed a number of OH measurement spectra. In addition absorption features of unidentified species were frequently detected. A quantitative deconvolution even of the known species is not easy to achieve and can leave residual structures in the spectra. Thus interferences usually increase the noise and deteriorate the OH detection sensitivity. Using diode arrays for sensitive

  12. Molecular profiling techniques as tools to detect potential unintended effects in genetically engineered maize

    CSIR Research Space (South Africa)

    Barros, E

    2010-05-01

    Full Text Available Molecular Profiling Techniques as Tools to Detect Potential Unintended Effects in Genetically Engineered Maize Eugenia Barros Introduction In the early stages of production and commercialization of foods derived from genetically engineered (GE) plants... systems. In a recent paper published in Plant Biotechnology Journal,4 we compared two transgenic white maize lines with the non-transgenic counterpart to investigate two possible sources of variation: genetic engineering and environmental variation...

  13. Detection and identification of explosives and illicit drugs using neutron based techniques

    International Nuclear Information System (INIS)

    Papp, A.; Csikai, J.; Debrecen University,

    2011-01-01

    Some methods developed in collaboration between the ATOMKI and IEP for bulk hydrogen analysis and for the detection and identification of illicit drugs are presented. Advantages and limitations of neutron techniques (reflection, transmission, elastic and inelastic scatterings, leakage spectra and angular yields of Be(d,n), Pu-Be, D-D, D-T and 252 Cf neutrons transmitted from thick samples, effects of hidden materials) are discussed. (author)

  14. Thermo-economic and environmental analyses based multi-objective optimization of vapor compression–absorption cascaded refrigeration system using NSGA-II technique

    International Nuclear Information System (INIS)

    Jain, Vaibhav; Sachdeva, Gulshan; Kachhwaha, Surendra Singh; Patel, Bhavesh

    2016-01-01

    Highlights: • It addresses multi-objective optimization study on cascaded refrigeration system. • Cascaded system is a promising decarburizing and energy efficient technology. • NSGA-II technique is used for multi-objective optimization. • Total annual product cost and irreversibility rate are simultaneously optimized. - Abstract: Present work optimizes the performance of 170 kW vapor compression–absorption cascaded refrigeration system (VCACRS) based on combined thermodynamic, economic and environmental parameters using Non-dominated Sort Genetic Algorithm-II (NSGA-II) technique. Two objective functions including the total irreversibility rate (as a thermodynamic criterion) and the total product cost (as an economic criterion) of the system are considered simultaneously for multi-objective optimization of VCACRS. The capital and maintenance costs of the system components, the operational cost, and the penalty cost due to CO_2 emission are included in the total product cost of the system. Three optimized systems including a single-objective thermodynamic optimized, a single-objective economic optimized and a multi-objective optimized are analyzed and compared. The results showed that the multi-objective design considers the combined thermodynamic and total product cost criteria better than the two individual single-objective thermodynamic and total product cost optimized designs.

  15. The role of sentinel node detection techniques in vulvar and cervival cancer

    International Nuclear Information System (INIS)

    Wydra, D.; Sawicki, S.; Emerich, J.; Romanowicz, G.

    2002-01-01

    The sentinel node is the first lymph node that receives the lymph drainage from the primary tumour. The pathological status of the sentinel node should reflect the histopathology of the entire regional lymph drainage area - both vulvar and cervical cancer spread through the lymphatic system. In gynaecological oncology recent studies have confirmed the utility of the sentinel node concept in vulvar and cervical cancer. Three techniques for sentinel node localisation are available. The preoperative lymphoscintigraphy and intraoperative handheld gamma probe detection require the administration of the technetium-99m-labelled colloid around the tumour. The other method is based on the injection of the patent blue dye - during the surgery of the sentinel node because of the dye uptake becomes visible. Following detection, the sentinel lymph node can be removed separately and assessed with ultrastaging and immunohistochemical staining. In the early stages of vulvar and cervical cancer the lymph nodes metastases rate is relatively low - in most cases lymphadenectomy is not necessary. The determination of the regional lymph nodes' pathological status may limit the extent of the surgical treatment. The sentinel node detection rate is relatively high and depends on the applied technique. This technique may play an important role in the treatment of vulvar and cervical cancer. This paper describes the details of sentinel node identification and reviews the literature. (author)

  16. Biosensor-based microRNA detection: techniques, design, performance, and challenges.

    Science.gov (United States)

    Johnson, Blake N; Mutharasan, Raj

    2014-04-07

    The current state of biosensor-based techniques for amplification-free microRNA (miRNA) detection is critically reviewed. Comparison with non-sensor and amplification-based molecular techniques (MTs), such as polymerase-based methods, is made in terms of transduction mechanism, associated protocol, and sensitivity. Challenges associated with miRNA hybridization thermodynamics which affect assay selectivity and amplification bias are briefly discussed. Electrochemical, electromechanical, and optical classes of miRNA biosensors are reviewed in terms of transduction mechanism, limit of detection (LOD), time-to-results (TTR), multiplexing potential, and measurement robustness. Current trends suggest that biosensor-based techniques (BTs) for miRNA assay will complement MTs due to the advantages of amplification-free detection, LOD being femtomolar (fM)-attomolar (aM), short TTR, multiplexing capability, and minimal sample preparation requirement. Areas of future importance in miRNA BT development are presented which include focus on achieving high measurement confidence and multiplexing capabilities.

  17. Copy-Move Forgery Detection Technique for Forensic Analysis in Digital Images

    Directory of Open Access Journals (Sweden)

    Toqeer Mahmood

    2016-01-01

    Full Text Available Due to the powerful image editing tools images are open to several manipulations; therefore, their authenticity is becoming questionable especially when images have influential power, for example, in a court of law, news reports, and insurance claims. Image forensic techniques determine the integrity of images by applying various high-tech mechanisms developed in the literature. In this paper, the images are analyzed for a particular type of forgery where a region of an image is copied and pasted onto the same image to create a duplication or to conceal some existing objects. To detect the copy-move forgery attack, images are first divided into overlapping square blocks and DCT components are adopted as the block representations. Due to the high dimensional nature of the feature space, Gaussian RBF kernel PCA is applied to achieve the reduced dimensional feature vector representation that also improved the efficiency during the feature matching. Extensive experiments are performed to evaluate the proposed method in comparison to state of the art. The experimental results reveal that the proposed technique precisely determines the copy-move forgery even when the images are contaminated with blurring, noise, and compression and can effectively detect multiple copy-move forgeries. Hence, the proposed technique provides a computationally efficient and reliable way of copy-move forgery detection that increases the credibility of images in evidence centered applications.

  18. Fungal disease detection in plants: Traditional assays, novel diagnostic techniques and biosensors.

    Science.gov (United States)

    Ray, Monalisa; Ray, Asit; Dash, Swagatika; Mishra, Abtar; Achary, K Gopinath; Nayak, Sanghamitra; Singh, Shikha

    2017-01-15

    Fungal diseases in commercially important plants results in a significant reduction in both quality and yield, often leading to the loss of an entire plant. In order to minimize the losses, it is essential to detect and identify the pathogens at an early stage. Early detection and accurate identification of pathogens can control the spread of infection. The present article provides a comprehensive overview of conventional methods, current trends and advances in fungal pathogen detection with an emphasis on biosensors. Traditional techniques are the "gold standard" in fungal detection which relies on symptoms, culture-based, morphological observation and biochemical identifications. In recent times, with the advancement of biotechnology, molecular and immunological approaches have revolutionized fungal disease detection. But the drawback lies in the fact that these methods require specific and expensive equipments. Thus, there is an urgent need for rapid, reliable, sensitive, cost effective and easy to use diagnostic methods for fungal pathogen detection. Biosensors would become a promising and attractive alternative, but they still have to be subjected to some modifications, improvements and proper validation for on-field use. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. A review of repeat prostate biopsies and the influence of technique on cancer detection: our experience.

    LENUS (Irish Health Repository)

    Quinlan, M R

    2012-02-01

    BACKGROUND: Follow-up of patients with an initial negative prostate biopsy, but surrounding whom a suspicion of prostate cancer persists, is difficult. In addition, debate exists as to the optimal technique for repeat prostate biopsy. AIMS: To assess the cancer detection rate on repeat prostate biopsy. METHODS: We reviewed patients who underwent prostate biopsy in our department in 2005 who had >or=1 previous biopsy within the preceding 5 years. Cancer detection rate on repeat biopsy and the influence of the number of biopsy cores were recorded. RESULTS: Cancer detection rate on repeat biopsy was 15.4%, with approximately 60% detected on the first repeat biopsy, but approximately 10% not confirmed until the fourth repeat biopsy. Gleason score was similar regardless of the time of diagnosis (6.1-6.5). Mean interval between first biopsy and cancer diagnosis (range 18-55 months) depended on the number of repeat procedures. There was an association between the number of biopsy cores and cancer detection. CONCLUSIONS: This study supports the practice of increasing the number of cores taken on initial and first repeat biopsy to maximise prostate cancer detection and reduce the overall number of biopsies needed.

  20. A relevance vector machine technique for the automatic detection of clustered microcalcifications (Honorable Mention Poster Award)

    Science.gov (United States)

    Wei, Liyang; Yang, Yongyi; Nishikawa, Robert M.

    2005-04-01

    Microcalcification (MC) clusters in mammograms can be important early signs of breast cancer in women. Accurate detection of MC clusters is an important but challenging problem. In this paper, we propose the use of a recently developed machine learning technique -- relevance vector machine (RVM) -- for automatic detection of MCs in digitized mammograms. RVM is based on Bayesian estimation theory, and as a feature it can yield a decision function that depends on only a very small number of so-called relevance vectors. We formulate MC detection as a supervised-learning problem, and use RVM to classify if an MC object is present or not at each location in a mammogram image. MC clusters are then identified by grouping the detected MC objects. The proposed method is tested using a database of 141 clinical mammograms, and compared with a support vector machine (SVM) classifier which we developed previously. The detection performance is evaluated using the free-response receiver operating characteristic (FROC) curves. It is demonstrated that the RVM classifier matches closely with the SVM classifier in detection performance, and does so with a much sparser kernel representation than the SVM classifier. Consequently, the RVM classifier greatly reduces the computational complexity, making it more suitable for real-time processing of MC clusters in mammograms.

  1. Development of an incipient rotor crack detection method by acoustic emission techniques

    International Nuclear Information System (INIS)

    Le Reverend, D.; Massouri, M.H.

    1988-01-01

    The objective of the program presented is to develop a method of detection and monitoring of crack growth in machine rotor by application of acoustic emission techniques. This program is performed by R and D Division of Electricite de France, jointly with INSA de Lyon. The first task of the program is relative to the characterization of acoustic emission during a progressive tensile test performed on a NCT specimen. The second task of the program deals with the experimentation of acoustic emission techniques for the monitoring of a specimen during cycling bending tests. The last task of the program is relative to evaluation of application of acoustic emission techniques for a small rotor integrity monitoring during fatigue rotation tests [fr

  2. Technique Based on Image Pyramid and Bayes Rule for Noise Reduction in Unsupervised Change Detection

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-qiang; HUO hong; FANG Tao; ZHU Ju-lian; GE Wei-li

    2009-01-01

    In this paper, a technique based on image pyramid and Bayes rule for reducing noise effects in unsupervised change detection is proposed. By using Gaussian pyramid to process two multitemporal images respectively, two image pyramids are constructed. The difference pyramid images are obtained by point-by-point subtraction between the same level images of the two image pyramids. By resizing all difference pyramid images to the size of the original multitemporal image and then making product operator among them, a map being similar to the difference image is obtained. The difference image is generated by point-by-point subtraction between the two multitemporal images directly. At last, the Bayes rule is used to distinguish the changed pixels. Both synthetic and real data sets are used to evaluate the performance of the proposed technique. Experimental results show that the map from the proposed technique is more robust to noise than the difference image.

  3. Ultrasonic Phased Array Techniques for Detection of Flaws of Stud Bolts in Nuclear Power Plants

    International Nuclear Information System (INIS)

    Lee, Joon Hyun; Choi, Sang Woo

    2006-01-01

    The reactor vessel body and closure head are fastened with the stud bolt that is one of crucial parts for safety of the reactor vessels in nuclear power plants. It is reported that the stud bolt is often experienced by fatigue cracks initiated at threads. Stud bolts are inspected by the ultrasonic technique during the overhaul periodically for the prevention of failure which leads to radioactive leakage from the nuclear reactor. The conventional ultrasonic inspection for stud bolts was mainly conducted by reflected echo method based on shadow effect. However, in this technique, there were numerous spurious signals reflected from every oblique surfaces of the thread. In this study, ultrasonic phased array technique was applied to investigate detectability of flaws in stud bolts and characteristics of ultrasonic images corresponding to different scanning methods, that is, sector and linear scan. For this purpose, simplified stud bolt specimens with artificial defects of various depths were prepared

  4. A simple infrared-augmented digital photography technique for detection of pupillary abnormalities.

    Science.gov (United States)

    Shazly, Tarek A; Bonhomme, G R

    2015-03-01

    The purpose of the study was to describe a simple infrared photography technique to aid in the diagnosis and documentation of pupillary abnormalities. An unmodified 12-megapixel "point and shoot" digital camera was used to obtain binocular still photos and videos under different light conditions with near-infrared illuminating frames. The near-infrared light of 850 nm allows the capture of clear pupil images in both dim and bright light conditions. It also allows easy visualization of the pupil despite pigmented irides by augmenting the contrast between the iris and the pupil. The photos and videos obtained illustrated a variety of pupillary abnormalities using the aforementioned technique. This infrared-augmented photography technique supplements medical education, and aids in the more rapid detection, diagnosis, and documentation of a wide spectrum of pupillary abnormalities. Its portability and ease of use with minimal training complements the education of trainees and facilitates the establishment of difficult diagnoses.

  5. Atomic absorption spectrophotometry in perspective

    International Nuclear Information System (INIS)

    Soffiantini, V.

    1981-01-01

    Atomic absorption spectrophotometry is essentially an analytical technique used for quantitative trace metal analysis in a variety of materials. The speed and specificity of the technique is its greatest advantage over other analytical techniques. What atomic absorption spectrophotometry can and cannot do and its advantages and disadvantages are discussed, a summary of operating instructions are given, as well as a summary of analytical interferences. The applications of atomic absorption spectrophotometry are also shortly discussed

  6. Robust fault detection in bond graph framework using interval analysis and Fourier-Motzkin elimination technique

    Science.gov (United States)

    Jha, Mayank Shekhar; Chatti, Nizar; Declerck, Philippe

    2017-09-01

    This paper addresses the fault diagnosis problem of uncertain systems in the context of Bond Graph modelling technique. The main objective is to enhance the fault detection step based on Interval valued Analytical Redundancy Relations (named I-ARR) in order to overcome the problems related to false alarms, missed alarms and robustness issues. These I-ARRs are a set of fault indicators that generate the interval bounds called thresholds. A fault is detected once the nominal residuals (point valued part of I-ARRs) exceed the thresholds. However, the existing fault detection method is limited to parametric faults and it presents various limitations with regards to estimation of measurement signal derivatives, to which I-ARRs are sensitive. The novelties and scientific interest of the proposed methodology are: (1) to improve the accuracy of the measurements derivatives estimation by using a dedicated sliding mode differentiator proposed in this work, (2) to suitably integrate the Fourier-Motzkin Elimination (FME) technique within the I-ARRs based diagnosis so that measurements faults can be detected successfully. The latter provides interval bounds over the derivatives which are included in the thresholds. The proposed methodology is studied under various scenarios (parametric and measurement faults) via simulations over a mechatronic torsion bar system.

  7. Automatic detection of adverse events to predict drug label changes using text and data mining techniques.

    Science.gov (United States)

    Gurulingappa, Harsha; Toldo, Luca; Rajput, Abdul Mateen; Kors, Jan A; Taweel, Adel; Tayrouz, Yorki

    2013-11-01

    The aim of this study was to assess the impact of automatically detected adverse event signals from text and open-source data on the prediction of drug label changes. Open-source adverse effect data were collected from FAERS, Yellow Cards and SIDER databases. A shallow linguistic relation extraction system (JSRE) was applied for extraction of adverse effects from MEDLINE case reports. Statistical approach was applied on the extracted datasets for signal detection and subsequent prediction of label changes issued for 29 drugs by the UK Regulatory Authority in 2009. 76% of drug label changes were automatically predicted. Out of these, 6% of drug label changes were detected only by text mining. JSRE enabled precise identification of four adverse drug events from MEDLINE that were undetectable otherwise. Changes in drug labels can be predicted automatically using data and text mining techniques. Text mining technology is mature and well-placed to support the pharmacovigilance tasks. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Intrusion detection techniques for plant-wide network in a nuclear power plant

    International Nuclear Information System (INIS)

    Rajasekhar, P.; Shrikhande, S.V.; Biswas, B.B.; Patil, R.K.

    2012-01-01

    Nuclear power plants have a lot of critical data to be sent to the operator workstations. A plant wide integrated communication network, with high throughput, determinism and redundancy, is required between the workstations and the field. Switched Ethernet network is a promising prospect for such an integrated communication network. But for such an integrated system, intrusion is a major issue. Hence the network should have an intrusion detection system to make the network data secure and enhance the network availability. Intrusion detection is the process of monitoring the events occurring in a network and analyzing them for signs of possible incidents, which are violations or imminent threats of violation of network security policies, acceptable user policies, or standard security practices. This paper states the various intrusion detection techniques and approaches which are applicable for analysis of a plant wide network. (author)

  9. Development of neutron interrogation techniques for detection of hazardous substances in containers port

    International Nuclear Information System (INIS)

    D’Amico, N. M. B; Mayer, R.E; Tartaglione, A.

    2013-01-01

    This work is aimed at contributing to the effort of nations seeking to control international borders movement of dangerous chemical substances and nuclear material, in accordance with a multitude of agreements signed to that purpose. At this stage, we try to identify the signature of pure substances: chlorine (Cl), nitrogen (N), chromium (Cr), mercury (Hg), cadmium (Cd), uranium (U) y arsenic (As) and, later, to detect their presence in simulated large cargo containers. The technique employed in previous and in current work, consists in the detection of prompt and early decay gammas induced by incident thermal neutrons or fast neutrons thermalized in the cargo array. Uranium has also been detected through the counting of fast neutrons originated in induced fissions. (author)

  10. Inability to detect significant absorption of immunoreactive soya protein in healthy adults may be relevant to its weak allergenicity

    DEFF Research Database (Denmark)

    Lund, Cecilia M; Dirks, Christina G; Pedersen, Mona H

    2013-01-01

    ABSTRACT: Soya and peanut are botanically closely related and share cross-reacting antigens, but compared to soya, peanut allergy has a higher prevalence with more severe allergic reactions. Furthermore, the threshold dose for eliciting reactions is higher for soya. A difference in undigested...... of soya protein. While we cannot totally exlude technical reasons, it may also reflect a true poor absorption in healthy adult volunteers. This could, in turn, be relevant to the apparently weak allergenicity of soy protein by comparison with peanut protein in allergic subjects....

  11. Intersubband absorption in annealed InAs/GaAs quantum dots: a case for polarization-sensitive infrared detection

    International Nuclear Information System (INIS)

    Chakrabarti, S; Bhattacharya, P; Stiff-Roberts, A D; Lin, Y Y; Singh, J; Lei, Y; Browning, N

    2003-01-01

    We have studied the characteristics of intersubband absorption of polarized infrared (IR) radiation in as-grown and annealed self-organized InAs/GaAs quantum dots. It is observed that with the increase of annealing time and temperature, the dots tend to flatten and behave more like quantum wells. As a result, their sensitivity to TE (in-plane)-polarized light decreases and that to TM (out-of-plane)-polarized light increases. The effect could be utilized for the realization of polarization-sensitive IR detectors

  12. Detection of breast cancer using advanced techniques of data mining with neural networks

    International Nuclear Information System (INIS)

    Ortiz M, J. A.; Celaya P, J. M.; Martinez B, M. R.; Solis S, L. O.; Castaneda M, R.; Garza V, I.; Martinez F, M.; Lopez H, Y.; Ortiz R, J. M.

    2016-10-01

    The breast cancer is one of the biggest health problems worldwide, is the most diagnosed cancer in women and prevention seems impossible since its cause is unknown, due to this; the early detection has a key role in the patient prognosis. In developing countries such as Mexico, where access to specialized health services is minimal, the regular clinical review is infrequent and there are not enough radiologists; the most common form of detection of breast cancer is through self-exploration, but this is only detected in later stages, when is already palpable. For these reasons, the objective of the present work is the creation of a system of computer assisted diagnosis (CAD x) using information analysis techniques such as data mining and advanced techniques of artificial intelligence, seeking to offer a previous medical diagnosis or a second opinion, as if it was a second radiologist in order to reduce the rate of mortality from breast cancer. In this paper, advances in the design of computational algorithms using computer vision techniques for the extraction of features derived from mammograms are presented. Using data mining techniques of data mining is possible to identify patients with a high risk of breast cancer. With the information obtained from the mammography analysis, the objective in the next stage will be to establish a methodology for the generation of imaging bio-markers to establish a breast cancer risk index for Mexican patients. In this first stage we present results of the classification of patients with high and low risk of suffering from breast cancer using neural networks. (Author)

  13. Validation of a new technique to detect Cryptosporidium spp. oocysts in bovine feces.

    Science.gov (United States)

    Inácio, Sandra Valéria; Gomes, Jancarlo Ferreira; Oliveira, Bruno César Miranda; Falcão, Alexandre Xavier; Suzuki, Celso Tetsuo Nagase; Dos Santos, Bianca Martins; de Aquino, Monally Conceição Costa; de Paula Ribeiro, Rafaela Silva; de Assunção, Danilla Mendes; Casemiro, Pamella Almeida Freire; Meireles, Marcelo Vasconcelos; Bresciani, Katia Denise Saraiva

    2016-11-01

    Due to its important zoonotic potential, cryptosporidiosis arouses strong interest in the scientific community, because, it was initially considered a rare and opportunistic disease. The parasitological diagnosis of the causative agent of this disease, the protozoan Cryptosporidium spp., requires the use of specific techniques of concentration and permanent staining, which are laborious and costly, and are difficult to use in routine laboratory tests. In view of the above, we conducted the feasibility, development, evaluation and intralaboratory validation of a new parasitological technique for analysis in optical microscopy of Cryptosporidium spp. oocysts, called TF-Test Coccidia, using fecal samples from calves from the city of Araçatuba, São Paulo. To confirm the aforementioned parasite and prove the diagnostic efficiency of the new technique, we used two established methodologies in the scientific literature: parasite concentration by centrifugal sedimentation and negative staining with malachite green (CSN-Malachite) and Nested-PCR. We observed good effectiveness of the TF-Test Coccidia technique, being statistically equivalent to CSN-Malachite. Thus, we verified the effectiveness of the TF-Test Coccidia parasitological technique for the detection of Cryptosporidium spp. oocysts and observed good concentration and morphology of the parasite, with a low amount of debris in the fecal smear. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Bronchial intubation could be detected by the visual stethoscope techniques in pediatric patients.

    Science.gov (United States)

    Kimura, Tetsuro; Suzuki, Akira; Mimuro, Soichiro; Makino, Hiroshi; Sato, Shigehito

    2012-12-01

    We created a system that allows the visualization of breath sounds (visual stethoscope). We compared the visual stethoscope technique with auscultation for the detection of bronchial intubation in pediatric patients. In the auscultation group, an anesthesiologist advanced the tracheal tube, while another anesthesiologist auscultated bilateral breath sounds to detect the change and/or disappearance of unilateral breath sounds. In the visualization group, the stethoscope was used to detect changes in breath sounds and/or disappearance of unilateral breath sounds. The distance from the edge of the mouth to the carina was measured using a fiberoptic bronchoscope. Forty pediatric patients were enrolled in the study. At the point at which irregular breath sounds were auscultated, the tracheal tube was located at 0.5 ± 0.8 cm on the bronchial side from the carina. When a detectable change of shape of the visualized breath sound was observed, the tracheal tube was located 0.1 ± 1.2 cm on the bronchial side (not significant). At the point at which unilateral breath sounds were auscultated or a unilateral shape of the visualized breath sound was observed, the tracheal tube was 1.5 ± 0.8 or 1.2 ± 1.0 cm on the bronchial side, respectively (not significant). The visual stethoscope allowed to display the left and the right lung sound simultaneously and detected changes of breath sounds and unilateral breath sound as a tracheal tube was advanced. © 2012 Blackwell Publishing Ltd.

  15. STEM - software test and evaluation methods: fault detection using static analysis techniques

    International Nuclear Information System (INIS)

    Bishop, P.G.; Esp, D.G.

    1988-08-01

    STEM is a software reliability project with the objective of evaluating a number of fault detection and fault estimation methods which can be applied to high integrity software. This Report gives some interim results of applying both manual and computer-based static analysis techniques, in particular SPADE, to an early CERL version of the PODS software containing known faults. The main results of this study are that: The scope for thorough verification is determined by the quality of the design documentation; documentation defects become especially apparent when verification is attempted. For well-defined software, the thoroughness of SPADE-assisted verification for detecting a large class of faults was successfully demonstrated. For imprecisely-defined software (not recommended for high-integrity systems) the use of tools such as SPADE is difficult and inappropriate. Analysis and verification tools are helpful, through their reliability and thoroughness. However, they are designed to assist, not replace, a human in validating software. Manual inspection can still reveal errors (such as errors in specification and errors of transcription of systems constants) which current tools cannot detect. There is a need for tools to automatically detect typographical errors in system constants, for example by reporting outliers to patterns. To obtain the maximum benefit from advanced tools, they should be applied during software development (when verification problems can be detected and corrected) rather than retrospectively. (author)

  16. Detection of adrenocortical autoantibodies in Addison's disease with a peroxidase-labelled protein A technique

    Directory of Open Access Journals (Sweden)

    R.C. Silva

    1998-09-01

    Full Text Available Adrenocortical autoantibodies (ACA, present in 60-80% of patients with idiopathic Addison's disease, are conventionally detected by indirect immunofluorescence (IIF on frozen sections of adrenal glands. The large-scale use of IIF is limited in part by the need for a fluorescence microscope and the fact that histological sections cannot be stored for long periods of time. To circumvent these restrictions we developed a novel peroxidase-labelled protein A (PLPA technique for the detection of ACA in patients with Addison's disease and compared the results with those obtained with the classical IIF assay. We studied serum samples from 90 healthy control subjects and 22 patients with Addison's disease, who had been clinically classified into two groups: idiopathic (N = 13 and granulomatous (N = 9. ACA-PLPA were detected in 10/22 (45% patients: 9/13 (69% with the idiopathic form and 1/9 (11% with the granulomatous form, whereas ACA-IIF were detected in 11/22 patients (50%: 10/13 (77% with the idiopathic form and 1/9 (11% with the granulomatous form. Twelve of the 13 idiopathic addisonians (92% were positive for either ACA-PLPA or ACA-IIF, but only 7 were positive by both methods. In contrast, none of 90 healthy subjects was found to be positive for ACA. Thus, our study shows that the PLPA-based technique is useful, has technical advantages over the IIF method (by not requiring the use of a fluorescence microscope and by permitting section storage for long periods of time. However, since it is only 60% concordant with the ACA-IIF method, it should be considered complementary instead of an alternative method to IIF for the detection of ACA in human sera.

  17. Evaluation of Advanced Signal Processing Techniques to Improve Detection and Identification of Embedded Defects

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, Dwight A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Santos-Villalobos, Hector J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baba, Justin S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    , or an improvement in contrast over conventional SAFT reconstructed images. This report documents our efforts in four fronts: 1) Comparative study between traditional SAFT and FBD SAFT for concrete specimen with and without Alkali-Silica Reaction (ASR) damage, 2) improvement of our Model-Based Iterative Reconstruction (MBIR) for thick reinforced concrete [5], 3) development of a universal framework for sharing, reconstruction, and visualization of ultrasound NDE datasets, and 4) application of machine learning techniques for automated detection of ASR inside concrete. Our comparative study between FBD and traditional SAFT reconstruction images shows a clear difference between images of ASR and non-ASR specimens. In particular, the left first harmonic shows an increased contrast and sensitivity to ASR damage. For MBIR, we show the superiority of model-based techniques over delay and sum techniques such as SAFT. Improvements include elimination of artifacts caused by direct arrival signals, and increased contrast and Signal to Noise Ratio. For the universal framework, we document a format for data storage based on the HDF5 file format, and also propose a modular Graphic User Interface (GUI) for easy customization of data conversion, reconstruction, and visualization routines. Finally, two techniques for ASR automated detection are presented. The first technique is based on an analysis of the frequency content using Hilbert Transform Indicator (HTI) and the second technique employees Artificial Neural Network (ANN) techniques for training and classification of ultrasound data as ASR or non-ASR damaged classes. The ANN technique shows great potential with classification accuracy above 95%. These approaches are extensible to the detection of additional reinforced, thick concrete defects and damage.

  18. Coupling continuous ultrasound-assisted extraction, preconcentration and flame atomic absorption spectrometric detection for the determination of cadmium and lead in mussel samples

    International Nuclear Information System (INIS)

    Yebra-Biurrun, M.C.; Cancela-Perez, S.; Moreno-Cid-Barinaga, A.

    2005-01-01

    Continuous ultrasound-assisted extraction has been coupled with preconcentration and flame atomic absorption spectrometry for the determination of cadmium and lead in mussel samples. Experimental designs were used for the optimisation of the leaching and preconcentration steps. The use of diluted nitric acid as extractant in the continuous mode at a flow rate of 3.5 ml min -1 and room temperature was sufficient for quantitative extraction of these trace metals. A minicolumn containing a chelating resin (Chelite P, with aminomethylphosphoric acid groups) was proved as an excellent material for the quantitative preconcentration of cadmium and lead prior to their flame atomic absorption detection. A flow injection manifold was used as interface for coupling the three analytical steps, which allowed the automation of the whole analytical process. A good precision of the whole procedure (2.0 and 2.3%), high enrichment factors (20.5 and 11.8) and a detection limit of 0.011 and 0.25 μg g -1 for cadmium and lead, respectively, were obtained for 80 mg of sample. The sample throughputs were ca. 16 and 14 samples h -1 for cadmium and lead, respectively. The accuracy of the analytical procedures was verified by using a standard reference material (BCR 278-R, mussel tissue) and the results were in good agreement with the certified values. The method was successfully applied to the determination of trace amounts of cadmium and lead in mussel samples from the coast of Galicia (NW, Spain)

  19. Detection of cow's milk proteins and minor components in human milk using proteomics techniques.

    Science.gov (United States)

    Coscia, A; Orrù, S; Di Nicola, P; Giuliani, F; Varalda, A; Peila, C; Fabris, C; Conti, A; Bertino, E

    2012-10-01

    Cow's milk proteins (CMPs) are the best characterized food allergens. The aim of this study was to investigate cow's milk allergens in human colostrum of term and preterm newborns' mothers, and other minor protein components by proteomics techniques, more sensitive than other techniques used in the past. Sixty-two term and 11 preterm colostrum samples were collected, subjected to a treatment able to increase the concentration of the most diluted proteins and simultaneously to reduce the concentration of the proteins present at high concentration (Proteominer Treatment), and subsequently subjected to the steps of proteomic techniques. The most relevant finding in this study was the detection of the intact bovine alpha-S1-casein in human colostrum, then bovine alpha-1-casein could be considered the cow's milk allergen that is readily secreted in human milk and could be a cause of sensitization to cow's milk in exclusively breastfed predisposed infants. Another interesting result was the detection, at very low concentrations, of proteins previously not described in human milk (galectin-7, the different isoforms of the 14-3-3 protein and the serum amyloid P-component), probably involved in the regulation of the normal cell growth, in the pro-apoptotic function and in the regulation of tissue homeostasis. Further investigations are needed to understand if these families of proteins have specific biological activity in human milk.

  20. Biological, serological and molecular techniques to xanthomonas axonopodis pv. Ci tri Asymptomatic detection

    International Nuclear Information System (INIS)

    Peyrou, M.; Del Campo, R.; Russi, P.; Mara, H.; Rigamonti, N.; Larrechart, L.; Perez, E.

    2012-01-01

    Xanthomonas axonopodis pv. ci tri (X ac) produces citrus canker disease in all citrus commercial species. The bacteria can be disseminated through vegetative propagation material in asymptomatic form. To optimize bacteria detection techniques applicable to asymptomatic citrus plant tissue routine analysis, ELISA, Immunofluorescence, Pcr, qRT P CR and host plant inoculation (bioassay) diagnostic techniques were compared. Tests were made from decimal dilutions between 108 uf6.ml-1 and 102 ufc.mL-1 using a pure culture of 49b strain.The detection level obtained was 1.8 x 102 ufc.mL-1 using Inmunofluorescence; 1.8x104 ufc.mL-1 with indirect ELISA, 1.8 x 103 ufc.mL-1 by means of PCR; 10 ufc.mL-1 through of qRT P CR and 230 ufc.mL-1 in sour orange inoculated plants. The experiment was repeated at least three times for each technique. Considering this result, and taking into account that sensitivity, practicity and cost, are important when a great number of plants need to be tested, the PCR and inoculation in host plants were those that met the best characteristics to be evaluated in asymptomatic plant material