Two phase sampling

CERN Document Server

Ahmad, Zahoor; Hanif, Muhammad

2013-01-01

The development of estimators of population parameters based on two-phase sampling schemes has seen a dramatic increase in the past decade. Various authors have developed estimators of population using either one or two auxiliary variables. The present volume is a comprehensive collection of estimators available in single and two phase sampling. The book covers estimators which utilize information on single, two and multiple auxiliary variables of both quantitative and qualitative nature. Th...

Review of online coupling of sample preparation techniques with liquid chromatography.

Science.gov (United States)

Pan, Jialiang; Zhang, Chengjiang; Zhang, Zhuomin; Li, Gongke

2014-03-07

Sample preparation is still considered as the bottleneck of the whole analytical procedure, and efforts has been conducted towards the automation, improvement of sensitivity and accuracy, and low comsuption of organic solvents. Development of online sample preparation techniques (SP) coupled with liquid chromatography (LC) is a promising way to achieve these goals, which has attracted great attention. This article reviews the recent advances on the online SP-LC techniques. Various online SP techniques have been described and summarized, including solid-phase-based extraction, liquid-phase-based extraction assisted with membrane, microwave assisted extraction, ultrasonic assisted extraction, accelerated solvent extraction and supercritical fluids extraction. Specially, the coupling approaches of online SP-LC systems and the corresponding interfaces have been discussed and reviewed in detail, such as online injector, autosampler combined with transport unit, desorption chamber and column switching. Typical applications of the online SP-LC techniques have been summarized. Then the problems and expected trends in this field are attempted to be discussed and proposed in order to encourage the further development of online SP-LC techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of the Sampling Selection Technique in Approaching Financial Audit

Directory of Open Access Journals (Sweden)

Victor Munteanu

2018-03-01

Full Text Available In his professional approach, the financial auditor has a wide range of working techniques, including selection techniques. They are applied depending on the nature of the information available to the financial auditor, the manner in which they are presented - paper or electronic format, and, last but not least, the time available. Several techniques are applied, successively or in parallel, to increase the safety of the expressed opinion and to provide the audit report with a solid basis of information. Sampling is used in the phase of control or clarification of the identified error. The main purpose is to corroborate or measure the degree of risk detected following a pertinent analysis. Since the auditor does not have time or means to thoroughly rebuild the information, the sampling technique can provide an effective response to the need for valorization.

Aliasless fresnel transform image reconstruction in phase scrambling fourier transform technique by data interpolation

International Nuclear Information System (INIS)

Yamada, Yoshifumi; Liu, Na; Ito, Satoshi

2006-01-01

The signal in the Fresnel transform technique corresponds to a blurred one of the spin density image. Because the amplitudes of adjacent sampled signals have a high interrelation, the signal amplitude at a point between sampled points can be estimated with a high degree of accuracy even if the sampling is so coarse as to generate aliasing in the reconstructed images. In this report, we describe a new aliasless image reconstruction technique in the phase scrambling Fourier transform (PSFT) imaging technique in which the PSFT signals are converted to Fresnel transform signals by multiplying them by a quadratic phase term and are then interpolated using polynomial expressions to generate fully encoded signals. Numerical simulation using MR images showed that almost completely aliasless images are reconstructed by this technique. Experiments using ultra-low-field PSFT MRI were conducted, and aliasless images were reconstructed from coarsely sampled PSFT signals. (author)

Recent Trends in Microextraction Techniques Employed in Analytical and Bioanalytical Sample Preparation

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Abuzar Kabir

2017-12-01

Full Text Available Sample preparation has been recognized as a major step in the chemical analysis workflow. As such, substantial efforts have been made in recent years to simplify the overall sample preparation process. Major focusses of these efforts have included miniaturization of the extraction device; minimizing/eliminating toxic and hazardous organic solvent consumption; eliminating sample pre-treatment and post-treatment steps; reducing the sample volume requirement; reducing extraction equilibrium time, maximizing extraction efficiency etc. All these improved attributes are congruent with the Green Analytical Chemistry (GAC principles. Classical sample preparation techniques such as solid phase extraction (SPE and liquid-liquid extraction (LLE are being rapidly replaced with emerging miniaturized and environmentally friendly techniques such as Solid Phase Micro Extraction (SPME, Stir bar Sorptive Extraction (SBSE, Micro Extraction by Packed Sorbent (MEPS, Fabric Phase Sorptive Extraction (FPSE, and Dispersive Liquid-Liquid Micro Extraction (DLLME. In addition to the development of many new generic extraction sorbents in recent years, a large number of molecularly imprinted polymers (MIPs created using different template molecules have also enriched the large cache of microextraction sorbents. Application of nanoparticles as high-performance extraction sorbents has undoubtedly elevated the extraction efficiency and method sensitivity of modern chromatographic analyses to a new level. Combining magnetic nanoparticles with many microextraction sorbents has opened up new possibilities to extract target analytes from sample matrices containing high volumes of matrix interferents. The aim of the current review is to critically audit the progress of microextraction techniques in recent years, which has indisputably transformed the analytical chemistry practices, from biological and therapeutic drug monitoring to the environmental field; from foods to phyto

New applications using phased array techniques

International Nuclear Information System (INIS)

Erhard, A.; Schenk, G.; Hauser, Th.; Voelz, U.

2001-01-01

In general, the application of phased array techniques used to be limited to heavy components with large wall thicknesses, such as those in the nuclear power industry. With the improvement of the phased array equipment, including phased array search units, other application areas are now accessible for the phased array inspection technique, e.g. the inspection of turbine blade roots, weld inspection with a wall thickness ranging from 12 to 40 mm, inspection of aircraft components, inspection of spot welds and the inspection of concrete building components. The objective for the use of phased array techniques has not significantly changed since their first application, e.g. instant adjustment of the sound beam to the geometry of the test object by steering incidence angle, skew angle and/or sound field focusing. Because some new phased array technique applications are still in the experimental (laboratory) stage, this article will focus on some examples for practical, real-weld applications

Experimental and theoretical contributions to X-ray phase-contrast techniques for medical imaging

International Nuclear Information System (INIS)

Diemoz, P.C.

2011-01-01

Several X-ray phase-contrast techniques have recently been developed. Unlike conventional X-ray methods, which measure the absorption properties of the tissues, these techniques derive contrast also from the modulation of the phase produced by the sample. Since the phase shift can be significant even for small details characterized by weak or absent absorption, the achievable image contrast can be greatly increased, notably for the soft biological tissues. These methods are therefore very promising for applications in the medical domain. The aim of this work is to contribute to a deeper understanding of these techniques, in particular propagation-based imaging (PBI), analyzer-based imaging (ABI) and grating interferometry (GIFM), and to study their potential and the best practical implementation for medical imaging applications. An important part of this work is dedicated to the use of mathematical algorithms for the extraction, from the acquired images, of quantitative sample information (the absorption, refraction and scattering sample properties). In particular, five among the most known algorithms based on the geometrical optics approximation have been theoretically analysed and experimentally compared, in planar and tomographic modalities, by using geometrical phantoms and human bone-cartilage and breast samples. A semi-quantitative method for the acquisition and reconstruction of tomographic images in the ABI and GIFM techniques has also been proposed. The validity conditions are analyzed in detail and the method, enabling a considerable simplification of the imaging procedure, has been experimentally checked on phantoms and human samples. Finally, a theoretical and experimental comparison of the PBI, ABI and GIFM techniques is presented. The advantages and drawbacks of each of these techniques are discussed. The results obtained from this analysis can be very useful for determining the most adapted technique for a given application. (author)

Experimental and theoretical contributions to X-ray phase-contrast techniques for medical imaging; Contributions experimentales et theoriques aux techniques de contraste de phase pour l'imagerie medicale par rayons X

Energy Technology Data Exchange (ETDEWEB)

Diemoz, P.C.

2011-02-28

Several X-ray phase-contrast techniques have recently been developed. Unlike conventional X-ray methods, which measure the absorption properties of the tissues, these techniques derive contrast also from the modulation of the phase produced by the sample. Since the phase shift can be significant even for small details characterized by weak or absent absorption, the achievable image contrast can be greatly increased, notably for the soft biological tissues. These methods are therefore very promising for applications in the medical domain. The aim of this work is to contribute to a deeper understanding of these techniques, in particular propagation-based imaging (PBI), analyzer-based imaging (ABI) and grating interferometry (GIFM), and to study their potential and the best practical implementation for medical imaging applications. An important part of this work is dedicated to the use of mathematical algorithms for the extraction, from the acquired images, of quantitative sample information (the absorption, refraction and scattering sample properties). In particular, five among the most known algorithms based on the geometrical optics approximation have been theoretically analysed and experimentally compared, in planar and tomographic modalities, by using geometrical phantoms and human bone-cartilage and breast samples. A semi-quantitative method for the acquisition and reconstruction of tomographic images in the ABI and GIFM techniques has also been proposed. The validity conditions are analyzed in detail and the method, enabling a considerable simplification of the imaging procedure, has been experimentally checked on phantoms and human samples. Finally, a theoretical and experimental comparison of the PBI, ABI and GIFM techniques is presented. The advantages and drawbacks of each of these techniques are discussed. The results obtained from this analysis can be very useful for determining the most adapted technique for a given application. (author)

The use of Moessbauer technique in the identification of iron phases in blood

International Nuclear Information System (INIS)

A-lArabi, Ibtisam Abdusalam

2008-03-01

In this work we used marabou's technique, x-diffraction techniques, and thermal analysis to identify iron phases in a number of different samples such as: prescription medicine used as iron supplement, a blood sample from a healthy person, a blood sample from a person with thalassemia, and a sample from the plant (Jirjeer). In spite of the diminishing amount of iron in all of these samples we were able to identify the phases of iron and their proportions. There were an agreement between the results of x-ray diffraction and Moessbauer on the presence of the compound (FeSO 4 .H 2 O) in the first sample. We calculated the average particle size of this sample to be 0.2 μm. The Moessbauer results of the second sample indicated the presence of two iron phases. One with parameters (ΔΕ Q =1.376 mm/s, δ=-0.17 mm/s) was assigned to oxygenated hemoglobin. The second with parameters (ΔΕ Q =1.371 mm/s, δ=0.41 mm/s) was assigned to non-oxygenated hemoglobin. In the results of the third sample there was no indication of the presence of ferric iron which is the form in which excess iron is stored in the red blood cells of thalassaemic blood. The results of the fourth sample indicated that iron is present in the plant sample in two different sites in the iron-sulfur protein molecule. thermal analysis results helped in determining the temperatures at which there was phase transformation of iron compounds molecule. thermal analysis results helped in determining the temperatures at which there was phase transformation of iron compounds. (author)

Determination of palladium in biological samples applying nuclear analytical techniques

International Nuclear Information System (INIS)

Cavalcante, Cassio Q.; Sato, Ivone M.; Salvador, Vera L. R.; Saiki, Mitiko

2008-01-01

This study presents Pd determinations in bovine tissue samples containing palladium prepared in the laboratory, and CCQM-P63 automotive catalyst materials of the Proficiency Test, using instrumental thermal and epithermal neutron activation analysis and energy dispersive X-ray fluorescence techniques. Solvent extraction and solid phase extraction procedures were also applied to separate Pd from interfering elements before the irradiation in the nuclear reactor. The results obtained by different techniques were compared against each other to examine sensitivity, precision and accuracy. (author)

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)

Two sampling techniques for game meat

OpenAIRE

van der Merwe, Maretha; Jooste, Piet J.; Hoffman, Louw C.; Calitz, Frikkie J.

2013-01-01

A study was conducted to compare the excision sampling technique used by the export market and the sampling technique preferred by European countries, namely the biotrace cattle and swine test. The measuring unit for the excision sampling was grams (g) and square centimetres (cm2) for the swabbing technique. The two techniques were compared after a pilot test was conducted on spiked approved beef carcasses (n = 12) that statistically proved the two measuring units correlated. The two sampling...

Two sampling techniques for game meat

Directory of Open Access Journals (Sweden)

Maretha van der Merwe

2013-03-01

Full Text Available A study was conducted to compare the excision sampling technique used by the export market and the sampling technique preferred by European countries, namely the biotrace cattle and swine test. The measuring unit for the excision sampling was grams (g and square centimetres (cm2 for the swabbing technique. The two techniques were compared after a pilot test was conducted on spiked approved beef carcasses (n = 12 that statistically proved the two measuring units correlated. The two sampling techniques were conducted on the same game carcasses (n = 13 and analyses performed for aerobic plate count (APC, Escherichia coli and Staphylococcus aureus, for both techniques. A more representative result was obtained by swabbing and no damage was caused to the carcass. Conversely, the excision technique yielded fewer organisms and caused minor damage to the carcass. The recovery ratio from the sampling technique improved 5.4 times for APC, 108.0 times for E. coli and 3.4 times for S. aureus over the results obtained from the excision technique. It was concluded that the sampling methods of excision and swabbing can be used to obtain bacterial profiles from both export and local carcasses and could be used to indicate whether game carcasses intended for the local market are possibly on par with game carcasses intended for the export market and therefore safe for human consumption.

Two sampling techniques for game meat.

Science.gov (United States)

van der Merwe, Maretha; Jooste, Piet J; Hoffman, Louw C; Calitz, Frikkie J

2013-03-20

A study was conducted to compare the excision sampling technique used by the export market and the sampling technique preferred by European countries, namely the biotrace cattle and swine test. The measuring unit for the excision sampling was grams (g) and square centimetres (cm2) for the swabbing technique. The two techniques were compared after a pilot test was conducted on spiked approved beef carcasses (n = 12) that statistically proved the two measuring units correlated. The two sampling techniques were conducted on the same game carcasses (n = 13) and analyses performed for aerobic plate count (APC), Escherichia coli and Staphylococcus aureus, for both techniques. A more representative result was obtained by swabbing and no damage was caused to the carcass. Conversely, the excision technique yielded fewer organisms and caused minor damage to the carcass. The recovery ratio from the sampling technique improved 5.4 times for APC, 108.0 times for E. coli and 3.4 times for S. aureus over the results obtained from the excision technique. It was concluded that the sampling methods of excision and swabbing can be used to obtain bacterial profiles from both export and local carcasses and could be used to indicate whether game carcasses intended for the local market are possibly on par with game carcasses intended for the export market and therefore safe for human consumption.

Estimation of the sugar cane cultivated area from LANDSAT images using the two phase sampling method

Science.gov (United States)

Parada, N. D. J. (Principal Investigator); Cappelletti, C. A.; Mendonca, F. J.; Lee, D. C. L.; Shimabukuro, Y. E.

1982-01-01

A two phase sampling method and the optimal sampling segment dimensions for the estimation of sugar cane cultivated area were developed. This technique employs visual interpretations of LANDSAT images and panchromatic aerial photographs considered as the ground truth. The estimates, as a mean value of 100 simulated samples, represent 99.3% of the true value with a CV of approximately 1%; the relative efficiency of the two phase design was 157% when compared with a one phase aerial photographs sample.

Applications of the phased array technique

International Nuclear Information System (INIS)

Erhard, A.; Schenk, G.; Hauser, Th.; Voelz, U.

1999-01-01

The application of the phased array technique was limited to heavy and thick wall components as present in the nuclear industry. With the improvement of the equipment and probes other application areas are now open for the phased array technique, e.g. the inspection of the turbine blade root, weld inspection in a wall thickness range between 12 and 40 mm, inspection of aircraft components, inspection of spot welds or inspection of concretes. The aim of the use of phased array techniques has not been changed related to the first applications, i.e. the adaptation of the sound beam to the geometry by steering the angel of incidence or the skewing angle as well as the focussing of sound fields. Due to the fact, that the new applications of the phased array techniques in some cases don't leave the laboratories for the time being, the examples of this contribution will focus applications with practical background. (orig.)

Review of sample preparation techniques for the analysis of pesticide residues in soil.

Science.gov (United States)

Tadeo, José L; Pérez, Rosa Ana; Albero, Beatriz; García-Valcárcel, Ana I; Sánchez-Brunete, Consuelo

2012-01-01

This paper reviews the sample preparation techniques used for the analysis of pesticides in soil. The present status and recent advances made during the last 5 years in these methods are discussed. The analysis of pesticide residues in soil requires the extraction of analytes from this matrix, followed by a cleanup procedure, when necessary, prior to their instrumental determination. The optimization of sample preparation is a very important part of the method development that can reduce the analysis time, the amount of solvent, and the size of samples. This review considers all aspects of sample preparation, including extraction and cleanup. Classical extraction techniques, such as shaking, Soxhlet, and ultrasonic-assisted extraction, and modern techniques like pressurized liquid extraction, microwave-assisted extraction, solid-phase microextraction and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) are reviewed. The different cleanup strategies applied for the purification of soil extracts are also discussed. In addition, the application of these techniques to environmental studies is considered.

Water sampling techniques for continuous monitoring of pesticides in water

Directory of Open Access Journals (Sweden)

Šunjka Dragana

2017-01-01

Full Text Available Good ecological and chemical status of water represents the most important aim of the Water Framework Directive 2000/60/EC, which implies respect of water quality standards at the level of entire river basin (2008/105/EC and 2013/39/EC. This especially refers to the control of pesticide residues in surface waters. In order to achieve the set goals, a continuous monitoring program that should provide a comprehensive and interrelated overview of water status should be implemented. However, it demands the use of appropriate analysis techniques. Until now, the procedure for sampling and quantification of residual pesticide quantities in aquatic environment was based on the use of traditional sampling techniques that imply periodical collecting of individual samples. However, this type of sampling provides only a snapshot of the situation in regard to the presence of pollutants in water. As an alternative, the technique of passive sampling of pollutants in water, including pesticides has been introduced. Different samplers are available for pesticide sampling in surface water, depending on compounds. The technique itself is based on keeping a device in water over a longer period of time which varies from several days to several weeks, depending on the kind of compound. In this manner, the average concentrations of pollutants dissolved in water during a time period (time-weighted average concentrations, TWA are obtained, which enables monitoring of trends in areal and seasonal variations. The use of these techniques also leads to an increase in sensitivity of analytical methods, considering that pre-concentration of analytes takes place within the sorption medium. However, the use of these techniques for determination of pesticide concentrations in real water environments requires calibration studies for the estimation of sampling rates (Rs. Rs is a volume of water per time, calculated as the product of overall mass transfer coefficient and area of

Simulating and assessing boson sampling experiments with phase-space representations

Science.gov (United States)

Opanchuk, Bogdan; Rosales-Zárate, Laura; Reid, Margaret D.; Drummond, Peter D.

2018-04-01

The search for new, application-specific quantum computers designed to outperform any classical computer is driven by the ending of Moore's law and the quantum advantages potentially obtainable. Photonic networks are promising examples, with experimental demonstrations and potential for obtaining a quantum computer to solve problems believed classically impossible. This introduces a challenge: how does one design or understand such photonic networks? One must be able to calculate observables using general methods capable of treating arbitrary inputs, dissipation, and noise. We develop complex phase-space software for simulating these photonic networks, and apply this to boson sampling experiments. Our techniques give sampling errors orders of magnitude lower than experimental correlation measurements for the same number of samples. We show that these techniques remove systematic errors in previous algorithms for estimating correlations, with large improvements in errors in some cases. In addition, we obtain a scalable channel-combination strategy for assessment of boson sampling devices.

Phase equilibria basic principles, applications, experimental techniques

CERN Document Server

Reisman, Arnold

2013-01-01

Phase Equilibria: Basic Principles, Applications, Experimental Techniques presents an analytical treatment in the study of the theories and principles of phase equilibria. The book is organized to afford a deep and thorough understanding of such subjects as the method of species model systems; condensed phase-vapor phase equilibria and vapor transport reactions; zone refining techniques; and nonstoichiometry. Physicists, physical chemists, engineers, and materials scientists will find the book a good reference material.

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.

Radioisotope Sample Measurement Techniques in Medicine and Biology. Proceedings of the Symposium on Radioisotope Sample Measurement Techniques

International Nuclear Information System (INIS)

1965-01-01

The medical and biological applications of radioisotopes depend on two basically different types of measurements, those on living subjects in vivo and those on samples in vitro. The International Atomic Energy Agency has in the past held several meetings on in vivo measurement techniques, notably whole-body counting and radioisotope scanning. The present volume contains the Proceedings of the first Symposium the Agency has organized to discuss the various aspects of techniques for sample measurement in vitro. The range of these sample measurement techniques is very wide. The sample may weigh a few milligrams or several hundred grams, and may be in the gaseous, liquid or solid state. Its radioactive content may consist of a single, known radioisotope or several unknown ones. The concentration of radioactivity may be low, medium or high. The measurements may be made manually or automatically and any one of the many radiation detectors now available may be used. The 53 papers presented at the Symposium illustrate the great variety of methods now in use for radioactive- sample measurements. The first topic discussed is gamma-ray spectrometry, which finds an increasing number of applications in sample measurements. Other sections of the Proceedings deal with: the use of computers in gamma-ray spectrometry and multiple tracer techniques; recent developments in activation analysis where both gamma-ray spectrometry and computing techniques are applied; thin-layer and paper radio chromatographic techniques for use with low energy beta-ray emitters; various aspects of liquid scintillation counting techniques in the measurement of alpha- and beta-ray emitters, including chemical and colour quenching; autoradiographic techniques; calibration of equipment; and standardization of radioisotopes. Finally, some applications of solid-state detectors are presented; this section may be regarded as a preview of important future developments. The meeting was attended by 203 participants

Non-Conventional Techniques for the Study of Phase Transitions in NiTi-Based Alloys

Science.gov (United States)

Nespoli, Adelaide; Villa, Elena; Passaretti, Francesca; Albertini, Franca; Cabassi, Riccardo; Pasquale, Massimo; Sasso, Carlo Paolo; Coïsson, Marco

2014-07-01

Differential scanning calorimetry and electrical resistance measurements are the two most common techniques for the study of the phase transition path and temperatures of shape memory alloys (SMA) in stress-free condition. Besides, it is well known that internal friction measurements are also useful for this purpose. There are indeed some further techniques which are seldom used for the basic characterization of SMA transition: dilatometric analysis, magnetic measurements, and Seebeck coefficient study. In this work, we discuss the attitude of these techniques for the study of NiTi-based phase transition. Measurements were conducted on several fully annealed Ni50- x Ti50Cu x samples ranging from 3 to 10 at.% in Cu content, fully annealed at 850 °C for 1 h in vacuum and quenched in water at room temperature. Results show that all these techniques are sensitive to phase transition, and they provide significant information about the existence of intermediate phases.

Solid phase microextraction headspace sampling of chemical warfare agent contaminated samples : method development for GC-MS analysis

Energy Technology Data Exchange (ETDEWEB)

Jackson Lepage, C.R.; Hancock, J.R. [Defence Research and Development Canada, Medicine Hat, AB (Canada); Wyatt, H.D.M. [Regina Univ., SK (Canada)

2004-07-01

Defence R and D Canada-Suffield (DRDC-Suffield) is responsible for analyzing samples that are suspected to contain chemical warfare agents, either collected by the Canadian Forces or by first-responders in the event of a terrorist attack in Canada. The analytical techniques used to identify the composition of the samples include gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy. GC-MS and LC-MS generally require solvent extraction and reconcentration, thereby increasing sample handling. The authors examined analytical techniques which reduce or eliminate sample manipulation. In particular, this paper presented a screening method based on solid phase microextraction (SPME) headspace sampling and GC-MS analysis for chemical warfare agents such as mustard, sarin, soman, and cyclohexyl methylphosphonofluoridate in contaminated soil samples. SPME is a method which uses small adsorbent polymer coated silica fibers that trap vaporous or liquid analytes for GC or LC analysis. Collection efficiency can be increased by adjusting sampling time and temperature. This method was tested on two real-world samples, one from excavated chemical munitions and the second from a caustic decontamination mixture. 7 refs., 2 tabs., 3 figs.

Phase Velocity Estimation of a Microstrip Line in a Stoichiometric Periodically Domain-Inverted LiTaO3 Modulator Using Electro-Optic Sampling Technique

Directory of Open Access Journals (Sweden)

Shintaro Hisatake

2008-01-01

Full Text Available We estimate the phase velocity of a modulation microwave in a quasi-velocity-matched (QVM electro-optic (EO phase modulator (QVM-EOM using EO sampling which is accurate and the most reliable technique for measuring voltage waveforms at an electrode. The substrate of the measured QVM-EOM is a stoichiometric periodically domain-inverted LiTaO3 crystal. The electric field of a standing wave in a resonant microstrip line (width: 0.5 mm, height: 0.5 mm is measured by employing a CdTe crystal as an EO sensor. The wavelength of the traveling microwave at 16.0801 GHz is determined as 3.33 mm by fitting the theoretical curve to the measured electric field distribution. The phase velocity is estimated as vm=5.35×107 m/s, though there exists about 5% systematic error due to the perturbation by the EO sensor. Relative dielectric constant of εr=41.5 is led as the maximum likelihood value that derives the estimated phase velocity.

Advances phase-lock techniques

CERN Document Server

Crawford, James A

2008-01-01

From cellphones to micrprocessors, to GPS navigation, phase-lock techniques are utilized in most all modern electronic devices. This high-level book takes a systems-level perspective, rather than circuit-level, which differentiates it from other books in the field.

Solving mercury (Hg) speciation in soil samples by synchrotron X-ray microspectroscopic techniques.

Science.gov (United States)

Terzano, Roberto; Santoro, Anna; Spagnuolo, Matteo; Vekemans, Bart; Medici, Luca; Janssens, Koen; Göttlicher, Jörg; Denecke, Melissa A; Mangold, Stefan; Ruggiero, Pacifico

2010-08-01

Direct mercury (Hg) speciation was assessed for soil samples with a Hg concentration ranging from 7 up to 240 mg kg(-1). Hg chemical forms were identified and quantified by sequential extractions and bulk- and micro-analytical techniques exploiting synchrotron generated X-rays. In particular, microspectroscopic techniques such as mu-XRF, mu-XRD and mu-XANES were necessary to solve bulk Hg speciation, in both soil fractions soil samples were metacinnabar (beta-HgS), cinnabar (alpha-HgS), corderoite (Hg(3)S(2)Cl(2)), and an amorphous phase containing Hg bound to chlorine and sulfur. The amount of metacinnabar and amorphous phases increased in the fraction soil components was observed. All the observed Hg-species originated from the slow weathering of an inert Hg-containing waste material (K106, U.S. EPA) dumped in the area several years ago, which is changing into a relatively more dangerous source of pollution. Copyright 2010 Elsevier Ltd. All rights reserved.

Critical evaluation of sample pretreatment techniques.

Science.gov (United States)

Hyötyläinen, Tuulia

2009-06-01

Sample preparation before chromatographic separation is the most time-consuming and error-prone part of the analytical procedure. Therefore, selecting and optimizing an appropriate sample preparation scheme is a key factor in the final success of the analysis, and the judicious choice of an appropriate procedure greatly influences the reliability and accuracy of a given analysis. The main objective of this review is to critically evaluate the applicability, disadvantages, and advantages of various sample preparation techniques. Particular emphasis is placed on extraction techniques suitable for both liquid and solid samples.

Sample Exchange Evaluation (SEE) Report - Phase II

Energy Technology Data Exchange (ETDEWEB)

Winters, W.I.

1994-09-28

This report describes the results from Phase II of the Sample Exchange Evaluation (SEE) Program, a joint effort to compare analytical laboratory performance on samples from the Hanford Site`s high-level waste tanks. In Phase II, the program has been expanded to include inorganic constituents in addition to radionuclides. Results from Phase II that exceeded 20% relative percent difference criteria are identified.

Sample Exchange Evaluation (SEE) Report - Phase II

International Nuclear Information System (INIS)

Winters, W.I.

1994-01-01

This report describes the results from Phase II of the Sample Exchange Evaluation (SEE) Program, a joint effort to compare analytical laboratory performance on samples from the Hanford Site's high-level waste tanks. In Phase II, the program has been expanded to include inorganic constituents in addition to radionuclides. Results from Phase II that exceeded 20% relative percent difference criteria are identified

Newly introduced sample preparation techniques: towards miniaturization.

Science.gov (United States)

Costa, Rosaria

2014-01-01

Sampling and sample preparation are of crucial importance in an analytical procedure, representing quite often a source of errors. The technique chosen for the isolation of analytes greatly affects the success of a chemical determination. On the other hand, growing concerns about environmental and human safety, along with the introduction of international regulations for quality control, have moved the interest of scientists towards specific needs. Newly introduced sample preparation techniques are challenged to meet new criteria: (i) miniaturization, (ii) higher sensitivity and selectivity, and (iii) automation. In this survey, the most recent techniques introduced in the field of sample preparation will be described and discussed, along with many examples of applications.

Coal ash fusion temperatures -- New characterization techniques, and associations with phase equilibria

Energy Technology Data Exchange (ETDEWEB)

Wall, T.F.; Gupta, R.P.; Gupta, S. [Univ. of Newcastle, New South Wales (Australia). Dept. of Chemical Engineering; Creelman, R.A. [R.A. Creelman and Associates, Epping, New South Wales (Australia); Coin, C. [ACIRL Ipswich, Booval, Queensland (Australia); Lowe, A. [Pacific Power, Sydney, New South Wales (Australia)

1996-12-31

The well-documented shortcomings of the standard technique for estimating the fusion temperature of coal ash are its subjective nature and poor accuracy. Alternative measurements based on the shrinkage and electrical conductivity of heating samples are therefore examined with laboratory ash prepared at about 800 C in crucibles, as well as combustion ash sampled from power stations. Sensitive shrinkage measurements indicate temperatures of rapid change which correspond to the formation of liquid phases that can be identified on ternary phase diagrams. The existence and extent of formation of these phases, as quantified by the magnitude of peaks in the test, provide alternative ash fusion temperatures. The peaks from laboratory ashes and corresponding combustion ashes derived from the same coals show clear differences which may be related to the evaporation of potassium during combustion and the reactions of the mineral residues to form combustion ash.

SHOT PUT O’BRIAN TECHNIQUE, EXTENDING THE ANALYSIS OF TECHNIQUE FROM FOUR TO SIX PHASES WITH THE DESCRIPTION

Directory of Open Access Journals (Sweden)

Zlatan Saračević

2011-09-01

Full Text Available Due to the complexity of the motion, shot put technique is described in phases for easier analysis, easer learning of technique and error correction. It is complete so that in its implementation the transition from phase to phase is not noticed. In aforementioned and described phases of O'Brian spinal shot put technique a large distance, emptiness and disconnection appear between the initial position phase and a phase of overtaking the device, which in the training methods and training technique in primary and secondary education, as well as for students and athletes beginners in shot put represents a major problem regarding connecting, training and technique advancement. Therefore, this work is aimed at facilitating the methods of training of shot put technique, extending from four to six phases, which have been described and include the complete O'Brian technique.

Intercomparison of techniques for inspection and diagnostics of heavy water reactor pressure tubes: Flaw detection and characterization [Phase 1] [Sample summary reports of pressure tube samples from Argentina, India, Canada, Republic of Korea, and Romania

International Nuclear Information System (INIS)

2006-05-01

Nuclear power plants with heavy water reactors (HWRs) comprise nine percent of today's operating nuclear units, and more are under construction. Efficient and accurate inspection and diagnostic techniques for various reactor components and systems are an important factor in assuring reliable and safe plant operation. To foster international collaboration in the efficient and safe use of nuclear power, the IAEA conducted a Coordinated Research Programme (CRP) on Inter-comparison of Techniques for HWR Pressure Tube Inspection and Diagnostics. This CRP was carried out within the frame of the IAEA Department of Nuclear Energy's Technical Working Group on Advanced Technologies for HWRs (the TWG-HWR). The TWG-HWR is a group of experts nominated by their governments and designated by the IAEA to provide advice and to support implementation of the IAEA's project on advanced technologies for HWRs. The objective of the CRP was to inter-compare non-destructive inspection and diagnostic techniques, in use and being developed, for structural integrity assessment of HWR pressure tubes. During the first phase of this CRP, participants have investigated the capability of different techniques to detect and characterize flaws. During the second phase of this CRP, participants collaborated to detect and characterize hydride blisters and to determine the hydrogen concentration in Zirconium alloys. The intent was to identify the most effective pressure tube inspection and diagnostic methods, and to identify further development needs. The organizations that have participated in this CRP are: - The Comision Nacional de Energia Atomica (CNEA), Argentina; - Atomic Energy of Canada Ltd. (AECL); Chalk River Laboratories (CRL), Canada; - The Research Institute of Nuclear Power Operations (RINPO), China National Nuclear Corporation (CNNC), China; - Bhabha Atomic Research Centre (BARC), India; - The Korea Electric Power Research Institute (KEPRI), Republic of Korea; - The Korea Atomic Energy

Recent Application of Solid Phase Based Techniques for Extraction and Preconcentration of Cyanotoxins in Environmental Matrices.

Science.gov (United States)

Mashile, Geaneth Pertunia; Nomngongo, Philiswa N

2017-03-04

Cyanotoxins are toxic and are found in eutrophic, municipal, and residential water supplies. For this reason, their occurrence in drinking water systems has become a global concern. Therefore, monitoring, control, risk assessment, and prevention of these contaminants in the environmental bodies are important subjects associated with public health. Thus, rapid, sensitive, selective, simple, and accurate analytical methods for the identification and determination of cyanotoxins are required. In this paper, the sampling methodologies and applications of solid phase-based sample preparation methods for the determination of cyanotoxins in environmental matrices are reviewed. The sample preparation techniques mainly include solid phase micro-extraction (SPME), solid phase extraction (SPE), and solid phase adsorption toxin tracking technology (SPATT). In addition, advantages and disadvantages and future prospects of these methods have been discussed.

Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

Energy Technology Data Exchange (ETDEWEB)

Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

2016-03-21

X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

Comparison of sampling techniques for use in SYVAC

International Nuclear Information System (INIS)

Dalrymple, G.J.

1984-01-01

The Stephen Howe review (reference TR-STH-1) recommended the use of a deterministic generator (DG) sampling technique for sampling the input values to the SYVAC (SYstems Variability Analysis Code) program. This technique was compared with Monte Carlo simple random sampling (MC) by taking a 1000 run case of SYVAC using MC as the reference case. The results show that DG appears relatively inaccurate for most values of consequence when used with 11 sample intervals. If 22 sample intervals are used then DG generates cumulative distribution functions that are statistically similar to the reference distribution. 400 runs of DG or MC are adequate to generate a representative cumulative distribution function. The MC technique appears to perform better than DG for the same number of runs. However, the DG predicts higher doses and in view of the importance of generating data in the high dose region this sampling technique with 22 sample intervals is recommended for use in SYVAC. (author)

Proteomic Challenges: Sample Preparation Techniques for Microgram-Quantity Protein Analysis from Biological Samples

Directory of Open Access Journals (Sweden)

Peter Feist

2015-02-01

Full Text Available Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed.

Proteomic Challenges: Sample Preparation Techniques for Microgram-Quantity Protein Analysis from Biological Samples

Science.gov (United States)

Feist, Peter; Hummon, Amanda B.

2015-01-01

Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower) and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed. PMID:25664860

Proteomic challenges: sample preparation techniques for microgram-quantity protein analysis from biological samples.

Science.gov (United States)

Feist, Peter; Hummon, Amanda B

2015-02-05

Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower) and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed.

NAIL SAMPLING TECHNIQUE AND ITS INTERPRETATION

Directory of Open Access Journals (Sweden)

TZAR MN

2011-01-01

Full Text Available The clinical suspicion of onychomyosis based on appearance of the nails, requires culture for confirmation. This is because treatment requires prolonged use of systemic agents which may cause side effects. One of the common problems encountered is improper nail sampling technique which results in loss of essential information. The unfamiliar terminologies used in reporting culture results may intimidate physicians resulting in misinterpretation and hamper treatment decision. This article provides a simple guide on nail sampling technique and the interpretation of culture results.

Development of sampling techniques for ITER Type B radwaste

International Nuclear Information System (INIS)

Hong, Kwon Pyo; Kim, Sung Geun; Jung, Sang Hee; Oh, Wan Ho; Park, Myung Chul; Kim, Hee Moon; Ahn, Sang Bok

2016-01-01

There are several difficulties and limitation in sampling activities. As the Type B radwaste components are mostly metallic(mostly stainless steel) and bulk(∼ 1 m in size and ∼ 100 mm in thickness), it is difficult in taking samples from the surface of Type B radwaste by remote operation. But also, sampling should be performed without use of any liquid coolant to avoid the spread of contamination. And all sampling procedures are carried in the hot cell red zone with remote operation. Three kinds of sampling techniques are being developed. They are core sampling, chip sampling, and wedge sampling, which are the candidates of sampling techniques to be applied to ITER hot cell. Object materials for sampling are stainless steel or Cu alloy block in order to simulate ITER Type B radwaste. The best sampling technique for ITER Type B radwaste among the three sampling techniques will be suggested in several months after finishing the related experiment

Development of sampling techniques for ITER Type B radwaste

Energy Technology Data Exchange (ETDEWEB)

Hong, Kwon Pyo; Kim, Sung Geun; Jung, Sang Hee; Oh, Wan Ho; Park, Myung Chul; Kim, Hee Moon; Ahn, Sang Bok [KAERI, Daejeon (Korea, Republic of)

2016-05-15

There are several difficulties and limitation in sampling activities. As the Type B radwaste components are mostly metallic(mostly stainless steel) and bulk(∼ 1 m in size and ∼ 100 mm in thickness), it is difficult in taking samples from the surface of Type B radwaste by remote operation. But also, sampling should be performed without use of any liquid coolant to avoid the spread of contamination. And all sampling procedures are carried in the hot cell red zone with remote operation. Three kinds of sampling techniques are being developed. They are core sampling, chip sampling, and wedge sampling, which are the candidates of sampling techniques to be applied to ITER hot cell. Object materials for sampling are stainless steel or Cu alloy block in order to simulate ITER Type B radwaste. The best sampling technique for ITER Type B radwaste among the three sampling techniques will be suggested in several months after finishing the related experiment.

Boat sampling technique for assessment of ageing of components

International Nuclear Information System (INIS)

Kumar, Kundan; Shyam, T.V.; Kayal, J.N.; Rupani, B.B.

2006-01-01

Boat sampling technique (BST) is a surface sampling technique, which has been developed for obtaining, in-situ, metal samples from the surface of an operating component without affecting its operating service life. The BST is non-destructive in nature and the sample is obtained without plastic deformation or without thermal degradation of the parent material. The shape and size of the sample depends upon the shape of the cutter and the surface geometry of the parent material. Miniature test specimens are generated from the sample and the specimens are subjected to various tests, viz. Metallurgical Evaluation, Metallographic Evaluation, Micro-hardness Evaluation, sensitisation test, small punch test etc. to confirm the integrity and assessment of safe operating life of the component. This paper highlights design objective of boat sampling technique, description of sampling module, sampling cutter and its performance evaluation, cutting process, boat samples, operational sequence of sampling module, qualification of sampling module, qualification of sampling technique, qualification of scooped region of the parent material, sample retrieval system, inspection, testing and examination to be carried out on the boat samples and scooped region. (author)

Observation on the stability of the solid phase microparticles separating technique in T3, T4 radioimmunoassay

International Nuclear Information System (INIS)

Chen Guangliang; Chen Xunmin

1995-01-01

The solid phase T 3 ,T 4 RIA is adopted at various laboratories. The data analysis from the effective dose and quality control of samples indicates that the separation technique is of good effect and high stability. It is an effective separation technique for the quality control in RIA

Urine sampling techniques in symptomatic primary-care patients

DEFF Research Database (Denmark)

Holm, Anne; Aabenhus, Rune

2016-01-01

in infection rate between mid-stream-clean-catch, mid-stream-urine and random samples. Conclusions: At present, no evidence suggests that sampling technique affects the accuracy of the microbiological diagnosis in non-pregnant women with symptoms of urinary tract infection in primary care. However......Background: Choice of urine sampling technique in urinary tract infection may impact diagnostic accuracy and thus lead to possible over- or undertreatment. Currently no evidencebased consensus exists regarding correct sampling technique of urine from women with symptoms of urinary tract infection...... a randomized or paired design to compare the result of urine culture obtained with two or more collection techniques in adult, female, non-pregnant patients with symptoms of urinary tract infection. We evaluated quality of the studies and compared accuracy based on dichotomized outcomes. Results: We included...

Microextraction Techniques Coupled to Liquid Chromatography with Mass Spectrometry for the Determination of Organic Micropollutants in Environmental Water Samples

Directory of Open Access Journals (Sweden)

Mª Esther Torres Padrón

2014-07-01

Full Text Available Until recently, sample preparation was carried out using traditional techniques, such as liquid–liquid extraction (LLE, that use large volumes of organic solvents. Solid-phase extraction (SPE uses much less solvent than LLE, although the volume can still be significant. These preparation methods are expensive, time-consuming and environmentally unfriendly. Recently, a great effort has been made to develop new analytical methodologies able to perform direct analyses using miniaturised equipment, thereby achieving high enrichment factors, minimising solvent consumption and reducing waste. These microextraction techniques improve the performance during sample preparation, particularly in complex water environmental samples, such as wastewaters, surface and ground waters, tap waters, sea and river waters. Liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS and time-of-flight mass spectrometric (TOF/MS techniques can be used when analysing a broad range of organic micropollutants. Before separating and detecting these compounds in environmental samples, the target analytes must be extracted and pre-concentrated to make them detectable. In this work, we review the most recent applications of microextraction preparation techniques in different water environmental matrices to determine organic micropollutants: solid-phase microextraction SPME, in-tube solid-phase microextraction (IT-SPME, stir bar sorptive extraction (SBSE and liquid-phase microextraction (LPME. Several groups of compounds are considered organic micropollutants because these are being released continuously into the environment. Many of these compounds are considered emerging contaminants. These analytes are generally compounds that are not covered by the existing regulations and are now detected more frequently in different environmental compartments. Pharmaceuticals, surfactants, personal care products and other chemicals are considered micropollutants. These

Non-terminal blood sampling techniques in guinea pigs.

Science.gov (United States)

Birck, Malene M; Tveden-Nyborg, Pernille; Lindblad, Maiken M; Lykkesfeldt, Jens

2014-10-11

Guinea pigs possess several biological similarities to humans and are validated experimental animal models(1-3). However, the use of guinea pigs currently represents a relatively narrow area of research and descriptive data on specific methodology is correspondingly scarce. The anatomical features of guinea pigs are slightly different from other rodent models, hence modulation of sampling techniques to accommodate for species-specific differences, e.g., compared to mice and rats, are necessary to obtain sufficient and high quality samples. As both long and short term in vivo studies often require repeated blood sampling the choice of technique should be well considered in order to reduce stress and discomfort in the animals but also to ensure survival as well as compliance with requirements of sample size and accessibility. Venous blood samples can be obtained at a number of sites in guinea pigs e.g., the saphenous and jugular veins, each technique containing both advantages and disadvantages(4,5). Here, we present four different blood sampling techniques for either conscious or anaesthetized guinea pigs. The procedures are all non-terminal procedures provided that sample volumes and number of samples do not exceed guidelines for blood collection in laboratory animals(6). All the described methods have been thoroughly tested and applied for repeated in vivo blood sampling in studies within our research facility.

Generation of complementary sampled phase-only holograms.

Science.gov (United States)

Tsang, P W M; Chow, Y T; Poon, T-C

2016-10-03

If an image is uniformly down-sampled into a sparse form and converted into a hologram, the phase component alone will be adequate to reconstruct the image. However, the appearance of the reconstructed image is degraded with numerous empty holes. In this paper, we present a low complexity and non-iterative solution to this problem. Briefly, two phase-only holograms are generated for an image, each based on a different down-sampling lattice. Subsequently, the holograms are displayed alternately at high frame rate. The reconstructed images of the 2 holograms will appear to be a single, densely sampled image with enhance visual quality.

Gas hydrate phase equilibria measurement techniques and phase rule considerations

International Nuclear Information System (INIS)

Beltran, Juan G.; Bruusgaard, Hallvard; Servio, Phillip

2012-01-01

Highlights: → Inconsistencies found in hydrate literature. → Clarification to the number of variables needed to satisfy and justify equilibrium data. → Application of phase rule to mixed hydrate systems. → Thermodynamically consistent format to present data. - Abstract: A brief review of the Gibbs phase rule for non-reacting systems and its correct application to clathrate hydrates is presented. Clarification is provided for a common mistake found in hydrate phase-equilibria literature, whereby initial compositions are used as intensive variables to satisfy the Gibbs phase rule instead of the equilibrium values. The system of (methane + carbon dioxide + water) under (hydrate + liquid + vapor) equilibrium is used as a case study to illustrate key points and suggestions to improve experimental techniques are proposed.

Hard x-ray phase contrastmicroscopy - techniques and applications

Science.gov (United States)

Holzner, Christian

In 1918, Einstein provided the first description of the nature of the refractive index for X-rays, showing that phase contrast effects are significant. A century later, most x-ray microscopy and nearly all medical imaging remains based on absorption contrast, even though phase contrast offers orders of magnitude improvements in contrast and reduced radiation exposure at multi-keV x-ray energies. The work presented is concerned with developing practical and quantitative methods of phase contrast for x-ray microscopy. A theoretical framework for imaging in phase contrast is put forward; this is used to obtain quantitative images in a scanning microscope using a segmented detector, and to correct for artifacts in a commercial phase contrast x-ray nano-tomography system. The principle of reciprocity between scanning and full-field microscopes is then used to arrive at a novel solution: Zernike contrast in a scanning microscope. These approaches are compared on a theoretical and experimental basis in direct connection with applications using multi-keV x-ray microscopes at the Advanced Photon Source at Argonne National Laboratory. Phase contrast provides the best means to image mass and ultrastructure of light elements that mainly constitute biological matter, while stimulated x-ray fluorescence provides high sensitivity for studies of the distribution of heavier trace elements, such as metals. These approaches are combined in a complementary way to yield quantitative maps of elemental concentration from 2D images, with elements placed in their ultrastructural context. The combination of x-ray fluorescence and phase contrast poses an ideal match for routine, high resolution tomographic imaging of biological samples in the future. The presented techniques and demonstration experiments will help pave the way for this development.

Sample preparation for large-scale bioanalytical studies based on liquid chromatographic techniques.

Science.gov (United States)

Medvedovici, Andrei; Bacalum, Elena; David, Victor

2018-01-01

Quality of the analytical data obtained for large-scale and long term bioanalytical studies based on liquid chromatography depends on a number of experimental factors including the choice of sample preparation method. This review discusses this tedious part of bioanalytical studies, applied to large-scale samples and using liquid chromatography coupled with different detector types as core analytical technique. The main sample preparation methods included in this paper are protein precipitation, liquid-liquid extraction, solid-phase extraction, derivatization and their versions. They are discussed by analytical performances, fields of applications, advantages and disadvantages. The cited literature covers mainly the analytical achievements during the last decade, although several previous papers became more valuable in time and they are included in this review. Copyright © 2017 John Wiley & Sons, Ltd.

Differences in sampling techniques on total post-mortem tryptase.

Science.gov (United States)

Tse, R; Garland, J; Kesha, K; Elstub, H; Cala, A D; Ahn, Y; Stables, S; Palmiere, C

2017-11-20

The measurement of mast cell tryptase is commonly used to support the diagnosis of anaphylaxis. In the post-mortem setting, the literature recommends sampling from peripheral blood sources (femoral blood) but does not specify the exact sampling technique. Sampling techniques vary between pathologists, and it is unclear whether different sampling techniques have any impact on post-mortem tryptase levels. The aim of this study is to compare the difference in femoral total post-mortem tryptase levels between two sampling techniques. A 6-month retrospective study comparing femoral total post-mortem tryptase levels between (1) aspirating femoral vessels with a needle and syringe prior to evisceration and (2) femoral vein cut down during evisceration. Twenty cases were identified, with three cases excluded from analysis. There was a statistically significant difference (paired t test, p sampling methods. The clinical significance of this finding and what factors may contribute to it are unclear. When requesting post-mortem tryptase, the pathologist should consider documenting the exact blood collection site and method used for collection. In addition, blood samples acquired by different techniques should not be mixed together and should be analyzed separately if possible.

Microextraction sample preparation techniques in biomedical analysis.

Science.gov (United States)

Szultka, Malgorzata; Pomastowski, Pawel; Railean-Plugaru, Viorica; Buszewski, Boguslaw

2014-11-01

Biologically active compounds are found in biological samples at relatively low concentration levels. The sample preparation of target compounds from biological, pharmaceutical, environmental, and food matrices is one of the most time-consuming steps in the analytical procedure. The microextraction techniques are dominant. Metabolomic studies also require application of proper analytical technique for the determination of endogenic metabolites present in biological matrix on trace concentration levels. Due to the reproducibility of data, precision, relatively low cost of the appropriate analysis, simplicity of the determination, and the possibility of direct combination of those techniques with other methods (combination types on-line and off-line), they have become the most widespread in routine determinations. Additionally, sample pretreatment procedures have to be more selective, cheap, quick, and environmentally friendly. This review summarizes the current achievements and applications of microextraction techniques. The main aim is to deal with the utilization of different types of sorbents for microextraction and emphasize the use of new synthesized sorbents as well as to bring together studies concerning the systematic approach to method development. This review is dedicated to the description of microextraction techniques and their application in biomedical analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sample preparation with solid phase microextraction and exhaustive extraction approaches: Comparison for challenging cases.

Science.gov (United States)

Boyacı, Ezel; Rodríguez-Lafuente, Ángel; Gorynski, Krzysztof; Mirnaghi, Fatemeh; Souza-Silva, Érica A; Hein, Dietmar; Pawliszyn, Janusz

2015-05-11

In chemical analysis, sample preparation is frequently considered the bottleneck of the entire analytical method. The success of the final method strongly depends on understanding the entire process of analysis of a particular type of analyte in a sample, namely: the physicochemical properties of the analytes (solubility, volatility, polarity etc.), the environmental conditions, and the matrix components of the sample. Various sample preparation strategies have been developed based on exhaustive or non-exhaustive extraction of analytes from matrices. Undoubtedly, amongst all sample preparation approaches, liquid extraction, including liquid-liquid (LLE) and solid phase extraction (SPE), are the most well-known, widely used, and commonly accepted methods by many international organizations and accredited laboratories. Both methods are well documented and there are many well defined procedures, which make them, at first sight, the methods of choice. However, many challenging tasks, such as complex matrix applications, on-site and in vivo applications, and determination of matrix-bound and free concentrations of analytes, are not easily attainable with these classical approaches for sample preparation. In the last two decades, the introduction of solid phase microextraction (SPME) has brought significant progress in the sample preparation area by facilitating on-site and in vivo applications, time weighted average (TWA) and instantaneous concentration determinations. Recently introduced matrix compatible coatings for SPME facilitate direct extraction from complex matrices and fill the gap in direct sampling from challenging matrices. Following introduction of SPME, numerous other microextraction approaches evolved to address limitations of the above mentioned techniques. There is not a single method that can be considered as a universal solution for sample preparation. This review aims to show the main advantages and limitations of the above mentioned sample

Large-volume constant-concentration sampling technique coupling with surface-enhanced Raman spectroscopy for rapid on-site gas analysis.

Science.gov (United States)

Zhang, Zhuomin; Zhan, Yisen; Huang, Yichun; Li, Gongke

2017-08-05

In this work, a portable large-volume constant-concentration (LVCC) sampling technique coupling with surface-enhanced Raman spectroscopy (SERS) was developed for the rapid on-site gas analysis based on suitable derivatization methods. LVCC sampling technique mainly consisted of a specially designed sampling cell including the rigid sample container and flexible sampling bag, and an absorption-derivatization module with a portable pump and a gas flowmeter. LVCC sampling technique allowed large, alterable and well-controlled sampling volume, which kept the concentration of gas target in headspace phase constant during the entire sampling process and made the sampling result more representative. Moreover, absorption and derivatization of gas target during LVCC sampling process were efficiently merged in one step using bromine-thiourea and OPA-NH 4 + strategy for ethylene and SO 2 respectively, which made LVCC sampling technique conveniently adapted to consequent SERS analysis. Finally, a new LVCC sampling-SERS method was developed and successfully applied for rapid analysis of trace ethylene and SO 2 from fruits. It was satisfied that trace ethylene and SO 2 from real fruit samples could be actually and accurately quantified by this method. The minor concentration fluctuations of ethylene and SO 2 during the entire LVCC sampling process were proved to be gas targets from real samples by SERS. Copyright © 2017 Elsevier B.V. All rights reserved.

Phase-Contrast Hounsfield Units of Fixated and Non-Fixated Soft-Tissue Samples

Science.gov (United States)

Willner, Marian; Fior, Gabriel; Marschner, Mathias; Birnbacher, Lorenz; Schock, Jonathan; Braun, Christian; Fingerle, Alexander A.; Noël, Peter B.; Rummeny, Ernst J.; Pfeiffer, Franz; Herzen, Julia

2015-01-01

X-ray phase-contrast imaging is a novel technology that achieves high soft-tissue contrast. Although its clinical impact is still under investigation, the technique may potentially improve clinical diagnostics. In conventional attenuation-based X-ray computed tomography, radiological diagnostics are quantified by Hounsfield units. Corresponding Hounsfield units for phase-contrast imaging have been recently introduced, enabling a setup-independent comparison and standardized interpretation of imaging results. Thus far, the experimental values of few tissue types have been reported; these values have been determined from fixated tissue samples. This study presents phase-contrast Hounsfield units for various types of non-fixated human soft tissues. A large variety of tissue specimens ranging from adipose, muscle and connective tissues to liver, kidney and pancreas tissues were imaged by a grating interferometer with a rotating-anode X-ray tube and a photon-counting detector. Furthermore, we investigated the effects of formalin fixation on the quantitative phase-contrast imaging results. PMID:26322638

Preliminary Studies Of A Phase Modulation Technique For Measuring Chromaticity

International Nuclear Information System (INIS)

Tan, C.-Y.

2006-01-01

The classical method for measuring chromaticity is to slowly modulate the RF frequency and then measure the betatron tune excursion. The technique that is discussed in this paper instead modulates the phase of the RF and then the chromaticity is obtained by phase demodulating the betatron tune. This technique requires knowledge of the betatron frequency in real time in order for the phase to be demodulated. Fortunately, the Tevatron has a tune tracker based on the phase locked loop principle which fits this requirement. A preliminary study with this technique has showed that it is a promising method for doing continuous chromaticity measurement and raises the possibility of doing successful chromaticity feedback with it

Large-volume constant-concentration sampling technique coupling with surface-enhanced Raman spectroscopy for rapid on-site gas analysis

Science.gov (United States)

Zhang, Zhuomin; Zhan, Yisen; Huang, Yichun; Li, Gongke

2017-08-01

In this work, a portable large-volume constant-concentration (LVCC) sampling technique coupling with surface-enhanced Raman spectroscopy (SERS) was developed for the rapid on-site gas analysis based on suitable derivatization methods. LVCC sampling technique mainly consisted of a specially designed sampling cell including the rigid sample container and flexible sampling bag, and an absorption-derivatization module with a portable pump and a gas flowmeter. LVCC sampling technique allowed large, alterable and well-controlled sampling volume, which kept the concentration of gas target in headspace phase constant during the entire sampling process and made the sampling result more representative. Moreover, absorption and derivatization of gas target during LVCC sampling process were efficiently merged in one step using bromine-thiourea and OPA-NH4+ strategy for ethylene and SO2 respectively, which made LVCC sampling technique conveniently adapted to consequent SERS analysis. Finally, a new LVCC sampling-SERS method was developed and successfully applied for rapid analysis of trace ethylene and SO2 from fruits. It was satisfied that trace ethylene and SO2 from real fruit samples could be actually and accurately quantified by this method. The minor concentration fluctuations of ethylene and SO2 during the entire LVCC sampling process were proved to be samples were achieved in range of 95.0-101% and 97.0-104% respectively. It is expected that portable LVCC sampling technique would pave the way for rapid on-site analysis of accurate concentrations of trace gas targets from real samples by SERS.

Sample exchange/evaluation (SEE) report - Phase III

International Nuclear Information System (INIS)

Winters, W.I.

1996-01-01

This report describes the results from Phase III of the Sample Exchange Evaluation (SEE) program. The SEE program is used to compare analytical laboratory performance on samples from the Hanford Site's high level waste tanks

Microstructural development of superconducting phases in Pb-BSCCO system derived from sol-gel technique

International Nuclear Information System (INIS)

Qureshi, A.H.; Hussain, N.; Durrani, S.K.; Waqas, H.; Arshad, M.

2010-01-01

Sol-gel processing technique has been utilized to produce the gel of Pb-BSCCO system (Bi/sub 2/-xPbxSr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/+-y, where x 0.2, 0.4, and 0.8, are the mole fraction of Pb substituted against Bi). The gel samples were subsequently heated to 800 deg. C for 2 h to obtain the powders which were then pressed and sintered at 845 deg. C for 60 h. The morphologies in the Pb-BSCCO gel, powder and sintered products were observed with scanning electron microscope (SEM) and optical microscope. The plate-like growths of the superconducting phases are evident from the SEM micrographs. The optical micrographs of sintered samples showed that the samples containing 0.2 and 0.8 mole fraction of Pb mainly consisted of dark grey and white regions, while sample having 0.4 mole fraction of Pb comprised of dark grey, light grey, and white regions. The different regions were analyzed by using energy dispersive X-rays (EDX) analyzer attached with SEM. The results revealed that the dark grey regions in all the samples represented the Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/ +- y (2212) phase whereas, light grey regions in sample (x = 0.4) constituted the Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ +- y (2223) phase. The white regions in all samples depicted the presence of CuO. The best result in term of larger fraction of superconducting phase (2223) has been observed in sample containing 0.4 mole fraction of Pb. (author)

Waste minimization in analytical chemistry through innovative sample preparation techniques

International Nuclear Information System (INIS)

Smith, L. L.

1998-01-01

water samples. In this SPME technique, a fused-silica fiber coated with a polymeric film is exposed to the sample, extraction is allowed to take place, and then the analytes are thermally desorbed for GC analysis. Unlike liquid-liquid extraction or solid-phase extraction, SPME consumes all of the extracted sample in the analysis, significantly reducing the required sample volume

Chromaticity tracking using a phase modulation technique

International Nuclear Information System (INIS)

Tan, C.Y.; Fermilab

2007-01-01

In the classical chromaticity measurement technique, chromaticity is measured by measuring the change in betatron tune as the RF frequency is varied. This paper will describe a novel way of measuring chromaticity: we will phase modulate the RF with a known sine wave and then phase demodulate the betatron frequency. The result is a line in Fourier space which corresponds to the frequency of our sine wave modulation. The peak of this sine wave is proportional to chromaticity. For this technique to work, a tune tracker PLL system is required because it supplies the betatron carrier frequency. This method has been tested in the Tevatron and we will show the results here

New materials for sample preparation techniques in bioanalysis.

Science.gov (United States)

Nazario, Carlos Eduardo Domingues; Fumes, Bruno Henrique; da Silva, Meire Ribeiro; Lanças, Fernando Mauro

2017-02-01

The analysis of biological samples is a complex and difficult task owing to two basic and complementary issues: the high complexity of most biological matrices and the need to determine minute quantities of active substances and contaminants in such complex sample. To succeed in this endeavor samples are usually subject to three steps of a comprehensive analytical methodological approach: sample preparation, analytes isolation (usually utilizing a chromatographic technique) and qualitative/quantitative analysis (usually with the aid of mass spectrometric tools). Owing to the complex nature of bio-samples, and the very low concentration of the target analytes to be determined, selective sample preparation techniques is mandatory in order to overcome the difficulties imposed by these two constraints. During the last decade new chemical synthesis approaches has been developed and optimized, such as sol-gel and molecularly imprinting technologies, allowing the preparation of novel materials for sample preparation including graphene and derivatives, magnetic materials, ionic liquids, molecularly imprinted polymers, and much more. In this contribution we will review these novel techniques and materials, as well as their application to the bioanalysis niche. Copyright © 2016 Elsevier B.V. All rights reserved.

Solving mercury (Hg) speciation in soil samples by synchrotron X-ray microspectroscopic techniques

International Nuclear Information System (INIS)

Terzano, Roberto; Santoro, Anna; Spagnuolo, Matteo; Vekemans, Bart; Medici, Luca; Janssens, Koen; Goettlicher, Joerg; Denecke, Melissa A.; Mangold, Stefan; Ruggiero, Pacifico

2010-01-01

Direct mercury (Hg) speciation was assessed for soil samples with a Hg concentration ranging from 7 up to 240 mg kg -1 . Hg chemical forms were identified and quantified by sequential extractions and bulk- and micro-analytical techniques exploiting synchrotron generated X-rays. In particular, microspectroscopic techniques such as μ-XRF, μ-XRD and μ-XANES were necessary to solve bulk Hg speciation, in both soil fractions 3 S 2 Cl 2 ), and an amorphous phase containing Hg bound to chlorine and sulfur. The amount of metacinnabar and amorphous phases increased in the fraction <2 μm. No interaction among Hg-species and soil components was observed. All the observed Hg-species originated from the slow weathering of an inert Hg-containing waste material (K106, U.S. EPA) dumped in the area several years ago, which is changing into a relatively more dangerous source of pollution. - Direct mercury (Hg) speciation in chlor-alkali plant contaminated soils enabled the identification of potentially dangerous Hg-S/Cl amorphous species.

Phase-only optical encryption based on the zeroth-order phase-contrast technique

Science.gov (United States)

Pizolato, José Carlos; Neto, Luiz Gonçalves

2009-09-01

A phase-only encryption/decryption scheme with the readout based on the zeroth-order phase-contrast technique (ZOPCT), without the use of a phase-changing plate on the Fourier plane of an optical system based on the 4f optical correlator, is proposed. The encryption of a gray-level image is achieved by multiplying the phase distribution obtained directly from the gray-level image by a random phase distribution. The robustness of the encoding is assured by the nonlinearity intrinsic to the proposed phase-contrast method and the random phase distribution used in the encryption process. The experimental system has been implemented with liquid-crystal spatial modulators to generate phase-encrypted masks and a decrypting key. The advantage of this method is the easy scheme to recover the gray-level information from the decrypted phase-only mask applying the ZOPCT. An analysis of this decryption method was performed against brute force attacks.

105-N Basin sediment disposition phase-one sampling and analysis plan

International Nuclear Information System (INIS)

1997-01-01

The sampling and analysis plan (SAP) for Phase 1 of the 105-N Basin sediment disposition project defines the sampling and analytical activities that will be performed for the engineering assessment phase (phase 1) of the project. A separate SAP defines the sampling and analytical activities that will be performed for the characterization phase (Phase 2) of the 105-N sediment disposition project. The Phase-1 SAP is presented in the introduction (Section 1.0), in the field sampling plan (FSP) (Section 2.0), and in the quality assurance project plan (QAPjP) (Section 3.0). The FSP defines the sampling and analytical methodologies to be performed. The QAPjP provides information on the quality assurance/quality control (QA/QC) parameters related to the sampling and analytical methodologies. This SAP defines the strategy and the methods that will be used to sample and analyze the sediment on the floor of the 105-N Basin. The resulting data will be used to develop and evaluate engineering designs for collecting and removing sediment from the basin

Sample-averaged biexciton quantum yield measured by solution-phase photon correlation.

Science.gov (United States)

Beyler, Andrew P; Bischof, Thomas S; Cui, Jian; Coropceanu, Igor; Harris, Daniel K; Bawendi, Moungi G

2014-12-10

The brightness of nanoscale optical materials such as semiconductor nanocrystals is currently limited in high excitation flux applications by inefficient multiexciton fluorescence. We have devised a solution-phase photon correlation measurement that can conveniently and reliably measure the average biexciton-to-exciton quantum yield ratio of an entire sample without user selection bias. This technique can be used to investigate the multiexciton recombination dynamics of a broad scope of synthetically underdeveloped materials, including those with low exciton quantum yields and poor fluorescence stability. Here, we have applied this method to measure weak biexciton fluorescence in samples of visible-emitting InP/ZnS and InAs/ZnS core/shell nanocrystals, and to demonstrate that a rapid CdS shell growth procedure can markedly increase the biexciton fluorescence of CdSe nanocrystals.

Development of analytical techniques for water and environmental samples (2)

Energy Technology Data Exchange (ETDEWEB)

Eum, Chul Hun; Jeon, Chi Wan; Jung, Kang Sup; Song, Kyung Sun; Kim, Sang Yeon [Korea Institute of Geology Mining and Materials, Taejon (Korea)

1998-12-01

The purpose of this study is to develop new analytical methods with good detection limit for toxic inorganic and organic compounds. The analyses of CN, organic acids, particulate materials in environmental samples have been done using several methods such as Ion Chromatography, SPE, SPME, GC/MS, GC/FID, SPLITT (split-flow thin cell fractionation) during the second year of this project. Advantage and disadvantage of several distillation method (by KS, JIS, EPA) for CN analysis in wastewater were investigated. As the results, we proposed new distillation apparatus for CN analysis, which was proved to be simpler, faster and to get better recovery than conventional apparatus. And ion chromatograph/pulsed amperometric detector (IC/PAD) system instead of colorimetry for CN detection was setup to solve matrix interference. And SPE(solid phase extraction) and SPME (solid phase micro extraction) as liquid-solid extraction technique were applied to the analysis of phenols in wastewater. Optimum experimental conditions and factors influencing analytical results were determined. From these results, It could be concluded that C{sub 18} cartridge and polystyrene-divinylbenzene disk in SPE method, polyacrylate fiber in SPME were proper solid phase adsorbent for phenol. Optimum conditions to analyze phenol derivatives simultaneously were established. Also, Continuous SPLITT (Split-flow thin cell) Fractionation (CSF) is a new preparative separation technique that is useful for fractionation of particulate and macromolecular materials. CSF is carried out in a thin ribbon-like channel equipped with two splitters at both inlet and outlet of the channel. In this work, we set up a new CSF system, and tested using polystyrene latex standard particles. And then we fractionated particles contained in air and underground water based on their sedimentation coefficients using CSF. (author). 27 refs., 13 tabs., 31 figs.

A comparative study of sampling techniques for monitoring carcass contamination

NARCIS (Netherlands)

Snijders, J.M.A.; Janssen, M.H.W.; Gerats, G.E.; Corstiaensen, G.P.

1984-01-01

Four bacteriological sampling techniques i.e. the excision, double swab, agar contract and modified agar contact techniques were compared by sampling pig carcasses before and after chilling. As well as assessing the advantages and disadvantages of the techniques particular attention was paid to

Sample preparation for special PIE-techniques at ITU

International Nuclear Information System (INIS)

Toscano, E.H.; Manzel, R.

2002-01-01

Several sample preparation techniques were developed and installed in hot cells. The techniques were conceived to evaluate the performance of highly burnt fuel rods and include: (a) a device for the removal of the fuel, (b) a method for the preparation of the specimen ends for the welding of new end caps and for the careful cleaning of samples for Transmission Electron Microscopy and Glow Discharge Mass Spectroscopy, (c) a sample pressurisation device for long term creep tests, and (d) a diameter measuring device for creep or burst samples. Examples of the determination of the mechanical properties, the behaviour under transient conditions and for the assessment of the corrosion behaviour of high burnup cladding materials are presented. (author)

Sampling phase lock loop (PLL) with low power clock buffer

NARCIS (Netherlands)

Gao, X.; Bahai, A.; Bohsali, M.; Djabbari, A.; Klumperink, Eric A.M.; Nauta, Bram; Socci, G.

2013-01-01

A sampling phase locked loop (PLL) circuit includes a pull-up/down buffer configured to convert an oscillator reference clock into a square wave sampling control signal input to a sampling phase detector. The buffer circuit is configured to reduce power by controlling the switching of the pull-up

Two-phase flow measurements using a photochromic dye activation technique

International Nuclear Information System (INIS)

Kawaji, M.

1998-01-01

A novel flow visualization method called photochromic dye activation (PDA) technique has been used to investigate flow structures and mechanisms in various two-phase flow regimes. This non-intrusive flow visualization technique utilizes light activation of a photochromic dye material dissolved in a clear liquid and is a molecular tagging technique, requiring no seed particles. It has been used to yield both quantitative and qualitative flow data in the liquid phase in annular flow, slug flow and stratified-wavy flows. (author)

Magnesium nitride phase formation by means of ion beam implantation technique

International Nuclear Information System (INIS)

Hoeche, Daniel; Blawert, Carsten; Cavellier, Matthieu; Busardo, Denis; Gloriant, Thierry

2011-01-01

Nitrogen implantation technique (Hardion + ) has been applied in order to modify the surface properties of magnesium and Mg-based alloys (AM50, AZ31). Nitrogen ions with an energy of approximately 100 keV were used to form the Mg 3 N 2 phase leading to improved surface properties. The samples were investigated using various characterization methods. Mechanical properties have been tested by means of nanoindention, the electrochemical behavior was measured by potentiodynamic polarization and impedance spectroscopy, phase formation by using grazing incidence Xray diffraction, the chemical state was determined by means of Xray induced photoelectron spectroscopy (XPS) and depth profiling by using secondary ions mass spectroscopy (SIMS). Additionally, the results were compared to calculated depth profiles using SRIM2008. The correlation of the results shows the nitride formation behavior to a depth of about 600 nm.

Characterization of ultrashort laser pulses employing self-phase modulation dispersion-scan technique

Science.gov (United States)

Sharba, A. B.; Chekhlov, O.; Wyatt, A. S.; Pattathil, R.; Borghesi, M.; Sarri, G.

2018-03-01

We present a new phase characterization technique for ultrashort laser pulses that employs self-phase modulation (SPM) in the dispersion scan approach. The method can be implemented by recording a set of nonlinearly modulated spectra generated with a set of known chirp values. The unknown phase of the pulse is retrieved by linking the recorded spectra to the initial spectrum of the pulse via a phase function guessed by a function minimization iterative algorithm. This technique has many advantages over the dispersion scan techniques that use frequency conversion processes. Mainly, the use of SPM cancels out the phase and group velocity mismatch errors and dramatically widens the spectral acceptance of the nonlinear medium and the range of working wavelength. The robustness of the technique is demonstrated with smooth and complex phase retrievals using numerical examples. The method is shown to be not affected by the spatial distribution of the beam or the presence of nonlinear absorption process. In addition, we present an efficient method for phase representation based on a summation of a set of Gaussian functions. The independence of the functions from each other prevents phase coupling of any kind and facilitates a flexible phase representation.

Silica Modified with Polyaniline as a Potential Sorbent for Matrix Solid Phase Dispersion (MSPD) and Dispersive Solid Phase Extraction (d-SPE) of Plant Samples

Science.gov (United States)

Sowa, Ireneusz; Wójciak-Kosior, Magdalena; Strzemski, Maciej; Sawicki, Jan; Staniak, Michał; Dresler, Sławomir; Szwerc, Wojciech; Mołdoch, Jarosław; Latalski, Michał

2018-01-01

Polyaniline (PANI) is one of the best known conductive polymers with multiple applications. Recently, it was also used in separation techniques, mostly as a component of composites for solid-phase microextraction (SPME). In the present paper, sorbent obtained by in situ polymerization of aniline directly on silica gel particles (Si-PANI) was used for dispersive solid phase extraction (d-SPE) and matrix solid–phase extraction (MSPD). The efficiency of both techniques was evaluated with the use of high performance liquid chromatography with diode array detection (HPLC-DAD) quantitative analysis. The quality of the sorbent was verified by Raman spectroscopy and microscopy combined with automated procedure using computer image analysis. For extraction experiments, triterpenes were chosen as model compounds. The optimal conditions were as follows: protonated Si-PANI impregnated with water, 160/1 sorbent/analyte ratio, 3 min of extraction time, 4 min of desorption time and methanolic solution of ammonia for elution of analytes. The proposed procedure was successfully used for pretreatment of plant samples. PMID:29565297

Non-terminal blood sampling techniques in Guinea pigs

DEFF Research Database (Denmark)

Birck, Malene Muusfeldt; Tveden-Nyborg, Pernille; Lindblad, Maiken Marie

2014-01-01

Guinea pigs possess several biological similarities to humans and are validated experimental animal models(1-3). However, the use of guinea pigs currently represents a relatively narrow area of research and descriptive data on specific methodology is correspondingly scarce. The anatomical features...... of guinea pigs are slightly different from other rodent models, hence modulation of sampling techniques to accommodate for species-specific differences, e.g., compared to mice and rats, are necessary to obtain sufficient and high quality samples. As both long and short term in vivo studies often require...... repeated blood sampling the choice of technique should be well considered in order to reduce stress and discomfort in the animals but also to ensure survival as well as compliance with requirements of sample size and accessibility. Venous blood samples can be obtained at a number of sites in guinea pigs e...

Gas-phase sample introduction techniques for the determination of some non-metals by ICP-AES, MIP-AES AND ICP-MS

International Nuclear Information System (INIS)

Nakahara, Taketoshi

2003-01-01

Various gas-phase sample introduction methods in analytical atomic spectrometry have been documented for up to 30 elements, but only a few of these methods with less than one-third of the analytes exhibit adequate, competitive performance characteristics. Most attractive are the chemical systems based on (i) reactions in aqueous media, (ii) with fast kinetics of chemical vapor generation and easy stripping off of vapors from solution, (iii) reliable interference control, (iv) with high and reducible chemical yields of volatile products which are (v) readily atomized, excited or ionized in a plasma, so as to provide adequate sensitivity and low limits of detection (LOD). Some significant advantage of gas-phase sample introduction over the widely-used pneumatic nebulization of liquid (solution) samples are (1) high chemical yields and transport efficiency, (2) separation from troublesome matrices, (3) enrichment, (4) automation in flow injection and continuous flow mode, (5) good sample throughput rates, (6) competitive LODs and RSDs, (7) commercially available accessories, (8) economically affordable and (9) speciation potentialities. To the contrary, the major disadvantages and limitations are (1) complex, on line-chemistry involved, (2) specific sample pre-treatment required, (3) effect of oxidation and binding state of analyte, (4) chemical interferences, (5) foaming and aerosol formation, (6) numerous instrumental and chemical parameters for optimization, (7) applicability to a limited number of analytes, (8) limited linear ranges and (9) poor-multi-element capabilities.

Evaluation of Wet Chemical ICP-AES Elemental Analysis Methods using Simulated Hanford Waste Samples-Phase I Interim Report

International Nuclear Information System (INIS)

Coleman, Charles J.; Edwards, Thomas B.

2005-01-01

The wet chemistry digestion method development for providing process control elemental analyses of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Melter Feed Preparation Vessel (MFPV) samples is divided into two phases: Phase I consists of: (1) optimizing digestion methods as a precursor to elemental analyses by ICP-AES techniques; (2) selecting methods with the desired analytical reliability and speed to support the nine-hour or less turnaround time requirement of the WTP; and (3) providing baseline comparison to the laser ablation (LA) sample introduction technique for ICP-AES elemental analyses that is being developed at the Savannah River National Laboratory (SRNL). Phase II consists of: (1) Time-and-Motion study of the selected methods from Phase I with actual Hanford waste or waste simulants in shielded cell facilities to ensure that the methods can be performed remotely and maintain the desired characteristics; and (2) digestion of glass samples prepared from actual Hanford Waste tank sludge for providing comparative results to the LA Phase II study. Based on the Phase I testing discussed in this report, a tandem digestion approach consisting of sodium peroxide fusion digestions carried out in nickel crucibles and warm mixed-acid digestions carried out in plastic bottles has been selected for Time-and-Motion study in Phase II. SRNL experience with performing this analytical approach in laboratory hoods indicates that well-trained cell operator teams will be able to perform the tandem digestions in five hours or less. The selected approach will produce two sets of solutions for analysis by ICP-AES techniques. Four hours would then be allocated for performing the ICP-AES analyses and reporting results to meet the nine-hour or less turnaround time requirement. The tandem digestion approach will need to be performed in two separate shielded analytical cells by two separate cell operator teams in order to achieve the nine-hour or less turnaround

Monitoring of persistent organic pollutants in seawater of the Pearl River Estuary with rapid on-site active SPME sampling technique

International Nuclear Information System (INIS)

Huang, Siming; He, Shuming; Xu, Hao; Wu, Peiyan; Jiang, Ruifen; Zhu, Fang; Luan, Tiangang; Ouyang, Gangfeng

2015-01-01

An on-site active solid-phase microextraction (SPME) sampling technique coupled with gas chromatography-mass spectrometry (GC–MS) for sampling and monitoring 16 polycyclic aromatic hydrocarbons (PAHs) and 8 organochlorine pesticides (OCPs) in seawater was developed. Laboratory experiments demonstrated that the sampling-rate calibration method was practical and could be used for the quantification of on-site sampling. The proposed method was employed for field tests which covered large amounts of water samples in the Pearl River Estuary in rainy and dry seasons. The on-site SPME sampling method can avoid the contamination of sample, the losses of analytes during sample transportation, as well as the usage of solvent and time-consuming sample preparation process. Results indicated that the technique with the designed device can address the requirement of modern environment water analysis. In addition, the sources, bioaccumulation and potential risk to human of the PAHs and OCPs in seawater of the Pearl River Estuary were discussed. - Highlights: • SPME on-site active sampling technique was developed and validated. • The technique was employed for field tests in the Pearl River Estuary. • 16 PAHs and 8 OCPs in the seawater of Pearl River Estuary were monitored. • The potential risk of the PAHs and OCPs in Pearl River Estuary were discussed. - An on-site active SPME sampling technique was developed and successfully applied for sampling and monitoring 16 PAHs and 8 OCPs in the Pearl River Estuary

THE PHASE REACTOR INDUCTANCE SELECTION TECHNIQUE FOR POWER ACTIVE FILTER

Directory of Open Access Journals (Sweden)

D. V. Tugay

2016-12-01

Full Text Available Purpose. The goal is to develop technique of the phase inductance power reactors selection for parallel active filter based on the account both low-frequency and high-frequency components of the electromagnetic processes in a power circuit. Methodology. We have applied concepts of the electrical circuits theory, vector analysis, mathematical simulation in Matlab package. Results. We have developed a new technique of the phase reactors inductance selection for parallel power active filter. It allows us to obtain the smallest possible value of THD network current. Originality. We have increased accuracy of methods of the phase reactor inductance selection for power active filter. Practical value. The proposed technique can be used in the design and manufacture of the active power filter for real objects of energy supply.

Open-Phase Fault Tolerance Techniques of Five-Phase Dual-Rotor Permanent Magnet Synchronous Motor

Directory of Open Access Journals (Sweden)

Jing Zhao

2015-11-01

Full Text Available Multi-phase motors are gaining more attention due to the advantages of good fault tolerance capability and high power density, etc. By applying dual-rotor technology to multi-phase machines, a five-phase dual-rotor permanent magnet synchronous motor (DRPMSM is researched in this paper to further promote their torque density and fault tolerance capability. It has two rotors and two sets of stator windings, and it can adopt a series drive mode or parallel drive mode. The fault-tolerance capability of the five-phase DRPMSM is researched. All open circuit fault types and corresponding fault tolerance techniques in different drive modes are analyzed. A fault-tolerance control strategy of injecting currents containing a certain third harmonic component is proposed for five-phase DRPMSM to ensure performance after faults in the motor or drive circuit. For adjacent double-phase faults in the motor, based on where the additional degrees of freedom are used, two different fault-tolerance current calculation schemes are adopted and the torque results are compared. Decoupling of the inner motor and outer motor is investigated under fault-tolerant conditions in parallel drive mode. The finite element analysis (FMA results and co-simulation results based on Simulink-Simplorer-Maxwell verify the effectiveness of the techniques.

Application of digital sampling techniques to particle identification

International Nuclear Information System (INIS)

Bardelli, L.; Poggi, G.; Bini, M.; Carraresi, L.; Pasquali, G.; Taccetti, N.

2003-01-01

An application of digital sampling techniques is presented which can greatly simplify experiments involving sub-nanosecond time-mark determinations and energy measurements with nuclear detectors, used for Pulse Shape Analysis and Time of Flight measurements in heavy ion experiments. In this work a 100 M Sample/s, 12 bit analog to digital converter has been used: examples of this technique applied to Silicon and CsI(Tl) detectors in heavy-ions experiments involving particle identification via Pulse Shape analysis and Time of Flight measurements are presented. The system is suited for applications to large detector arrays and to different kinds of detectors. Some preliminary results regarding the simulation of current signals in Silicon detectors are also discussed. (authors)

Phase transition of TiO{sub 2} thin films detected by the pulsed laser photoacoustic technique

Energy Technology Data Exchange (ETDEWEB)

Perez-Pacheco, A.; Castaneda-Guzman, R.; Oliva Montes de Oca, C.; Esparza-Garcia, A. [Universidad Nacional Autonoma de Mexico, CCADET-UNAM, Laboratorio de Fotofisica y Peliculas Delgadas, Cd. Universitaria, A.P. 70-186, Mexico D.F. (Mexico); Perez Ruiz, S.J. [CCADET-UNAM, Acustica y Vibraciones, Mexico D.F. (Mexico)

2011-03-15

In this work, we present characterization of titanium oxide thin films by photoacoustic measurements to determine the ablation threshold and phase transitions from amorphous to crystalline states. The important advantages of this method are that it does not require amplification at the detection stage and that it is a non-destructive technique. The correlation analysis of the photoacoustic signals allows us to visualize the ablation threshold and the phase transitions with enhanced sensitivity. This correlation analysis clearly exhibits the changes in the thin-film morphology due to controlled variations of the fluence (energy/area) and the temperature of the surrounding medium. This is particularly important for those cases where the crystalline changes caused by temperature variations need to be monitored. The thin-film samples were prepared by the sputtering technique at room temperature in the amorphous state. The phase transformations were induced by controlled temperature scanning and then corroborated with Raman spectroscopy measurements. (orig.)

Simulation tools for industrial applications of phased array inspection techniques

International Nuclear Information System (INIS)

Mahaut, St.; Roy, O.; Chatillon, S.; Calmon, P.

2001-01-01

Ultrasonic phased arrays techniques have been developed at the French Atomic Energy Commission in order to improve defects characterization and adaptability to various inspection configuration (complex geometry specimen). Such transducers allow 'standard' techniques - adjustable beam-steering and focusing -, or more 'advanced' techniques - self-focusing on defects for instance -. To estimate the performances of those techniques, models have been developed, which allows to compute the ultrasonic field radiated by an arbitrary phased array transducer through any complex specimen, and to predict the ultrasonic response of various defects inspected with a known beam. Both modeling applications are gathered in the Civa software, dedicated to NDT expertise. The use of those complementary models allows to evaluate the ability of a phased array to steer and focus the ultrasonic beam, and therefore its relevancy to detect and characterize defects. These models are specifically developed to give accurate solutions to realistic inspection applications. This paper briefly describes the CIVA models, and presents some applications dedicated to the inspection of complex specimen containing various defects with a phased array used to steer and focus the beam. Defect detection and characterization performances are discussed for the various configurations. Some experimental validation of both models are also presented. (authors)

Two-phase flow measurement by pulsed neutron activation techniques

International Nuclear Information System (INIS)

Kehler, P.

1978-01-01

The Pulsed Neutron Activation (PNA) technique for measuring the mass flow velocity and the average density of two-phase mixtures is described. PNA equipment can be easily installed at different loops, and PNA techniques are non-intrusive and independent of flow regimes. These features of the PNA technique make it suitable for in-situ measurement of two-phase flows, and for calibration of more conventional two-phase flow measurement devices. Analytic relations governing the various PNA methods are derived. The equipment and procedures used in the first air-water flow measurement by PNA techniques are discussed, and recommendations are made for improvement of future tests. In the present test, the mass flow velocity was determined with an accuracy of 2 percent, and average densities were measured down to 0.08 g/cm 3 with an accuracy of 0.04 g/cm 3 . Both the accuracy of the mass flow velocity measurement and the lower limit of the density measurement are functions of the injected activity and of the total number of counts. By using a stronger neutron source and a larger number of detectors, the measurable density can be decreased by a factor of 12 to .007 g/cm 3 for 12.5 cm pipes, and to even lower ranges for larger pipes

Extraction mechanism of sulfamethoxazole in water samples using aqueous two-phase systems of poly(propylene glycol) and salt

Energy Technology Data Exchange (ETDEWEB)

Xie Xueqiao; Wang Yun; Han Juan [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Yan Yongsheng, E-mail: yys@ujs.edu.cn [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

2011-02-14

Based on the poly(propylene glycol){sub 400} (PPG{sub 400})-salt aqueous two-phase system (ATPS), a green, economical and effective sample pretreatment technique coupled with high performance liquid chromatography was proposed for the separation and determination of sulfamethoxazole (SMX). The extraction yield of SMX in PPG{sub 400}-salt ATPS is influenced by various factors, including the salt species, the amount of salt, pH, and the temperature. Under the optimum conditions, most of SMX was partitioning into the polymer-rich phase with the average extraction efficiency of 99.2%, which may be attributed to the hydrophobic interaction and salting-out effect. This extraction technique has been successfully applied to the analysis of SMX in real water samples with the recoveries of 96.0-100.6%, the detection limits of 0.1 {mu}g L{sup -1}, and the linear ranges of 2.5-250.0 {mu}g L{sup -1}.

Comparison of analysis techniques by liquid scintillation and Cerenkov Effect for 40K quantification in aqueous samples

International Nuclear Information System (INIS)

Miranda C, L.; Davila R, J. I.; Lopez del R, H.; Mireles G, F.

2015-09-01

In this work the counting by liquid scintillation and Cerenkov Effect to quantify 40 K in aqueous samples was used. The performance of both techniques was studied by comparing the response of three commercial liquid scintillation OptiPhase HiSafe 3, Ultima Gold Ab and OptiPhase TriSafe, the vial type and presentation conditions of the sample for counting. In liquid scintillation, the ability to form homogeneous mixtures depended on the ionic strength of the aqueous solutions. The scintillator OptiPhase HiSafe 3 showed a greater charge capacity for solutions with high ionic strength (<3.4), while the scintillator OptiSafe TriSafe no form homogeneous mixtures for solutions of ionic strength higher than 0.3. Counting efficiencies for different proportions of sample and scintillator near 100% for the scintillators OptiSafe HiSafe 3 and Ultima Gold Ab were obtained. In the counting by Cerenkov Effect, the efficiency and sensitivity depended of the vial type; polyethylene vials were more suitable for counting that the glass vials. The sample volume had not significant effect on counting efficiency, obtaining an average value of 44.8% for polyethylene vials and 37.3% for glass vials. Therefore, the liquid scintillation was more efficient and sensitive for the measurement of 40 K in aqueous solutions. (Author)

Three-phase double-arc plasma for spectrochemical analysis of environmental samples.

Science.gov (United States)

Mohamed, M M; Ghatass, Z F; Shalaby, E A; Kotb, M M; El-Raey, M

2000-12-01

A new instrument, which uses a three-phase current to support a double-arc argon plasma torch for evaporation, atomization and excitation of solid or powder samples, is described. The sampling arc is ignited between the first and second electrode while the excitation arc is ignited between the second and third electrode. Aerosol generated from the sample (first electrode) is swept by argon gas, through a hole in the second electrode (carbon tubing electrode), into the excitation plasma. A tangential stream of argon gas is introduced through an inlet orifice as a coolant gas for the second electrode. This gas stream forces the excitation arc discharge to rotate reproducibly around the electrode surface. Discharge rotation increases the stability of the excitation plasma. Spectroscopic measurements are made directly in the current-carrying region of the excitation arc. An evaluation of each parameter influencing the device performance was performed. Analytical calibration curves were obtained for Fe, Al, K, and Pb. Finally, the present technique was applied for the analysis of environmental samples. The present method appears to have significant, low cost analytical utility for environmental measurements.

Sampling device for withdrawing a representative sample from single and multi-phase flows

Science.gov (United States)

Apley, Walter J.; Cliff, William C.; Creer, James M.

1984-01-01

A fluid stream sampling device has been developed for the purpose of obtaining a representative sample from a single or multi-phase fluid flow. This objective is carried out by means of a probe which may be inserted into the fluid stream. Individual samples are withdrawn from the fluid flow by sampling ports with particular spacings, and the sampling parts are coupled to various analytical systems for characterization of the physical, thermal, and chemical properties of the fluid flow as a whole and also individually.

Silica Modified with Polyaniline as a Potential Sorbent for Matrix Solid Phase Dispersion (MSPD and Dispersive Solid Phase Extraction (d-SPE of Plant Samples

Directory of Open Access Journals (Sweden)

Ireneusz Sowa

2018-03-01

Full Text Available Polyaniline (PANI is one of the best known conductive polymers with multiple applications. Recently, it was also used in separation techniques, mostly as a component of composites for solid-phase microextraction (SPME. In the present paper, sorbent obtained by in situ polymerization of aniline directly on silica gel particles (Si-PANI was used for dispersive solid phase extraction (d-SPE and matrix solid–phase extraction (MSPD. The efficiency of both techniques was evaluated with the use of high performance liquid chromatography with diode array detection (HPLC-DAD quantitative analysis. The quality of the sorbent was verified by Raman spectroscopy and microscopy combined with automated procedure using computer image analysis. For extraction experiments, triterpenes were chosen as model compounds. The optimal conditions were as follows: protonated Si-PANI impregnated with water, 160/1 sorbent/analyte ratio, 3 min of extraction time, 4 min of desorption time and methanolic solution of ammonia for elution of analytes. The proposed procedure was successfully used for pretreatment of plant samples.

Sampling techniques for thrips (Thysanoptera: Thripidae) in preflowering tomato.

Science.gov (United States)

Joost, P Houston; Riley, David G

2004-08-01

Sampling techniques for thrips (Thysanoptera: Thripidae) were compared in preflowering tomato plants at the Coastal Plain Experiment Station in Tifton, GA, in 2000 and 2003, to determine the most effective method of determining abundance of thrips on tomato foliage early in the growing season. Three relative sampling techniques, including a standard insect aspirator, a 946-ml beat cup, and an insect vacuum device, were compared for accuracy to an absolute method and to themselves for precision and efficiency of sampling thrips. Thrips counts of all relative sampling methods were highly correlated (R > 0.92) to the absolute method. The aspirator method was the most accurate compared with the absolute sample according to regression analysis in 2000. In 2003, all sampling methods were considered accurate according to Dunnett's test, but thrips numbers were lower and sample variation was greater than in 2000. In 2000, the beat cup method had the lowest relative variation (RV) or best precision, at 1 and 8 d after transplant (DAT). Only the beat cup method had RV values <25 for all sampling dates. In 2003, the beat cup method had the lowest RV value at 15 and 21 DAT. The beat cup method also was the most efficient method for all sample dates in both years. Frankliniella fusca (Pergande) was the most abundant thrips species on the foliage of preflowering tomato in both years of study at this location. Overall, the best thrips sampling technique tested was the beat cup method in terms of precision and sampling efficiency.

Methylmercury speciation in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique

Energy Technology Data Exchange (ETDEWEB)

Clarisse, Olivier [Trent University, Department of Chemistry, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8 (Canada)], E-mail: olivier.clarisse@umoncton.ca; Foucher, Delphine; Hintelmann, Holger [Trent University, Department of Chemistry, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8 (Canada)

2009-03-15

The diffusive gradient in thin film (DGT) technique was successfully used to monitor methylmercury (MeHg) speciation in the dissolved phase of a stratified boreal lake, Lake 658 of the Experimental Lakes Area (ELA) in Ontario, Canada. Water samples were conventionally analysed for MeHg, sulfides, and dissolved organic matter (DOM). MeHg accumulated by DGT devices was compared to MeHg concentration measured conventionally in water samples to establish MeHg speciation. In the epilimnion, MeHg was almost entirely bound to DOM. In the top of the hypolimnion an additional labile fraction was identified, and at the bottom of the lake a significant fraction of MeHg was potentially associated to colloidal material. As part of the METAALICUS project, isotope enriched inorganic mercury was applied to Lake 658 and its watershed for several years to establish the relationship between atmospheric Hg deposition and Hg in fish. Little or no difference in MeHg speciation in the dissolved phase was detected between ambient and spike MeHg. - Methylmercury speciation was determined in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique.

Methylmercury speciation in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique

International Nuclear Information System (INIS)

Clarisse, Olivier; Foucher, Delphine; Hintelmann, Holger

2009-01-01

The diffusive gradient in thin film (DGT) technique was successfully used to monitor methylmercury (MeHg) speciation in the dissolved phase of a stratified boreal lake, Lake 658 of the Experimental Lakes Area (ELA) in Ontario, Canada. Water samples were conventionally analysed for MeHg, sulfides, and dissolved organic matter (DOM). MeHg accumulated by DGT devices was compared to MeHg concentration measured conventionally in water samples to establish MeHg speciation. In the epilimnion, MeHg was almost entirely bound to DOM. In the top of the hypolimnion an additional labile fraction was identified, and at the bottom of the lake a significant fraction of MeHg was potentially associated to colloidal material. As part of the METAALICUS project, isotope enriched inorganic mercury was applied to Lake 658 and its watershed for several years to establish the relationship between atmospheric Hg deposition and Hg in fish. Little or no difference in MeHg speciation in the dissolved phase was detected between ambient and spike MeHg. - Methylmercury speciation was determined in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique

Solid Phase Characterization Of Heel Samples From Tank 241-C-110

International Nuclear Information System (INIS)

Page, J.S.; Cooke, G.A.; Pestovich, J.A.; Huber, H.J.

2011-01-01

During sluicing operations of tank 241-C-110, a significant amount of solids were unable to be retrieved. These solids (often referred to as the tank 'heel') were sampled in 2010 and chemically and mineralogically analyzed in the 222-S Laboratory. Additionally, dissolution tests were performed to identify the amount of undissolvable material after using multiple water contacts. This report covers the solid phase characterization of six samples from these tests using scanning electron microscopy, polarized light microscopy, and X-ray diffraction. The chemical analyses, particle size distribution analysis, and dissolution test results are reported separately. Two of the samples were from composites created from as-received material - Composite A and Composite B. The main phase in these samples was sodium-fluoride-phosphate hydrate (natrophosphate) - in the X-ray diffraction spectra, this phase was the only phase identifiable. Polarized light microscopy showed the presence of minor amounts of gibbsite and other phases. These phases were identified by scanning electron microscopy - energy dispersive X-ray spectroscopy as sodium aluminosilicates, sodium diuranate, and sodium strontium phosphate hydrate (nastrophite) crystals. The natrophosphate crystals in the scanning electron microscopy analysis showed a variety of erosive and dissolution features from perfectly shaped octahedral to well-rounded appearance. Two samples were from water-washed Composites A and B, with no change in mineralogy compared to the as-received samples. This is not surprising, since the water wash had only a short period of water contact with the material as opposed to the water dissolution tests. The last two samples were residual solids from the water dissolution tests. These tests included multiple additions of water at 15 C and 45 C. The samples were sieved to separate a coarser fraction of > 710 μm and a finer fraction of < 710 μm. These two fractions were analyzed separately. The coarser

BASIC BIOMECHANICAL CHARACTERISTICS OF THE SECOND PHASE (TSUKURI OF JUDO THROWING TECHNIQUE OSOTO GARI

Directory of Open Access Journals (Sweden)

Fadil Rexhepi

2011-09-01

Full Text Available In a sample of a total of 11 judoists - one was the Tori (thrower, and the other ten were uke (those who were thrown during the performance of throwing technique, was analyzed the second phase of throwing (tsukuri judo technique osoto gari. Tori is an active athlete superior quality (master, body mass = 72 kg, and all the other, who were thrown (uke differ from each other as the weight and height of the body concerned. The average of their body weight was 73.8 kg, which means that it is almost even with body mass of tori. For data collection was used a three-dimensional motion analysis system APAS (Ariel Performance Analysis System. Tsukuri is the phase where occur most actions of reaping leg. The second phase (tsukuri begins when tori detach his right foot and lasts until the beginning of reaping opponent's leg, on which was concentrated its weight (uke's weight. The parameters that describe the effect of the reaping leg in the second phase of technique osoto gari are crucial for the successful execution of this leg technique. For the analysis of the second phase of the throw were selected 14 variables that describe the position of the body and certain body parts of both athletes, velocity parameters of tori's reaping leg and the duration of this phase (time. The role of the tori's standing leg is to maintain a stable position during this phase, while the other leg quickly and in full force acts reaping. The smallest angle of the knee joint of standing leg during the second phase was 130.84 °. Before the moment of reaping, or detachment of uke`s feet from the mat, standing leg has a tendency to extension in the knee joint, which impacts positively on raising the tori's body center of mass. Height tori's body center of mass at the beginning phase was 87.79 cm. As a result of tori's action by pulling onto uke, but little to his left side, the uke`s center of mass at the end of this phase is moved laterally to 6.10 cm. The results show quite

Air sampling with solid phase microextraction

Science.gov (United States)

Martos, Perry Anthony

There is an increasing need for simple yet accurate air sampling methods. The acceptance of new air sampling methods requires compatibility with conventional chromatographic equipment, and the new methods have to be environmentally friendly, simple to use, yet with equal, or better, detection limits, accuracy and precision than standard methods. Solid phase microextraction (SPME) satisfies the conditions for new air sampling methods. Analyte detection limits, accuracy and precision of analysis with SPME are typically better than with any conventional air sampling methods. Yet, air sampling with SPME requires no pumps, solvents, is re-usable, extremely simple to use, is completely compatible with current chromatographic equipment, and requires a small capital investment. The first SPME fiber coating used in this study was poly(dimethylsiloxane) (PDMS), a hydrophobic liquid film, to sample a large range of airborne hydrocarbons such as benzene and octane. Quantification without an external calibration procedure is possible with this coating. Well understood are the physical and chemical properties of this coating, which are quite similar to those of the siloxane stationary phase used in capillary columns. The log of analyte distribution coefficients for PDMS are linearly related to chromatographic retention indices and to the inverse of temperature. Therefore, the actual chromatogram from the analysis of the PDMS air sampler will yield the calibration parameters which are used to quantify unknown airborne analyte concentrations (ppb v to ppm v range). The second fiber coating used in this study was PDMS/divinyl benzene (PDMS/DVB) onto which o-(2,3,4,5,6- pentafluorobenzyl) hydroxylamine (PFBHA) was adsorbed for the on-fiber derivatization of gaseous formaldehyde (ppb v range), with and without external calibration. The oxime formed from the reaction can be detected with conventional gas chromatographic detectors. Typical grab sampling times were as small as 5 seconds

Application of immersion phased array UT technique in nickel based alloy weld

International Nuclear Information System (INIS)

Hirasawa, Taiji; Nagai, Satoshi; Murakami, Koji; Yuguchi, Yasuhiro; Ootsubo, Tooru; Naruse, Katsuhiko

2007-01-01

The improvement of defect detection and sizing capabilities for nondestructive inspection technique has been required in order to ensure the reliable operation and life extension of nuclear power plant. Immersion phased array UT technique which is not affected the surface geometry of welds has been developed for inspection of BWR internals such as shroud, shroud support, and so on. Phased array UT technique was applied for shroud support mockup specimen with fatigue crack and partially SCC. From the experimental results, the superior performance of phased array UT for the RPV outside and inside inspection was shown. (author)

Green approaches in sample preparation of bioanalytical samples prior to chromatographic analysis.

Science.gov (United States)

Filippou, Olga; Bitas, Dimitrios; Samanidou, Victoria

2017-02-01

Sample preparation is considered to be the most challenging step of the analytical procedure, since it has an effect on the whole analytical methodology, therefore it contributes significantly to the greenness or lack of it of the entire process. The elimination of the sample treatment steps, pursuing at the same time the reduction of the amount of the sample, strong reductions in consumption of hazardous reagents and energy also maximizing safety for operators and environment, the avoidance of the use of big amount of organic solvents, form the basis for greening sample preparation and analytical methods. In the last decade, the development and utilization of greener and sustainable microextraction techniques is an alternative to classical sample preparation procedures. In this review, the main green microextraction techniques (solid phase microextraction, stir bar sorptive extraction, hollow-fiber liquid phase microextraction, dispersive liquid - liquid microextraction, etc.) will be presented, with special attention to bioanalytical applications of these environment-friendly sample preparation techniques which comply with the green analytical chemistry principles. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of microcontaminants in aqueous samples by fully automated on-line solid-phase extraction-gas chromatography-mass selective detection.

NARCIS (Netherlands)

Louter, A.J.H.; van Beekvelt, C.A.; Cid Montanes, P.; Slobodník, J.; Vreuls, J.J.; Brinkman, U.A.T.

1996-01-01

The trace-level analysis of unknown organic pollutants in water requires the use of fast and sensitive methods which also provide structural information. In the present study, an on-line technique was used which combines sample preparation by means of solid-phase extraction (SPE) on a small

Applications of Liquid-Phase Microextraction in the Sample Preparation of Environmental Solid Samples

OpenAIRE

Helena Prosen

2014-01-01

Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc.) published in the last decade. Several...

Investigation of Thermal Interface Materials Using Phase-Sensitive Transient Thermoreflectance Technique: Preprint

Energy Technology Data Exchange (ETDEWEB)

Feng, X.; King, C.; DeVoto, D.; Mihalic, M.; Narumanchi, S.

2014-08-01

With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 um bondline thickness) was 3 to 5 W/(m-K) and the contact resistance was 5 to 10 mm2-K/W. For the Btech thermoplastic material (45 to 80 μm bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m-K) and the contact resistance was 2 to 5 mm2-K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.

Use of nuclear technique in samples for agricultural purposes

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Kerley A. P. de; Sperling, Eduardo Von, E-mail: kerley@ufmg.br, E-mail: kerleyfisica@yahoo.com.br [Department of Sanitary and Environmental Engineering Federal University of Minas Gerais, Belo Horizonte (Brazil); Menezes, Maria Angela B. C.; Jacomino, Vanusa M.F. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2013-01-15

The concern related to environment is growing. Due to this, it is needed to determine chemical elements in a large range of concentration. The neutron activation technique (NAA) determines the elemental composition by the measurement of artificial radioactivity in a sample that was submitted to a neutron flux. NAA is a sensitive and accurate technique with low detection limits. An example of application of NAA was the measurement of concentrations of rare earth elements (REE) in waste samples of phosphogypsum (PG) and cerrado soil samples (clayey and sandy soils). Additionally, a soil reference material of the International Atomic Energy Agency (IAEA) was also analyzed. The REE concentration in PG samples was two times higher than those found in national fertilizers, (total of 4,000 mg kg{sup -1}), 154 times greater than the values found in the sandy soil (26 mg kg{sup -1}) and 14 times greater than the in clayey soil (280 mg kg{sup -1}). The experimental results for the reference material were inside the uncertainty of the certified values pointing out the accuracy of the method (95%). The determination of La, Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Lu in the samples and reference material confirmed the versatility of the technique on REE determination in soil and phosphogypsum samples that are matrices for agricultural interest. (author)

Use of nuclear technique in samples for agricultural purposes

International Nuclear Information System (INIS)

Oliveira, Kerley A. P. de; Sperling, Eduardo Von; Menezes, Maria Angela B. C.; Jacomino, Vanusa M.F.

2013-01-01

The concern related to environment is growing. Due to this, it is needed to determine chemical elements in a large range of concentration. The neutron activation technique (NAA) determines the elemental composition by the measurement of artificial radioactivity in a sample that was submitted to a neutron flux. NAA is a sensitive and accurate technique with low detection limits. An example of application of NAA was the measurement of concentrations of rare earth elements (REE) in waste samples of phosphogypsum (PG) and cerrado soil samples (clayey and sandy soils). Additionally, a soil reference material of the International Atomic Energy Agency (IAEA) was also analyzed. The REE concentration in PG samples was two times higher than those found in national fertilizers, (total of 4,000 mg kg -1 ), 154 times greater than the values found in the sandy soil (26 mg kg -1 ) and 14 times greater than the in clayey soil (280 mg kg -1 ). The experimental results for the reference material were inside the uncertainty of the certified values pointing out the accuracy of the method (95%). The determination of La, Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Lu in the samples and reference material confirmed the versatility of the technique on REE determination in soil and phosphogypsum samples that are matrices for agricultural interest. (author)

Development of analytical techniques for safeguards environmental samples at JAEA

International Nuclear Information System (INIS)

Sakurai, Satoshi; Magara, Masaaki; Usuda, Shigekazu; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, Chi-Gyu; Yasuda, Kenichiro; Inagawa, Jun; Suzuki, Daisuke; Iguchi, Kazunari; Kokubu, Yoko S.; Miyamoto, Yutaka; Ohzu, Akira

2007-01-01

JAEA has been developing, under the auspices of the Ministry of Education, Culture, Sports, Science and Technology of Japan, analytical techniques for ultra-trace amounts of nuclear materials in environmental samples in order to contribute to the strengthened safeguards system. Development of essential techniques for bulk and particle analysis, as well as screening, of the environmental swipe samples has been established as ultra-trace analytical methods of uranium and plutonium. In January 2003, JAEA was qualified, including its quality control system, as a member of the JAEA network analytical laboratories for environmental samples. Since 2004, JAEA has conducted the analysis of domestic and the IAEA samples, through which JAEA's analytical capability has been verified and improved. In parallel, advanced techniques have been developed in order to expand the applicability to the samples of various elemental composition and impurities and to improve analytical accuracy and efficiency. This paper summarizes the trace of the technical development in environmental sample analysis at JAEA, and refers to recent trends of research and development in this field. (author)

Magnetic separation techniques in sample preparation for biological analysis: a review.

Science.gov (United States)

He, Jincan; Huang, Meiying; Wang, Dongmei; Zhang, Zhuomin; Li, Gongke

2014-12-01

Sample preparation is a fundamental and essential step in almost all the analytical procedures, especially for the analysis of complex samples like biological and environmental samples. In past decades, with advantages of superparamagnetic property, good biocompatibility and high binding capacity, functionalized magnetic materials have been widely applied in various processes of sample preparation for biological analysis. In this paper, the recent advancements of magnetic separation techniques based on magnetic materials in the field of sample preparation for biological analysis were reviewed. The strategy of magnetic separation techniques was summarized. The synthesis, stabilization and bio-functionalization of magnetic nanoparticles were reviewed in detail. Characterization of magnetic materials was also summarized. Moreover, the applications of magnetic separation techniques for the enrichment of protein, nucleic acid, cell, bioactive compound and immobilization of enzyme were described. Finally, the existed problems and possible trends of magnetic separation techniques for biological analysis in the future were proposed. Copyright © 2014 Elsevier B.V. All rights reserved.

The electron transport problem sampling by Monte Carlo individual collision technique

International Nuclear Information System (INIS)

Androsenko, P.A.; Belousov, V.I.

2005-01-01

The problem of electron transport is of most interest in all fields of the modern science. To solve this problem the Monte Carlo sampling has to be used. The electron transport is characterized by a large number of individual interactions. To simulate electron transport the 'condensed history' technique may be used where a large number of collisions are grouped into a single step to be sampled randomly. Another kind of Monte Carlo sampling is the individual collision technique. In comparison with condensed history technique researcher has the incontestable advantages. For example one does not need to give parameters altered by condensed history technique like upper limit for electron energy, resolution, number of sub-steps etc. Also the condensed history technique may lose some very important tracks of electrons because of its limited nature by step parameters of particle movement and due to weakness of algorithms for example energy indexing algorithm. There are no these disadvantages in the individual collision technique. This report presents some sampling algorithms of new version BRAND code where above mentioned technique is used. All information on electrons was taken from Endf-6 files. They are the important part of BRAND. These files have not been processed but directly taken from electron information source. Four kinds of interaction like the elastic interaction, the Bremsstrahlung, the atomic excitation and the atomic electro-ionization were considered. In this report some results of sampling are presented after comparison with analogs. For example the endovascular radiotherapy problem (P2) of QUADOS2002 was presented in comparison with another techniques that are usually used. (authors)

Solid phase separation technique for use in radioimmunoassays

International Nuclear Information System (INIS)

Tu, J.I.

1979-01-01

A radioimmunoassay procedure, and article of manufacture for carrying out that procedure, are disclosed herein. The solid phase separation technique utilized in the radioimmunoassay of this invention utilizes a test tube, the internal surface of which has been coated with two antibody layers

Trial on MR portal blood flow measurement with phase contrast technique

International Nuclear Information System (INIS)

Tsunoda, Masatoshi; Kimoto, Shin; Togami, Izumi

1991-01-01

Portal blood flow measurement is considered to be important for the analysis of hemodynamics in various liver diseases. The Doppler ultrasound method has been used extensively during the past several years for measuring portal blood flow, as a non-invasive method. However, the Doppler ultrasound technique do not allow the portal blood flow to be measured in cases of obesity, with much intestinal gas, and so on. In this study, we attempted to measure the blood flow in the main trunk of portal vein as an application of MR phase contrast technique to the abdominal region. In the flow phantom study, the flow volumes and the velocities measured by phase contrast technique showed a close correlation with those measured by electromagnetic flowmeter. In the clinical study with 10 healthy volunteers, various values of portal blood flow were obtained. Mean portal blood flow could be measured within the measuring time (about 8 minutes) under natural breathing conditions. Phase contrast technique is considered to be useful for the non-invasive measurement of portal blood flow. (author)

Optical Techniques for Millimeter-Wave Phased Array Communications Antennas

National Research Council Canada - National Science Library

Edge, Colin

1998-01-01

The scope of this program was to study the application of optical techniques to signal distribution and beamforming networks in phased array antennas for Army mobile tactical communications systems...

The potential of organic (electrospray- and atmospheric pressure chemical ionisation) mass spectrometric techniques coupled to liquid-phase separation for speciation analysis.

Science.gov (United States)

Rosenberg, Erwin

2003-06-06

The use of mass spectrometry based on atmospheric pressure ionisation techniques (atmospheric pressure chemical ionisation, APCI, and electrospray ionisation, ESI) for speciation analysis is reviewed with emphasis on the literature published in and after 1999. This report accounts for the increasing interest that atmospheric pressure ionisation techniques, and in particular ESI, have found in the past years for qualitative and quantitative speciation analysis. In contrast to element-selective detectors, organic mass spectrometric techniques provide information on the intact metal species which can be used for the identification of unknown species (particularly with MS-MS detection) or the confirmation of the actual presence of species in a given sample. Due to the complexity of real samples, it is inevitable in all but the simplest cases to couple atmospheric pressure MS detection to a separation technique. Separation in the liquid phase (capillary electrophoresis or liquid chromatography in reversed phase, ion chromatographic or size-exclusion mode) is particularly suitable since the available techniques cover a very wide range of analyte polarities and molecular mass. Moreover, derivatisation can normally be avoided in liquid-phase separation. Particularly in complex environmental or biological samples, separation in one dimension is not sufficient for obtaining adequate resolution for all relevant species. In this case, multi-dimensional separation, based on orthogonal separation techniques, has proven successful. ESI-MS is also often used in parallel with inductively coupled plasma MS detection. This review is structured in two parts. In the first, the fundamentals of atmospheric pressure ionisation techniques are briefly reviewed. The second part of the review discusses recent applications including redox species, use of ESI-MS for structural elucidation of metal complexes, characterisation and quantification of small organometallic species with relevance to

Liquid-phase sample preparation method for real-time monitoring of airborne asbestos fibers by dual-mode high-throughput microscopy.

Science.gov (United States)

Cho, Myoung-Ock; Kim, Jung Kyung; Han, Hwataik; Lee, Jeonghoon

2013-01-01

Asbestos that had been used widely as a construction material is a first-level carcinogen recognized by the World Health Organization. It can be accumulated in body by inhalation causing virulent respiratory diseases including lung cancer. In our previous study, we developed a high-throughput microscopy (HTM) system that can minimize human intervention accompanied by the conventional phase contrast microscopy (PCM) through automated counting of fibrous materials and thus significantly reduce analysis time and labor. Also, we attempted selective detection of chrysotile using DksA protein extracted from Escherichia coli through a recombinant protein production technique, and developed a dual-mode HTM (DM-HTM) by upgrading the HTM device. We demonstrated that fluorescently-labeled chrysotile asbestos fibers can be identified and enumerated automatically among other types of asbestos fibers or non-asbestos particles in a high-throughput manner through a newly modified HTM system for both reflection and fluorescence imaging. However there is a limitation to apply DM-HTM to airborne sample with current air collecting method due to the difficulty of applying the protein to dried asbestos sample. Here, we developed a technique for preparing liquid-phase asbestos sample using an impinger normally used to collect odor molecules in the air. It would be possible to improve the feasibility of the dual-mode HTM by integrating a sample preparation unit for making collected asbestos sample dispersed in a solution. The new technique developed for highly sensitive and automated asbestos detection can be a potential alternative to the conventional manual counting method, and it may be applied on site as a fast and reliable environmental monitoring tool.

Manipulation of biological samples using micro and nano techniques.

Science.gov (United States)

Castillo, Jaime; Dimaki, Maria; Svendsen, Winnie Edith

2009-01-01

The constant interest in handling, integrating and understanding biological systems of interest for the biomedical field, the pharmaceutical industry and the biomaterial researchers demand the use of techniques that allow the manipulation of biological samples causing minimal or no damage to their natural structure. Thanks to the advances in micro- and nanofabrication during the last decades several manipulation techniques offer us the possibility to image, characterize and manipulate biological material in a controlled way. Using these techniques the integration of biomaterials with remarkable properties with physical transducers has been possible, giving rise to new and highly sensitive biosensing devices. This article reviews the different techniques available to manipulate and integrate biological materials in a controlled manner either by sliding them along a surface (2-D manipulation), by grapping them and moving them to a new position (3-D manipulation), or by manipulating and relocating them applying external forces. The advantages and drawbacks are mentioned together with examples that reflect the state of the art of manipulation techniques for biological samples (171 references).

The electron transport problem sampling by Monte Carlo individual collision technique

Energy Technology Data Exchange (ETDEWEB)

Androsenko, P.A.; Belousov, V.I. [Obninsk State Technical Univ. of Nuclear Power Engineering, Kaluga region (Russian Federation)

2005-07-01

The problem of electron transport is of most interest in all fields of the modern science. To solve this problem the Monte Carlo sampling has to be used. The electron transport is characterized by a large number of individual interactions. To simulate electron transport the 'condensed history' technique may be used where a large number of collisions are grouped into a single step to be sampled randomly. Another kind of Monte Carlo sampling is the individual collision technique. In comparison with condensed history technique researcher has the incontestable advantages. For example one does not need to give parameters altered by condensed history technique like upper limit for electron energy, resolution, number of sub-steps etc. Also the condensed history technique may lose some very important tracks of electrons because of its limited nature by step parameters of particle movement and due to weakness of algorithms for example energy indexing algorithm. There are no these disadvantages in the individual collision technique. This report presents some sampling algorithms of new version BRAND code where above mentioned technique is used. All information on electrons was taken from Endf-6 files. They are the important part of BRAND. These files have not been processed but directly taken from electron information source. Four kinds of interaction like the elastic interaction, the Bremsstrahlung, the atomic excitation and the atomic electro-ionization were considered. In this report some results of sampling are presented after comparison with analogs. For example the endovascular radiotherapy problem (P2) of QUADOS2002 was presented in comparison with another techniques that are usually used. (authors)

NAIL SAMPLING TECHNIQUE AND ITS INTERPRETATION

OpenAIRE

TZAR MN; LEELAVATHI M

2011-01-01

The clinical suspicion of onychomyosis based on appearance of the nails, requires culture for confirmation. This is because treatment requires prolonged use of systemic agents which may cause side effects. One of the common problems encountered is improper nail sampling technique which results in loss of essential information. The unfamiliar terminologies used in reporting culture results may intimidate physicians resulting in misinterpretation and hamper treatment decision. This article prov...

Improvement of colloid sampling techniques in groundwater and actinide characterisation of the groundwater systems at Gorleben (FRG) and El Berrocal (E)

International Nuclear Information System (INIS)

Dearlove, J.P.L.; Longworth, G.; Ivanovich, M.

1990-08-01

Two sites, the Gorleben site (FRG) and the El Berrocal Experimental station (E) have been studied to evaluate different sampling and analytical techniques for the characterisation of particulates (> 1000 nm size), colloids (1-1000 nm size) and the solution phase (<1 nm) in groundwaters in terms of their physical, chemical and actinide composition. The uptake characteristics of the field ultrafiltration system used to separate the colloid fraction from the solution phase in the groundwater have also been studied. (Author)

Sample preparation techniques for (p, X) spectrometry

International Nuclear Information System (INIS)

Whitehead, N.E.

1985-01-01

Samples are ashed at low temperature, using oxygen plasma; a rotary evaporator, and freeze drying speeded up the ashing. The new design of apparatus manufactured was only 10 watt but was as efficient as a 200 watt commercial machine; a circuit diagram is included. Samples of hair and biopsy samples of skin were analysed by the technique. A wool standard was prepared for interlaboratory comparison exercises. It was based on New Zealand merino sheep wool and was 2.9 kg in weight. A washing protocol was developed, which preserves most of the trace element content. The wool was ground in liquid nitrogen using a plastic pestle and beaker, driven by a rotary drill press. (author)

The phase field technique for modeling multiphase materials

Science.gov (United States)

Singer-Loginova, I.; Singer, H. M.

2008-10-01

This paper reviews methods and applications of the phase field technique, one of the fastest growing areas in computational materials science. The phase field method is used as a theory and computational tool for predictions of the evolution of arbitrarily shaped morphologies and complex microstructures in materials. In this method, the interface between two phases (e.g. solid and liquid) is treated as a region of finite width having a gradual variation of different physical quantities, i.e. it is a diffuse interface model. An auxiliary variable, the phase field or order parameter \\phi(\\vec{x}) , is introduced, which distinguishes one phase from the other. Interfaces are identified by the variation of the phase field. We begin with presenting the physical background of the phase field method and give a detailed thermodynamical derivation of the phase field equations. We demonstrate how equilibrium and non-equilibrium physical phenomena at the phase interface are incorporated into the phase field methods. Then we address in detail dendritic and directional solidification of pure and multicomponent alloys, effects of natural convection and forced flow, grain growth, nucleation, solid-solid phase transformation and highlight other applications of the phase field methods. In particular, we review the novel phase field crystal model, which combines atomistic length scales with diffusive time scales. We also discuss aspects of quantitative phase field modeling such as thin interface asymptotic analysis and coupling to thermodynamic databases. The phase field methods result in a set of partial differential equations, whose solutions require time-consuming large-scale computations and often limit the applicability of the method. Subsequently, we review numerical approaches to solve the phase field equations and present a finite difference discretization of the anisotropic Laplacian operator.

Application of Phase-Field Techniques to Hydraulically- and Deformation-Induced Fracture.

Energy Technology Data Exchange (ETDEWEB)

Culp, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Miller, Nathan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schweizer, Laura [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-08-01

Phase-field techniques provide an alternative approach to fracture problems which mitigate some of the computational expense associated with tracking the crack interface and the coalescence of individual fractures. The technique is extended to apply to hydraulically driven fracture such as would occur during fracking or CO₂ sequestration. Additionally, the technique is applied to a stainless steel specimen used in the Sandia Fracture Challenge. It was found that the phase-field model performs very well, at least qualitatively, in both deformation-induced fracture and hydraulically-induced fracture, though spurious hourglassing modes were observed during coupled hydralically-induced fracture. Future work would include performing additional quantitative benchmark tests and updating the model as needed.

Teknik Sampling Snowball dalam Penelitian Lapangan

Directory of Open Access Journals (Sweden)

Nina Nurdiani

2014-12-01

Full Text Available Field research can be associated with both qualitative and quantitative research methods, depending on the problems faced and the goals to be achieved. The success of data collection in the field research depends on the determination of the appropriate sampling technique, to obtain accurate data, and reliably. In studies that have problems related to specific issues, requiring a non-probability sampling techniques one of which is the snowball sampling technique. This technique is useful for finding, identifying, selecting and taking samples in a network or chain of relationships. Phased implementation procedures performed through interviews and questionnaires. Snowball sampling technique has strengths and weaknesses in its application. Field research housing sector become the case study to explain this sampling technique.

Development of phase-contrast imaging technique for material science and medical science applications

International Nuclear Information System (INIS)

Kashyap, Y.S.; Roy, Tushar; Sarkar, P.S; Shukla, Mayank; Yadav, P.S; Sinha, Amar; Verma, Vishnu; Ghosh, A.K.

2007-07-01

In-line phase contrast imaging technique is an emerging method for study of materials such as carbon fibres, carbon composite materials, polymers etc. These represent the class of materials for which x-ray attenuation cross-section is very small. Similarly, this technique is also well suited for imaging of soft materials such as tissues, distinguishing between tumour and normal tissue. Thus this method promises a far better contrast for low x-ray absorbing substances than the conventional radiography method for material and medical science applications. Though the conventional radiography technique has been carried out for decades, the phase-imaging technique is being demonstrated for the first time within, the country. We have set up an experimental facility for phase contrast imaging using a combination of x-ray CCD detector and a microfocus x-ray source. This facility is dedicated for micro-imaging experiments such as micro-tomography and high resolution phase contrast experiments. In this report, the results of phase contrast imaging using microfocus source and ELETTRA, synchrotron source are discussed. We have also discussed the basic design and heat load calculation for upcoming imaging beamline at Indus-II, RRCAT, Indore. (author)

Solvent-free sample preparation by headspace solid-phase microextraction applied to the tracing of n-butyl nitrite abuse.

Science.gov (United States)

Tytgat, J; Daenens, P

1996-01-01

The most common alkyl nitrites encountered in forensic toxicology are iso-butyl, n-butyl and iso-pentyl(amyl) nitrites. All have become popular as an aphrodisiac, especially among the homosexual population. Alkyl nitrites are a volatile and unstable group of compounds, which hydrolyse in aqueous matrices to the alcohol and nitrite ion. Here we describe a fast, clean and sensitive procedure for the detection of hydrolysed n-butyl nitrite in whole human blood using a new, solvent-free sampling technique, the headspace solid-phase micro-extraction (HSPME), combined with GC/FID analysis. Sample preparation was investigated using two different stationary phases (100 microns polydimethylsiloxane and 85 microns polyacrylate), coating a fused silica fibre. The effect of different sampling times at fixed temperatures was also studied. Our results demonstrate that the HSPME/GC/FID procedure allows tracing of n-butyl nitrite abuse and detects hydrolysed n-butyl nitrite, i.e., released n-butanol, in whole blood at the 1 ng/mL level.

Respiratory motion sampling in 4DCT reconstruction for radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Chi Yuwei; Liang Jian; Qin Xu; Yan Di [Department of Radiation Oncology, Columbia University, New York, New York 10032 (United States); Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan 48073 (United States)

2012-04-15

Purpose: Phase-based and amplitude-based sorting techniques are commonly used in four-dimensional CT (4DCT) reconstruction. However, effect of these sorting techniques on 4D dose calculation has not been explored. In this study, the authors investigated a candidate 4DCT sorting technique by comparing its 4D dose calculation accuracy with that for phase-based and amplitude-based sorting techniques.Method: An optimization model was formed using organ motion probability density function (PDF) in the 4D dose convolution. The objective function for optimization was defined as the maximum difference between the expected 4D dose in organ of interest and the 4D dose calculated using a 4DCT sorted by a candidate sampling method. Sorting samples, as optimization variables, were selected on the respiratory motion PDF assessed during the CT scanning. Breathing curves obtained from patients' 4DCT scanning, as well as 3D dose distribution from treatment planning, were used in the study. Given the objective function, a residual error analysis was performed, and k-means clustering was found to be an effective sampling scheme to improve the 4D dose calculation accuracy and independent with the patient-specific dose distribution. Results: Patient data analysis demonstrated that the k-means sampling was superior to the conventional phase-based and amplitude-based sorting and comparable to the optimal sampling results. For phase-based sorting, the residual error in 4D dose calculations may not be further reduced to an acceptable accuracy after a certain number of phases, while for amplitude-based sorting, k-means sampling, and the optimal sampling, the residual error in 4D dose calculations decreased rapidly as the number of 4DCT phases increased to 6.Conclusion: An innovative phase sorting method (k-means method) is presented in this study. The method is dependent only on tumor motion PDF. It could provide a way to refine the phase sorting in 4DCT reconstruction and is effective

Correcting Classifiers for Sample Selection Bias in Two-Phase Case-Control Studies

Science.gov (United States)

Theis, Fabian J.

2017-01-01

Epidemiological studies often utilize stratified data in which rare outcomes or exposures are artificially enriched. This design can increase precision in association tests but distorts predictions when applying classifiers on nonstratified data. Several methods correct for this so-called sample selection bias, but their performance remains unclear especially for machine learning classifiers. With an emphasis on two-phase case-control studies, we aim to assess which corrections to perform in which setting and to obtain methods suitable for machine learning techniques, especially the random forest. We propose two new resampling-based methods to resemble the original data and covariance structure: stochastic inverse-probability oversampling and parametric inverse-probability bagging. We compare all techniques for the random forest and other classifiers, both theoretically and on simulated and real data. Empirical results show that the random forest profits from only the parametric inverse-probability bagging proposed by us. For other classifiers, correction is mostly advantageous, and methods perform uniformly. We discuss consequences of inappropriate distribution assumptions and reason for different behaviors between the random forest and other classifiers. In conclusion, we provide guidance for choosing correction methods when training classifiers on biased samples. For random forests, our method outperforms state-of-the-art procedures if distribution assumptions are roughly fulfilled. We provide our implementation in the R package sambia. PMID:29312464

Characterization of Some Iraqi Archaeological Samples Using IBA, Analytical X-ray and Other Complementary Techniques

International Nuclear Information System (INIS)

Al-Sarraj, Ziyad Shihab; Damboos, Hassan I; Roumie, Mohamad

2012-01-01

The present work aimed at investigating the compositions and microstructures of some archaeological samples which dated back to various periods of the ancient Iraqi civilizations using PIXE, XRF, XRD, and SEM techniques. The models selected for the study (ceramics, glaze, etc.) were diverse in size and nature, therefore a limited number of samples were then butted from them by a small diamond wheel. Conventional powder metallurgy method was then used to prepare the samples. Dried samples were then coated with a thin layer of carbon, and analyzed using the ion beam accelerator of the LAEC. Three other groups of samples were also prepared for the purpose of analysis by X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscope (SEM). Analysis results of the chemical composition showed good agreement between the various techniques as well as for phases, while the fine structure analysis obtained by optical and scanning microscopy exhibited features of a structure where it got an intensified densification in the final stage of sintering and accompanied by quasi-homogeneous distribution of the closed pores. This will lead to the conclusion that the temperature used for sintering by ancient Iraqi was sufficient and it may fall in the range between 950-1200°C, also the mixes and the forming methods used by them, were both suitable to obtain good sintered bodies with even distribution of pores. A ring-shaped trace noticed in SEM micrographs need more work and study to explain what it is?

Yield strength, shear stress and toughness of YBCO samples textured by Bridgman technique

International Nuclear Information System (INIS)

Roa, J J; Capdevila, X G; Martinez, M; Segarra, M; Jimenez-Pique, E

2008-01-01

Mechanical properties of the orthorhombic phase of YBa 2 Cu 3 O 7-δ (Y-123) at room temperature have been investigated at different applied loads using nanoindentation technique. The study was carried out for several monodomains on the (001) planes for textured Bridgman samples with dispersed Y 2 BaCuO 5 (Y-211) particles as pinning centers. The yield strength (σ ys ), shear stress (τ m ) and toughness (K IC ) of Y123/Y211composite was determined at different applied loads. First and second mechanical properties have been calculated though the Hertz equations and the last one with Lawn et al. equations. Finally, the ultra-low imprints obtained by nanoindentation have been correlated with parameters obtained by Field Emission Scanning Electron Microscope (FE-SEM)

Innovative directional and position specific sampling technique

International Nuclear Information System (INIS)

Hutzel, W.J.; Hill, J.L. III; Foster, E.L.

1994-01-01

UTD, Incorporated has developed a unique real-time, in-situ POsition LOcation (POLO) device which will directly enhance the Department of Energy's Environmental Restoration and Waste Management Program through improvements to finding contamination, identifying extent of contamination, remediating, and finally monitoring sites. POLO is smaller than existing technology and is unaffected by the presence of steel and other magnetic materials. The size of the device offers for the first time, the possibility to accurately determine the location of a penetrometer. It will be usable, in its present form, to map the position of a sampling device as that device is inserted into the ground. A three phase program was proposed to DOE to take the POLO System through the three levels of maturity prior to commercialization. Phase 1 included the design and testing of individual components of the device and met or exceeded success criteria. Phase 2 has included laboratory-scale tracking experiments of the integrated POLO System that have met or exceeded the success criterion as well. The success criterion is to demonstrate path tracking accuracy with a total error of less than 0.50% of the distance traveled for distances less than 70 meters. In Phase 3 we will develop and test a full-scale POLO System and conclude with a field demonstration. The goal of the Phase 3 effort is to achieve the same 0.50% accuracy or better with respect to the distance traveled for distances less than 70 meters in the field as was demonstrated in laboratory tests in the earlier phases. The final report details the design of a realistic laboratory-scale penetrometer path and describes the POLO tracking experiments that were conducted. Plans for demonstrations as well as commercialization and technology transfer with DOE field sites are described, highlighting the expected smooth transition to full-scale production

Evaluation of phased array UT conditions using ultrasonic visualization technique

International Nuclear Information System (INIS)

Furukawa, Takashi; Komura, Ichirou

2008-01-01

Phased array provides many advantages over conventional ultrasonic testing method, but phased array has also limitations. This paper describes typical results of the experimental sound field analysis generated from the array probe. A photo-elastic ultrasonic visualization technique was applied in this study. The sound fields of shear wave generated from the array probe was equivalent to that from the fixed angle probe. (author)

Derivative spectrum chromatographic method for the determination of trimethoprim in honey samples using an on-line solid-phase extraction technique.

Science.gov (United States)

Uchiyama, Kazuhisa; Kondo, Mari; Yokochi, Rika; Takeuchi, Yuri; Yamamoto, Atsushi; Inoue, Yoshinori

2011-07-01

A simple, selective and rapid analytical method for determination of trimethoprim (TMP) in honey samples was developed and validated. This method is based on a SPE technique followed by HPLC with photodiode array detection. After dilution and filtration, aliquots of 500 μL honey samples were directly injected to an on-line SPE HPLC system. TMP was extracted on an RP SPE column, and separated on a hydrophilic interaction chromatography column during HPLC analysis. At the first detection step, the noise level of the photodiode array data was reduced with two-dimensional equalizer filtering, and then the smoothed data were subjected to derivative spectrum chromatography. On the second-derivative chromatogram at 254 nm, the limit of detection and the limit of quantification of TMP in a honey sample were 5 and 10 ng/g, respectively. The proposed method showed high accuracy (60-103%) with adequate sensitivity for TMP monitoring in honey samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nuclear analytical techniques and their application to environmental samples

International Nuclear Information System (INIS)

Lieser, K.H.

1986-01-01

A survey is given on nuclear analytical techniques and their application to environmental samples. Measurement of the inherent radioactivity of elements or radionuclides allows determination of natural radioelements (e.g. Ra), man-made radioelements (e.g. Pu) and radionuclides in the environment. Activation analysis, in particular instrumental neutron activation analysis, is a very reliable and sensitive method for determination of a great number of trace elements in environmental samples, because the most abundant main constituents are not activated. Tracer techniques are very useful for studies of the behaviour and of chemical reactions of trace elements and compounds in the environment. Radioactive sources are mainly applied for excitation of characteristic X-rays (X-ray fluorescence analysis). (author)

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

Error analysis of the phase-shifting technique when applied to shadow moire

International Nuclear Information System (INIS)

Han, Changwoon; Han Bongtae

2006-01-01

An exact solution for the intensity distribution of shadow moire fringes produced by a broad spectrum light is presented. A mathematical study quantifies errors in fractional fringe orders determined by the phase-shifting technique, and its validity is corroborated experimentally. The errors vary cyclically as the distance between the reference grating and the specimen increases. The amplitude of the maximum error is approximately 0.017 fringe, which defines the theoretical limit of resolution enhancement offered by the phase-shifting technique

Micro and Nano Techniques for the Handling of Biological Samples

DEFF Research Database (Denmark)

Micro and Nano Techniques for the Handling of Biological Samples reviews the different techniques available to manipulate and integrate biological materials in a controlled manner, either by sliding them along a surface (2-D manipulation), or by gripping and moving them to a new position (3-D...

Replication Variance Estimation under Two-phase Sampling in the Presence of Non-response

Directory of Open Access Journals (Sweden)

Muqaddas Javed

2014-09-01

Full Text Available Kim and Yu (2011 discussed replication variance estimator for two-phase stratified sampling. In this paper estimators for mean have been proposed in two-phase stratified sampling for different situation of existence of non-response at first phase and second phase. The expressions of variances of these estimators have been derived. Furthermore, replication-based jackknife variance estimators of these variances have also been derived. Simulation study has been conducted to investigate the performance of the suggested estimators.

Phase-mapping technique for the evaluation of aortic valve stenosis by MR

International Nuclear Information System (INIS)

Engels, G.; Mueller, E.; Reynen, K.; Wilke, N.; Bachmann, K.

1992-01-01

New MR-techniques for quantitative blood flow registration such as phase-mapping (a two-dimensional space-resolved technique with a time-averaged measurement of blood flow) or RACE (real-time acquisition and evaluation of blood flow in one-dimensional space projection) are available for the diagnosis of valvular heart disease. Initial results of grading aortic valve stenosis by these methods are shown in comparison to continuous wave Ultrasound-Doppler. Two groups of 15 patients were examined by RACE or phase-mapping, 12 respectively 8 of whom suffered from an aortic valve stenosis. The shape of blood flow profiles as well as grading of aortic valve stenosis show high concordance when comparing the results of MR and Doppler technique. Good reliability and practicability of the demonstrated MR-method are shown. With respect to the results of RACE and phase-mapping the development of an alternative and competing MR-method for the evaluation of valvular heart disease and shunt diagnostics seems possible. (orig.)

Phase-mapping technique for the evaluation of aortic valve stenosis by MR

Energy Technology Data Exchange (ETDEWEB)

Engels, G. [Medizinische Klinik 2, Univ. of Erlangen (Germany); Mueller, E. [Siemens Medical Engineering Group, Erlangen (Germany); Reynen, K. [Medizinische Klinik 2, Univ. of Erlangen (Germany); Wilke, N. [Siemens Medical Engineering Group, Erlangen (Germany); Bachmann, K. [Medizinische Klinik 2, Univ. of Erlangen (Germany)

1992-08-01

New MR-techniques for quantitative blood flow registration such as phase-mapping (a two-dimensional space-resolved technique with a time-averaged measurement of blood flow) or RACE (real-time acquisition and evaluation of blood flow in one-dimensional space projection) are available for the diagnosis of valvular heart disease. Initial results of grading aortic valve stenosis by these methods are shown in comparison to continuous wave Ultrasound-Doppler. Two groups of 15 patients were examined by RACE or phase-mapping, 12 respectively 8 of whom suffered from an aortic valve stenosis. The shape of blood flow profiles as well as grading of aortic valve stenosis show high concordance when comparing the results of MR and Doppler technique. Good reliability and practicability of the demonstrated MR-method are shown. With respect to the results of RACE and phase-mapping the development of an alternative and competing MR-method for the evaluation of valvular heart disease and shunt diagnostics seems possible. (orig.)

Determination of phase transitions in a lyotropic liquid crystal by Positron Annihilation technique

International Nuclear Information System (INIS)

Castillo V, V.M.

1994-01-01

Positron annihilation technique was used to determine the phase transitions in a lyotropic liquid crystal, as a function of temperature. Seven different concentrations of the surfactant cetyldimethylethylammonium bromide, were studied. The liquid crystal studied consisted of a binary system, formed by the surfactant and water. Positron annihilation technique has a very high sensitivity toward changes in the microestructure, in condensed matter, this is useful in order to detect the temperatures at which phase transitions occur and the number of these, in a liquid crystalline system. Thus, phase transitions are related with changes occurred in the ortho-positronium parameters: lifetime (τ 3 ) and intensity of formation (I 3 ). Six different kinds of phases were detected in the system studied in a temperature range of 35 to 140 Centigrade degrees, those phases were: hexagonal, hexagonal-lamellae, lamellae, lamellae-cubic, nematic and anisotropic. Using optical microscopic the textures of these phases were assigned. (Author)

Key-space analysis of double random phase encryption technique

Science.gov (United States)

Monaghan, David S.; Gopinathan, Unnikrishnan; Naughton, Thomas J.; Sheridan, John T.

2007-09-01

We perform a numerical analysis on the double random phase encryption/decryption technique. The key-space of an encryption technique is the set of possible keys that can be used to encode data using that technique. In the case of a strong encryption scheme, many keys must be tried in any brute-force attack on that technique. Traditionally, designers of optical image encryption systems demonstrate only how a small number of arbitrary keys cannot decrypt a chosen encrypted image in their system. However, this type of demonstration does not discuss the properties of the key-space nor refute the feasibility of an efficient brute-force attack. To clarify these issues we present a key-space analysis of the technique. For a range of problem instances we plot the distribution of decryption errors in the key-space indicating the lack of feasibility of a simple brute-force attack.

Methodological integrative review of the work sampling technique used in nursing workload research.

Science.gov (United States)

Blay, Nicole; Duffield, Christine M; Gallagher, Robyn; Roche, Michael

2014-11-01

To critically review the work sampling technique used in nursing workload research. Work sampling is a technique frequently used by researchers and managers to explore and measure nursing activities. However, work sampling methods used are diverse making comparisons of results between studies difficult. Methodological integrative review. Four electronic databases were systematically searched for peer-reviewed articles published between 2002-2012. Manual scanning of reference lists and Rich Site Summary feeds from contemporary nursing journals were other sources of data. Articles published in the English language between 2002-2012 reporting on research which used work sampling to examine nursing workload. Eighteen articles were reviewed. The review identified that the work sampling technique lacks a standardized approach, which may have an impact on the sharing or comparison of results. Specific areas needing a shared understanding included the training of observers and subjects who self-report, standardization of the techniques used to assess observer inter-rater reliability, sampling methods and reporting of outcomes. Work sampling is a technique that can be used to explore the many facets of nursing work. Standardized reporting measures would enable greater comparison between studies and contribute to knowledge more effectively. Author suggestions for the reporting of results may act as guidelines for researchers considering work sampling as a research method. © 2014 John Wiley & Sons Ltd.

Method optimization for non-equilibrium solid phase microextraction sampling of HAPs for GC/MS analysis

Science.gov (United States)

Zawadowicz, M. A.; Del Negro, L. A.

2010-12-01

Hazardous air pollutants (HAPs) are usually present in the atmosphere at pptv-level, requiring measurements with high sensitivity and minimal contamination. Commonly used evacuated canister methods require an overhead in space, money and time that often is prohibitive to primarily-undergraduate institutions. This study optimized an analytical method based on solid-phase microextraction (SPME) of ambient gaseous matrix, which is a cost-effective technique of selective VOC extraction, accessible to an unskilled undergraduate. Several approaches to SPME extraction and sample analysis were characterized and several extraction parameters optimized. Extraction time, temperature and laminar air flow velocity around the fiber were optimized to give highest signal and efficiency. Direct, dynamic extraction of benzene from a moving air stream produced better precision (±10%) than sampling of stagnant air collected in a polymeric bag (±24%). Using a low-polarity chromatographic column in place of a standard (5%-Phenyl)-methylpolysiloxane phase decreased the benzene detection limit from 2 ppbv to 100 pptv. The developed method is simple and fast, requiring 15-20 minutes per extraction and analysis. It will be field-validated and used as a field laboratory component of various undergraduate Chemistry and Environmental Studies courses.

Solid Phase Characterization of Tank 241-C-105 Grab Samples

International Nuclear Information System (INIS)

Ely, T. M.; LaMothe, M. E.; Lachut, J. S.

2016-01-01

The solid phase characterization (SPC) of three grab samples from single-shell Tank 241-C-105 (C-105) that were received at the laboratory the week of October 26, 2015, has been completed. The three samples were received and broken down in the 11A hot cells.

Performance Evaluation of Eleven-Phase Induction Machine with Different PWM Techniques

Directory of Open Access Journals (Sweden)

M.I. Masoud

2015-06-01

Full Text Available Multiphase induction machines are used extensively in low and medium voltage (MV drives. In MV drives, power switches have a limitation associated with switching frequency. This paper is a comparative study of the eleven-phase induction machine’s performance when used as a prototype and fed sinusoidal pulse-width-modulation (SPWM with a low switching frequency, selective harmonic elimination (SHE, and single pulse modulation (SPM techniques. The comparison depends on voltage/frequency controls for the same phase of voltage applied on the machine terminals for all previous techniques. The comparative study covers torque ripple, stator and harmonic currents, and motor efficiency.

Visualization and automatic detection of defect distribution in GaN atomic structure from sampling Moiré phase.

Science.gov (United States)

Wang, Qinghua; Ri, Shien; Tsuda, Hiroshi; Kodera, Masako; Suguro, Kyoichi; Miyashita, Naoto

2017-09-19

Quantitative detection of defects in atomic structures is of great significance to evaluating product quality and exploring quality improvement process. In this study, a Fourier transform filtered sampling Moire technique was proposed to visualize and detect defects in atomic arrays in a large field of view. Defect distributions, defect numbers and defect densities could be visually and quantitatively determined from a single atomic structure image at low cost. The effectiveness of the proposed technique was verified from numerical simulations. As an application, the dislocation distributions in a GaN/AlGaN atomic structure in two directions were magnified and displayed in Moire phase maps, and defect locations and densities were detected automatically. The proposed technique is able to provide valuable references to material scientists and engineers by checking the effect of various treatments for defect reduction. © 2017 IOP Publishing Ltd.

Optimization of cloud point extraction and solid phase extraction methods for speciation of arsenic in natural water using multivariate technique.

Science.gov (United States)

Baig, Jameel A; Kazi, Tasneem G; Shah, Abdul Q; Arain, Mohammad B; Afridi, Hassan I; Kandhro, Ghulam A; Khan, Sumaira

2009-09-28

The simple and rapid pre-concentration techniques viz. cloud point extraction (CPE) and solid phase extraction (SPE) were applied for the determination of As(3+) and total inorganic arsenic (iAs) in surface and ground water samples. The As(3+) was formed complex with ammonium pyrrolidinedithiocarbamate (APDC) and extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114, after centrifugation the surfactant-rich phase was diluted with 0.1 mol L(-1) HNO(3) in methanol. While total iAs in water samples was adsorbed on titanium dioxide (TiO(2)); after centrifugation, the solid phase was prepared to be slurry for determination. The extracted As species were determined by electrothermal atomic absorption spectrometry. The multivariate strategy was applied to estimate the optimum values of experimental factors for the recovery of As(3+) and total iAs by CPE and SPE. The standard addition method was used to validate the optimized methods. The obtained result showed sufficient recoveries for As(3+) and iAs (>98.0%). The concentration factor in both cases was found to be 40.

Crystalline phases by an improved gradient expansion technique

Science.gov (United States)

Carignano, S.; Mannarelli, M.; Anzuini, F.; Benhar, O.

2018-02-01

We develop an innovative technique for studying inhomogeneous phases with a spontaneous broken symmetry. The method relies on the knowledge of the exact form of the free energy in the homogeneous phase and on a specific gradient expansion of the order parameter. We apply this method to quark matter at vanishing temperature and large chemical potential, which is expected to be relevant for astrophysical considerations. The method is remarkably reliable and fast as compared to performing the full numerical diagonalization of the quark Hamiltonian in momentum space and is designed to improve the standard Ginzburg-Landau expansion close to the phase transition points. For definiteness, we focus on inhomogeneous chiral symmetry breaking, accurately reproducing known results for one-dimensional and two-dimensional modulations and examining novel crystalline structures, as well. Consistently with previous results, we find that the energetically favored modulation is the so-called one-dimensional real-kink crystal. We propose a qualitative description of the pairing mechanism to motivate this result.

RF Sub-sampling Receiver Architecture based on Milieu Adapting Techniques

DEFF Research Database (Denmark)

Behjou, Nastaran; Larsen, Torben; Jensen, Ole Kiel

2012-01-01

A novel sub-sampling based architecture is proposed which has the ability of reducing the problem of image distortion and improving the signal to noise ratio significantly. The technique is based on sensing the environment and adapting the sampling rate of the receiver to the best possible...

Improved importance sampling technique for efficient simulation of digital communication systems

Science.gov (United States)

Lu, Dingqing; Yao, Kung

1988-01-01

A new, improved importance sampling (IIS) approach to simulation is considered. Some basic concepts of IS are introduced, and detailed evolutions of simulation estimation variances for Monte Carlo (MC) and IS simulations are given. The general results obtained from these evolutions are applied to the specific previously known conventional importance sampling (CIS) technique and the new IIS technique. The derivation for a linear system with no signal random memory is considered in some detail. For the CIS technique, the optimum input scaling parameter is found, while for the IIS technique, the optimum translation parameter is found. The results are generalized to a linear system with memory and signals. Specific numerical and simulation results are given which show the advantages of CIS over MC and IIS over CIS for simulations of digital communications systems.

Cone penetrometer tests and HydroPunch sampling: A screening technique for plume definition

International Nuclear Information System (INIS)

Smolley, M.; Kappmeyer, J.C.

1991-01-01

Cone penetrometer tests and HydroPunch sampling were used to define the extent of volatile organic compounds in ground water. The investigation indicated that the combination of the these techniques is effective for obtaining ground water samples for preliminary plume definition. HydroPunch samples can be collected in unconsolidated sediments and the analytical results obtained from these samples are comparable to those obtained from adjacent monitoring wells. This sampling method is a rapid and cost-effective screening technique for characterizing the extent of contaminant plumes in soft sediment environments. Use of this screening technique allowed monitoring wells to be located at the plume boundary, thereby reducing the number of wells installed and the overall cost of the plume definition program

Single-particle characterization of ice-nucleating particles and ice particles residuals sampled by three different techniques

Science.gov (United States)

Kandler, Konrad; Worringen, Annette; Benker, Nathalie; Dirsch, Thomas; Mertes, Stephan; Schenk, Ludwig; Kästner, Udo; Frank, Fabian; Nillius, Björn; Bundke, Ulrich; Rose, Diana; Curtius, Joachim; Kupiszewski, Piotr; Weingartner, Ernest; Vochezer, Paul; Schneider, Johannes; Schmidt, Susan; Weinbruch, Stephan; Ebert, Martin

2015-04-01

During January/February 2013, at the High Alpine Research Station Jungfraujoch a measurement campaign was carried out, which was centered on atmospheric ice-nucleating particles (INP) and ice particle residuals (IPR). Three different techniques for separation of INP and IPR from the non-ice-active particles are compared. The Ice Selective Inlet (ISI) and the Ice Counterflow Virtual Impactor (Ice-CVI) sample ice particles from mixed phase clouds and allow for the analysis of the residuals. The combination of the Fast Ice Nucleus Chamber (FINCH) and the Ice Nuclei Pumped Counterflow Virtual Impactor (IN-PCVI) provides ice-activating conditions to aerosol particles and extracts the activated INP for analysis. Collected particles were analyzed by scanning electron microscopy and energy-dispersive X-ray microanalysis to determine size, chemical composition and mixing state. All INP/IPR-separating techniques had considerable abundances (median 20 - 70 %) of instrumental contamination artifacts (ISI: Si-O spheres, probably calibration aerosol; Ice-CVI: Al-O particles; FINCH+IN-PCVI: steel particles). Also, potential sampling artifacts (e.g., pure soluble material) occurred with a median abundance of separated by all three techniques. Soot was a minor contributor. Lead was detected in less than 10 % of the particles, of which the majority were internal mixtures with other particle types. Sea-salt and sulfates were identified by all three methods as INP/IPR. Most samples showed a maximum of the INP/IPR size distribution at 400 nm geometric diameter. In a few cases, a second super-micron maximum was identified. Soot/carbonaceous material and metal oxides were present mainly in the submicron range. ISI and FINCH yielded silicates and Ca-rich particles mainly with diameters above 1 µm, while the Ice-CVI also separated many submicron IPR. As strictly parallel sampling could not be performed, a part of the discrepancies between the different techniques may result from

Solid phase microextraction.

Science.gov (United States)

Pawliszyn, J

2001-01-01

Solid Phase Microextraction (SPME) uses a small volume of sorbent dispersed typically on the surface of small fibres, to isolate and concentrate analytes from sample matrix. After contact with sample, analytes are absorbed or adsorbed by the fibre phase (depending on the nature of the coating) until an equilibrium is reached in the system. The amount of an analyte extracted by the coating at equilibrium is determined by the magnitude of the partition coefficient of the analyte between the sample matrix and the coating material. After the extraction step, the fibres are transferred, with the help of a syringe-like handling device, to analytical instrument, for separation and quantitation of target analytes. This technique integrates sampling, extraction and sample introduction and is a simple way of facilitating on-site monitoring. Applications of this technique include environmental monitoring, industrial hygiene, process monitoring, clinical, forensic, food, flavour, fragrance and drug analyses, in laboratory and on-site analysis.

Chance constrained problems: penalty reformulation and performance of sample approximation technique

Czech Academy of Sciences Publication Activity Database

Branda, Martin

2012-01-01

Roč. 48, č. 1 (2012), s. 105-122 ISSN 0023-5954 R&D Projects: GA ČR(CZ) GBP402/12/G097 Institutional research plan: CEZ:AV0Z10750506 Keywords : chance constrained problems * penalty functions * asymptotic equivalence * sample approximation technique * investment problem Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.619, year: 2012 http://library.utia.cas.cz/separaty/2012/E/branda-chance constrained problems penalty reformulation and performance of sample approximation technique.pdf

X-ray phase-contrast imaging

Science.gov (United States)

Endrizzi, Marco

2018-01-01

X-ray imaging is a standard tool for the non-destructive inspection of the internal structure of samples. It finds application in a vast diversity of fields: medicine, biology, many engineering disciplines, palaeontology and earth sciences are just few examples. The fundamental principle underpinning the image formation have remained the same for over a century: the X-rays traversing the sample are subjected to different amount of absorption in different parts of the sample. By means of phase-sensitive techniques it is possible to generate contrast also in relation to the phase shifts imparted by the sample and to extend the capabilities of X-ray imaging to those details that lack enough absorption contrast to be visualised in conventional radiography. A general overview of X-ray phase contrast imaging techniques is presented in this review, along with more recent advances in this fast evolving field and some examples of applications.

Sampling methods and non-destructive examination techniques for large radioactive waste packages

International Nuclear Information System (INIS)

Green, T.H.; Smith, D.L.; Burgoyne, K.E.; Maxwell, D.J.; Norris, G.H.; Billington, D.M.; Pipe, R.G.; Smith, J.E.; Inman, C.M.

1992-01-01

Progress is reported on work undertaken to evaluate quality checking methods for radioactive wastes. A sampling rig was designed, fabricated and used to develop techniques for the destructive sampling of cemented simulant waste using remotely operated equipment. An engineered system for the containment of cooling water was designed and manufactured and successfully demonstrated with the drum and coring equipment mounted in both vertical and horizontal orientations. The preferred in-cell orientation was found to be with the drum and coring machinery mounted in a horizontal position. Small powdered samples can be taken from cemented homogeneous waste cores using a hollow drill/vacuum section technique with the preferred subsampling technique being to discard the outer 10 mm layer to obtain a representative sample of the cement core. Cement blends can be dissolved using fusion techniques and the resulting solutions are stable to gelling for periods in excess of one year. Although hydrochloric acid and nitric acid are promising solvents for dissolution of cement blends, the resultant solutions tend to form silicic acid gels. An estimate of the beta-emitter content of cemented waste packages can be obtained by a combination of non-destructive and destructive techniques. The errors will probably be in excess of +/-60 % at the 95 % confidence level. Real-time X-ray video-imaging techniques have been used to analyse drums of uncompressed, hand-compressed, in-drum compacted and high-force compacted (i.e. supercompacted) simulant waste. The results have confirmed the applicability of this technique for NDT of low-level waste. 8 refs., 12 figs., 3 tabs

State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review.

Science.gov (United States)

Berton, Paula; Lana, Nerina B; Ríos, Juan M; García-Reyes, Juan F; Altamirano, Jorgelina C

2016-01-28

Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

An advanced ultrasonic technique for slow and void fraction measurements of two-phase flow

International Nuclear Information System (INIS)

Faccini, J.L.H.; Su, J.; Harvel, G.D.; Chang, J.S.

2004-01-01

In this paper, we present a hybrid type counterpropagating transmission ultrasonic technique (CPTU) for flow and time averaging ultrasonic transmission intensity void fraction measurements (TATIU) of air-water two-phase flow, which is tested in the new two-phase flow test section mounted recently onto an existing single phase flow rig. The circular pipe test section is made of 51.2 mm stainless steel, followed by a transparent extruded acrylic pipe aimed at flow visualization. The two-phase flow rig operates in several flow regimes: bubbly, smooth stratified, wavy stratified and slug flow. The observed flow patterns are compared with previous experimental and numerical flow regime map for horizontal two phase flows. These flow patterns will be identified by time averaging transmission intensity ultrasonic techniques which have been developed to meet this particular application. A counterpropagating transmission ultrasonic flowmeter is used to measure the flow rate of liquid phase. A pulse-echo TATIU ultrasonic technique used to measure the void fraction of the horizontal test section is presented. We can draw the following conclusions: 1) the ultrasonic system was able to characterize the 2 flow patterns simulated (stratified and plug flow); 2) the results obtained for water volumetric fraction require more experimental work to determine exactly the technique uncertainties but, a priori, they are consistent with earlier work; and 3) the experimental uncertainties can be reduced by improving the data acquisition system, changing the acquisition time interval from seconds to milliseconds

A Comparison of Soil-Water Sampling Techniques

Science.gov (United States)

Tindall, J. A.; Figueroa-Johnson, M.; Friedel, M. J.

2007-12-01

The representativeness of soil pore water extracted by suction lysimeters in ground-water monitoring studies is a problem that often confounds interpretation of measured data. Current soil water sampling techniques cannot identify the soil volume from which a pore water sample is extracted, neither macroscopic, microscopic, or preferential flowpath. This research was undertaken to compare values of extracted suction lysimeters samples from intact soil cores with samples obtained by the direct extraction methods to determine what portion of soil pore water is sampled by each method. Intact soil cores (30 centimeter (cm) diameter by 40 cm height) were extracted from two different sites - a sandy soil near Altamonte Springs, Florida and a clayey soil near Centralia in Boone County, Missouri. Isotopically labeled water (O18? - analyzed by mass spectrometry) and bromide concentrations (KBr- - measured using ion chromatography) from water samples taken by suction lysimeters was compared with samples obtained by direct extraction methods of centrifugation and azeotropic distillation. Water samples collected by direct extraction were about 0.25 ? more negative (depleted) than that collected by suction lysimeter values from a sandy soil and about 2-7 ? more negative from a well structured clayey soil. Results indicate that the majority of soil water in well-structured soil is strongly bound to soil grain surfaces and is not easily sampled by suction lysimeters. In cases where a sufficient volume of water has passed through the soil profile and displaced previous pore water, suction lysimeters will collect a representative sample of soil pore water from the sampled depth interval. It is suggested that for stable isotope studies monitoring precipitation and soil water, suction lysimeter should be installed at shallow depths (10 cm). Samples should also be coordinated with precipitation events. The data also indicate that each extraction method be use to sample a different

Can groundwater sampling techniques used in monitoring wells influence methane concentrations and isotopes?

Science.gov (United States)

Rivard, Christine; Bordeleau, Geneviève; Lavoie, Denis; Lefebvre, René; Malet, Xavier

2018-03-06

Methane concentrations and isotopic composition in groundwater are the focus of a growing number of studies. However, concerns are often expressed regarding the integrity of samples, as methane is very volatile and may partially exsolve during sample lifting in the well and transfer to sampling containers. While issues concerning bottle-filling techniques have already been documented, this paper documents a comparison of methane concentration and isotopic composition obtained with three devices commonly used to retrieve water samples from dedicated observation wells. This work lies within the framework of a larger project carried out in the Saint-Édouard area (southern Québec, Canada), whose objective was to assess the risk to shallow groundwater quality related to potential shale gas exploitation. The selected sampling devices, which were tested on ten wells during three sampling campaigns, consist of an impeller pump, a bladder pump, and disposable sampling bags (HydraSleeve). The sampling bags were used both before and after pumping, to verify the appropriateness of a no-purge approach, compared to the low-flow approach involving pumping until stabilization of field physicochemical parameters. Results show that methane concentrations obtained with the selected sampling techniques are usually similar and that there is no systematic bias related to a specific technique. Nonetheless, concentrations can sometimes vary quite significantly (up to 3.5 times) for a given well and sampling event. Methane isotopic composition obtained with all sampling techniques is very similar, except in some cases where sampling bags were used before pumping (no-purge approach), in wells where multiple groundwater sources enter the borehole.

Comprehensive analysis of TEM methods for LiFePO4/FePO4 phase mapping: spectroscopic techniques (EFTEM, STEM-EELS) and STEM diffraction techniques (ACOM-TEM).

Science.gov (United States)

Mu, X; Kobler, A; Wang, D; Chakravadhanula, V S K; Schlabach, S; Szabó, D V; Norby, P; Kübel, C

2016-11-01

Transmission electron microscopy (TEM) has been used intensively in investigating battery materials, e.g. to obtain phase maps of partially (dis)charged (lithium) iron phosphate (LFP/FP), which is one of the most promising cathode material for next generation lithium ion (Li-ion) batteries. Due to the weak interaction between Li atoms and fast electrons, mapping of the Li distribution is not straightforward. In this work, we revisited the issue of TEM measurements of Li distribution maps for LFP/FP. Different TEM techniques, including spectroscopic techniques (energy filtered (EF)TEM in the energy range from low-loss to core-loss) and a STEM diffraction technique (automated crystal orientation mapping (ACOM)), were applied to map the lithiation of the same location in the same sample. This enabled a direct comparison of the results. The maps obtained by all methods showed excellent agreement with each other. Because of the strong difference in the imaging mechanisms, it proves the reliability of both the spectroscopic and STEM diffraction phase mapping. A comprehensive comparison of all methods is given in terms of information content, dose level, acquisition time and signal quality. The latter three are crucial for the design of in-situ experiments with beam sensitive Li-ion battery materials. Furthermore, we demonstrated the power of STEM diffraction (ACOM-STEM) providing additional crystallographic information, which can be analyzed to gain a deeper understanding of the LFP/FP interface properties such as statistical information on phase boundary orientation and misorientation between domains. Copyright © 2016 Elsevier B.V. All rights reserved.

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

DEFF Research Database (Denmark)

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

2001-01-01

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

Significance of phase-display technique for diagnosis of WPW-Syndrome

International Nuclear Information System (INIS)

Mester, J.; Mate, E.; Marosi, G.; Csernay, L.

1985-01-01

28 patients with WPW-syndrome were investigated by nuclear cardiology. Phase-display techniques were capable of visualizing and localizing ventricular preexcitations. The prematurely contraction ventricle was diagnosed in 81% of the cases concordant to the results of 12-channel ECG-technique. The control group consisted of 13 LGL-patients and revealed 3 false positives resulting in a specificity of 77%. The results were checked with respect to reproducibility. Additional projections increased the sensitivity of the method. (orig.) [de

An on-line push/pull perfusion-based hollow-fiber liquid-phase microextraction system for high-performance liquid chromatographic determination of alkylphenols in water samples.

Science.gov (United States)

Chao, Yu-Ying; Jian, Zhi-Xuan; Tu, Yi-Ming; Wang, Hsaio-Wen; Huang, Yeou-Lih

2013-06-07

In this study, we employed a novel on-line method, push/pull perfusion hollow-fiber liquid-phase microextraction (PPP-HF-LPME), to extract 4-tert-butylphenol, 2,4-di-tert-butylphenol, 4-n-nonylphenol, and 4-n-octylphenol from river and tap water samples; we then separated and quantified the extracted analytes through high-performance liquid chromatography (HPLC). Using this approach, we overcame the problem of fluid loss across the porous HF membrane to the donor phase, permitting on-line coupling of HF-LPME to HPLC. In our PPP-HF-LPME system, we used a push/pull syringe pump as the driving source to perfuse the acceptor phase, while employing a heating mantle and an ultrasonic probe to accelerate mass transfer. We optimized the experimental conditions such as the nature of the HF supported intermediary phase and the acceptor phase, the composition of the donor and acceptor phases, the sample temperature, and the sonication conditions. Our proposed method provided relative standard deviations of 3.1-6.2%, coefficients of determination (r(2)) of 0.9989-0.9998, and limits of detection of 0.03-0.2 ng mL(-1) for the analytes under the optimized conditions. When we applied this method to analyses of river and tap water samples, our results confirmed that this microextraction technique allows reliable monitoring of alkylphenols in water samples.

Development of environmental sample analysis techniques for safeguards

International Nuclear Information System (INIS)

Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka

1999-01-01

JAERI has been developing environmental sample analysis techniques for safeguards and preparing a clean chemistry laboratory with clean rooms. Methods to be developed are a bulk analysis and a particle analysis. In the bulk analysis, Inductively-Coupled Plasma Mass Spectrometer or Thermal Ionization Mass Spectrometer are used to measure nuclear materials after chemical treatment of sample. In the particle analysis, Electron Probe Micro Analyzer and Secondary Ion Mass Spectrometer are used for elemental analysis and isotopic analysis, respectively. The design of the clean chemistry laboratory has been carried out and construction will be completed by the end of March, 2001. (author)

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

DEFF Research Database (Denmark)

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

2002-01-01

In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From the measure...... the measurements we derive the small-signal alpha-parameter and the time-dependent chirp for different operation conditions.......In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From...

Monitoring well design and sampling techniques at NAPL sites

International Nuclear Information System (INIS)

Collins, M.; Rohrman, W.R.; Drake, K.D.

1992-01-01

The existence of Non-Aqueous Phase Liquids (NAPLs) at many Superfund and RCRA hazardous waste sites has become a recognized problem in recent years. The large number of sites exhibiting this problem results from the fact that many of the most frequently used industrial solvents and petroleum products can exist as NAPLs. Hazardous waste constituents occurring as NAPLs possess a common characteristic that causes great concern during groundwater contamination evaluation: while solubility in water is generally very low, it is sufficient to cause groundwater to exceed Maximum Contamination Levels (MCLs). Thus, even a small quantity of NAPL within a groundwater regime can act as a point source with the ability to contaminate vast quantities of groundwater over time. This property makes it imperative that groundwater investigations focus heavily on characterizing the nature, extent, and migration pathways of NAPLs at sites where it exists. Two types of NAPLs may exist in a groundwater system. Water-immiscible liquid constituents having a specific gravity greater than one are termed Dense Non-Aqueous Phase Liquids, while those with a specific gravity less than one are considered Light Non-Aqueous Phase Liquids. For a groundwater investigation to properly characterize the two types of NAPLs, careful consideration must be given to the placement and sampling of groundwater monitoring wells. Unfortunately, technical reviewers at EPA Region VII and the Corps of Engineers find that many groundwater investigations fall short in characterizing NAPLs because several basic considerations were overlooked. Included among these are monitoring well location and screen placement with respect to the water table and significant confining units, and the ability of the well sampling method to obtain samples of NAPL. Depending on the specific gravity of the NAPL that occurs at a site, various considerations can substantially enhance adequate characterization of NAPL contaminants

Application of ultrasonic phased array technique for inspection of stud bolts in nuclear reactor vessel

International Nuclear Information System (INIS)

Choi, Sang Woo; Lee, Joon Ho; Park, Min Su; Cho, Youn Ho; Park, Moon Ho

2004-01-01

The stud bolt is one of crucial parts for safety of reactor vessels in nuclear power plants. Cracks 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 take too much time to inspect stud bolt by using conventional ultrasonic technique. In addition, there were numerous spurious signal reflected from every thread. In this study, the advanced ultrasonic phased array technique was introduced for inspect stud bolts. The phased array technique provide fast inspection and high detectability of defects. There are sector scanning and linear scanning method in phased array technique, and these scanning methods were applied to inspect stud bolt and detectability was investigated.

Measurement of specimen-induced aberrations of biological samples using phase stepping interferometry.

Science.gov (United States)

Schwertner, M; Booth, M J; Neil, M A A; Wilson, T

2004-01-01

Confocal or multiphoton microscopes, which deliver optical sections and three-dimensional (3D) images of thick specimens, are widely used in biology. These techniques, however, are sensitive to aberrations that may originate from the refractive index structure of the specimen itself. The aberrations cause reduced signal intensity and the 3D resolution of the instrument is compromised. It has been suggested to correct for aberrations in confocal microscopes using adaptive optics. In order to define the design specifications for such adaptive optics systems, one has to know the amount of aberrations present for typical applications such as with biological samples. We have built a phase stepping interferometer microscope that directly measures the aberration of the wavefront. The modal content of the wavefront is extracted by employing Zernike mode decomposition. Results for typical biological specimens are presented. It was found for all samples investigated that higher order Zernike modes give only a small contribution to the overall aberration. Therefore, these higher order modes can be neglected in future adaptive optics sensing and correction schemes implemented into confocal or multiphoton microscopes, leading to more efficient designs.

Standardization of proton-induced x-ray emission technique for analysis of thick samples

Science.gov (United States)

Ali, Shad; Zeb, Johar; Ahad, Abdul; Ahmad, Ishfaq; Haneef, M.; Akbar, Jehan

2015-09-01

This paper describes the standardization of the proton-induced x-ray emission (PIXE) technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials (SRMs) were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 MeV obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.

Chromium speciation in environmental samples using a solid phase spectrophotometric method

Science.gov (United States)

Amin, Alaa S.; Kassem, Mohammed A.

2012-10-01

A solid phase extraction technique is proposed for preconcentration and speciation of chromium in natural waters using spectrophotometric analysis. The procedure is based on sorption of chromium(III) as 4-(2-benzothiazolylazo)2,2'-biphenyldiol complex on dextran-type anion-exchange gel (Sephadex DEAE A-25). After reduction of Cr(VI) by 0.5 ml of 96% concentrated H2SO4 and ethanol, the system was applied to the total chromium. The concentration of Cr(VI) was calculated as the difference between the total Cr and the Cr(III) content. The influences of some analytical parameters such as: pH of the aqueous solution, amounts of 4-(2-benzothiazolylazo)2,2'-biphenyldiol (BTABD), and sample volumes were investigated. The absorbance of the gel, at 628 and 750 nm, packed in a 1.0 mm cell, is measured directly. The molar absorptivities were found to be 2.11 × 107 and 3.90 × 107 L mol-1 cm-1 for 500 and 1000 ml, respectively. Calibration is linear over the range 0.05-1.45 μg L-1 with RSD of <1.85% (n = 8.0). Using 35 mg exchanger, the detection and quantification limits were 13 and 44 ng L-1 for 500 ml sample, whereas for 1000 ml sample were 8.0 and 27 ng L-1, respectively. Increasing the sample volume can enhance the sensitivity. No considerable interferences have been observed from other investigated anions and cations on the chromium speciation. The proposed method was applied to the speciation of chromium in natural waters and total chromium preconcentration in microwave digested tobacco, coffee, tea, and soil samples. The results were simultaneously compared with those obtained using an ET AAS method, whereby the validity of the method has been tested.

Hybrid vapor phase-solution phase growth techniques for improved CZT(S,Se) photovoltaic device performance

Energy Technology Data Exchange (ETDEWEB)

Chang, Liang-Yi; Gershon, Talia S.; Haight, Richard A.; Lee, Yun Seog

2016-12-27

A hybrid vapor phase-solution phase CZT(S,Se) growth technique is provided. In one aspect, a method of forming a kesterite absorber material on a substrate includes the steps of: depositing a layer of a first kesterite material on the substrate using a vapor phase deposition process, wherein the first kesterite material includes Cu, Zn, Sn, and at least one of S and Se; annealing the first kesterite material to crystallize the first kesterite material; and depositing a layer of a second kesterite material on a side of the first kesterite material opposite the substrate using a solution phase deposition process, wherein the second kesterite material includes Cu, Zn, Sn, and at least one of S and Se, wherein the first kesterite material and the second kesterite material form a multi-layer stack of the absorber material on the substrate. A photovoltaic device and method of formation thereof are also provided.

Studies on Pt–Mo phases using analytical techniques with high resolution

Energy Technology Data Exchange (ETDEWEB)

Topic, M., E-mail: mtopic@tlabs.ac.za [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Khumalo, Z. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); University of Cape Town, Physics Department, Private Bag X3, Rondebosch 7701 (South Africa); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, CPUT, Belville (South Africa)

2014-01-01

Pt–Mo coated system annealed at 1050 °C for 24 h was investigated using several analytical techniques with high resolution (SEM/EDX, μ-PIXE, RBS and XRD). These techniques provide structural and compositional data throughout the material depth and probing area. The results depend on the applied beam, its energy and size. They contribute to a better understanding of thermal annealing effects on the solid-state phase transformation and morphological changes in Pt–Mo coatings. The results indicate the presence of Pt- and Mo-solid solutions and two Pt–Mo phases (PtMo and Pt{sub 2}Mo{sub 3}), changes in the coating morphology, such as increased surface roughness and formation of “lace morphology”, as well as an increase in coating thickness.

Uranium-233 analysis of biological samples

International Nuclear Information System (INIS)

Gies, R.A.; Ballou, J.E.; Case, A.C.

1979-01-01

Two liquid scintillation techniques were compared for 233 U analysis: a two-phase extraction system (D2EHPA) developed by Keough and Powers, 1970, for Pu analysis; and a single-phase emulsion system (TT21) that holds the total sample in suspension with the scintillator. The first system (D2EHPA) was superior in reducing background (two- to threefold) and in accommodating a larger sample volume (fivefold). Samples containing > 50 mg/ml of slats were not extracted quantitatively by D2EHPA

Laboratory techniques for safe encapsulation of α-emitting powder samples

International Nuclear Information System (INIS)

Chamberlain, H.E.; Pottinger, J.S.

1984-01-01

Plutonium oxide powder samples can be encapsulated in thin plastic film to prevent spread of contamination in counting and X-ray diffraction equipment. The film has to be thin enough to transmit X-rays and α-particles. Techniques are described for the wrapping process and the precautions necessary to keep the sample processing line free of significant contamination. (author)

The digital geometric phase technique applied to the deformation evaluation of MEMS devices

International Nuclear Information System (INIS)

Liu, Z W; Xie, H M; Gu, C Z; Meng, Y G

2009-01-01

Quantitative evaluation of the structure deformation of microfabricated electromechanical systems is of importance for the design and functional control of microsystems. In this investigation, a novel digital geometric phase technique was developed to meet the deformation evaluation requirement of microelectromechanical systems (MEMS). The technique is performed on the basis of regular artificial lattices, instead of a natural atom lattice. The regular artificial lattices with a pitch ranging from micrometer to nanometer will be directly fabricated on the measured surface of MEMS devices by using a focused ion beam (FIB). Phase information can be obtained from the Bragg filtered images after fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) of the scanning electronic microscope (SEM) images. Then the in-plane displacement field and the local strain field related to the phase information will be evaluated. The obtained results show that the technique can be well applied to deformation measurement with nanometer sensitivity and stiction force estimation of a MEMS device

Multi-Phase Sub-Sampling Fractional-N PLL with soft loop switching for fast robust locking

NARCIS (Netherlands)

Liao, Dongyi; Dai, FA Foster; Nauta, Bram; Klumperink, Eric A.M.

2017-01-01

This paper presents a low phase noise sub-sampling PLL (SSPLL) with multi-phase outputs. Automatic soft switching between the sub-sampling phase loop and frequency loop is proposed to improve robustness against perturbations and interferences that may cause a traditional SSPLL to lose lock. A

Solid phase extraction for the speciation and preconcentration of inorganic selenium in water samples: a review.

Science.gov (United States)

Herrero Latorre, C; Barciela García, J; García Martín, S; Peña Crecente, R M

2013-12-04

Selenium is an essential element for the normal cellular function of living organisms. However, selenium is toxic at concentrations of only three to five times higher than the essential concentration. The inorganic forms (mainly selenite and selenate) present in environmental water generally exhibit higher toxicity (up to 40 times) than organic forms. Therefore, the determination of low levels of different inorganic selenium species in water is an analytical challenge. Solid-phase extraction has been used as a separation and/or preconcentration technique prior to the determination of selenium species due to the need for accurate measurements for Se species in water at extremely low levels. The present paper provides a critical review of the published methods for inorganic selenium speciation in water samples using solid phase extraction as a preconcentration procedure. On the basis of more than 75 references, the different speciation strategies used for this task have been highlighted and classified. The solid-phase extraction sorbents and the performance and analytical characteristics of the developed methods for Se speciation are also discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Calculation of sample problems related to two-phase flow blowdown transients in pressure relief piping of a PWR pressurizer

International Nuclear Information System (INIS)

Shin, Y.W.; Wiedermann, A.H.

1984-02-01

A method was published, based on the integral method of characteristics, by which the junction and boundary conditions needed in computation of a flow in a piping network can be accurately formulated. The method for the junction and boundary conditions formulation together with the two-step Lax-Wendroff scheme are used in a computer program; the program in turn, is used here in calculating sample problems related to the blowdown transient of a two-phase flow in the piping network downstream of a PWR pressurizer. Independent, nearly exact analytical solutions also are obtained for the sample problems. Comparison of the results obtained by the hybrid numerical technique with the analytical solutions showed generally good agreement. The good numerical accuracy shown by the results of our scheme suggest that the hybrid numerical technique is suitable for both benchmark and design calculations of PWR pressurizer blowdown transients

Application of the ultrasonic phased array technique to alloy 182 weld inspection in PWR

International Nuclear Information System (INIS)

Hsiao, Chu Chung; Shie, Namg Chian; Chu, Shyr Liang; Lee, Sou See; Toung, Jean Chung; Su, Liang Chun; Yang, Hai Ming

2006-01-01

Cracks were found in nickel-based welds frequently in some nuclear power plants. The development of inspection technique capability of finding these cracks is thus in great demand. The difficulties of inspection and evaluation for nickel-based welds include ultrasonic reflection of interface of dissimilar materials, ultrasonic distortion of anisotropic microstructure, and signal-to-noise ratio reduction of coarse grain. In this study, an Alloy 182 mock-up with the same size and material properties as in the field is designed and fabricated. The Alloy 182 mock-up specimen contains various cracks and notches for calibration. Phased array UT and other ultrasonic inspection techniques are used in this study. Based on the experiment results, the phased array probe with 2D dual crystals and low frequency (1.5MHz) longitudinal wave is found to perform well. Finally, phased array ultrasonic testing technique has been approved to be an effectively nondestructive test method for DMW with real size testing block involved. Typically, phased array probe can generate sharp tip diffraction signal and thus reliable and accurate result can be obtained for sizing the defect. Furthermore, phased array probe can also generate various angles and focal lengths and thus combinatorial effect can be achieved for several traditional probes. With a full understanding of the beam behavior and an optimized delay laws, the phased away ultrasonic technique integrated with an automatic scanner will achieve not only to save scanning time but also to reduce the amount of radiation exposure on field inspection.

Current trends in sample preparation for cosmetic analysis.

Science.gov (United States)

Zhong, Zhixiong; Li, Gongke

2017-01-01

The widespread applications of cosmetics in modern life make their analysis particularly important from a safety point of view. There is a wide variety of restricted ingredients and prohibited substances that primarily influence the safety of cosmetics. Sample preparation for cosmetic analysis is a crucial step as the complex matrices may seriously interfere with the determination of target analytes. In this review, some new developments (2010-2016) in sample preparation techniques for cosmetic analysis, including liquid-phase microextraction, solid-phase microextraction, matrix solid-phase dispersion, pressurized liquid extraction, cloud point extraction, ultrasound-assisted extraction, and microwave digestion, are presented. Furthermore, the research and progress in sample preparation techniques and their applications in the separation and purification of allowed ingredients and prohibited substances are reviewed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent advances in column switching sample preparation in bioanalysis.

Science.gov (United States)

Kataoka, Hiroyuki; Saito, Keita

2012-04-01

Column switching techniques, using two or more stationary phase columns, are useful for trace enrichment and online automated sample preparation. Target fractions from the first column are transferred online to a second column with different properties for further separation. Column switching techniques can be used to determine the analytes in a complex matrix by direct sample injection or by simple sample treatment. Online column switching sample preparation is usually performed in combination with HPLC or capillary electrophoresis. SPE or turbulent flow chromatography using a cartridge column and in-tube solid-phase microextraction using a capillary column have been developed for convenient column switching sample preparation. Furthermore, various micro-/nano-sample preparation devices using new polymer-coating materials have been developed to improve extraction efficiency. This review describes current developments and future trends in novel column switching sample preparation in bioanalysis, focusing on innovative column switching techniques using new extraction devices and materials.

105-F and DR Phase 1 Sampling and Analysis Plan

International Nuclear Information System (INIS)

Curry, L.R.

1998-06-01

This SAP presents the rationale and strategy for characterization of specific rooms within the 105-F and 105-DR reactor buildings. Figures 1-1 and 1-2 identify the rooms that are the subject of this SAP. These rooms are to be decontaminated and demolished as an initial step (Phase 1 ) in the Interim Safe Storage process for these reactors. Section 1.0 presents the background and sites history for the reactor buildings and summarizes the data quality objective process, which provides the logical basis for this SAP. Preliminary surveys indicate that little radiochemical contamination is present. Section 2.0 presents the quality assurance project plan, which includes a project management structure, sampling methods and quality control, and oversight of the sampling process. Section 2.2.1 summarizes the sampling methods, reflecting the radiological and chemical sampling designs presented in Tables 1-17 and 1-18. Section 3.0 presents the Field Sampling Plan for Phase 1. The sampling design is broken into two stages. Stage 1 will verify the list of radioactive constituents of concern and generate the isotopic distribution. The objectives of Stage 2 are to estimate the radionuclide inventories of room debris, quantify chemical contamination, and survey room contents for potential salvage or recycle. Table 3-1 presents the sampling activities to be performed in Stage 1. Tables 1-17 and 1-18 identify samples to be collected in Stage 2. Stage 2 will consist primarily of survey data collection, with fixed laboratory samples to be collected in areas showing visible stains. Quality control sampling requirements are presented in Table 3-2

Sensitivity studies on the multi-sensor conductivity probe measurement technique for two-phase flows

Energy Technology Data Exchange (ETDEWEB)

Worosz, Ted [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Bernard, Matt [The United States Nuclear Regulatory Commission, 11545 Rockville Pike, Rockville, MD 20852 (United States); Kong, Ran; Toptan, Aysenur [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Kim, Seungjin, E-mail: skim@psu.edu [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Hoxie, Chris [The United States Nuclear Regulatory Commission, 11545 Rockville Pike, Rockville, MD 20852 (United States)

2016-12-15

Highlights: • Revised conductivity probe circuit to eliminate signal “ghosting” among sensors. • Higher sampling frequencies suggested for bubble number frequency and a{sub i} measurements. • Two-phase parameter sensitivity to measurement duration and bubble number investigated. • Sensors parallel to pipe wall recommended for symmetric bubble velocity measurements. • Sensor separation distance ratio (s/d) greater than four minimizes bubble velocity error. - Abstract: The objective of this study is to advance the local multi-sensor conductivity probe measurement technique through systematic investigation into several practical aspects of a conductivity probe measurement system. Firstly, signal “ghosting” among probe sensors is found to cause artificially high bubble velocity measurements and low interfacial area concentration (a{sub i}) measurements that depend on sampling frequency and sensor impedance. A revised electrical circuit is suggested to eliminate this artificial variability. Secondly, the sensitivity of the probe measurements to sampling frequency is investigated in 13 two-phase flow conditions with superficial liquid and gas velocities ranging from 1.00–5.00 m/s and 0.17–2.0 m/s, respectively. With increasing gas flow rate, higher sampling frequencies, greater than 100 kHz in some cases, are required to adequately capture the bubble number frequency and a{sub i} measurements. This trend is due to the increase in gas velocity and the transition to the slug flow regime. Thirdly, the sensitivity of the probe measurements to the measurement duration as well as the sample number is investigated for the same flow conditions. Measurements of both group-I (spherical/distorted) and group-II (cap/slug/churn-turbulent) bubbles are found to be relatively insensitive to both the measurement duration and the number of bubbles, as long as the measurements are made for a duration long enough to capture a collection of samples characteristic to a

Eddy current techniques for super duplex stainless steel characterization

Energy Technology Data Exchange (ETDEWEB)

Camerini, C., E-mail: cgcamerini@metalmat.ufrj.br [Laboratory of Non-Destructive Testing, Corrosion and Welding, Department of Metallurgical and Materials Engineering, Federal University of Rio de Janeiro (Brazil); Sacramento, R.; Areiza, M.C.; Rocha, A. [Laboratory of Non-Destructive Testing, Corrosion and Welding, Department of Metallurgical and Materials Engineering, Federal University of Rio de Janeiro (Brazil); Santos, R. [PETROBRAS R& D Center, Rio de Janeiro (Brazil); Rebello, J.M.; Pereira, G. [Laboratory of Non-Destructive Testing, Corrosion and Welding, Department of Metallurgical and Materials Engineering, Federal University of Rio de Janeiro (Brazil)

2015-08-15

Super duplex stainless steel (SDSS) is a two-phase material where the microstructure consists of grains of ferrite (δ) and austenite (γ). SDSS exhibit an attractive combination of properties, such as: strength, toughness and stress corrosion cracking resistance. Nevertheless, SDSS attain these properties after a controlled solution heat treatment, leading to a similar volumetric fraction of δ and γ. Any further heat treatment, welding operation for example, can change the balance of the original phases, or may also lead to precipitation of a deleterious phase, such as sigma (σ). For these situations, the material corrosion resistance is severely impaired. In the present study, several SDSS samples with low σ phase content and non-balanced microstructure were intentionally obtained by thermally treating SDSS specimens. Electromagnetic techniques, conventional Eddy Current Testing (ECT) and Saturated Low Frequency Eddy Current (SLOFEC), were employed to characterize the SDSS samples. The results showed that ECT and SLOFEC are reliable techniques to evaluate σ phase presence in SDSS and can provide an estimation of the δ content. - Highlights: • Sigma phase precipitation, even for low amounts, dramatically affects SDSS properties. • SDSS samples were thermally treated and carefully characterized by X-Ray Diffraction. • NDT techniques detected low amounts of sigma phase in SDSS microstructure.

Eddy current techniques for super duplex stainless steel characterization

International Nuclear Information System (INIS)

Camerini, C.; Sacramento, R.; Areiza, M.C.; Rocha, A.; Santos, R.; Rebello, J.M.; Pereira, G.

2015-01-01

Super duplex stainless steel (SDSS) is a two-phase material where the microstructure consists of grains of ferrite (δ) and austenite (γ). SDSS exhibit an attractive combination of properties, such as: strength, toughness and stress corrosion cracking resistance. Nevertheless, SDSS attain these properties after a controlled solution heat treatment, leading to a similar volumetric fraction of δ and γ. Any further heat treatment, welding operation for example, can change the balance of the original phases, or may also lead to precipitation of a deleterious phase, such as sigma (σ). For these situations, the material corrosion resistance is severely impaired. In the present study, several SDSS samples with low σ phase content and non-balanced microstructure were intentionally obtained by thermally treating SDSS specimens. Electromagnetic techniques, conventional Eddy Current Testing (ECT) and Saturated Low Frequency Eddy Current (SLOFEC), were employed to characterize the SDSS samples. The results showed that ECT and SLOFEC are reliable techniques to evaluate σ phase presence in SDSS and can provide an estimation of the δ content. - Highlights: • Sigma phase precipitation, even for low amounts, dramatically affects SDSS properties. • SDSS samples were thermally treated and carefully characterized by X-Ray Diffraction. • NDT techniques detected low amounts of sigma phase in SDSS microstructure

Innovative directional and position specific sampling technique. Phase 3: Final report, July 1992--September 1994

International Nuclear Information System (INIS)

Hutzel, W.J.; Hill, J.L. III; Foster, E.L.

1994-09-01

The POLO System is a major enhancement to the state of the art for subsurface environmental restoration equipment. The system locate s the tip position of penetrometer probes as they are placed underground while meeting the rigid constraints of environmental restoration applications. POLO is applicable to small diameter probes, does not obstruct the center of the probe, is rugged, is unaffected by the presence of steel or other magnetic material, and is capable of remote operation beneath underground tanks or foundations. The development and adaptation of the POLO System for use with penetrometers has progressed through three development phases prior to commercialization. Phases I and II of the contract included the design, testing, and integration of all components of the POLO device. Efforts were made to simulate field conditions in terms of the scale of the components as well as the operating environment. The preestablished success criterion, which has been maintained throughout the research, was to demonstrate path tracking with a total error of less than 0.50% of the distance traveled for distances less than 70 meters. The results tests on individual POLO components showed that the equipment met or exceeded the success criterion. Phase II laboratory scale path tracking experiments also met the success criterion. Phase III moved the POLO System into the field. The full-scale field demonstration tested the ability of the new POLO Module to track the path of a small diameter probe as it moved underground

Comparison of the solid-phase extraction efficiency of a bounded and an included cyclodextrin-silica microporous composite for polycyclic aromatic hydrocarbons determination in water samples.

Science.gov (United States)

Mauri-Aucejo, Adela; Amorós, Pedro; Moragues, Alaina; Guillem, Carmen; Belenguer-Sapiña, Carolina

2016-08-15

Solid-phase extraction is one of the most important techniques for sample purification and concentration. A wide variety of solid phases have been used for sample preparation over time. In this work, the efficiency of a new kind of solid-phase extraction adsorbent, which is a microporous material made from modified cyclodextrin bounded to a silica network, is evaluated through an analytical method which combines solid-phase extraction with high-performance liquid chromatography to determine polycyclic aromatic hydrocarbons in water samples. Several parameters that affected the analytes recovery, such as the amount of solid phase, the nature and volume of the eluent or the sample volume and concentration influence have been evaluated. The experimental results indicate that the material possesses adsorption ability to the tested polycyclic aromatic hydrocarbons. Under the optimum conditions, the quantification limits of the method were in the range of 0.09-2.4μgL(-1) and fine linear correlations between peak height and concentration were found around 1.3-70μgL(-1). The method has good repeatability and reproducibility, with coefficients of variation under 8%. Due to the concentration results, this material may represent an alternative for trace analysis of polycyclic aromatic hydrocarbons in water trough solid-phase extraction. Copyright © 2016 Elsevier B.V. All rights reserved.

Phase quantification of mullite-zirconia and zircon commercial powders using PAC and XRD techniques

Energy Technology Data Exchange (ETDEWEB)

Rendtorff, Nicolas M.; Conconi, Maria S.; Aglietti, Esteban F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC: CONICET-CIC) (Argentina); Chain, Cecilia Y.; Pasquevich, Alberto F. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rivas, Patricia C. [CONICET (Argentina); Martinez, Jorge A., E-mail: toto@fisica.unlp.edu.ar; Caracoche, Maria C. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina)

2010-06-15

The short range technique of the Perturbed Angular Correlation (PAC) and x-ray diffraction (Rietveld) methods have been employed to determine the phase content in commercial mullite-zirconia and zircon raw materials that are ordinarily used to produce ceramic materials. The PAC technique, which probes zirconium-containing compounds at nanoscopic level, showed that zircon contains crystalline ZrSiO{sub 4} and an important amount of a structurally distorted zircon, which is also observed accompanying monoclinic zirconia in mullite-zirconia. This particular zircon phase was not detected by the long range x-ray diffraction-Rietveld technique. After an annealing treatment, important changes in crystalline contents of the powders allow confirming, by the x-ray diffraction-Rietveld method, the preexistence of this particular zircon phase. This fact must be taken into account when preparing multicomposites based on the present raw materials.

Assessment of Natural Radioactivity in TENORM Samples Using Different Techniques

International Nuclear Information System (INIS)

Salman, Kh.A.; Shahein, A.Y.

2009-01-01

In petroleum oil industries, technologically-enhanced, naturally occurring radioactive materials are produced. The presence of TENORM constitutes a significant radiological human health hazard. In the present work, liquid scintillation counting technique was used to determine both 222 Rn and 226 Ra concentrations in TENORM samples, by measuring 222 Rn concentrations in the sample at different intervals of time after preparation. The radiation doses from the TENORM samples were estimated using thermoluminenscent detector (TLD-4000). The estimated radiation doses were found to be proportional to both the measured radiation doses in site and natural activity concentration in the samples that measured with LSC

Photothermal experiments on condensed phase samples of agricultural interest : optical and thermal characterization

OpenAIRE

Favier, J.P.

1997-01-01

A rapidly increasing number of photothermal (PT) techniques has had a considerable impact on agriculture and environmental sciences in the last decade. It was the purpose of the work described here to develop and apply new PT techniques in this specific field of research.

Chapter I is a general introduction with an overview of PT techniques used in this research. Two different photoacoustic (PA) techniques used for optical characterization of a variety of condensed phase sa...

Cleaning and Cleanliness Verification Techniques for Mars Returned Sample Handling

Science.gov (United States)

Mickelson, E. T.; Lindstrom, D. J.; Allton, J. H.; Hittle, J. D.

2002-01-01

Precision cleaning and cleanliness verification techniques are examined as a subset of a comprehensive contamination control strategy for a Mars sample return mission. Additional information is contained in the original extended abstract.

An alternative phase-space distribution to sample initial conditions for classical dynamics simulations

International Nuclear Information System (INIS)

Garcia-Vela, A.

2002-01-01

A new quantum-type phase-space distribution is proposed in order to sample initial conditions for classical trajectory simulations. The phase-space distribution is obtained as the modulus of a quantum phase-space state of the system, defined as the direct product of the coordinate and momentum representations of the quantum initial state. The distribution is tested by sampling initial conditions which reproduce the initial state of the Ar-HCl cluster prepared by ultraviolet excitation, and by simulating the photodissociation dynamics by classical trajectories. The results are compared with those of a wave packet calculation, and with a classical simulation using an initial phase-space distribution recently suggested. A better agreement is found between the classical and the quantum predictions with the present phase-space distribution, as compared with the previous one. This improvement is attributed to the fact that the phase-space distribution propagated classically in this work resembles more closely the shape of the wave packet propagated quantum mechanically

Structure analysis of turbulent liquid phase by POD and LSE techniques

International Nuclear Information System (INIS)

Munir, S.; Muthuvalu, M. S.; Siddiqui, M. I.; Heikal, M. R.; Aziz, A. Rashid A.

2014-01-01

In this paper, vortical structures and turbulence characteristics of liquid phase in both single liquid phase and two-phase slug flow in pipes were studied. Two dimensional velocity vector fields of liquid phase were obtained by Particle image velocimetry (PIV). Two cases were considered one single phase liquid flow at 80 l/m and second slug flow by introducing gas at 60 l/m while keeping liquid flow rate same. Proper orthogonal decomposition (POD) and Linear stochastic estimation techniques were used for the extraction of coherent structures and analysis of turbulence in liquid phase for both cases. POD has successfully revealed large energy containing structures. The time dependent POD spatial mode coefficients oscillate with high frequency for high mode numbers. The energy distribution of spatial modes was also achieved. LSE has pointed out the coherent structured for both cases and the reconstructed velocity fields are in well agreement with the instantaneous velocity fields

Structure analysis of turbulent liquid phase by POD and LSE techniques

Energy Technology Data Exchange (ETDEWEB)

Munir, S., E-mail: shahzad-munir@comsats.edu.pk; Muthuvalu, M. S.; Siddiqui, M. I. [Department of Fundamental and Applied Science, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia); Heikal, M. R., E-mail: morgan.heikal@petronas.com.my; Aziz, A. Rashid A., E-mail: morgan.heikal@petronas.com.my [Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)

2014-10-24

In this paper, vortical structures and turbulence characteristics of liquid phase in both single liquid phase and two-phase slug flow in pipes were studied. Two dimensional velocity vector fields of liquid phase were obtained by Particle image velocimetry (PIV). Two cases were considered one single phase liquid flow at 80 l/m and second slug flow by introducing gas at 60 l/m while keeping liquid flow rate same. Proper orthogonal decomposition (POD) and Linear stochastic estimation techniques were used for the extraction of coherent structures and analysis of turbulence in liquid phase for both cases. POD has successfully revealed large energy containing structures. The time dependent POD spatial mode coefficients oscillate with high frequency for high mode numbers. The energy distribution of spatial modes was also achieved. LSE has pointed out the coherent structured for both cases and the reconstructed velocity fields are in well agreement with the instantaneous velocity fields.

Sensor Fusion Techniques for Phased-Array Eddy Current and Phased-Array Ultrasound Data

Energy Technology Data Exchange (ETDEWEB)

Arrowood, Lloyd F. [Y-12 National Security Complex, Oak Ridge, TN (United States)

2018-03-15

Sensor (or Data) fusion is the process of integrating multiple data sources to produce more consistent, accurate and comprehensive information than is provided by a single data source. Sensor fusion may also be used to combine multiple signals from a single modality to improve the performance of a particular inspection technique. Industrial nondestructive testing may utilize multiple sensors to acquire inspection data depending upon the object under inspection and the anticipated types of defects that can be identified. Sensor fusion can be performed at various levels of signal abstraction with each having its strengths and weaknesses. A multimodal data fusion strategy first proposed by Heideklang and Shokouhi that combines spatially scattered detection locations to improve detection performance of surface-breaking and near-surface cracks in ferromagnetic metals is shown using a surface inspection example and is then extended for volumetric inspections. Utilizing data acquired from an Olympus Omniscan MX2 from both phased array eddy current and ultrasound probes on test phantoms, single and multilevel fusion techniques are employed to integrate signals from the two modalities. Preliminary results demonstrate how confidence in defect identification and interpretation benefit from sensor fusion techniques. Lastly, techniques for integrating data into radiographic and volumetric imagery from computed tomography are described and results are presented.

Elemental analyses of goundwater: demonstrated advantage of low-flow sampling and trace-metal clean techniques over standard techniques

Science.gov (United States)

Creasey, C. L.; Flegal, A. R.

The combined use of both (1) low-flow purging and sampling and (2) trace-metal clean techniques provides more representative measurements of trace-element concentrations in groundwater than results derived with standard techniques. The use of low-flow purging and sampling provides relatively undisturbed groundwater samples that are more representative of in situ conditions, and the use of trace-element clean techniques limits the inadvertent introduction of contaminants during sampling, storage, and analysis. When these techniques are applied, resultant trace-element concentrations are likely to be markedly lower than results based on standard sampling techniques. In a comparison of data derived from contaminated and control groundwater wells at a site in California, USA, trace-element concentrations from this study were 2-1000 times lower than those determined by the conventional techniques used in sampling of the same wells prior to (5months) and subsequent to (1month) the collections for this study. Specifically, the cadmium and chromium concentrations derived using standard sampling techniques exceed the California Maximum Contaminant Levels (MCL), whereas in this investigation concentrations of both of those elements are substantially below their MCLs. Consequently, the combined use of low-flow and trace-metal clean techniques may preclude erroneous reports of trace-element contamination in groundwater. Résumé L'utilisation simultanée de la purge et de l'échantillonnage à faible débit et des techniques sans traces de métaux permet d'obtenir des mesures de concentrations en éléments en traces dans les eaux souterraines plus représentatives que les résultats fournis par les techniques classiques. L'utilisation de la purge et de l'échantillonnage à faible débit donne des échantillons d'eau souterraine relativement peu perturbés qui sont plus représentatifs des conditions in situ, et le recours aux techniques sans éléments en traces limite l

Development of phased array UT technique for inspection of turbine wheel rim

International Nuclear Information System (INIS)

Komura, I.; Nagal, S.; Goto, M.; Ohmatsu, K.

1986-01-01

A phased array UT technique has been developed for the improvement of defect detection under the keyway region of shrunk-on type turbine wheel. The sector scanning mode operation with plexiglas wedge of phased array capability was applied to construct the B-scope image of turbine wheel rim region. Preceding to the inspection test of the model specimen having real shape of rim region, the distribution of sound field intensity along the steering angle of the scanning line was measured on the test block. Then, the minimum depth of detectable defect by the B-scope imaging was evaluated on the dovetail shape specimens which had different depth EDM notches at the each hook fillet. As the results, it has been realized that the B-scope imaging of the sector scanning mode phased array technique has a capability for distinguishing the defect echoes from the many reflection echoes caused by the complexed shape of wheel rim region

Determination of the fraction of amorphous phases in superconducting samples

International Nuclear Information System (INIS)

Gomes Junior, G.G.; Ogasawara, T.; Amorim, H.S.

2010-01-01

The study phase formation of high critical temperature superconducting (Bi, Pb) - 2223 by partial melting and recrystallization aims to improve the microstructure of the material. Was used for X-ray diffraction characterization of the phases present. The DDM method (Derivative Difference Minimization) was used for the refinement of structures, quantification of the phases and determination the fraction of this amorphous. The advantage this method is not necessary to introduce an internal standard to determine the amorphous fraction. Were observed in the powder precursor phases (Bi, Pb) 2 Sr 2 Ca 2 Cu 3 O x (Bi, Pb) -2223, 93% of the sample, Bi 2 Sr 2 CaCu 2 O y (Bi-2212) and Bi 2 Sr 2 CuO z (Bi-2201). The powder precursor was heat treated at 820-870 deg C. To minimize volatilization of lead, the material was placed in silver crucibles closed. To get a high recovery of (Bi, Pb) - 2223, the material was cooled slowly, due to slow kinetic of formation of this phase. We observed a partial recovery phase (Bi, Pb) -2223. (author)

Development of a solid-phase microextraction-based method for sampling of persistent chlorinated hydrocarbons in an urbanized coastal environment.

Science.gov (United States)

Zeng, Eddy Y; Tsukada, David; Diehl, Dario W

2004-11-01

Solid-phase microextraction (SPME) has been used as an in situ sampling technique for a wide range of volatile organic chemicals, but SPME field sampling of nonvolatile organic pollutants has not been reported. This paper describes the development of an SPME-based sampling method employing a poly(dimethylsiloxane) (PDMS)-coated (100-microm thickness) fiber as the sorbent phase. The laboratory-calibrated PDMS-coated fibers were used to construct SPME samplers, and field tests were conducted at three coastal locations off southern California to determine the equilibrium sampling time and compare the efficacy of the SPME samplers with that of an Infiltrex 100 water pumping system (Axys Environmental Systems Ltd., Sidney, British Columbia, Canada). p,p'-DDE and o,p'-DDE were the components consistently detected in the SPME samples among 42 polychlorinated biphenyl congeners and 17 chlorinated pesticidestargeted. SPME samplers deployed attwo locations with moderate and high levels of contamination for 18 and 30 d, respectively, attained statistically identical concentrations of p,p'-DDE and o,p'-DDE. In addition, SPME samplers deployed for 23 and 43 d, respectively, at a location of low contamination also contained statistically identical concentrations of p,p'-DDE. These results indicate that equilibrium could be reached within 18 to 23 d. The concentrations of p,p'-DDE, o,p'-DDE, or p,p'-DDD obtained with the SPME samplers and the Infiltrex 100 system were virtually identical. In particular, two water column concentration profiles of p,p'-DDE and o,p'-DDE acquired by the SPME samplers at a highly contaminated site on the Palos Verdes Shelf overlapped with the profiles obtained by the Infiltrex 100 system in 1997. The field tests not only reveal the advantages of the SPME samplers compared to the Infiltrex 100 system and other integrative passive devices but also indicate the need to improve the sensitivity of the SPME-based sampling technique.

Analysis of Mars Analogue Soil Samples Using Solid-Phase Microextraction, Organic Solvent Extraction and Gas Chromatography/Mass Spectrometry

Science.gov (United States)

Orzechowska, G. E.; Kidd, R. D.; Foing, B. H.; Kanik, I.; Stoker, C.; Ehrenfreund, P.

2011-01-01

Polycyclic aromatic hydrocarbons (PAHs) are robust and abundant molecules in extraterrestrial environments. They are found ubiquitously in the interstellar medium and have been identified in extracts of meteorites collected on Earth. PAHs are important target molecules for planetary exploration missions that investigate the organic inventory of planets, moons and small bodies. This study is part of an interdisciplinary preparation phase to search for organic molecules and life on Mars. We have investigated PAH compounds in desert soils to determine their composition, distribution and stability. Soil samples (Mars analogue soils) were collected at desert areas of Utah in the vicinity of the Mars Desert Research Station (MDRS), in the Arequipa region in Peru and from the Jutland region of Denmark. The aim of this study was to optimize the solid-phase microextraction (SPME) method for fast screening and determination of PAHs in soil samples. This method minimizes sample handling and preserves the chemical integrity of the sample. Complementary liquid extraction was used to obtain information on five- and six-ring PAH compounds. The measured concentrations of PAHs are, in general, very low, ranging from 1 to 60 ng g(sup -1). The texture of soils is mostly sandy loam with few samples being 100% silt. Collected soils are moderately basic with pH values of 8-9 except for the Salten Skov soil, which is slightly acidic. Although the diverse and variable microbial populations of the samples at the sample sites might have affected the levels and variety of PAHs detected, SPME appears to be a rapid, viable field sampling technique with implications for use on planetary missions.

Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC.

Directory of Open Access Journals (Sweden)

Zachary F Phillips

Full Text Available We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification-an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC, is a single-shot variant of Differential Phase Contrast (DPC, which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps for various in vitro cell samples and c. elegans in a micro-fluidic channel.

THE STUDY OF HEAVY METAL FROM ENVIRONMENTAL SAMPLES BY ATOMIC TECHNIQUES

Directory of Open Access Journals (Sweden)

Ion V. POPESCU

2011-05-01

Full Text Available Using the Atomic Absorption Spectrometry (AAS and Energy Dispersive X-ray spectrometry (EDXRF techniques we analyzed the contents of heavy metals ( Cd, Cr, Ni, Pb, Ti, Sr, Co, Bi from eight wild mushrooms and soil substrate samples (48 samples of eight fungal species and 32 underlying soil samples, collected from ten forest sites of Dambovița County Romania. It was determined that the elements, especially heavy metals, in soil were characteristic of the acidic soils of the Romanian forest lands and are influenced by industrial pollution. Analytical possibilities of AAS and EDXRF analytical techniques have been compared and the heavy metal transfer from substrate to mushrooms has been studied. The coefficient of accumulation of essential and heavy metals has been calculated as well. Heavy metal contents of all analyzed mushrooms were generally higher than previously reported in literature.

Comparison between correlated sampling and the perturbation technique of MCNP5 for fixed-source problems

International Nuclear Information System (INIS)

He Tao; Su Bingjing

2011-01-01

Highlights: → The performance of the MCNP differential operator perturbation technique is compared with that of the MCNP correlated sampling method for three types of fixed-source problems. → In terms of precision, the MCNP perturbation technique outperforms correlated sampling for one type of problem but performs comparably with or even under-performs correlated sampling for the other two types of problems. → In terms of accuracy, the MCNP perturbation calculations may predict inaccurate results for some of the test problems. However, the accuracy can be improved if the midpoint correction technique is used. - Abstract: Correlated sampling and the differential operator perturbation technique are two methods that enable MCNP (Monte Carlo N-Particle) to simulate small response change between an original system and a perturbed system. In this work the performance of the MCNP differential operator perturbation technique is compared with that of the MCNP correlated sampling method for three types of fixed-source problems. In terms of precision of predicted response changes, the MCNP perturbation technique outperforms correlated sampling for the problem involving variation of nuclide concentrations in the same direction but performs comparably with or even underperforms correlated sampling for the other two types of problems that involve void or variation of nuclide concentrations in opposite directions. In terms of accuracy, the MCNP differential operator perturbation calculations may predict inaccurate results that deviate from the benchmarks well beyond their uncertainty ranges for some of the test problems. However, the accuracy of the MCNP differential operator perturbation can be improved if the midpoint correction technique is used.

Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders

Directory of Open Access Journals (Sweden)

Yifeng Yun

2015-03-01

Full Text Available Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED data collection, namely automated diffraction tomography (ADT and rotation electron diffraction (RED, have been developed. Compared with X-ray diffraction (XRD and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni–Se–O–Cl crystals, zeolites, germanates, metal–organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three

Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders.

Science.gov (United States)

Yun, Yifeng; Zou, Xiaodong; Hovmöller, Sven; Wan, Wei

2015-03-01

Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED) data collection, namely automated diffraction tomography (ADT) and rotation electron diffraction (RED), have been developed. Compared with X-ray diffraction (XRD) and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD) provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni-Se-O-Cl crystals, zeolites, germanates, metal-organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional ED methods

X-ray phase radiography and tomography with grating interferometry and the reverse projection technique

International Nuclear Information System (INIS)

Wang, Zhili; Gao, Kun; Ge, Xin; Wu, Zhao; Chen, Heng; Wang, Shenghao; Wu, Ziyu; Zhu, Peiping; Yuan, Qingxi; Huang, Wanxia; Zhang, Kai

2013-01-01

X-ray grating interferometry provides substantially increased contrast over conventional absorption-based imaging methods, and therefore new and complementary information. Compared with other phase-contrast imaging techniques, x-ray grating interferometry can overcome some of the problems that have impaired the applications of x-ray phase-contrast radiography and phase tomography. Recently, special attention has been paid to the development of quantitative phase retrieval methods, which is mandatory to perform x-ray phase tomography, to achieve material identification, to differentiate distinct tissues, etc. Typically, the phase-stepping approach has been utilized for phase retrieval in grating interferometry. This method requires a grating scanning and acquisition of multiple radiographic projections, and therefore is disadvantageous in terms of imaging speed and radiation damage. Here we present an innovative, highly sensitive approach, dubbed ‘reverse projection’ (RP), for quantitative phase retrieval. Compared with the phase-stepping approach, the present RP method abandons grating scanning completely, and thus is advantageous due to its much higher efficiency and the reduced radiation dose, without the degradation of reconstruction quality. This review presents a detailed explanation of the principle of the RP method. Both radiography and phase tomography experiments are performed to validate the RP method. We believe that this new technique will find widespread applications in biomedical imaging and in vivo studies. (paper)

A technique for extracting blood samples from mice in fire toxicity tests

Science.gov (United States)

Bucci, T. J.; Hilado, C. J.; Lopez, M. T.

1976-01-01

The extraction of adequate blood samples from moribund and dead mice has been a problem because of the small quantity of blood in each animal and the short time available between the animals' death and coagulation of the blood. These difficulties are particularly critical in fire toxicity tests because removal of the test animals while observing proper safety precautions for personnel is time-consuming. Techniques for extracting blood samples from mice were evaluated, and a technique was developed to obtain up to 0.8 ml of blood from a single mouse after death. The technique involves rapid exposure and cutting of the posterior vena cava and accumulation of blood in the peritoneal space. Blood samples of 0.5 ml or more from individual mice have been consistently obtained as much as 16 minutes after apparent death. Results of carboxyhemoglobin analyses of blood appeared reproducible and consistent with carbon monoxide concentrations in the exposure chamber.

Source reconstruction using phase space beam summation technique

International Nuclear Information System (INIS)

Graubart, Gideon.

1990-10-01

In this work, the phase-space beam summation technique (PSBS), is applied to back propagation and inverse source problems. The PSBS expresses the field as a superposition of shifted and tilted beams. This phase space spectrum of beams is matched to the source distribution via an amplitude function which expresses the local spectrum of the source function in terms of a local Fourier transform. In this work, the emphasis is on the phase space processing of the data, on the information content of this data and on the back propagation scheme. More work is still required to combine this back propagation approach in a full, multi experiment inverse scattering scheme. It is shown that the phase space distribution of the data, computed via the local spectrum transform, is localized along lines that define the local arrival direction of the wave data. We explore how the choice of the beam width affects the compactification of this distribution, and derive criteria for choosing a window that optimizes this distribution. It should be emphasized that compact distribution implies fewer beams in the back propagation scheme and therefore higher numerical efficiency and better physical insight. Furthermore it is shown how the local information property of the phase space representation can be used to improve the performance of this simple back propagation problem, in particular with regard to axial resolution; the distance to the source can be determined by back propagating only the large angle phase space beams that focus on the source. The information concerning transverse distribution of the source, on the other hand, is contained in the axial phase space region and can therefore be determined by the corresponding back propagating beams. Because of the global nature of the plane waves propagators the conventional plane wave back propagation scheme does not have the same 'focusing' property, and therefore suffers from lack of information localization and axial resolution. The

Comparison of sampling techniques for Rift Valley Fever virus ...

African Journals Online (AJOL)

We investigated mosquito sampling techniques with two types of traps and attractants at different time for trapping potential vectors for Rift Valley Fever virus. The study was conducted in six villages in Ngorongoro district in Tanzania from September to October 2012. A total of 1814 mosquitoes were collected, of which 738 ...

Novel polyamide-based nanofibers prepared by electrospinning technique for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples

Energy Technology Data Exchange (ETDEWEB)

Bagheri, Habib, E-mail: bagheri@sharif.edu [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of); Aghakhani, Ali; Baghernejad, Masoud; Akbarinejad, Alireza [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

2012-02-24

A novel solid phase microextraction (SPME) fiber was fabricated by electrospinning method in which a polymeric solution was converted to nanofibers using high voltages. A thin stainless steel wire was coated by the network of polymeric nanofibers. The polymeric nanofiber coating on the wire was mechanically stable due to the fine and continuous nanofibers formation around the wire with a three dimensional structure. Polyamide (nylon 6), due to its suitable characteristics was used to prepare the unbreakable SPME nanofiber. The scanning electron microscopy (SEM) images of this new coating showed a diameter range of 100-200 nm for polyamide nanofibers with a homogeneous and porous surface structure. The extraction efficiency of new coating was investigated for headspace solid-phase microextraction (HS-SPME) of some environmentally important chlorophenols from aqueous samples followed by gas chromatography-mass spectrometry (GC-MS) analysis. Effect of different parameters influencing the extraction efficiency including extraction temperature, extraction time, ionic strength and polyamide amount were investigated and optimized. In order to improve the chromatographic behavior of phenolic compounds, all the analytes were derivatized prior to the extraction process using basic acetic anhydride. The detection limits of the method under optimized conditions were in the range of 2-10 ng L{sup -1}. The relative standard deviations (RSD) (n = 3) at the concentration level of 1.7-6.7 ng mL{sup -1} were obtained between 1 and 7.4%. The calibration curves of chlorophenols showed linearity in the range of 27-1330 ng L{sup -1} for phenol and monochlorophenols and 7-1000 ng L{sup -1} for dichloro and trichlorophenols. Also, the proposed method was successfully applied to the extraction of phenol and chlorophenols from real water samples and relative recoveries were between 84 and 98% for all the selected analytes except for 2,4,6 tricholophenol which was between 72 and 74%.

Analysis of mineral phases in coal utilizing factor analysis

International Nuclear Information System (INIS)

Roscoe, B.A.; Hopke, P.K.

1982-01-01

The mineral phase inclusions of coal are discussed. The contribution of these to a coal sample are determined utilizing several techniques. Neutron activation analysis in conjunction with coal washability studies have produced some information on the general trends of elemental variation in the mineral phases. These results have been enhanced by the use of various statistical techniques. The target transformation factor analysis is specifically discussed and shown to be able to produce elemental profiles of the mineral phases in coal. A data set consisting of physically fractionated coal samples was generated. These samples were analyzed by neutron activation analysis and then their elemental concentrations examined using TTFA. Information concerning the mineral phases in coal can thus be acquired from factor analysis even with limited data. Additional data may permit the resolution of additional mineral phases as well as refinement of theose already identified

Solid phase radioimmunoassay for quantitation of IgM rheumatoid factor (RF). Comparison with agglutination techniques and radioimmunoprecipitation polyethylene glycol assay (RIPEGA)

Energy Technology Data Exchange (ETDEWEB)

Herrmann, D.; Jaeger, L.; Hein, G.; Henzgen, M.; Fiebig, H.; Schlenvoigt, G.; Vogelsang, H. (Friedrich-Schiller-Universitaet, Jena (German Democratic Republic). Bereich Medizin; Karl-Marx-Universitaet, Leipzig (German Democratic Republic). Sektion Biowissenschaften)

1985-01-01

A solid-phase radioimmunoassay capable of detecting nanogram quantities of human IgM rheumatoid factor using a monoclonal anti-..mu..-chain antibody is described. Human IgG did not interfere with the detection of IgM RF by this method. The small nonspecific binding of nonRF IgM to the human IgG coated tubes utilized in the assay must be corrected for by assaying samples in parallel bovine serum albumin coated control tubes only in cases of deviation of IgM from normal range. 69 coded and randomly arranged sera from patients with rheumatoid arthritis (RA), nonrheumatic joint diseases and healthy adult control subjects were investigated by this method, agglutination techniques as well as RIPEGA. A good correlation between solid-phase radioimmunoassay and agglutination techniques was found. Patients with seropositive RA had significantly higher concentrations of IgM RF than seronegative RA patients or control subjects.

A line-based vegetation sampling technique and its application in ...

African Journals Online (AJOL)

percentage cover, density and intercept frequency) and also provides plant size distributions, yet requires no more sampling effort than the line-intercept method.. A field test of the three techniques in succulent karoo, showed that the discriminating ...

Comparison of correlation analysis techniques for irregularly sampled time series

Directory of Open Access Journals (Sweden)

K. Rehfeld

2011-06-01

Full Text Available Geoscientific measurements often provide time series with irregular time sampling, requiring either data reconstruction (interpolation or sophisticated methods to handle irregular sampling. We compare the linear interpolation technique and different approaches for analyzing the correlation functions and persistence of irregularly sampled time series, as Lomb-Scargle Fourier transformation and kernel-based methods. In a thorough benchmark test we investigate the performance of these techniques.

All methods have comparable root mean square errors (RMSEs for low skewness of the inter-observation time distribution. For high skewness, very irregular data, interpolation bias and RMSE increase strongly. We find a 40 % lower RMSE for the lag-1 autocorrelation function (ACF for the Gaussian kernel method vs. the linear interpolation scheme,in the analysis of highly irregular time series. For the cross correlation function (CCF the RMSE is then lower by 60 %. The application of the Lomb-Scargle technique gave results comparable to the kernel methods for the univariate, but poorer results in the bivariate case. Especially the high-frequency components of the signal, where classical methods show a strong bias in ACF and CCF magnitude, are preserved when using the kernel methods.

We illustrate the performances of interpolation vs. Gaussian kernel method by applying both to paleo-data from four locations, reflecting late Holocene Asian monsoon variability as derived from speleothem δ¹⁸O measurements. Cross correlation results are similar for both methods, which we attribute to the long time scales of the common variability. The persistence time (memory is strongly overestimated when using the standard, interpolation-based, approach. Hence, the Gaussian kernel is a reliable and more robust estimator with significant advantages compared to other techniques and suitable for large scale application to paleo-data.

Application of nuclear and allied techniques for the characterisation of forensic samples

International Nuclear Information System (INIS)

Sudersanan, M.; Kayasth, S.R.; Pant, D.R.; Chattopadhyay, N.; Bhattacharyya, C.N.

2002-01-01

Full text: Forensic science deals with the application of various techniques for physics, chemistry and biology for crime investigation. The legal implication of such analysis put considerable restriction on the choice of analytical techniques. Moreover, the unknown nature of the materials, the limited availability of samples and the large number of elements to be analysed put considerable strain on the analytical chemist on the selection of the appropriate technique. The availability of nuclear techniques has considerably enhanced the scope of forensic analysis. This paper deals with the recent results on the use of nuclear and allied analytical techniques for forensic applications. One of the important types of samples of forensic importance pertain to the identification of gunshot residues. The use of nuclear techniques has considerably simplified the interpretation of results through the use of appropriate elements like Ba, Cu, Sb, Zn, As and Sn etc. The combination of non-nuclear techniques for elements like Pb and Ni which are not easily amenable to be analysed by NAA and the use of appropriate separation procedure has led to the use of this method as a valid and versatile analytical procedure. In view of the presence of a large amounts of extraneous materials like cloth, body tissues etc in these samples and the limited availability of materials, the procedures for sample collection, dissolution and analysis have been standardized. Analysis of unknown materials like powders, metallic pieces etc. for the possible presence of nuclear materials or as materials in illicit trafficking is becoming important in recent years. The use of multi-technique approach is important in this case. Use of non-destructive techniques like XRF and radioactive counting enables the preliminary identification of materials and for the detection of radioactivity. Subsequent analysis by NAA or other appropriate analytical methods allows the characterization of the materials. Such

Study of Defect Sizing in Carbon Steel Butt Welds using Conventional Ultrasonic Technique and Phased Array Ultrasonic

International Nuclear Information System (INIS)

Amry Amin Abas; Noorhazleena Azaman; Mohd Yusnisyam Mohd Yusoff

2016-01-01

Ultrasonic testing is a proven reliable method which is able to detect and measure the size of defects in butt welds with acceptable tolerance. Recent advancement of technology has introduced a computerized technique which is phased array. Phased array employs focal law that enable focusing and steering of beam at the active aperture axis. This enables one line scanning but covering the whole weld volume as compared to conventional technique which employs aster scan and multiple probes to completely cover the whole weld volume. Phased array also gives multiple data view which assist the interpreter. This paper is about the study of these two techniques and technical analysis of comparison between the two. The conventional technique is performed using GE USM GO with 4 MHz 45 degrees shear wave probe. The phased array technique uses OLYMPUS OMNISCAN MX2 with 5L64 linear array probe with 16 elements aperture and 55 degrees wedge emitting shear wave into the specimen. Sensitivity of both techniques are based on 1.5 mm Side Drilled Hole. The results are compared and analysis such as defect sizing and defect type determination are performed. (author)

An XRD technique for quantitative phase analysis of Al-U-Zr alloy

International Nuclear Information System (INIS)

Khan, K.B.; Kulkarni, N.K.; Jain, G.C.

2003-01-01

In several nuclear research reactors all over the world, Al-U alloy is used as fuel. To stabilise less brittle phase UAl 3 in Al-U alloy, a small amount of Zr (1 to 3 wt% ) is added. A rapid, non destructive and simple x-ray diffraction technique has been developed for quantitative phase analysis Al-U-Zr alloy system containing UAl 4 , UAl 3 and Al. (author)

A new sampling technique for surface exposure dating using a portable electric rock cutter

Directory of Open Access Journals (Sweden)

Yusuke Suganuma

2012-07-01

Full Text Available Surface exposure dating using in situ cosmogenic nuclides has contributed to our understanding of Earth-surface processes. The precision of the ages estimated by this method is affected by the sample geometry; therefore, high accuracy measurements of the thickness and shape of the rock sample (thickness and shape is crucial. However, it is sometimes diffi cult to meet these requirements by conventional sampling methods with a hammer and chisel. Here, we propose a new sampling technique using a portable electric rock cutter. This sampling technique is faster, produces more precisely shaped samples, and allows for a more precise age interpretation. A simple theoretical modeldemonstrates that the age error due to defective sample geometry increases as the total sample thickness increases, indicating the importance of precise sampling for surface exposure dating.

Phase 1 sampling and analysis plan for the 304 Concretion Facility closure activities

International Nuclear Information System (INIS)

Adler, J.G.

1994-01-01

This document provides guidance for the initial (Phase 1) sampling and analysis activities associated with the proposed Resource Conservation and Recovery Act of 1976 (RCRA) clean closure of the 304 Concretion Facility. Over its service life, the 304 Concretion Facility housed the pilot plants associated with cladding uranium cores, was used to store engineering equipment and product chemicals, was used to treat low-level radioactive mixed waste, recyclable scrap uranium generated during nuclear fuel fabrication, and uranium-titanium alloy chips, and was used for the repackaging of spent halogenated solvents from the nuclear fuels manufacturing process. The strategy for clean closure of the 304 Concretion Facility is to decontaminate, sample (Phase 1 sampling), and evaluate results. If the evaluation indicates that a limited area requires additional decontamination for clean closure, the limited area will be decontaminated, resampled (Phase 2 sampling), and the result evaluated. If the evaluation indicates that the constituents of concern are below action levels, the facility will be clean closed. Or, if the evaluation indicates that the constituents of concern are present above action levels, the condition of the facility will be evaluated and appropriate action taken. There are a total of 37 sampling locations comprising 12 concrete core, 1 concrete chip, 9 soil, 11 wipe, and 4 asphalt core sampling locations. Analysis for inorganics and volatile organics will be performed on the concrete core and soil samples. Separate concrete core samples will be required for the inorganic and volatile organic analysis (VOA). Analysis for inorganics only will be performed on the concrete chip, wipe, and asphalt samples

Mantle biopsy: a technique for nondestructive tissue-sampling of freshwater mussels

Science.gov (United States)

David J. Berg; Wendell R. Haag; Sheldon I. Guttman; James B. Sickel

1995-01-01

Mantle biopsy is a means of obtaining tissue samples for genetic, physiological, and contaminant studies of bivalves; but the effects of this biopsy on survival have not been determined. We describe a simple technique for obtaining such samples from unionacean bivalves and how we compared survival among biopsied and control organisms in field experiments. Survival was...

A Monte Carlo Sampling Technique for Multi-phonon Processes

Energy Technology Data Exchange (ETDEWEB)

Hoegberg, Thure

1961-12-15

A sampling technique for selecting scattering angle and energy gain in Monte Carlo calculations of neutron thermalization is described. It is supposed that the scattering is separated into processes involving different numbers of phonons. The number of phonons involved is first determined. Scattering angle and energy gain are then chosen by using special properties of the multi-phonon term.

Physical properties of antiferromagnetic Mn doped ZnO samples: Role of impurity phase

Science.gov (United States)

Neogi, S. K.; Karmakar, R.; Misra, A. K.; Banerjee, A.; Das, D.; Bandyopadhyay, S.

2013-11-01

Structural, morphological, optical, and magnetic properties of nanocrystalline Zn1-xMnxO samples (x=0.01, 0.02, 0.04, 0.06, 0.08 and 0.10) prepared by the sol-gel route are studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-visible absorption spectroscopy, Superconducting quantum interference device (SQUID) magnetometry and positron annihilation lifetime spectroscopy (PALS). XRD confirms formation of wurzite structure in all the Mn-substituted samples. A systematic increase in lattice constants and decrease in grain size have been observed with increase in manganese doping concentration up to 6 at% in the ZnO structure. An impurity phase (ZnMnO3) has been detected when percentage of Mn concentration is 6 at% or higher. The optical band gap of the Mn-substituted ZnO samples decrease with increase in doping concentration of manganese whereas the width of the localized states increases. The antiferromagnetic exchange interaction is strong in the samples for 2 and 4 at% of Mn doping but it reduces when the doping level increases from 6 at% and further. Positron life time components τ1 and τ2 are found to decrease when concentration of the dopant exceeds 6 at%. The changes in magnetic properties as well as positron annihilation parameters at higher manganese concentration have been assigned as due to the formation of impurity phase. Single phase structure has been observed up to 6 at% of Mn doping. Impurity phase has been developed above 6 at% of Mn doping. Antiferromagnetic and paramagnetic interactions are present in the samples. Defect parameters show sharp fall as Mn concentration above 6 at%. The magnetic and defect properties are modified by the formation of impurity phase.

Physical properties of antiferromagnetic Mn doped ZnO samples: Role of impurity phase

International Nuclear Information System (INIS)

Neogi, S.K.; Karmakar, R.; Misra, A.K.; Banerjee, A.; Das, D.; Bandyopadhyay, S.

2013-01-01

Structural, morphological, optical, and magnetic properties of nanocrystalline Zn 1−x Mn x O samples (x=0.01, 0.02, 0.04, 0.06, 0.08 and 0.10) prepared by the sol–gel route are studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV–visible absorption spectroscopy, Superconducting quantum interference device (SQUID) magnetometry and positron annihilation lifetime spectroscopy (PALS). XRD confirms formation of wurzite structure in all the Mn-substituted samples. A systematic increase in lattice constants and decrease in grain size have been observed with increase in manganese doping concentration up to 6 at% in the ZnO structure. An impurity phase (ZnMnO 3 ) has been detected when percentage of Mn concentration is 6 at% or higher. The optical band gap of the Mn-substituted ZnO samples decrease with increase in doping concentration of manganese whereas the width of the localized states increases. The antiferromagnetic exchange interaction is strong in the samples for 2 and 4 at% of Mn doping but it reduces when the doping level increases from 6 at% and further. Positron life time components τ 1 and τ 2 are found to decrease when concentration of the dopant exceeds 6 at%. The changes in magnetic properties as well as positron annihilation parameters at higher manganese concentration have been assigned as due to the formation of impurity phase. - highlights: • Single phase structure has been observed up to 6 at% of Mn doping. • Impurity phase has been developed above 6 at% of Mn doping. • Antiferromagnetic and paramagnetic interactions are present in the samples. • Defect parameters show sharp fall as Mn concentration above 6 at%. • The magnetic and defect properties are modified by the formation of impurity phase

Physical properties of antiferromagnetic Mn doped ZnO samples: Role of impurity phase

Energy Technology Data Exchange (ETDEWEB)

Neogi, S.K.; Karmakar, R. [Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009 (India); Misra, A.K. [UGC DAE Consortium for Scientific Research, Salt Lake, Kolkata 700064 (India); Banerjee, A. [Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009 (India); CRNN, University of Calcutta, JD 2, Sector III, Salt Lake, Kolkata 700098 (India); Das, D. [UGC DAE Consortium for Scientific Research, Salt Lake, Kolkata 700064 (India); Bandyopadhyay, S., E-mail: sbaphy@caluniv.ac.in [Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009 (India); CRNN, University of Calcutta, JD 2, Sector III, Salt Lake, Kolkata 700098 (India)

2013-11-15

Structural, morphological, optical, and magnetic properties of nanocrystalline Zn{sub 1−x}Mn{sub x}O samples (x=0.01, 0.02, 0.04, 0.06, 0.08 and 0.10) prepared by the sol–gel route are studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV–visible absorption spectroscopy, Superconducting quantum interference device (SQUID) magnetometry and positron annihilation lifetime spectroscopy (PALS). XRD confirms formation of wurzite structure in all the Mn-substituted samples. A systematic increase in lattice constants and decrease in grain size have been observed with increase in manganese doping concentration up to 6 at% in the ZnO structure. An impurity phase (ZnMnO{sub 3}) has been detected when percentage of Mn concentration is 6 at% or higher. The optical band gap of the Mn-substituted ZnO samples decrease with increase in doping concentration of manganese whereas the width of the localized states increases. The antiferromagnetic exchange interaction is strong in the samples for 2 and 4 at% of Mn doping but it reduces when the doping level increases from 6 at% and further. Positron life time components τ{sub 1} and τ{sub 2} are found to decrease when concentration of the dopant exceeds 6 at%. The changes in magnetic properties as well as positron annihilation parameters at higher manganese concentration have been assigned as due to the formation of impurity phase. - highlights: • Single phase structure has been observed up to 6 at% of Mn doping. • Impurity phase has been developed above 6 at% of Mn doping. • Antiferromagnetic and paramagnetic interactions are present in the samples. • Defect parameters show sharp fall as Mn concentration above 6 at%. • The magnetic and defect properties are modified by the formation of impurity phase.

Cone-shaped membrane liquid phase micro extraction

International Nuclear Information System (INIS)

Hong, Heng See; Sanagi, M.M.; Ibrahim, W.A.W.; Naim, A.A.

2008-01-01

A novel sample pre-treatment technique termed cone-shaped membrane liquid phase micro extraction (CSM-LPME) was developed and combined with micro-liquid chromatography (micro-LC) for the determination of selected pesticides in water samples. Several important extraction parameters such as types of extraction solvent, agitation rate, pH value, total exposure time and effect of salt and humic acids were investigated and optimized. Enrichment factors of >50 folds were easily achieved within 20 min of extraction. The new developed method demonstrated an excellent performance in terms of speed, cost effectiveness, reproducibility, as well as exceptional low detection limits. Current work provides a great interest to further investigate on the applicability of the CSM-LPME technique in analytical chemistry and explores the possibility of replacing conventional extraction techniques such as soxhlet, solid phase extraction (SPE) and solid phase micro extraction (SPME). (author)

Search for Fluid Inclusions in a Carbonaceous Chondrite Using a New X-Ray Micro-Tomography Technique Combined with FIB Sampling

Science.gov (United States)

Tsuchiyama, A.; Miyake, A.; Zolensky, M. E.; Uesugi, K.; Nakano, T.; Takeuchi, A.; Suzuki, Y.; Yoshida, K.

2014-01-01

Early solar system aqueous fluids are preserved in some H chondrites as aqueous fluid inclusions in halite (e.g., [1]). Although potential fluid inclusions are also expected in carbonaceous chondrites [2], they have not been surely confirmed. In order to search for these fluid inclusions, we have developped a new X-ray micro-tomography technique combined with FIB sampling and applied this techniqu to a carbanaceous chondrite. Experimental: A polished thin section of Sutter's Mill meteorite (CM) was observed with an optical microscope and FE-SEM (JEOL 7001F) for chosing mineral grains of carbonates (mainly calcite) and sulfides (FeS and ZnS) 20-50 microns in typical size, which may have aqueous fluid inclusions. Then, a "house" similar to a cube with a roof (20-30 microns in size) is sampled from the mineral grain by using FIB (FEI Quanta 200 3DS). Then, the house was atached to a thin W-needle by FIB and imaged by a SR-based imaging microtomography system with a Fresnel zone plate at beamline BL47XU, SPring-8, Japan. One sample was imaged at two X-ray energies, 7 and 8 keV, to identify mineral phases (dual-enegy microtomography: [3]). The size of voxel (pixel in 3D) was 50-80 nm, which gave the effective spatial resolution of approx. 200 nm. A terrestrial quartz sample with an aqueous fluid inclusion with a bubble was also examined as a test sample by the same method. Results and discussion: A fluid inclusion of 5-8 microns in quartz was clearly identified in a CT image. A bubble of approx. 4 microns was also identified as refraction contrast although the X-ray absorption difference between fluid and bubble is small. Volumes of the fluid and bubble were obtained from the 3D CT images. Fourteen grains of calcite, two grains of iron sulfide and one grain of (Zn,Fe)S were examined. Ten calcite, one iron sulfide and one (Zn,Fe)S grains have inclusions >1 micron in size (the maximum: approx. 5 microns). The shapes are spherical or irregular. Tiny inclusions (tiny solid

Phase distribution measurements in narrow rectangular channels using image processing techniques

International Nuclear Information System (INIS)

Bentley, C.; Ruggles, A.

1991-01-01

Many high flux research reactor fuel assemblies are cooled by systems of parallel narrow rectangular channels. The HFIR is cooled by single phase forced convection under normal operating conditions. However, two-phase forced convection or two phase mixed convection can occur in the fueled region as a result of some hypothetical accidents. Such flow conditions would occur only at decay power levels. The system pressure would be around 0.15 MPa in such circumstances. Phase distribution of air-water flow in a narrow rectangular channel is examined using image processing techniques. Ink is added to the water and clear channel walls are used to allow high speed still photographs and video tape to be taken of the air-water flow field. Flow field images are digitized and stored in a Macintosh 2ci computer using a frame grabber board. Local grey levels are related to liquid thickness in the flow channel using a calibration fixture. Image processing shareware is used to calculate the spatially averaged liquid thickness from the image of the flow field. Time averaged spatial liquid distributions are calculated using image calculation algorithms. The spatially averaged liquid distribution is calculated from the time averaged spatial liquid distribution to formulate the combined temporally and spatially averaged fraction values. The temporally and spatially averaged liquid fractions measured using this technique compare well to those predicted from pressure gradient measurements at zero superficial liquid velocity

Evaluation of primary immunization coverage of infants under universal immunization programme in an urban area of bangalore city using cluster sampling and lot quality assurance sampling techniques.

Science.gov (United States)

K, Punith; K, Lalitha; G, Suman; Bs, Pradeep; Kumar K, Jayanth

2008-07-01

Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. Population-based cross-sectional study. Areas under Mathikere Urban Health Center. Children aged 12 months to 23 months. 220 in cluster sampling, 76 in lot quality assurance sampling. Percentages and Proportions, Chi square Test. (1) Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09%, 14.09% and 1.82%, respectively. With lot quality assurance sampling, it was 92.11%, 6.58% and 1.31%, respectively. (2) Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area.

Phase-coded multi-pulse technique for ultrasonic high-order harmonic imaging of biological tissues in vitro

International Nuclear Information System (INIS)

Ma Qingyu; Zhang Dong; Gong Xiufen; Ma Yong

2007-01-01

Second or higher order harmonic imaging shows significant improvement in image clarity but is degraded by low signal-noise ratio (SNR) compared with fundamental imaging. This paper presents a phase-coded multi-pulse technique to provide the enhancement of SNR for the desired high-order harmonic ultrasonic imaging. In this technique, with N phase-coded pulses excitation, the received Nth harmonic signal is enhanced by 20 log 10 N dB compared with that in the single-pulse mode, whereas the fundamental and other order harmonic components are efficiently suppressed to reduce image confusion. The principle of this technique is theoretically discussed based on the theory of the finite amplitude sound waves, and examined by measurements of the axial and lateral beam profiles as well as the phase shift of the harmonics. In the experimental imaging for two biological tissue specimens, a plane piston source at 2 MHz is used to transmit a sequence of multiple pulses with equidistant phase shift. The second to fifth harmonic images are obtained using this technique with N = 2 to 5, and compared with the images obtained at the fundamental frequency. Results demonstrate that this technique of relying on higher order harmonics seems to provide a better resolution and contrast of ultrasonic images

Single-particle characterization of ice-nucleating particles and ice particle residuals sampled by three different techniques

Science.gov (United States)

Worringen, A.; Kandler, K.; Benker, N.; Dirsch, T.; Mertes, S.; Schenk, L.; Kästner, U.; Frank, F.; Nillius, B.; Bundke, U.; Rose, D.; Curtius, J.; Kupiszewski, P.; Weingartner, E.; Vochezer, P.; Schneider, J.; Schmidt, S.; Weinbruch, S.; Ebert, M.

2015-04-01

In the present work, three different techniques to separate ice-nucleating particles (INPs) as well as ice particle residuals (IPRs) from non-ice-active particles are compared. The Ice Selective Inlet (ISI) and the Ice Counterflow Virtual Impactor (Ice-CVI) sample ice particles from mixed-phase clouds and allow after evaporation in the instrument for the analysis of the residuals. The Fast Ice Nucleus Chamber (FINCH) coupled with the Ice Nuclei Pumped Counterflow Virtual Impactor (IN-PCVI) provides ice-activating conditions to aerosol particles and extracts the activated particles for analysis. The instruments were run during a joint field campaign which took place in January and February 2013 at the High Alpine Research Station Jungfraujoch (Switzerland). INPs and IPRs were analyzed offline by scanning electron microscopy and energy-dispersive X-ray microanalysis to determine their size, chemical composition and mixing state. Online analysis of the size and chemical composition of INP activated in FINCH was performed by laser ablation mass spectrometry. With all three INP/IPR separation techniques high abundances (median 20-70%) of instrumental contamination artifacts were observed (ISI: Si-O spheres, probably calibration aerosol; Ice-CVI: Al-O particles; FINCH + IN-PCVI: steel particles). After removal of the instrumental contamination particles, silicates, Ca-rich particles, carbonaceous material and metal oxides were the major INP/IPR particle types obtained by all three techniques. In addition, considerable amounts (median abundance mostly a few percent) of soluble material (e.g., sea salt, sulfates) were observed. As these soluble particles are often not expected to act as INP/IPR, we consider them as potential measurement artifacts. Minor types of INP/IPR include soot and Pb-bearing particles. The Pb-bearing particles are mainly present as an internal mixture with other particle types. Most samples showed a maximum of the INP/IPR size distribution at 200

TRAN-STAT: statistics for environmental studies, Number 22. Comparison of soil-sampling techniques for plutonium at Rocky Flats

International Nuclear Information System (INIS)

Gilbert, R.O.; Bernhardt, D.E.; Hahn, P.B.

1983-01-01

A summary of a field soil sampling study conducted around the Rocky Flats Colorado plant in May 1977 is preseted. Several different soil sampling techniques that had been used in the area were applied at four different sites. One objective was to comparethe average 239 - 240 Pu concentration values obtained by the various soil sampling techniques used. There was also interest in determining whether there are differences in the reproducibility of the various techniques and how the techniques compared with the proposed EPA technique of sampling to 1 cm depth. Statistically significant differences in average concentrations between the techniques were found. The differences could be largely related to the differences in sampling depth-the primary physical variable between the techniques. The reproducibility of the techniques was evaluated by comparing coefficients of variation. Differences between coefficients of variation were not statistically significant. Average (median) coefficients ranged from 21 to 42 percent for the five sampling techniques. A laboratory study indicated that various sample treatment and particle sizing techniques could increase the concentration of plutonium in the less than 10 micrometer size fraction by up to a factor of about 4 compared to the 2 mm size fraction

Stratified source-sampling techniques for Monte Carlo eigenvalue analysis

International Nuclear Information System (INIS)

Mohamed, A.

1998-01-01

In 1995, at a conference on criticality safety, a special session was devoted to the Monte Carlo ''Eigenvalue of the World'' problem. Argonne presented a paper, at that session, in which the anomalies originally observed in that problem were reproduced in a much simplified model-problem configuration, and removed by a version of stratified source-sampling. In this paper, stratified source-sampling techniques are generalized and applied to three different Eigenvalue of the World configurations which take into account real-world statistical noise sources not included in the model problem, but which differ in the amount of neutronic coupling among the constituents of each configuration. It is concluded that, in Monte Carlo eigenvalue analysis of loosely-coupled arrays, the use of stratified source-sampling reduces the probability of encountering an anomalous result over that if conventional source-sampling methods are used. However, this gain in reliability is substantially less than that observed in the model-problem results

Utility of replica techniques for x-ray microanalysis of second phase particles

International Nuclear Information System (INIS)

Bentley, J.

1984-01-01

X-ray microanalysis of second phase particles in ion-milled or electropolished thin foils is often complicated by the presence of the matrix nearby. Extraction replica techniques provide a means to avoid many of the complications of thin-foil analyses. In this paper, three examples of the analysis of second phase particles are described and illustrate the improvement obtained by the use of extraction replicas for qualitative analysis, quantitative analysis, and analysis of radioactive specimens

Evaluation of primary immunization coverage of infants under universal immunization programme in an urban area of Bangalore city using cluster sampling and lot quality assurance sampling techniques

Directory of Open Access Journals (Sweden)

Punith K

2008-01-01

Full Text Available Research Question: Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? Objective: To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. Study Design: Population-based cross-sectional study. Study Setting: Areas under Mathikere Urban Health Center. Study Subjects: Children aged 12 months to 23 months. Sample Size: 220 in cluster sampling, 76 in lot quality assurance sampling. Statistical Analysis: Percentages and Proportions, Chi square Test. Results: (1 Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09%, 14.09% and 1.82%, respectively. With lot quality assurance sampling, it was 92.11%, 6.58% and 1.31%, respectively. (2 Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area.

Analytical techniques for measurement of 99Tc in environmental samples

International Nuclear Information System (INIS)

Anon.

1979-01-01

Three new methods have been developed for measuring 99 Tc in environmental samples. The most sensitive method is isotope dilution mass spectrometry, which allows measurement of about 1 x 10 -12 grams of 99 Tc. Results on analysis of five samples by this method compare very well with values obtained by a second independent method, which involves counting of beta particles from 99 Tc and internal conversion electrons from /sup 97m/Tc. A third method involving electrothermal atomic absorption has also been developed. Although this method is not as sensitive as the first two techniques, the cost per analysis is expected to be considerably less for certain types of samples

Determination of some trace elements in biological samples using XRF and TXRF techniques

International Nuclear Information System (INIS)

Khuder, A.; Karjou, J.; Sawan, M. K.

2006-07-01

XRF and TXRF techniques were successfully used for the multi-element determination of trace elements in whole blood and human head hair samples. This was achieved by the direct analysis using XRF technique with different collimation units and by the optimized chemical procedures for TXRF analysis. Light element of S and P were preferably determined by XRF with primary x-ray excitation, while, elements of K, Ca, Fe, and Br were determined with a very good accuracy and precision using XRF with Cu- and Mo-secondary targets. The chemical procedure dependent on the preconcentration of trace elements by APDC was superiorly used for the determination of traces of Ni and Pb in the range of 1.0-1.7 μg/dl and 11-23 μg/dl, respectively, in whole blood samples by TXRF technique; determination of other elements as Cu and Zn was also achievable using this approach. Rb in whole blood samples was determined directly after the digestion of samples using PTFE-bomb for TXRF analysis. (author)

Quantitative phase analysis of a highly textured industrial sample using a Rietveld profile analysis

International Nuclear Information System (INIS)

Shin, Eunjoo; Huh, Moo-Young; Seong, Baek-Seok; Lee, Chang-Hee

2001-01-01

For the quantitative phase analysis on highly textured two-phase materials, samples with known weight fractions of zirconium and aluminum were prepared. Strong texture components prevailed in both zirconium and aluminum sheet. The diffraction patterns of samples were measured by the neutron and refined by the Rietveld method. The preferred orientation correction of diffraction patterns was carried out by means of recalculated pole figures from the ODF. The present Rietveld analysis of various samples with different weight fractions showed that the absolute error of the calculated weight fractions was less than 7.1%. (author)

Microextração em fase líquida (LPME: fundamentos da técnica e aplicações na análise de fármacos em fluidos biológicos Liquid-phase microextraction (LPME: fundamentals and applications to the analysis of drugs in biological samples

Directory of Open Access Journals (Sweden)

Anderson Rodrigo Moraes de Oliveira

2008-01-01

Full Text Available The analysis of drugs and metabolites in biological fluids usually requires extraction procedures to achieve sample clean-up and analyte preconcentration. Commonly, extraction procedures are performed using liquid-liquid extraction or solid-phase extraction. Nevertheless, these extraction techniques are considered to be time-consuming and require a large amount of organic solvents. On this basis, microextraction techniques have been developed. Among them, liquid-phase microextraction has been standing out. This review describes the liquid-phase microextraction technique based on hollow fibers as a novel and promising alternative in sample preparation prior to chromatographic or electrophoretic analysis. The basic concepts related to this technique and its applicability in extraction of drugs are discussed.

Mechanical properties of nickel-titanium archwire used in the final treatment phase of Tip-Edge Plus technique: an in vitro study.

Science.gov (United States)

Shen, Xiao; Sun, Xin-hua; Tian, Hua; Zhang, Chun-bo; Yan, Kuo; Guo, Yong-liang

2013-01-01

As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is necessary to evaluate the mechanical properties of the nickel-titanium wire used in the final treatment phase in simulated oral environments to forecast the treatment outcomes. The mechanical properties of 171 thermal nickel-titanium wires of 0.35 mm (0.014-in) in diameters with different deflection of 40 mm in length were investigated with three-point bending test. The samples were divided into 2 groups: as-received and bended groups. In the bended group, samples were divided into 7 subgroups according to the amounts of deflection and named by the canine angulations (-25°, -19°, -13°, -7°, -1°, +5°, +11°). The deflection of wires was made by inserting the wires into the deep tunnel of Tip-Edge Plus brackets positioned in plaster casts with different canine angulations to mimic the use of nickel-titanium wires in the final treatment phase. Immersed the bended group in artificial saliva (pH 6.8) and preserved at 37.0°C. Eight durations of incubation were tested: 1 to 8 weeks. Three analogous samples of each group and subgroups were tested per week. Stiffness (YS:E) and the load-deflection characteristics of unloading plateau section were obtained. Significant changes in specific mechanical properties were observed in long-term immersed and large deflected wires compared with as-received groups. Both immersion time and deflection affected the mechanical properties of wires in the simulated oral environment, and the two factors had synergistic effect. In groups -25°, -19° and -13°, stiffness (YS:E) increased then decreased and average plateau force and ratio of variance decreased then increased correspondingly at specific time. In the final treatment phase of Tip-Edge Plus technique, the mechanical properties of nickel-titanium wire are associated with the

Advanced sampling techniques for hand-held FT-IR instrumentation

Science.gov (United States)

Arnó, Josep; Frunzi, Michael; Weber, Chris; Levy, Dustin

2013-05-01

FT-IR spectroscopy is the technology of choice to identify solid and liquid phase unknown samples. The challenging ConOps in emergency response and military field applications require a significant redesign of the stationary FT-IR bench-top instruments typically used in laboratories. Specifically, field portable units require high levels of resistance against mechanical shock and chemical attack, ease of use in restrictive gear, extreme reliability, quick and easy interpretation of results, and reduced size. In the last 20 years, FT-IR instruments have been re-engineered to fit in small suitcases for field portable use and recently further miniaturized for handheld operation. This article introduces the HazMatID™ Elite, a FT-IR instrument designed to balance the portability advantages of a handheld device with the performance challenges associated with miniaturization. In this paper, special focus will be given to the HazMatID Elite's sampling interfaces optimized to collect and interrogate different types of samples: accumulated material using the on-board ATR press, dispersed powders using the ClearSampler™ tool, and the touch-to-sample sensor for direct liquid sampling. The application of the novel sample swipe accessory (ClearSampler) to collect material from surfaces will be discussed in some detail. The accessory was tested and evaluated for the detection of explosive residues before and after detonation. Experimental results derived from these investigations will be described in an effort to outline the advantages of this technology over existing sampling methods.

Symbol synchronization and sampling frequency synchronization techniques in real-time DDO-OFDM systems

Science.gov (United States)

Chen, Ming; He, Jing; Cao, Zizheng; Tang, Jin; Chen, Lin; Wu, Xian

2014-09-01

In this paper, we propose and experimentally demonstrate a symbol synchronization and sampling frequency synchronization techniques in real-time direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) system, over 100-km standard single mode fiber (SSMF) using a cost-effective directly modulated distributed feedback (DFB) laser. The experiment results show that the proposed symbol synchronization based on training sequence (TS) has a low complexity and high accuracy even at a sampling frequency offset (SFO) of 5000-ppm. Meanwhile, the proposed pilot-assisted sampling frequency synchronization between digital-to-analog converter (DAC) and analog-to-digital converter (ADC) is capable of estimating SFOs with an accuracy of technique can also compensate SFO effects within a small residual SFO caused by deviation of SFO estimation and low-precision or unstable clock source. The two synchronization techniques are suitable for high-speed DDO-OFDM transmission systems.

X-ray Phase Contrast analysis - Digital wavefront development

International Nuclear Information System (INIS)

Idir, Mourad; Potier, Jonathan; Fricker, Sebastien; Snigirev, Anatoly; Snigireva, Irina; Modi, M. H.

2010-01-01

Optical schemes that enable imaging of the phase shift produced by an object have become popular in the x-ray region, where phase can be the dominant contrast mechanism. The propagation-based technique consists of recording the interference pattern produced by choosing one or several sample-to-detector distances. Pioneering studies, carried out making use of synchrotron radiation, demonstrated that this technique results in a dramatic increase of image contrast and detail visibility, allowing the detection of structures invisible with conventional techniques. An experimental and theoretical study of in-line hard x-ray phase-contrast imaging had been performed. The theoretical description of the technique is based on Fresnel diffraction. As an illustration of the potential of this quantitative imaging technique, high-resolution x-ray phase contrast images of simple objects will be presented.

Quantitative phase imaging and differential interference contrast imaging for biological TEM

International Nuclear Information System (INIS)

Allman, B.E.; McMahon, P.J.; Barone-Nugent, E.D.; Nugent, E.D.

2002-01-01

Full text: Phase microscopy is a central technique in science. An experienced microscopist uses this effect to visualise (edge) structure within transparent samples by slightly defocusing the microscope. Although widespread in optical microscopy, phase contrast transmission electron microscopy (TEM) has not been widely adopted. TEM for biological specimens has largely relied on staining techniques to yield sufficient contrast. We show here a simple method for quantitative TEM phase microscopy that quantifies this phase contrast effect. Starting with conventional, digital, bright field images of the sample, our algorithm provides quantitative phase information independent of the sample's bright field intensity image. We present TEM phase images of a range of stained and unstained, biological and material science specimens. This independent phase and intensity information is then used to emulate a range of phase visualisation images familiar to optical microscopy, e.g. differential interference contrast. The phase images contain features not visible with the other imaging modalities. Further, if the TEM samples have been prepared on a microtome to a uniform thickness, the phase information can be converted into refractive index structure of the specimen. Copyright (2002) Australian Society for Electron Microscopy Inc

ANALYSIS OF MONTE CARLO SIMULATION SAMPLING TECHNIQUES ON SMALL SIGNAL STABILITY OF WIND GENERATOR- CONNECTED POWER SYSTEM

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TEMITOPE RAPHAEL AYODELE

2016-04-01

Full Text Available Monte Carlo simulation using Simple Random Sampling (SRS technique is popularly known for its ability to handle complex uncertainty problems. However, to produce a reasonable result, it requires huge sample size. This makes it to be computationally expensive, time consuming and unfit for online power system applications. In this article, the performance of Latin Hypercube Sampling (LHS technique is explored and compared with SRS in term of accuracy, robustness and speed for small signal stability application in a wind generator-connected power system. The analysis is performed using probabilistic techniques via eigenvalue analysis on two standard networks (Single Machine Infinite Bus and IEEE 16–machine 68 bus test system. The accuracy of the two sampling techniques is determined by comparing their different sample sizes with the IDEAL (conventional. The robustness is determined based on a significant variance reduction when the experiment is repeated 100 times with different sample sizes using the two sampling techniques in turn. Some of the results show that sample sizes generated from LHS for small signal stability application produces the same result as that of the IDEAL values starting from 100 sample size. This shows that about 100 sample size of random variable generated using LHS method is good enough to produce reasonable results for practical purpose in small signal stability application. It is also revealed that LHS has the least variance when the experiment is repeated 100 times compared to SRS techniques. This signifies the robustness of LHS over that of SRS techniques. 100 sample size of LHS produces the same result as that of the conventional method consisting of 50000 sample size. The reduced sample size required by LHS gives it computational speed advantage (about six times over the conventional method.

Role of microextraction sampling procedures in forensic toxicology.

Science.gov (United States)

Barroso, Mário; Moreno, Ivo; da Fonseca, Beatriz; Queiroz, João António; Gallardo, Eugenia

2012-07-01

The last two decades have provided analysts with more sensitive technology, enabling scientists from all analytical fields to see what they were not able to see just a few years ago. This increased sensitivity has allowed drug detection at very low concentrations and testing in unconventional samples (e.g., hair, oral fluid and sweat), where despite having low analyte concentrations has also led to a reduction in sample size. Along with this reduction, and as a result of the use of excessive amounts of potentially toxic organic solvents (with the subsequent environmental pollution and costs associated with their proper disposal), there has been a growing tendency to use miniaturized sampling techniques. Those sampling procedures allow reducing organic solvent consumption to a minimum and at the same time provide a rapid, simple and cost-effective approach. In addition, it is possible to get at least some degree of automation when using these techniques, which will enhance sample throughput. Those miniaturized sample preparation techniques may be roughly categorized in solid-phase and liquid-phase microextraction, depending on the nature of the analyte. This paper reviews recently published literature on the use of microextraction sampling procedures, with a special focus on the field of forensic toxicology.

Modified emission-transmission method for determining trace elements in solid samples using the XRF techniques

International Nuclear Information System (INIS)

Poblete, V.; Alvarez, M.; Hermosilla, M.

2000-01-01

This is a study of an analysis of trace elements in medium thick solid samples, by the modified transmission emission method, using the energy dispersion X-ray fluorescence technique (EDXRF). The effects of absorption and reinforcement are the main disadvantages of the EDXRF technique for the quantitative analysis of bigger elements and trace elements in solid samples. The implementation of this method and its application to a variety of samples was carried out using an infinitely thick multi-element white sample that calculates the correction factors by absorbing all the analytes in the sample. The discontinuities in the masic absorption coefficients versus energies association for each element, with medium thick and homogenous samples, are analyzed and corrected. A thorough analysis of the different theoretical and test variables are proven by using real samples, including certified material with known concentration. The simplicity of the calculation method and the results obtained show the method's major precision, with possibilities for the non-destructive routine analysis of different solid samples, using the EDXRF technique (author)

Development of core sampling technique for ITER Type B radwaste

Energy Technology Data Exchange (ETDEWEB)

Kim, S. G.; Hong, K. P.; Oh, W. H.; Park, M. C.; Jung, S. H.; Ahn, S. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

Type B radwaste (intermediate level and long lived radioactive waste) imported from ITER vacuum vessel are to be treated and stored in basement of hot cell building. The Type B radwaste treatment process is composed of buffer storage, cutting, sampling/tritium measurement, tritium removal, characterization, pre-packaging, inspection/decontamination, and storage etc. The cut slices of Type B radwaste components generated from cutting process undergo sampling process before and after tritium removal process. The purpose of sampling is to obtain small pieces of samples in order to investigate the tritium content and concentration of Type B radwaste. Core sampling, which is the candidates of sampling technique to be applied to ITER hot cell, is available for not thick (less than 50 mm) metal without use of coolant. Experimented materials were SS316L and CuCrZr in order to simulate ITER Type B radwaste. In core sampling, substantial secondary wastes from cutting chips will be produced unavoidably. Thus, core sampling machine will have to be equipped with disposal system such as suction equipment. Core sampling is considered an unfavorable method for tool wear compared to conventional drilling.

3D-Laser-Scanning Technique Applied to Bulk Density Measurements of Apollo Lunar Samples

Science.gov (United States)

Macke, R. J.; Kent, J. J.; Kiefer, W. S.; Britt, D. T.

2015-01-01

In order to better interpret gravimetric data from orbiters such as GRAIL and LRO to understand the subsurface composition and structure of the lunar crust, it is import to have a reliable database of the density and porosity of lunar materials. To this end, we have been surveying these physical properties in both lunar meteorites and Apollo lunar samples. To measure porosity, both grain density and bulk density are required. For bulk density, our group has historically utilized sub-mm bead immersion techniques extensively, though several factors have made this technique problematic for our work with Apollo samples. Samples allocated for measurement are often smaller than optimal for the technique, leading to large error bars. Also, for some samples we were required to use pure alumina beads instead of our usual glass beads. The alumina beads were subject to undesirable static effects, producing unreliable results. Other investigators have tested the use of 3d laser scanners on meteorites for measuring bulk volumes. Early work, though promising, was plagued with difficulties including poor response on dark or reflective surfaces, difficulty reproducing sharp edges, and large processing time for producing shape models. Due to progress in technology, however, laser scanners have improved considerably in recent years. We tested this technique on 27 lunar samples in the Apollo collection using a scanner at NASA Johnson Space Center. We found it to be reliable and more precise than beads, with the added benefit that it involves no direct contact with the sample, enabling the study of particularly friable samples for which bead immersion is not possible

Analysis of pure and malachite green doped polysulfone sample using FT-IR technique

Science.gov (United States)

Nayak, Rashmi J.; Khare, P. K.; Nayak, J. G.

2018-05-01

The sample of pure and malachite green doped Polysulfone in the form of foil was prepared by isothermal immersion technique. For the preparation of pure sample 4 gm of Polysulfone was dissolved in 50 ml of Dimethyl farmamide (DMF) solvent, while for the preparation of doped sample 10 mg, 50 mg and 100 mg Malachite Green was mixed with 4 gm of Polysulfone respectively. For the study of structural characterization of these pure and doped sample, Fourier Transform Infra-Red Spectroscopy (FT-IR) technique was used. This study shows that the intensity of transmittance decreases as the ratio of doping increases in pure polysulfone. The reduction in intensity of transmittance is clearly apparent in the present case more over the bands were broader which indicates towards charge transfer interaction between the donar and acceptor molecule.

Versatile real-time interferometer phase-detection system using high-speed digital techniques

International Nuclear Information System (INIS)

Mendell, D.S.; Willett, G.W.

1977-01-01

This paper describes the basic design and philosophy of a versatile real-time interferometer phase-detection system to be used on the 2XIIB and TMX magnetic-fusion experiments at Lawrence Livermore Laboratory. This diagnostics system is a satellite to a host computer and uses high-speed emitter-coupled logic techniques to derive data on real-time phase relationships. The system's input signals can be derived from interferometer outputs over a wide range of reference frequencies. An LSI-11 microcomputer is the interface between the high-speed phase-detection logic, buffer memory, human interaction, and host computer. Phase data on a storage CRT is immediately displayed after each experimental fusion shot. An operator can interrogate this phase data more closely from an interactive control panel, and the host computer can be simultaneously examining the system's buffer memory or arming the system for the next shot

Metal-organic framework based in-syringe solid-phase extraction for the on-site sampling of polycyclic aromatic hydrocarbons from environmental water samples.

Science.gov (United States)

Zhang, Xiaoqiong; Wang, Peiyi; Han, Qiang; Li, Hengzhen; Wang, Tong; Ding, Mingyu

2018-04-01

In-syringe solid-phase extraction is a promising sample pretreatment method for the on-site sampling of water samples because of its outstanding advantages of portability, simple operation, short extraction time, and low cost. In this work, a novel in-syringe solid-phase extraction device using metal-organic frameworks as the adsorbent was fabricated for the on-site sampling of polycyclic aromatic hydrocarbons from environmental waters. Trace polycyclic aromatic hydrocarbons were effectively extracted through the self-made device followed by gas chromatography with mass spectrometry analysis. Owing to the excellent adsorption performance of metal-organic frameworks, the analytes could be completely adsorbed during one adsorption cycle, thus effectively shortening the extraction time. Moreover, the adsorbed analytes could remain stable on the device for at least 7 days, revealing the potential of the self-made device for on-site sampling of degradable compounds in remote regions. The limit of detection ranged from 0.20 to 1.9 ng/L under the optimum conditions. Satisfactory recoveries varying from 84.4 to 104.5% and relative standard deviations below 9.7% were obtained in real samples analysis. The results of this study promote the application of metal-organic frameworks in sample preparation and demonstrate the great potential of in-syringe solid-phase extraction for the on-site sampling of trace contaminants in environmental waters. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two-phase flow void fraction measurement using gamma ray attenuation technique

International Nuclear Information System (INIS)

Silva, R.D. da.

1985-01-01

The present work deals with experimental void fraction measurements in two-phase water-nitrogen flow, by using a gamma ray attenuation technique. Several upward two-phase flow regimes in a vertical tube were simulated. The water flow was varied from 0.13 to 0.44 m 3 /h while the nitrogen flow was varied between 0.01 and 0.1 m 3 /h. The mean volumetric void fraction was determined based on the measured linear void fraction for each flow condition. The results were compared with other authors data and showed a good agreement. (author) [pt

Novel polyamide-based nanofibers prepared by electrospinning technique for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples

International Nuclear Information System (INIS)

Bagheri, Habib; Aghakhani, Ali; Baghernejad, Masoud; Akbarinejad, Alireza

2012-01-01

A novel solid phase microextraction (SPME) fiber was fabricated by electrospinning method in which a polymeric solution was converted to nanofibers using high voltages. A thin stainless steel wire was coated by the network of polymeric nanofibers. The polymeric nanofiber coating on the wire was mechanically stable due to the fine and continuous nanofibers formation around the wire with a three dimensional structure. Polyamide (nylon 6), due to its suitable characteristics was used to prepare the unbreakable SPME nanofiber. The scanning electron microscopy (SEM) images of this new coating showed a diameter range of 100–200 nm for polyamide nanofibers with a homogeneous and porous surface structure. The extraction efficiency of new coating was investigated for headspace solid-phase microextraction (HS-SPME) of some environmentally important chlorophenols from aqueous samples followed by gas chromatography–mass spectrometry (GC–MS) analysis. Effect of different parameters influencing the extraction efficiency including extraction temperature, extraction time, ionic strength and polyamide amount were investigated and optimized. In order to improve the chromatographic behavior of phenolic compounds, all the analytes were derivatized prior to the extraction process using basic acetic anhydride. The detection limits of the method under optimized conditions were in the range of 2–10 ng L −1 . The relative standard deviations (RSD) (n = 3) at the concentration level of 1.7–6.7 ng mL −1 were obtained between 1 and 7.4%. The calibration curves of chlorophenols showed linearity in the range of 27–1330 ng L −1 for phenol and monochlorophenols and 7–1000 ng L −1 for dichloro and trichlorophenols. Also, the proposed method was successfully applied to the extraction of phenol and chlorophenols from real water samples and relative recoveries were between 84 and 98% for all the selected analytes except for 2,4,6 tricholophenol which was between 72 and 74%.

Investigation of Phase Transition-Based Tethered Systems for Small Body Sample Capture

Science.gov (United States)

Quadrelli, Marco; Backes, Paul; Wilkie, Keats; Giersch, Lou; Quijano, Ubaldo; Scharf, Daniel; Mukherjee, Rudranarayan

2009-01-01

This paper summarizes the modeling, simulation, and testing work related to the development of technology to investigate the potential that shape memory actuation has to provide mechanically simple and affordable solutions for delivering assets to a surface and for sample capture and possible return to Earth. We investigate the structural dynamics and controllability aspects of an adaptive beam carrying an end-effector which, by changing equilibrium phases is able to actively decouple the end-effector dynamics from the spacecraft dynamics during the surface contact phase. Asset delivery and sample capture and return are at the heart of several emerging potential missions to small bodies, such as asteroids and comets, and to the surface of large bodies, such as Titan.

Field Sampling Plan for the Operable Units 6-05 and 10-04 Remedial Action, Phase IV

Energy Technology Data Exchange (ETDEWEB)

R. Wells

2006-11-14

This Field Sampling Plan outlines the collection and analysis of samples in support of Phase IV of the Waste Area Group 10, Operable Units 6-05 and 10-04 remedial action. Phase IV addresses the remedial actions to areas with the potential for unexploded ordnance at the Idaho National Laboratory Site. These areas include portions of the Naval Proving Ground, the Arco High-Altitude Bombing Range, and the Twin Buttes Bombing Range. The remedial action consists of removal and disposal of ordnance by high-order detonation, followed by sampling to determine the extent, if any, of soil that might have been contaminated by the detonation activities associated with the disposal of ordnance during the Phase IV activities and explosives during the Phase II activities.

Sensitive trace enrichment of environmental andiandrogen vinclozolin from natural waters and sediment samples using hollow-fiber liquid-phase microextraction.

Science.gov (United States)

Lambropoulou, Dimitra A; Albanis, Triantafyllos A

2004-12-17

The presence of vinclozolin in the environment as far as the endocrine disruption effects in biota are concerned has raised interest in the environmental fate of this compound. In this respect, the present study attempts to investigate the feasibility of applying a novel quantitative method, liquid-phase microextraction (LPME), so as to determine this environmental andiandrogen in environmental samples such as water and sediment samples. The technique involved the use of a small amount (3 microL) of organic solvent impregnated in a hollow fiber membrane, which was attached to the needle of a conventional GC syringe. The extracted samples were analyzed by gas chromatography coupled with electron-capture detection. Experimental LPME conditions such as extraction solvent, stirring rate, content of NaCl and pH were tested. Once LPME was optimized, the performance of the proposed technique was evaluated for the determination of vinclozolin in different types of natural water samples. The recovery of spiked water samples was from 80 to 99%. The procedure was adequate for quantification of vinclozolin in waters at levels of 0.010 to 50 microg/L (r> 0.994) with a detection limit of 0.001 microg/L (S/N= 3). Natural sediment samples from the Aliakmonas River area (Macedonia, Greece) spiked with the target andiandrogen compound were liquid-liquid extracted and analyzed by the methodology developed in this work. No significant interferences from the samples matrix were noticed, indicating that the reported methodology is an innovative tactic for sample preparation in sediment analysis, with a considerable improvement in the achieved detection limits. The results demonstrated that apart from analyte enrichment, the proposed LPME procedure also serves as clean-up method and could be successfully performed to determine trace amounts of vinclozolin in water and sediment samples.

Separation Techniques for Quantification of Radionuclides in Environmental Samples

Directory of Open Access Journals (Sweden)

Dusan Galanda

2009-01-01

Full Text Available The reliable and quantitative measurement of radionuclides is important in order to determine environmental quality and radiation safety, and to monitor regulatory compliance. We examined soil samples from Podunajske Biskupice, near the city of Bratislava in the Slovak Republic, for the presence of several natural (238U, 232Th, 40K and anthropogenic (137Cs, 90Sr, 239Pu, 240Pu, 241Am radionuclides. The area is adjacent to a refinery and hazardous waste processing center, as well as the municipal incinerator plant, and so might possess an unusually high level of ecotoxic metals. We found that the levels of both naturally occurring and anthropogenic radionuclides fell within the expected ranges, indicating that these facilities pose no radiological threat to the local environment. During the course of our analysis, we modified existing techniques in order to allow us to handle the unusually large and complex samples that were needed to determine the levels of 239Pu, 240Pu, and 241Am activity. We also rated three commercial techniques for the separation of 90Sr from aqueous solutions and found that two of them, AnaLig Sr-01 and Empore Extraction Disks, were suitable for the quantitative and reliable separation of 90Sr, while the third, Sr-Spec Resin, was less so. The main criterion in evaluating these methods was the chemical recovery of 90Sr, which was less than we had expected. We also considered speed of separation and additional steps needed to prepare the sample for separation.

Applications of Pitot-meter techniques in two-phase, steam/water, flow

International Nuclear Information System (INIS)

Kastner, W.; Manzano-Ruiz, J.J.

1985-01-01

A simple technique, based on the interpretation of dynamic-pressure readings obtained with local and averaging Pitot-meters (APM) in tow-phase flow, is described and analyzed. The mean dynamic-pressure measurements obtained with an APM allow the calculation of the mass flux of the mixture if the steam quality is known and a combination of two slip-factor correlations is used. The local dynamic-pressure measurements with a multiple Pitot-probe technique provide information on the transition between the most commonly found flow patterns in horizontal piping, i.e. stratified, annular and annular-mist flow

Studies of Phase Transformation in Molecular Crystals Using the Positron Annihilation Technique

DEFF Research Database (Denmark)

Eldrup, Morten Mostgaard; Lightbody, David; Sherwood, John N.

1980-01-01

An examination has been made of the brittle/plastic phase transformation in the molecular crystals cyclohexane, DL-camphene and succinonitrile using the positron annihilation technique. In each material, the transition is characterized by a distinct increase in ortho-positronium lifetime. The inf...

Novel strategies for sample preparation in forensic toxicology.

Science.gov (United States)

Samanidou, Victoria; Kovatsi, Leda; Fragou, Domniki; Rentifis, Konstantinos

2011-09-01

This paper provides a review of novel strategies for sample preparation in forensic toxicology. The review initially outlines the principle of each technique, followed by sections addressing each class of abused drugs separately. The novel strategies currently reviewed focus on the preparation of various biological samples for the subsequent determination of opiates, benzodiazepines, amphetamines, cocaine, hallucinogens, tricyclic antidepressants, antipsychotics and cannabinoids. According to our experience, these analytes are the most frequently responsible for intoxications in Greece. The applications of techniques such as disposable pipette extraction, microextraction by packed sorbent, matrix solid-phase dispersion, solid-phase microextraction, polymer monolith microextraction, stir bar sorptive extraction and others, which are rapidly gaining acceptance in the field of toxicology, are currently reviewed.

Development of a Laser Dopper Anemometer technique for the measurement of two phase dispersed flow

International Nuclear Information System (INIS)

Srinivasan, J.

1978-05-01

A new optical technique using Laser-Doppler Anemometry is presented for the measurement of the local number densities and two-dimensional velocity probability densities of a turbulent dilute two-phase dispersion which has a distribution of particle size and a predominant direction of flow. This technique establishes that by a suitable scheme of discrimination on the signal amplitude, residence time and frequency of the Doppler signals caused by the scattered light from individual particles in the probing volume, the size distribution of moderately large particles in a dilute dispersed flow can be determined. The newly developed Laser-Doppler Anemometer (LDA) technique was applied to a solid particle-water two-phase flow and a water droplet-air two-phase flow. Particular emphasis was placed on turbulent two-phase water droplet-air flow inside a vertical rectangular channel. At each of nine different measuring locations along the transverse axis (starting at 250μ from the channel wall), over 20,000 Doppler signals were individually examined. The particle size and number density distributions, and the axial and lateral velocity distributions of both phases are reported. The analysis reveals some interesting features of two-phase dispersed flow. A film of water on the channel wall was formed due to the deposition of droplets from the flow. The water droplet entrainment from the wall film and the subsequent breakup of some of these into the flow are discussed. A discussion of the relationship between the particle distributions and turbulent flow characteristics is presented

Accelerated Solvent Extraction: An Innovative Sample Extraction Technique for Natural Products

International Nuclear Information System (INIS)

Hazlina Ahmad Hassali; Azfar Hanif Abd Aziz; Rosniza Razali

2015-01-01

Accelerated solvent extraction (ASE) is one of the novel techniques that have been developed for the extraction of phytochemicals from plants in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yield and enhance the quality of extracts. This technique combines elevated temperatures and pressure with liquid solvents. This paper gives a brief overview of accelerated solvent extraction technique for sample preparation and its application to the extraction of natural products. Through practical examples, the effects of operational parameters such as temperature, volume of solvent used, extraction time and extraction yields on the performance of ASE are discussed. It is demonstrated that ASE technique allows reduced solvent consumption and shorter extraction time, while the extraction yields are even higher than those obtained with conventional methods. (author)

Practical aspects of the resin bead technique for mass spectrometric sample loading

International Nuclear Information System (INIS)

Walker, R.L.; Pritchard, C.A.; Carter, J.A.; Smith, D.H.

1976-07-01

Using an anion resin bead as a loading vehicle for uranium and plutonium samples which are to be analyzed isotopically in a mass spectrometer has many advantages over conventional techniques. It is applicable to any laboratory routinely performing such analyses, but should be particularly relevant for Safeguards' purposes. Because the techniques required differ markedly from those of conventional methods, this report has been written to describe them in detail to enable those unfamiliar with the technique to master it with a minimum of trouble

Efficient sample preparation method based on solvent-assisted dispersive solid-phase extraction for the trace detection of butachlor in urine and waste water samples.

Science.gov (United States)

Aladaghlo, Zolfaghar; Fakhari, Alireza; Behbahani, Mohammad

2016-10-01

In this work, an efficient sample preparation method termed solvent-assisted dispersive solid-phase extraction was applied. The used sample preparation method was based on the dispersion of the sorbent (benzophenone) into the aqueous sample to maximize the interaction surface. In this approach, the dispersion of the sorbent at a very low milligram level was achieved by inserting a solution of the sorbent and disperser solvent into the aqueous sample. The cloudy solution created from the dispersion of the sorbent in the bulk aqueous sample. After pre-concentration of the butachlor, the cloudy solution was centrifuged and butachlor in the sediment phase dissolved in ethanol and determined by gas chromatography with flame ionization detection. Under the optimized conditions (solution pH = 7.0, sorbent: benzophenone, 2%, disperser solvent: ethanol, 500 μL, centrifuged at 4000 rpm for 3 min), the method detection limit for butachlor was 2, 3 and 3 μg/L for distilled water, waste water, and urine sample, respectively. Furthermore, the preconcentration factor was 198.8, 175.0, and 174.2 in distilled water, waste water, and urine sample, respectively. Solvent-assisted dispersive solid-phase extraction was successfully used for the trace monitoring of butachlor in urine and waste water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A fully blanketed early B star LTE model atmosphere using an opacity sampling technique

International Nuclear Information System (INIS)

Phillips, A.P.; Wright, S.L.

1980-01-01

A fully blanketed LTE model of a stellar atmosphere with Tsub(e) = 21914 K (thetasub(e) = 0.23), log g = 4 is presented. The model includes an explicit representation of the opacity due to the strongest lines, and uses a statistical opacity sampling technique to represent the weaker line opacity. The sampling technique is subjected to several tests and the model is compared with an atmosphere calculated using the line-distribution function method. The limitations of the distribution function method and the particular opacity sampling method used here are discussed in the light of the results obtained. (author)

Sample preparation techniques based on combustion reactions in closed vessels - A brief overview and recent applications

International Nuclear Information System (INIS)

Flores, Erico M.M.; Barin, Juliano S.; Mesko, Marcia F.; Knapp, Guenter

2007-01-01

In this review, a general discussion of sample preparation techniques based on combustion reactions in closed vessels is presented. Applications for several kinds of samples are described, taking into account the literature data reported in the last 25 years. The operational conditions as well as the main characteristics and drawbacks are discussed for bomb combustion, oxygen flask and microwave-induced combustion (MIC) techniques. Recent applications of MIC techniques are discussed with special concern for samples not well digested by conventional microwave-assisted wet digestion as, for example, coal and also for subsequent determination of halogens

Qualitative and quantitative analysis of different fluid phase in samples of glass beads by X-ray microtomography

International Nuclear Information System (INIS)

Marques, Leonardo C.; Nagata, Rodrigo; Appoloni, Carlos R.; Moreira, Anderson C.; Fernanades, Celso P.

2011-01-01

The X-ray microtomography has showed to be a useful tool for studies of inner structure of reservoir rocks. Moreover recent works have used this methodology to visualize different fluid phases present in these microstructures. In this paper X-ray microtomography has been applied to visualize three fluid phases, separately or simultaneously, in addition to a solid phase (glass beads). Two glass beads samples were manufactured and scanned, one with 0.8 mm (GB1) and other with 0.6 mm (GB2) diameter, respectively. The three fluid phases used were air, oil and a water-salt-potassium iodine solution. Two Skyscan scanners were used, both a 1172 model, which employs X-ray tube with W anode and cone beam. This laboratory based equipment is able to provide images of until 1 μm spatial resolution. One microtomograph is located at CENPES/PETROBRAS and has a CCD camera of 10 mega pixels resolution. It was used to measure the GB1 sample at 4.84 μm spatial resolution. The other one is located at LAMIR/UFPR and has a CCD camera of 11 mega pixels resolution. It was used to measure the GB2 sample at 4.99 μm spatial resolution. GB1 sample was set up with three fluid phases and presented 38.0 (2.7) % of total porosity before fluid presence and 3.5 % and 19.8 %, as lower and higher average porosity values, respectively, after to be filled with them. GB2 sample was set up with oil and water-salt-potassium iodine solution separated. It presented 36.7 (1.9) % of total porosity when dried, 18.7 (2.0) % when filled with oil and 0 % when filled with the solution. The 2D images clearly show the presence of the solution in addition to the air and solid phases. They also show that the presence of oil phase is less clear than the solution. When all the phases are present together in the sample it is possible to differentiate all of them. Individual 3D images are shown for each phase present in the sample. The 3D image containing all the phases is also shown. (author)

Improved Rock Core Sample Break-off, Retention and Ejection System, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The proposed effort advances the design of an innovative core sampling and acquisition system with improved core break-off, retention and ejection features. Phase 1...

The application of statistical and/or non-statistical sampling techniques by internal audit functions in the South African banking industry

Directory of Open Access Journals (Sweden)

D.P. van der Nest

2015-03-01

Full Text Available This article explores the use by internal audit functions of audit sampling techniques in order to test the effectiveness of controls in the banking sector. The article focuses specifically on the use of statistical and/or non-statistical sampling techniques by internal auditors. The focus of the research for this article was internal audit functions in the banking sector of South Africa. The results discussed in the article indicate that audit sampling is still used frequently as an audit evidence-gathering technique. Non-statistical sampling techniques are used more frequently than statistical sampling techniques for the evaluation of the sample. In addition, both techniques are regarded as important for the determination of the sample size and the selection of the sample items

Gas flow headspace liquid phase microextraction.

Science.gov (United States)

Yang, Cui; Qiu, Jinxue; Ren, Chunyan; Piao, Xiangfan; Li, Xifeng; Wu, Xue; Li, Donghao

2009-11-06

There is a trend towards the use of enrichment techniques such as microextraction in the analysis of trace chemicals. Based on the theory of ideal gases, theory of gas chromatography and the original headspace liquid phase microextraction (HS-LPME) technique, a simple gas flow headspace liquid phase microextraction (GF-HS-LPME) technique has been developed, where the extracting gas phase volume is increased using a gas flow. The system is an open system, where an inert gas containing the target compounds flows continuously through a special gas outlet channel (D=1.8mm), and the target compounds are trapped on a solvent microdrop (2.4 microL) hanging on the microsyringe tip, as a result, a high enrichment factor is obtained. The parameters affecting the enrichment factor, such as the gas flow rate, the position of the microdrop, the diameter of the gas outlet channel, the temperatures of the extracting solvent and of the sample, and the extraction time, were systematically optimized for four types of polycyclic aromatic hydrocarbons. The results were compared with results obtained from HS-LPME. Under the optimized conditions (where the extraction time and the volume of the extracting sample vial were fixed at 20min and 10mL, respectively), detection limits (S/N=3) were approximately a factor of 4 lower than those for the original HS-LPME technique. The method was validated by comparison of the GF-HS-LPME and HS-LPME techniques using data for PAHs from environmental sediment samples.

Novel Electrosorption-Enhanced Solid-Phase Microextraction Device for Ultrafast In Vivo Sampling of Ionized Pharmaceuticals in Fish.

Science.gov (United States)

Qiu, Junlang; Wang, Fuxin; Zhang, Tianlang; Chen, Le; Liu, Yuan; Zhu, Fang; Ouyang, Gangfeng

2018-01-02

Decreasing the tedious sample preparation duration is one of the most important concerns for the environmental analytical chemistry especially for in vivo experiments. However, due to the slow mass diffusion paths for most of the conventional methods, ultrafast in vivo sampling remains challenging. Herein, for the first time, we report an ultrafast in vivo solid-phase microextraction (SPME) device based on electrosorption enhancement and a novel custom-made CNT@PPY@pNE fiber for in vivo sampling of ionized acidic pharmaceuticals in fish. This sampling device exhibited an excellent robustness, reproducibility, matrix effect-resistant capacity, and quantitative ability. Importantly, the extraction kinetics of the targeted ionized pharmaceuticals were significantly accelerated using the device, which significantly improved the sensitivity of the SPME in vivo sampling method (limits of detection ranged from 0.12 ng·g -1 to 0.25 ng·g -1 ) and shorten the sampling time (only 1 min). The proposed approach was successfully applied to monitor the concentrations of ionized pharmaceuticals in living fish, which demonstrated that the device and fiber were suitable for ultrafast in vivo sampling and continuous monitoring. In addition, the bioconcentration factor (BCF) values of the pharmaceuticals were derived in tilapia (Oreochromis mossambicus) for the first time, based on the data of ultrafast in vivo sampling. Therefore, we developed and validated an effective and ultrafast SPME sampling device for in vivo sampling of ionized analytes in living organisms and this state-of-the-art method provides an alternative technique for future in vivo studies.

Solid-phase extraction and determination of trace elements in environmental samples using naphthalene adsorbent

International Nuclear Information System (INIS)

Pourreza, N.

2004-01-01

Naphthalene co-precipitated with quaternary ammonium salt such as tetraoctyl ammonium bromide and methyltrioctyl ammonium chloride have been used as adsorbent for solid phase extraction of metal ions such as Hg, Cd and Fe. The metal ions are retained on the adsorbent in a column as their complexes with suitable ligands and eluted by an eluent before instrumental measurements. The optimization of the procedures for solid phase extraction and consequent determination of trace elements and application to environmental samples especially water samples will be discussed. (author)

X-ray spectrometry and X-ray microtomography techniques for soil and geological samples analysis

International Nuclear Information System (INIS)

Kubala-Kukuś, A.; Banaś, D.; Braziewicz, J.; Dziadowicz, M.; Kopeć, E.; Majewska, U.; Mazurek, M.; Pajek, M.; Sobisz, M.; Stabrawa, I.; Wudarczyk-Moćko, J.; Góźdź, S.

2015-01-01

A particular subject of X-ray fluorescence analysis is its application in studies of the multielemental sample of composition in a wide range of concentrations, samples with different matrices, also inhomogeneous ones and those characterized with different grain size. Typical examples of these kinds of samples are soil or geological samples for which XRF elemental analysis may be difficult due to XRF disturbing effects. In this paper the WDXRF technique was applied in elemental analysis concerning different soil and geological samples (therapeutic mud, floral soil, brown soil, sandy soil, calcium aluminum cement). The sample morphology was analyzed using X-ray microtomography technique. The paper discusses the differences between the composition of samples, the influence of procedures with respect to the preparation of samples as regards their morphology and, finally, a quantitative analysis. The results of the studies were statistically tested (one-way ANOVA and correlation coefficients). For lead concentration determination in samples of sandy soil and cement-like matrix, the WDXRF spectrometer calibration was performed. The elemental analysis of the samples was complemented with knowledge of chemical composition obtained by X-ray powder diffraction.

X-ray spectrometry and X-ray microtomography techniques for soil and geological samples analysis

Energy Technology Data Exchange (ETDEWEB)

Kubala-Kukuś, A.; Banaś, D.; Braziewicz, J. [Institute of Physics, Jan Kochanowski University, ul. Świetokrzyska 15, 25-406 Kielce (Poland); Holycross Cancer Center, ul. Artwińskiego 3, 25-734 Kielce (Poland); Dziadowicz, M.; Kopeć, E. [Institute of Physics, Jan Kochanowski University, ul. Świetokrzyska 15, 25-406 Kielce (Poland); Majewska, U. [Institute of Physics, Jan Kochanowski University, ul. Świetokrzyska 15, 25-406 Kielce (Poland); Holycross Cancer Center, ul. Artwińskiego 3, 25-734 Kielce (Poland); Mazurek, M.; Pajek, M.; Sobisz, M.; Stabrawa, I. [Institute of Physics, Jan Kochanowski University, ul. Świetokrzyska 15, 25-406 Kielce (Poland); Wudarczyk-Moćko, J. [Holycross Cancer Center, ul. Artwińskiego 3, 25-734 Kielce (Poland); Góźdź, S. [Holycross Cancer Center, ul. Artwińskiego 3, 25-734 Kielce (Poland); Institute of Public Health, Jan Kochanowski University, IX Wieków Kielc 19, 25-317 Kielce (Poland)

2015-12-01

A particular subject of X-ray fluorescence analysis is its application in studies of the multielemental sample of composition in a wide range of concentrations, samples with different matrices, also inhomogeneous ones and those characterized with different grain size. Typical examples of these kinds of samples are soil or geological samples for which XRF elemental analysis may be difficult due to XRF disturbing effects. In this paper the WDXRF technique was applied in elemental analysis concerning different soil and geological samples (therapeutic mud, floral soil, brown soil, sandy soil, calcium aluminum cement). The sample morphology was analyzed using X-ray microtomography technique. The paper discusses the differences between the composition of samples, the influence of procedures with respect to the preparation of samples as regards their morphology and, finally, a quantitative analysis. The results of the studies were statistically tested (one-way ANOVA and correlation coefficients). For lead concentration determination in samples of sandy soil and cement-like matrix, the WDXRF spectrometer calibration was performed. The elemental analysis of the samples was complemented with knowledge of chemical composition obtained by X-ray powder diffraction.

Extended phase-space methods for enhanced sampling in molecular simulations: a review

Directory of Open Access Journals (Sweden)

Hiroshi eFujisaki

2015-09-01

Full Text Available Molecular Dynamics simulations are a powerful approach to study biomolecular conformational changes or protein-ligand, protein-protein and protein-DNA/RNA interactions. Straightforward applications however are often hampered by incomplete sampling, since in a typical simulated trajectory the system will spend most of its time trapped by high energy barriers in restricted regions of the configuration space. Over the years, several techniques have been designed to overcome this problem and enhance space sampling. Here, we review a class of methods that rely on the idea of extending the set of dynamical variables of the system by adding extra ones associated to functions describing the process under study. In particular, we illustrate the Temperature Accelerated Molecular Dynamics (TAMD, Logarithmic Mean Force Dynamics (LogMFD, andMultiscale Enhanced Sampling (MSES algorithms. We also discuss combinations with techniques for searching reaction paths. We show the advantages presented by this approach and how it allows to quickly sample important regions of the free energy landscape via automatic exploration.

Sampling methods for rumen microbial counts by Real-Time PCR techniques

Directory of Open Access Journals (Sweden)

S. Puppo

2010-02-01

Full Text Available Fresh rumen samples were withdrawn from 4 cannulated buffalo females fed a fibrous diets in order to quantify bacteria concentration in the rumen by Real-Time PCR techniques. To obtain DNA of a good quality from whole rumen fluid, eight (M1-M8 different pre-filtration methods (cheese cloths, glass-fibre and nylon filter in combination with various centrifugation speeds (1000, 5000 and 14,000 rpm were tested. Genomic DNA extraction was performed either on fresh or frozen samples (-20°C. The quantitative bacteria analysis was realized according to Real-Time PCR procedure for Butyrivibrio fibrisolvens reported in literature. M5 resulted the best sampling procedure allowing to obtain a suitable genomic DNA. No differences were revealed between fresh and frozen samples.

Random sampling technique for ultra-fast computations of molecular opacities for exoplanet atmospheres

Science.gov (United States)

Min, M.

2017-10-01

Context. Opacities of molecules in exoplanet atmospheres rely on increasingly detailed line-lists for these molecules. The line lists available today contain for many species up to several billions of lines. Computation of the spectral line profile created by pressure and temperature broadening, the Voigt profile, of all of these lines is becoming a computational challenge. Aims: We aim to create a method to compute the Voigt profile in a way that automatically focusses the computation time into the strongest lines, while still maintaining the continuum contribution of the high number of weaker lines. Methods: Here, we outline a statistical line sampling technique that samples the Voigt profile quickly and with high accuracy. The number of samples is adjusted to the strength of the line and the local spectral line density. This automatically provides high accuracy line shapes for strong lines or lines that are spectrally isolated. The line sampling technique automatically preserves the integrated line opacity for all lines, thereby also providing the continuum opacity created by the large number of weak lines at very low computational cost. Results: The line sampling technique is tested for accuracy when computing line spectra and correlated-k tables. Extremely fast computations ( 3.5 × 105 lines per second per core on a standard current day desktop computer) with high accuracy (≤1% almost everywhere) are obtained. A detailed recipe on how to perform the computations is given.

Sample preparation techniques in trace element analysis by X-ray emission spectroscopy

International Nuclear Information System (INIS)

Valkovic, V.

1983-11-01

The report, written under a research contract with the IAEA, contains a detailed presentation of the most difficult problem encountered in the trace element analysis by methods of the X-ray emission spectroscopy, namely the sample preparation techniques. The following items are covered. Sampling - with specific consideration of aerosols, water, soil, biological materials, petroleum and its products, storage of samples and their handling. Pretreatment of samples - preconcentration, ashing, solvent extraction, ion exchange and electrodeposition. Sample preparations for PIXE - analysis - backings, target uniformity and homogeneity, effects of irradiation, internal standards and specific examples of preparation (aqueous, biological, blood serum and solid samples). Sample preparations for radioactive sources or tube excitation - with specific examples (water, liquid and solid samples, soil, geological, plants and tissue samples). Finally, the problem of standards and reference materials, as well as that of interlaboratory comparisons, is discussed

Solid-phase microextraction for gas chromatographic/mass spectrometric analysis of dimethoate in human biological samples.

Science.gov (United States)

Gallardo, E; Barroso, M; Margalho, C; Cruz, A; Vieira, D N; López-Rivadulla, M

2006-01-01

A new, simple and rapid procedure for the determination of dimethoate in urine and blood samples was developed using direct immersion solid-phase microextraction and gas chromatography/mass spectrometry. This technique required only 0.1 mL of sample, and ethion was used as internal standard. Two types of coated fibre were compared (100 microm polydimethylsiloxane, and 65 microm Carbowax/divinylbenzene). Other parameters, such as extraction temperature, adsorption and desorption time, salt addition, agitation and pH, were optimized to enhance the sensitivity of the method. Limits of detection (LODs) and quantitation (LOQs) were 50 and 100 ng/mL for urine and 200 and 500 ng/mL for blood, respectively. The method was found to be linear between the LOQ and 40 microg/mL for urine, and between the LOQ and 50 microg/mL for blood, with correlation coefficients ranging from 0.9923-0.9996. Precision (intra- and interday) and accuracy were in conformity with the criteria normally accepted in bioanalytical method validation. The mean absolute recoveries of dimethoate were 1.24 and 0.50% for urine and blood, respectively. Because of its simplicity and the fact that small volumes of sample are used, the described method can be successfully used in the diagnosis of poisoning by this pesticide, namely in those situations where the sample volume is limited, as frequently occurs in forensic toxicology. Copyright 2006 John Wiley & Sons, Ltd.

Technique for arterial-phase contrast-enhanced three-dimensional MR angiography of the carotid and vertebral arteries.

Science.gov (United States)

Isoda, H; Takehara, Y; Isogai, S; Takeda, H; Kaneko, M; Nozaki, A; Sun, Y; Foo, T K

1998-08-01

Our goal was to evaluate whether contrast-enhanced three-dimensional MR angiography using the MR Smartprep technique would enable us to obtain arterial-phase MR angiograms of the carotid and vertebral arteries. The study included 35 patients with suspected lesions of the neck in whom the MR Smartprep technique was used for MR angiography performed with a 1.5-T superconducting system. The tracker volume was placed primarily in the middle part of the right common carotid artery. The imaging volume was placed in a coronal direction to include the carotid and vertebral arteries from the aortic arch to the skull base. A centric phase-ordering scheme was used. Imaging times were 20 to 38 seconds for 14 patients and 11 to 16 seconds for 21 patients. By using a smaller tracker volume and an imaging time of less than 16 seconds, we were able to achieve a 100% successful triggering rate and to delineate selectively arterial-phase carotid and vertebral arteries with almost no venous contamination. Contract-enhanced 3-D MR angiography with the MR Smartprep technique was useful for showing arterial-phase carotid and vertebral arteries selectively.

Small-Signal Analysis of Single-Phase and Three-phase DC/AC and AC/DC PWM Converters with the Frequency-Shift Technique

DEFF Research Database (Denmark)

Blaabjerg, Frede; Aquila, A. Dell’; Liserre, Marco

2004-01-01

of dc/dc converters via a 50 Hz frequency-shift. The input admittance is calculated and measured for two study examples (a three-phase active rectifier and a single-phase photovoltaic inverter). These examples show that the purpose of a well designed controller for grid-connected converters......A systematic approach to study dc/ac and ac/dc converters without the use of synchronous transformation is proposed. The use of a frequency-shift technique allows a straightforward analysis of single-phase and three-phase systems. The study of dc/ac and of ac/dc converters is reported to the study...... is to minimize the input admittance in order to make the grid converter more robust to grid disturbance....

Comparative study of quantitative phase imaging techniques for refractometry of optical fibers

Science.gov (United States)

de Dorlodot, Bertrand; Bélanger, Erik; Bérubé, Jean-Philippe; Vallée, Réal; Marquet, Pierre

2018-02-01

The refractive index difference profile of optical fibers is the key design parameter because it determines, among other properties, the insertion losses and propagating modes. Therefore, an accurate refractive index profiling method is of paramount importance to their development and optimization. Quantitative phase imaging (QPI) is one of the available tools to retrieve structural characteristics of optical fibers, including the refractive index difference profile. Having the advantage of being non-destructive, several different QPI methods have been developed over the last decades. Here, we present a comparative study of three different available QPI techniques, namely the transport-of-intensity equation, quadriwave lateral shearing interferometry and digital holographic microscopy. To assess the accuracy and precision of those QPI techniques, quantitative phase images of the core of a well-characterized optical fiber have been retrieved for each of them and a robust image processing procedure has been applied in order to retrieve their refractive index difference profiles. As a result, even if the raw images for all the three QPI methods were suffering from different shortcomings, our robust automated image-processing pipeline successfully corrected these. After this treatment, all three QPI techniques yielded accurate, reliable and mutually consistent refractive index difference profiles in agreement with the accuracy and precision of the refracted near-field benchmark measurement.

Addendum to the Phase 2 Sampling and Analysis Plan for the Clinch River Remedial Investigation

International Nuclear Information System (INIS)

1994-03-01

This document is an addendum to the Phase 2 Sampling and Analysis Plan for the Clinch River Remedial Investigation (DOE 1993). The Department of Energy--Oak Ridge Operations (DOE-ORO) is proposing this addendum to the US Envianmental Protection Agency, Region IV (EPA-IV), and the Tennessee Department of Environment and Conservation (TDEC) as a reduced sampling program on the Clinch River arm of Watts Bar Reservoir and on Poplar Creek. DOE-ORO is proposing to maximize the use of existing data and minimize the collection of new data for water, sediment, and biota during Phase 2 of the Clinch River Remedial Investigation. The existing data along with the additional data collected in Phase 2 would be used to perform a baseline risk assessment and make remedial decisions. DOE-ORO considers that the existing data, the additional data collected in Phase 2, and on-site remedial investigation data would be sufficient to understand the nature and extent of the contamination problem in the Clinch River, perform a baseline risk assessment,and make remedial decisions. This addendum is organized in three sections. The first section provides background information and describes a rationale for modifying the Phase 2 Sampling and Analysis Plan. Section 2 presents a summary of the existing data for the Clinch River arm of Watts Bar Reservoir and an evaluation of the sufficiency of this data for a baseline human health and ecological risk assessment. Section 3 describes the revised Phase 2 Sampling and Analysis Plan for surface water, sediment, and biota in the Clinch River OU and in the Poplar Creek OU

Experimental technique to measure thoron generation rate of building material samples using RAD7 detector

International Nuclear Information System (INIS)

Csige, I.; Szabó, Zs.; Szabó, Cs.

2013-01-01

Thoron ( 220 Rn) is the second most abundant radon isotope in our living environment. In some dwellings it is present in significant amount which calls for its identification and remediation. Indoor thoron originates mainly from building materials. In this work we have developed and tested an experimental technique to measure thoron generation rate in building material samples using RAD7 radon-thoron detector. The mathematical model of the measurement technique provides the thoron concentration response of RAD7 as a function of the sample thickness. For experimental validation of the technique an adobe building material sample was selected for measuring the thoron concentration at nineteen different sample thicknesses. Fitting the parameters of the model to the measurement results, both the generation rate and the diffusion length of thoron was estimated. We have also determined the optimal sample thickness for estimating the thoron generation rate from a single measurement. -- Highlights: • RAD7 is used for the determination of thoron generation rate (emanation). • The described model takes into account the thoron decay and attenuation. • The model describes well the experimental results. • A single point measurement method is offered at a determined sample thickness

Solvent-assisted dispersive solid-phase extraction: A sample preparation method for trace detection of diazinon in urine and environmental water samples.

Science.gov (United States)

Aladaghlo, Zolfaghar; Fakhari, Alireza; Behbahani, Mohammad

2016-09-02

In this research, a sample preparation method termed solvent-assisted dispersive solid-phase extraction (SA-DSPE) was applied. The used sample preparation method was based on the dispersion of the sorbent into the aqueous sample to maximize the interaction surface. In this approach, the dispersion of the sorbent at a very low milligram level was received by inserting a solution of the sorbent and disperser solvent into the aqueous sample. The cloudy solution created from the dispersion of the sorbent in the bulk aqueous sample. After pre-concentration of the diazinon, the cloudy solution was centrifuged and diazinon in the sediment phase dissolved in ethanol and determined by gas chromatography-flame ionization detector. Under the optimized conditions (pH of solution=7.0, Sorbent: benzophenone, 2%, Disperser solvent: ethanol, 500μL, Centrifuge: centrifuged at 4000rpm for 3min), the method detection limit for diazinon was 0.2, 0.3, 0.3 and 0.3μgL(-1) for distilled water, lake water, waste water and urine sample, respectively. Furthermore, the pre-concentration factor was 363.8, 356.1, 360.7 and 353.38 in distilled water, waste water, lake water and urine sample, respectively. SA-DSPE was successfully used for trace monitoring of diazinon in urine, lake and waste water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Instruments and techniques for analysing the time-resolved transverse phase space distribution of high-brightness electron beams

International Nuclear Information System (INIS)

Rudolph, Jeniffa

2012-01-01

This thesis deals with the instruments and techniques used to characterise the transverse phase space distribution of high-brightness electron beams. In particular, methods are considered allowing to measure the emittance as a function of the longitudinal coordinate within the bunch (slice emittance) with a resolution in the ps to sub-ps range. The main objective of this work is the analysis of techniques applicable for the time-resolved phase space characterisation for future high-brightness electron beam sources and single-pass accelerators based on these. The competence built up by understanding and comparing different techniques is to be used for the design and operation of slice diagnostic systems for the Berlin Energy Recovery Linac Project (BERLinPro). In the framework of the thesis, two methods applicable for slice emittance measurements are considered, namely the zero-phasing technique and the use of a transverse deflector. These methods combine the conventional quadrupole scan technique with a transfer of the longitudinal distribution into a transverse distribution. Measurements were performed within different collaborative projects. The experimental setup, the measurement itself and the data analysis are discussed as well as measurement results and simulations. In addition, the phase space tomography technique is introduced. In contrast to quadrupole scan-based techniques, tomography is model-independent and can reconstruct the phase space distribution from simple projected measurements. The developed image reconstruction routine based on the Maximum Entropy algorithm is introduced. The quality of the reconstruction is tested using different model distributions, simulated data and measurement data. The results of the tests are presented. The adequacy of the investigated techniques, the experimental procedures as well as the developed data analysis tools could be verified. The experimental and practical experience gathered during this work, the

Analytical model and error analysis of arbitrary phasing technique for bunch length measurement

Science.gov (United States)

Chen, Qushan; Qin, Bin; Chen, Wei; Fan, Kuanjun; Pei, Yuanji

2018-05-01

An analytical model of an RF phasing method using arbitrary phase scanning for bunch length measurement is reported. We set up a statistical model instead of a linear chirp approximation to analyze the energy modulation process. It is found that, assuming a short bunch (σφ / 2 π → 0) and small relative energy spread (σγ /γr → 0), the energy spread (Y =σγ 2) at the exit of the traveling wave linac has a parabolic relationship with the cosine value of the injection phase (X = cosφr|z=0), i.e., Y = AX2 + BX + C. Analogous to quadrupole strength scanning for emittance measurement, this phase scanning method can be used to obtain the bunch length by measuring the energy spread at different injection phases. The injection phases can be randomly chosen, which is significantly different from the commonly used zero-phasing method. Further, the systematic error of the reported method, such as the influence of the space charge effect, is analyzed. This technique will be especially useful at low energies when the beam quality is dramatically degraded and is hard to measure using the zero-phasing method.

Hypercrosslinked particles for the extraction of sweeteners using dispersive solid-phase extraction from environmental samples.

Science.gov (United States)

Lakade, Sameer S; Zhou, Qing; Li, Aimin; Borrull, Francesc; Fontanals, Núria; Marcé, Rosa M

2018-04-01

This work presents a new extraction material, namely, Q-100, based on hypercrosslinked magnetic particles, which was tested in dispersive solid-phase extraction for a group of sweeteners from environmental samples. The hypercrosslinked Q-100 magnetic particles had the advantage of suitable pore size distribution and high surface area, and showed good retention behavior toward sweeteners. Different dispersive solid-phase extraction parameters such as amount of magnetic particles or extraction time were optimized. Under optimum conditions, Q-100 showed suitable apparent recovery, ranging in the case of river water sample from 21 to 88% for all the sweeteners, except for alitame (12%). The validated method based on dispersive solid-phase extraction using Q-100 followed by liquid chromatography with tandem mass spectrometry provided good linearity and limits of quantification between 0.01 and 0.1 μg/L. The method was applied to analyze samples from river water and effluent wastewater, and four sweeteners (acesulfame, saccharin, cyclamate, and sucralose) were found in both types of sample. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recovery of Picloram and 2,4-Dichlorophenoxyacetic Acid from Aqueous Samples by Reversed-Phase Solid-Phase Extraction

Science.gov (United States)

Martha J.M. Wells; Jerry L. Michael

1987-01-01

Extensive preparation of samples before chromatographic analysis is usually the most time-consuming process in the determination of many organic compounds in environmental matrices. In the past, removal of some organic from aqueous solution was commonly done by liquid/liquid extraction. However, the introduction of stable, covalently bonded reversed-phase sorbents now...

Two-compartment, two-sample technique for accurate estimation of effective renal plasma flow: Theoretical development and comparison with other methods

International Nuclear Information System (INIS)

Lear, J.L.; Feyerabend, A.; Gregory, C.

1989-01-01

Discordance between effective renal plasma flow (ERPF) measurements from radionuclide techniques that use single versus multiple plasma samples was investigated. In particular, the authors determined whether effects of variations in distribution volume (Vd) of iodine-131 iodohippurate on measurement of ERPF could be ignored, an assumption implicit in the single-sample technique. The influence of Vd on ERPF was found to be significant, a factor indicating an important and previously unappreciated source of error in the single-sample technique. Therefore, a new two-compartment, two-plasma-sample technique was developed on the basis of the observations that while variations in Vd occur from patient to patient, the relationship between intravascular and extravascular components of Vd and the rate of iodohippurate exchange between the components are stable throughout a wide range of physiologic and pathologic conditions. The new technique was applied in a series of 30 studies in 19 patients. Results were compared with those achieved with the reference, single-sample, and slope-intercept techniques. The new two-compartment, two-sample technique yielded estimates of ERPF that more closely agreed with the reference multiple-sample method than either the single-sample or slope-intercept techniques

Solid-Phase Extraction Coupled to a Paper-Based Technique for Trace Copper Detection in Drinking Water.

Science.gov (United States)

Quinn, Casey W; Cate, David M; Miller-Lionberg, Daniel D; Reilly, Thomas; Volckens, John; Henry, Charles S

2018-03-20

Metal contamination of natural and drinking water systems poses hazards to public and environmental health. Quantifying metal concentrations in water typically requires sample collection in the field followed by expensive laboratory analysis that can take days to weeks to obtain results. The objective of this work was to develop a low-cost, field-deployable method to quantify trace levels of copper in drinking water by coupling solid-phase extraction/preconcentration with a microfluidic paper-based analytical device. This method has the advantages of being hand-powered (instrument-free) and using a simple "read by eye" quantification motif (based on color distance). Tap water samples collected across Fort Collins, CO, were tested with this method and validated against ICP-MS. We demonstrate the ability to quantify the copper content of tap water within 30% of a reference technique at levels ranging from 20 to 500 000 ppb. The application of this technology, which should be sufficient as a rapid screening tool, can lead to faster, more cost-effective detection of soluble metals in water systems.

Simplified methods for spatial sampling: application to first-phase data of Italian National Forest Inventory (INFC in Sicily

Directory of Open Access Journals (Sweden)

Cullotta S

2006-01-01

Full Text Available Methodological approaches able to integrate data from sample plots with cartographic processes are widely applied. Based on mathematic-statistical techniques, the spatial analysis allows the exploration and spatialization of geographic data. Starting from the punctual information on land use types obtained from the dataset of the first phase of the ongoing new Italian NFI (INFC, a spatialization of land cover classes was carried out using the Inverse Distance Weighting (IDW method. In order to validate the obtained results, an overlay with other vectorial land use data was carried out. In particular, the overlay compared data at different scales, evaluating differences in terms of degree of correspondence between the interpolated and reference land cover.

Analysis of A-15 phase in the system Nb-Au

International Nuclear Information System (INIS)

Silveira, M.F. da.

1982-01-01

The Nb-Au system contains a A-15 structure with a superconducting critical temperature of the order of 11 K. According to the actually available phase diagrams there is some incertainty, whether the stoichiometric composition Nb 3 Au (75% at. Nb and 25% at. Au) occurs within the limits of stability. In the present work the samples (alloys of Nb and Au) are produced using a technique of melting by condenser discharge. The advantage of this technique consists in the possibility to obtain samples with compositions exceeding the limits of stability, as shown by lattice parameter analyses of the phase A-2 (Nb - solid solution) samples. The A-15 phase is obtained by heat treatments of samples crystallized originally in the A-2 structure. The inductively determined critical temperatures are close to the highest reported in the literature for this compound (11,5 K). Further we show by lattice parameter analyses that we are able to obtain the A-15 phase also with metastable compositions, very probably inclusively with the stoichiometric composition. (author) [pt

Neutron activation analysis technique and X-ray fluorescence in bovine liver sample

International Nuclear Information System (INIS)

Maihara, V.A.; Favaro, D.I.T.; Vasconcellos, M.B.A.; Sato, I.M.; Salvador, V.L.

2002-01-01

Many analytical techniques have been used in food and diet analysis in order to determine a great number of nutritional elements, ranging from percentage to ng g -1 , with high sensitivity and accuracy. Instrumental Neutron activation Analysis (INAA) has been employed to certificate many trace elements in biological reference materials. More recently, the X-Ray Fluorescence (FRX-WD) has been also used to determine some essential elements in food samples. The INAA has been applied in nutrition studies in our laboratory at IPEN since the 80 s. For the development of analytical methodologies the use of the reference materials with the same characteristics of the sample analyzed is essential. Several Brazilian laboratories do not have conditions to use these materials due their high cost.In this paper preliminary results of commercial bovine liver sample analyses obtained by INAA and WD-XRF methods are presented. This sample was prepared to be a Brazilian candidate of reference material for a group of laboratories participating in a research project sponsored by FAPESP. The concentrations of some elements like Cl, K, Na, P, S and trace elements Br, Ca, Co, Cu, Fe, Mg, Mn, Mo, Rb, Se and Zn were determined by INAA and WD-XFR. For validation methodology of both techniques, NIST SRM 1577b Bovine Liver reference material was analyzed and the detection limits were calculated. The concentrations of elements determined by both analytical techniques were compared by using the Student's t-test and for Cl, Cu, Fe, K, Mg, Na, Rn and Zn the results do show no statistical difference for 95% significance level. (author)

Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

Energy Technology Data Exchange (ETDEWEB)

Attallah, Olivia A., E-mail: olivia.adly@hu.edu.eg [Center of Nanotechnology, Nile University, 12677 Giza (Egypt); Pharmaceutical Chemistry Department, Heliopolis University, 11777 El Salam, Cairo (Egypt); Girgis, E. [Solid State Physics Department, National Research Center, 12622 Dokki, Giza (Egypt); Advanced Materials and Nanotechnology Lab, CEAS, National Research Center, 12622 Dokki, Giza (Egypt); Abdel-Mottaleb, Mohamed M.S.A. [Center of Nanotechnology, Nile University, 12677 Giza (Egypt)

2016-02-01

Non-aggregated magnetite nanorods with average diameters of 20–30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications. - Highlights: • We synthesize nicotinic acid coated magnetite nanorods via hydrothermal technique • Effect of nicotinic acid concentration on the nanorods properties was significant • Nanorods maintained uniform shape with increased concentration of nicotinic acid • Alterations occurred in particle size, mineral phases and magnetics of coated samples.

Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

International Nuclear Information System (INIS)

Attallah, Olivia A.; Girgis, E.; Abdel-Mottaleb, Mohamed M.S.A.

2016-01-01

Non-aggregated magnetite nanorods with average diameters of 20–30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications. - Highlights: • We synthesize nicotinic acid coated magnetite nanorods via hydrothermal technique • Effect of nicotinic acid concentration on the nanorods properties was significant • Nanorods maintained uniform shape with increased concentration of nicotinic acid • Alterations occurred in particle size, mineral phases and magnetics of coated samples.

Eddy current techniques for super duplex stainless steel characterization

Science.gov (United States)

Camerini, C.; Sacramento, R.; Areiza, M. C.; Rocha, A.; Santos, R.; Rebello, J. M.; Pereira, G.

2015-08-01

Super duplex stainless steel (SDSS) is a two-phase material where the microstructure consists of grains of ferrite (δ) and austenite (γ). SDSS exhibit an attractive combination of properties, such as: strength, toughness and stress corrosion cracking resistance. Nevertheless, SDSS attain these properties after a controlled solution heat treatment, leading to a similar volumetric fraction of δ and γ. Any further heat treatment, welding operation for example, can change the balance of the original phases, or may also lead to precipitation of a deleterious phase, such as sigma (σ). For these situations, the material corrosion resistance is severely impaired. In the present study, several SDSS samples with low σ phase content and non-balanced microstructure were intentionally obtained by thermally treating SDSS specimens. Electromagnetic techniques, conventional Eddy Current Testing (ECT) and Saturated Low Frequency Eddy Current (SLOFEC), were employed to characterize the SDSS samples. The results showed that ECT and SLOFEC are reliable techniques to evaluate σ phase presence in SDSS and can provide an estimation of the δ content.

Improved mesh based photon sampling techniques for neutron activation analysis

International Nuclear Information System (INIS)

Relson, E.; Wilson, P. P. H.; Biondo, E. D.

2013-01-01

The design of fusion power systems requires analysis of neutron activation of large, complex volumes, and the resulting particles emitted from these volumes. Structured mesh-based discretization of these problems allows for improved modeling in these activation analysis problems. Finer discretization of these problems results in large computational costs, which drives the investigation of more efficient methods. Within an ad hoc subroutine of the Monte Carlo transport code MCNP, we implement sampling of voxels and photon energies for volumetric sources using the alias method. The alias method enables efficient sampling of a discrete probability distribution, and operates in 0(1) time, whereas the simpler direct discrete method requires 0(log(n)) time. By using the alias method, voxel sampling becomes a viable alternative to sampling space with the 0(1) approach of uniformly sampling the problem volume. Additionally, with voxel sampling it is straightforward to introduce biasing of volumetric sources, and we implement this biasing of voxels as an additional variance reduction technique that can be applied. We verify our implementation and compare the alias method, with and without biasing, to direct discrete sampling of voxels, and to uniform sampling. We study the behavior of source biasing in a second set of tests and find trends between improvements and source shape, material, and material density. Overall, however, the magnitude of improvements from source biasing appears to be limited. Future work will benefit from the implementation of efficient voxel sampling - particularly with conformal unstructured meshes where the uniform sampling approach cannot be applied. (authors)

Phase separation temperatures of a liquid mixture: Dynamic light scattering technique

International Nuclear Information System (INIS)

Dangudom, K.; Wongtawatnugool, C.; Lacharojana, S.

2010-01-01

Light scattering intensity measurements and photon correlation spectroscopy (PCS) techniques were employed in an investigation of liquid-liquid phase separation behaviour of a mixture of cyclohexane and methanol at seven different compositions. It was found that, except for one composition (29% methanol), the temperature at which the scattering intensity was a maximum did not coincide with the one where the diffusion coefficient was a minimum, as would be for the case of a vapour-liquid system. The difference may be explained in terms of the local density fluctuation and the random walk problem responsible for the peak intensity and the minimum in the diffusion coefficient, respectively. The definition of phase separation temperature, as determined from diffusion process, was also proposed in this work.

A rapid, solid phase extraction (SPE technique for the extraction and gas chromatographic determination lindane pesticide residue in tissue and milk

Directory of Open Access Journals (Sweden)

Yuningsih

2006-03-01

Full Text Available Organochlorine pesticide contamination in feed can cause residue in animal product (tissue and milk, so its become a problem in food safety. Solid phase extraction (SPE has been carried out for determination organochlorine pesticide residues in food animal production. The technique was rapid, not costly and produce limited amount of hazardous-waste. Samples were homogenized with acetonitrile trough cartridge C18, eluted in fluorocyl column with 2% ether-petroleum or acetonitrile fortissue and milk samples respectively. The recoveries of tissue sample by addition lindane standard solution: 0.50 and 1.00 μg are 85.10 and 103.10% respectively, while that of milk with the addition of 0.50, 1.00 and 1.50 μg are 83.80, 88.69 and 91.24% respectively. Three replicates were carried out for every sample. According of validation criteria of FAO/IAEA the recovery for analysis of pesticide residues was 70-110%. Therefore, the method is applicable.

Application of digital sampling techniques to particle identification in scintillation detectors

International Nuclear Information System (INIS)

Bardelli, L.; Bini, M.; Poggi, G.; Taccetti, N.

2002-01-01

In this paper, the use of a fast digitizing system for identification of fast charged particles with scintillation detectors is discussed. The three-layer phoswich detectors developed in the framework of the FIASCO experiment for the detection of light charged particles (LCP) and intermediate mass fragments (IMF) emitted in heavy-ion collisions at Fermi energies are briefly discussed. The standard analog electronics treatment of the signals for particle identification is illustrated. After a description of the digitizer designed to perform a fast digital sampling of the phoswich signals, the feasibility of particle identification on the sampled data is demonstrated. The results obtained with two different pulse shape discrimination analyses based on the digitally sampled data are compared with the standard analog signal treatment. The obtained results suggest, for the present application, the replacement of the analog methods with the digital sampling technique

Uranium content measurement in drinking water samples using track etch technique

International Nuclear Information System (INIS)

Kumar, Mukesh; Kumar, Ajay; Singh, Surinder; Mahajan, R.K.; Walia, T.P.S.

2003-01-01

The concentration of uranium has been assessed in drinking water samples collected from different locations in Bathinda district, Punjab, India. The water samples are taken from hand pumps and tube wells. Uranium is determined using fission track technique. Uranium concentration in the water samples varies from 1.65±0.06 to 74.98±0.38 μg/l. These values are compared with safe limit values recommended for drinking water. Most of the water samples are found to have uranium concentration above the safe limit. Analysis of some heavy metals (Zn, Cd, Pb and Cu) in water is also done in order to see if some correlation exists between the concentration of uranium and these heavy metals. A weak positive correlation has been observed between the concentration of uranium and heavy metals of Pb, Cd and Cu

Attempts to develop a new nuclear measurement technique of β-glucuronidase levels in biological samples

International Nuclear Information System (INIS)

Unak, T.; Avcibasi, U.; Yildirim, Y.; Cetinkaya, B.

2003-01-01

β-Glucuronidase is one of the most important hydrolytic enzymes in living systems and plays an essential role in the detoxification pathway of toxic materials incorporated into the metabolism. Some organs, especially liver and some tumour tissues, have high level of β-glucuronidase activity. As a result the enzymatic activity of some kind of tumour cells, the radiolabelled glucuronide conjugates of cytotoxic, as well as radiotoxic compounds have potentially very valuable diagnostic and therapeutic applications in cancer research. For this reason, a sensitive measurement of β-glucuronidase levels in normal and tumour tissues is a very important step for these kinds of applications. According to the classical measurement method of β-glucuronidase activity, in general, the quantity of phenolphthalein liberated from its glucuronide conjugate, i.e. phenolphthalein-glucuronide, by β-glucuronidase has been measured by use of the spectrophotometric technique. The lower detection limit of phenolphthalein by the spectrophotometric technique is about 1-3 mg. This means that the β-glucuronidase levels could not be detected in biological samples having lower levels of β-glucuronidase activity and therefore the applications of the spectrophotometric technique in cancer research are very seriously limited. Starting from this consideration, we recently attempted to develop a new nuclear technique to measure much lower concentrations of β-glucuronidase in biological samples. To improve the detection limit, phenolphthalein-glucuronide and also phenyl-N-glucuronide were radioiodinated with 131 I and their radioactivity was measured by use of the counting technique. Therefore, the quantity of phenolphthalein or aniline radioiodinated with 131 I and liberated by the deglucuronidation reactivity of β-glucuronidase was used in an attempt to measure levels lower than the spectrophotometric measurement technique. The results obtained clearly verified that 0.01 pg level of

Development of Large Sample Neutron Activation Technique for New Applications in Thailand

International Nuclear Information System (INIS)

Laoharojanaphand, S.; Tippayakul, C.; Wonglee, S.; Channuie, J.

2018-01-01

The development of the Large Sample Neutron Activation Analysis (LSNAA) in Thailand is presented in this paper. The technique had been firstly developed with rice sample as the test subject. The Thai Research Reactor-1/Modification 1 (TRR-1/M1) was used as the neutron source. The first step was to select and characterize an appropriate irradiation facility for the research. An out-core irradiation facility (A4 position) was first attempted. The results performed with the A4 facility were then used as guides for the subsequent experiments with the thermal column facility. The characterization of the thermal column was performed with Cu-wire to determine spatial distribution without and with rice sample. The flux depression without rice sample was observed to be less than 30% while the flux depression with rice sample increased to within 60%. The flux monitors internal to the rice sample were used to determine average flux over the rice sample. The gamma selfshielding effect during gamma measurement was corrected using the Monte Carlo simulation. The ratio between the efficiencies of the volume source and the point source for each energy point was calculated by the MCNPX code. The research team adopted the k0-NAA methodology to calculate the element concentration in the research. The k0-NAA program which developed by IAEA was set up to simulate the conditions of the irradiation and measurement facilities used in this research. The element concentrations in the bulk rice sample were then calculated taking into account the flux depression and gamma efficiency corrections. At the moment, the results still show large discrepancies with the reference values. However, more research on the validation will be performed to identify sources of errors. Moreover, this LS-NAA technique was introduced for the activation analysis of the IAEA archaeological mock-up. The results are provided in this report. (author)

Effect of Preparation Method on Phase Formation Process and Structural and Magnetic Properties of Mn2.5Ge Samples

Directory of Open Access Journals (Sweden)

R. Sobhani

2016-12-01

Full Text Available In this paper, the phase formation process of Mn2.5Ge samples, prepared by mechanical alloying of Mn and Ge metal powders and annealing, has been studied. Results showed that in the milled samples the stable phase is Mn11Ge8 compound with orthorhombic structure and Pnam space group. The value of saturation magnetization increases by increasing milling time from 0.2 up to 1.95 (Am2Kg-1. The remanece of the samples increases by increasing the milling time while the coercivity decreases. Annealing of 15-hour milled sample results in disappearance of Mn and Ge and the formation of new phases of Mn3Ge, Mn5Ge2, Mn5Ge3 and Mn2.3Ge. Mn3Ge is the main phase with Do22 tetragonal structure and I4/mmm space group which is stable and dominant. The enhancement of saturation magnetization in the annealed sample is related to the formation of three new magnetic phases and the increase of coercivity is due to the presence of Mn3Ge compound with tetragonal structure. Studies were replicated on samples made by arc melting method to compare the results and to investigate the effect of the preparation method on phase formation and structural and magnetic properties of the materials. In these samples the saturation value was in range of 0.2 up to 1.95 (Am2Kg-1 depending on preparation methods. Rietveld refinement shows that Mn2.3Ge sample prepared from arc melted under 620oC anealing is single phase. Magnetic analysis of this sample show a saturation magnetization of 5.252(Am2Kg-1 and 0.005 T coercive field.

Analytical dual-energy microtomography: A new method for obtaining three-dimensional mineral phase images and its application to Hayabusa samples

Science.gov (United States)

Tsuchiyama, A.; Nakano, T.; Uesugi, K.; Uesugi, M.; Takeuchi, A.; Suzuki, Y.; Noguchi, R.; Matsumoto, T.; Matsuno, J.; Nagano, T.; Imai, Y.; Nakamura, T.; Ogami, T.; Noguchi, T.; Abe, M.; Yada, T.; Fujimura, A.

2013-09-01

We developed a novel technique called "analytical dual-energy microtomography" that uses the linear attenuation coefficients (LACs) of minerals at two different X-ray energies to nondestructively obtain three-dimensional (3D) images of mineral distribution in materials such as rock specimens. The two energies are above and below the absorption edge energy of an abundant element, which we call the "index element". The chemical compositions of minerals forming solid solution series can also be measured. The optimal size of a sample is of the order of the inverse of the LAC values at the X-ray energies used. We used synchrotron-based microtomography with an effective spatial resolution of >200 nm to apply this method to small particles (30-180 μm) collected from the surface of asteroid 25143 Itokawa by the Hayabusa mission of the Japan Aerospace Exploration Agency (JAXA). A 3D distribution of the minerals was successively obtained by imaging the samples at X-ray energies of 7 and 8 keV, using Fe as the index element (the K-absorption edge of Fe is 7.11 keV). The optimal sample size in this case is of the order of 50 μm. The chemical compositions of the minerals, including the Fe/Mg ratios of ferromagnesian minerals and the Na/Ca ratios of plagioclase, were measured. This new method is potentially applicable to other small samples such as cosmic dust, lunar regolith, cometary dust (recovered by the Stardust mission of the National Aeronautics and Space Administration [NASA]), and samples from extraterrestrial bodies (those from future sample return missions such as the JAXA Hayabusa2 mission and the NASA OSIRIS-REx mission), although limitations exist for unequilibrated samples. Further, this technique is generally suited for studying materials in multicomponent systems with multiple phases across several research fields.

Characterization of mineral phases of agricultural soil samples of Colombian coffee using Moessbauer spectroscopy and X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Humberto Bustos, E-mail: hbustos@ut.edu.co; Lozano, Dagoberto Oyola; Martinez, Yebrayl Antonio Rojas; Pinilla, Marlene Rivera [Universidad del Tolima, Grupo Ciencia de Materiales y Tecnologia en Plasma (Colombia); Alcazar, German Antonio Perez [Universidad del Valle, Grupo Metalurgia Fisica y Teoria de las Transiciones de Fase (Colombia)

2012-03-15

Soil chemical analysis, X-ray diffraction (XRD) and Moessbauer spectrometry (MS) of {sup 57}Fe were used to characterize mineral phases of samples taken from the productive layer (horizon A) of agricultural coffee soil from Tolima (Colombia). Chemical analysis shows the chemical and textural parameters of samples from two different regions of Tolima, i.e., Ibague and Santa Isabel. By XRD phases like illite (I), andesine (A) and quartz (Q) in both samples were identified. The quantity of these phases is different for the two samples. The MS spectra taken at room temperature were adjusted by using five doublets, three of them associated to Fe{sup + 3} type sites and the other two to Fe{sup + 2} type sites. According to their isomer shift and quadrupole splitting the presence of phases like illite (detected by DRX), nontronite and biotite (not detected by XRD) can be postulated.

Phase 1 Characterization sampling and analysis plan West Valley demonstration project.

Energy Technology Data Exchange (ETDEWEB)

Johnson, R. L. (Environmental Science Division)

2011-06-30

The Phase 1 Characterization Sampling and Analysis Plan (CSAP) provides details about environmental data collection that will be taking place to support Phase 1 decommissioning activities described in the Phase 1 Decommissioning Plan for the West Valley Demonstration Project, Revision 2 (Phase I DP; DOE 2009). The four primary purposes of CSAP data collection are: (1) pre-design data collection, (2) remedial support, (3) post-remediation status documentation, and (4) Phase 2 decision-making support. Data collection to support these four main objectives is organized into two distinct data collection efforts. The first is data collection that will take place prior to the initiation of significant Phase 1 decommissioning activities (e.g., the Waste Management Area [WMA] 1 and WMA 2 excavations). The second is data collection that will occur during and immediately after environmental remediation in support of remediation activities. Both data collection efforts have a set of well-defined objectives that encompass the data needs of the four main CSAP data collection purposes detailed in the CSAP. The main body of the CSAP describes the overall data collection strategies that will be used to satisfy data collection objectives. The details of pre-remediation data collection are organized by WMA. The CSAP contains an appendix for each WMA that describes the details of WMA-specific pre-remediation data collection activities. The CSAP is intended to expand upon the data collection requirements identified in the Phase 1 Decommissioning Plan. The CSAP is intended to tightly integrate with the Phase 1 Final Status Survey Plan (FSSP). Data collection described by the CSAP is consistent with the FSSP where appropriate and to the extent possible.

Evaluation of alias-less reconstruction by pseudo-parallel imaging in a phase-scrambling fourier transform technique

International Nuclear Information System (INIS)

Ito, Satoshi; Kawawa, Yasuhiro; Yamada, Yoshifumi

2010-01-01

We propose an image reconstruction technique in which parallel image reconstruction is performed based on the sensitivity encoding (SENSE) algorithm using only a single set of signals. The signal obtained in the phase-scrambling Fourier transform (PSFT) imaging technique can be transformed to the signal described by the Fresnel transform of the objects, which is known as the diffracted wave-front equation of the object in acoustics or optics. Since the Fresnel transform is a convolution integral on the object space, the space where the PSFT signal exists can be considered as both in the Fourier domain and in the object domain. This notable feature indicates that weighting functions corresponding to the sensitivity of radiofrequency (RF) coils can be approximately given in the PSFT signal space. Therefore, we can obtain two folded images from a single set of signals with different weighting functions, and image reconstruction based on the SENSE parallel imaging algorithm is possible using a series of folded images. Simulation and experimental studies showed that almost alias-free images can be synthesized using a single signal that does not satisfy the sampling theorem. (author)

Direct sampling technique of bees on Vriesea philippocoburgii (Bromeliaceae, Tillandsioideae flowers

Directory of Open Access Journals (Sweden)

Afonso Inácio Orth

2004-11-01

Full Text Available In our study on Vriesea philippocoburgii Wawra pollination, due to the small proportion of flowers in anthesis on a single day and the damage caused to inflorescences when netting directly on flowers, we used the direct sampling technique (DST of bees on flowers. This technique was applied to 40 flowering plants and resulted in the capture of 160 specimens, belonging to nine genera of Apoidea and separated into 19 morph species. As DST maintains the integrity of flowers for later Bees’ visits, it can enhance the survey’s performance, constituting an alternative methodology for the collection of bees visiting flowering plants.

Modified Dual Three-Pulse Modulation technique for single-phase inverter topology

Science.gov (United States)

Sree Harsha, N. R.; Anitha, G. S.; Sreedevi, A.

2016-01-01

In a recent paper, a new modulation technique called Dual Three Pulse Modulation (DTPM) was proposed to improve the efficiency of the power converters of the Electric/Hybrid/Fuel-cell vehicles. It was simulated in PSIM 9.0.4 and uses analog multiplexers to generate the modulating signals for the DC/DC converter and inverter. The circuit used is complex and many other simulation softwares do not support the analog multiplexers as well. Also, the DTPM technique produces modulating signals for the converter, which are essentially needed to produce the modulating signals for the inverter. Hence, it cannot be used efficiently to switch the valves of a stand-alone inverter. We propose a new method to generate the modulating signals to switch MOSFETs of a single phase Dual-Three pulse Modulation based stand-alone inverter. The circuits proposed are simulated in Multisim 12.0. We also show an alternate way to switch a DC/DC converter in a way depicted by DTPM technique both in simulation (MATLAB/Simulink) and hardware. The circuitry is relatively simple and can be used for the further investigations of DTPM technique.

Identification of unknown sample using NAA, EDXRF, XRD techniques

International Nuclear Information System (INIS)

Dalvi, Aditi A.; Swain, K.K.; Chavan, Trupti; Remya Devi, P.S.; Wagh, D.N.; Verma, R.

2015-01-01

Analytical Chemistry Division (ACD), Bhabha Atomic Research Centre (BARC) receives samples from law enforcement agencies such as Directorate of Revenue Intelligence, Customs for analysis. Five unknown grey powdered samples were received for identification and were suspected to be Iridium (Ir). Identification of unknown sample is always a challenging task and suitable analytical techniques have to be judiciously utilized for arriving at the conclusion. Qualitative analysis was carried out using Jordan Valley, EX-3600 M Energy dispersive X-ray fluorescence (EDXRF) spectrometer at ACD, BARC. A SLP series LEO Si (Li) detector (active area: 30 mm 2 ; thickness: 3.5 mm; resolution: 140 eV at 5.9 keV of Mn K X-ray) was used during the measurement and only characteristic X-rays of Ir (Lα: 9.17 keV and Lβ: 10.70 keV) was seen in the X-ray spectrum. X-ray diffraction (XRD) measurement results indicated that the Ir was in the form of metal. To confirm the XRD data, neutron activation analysis (NAA) was carried out by irradiating samples and elemental standards (as comparator) in graphite reflector position of Advanced Heavy Water Reactor Critical Facility (AHWR CF) reactor, BARC, Mumbai. After suitable decay period, gamma activity measurements were carried out using 45% HPGe detector coupled to 8 k multi channel analyzer. Characteristic gamma line at 328.4 keV of the activation product 194 Ir was used for quantification of iridium and relative method of NAA was used for concentration calculations. NAA results confirmed that all the samples were Iridium metal. (author)

Hard x-ray microimaging techniques based on phase zone plates

International Nuclear Information System (INIS)

Lai, B.; Yun, W.B.; Legnini, D.; Xiao, Y.H.; Chrzas, J.

1992-01-01

Phase zone plates of high focusing efficiency and submicron resolution have been demonstrated in the hard x-ray region. A scanning microscope based on these focusing optics will create many new applications. Preliminary results in the applications of the microscope are reported here. In the area of imaging, we have utilized absorption contrast to clearly identify the locations of Au and Ni constituents in a sample of two interleaved grids. Micro-EXAFS spectra has also been obtained on a Ni foil. Fluorescence from a nuclear fuel sample, as an example of microanalysis, has revealed the elemental distribution at the interfaces. Lastly, microdiffraction from AgBr crystallites has been studied. 5 figs, 7 refs

Development of SYVAC sampling techniques

International Nuclear Information System (INIS)

Prust, J.O.; Dalrymple, G.J.

1985-04-01

This report describes the requirements of a sampling scheme for use with the SYVAC radiological assessment model. The constraints on the number of samples that may be taken is considered. The conclusions from earlier studies using the deterministic generator sampling scheme are summarised. The method of Importance Sampling and a High Dose algorithm, which are designed to preferentially sample in the high dose region of the parameter space, are reviewed in the light of experience gained from earlier studies and the requirements of a site assessment and sensitivity analyses. In addition the use of an alternative numerical integration method for estimating risk is discussed. It is recommended that the method of Importance Sampling is developed and tested for use with SYVAC. An alternative numerical integration method is not recommended for investigation at this stage but should be the subject of future work. (author)

Operable Unit 3-13, Group 3, Other Surface Soils (Phase II) Field Sampling Plan

Energy Technology Data Exchange (ETDEWEB)

G. L. Schwendiman

2006-07-27

This Field Sampling Plan describes the Operable Unit 3-13, Group 3, Other Surface Soils, Phase II remediation field sampling activities to be performed at the Idaho Nuclear Technology and Engineering Center located within the Idaho National Laboratory Site. Sampling activities described in this plan support characterization sampling of new sites, real-time soil spectroscopy during excavation, and confirmation sampling that verifies that the remedial action objectives and remediation goals presented in the Final Record of Decision for Idaho Nuclear Technology and Engineering Center, Operable Unit 3-13 have been met.

Phase I metabolism of the recently emerged synthetic cannabinoid CUMYL-PEGACLONE and detection in human urine samples.

Science.gov (United States)

Mogler, Lukas; Wilde, Maurice; Huppertz, Laura M; Weinfurtner, Georg; Franz, Florian; Auwärter, Volker

2018-05-01

Indole-, indazole-, or azaindole-based synthetic cannabinoids (SCs), bearing a cumyl substituent are a widespread, recreationally used subgroup of new psychoactive substances (NPS). The latest cumyl-derivative, CUMYL-PEGACLONE, emerged in December 2016 on the German drug market. The substance features a novel γ-carboline core structure, which is most likely synthesized to bypass generic legislative approaches to control SCs by prohibiting distinct core structures. Using liquid chromatography-tandem mass spectrometry and liquid chromatography-high resolution mass spectrometry techniques, the main in vivo phase I metabolites of this new substance were detected. A pooled human liver microsome assay was applied to generate in vitro reference spectra of CUMYL-PEGACLONE phase I metabolites. Additionally, 30 urine samples were investigated leading to 22 in vivo metabolites. A metabolite mono-hydroxylated at the γ-carbolinone core system and a metabolite with an additional carbonyl group at the pentyl side chain were evaluated as highly specific and sensitive markers to proof CUMYL-PEGACLONE uptake. Moreover, 3 immunochemical assays commonly used for SC screening in urine were tested for their capability of detecting the new drug but failed due to insufficient cross-reactivity. Copyright © 2018 John Wiley & Sons, Ltd.

Characterisation of phase evolution under load by means of phase contrast imaging using synchrotron radiation

International Nuclear Information System (INIS)

Besseghini, S.; Stortiero, F.; Carcano, G.; Villa, E.; Mancini, L.; Tromba, G.; Zanini, F.; Montanari, F.; Airoldi, G.

2003-01-01

Phase contrast radiography (PCR) is a quite novel technique that is collecting increasing attention due to the possibility to obtain image information in presence of very small differences in the densities of the materials under analysis. Phase contrast imaging (PCI) has some specific advantage when compared with common microscopic techniques: (a) no special preparation of the sample is needed (b) the simultaneously investigated area is very large and (c) it allows the setting up of complex experimental apparatus. The results here presented are a good evidence of these three advantages. In this paper, we report on the application of phase contrast imaging in the study of the phase evolution during pseudoelastic transformation in the NiTiCu shape memory alloys (SMAs). The investigation was undertaken with the aim to identify some modification of the structure taking place at the end of the transformation plateau in the pseudoelastic behaviour of the alloy

Determination of neonicotinoid insecticides and strobilurin fungicides in particle phase atmospheric samples by liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Raina-Fulton, Renata

2015-06-03

A liquid chromatography-tandem mass spectrometry method has been developed for the determination of neonicotinoids and strobilurin fungicides in the particle phase fraction of atmosphere samples. Filter samples were extracted with pressurized solvent extraction, followed by a cleanup step with solid phase extraction. Method detection limits for the seven neonicotinoid insecticides and six strobilurin fungicides were in the range of 1.0-4.0 pg/m(3). Samples were collected from June to September 2013 at two locations (Osoyoos and Oliver) in the southern Okanagan Valley Agricultural Region of British Columbia, where these insecticides and fungicides are recommended for use on tree fruit crops (apples, pears, cherries, peaches, apricots) and vineyards. This work represents the first detection of acetamiprid, imidacloprid, clothianidin, kresoxim-methyl, pyraclostrobin, and trifloxystrobin in particle phase atmospheric samples collected in the Okanagan Valley in Canada. The highest particle phase atmospheric concentrations were observed for imidacloprid, pyraclostrobin, and trifloxystrobin at 360.0, 655.6, and 1908.2 pg/m(3), respectively.

PWR steam generator chemical cleaning. Phase II. Final report

International Nuclear Information System (INIS)

1980-01-01

Two techniques believed capable of chemically dissolving the corrosion products in the annuli between tubes and support plates were developed in laboratory work in Phase I of this project and were pilot tested in Indian Point Unit No. 1 steam generators. In Phase II, one of the techniques was shown to be inadequate on an actual sample taken from an Indian Point Unit No. 2 steam generator. The other technique was modified slightly, and it was demonstrated that the tube/support plate annulus could be chemically cleaned effectively

Waste retrieval sluicing system vapor sampling and analysis plan for evaluation of organic emissions, process test phase III

International Nuclear Information System (INIS)

SASAKI, L.M.

1999-01-01

This sampling and analysis plan identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained to address vapor issues related to the sluicing of tank 241-C-106. Sampling will be performed in accordance with Waste Retrieval Sluicing System Emissions Collection Phase III (Jones 1999) and Process Test Plan Phase III, Waste Retrieval Sluicing System Emissions Collection (Powers 1999). Analytical requirements include those specified in Request for Ecology Concurrence on Draft Strategy/Path Forward to Address Concerns Regarding Organic Emissions from C-106 Sluicing Activities (Peterson 1998). The Waste Retrieval Sluicing System was installed to retrieve and transfer high-heat sludge from tank 241-C-106 to tank 241-AY-102, which is designed for high-heat waste storage. During initial sluicing of tank 241-C-106 in November 1998, operations were halted due to detection of unexpected high volatile organic compounds in emissions that exceeded regulatory permit limits. Several workers also reported smelling sharp odors and throat irritation. Vapor grab samples from the 296-C-006 ventilation system were taken as soon as possible after detection; the analyses indicated that volatile and semi-volatile organic compounds were present. In December 1998, a process test (phase I) was conducted in which the pumps in tanks 241-C-106 and 241-AY-102 were operated and vapor samples obtained to determine constituents that may be present during active sluicing of tank 241-C-106. The process test was suspended when a jumper leak was detected. On March 7, 1999, phase I1 of the process test was performed; the sluicing system was operated for approximately 7 hours and was ended using the controlled shutdown method when the allowable amount of solids were transferred to 241-AY-102. The phase II test was successful, however, further testing is required to obtain vapor samples at higher emission levels

Nonactivation interaction techniques in the analysis of environmental samples

International Nuclear Information System (INIS)

Tolgyessy, J.

1986-01-01

Nonactivation interaction analytical methods are based on the interaction processes of nuclear and X-ray radiation with a sample, leading to their absorption and backscattering, to the ionization of gases or excitation of fluorescent X-ray by radiation, but not to the activation of determined elements. From the point of view of environmental analysis, the most useful nonactivation interaction techniques are X-ray fluorescence by photon or charged particle excitation, ionization of gases by nuclear radiation, elastic scattering of charged particles and backscattering of beta radiation. The significant advantage of these methods is that they are nondestructive. (author)

Method for utilizing properties of the sinc(x) function for phase retrieval on nyquist-under-sampled data

Science.gov (United States)

Dean, Bruce H. (Inventor); Smith, Jeffrey Scott (Inventor); Aronstein, David L. (Inventor)

2012-01-01

Disclosed herein are systems, methods, and non-transitory computer-readable storage media for simulating propagation of an electromagnetic field, performing phase retrieval, or sampling a band-limited function. A system practicing the method generates transformed data using a discrete Fourier transform which samples a band-limited function f(x) without interpolating or modifying received data associated with the function f(x), wherein an interval between repeated copies in a periodic extension of the function f(x) obtained from the discrete Fourier transform is associated with a sampling ratio Q, defined as a ratio of a sampling frequency to a band-limited frequency, and wherein Q is assigned a value between 1 and 2 such that substantially no aliasing occurs in the transformed data, and retrieves a phase in the received data based on the transformed data, wherein the phase is used as feedback to an optical system.

A technique for measuring an electron beam close-quote s longitudinal phase space with sub-picosecond resolution

International Nuclear Information System (INIS)

Crosson, E.R.; Berryman, K.W.; Richman, B.A.; Smith, T.I.; Swent, R.L.

1996-01-01

We have developed a technique for measuring the longitudinal phase space distribution of the Stanford Superconducting Accelerator close-quote s (SCA) electron beam which involves applying tomographic techniques to energy spectra taken as a function of the relative phase between the beam and the accelerating field, and optionally, as a function of the strength of a variable dispersion section in the system. The temporal profile of the beam obtained by projecting the inferred distribution onto the time axis is compared with that obtained from interferometric transition radiation measurements. copyright 1996 American Institute of Physics

Grimsel colloid exercise, an international intercomparison exercise on the sampling and characterization of groundwater colloids

International Nuclear Information System (INIS)

Degueldre, C.

1990-01-01

The Grimsel colloid exercise was an intercomparison exercise which consisted of an in situ sampling phase followed by a colloid characterization step. The goal of this benchmark exercise, which involved 12 laboratories, was to evaluate both sampling and characterization techniques with emphasis on the colloid specific size distribution. The sampling phase took place at the Grimsel test site between 1 and 13 February 1988 and the participating groups produced colloid samples using various methods. This work was carried out within the Community COCO Club, as a component of the Mirage project (second phase)

Comparison of Techniques for Sampling Adult Necrophilous Insects From Pig Carcasses.

Science.gov (United States)

Cruise, Angela; Hatano, Eduardo; Watson, David W; Schal, Coby

2018-02-06

Studies of the pre-colonization interval and mechanisms driving necrophilous insect ecological succession depend on effective sampling of adult insects and knowledge of their diel and successional activity patterns. The number of insects trapped, their diversity, and diel periodicity were compared with four sampling methods on neonate pigs. Sampling method, time of day and decomposition age of the pigs significantly affected the number of insects sampled from pigs. We also found significant interactions of sampling method and decomposition day, time of sampling and decomposition day. No single method was superior to the other methods during all three decomposition days. Sampling times after noon yielded the largest samples during the first 2 d of decomposition. On day 3 of decomposition however, all sampling times were equally effective. Therefore, to maximize insect collections from neonate pigs, the method used to sample must vary by decomposition day. The suction trap collected the most species-rich samples, but sticky trap samples were the most diverse, when both species richness and evenness were factored into a Shannon diversity index. Repeated sampling during the noon to 18:00 hours period was most effective to obtain the maximum diversity of trapped insects. The integration of multiple sampling techniques would most effectively sample the necrophilous insect community. However, because all four tested methods were deficient at sampling beetle species, future work should focus on optimizing the most promising methods, alone or in combinations, and incorporate hand-collections of beetles. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multi-element analysis of lubricant oil by WDXRF technique using thin-film sample preparation

International Nuclear Information System (INIS)

Scapin, M. A.; Salvador, V. L. R.; Lopes, C. D.; Sato, I. M.

2006-01-01

The quantitative analysis of the chemical elements in matrices like oils or gels represents a challenge for the analytical chemists. The classics methods or instrumental techniques such as atomic absorption spectrometry (AAS) and plasma optical emission spectrometry (ICP-OES) need chemical treatments, mainly sample dissolution and degradation processes. X-ray fluorescence technique allows a direct and multi-element analysis without previous sample treatments. In this work, a sensible method for the determination of elements Mg, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Sn, Ba and Pb in lubricating oil is presented. The x-ray fluorescence (WDXRF) technique using linear regression method and thin film sample preparation was used. The validation of the methodology (repeatability and accuracy) was obtained by the analysis of the standard reference materials SRM Alpha AESAR lot 703527D, applying the Chauvenet, Cochrane, ANOVA and Z-score statistical tests. The method presents a relative standard deviation lower than 10% for all the elements, except for Pb determination (RSD Pb 15%). The Z-score values for all the elements were in the range -2 < Z < 2, indicating a very good accuracy.(Full text)

Human mixed lymphocyte cultures. Evaluation of microculture technique utilizing the multiple automated sample harvester (MASH)

Science.gov (United States)

Thurman, G. B.; Strong, D. M.; Ahmed, A.; Green, S. S.; Sell, K. W.; Hartzman, R. J.; Bach, F. H.

1973-01-01

Use of lymphocyte cultures for in vitro studies such as pretransplant histocompatibility testing has established the need for standardization of this technique. A microculture technique has been developed that has facilitated the culturing of lymphocytes and increased the quantity of cultures feasible, while lowering the variation between replicate samples. Cultures were prepared for determination of tritiated thymidine incorporation using a Multiple Automated Sample Harvester (MASH). Using this system, the parameters that influence the in vitro responsiveness of human lymphocytes to allogeneic lymphocytes have been investigated. PMID:4271568

Modeling and Testing of Phase Transition-Based Deployable Systems for Small Body Sample Capture

Science.gov (United States)

Quadrelli, Marco; Backes, Paul; Wilkie, Keats; Giersch, Lou; Quijano, Ubaldo; Keim, Jason; Mukherjee, Rudranarayan

2009-01-01

This paper summarizes the modeling, simulation, and testing work related to the development of technology to investigate the potential that shape memory actuation has to provide mechanically simple and affordable solutions for delivering assets to a surface and for sample capture and return. We investigate the structural dynamics and controllability aspects of an adaptive beam carrying an end-effector which, by changing equilibrium phases is able to actively decouple the end-effector dynamics from the spacecraft dynamics during the surface contact phase. Asset delivery and sample capture and return are at the heart of several emerging potential missions to small bodies, such as asteroids and comets, and to the surface of large bodies, such as Titan.

Structural effects of C60+ bombardment on various natural mineral samples-Application to analysis of organic phases in geological samples

International Nuclear Information System (INIS)

Siljestroem, S.; Lausmaa, J.; Hode, T.; Sundin, M.; Sjoevall, P.

2011-01-01

Organic phases trapped inside natural mineral samples are of considerable interest in astrobiology, geochemistry and geobiology. Examples of such organic phases are microfossils, kerogen and oil. Information about these phases is usually retrieved through bulk crushing of the rock which means both a risk of contamination and that the composition and spatial distribution of the organics to its host mineral is lost. An attractive of way to retrieve information about the organics in the rock is depth profiling using a focused ion beam. Recently, it was shown that it is possible to obtain detailed mass spectrometric information from oil-bearing fluid inclusions, i.e. small amounts of oil trapped inside a mineral matrix, using ToF-SIMS. Using a 10 keV C 60 + sputter beam and a 25 keV Bi 3 + analysis beam, oil-bearing inclusions in different minerals were opened and analysed individually. However, sputtering with a C 60 + beam also induced other changes to the mineral surface, such as formation of topographic features and carbon deposition. In this paper, the cause of these changes is explored and the consequences of the sputter-induced features on the analysis of organic phases in natural mineral samples (quartz, calcite and fluorite) in general and fluid inclusions in particular are discussed. The dominating topographical features that were observed when a several micrometers deep crater is sputtered with 10 keV C 60 + ions on a natural mineral surface are conical-shaped and ridge-like structures that may rise several micrometers, pointing in the direction of the incident C 60 + ion beam, on an otherwise flat crater bottom. The sputter-induced structures were found to appear at places with different chemistry than the host mineral, including other minerals phases and fluid inclusions, while structural defects in the host material, such as polishing marks or scratches, did not necessarily result in sputter-induced structures. The ridge-like structures were often covered

[Influence of Natural Dissolved Organic Matter on the Passive Sampling Technique and its Application].

Science.gov (United States)

Yu, Shang-yun; Zhou, Yan-mei

2015-08-01

This paper studied the effects of different concentrations of natural dissolved organic matter (DOM) on the passive sampling technique. The results showed that the presence of DOM affected the organic pollutant adsorption ability of the membrane. For lgK(OW), 3-5, DOM had less impact on the adsorption of organic matter by the membrane; for lgK(OW), > 5.5, DOM significantly increased the adsorption capacity of the membrane. Meanwhile, LDPE passive sampling technique was applied to monitor PAHs and PAEs in pore water of three surface sediments in Taizi River. All of the target pollutants were detected in varying degrees at each sampling point. Finally, the quotient method was used to assess the ecological risks of PAHs and PAEs. The results showed that fluoranthene exceeded the reference value of the aquatic ecosystem, meaning there was a big ecological risk.

Precision mass measurements using the Phase-Imaging Ion-Cyclotron-Resonance detection technique

CERN Document Server

Karthein, Jonas

This thesis presents the implementation and improvement of the Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) detection technique at the ISOLTRAP experiment, located at the ISOLDE / CERN, with the purpose of on-line high-precision and high-resolution mass spectrometry. Extensive simulation studies were performed with the aim of improving the phase-imaging resolution and finding the optimal position for detector placement. Following the outcome of these simulations, the detector was moved out of a region of electric-field distortion and closer to the center of the Penning trap, showing a dramatic improvement in the quality and reproducibility of the phase-imaging measurements. A new image reconstitution and analysis software for the MCP-PS detector was written in Python and ROOT and introduced in the framework of PI-ICR mass measurements. The state of the art in the field of time-of-flight ion-cyclotron-resonance measurements is illustrated through an analysis of on-line measurements of the mirror nuclei $...

Phase aberrations and beam cleanup techniques in carbon-dioxide laser fusion systems

International Nuclear Information System (INIS)

Viswanathan, V.K.

1981-01-01

This paper describes the various carbon dioxide laser fusion systems at Los Alamos from the point of view of an optical designer. The types of phase aberrations present in these systems, as well as the beam cleanup techniques that can be used to improve the beam optical quality, are discussed. As this is a review article, some previously published results are also used where relevant

Heat-transfer testing procedures in phase B shuttle studies with emphasis on phase change data improvement

Science.gov (United States)

Throckmorton, D. A.

1972-01-01

The procedures used in the application of the phase change technique to the phase B shuttle configuration are discussed along with factors which may affect data accuracy. These factors include variation of thermal properties of phase change model material, sensitivity of measured heat transfer coefficients to the assumed value of the adiabatic to total temperature ratio, and wall temperature effects. These sensitivities are illustrated in sample calculations for a shuttle geometry. Factors which may affect the visual clarity and interpretation of phase change data are discussed, and a method of improving photographic data quality through the use of polarized light is presented.

Final report for 105-N Basin sediment disposition task, phase 2 samples BOMPC8 and BOMPC9

International Nuclear Information System (INIS)

Esch, R.A.

1998-01-01

This document is the final report deliverable for Phase 2 analytical work for the 105-N Basin Sediment Disposition Task. On December 23, 1997, ten samples were received at the 222-S Laboratory as follows: two (2) bottles of potable water, six (6) samples for process control testing and two (2) samples for characterization. Analyses were performed in accordance with the Letter of Instruction for Phase 2 Analytical Work for the 105-N Basin Sediment Disposition Task (Logan and Kessner, 1997) (Attachment 7) and 105-N Basin Sediment Disposition Phase-Two Sampling and Analysis Plan (SAP) (Smith, 1997). The analytical results are included in Table 1. This document provides the values of X/Qs for the onsite and offsite receptors, taking into account the building wake and the atmospheric stability effects. X/Qs values for the potential fire accident were also calculated. In addition, the unit dose were calculated for the mixtures of isotopes

Ultrasound-assisted leaching-dispersive solid-phase extraction followed by liquid-liquid microextraction for the determination of polybrominated diphenyl ethers in sediment samples by gas chromatography-tandem mass spectrometry.

Science.gov (United States)

Fontana, Ariel R; Lana, Nerina B; Martinez, Luis D; Altamirano, Jorgelina C

2010-06-30

Ultrasound-assisted leaching-dispersive solid-phase extraction followed by dispersive liquid-liquid microextraction (USAL-DSPE-DLLME) technique has been developed as a new analytical approach for extracting, cleaning up and preconcentrating polybrominated diphenyl ethers (PBDEs) from sediment samples prior gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. In the first place, PBDEs were leached from sediment samples by using acetone. This extract was cleaned-up by DSPE using activated silica gel as sorbent material. After clean-up, PBDEs were preconcentrated by using DLLME technique. Thus, 1 mL acetone extract (disperser solvent) and 60 microL carbon tetrachloride (extraction solvent) were added to 5 mL ultrapure water and a DLLME technique was applied. Several variables that govern the proposed technique were studied and optimized. Under optimum conditions, the method detection limits (MDLs) of PBDEs calculated as three times the signal-to-noise ratio (S/N) were within the range 0.02-0.06 ng g(-1). The relative standard deviations (RSDs) for five replicates were or =0.9991. Validation of the methodology was carried out by standard addition method at two concentration levels (0.25 and 1 ng g(-1)) and by comparing with a reference Soxhlet technique. Recovery values were > or =80%, which showed a satisfactory robustness of the analytical methodology for determination of low PBDEs concentration in sediment samples. Copyright 2010 Elsevier B.V. All rights reserved.

Verification and application of beam steering Phased Array UT technique for complex structures

International Nuclear Information System (INIS)

Yamamoto, Setsu; Miura, Takahiro; Semboshi, Jun; Ochiai, Makoto; Mitsuhashi, Tadahiro; Adachi, Hiroyuki; Yamamoto, Satoshi

2013-01-01

Phased Array Ultrasonic Testing (PAUT) techniques for complex geometries are greatly progressing. We developed an immersion PAUT which is suitable for complex surface profiles such as nozzles and deformed welded areas. Furthermore, we have developed a shape adaptive beam steering technique for 3D complex surface structures with conventional array probe and flexible coupling gel which makes the immersion beam forming technique usable under dry conditions. This system consists of 3 steps. Step1 is surface profile measurement which based on 3D Synthesis Aperture Focusing Technique (SAFT), Step2 is delay law calculation which could take into account the measured 3D surface profiles and steer a shape adjusted ultrasonic beam, Step3 is shape adjusted B-scope construction. In this paper, verification results of property of this PAUT system using R60 curved specimen and nozzle shaped specimen which simulated actual BWR structure. (author)

Heating and thermal control of brazing technique to break contamination path for potential Mars sample return

Science.gov (United States)

Bao, Xiaoqi; Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph; Campos, Sergio

2017-04-01

The potential return of Mars sample material is of great interest to the planetary science community, as it would enable extensive analysis of samples with highly sensitive laboratory instruments. It is important to make sure such a mission concept would not bring any living microbes, which may possibly exist on Mars, back to Earth's environment. In order to ensure the isolation of Mars microbes from Earth's Atmosphere, a brazing sealing and sterilizing technique was proposed to break the Mars-to-Earth contamination path. Effectively, heating the brazing zone in high vacuum space and controlling the sample temperature for integrity are key challenges to the implementation of this technique. The break-thechain procedures for container configurations, which are being considered, were simulated by multi-physics finite element models. Different heating methods including induction and resistive/radiation were evaluated. The temperature profiles of Martian samples in a proposed container structure were predicted. The results show that the sealing and sterilizing process can be controlled such that the samples temperature is maintained below the level that may cause damage, and that the brazing technique is a feasible approach to breaking the contamination path.

Quantitative Phase Imaging Techniques for the Study of Cell Pathophysiology: From Principles to Applications

Directory of Open Access Journals (Sweden)

Hyunjoo Park

2013-03-01

Full Text Available A cellular-level study of the pathophysiology is crucial for understanding the mechanisms behind human diseases. Recent advances in quantitative phase imaging (QPI techniques show promises for the cellular-level understanding of the pathophysiology of diseases. To provide important insight on how the QPI techniques potentially improve the study of cell pathophysiology, here we present the principles of QPI and highlight some of the recent applications of QPI ranging from cell homeostasis to infectious diseases and cancer.

Texture investigation in aluminium and iron - silicon samples by neutron diffraction technique

International Nuclear Information System (INIS)

Pugliese, R.; Yamasaki, J.M.

1988-09-01

By means of the neutron diffraction technique the texture of 5% and 98% rolled-aluminium and of iron-silicon steel used in the core of electric transformers, have been determined. The measurements were performed by using a neutron diffractometer installed at the IEA-R1 Nuclear Research Reactor, in the Beam-Hole n 0 . 6. To avoid corrections such as neutron absorption and sample luminosity the geometric form of the samples were approximated to spheric or octagonal prism, and its dimensions do not exceed that of the neutron beam. The texture of the samples were analysed with the help of a computer programme that analyses the intensity of the diffracted neutron beam and plot the pole figures. (author) [pt

The particle analysis based on FT-TIMS technique for swipe sample under the frame of nuclear safeguard

International Nuclear Information System (INIS)

Yang Tianli; Liu Xuemei; Liu Zhao; Tang Lei; Long Kaiming

2008-06-01

Under the frame of nuclear safeguard, the particles analysis for swipe sample is an advance mean to detect the undeclared uranium enriched facilities and undeclared uranium enriched activity. The technique of particle analysis based on fission track-thermal ionization mass spectrometry (FT-TIMS) for swipe sample have been built. The reliability and the experimental background for selecting particles consisting of uranium from swipe sample by FT method have been verified. In addition, the utilization coefficient of particles on the surface of swipe sample have also been tested. These works have provided the technique support for application in the area of nuclear verification. (authors)

[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.

Characterization of mineral phases of agricultural soil samples of Colombian coffee using Mössbauer spectroscopy and X-ray diffraction

Science.gov (United States)

Rodríguez, Humberto Bustos; Lozano, Dagoberto Oyola; Martínez, Yebrayl Antonio Rojas; Pinilla, Marlene Rivera; Alcázar, German Antonio Pérez

2012-03-01

Soil chemical analysis, X-ray diffraction (XRD) and Mössbauer spectrometry (MS) of 57Fe were used to characterize mineral phases of samples taken from the productive layer (horizon A) of agricultural coffee soil from Tolima (Colombia). Chemical analysis shows the chemical and textural parameters of samples from two different regions of Tolima, i.e., Ibagué and Santa Isabel. By XRD phases like illite (I), andesine (A) and quartz (Q) in both samples were identified. The quantity of these phases is different for the two samples. The MS spectra taken at room temperature were adjusted by using five doublets, three of them associated to Fe + 3 type sites and the other two to Fe + 2 type sites. According to their isomer shift and quadrupole splitting the presence of phases like illite (detected by DRX), nontronite and biotite (not detected by XRD) can be postulated.

Characterization of mineral phases of agricultural soil samples of Colombian coffee using Mössbauer spectroscopy and X-ray diffraction

International Nuclear Information System (INIS)

Rodríguez, Humberto Bustos; Lozano, Dagoberto Oyola; Martínez, Yebrayl Antonio Rojas; Pinilla, Marlene Rivera; Alcázar, German Antonio Pérez

2012-01-01

Soil chemical analysis, X-ray diffraction (XRD) and Mössbauer spectrometry (MS) of 57 Fe were used to characterize mineral phases of samples taken from the productive layer (horizon A) of agricultural coffee soil from Tolima (Colombia). Chemical analysis shows the chemical and textural parameters of samples from two different regions of Tolima, i.e., Ibagué and Santa Isabel. By XRD phases like illite (I), andesine (A) and quartz (Q) in both samples were identified. The quantity of these phases is different for the two samples. The MS spectra taken at room temperature were adjusted by using five doublets, three of them associated to Fe  + 3 type sites and the other two to Fe  + 2 type sites. According to their isomer shift and quadrupole splitting the presence of phases like illite (detected by DRX), nontronite and biotite (not detected by XRD) can be postulated.

Inference in Complex Systems Using Multi-Phase MCMC Sampling With Gradient Matching Burn-in

OpenAIRE

Lazarus, Alan; Husmeier, Dirk; Papamarkou, Theodore

2017-01-01

We propose a novel method for parameter inference that builds on the current research in gradient matching surrogate likelihood spaces. Adopting a three phase technique, we demonstrate that it is possible to obtain parameter estimates of limited bias whilst still adopting the paradigm of the computationally cheap surrogate approximation.

Comparison of parasite loads in serum and blood samples from patients in acute and chronic phases of Chagas disease.

Science.gov (United States)

Hernández, Carolina; Teherán, Aníbal; Flórez, Carolina; Ramírez, Juan David

2018-04-17

Molecular methods have been developed for the detection and quantification of Trypanosoma cruzi DNA in blood samples from patients with Chagas disease. However, aspects of sample processing necessary for quantitative real-time PCR (qPCR), such as the addition of guanidine hydrochloride to whole blood samples, may limit timely access to molecular diagnosis. We analysed 169 samples from serum and guanidine-EDTA blood (GEB) obtained from patients in acute and chronic phases of Chagas disease. We applied qPCR targeted to the satellite DNA region. Finally, we compared the parasite loads and cycle of threshold values of the qPCR. The results confirmed the usefulness of serum samples for the detection and quantification of parasite DNA in patients with Chagas disease, especially in the acute phase. However, the parasite loads detected in serum samples from patients in the chronic phase were lower than those detected in GEB samples. The epidemiological implications of the findings are herein discussed.

Refinement of NMR structures using implicit solvent and advanced sampling techniques.

Science.gov (United States)

Chen, Jianhan; Im, Wonpil; Brooks, Charles L

2004-12-15

NMR biomolecular structure calculations exploit simulated annealing methods for conformational sampling and require a relatively high level of redundancy in the experimental restraints to determine quality three-dimensional structures. Recent advances in generalized Born (GB) implicit solvent models should make it possible to combine information from both experimental measurements and accurate empirical force fields to improve the quality of NMR-derived structures. In this paper, we study the influence of implicit solvent on the refinement of protein NMR structures and identify an optimal protocol of utilizing these improved force fields. To do so, we carry out structure refinement experiments for model proteins with published NMR structures using full NMR restraints and subsets of them. We also investigate the application of advanced sampling techniques to NMR structure refinement. Similar to the observations of Xia et al. (J.Biomol. NMR 2002, 22, 317-331), we find that the impact of implicit solvent is rather small when there is a sufficient number of experimental restraints (such as in the final stage of NMR structure determination), whether implicit solvent is used throughout the calculation or only in the final refinement step. The application of advanced sampling techniques also seems to have minimal impact in this case. However, when the experimental data are limited, we demonstrate that refinement with implicit solvent can substantially improve the quality of the structures. In particular, when combined with an advanced sampling technique, the replica exchange (REX) method, near-native structures can be rapidly moved toward the native basin. The REX method provides both enhanced sampling and automatic selection of the most native-like (lowest energy) structures. An optimal protocol based on our studies first generates an ensemble of initial structures that maximally satisfy the available experimental data with conventional NMR software using a simplified

Propagating Mixed Uncertainties in Cyber Attacker Payoffs: Exploration of Two-Phase Monte Carlo Sampling and Probability Bounds Analysis

Energy Technology Data Exchange (ETDEWEB)

Chatterjee, Samrat; Tipireddy, Ramakrishna; Oster, Matthew R.; Halappanavar, Mahantesh

2016-09-16

Securing cyber-systems on a continual basis against a multitude of adverse events is a challenging undertaking. Game-theoretic approaches, that model actions of strategic decision-makers, are increasingly being applied to address cybersecurity resource allocation challenges. Such game-based models account for multiple player actions and represent cyber attacker payoffs mostly as point utility estimates. Since a cyber-attacker’s payoff generation mechanism is largely unknown, appropriate representation and propagation of uncertainty is a critical task. In this paper we expand on prior work and focus on operationalizing the probabilistic uncertainty quantification framework, for a notional cyber system, through: 1) representation of uncertain attacker and system-related modeling variables as probability distributions and mathematical intervals, and 2) exploration of uncertainty propagation techniques including two-phase Monte Carlo sampling and probability bounds analysis.

Dosimetric characterization of BeO samples in alpha, beta and X radiation beams using luminescent techniques

International Nuclear Information System (INIS)

Groppo, Daniela Piai

2013-01-01

In the medical field, the ionizing radiation is used both for therapeutic and diagnostic purposes, in a wide range of radiation doses. In order to ensure that the objective is achieved in practice, detailed studies of detectors and devices in different types of radiations beams are necessary. In this work a dosimetric characterization of BeO samples was performed using the techniques of thermoluminescence (TL) and optically stimulated luminescence (OSL) by a comparison of their response for alpha, beta and X radiations and the establishment of an appropriated system for use in monitoring of these radiations beams. The main results are: the high sensitivity to beta radiation for both techniques, good reproducibility of TL and OSL response (coefficients of variation lower than 5%), maximum energy dependence of the X radiation of 28% for the TL technique, and only 7% for the OSL technique, within the studied energy range. The dosimetric characteristics obtained in this work show the possibility of applying BeO samples to dosimetry of alpha, beta and X radiations, considering the studied dose ranges, using the TL and OSL techniques. From the results obtained, the samples of BeO showed their potential use for beam dosimetry in diagnostic radiology and radiotherapy. (author)

Second phase in steel AISI 316 tested at 8000C

International Nuclear Information System (INIS)

Silveira, V.L.A.; Monteiro, S.N.

The nature of second phases in type 316 stainless steel samples tested in creep to rupture at 800 0 C has been discussed. These phases were identified by experimental techniques completed with the available information in the literature. The role of these phases in the creep properties of the type 316 steel at 800 0 C is analysed [pt

Real-time interferometer phase detection using an LSI-11 microcomputer and high-speed digital techniques

International Nuclear Information System (INIS)

Mendell, D.S.

1978-01-01

This paper describes the basic design and philosophy of a real-time, interferometer phase-detection system used on the 2XIIB and TMX magnetic-fusion experiments at the Lawrence Livermore Laboratory. This diagnostics system is now a satellite to a host computer and uses high-speed, emitter-coupled logic techniques to derive data on real-time phase relationships. The system's input signals can be derived from interferometer outputs over a wide range of reference frequencies. An LSI-11 microcomputer is the interface between the high-speed phase-detection logic, buffer memory, human interaction, and host computer. Phase data on a storage CRT is immediately displayed after each experimental fusion shot. An operator can interrogate this phase data more closely from an interactive control panel, while the host computer is simultaneously examining the system's buffer memory or arming the system for the next shot

A dynamic plasmonic manipulation technique assisted by phase modulation of an incident optical vortex beam

International Nuclear Information System (INIS)

Yuan, G H; Wang, Q; Tan, P S; Lin, J; Yuan, X-C

2012-01-01

A novel phase modulation method for dynamic manipulation of surface plasmon polaritons (SPPs) with a phase engineered optical vortex (OV) beam illuminating on nanoslits is experimentally demonstrated. Because of the unique helical phase carried by an OV beam, dynamic control of SPP multiple focusing and standing wave generation is realized by changing the OV beam’s topological charge constituent with the help of a liquid-crystal spatial light modulator. Measurement of SPP distributions with near-field scanning optical microscopy showed an excellent agreement with numerical predictions. The proposed phase modulation technique for manipulating SPPs features has seemingly dynamic and reconfigurable advantages, with profound potential for development of SPP coupling, routing, multiplexing and high-resolution imaging devices on plasmonic chips. (paper)

Long-term monitoring of the Danube river-Sampling techniques, radionuclide metrology and radioecological assessment

International Nuclear Information System (INIS)

Maringer, F.J.; Gruber, V.; Hrachowitz, M.; Baumgartner, A.; Weilner, S.; Seidel, C.

2009-01-01

Sampling techniques and radiometric methods, developed and applied in a comprehensive radioecological study of the Danube River are presented. Results and radiometric data of sediment samples, collected by sediment traps in Austria and additionally by grab sampling in the Danube during research cruises between Germany and the delta (Black sea) are shown and discussed. Goal of the investigation is the protection of public and environment, especially the sustainable use and conservation of human freshwater resources against harmful radioactive exposure.

Multi-phase classification by a least-squares support vector machine approach in tomography images of geological samples

Science.gov (United States)

Khan, Faisal; Enzmann, Frieder; Kersten, Michael

2016-03-01

Image processing of X-ray-computed polychromatic cone-beam micro-tomography (μXCT) data of geological samples mainly involves artefact reduction and phase segmentation. For the former, the main beam-hardening (BH) artefact is removed by applying a best-fit quadratic surface algorithm to a given image data set (reconstructed slice), which minimizes the BH offsets of the attenuation data points from that surface. A Matlab code for this approach is provided in the Appendix. The final BH-corrected image is extracted from the residual data or from the difference between the surface elevation values and the original grey-scale values. For the segmentation, we propose a novel least-squares support vector machine (LS-SVM, an algorithm for pixel-based multi-phase classification) approach. A receiver operating characteristic (ROC) analysis was performed on BH-corrected and uncorrected samples to show that BH correction is in fact an important prerequisite for accurate multi-phase classification. The combination of the two approaches was thus used to classify successfully three different more or less complex multi-phase rock core samples.

An introduction to the technique of combined ion mobility spectrometry-mass spectrometry for the analysis of complex biological samples

International Nuclear Information System (INIS)

McDowall, Mark A.; Bateman, Robert H.; Bajic, Steve; Giles, Kevin; Langridge, Jim; McKenna, Therese; Pringle, Steven D.; Wildgoose, Jason L.

2008-01-01

Full Text: Ultra Performance Liquid Chromatography (UPLC) offers several advantages compared with conventional High Performance Liquid Chromatography (HPLC) as an 'inlet system' for mass spectrometry. UPLC provides improved chromatographic resolution, increased sensitivity and reduced analysis time. This is achieved through the use of sub 2μm particles (stationary phase) combined with high-pressure solvent delivery (up to 15,000 psi). When coupled with orthogonal acceleration time-of-flight (oa-TOF) mass spectrometry (MS), UPLC presents a means to achieve high sample throughput with reduced spectral overlap, increased sensitivity, and exact mass measurement capabilities with high mass spectral resolution (Ca 20,000 FWHM). Dispersive ion mobility spectrometry (IMS) implemented within a traveling-wave ion guide provides an orthogonal separation strategy for ions in the gas phase that can resolve isobaric ions formed by either Electrospray of MALDI ionization typically in Ca 20 mille seconds. All three techniques have the potential to be combined on-line (e.g. UPLC-IMS-MS/MS) in real time to maximize peak capacity and resolving power for the analysis of complex biological mixtures including; intact proteins, modified peptides and endogenous/exogenous metabolites

Qualification of final closure for disposal container II - applicability of TOFD and phased array technique for overpack welding

International Nuclear Information System (INIS)

Asano, H.; Kawahara, K.; Arakawa, T.; Kurokawa, M.

2002-01-01

With a focus on carbon steel, which is one of the candidate materials for the disposal container used in the geological disposal of high-level radioactive waste in Japan, the defect detection capabilities were examined regarding engineering defects of the TOFD technique, an ultrasonic testing method, and the phased array TOFD technique as non-destructive test techniques for the inspection of the weld of a carbon steel overpack. Regarding the TOFD technique, a measurement was conducted concerning the influence of the crossing angle of the ultrasonic beams on the capability of detect flaws, for examining the detection characteristics of the technique in relation to the lid structure of an overpack, and it was pointed out that it is appropriate to consider the lower tip of slit as the reference flaw. Based on the measurements and calculations regarding sound pressure distribution, projections about the scope covered by one test session were made and the optimum testing conditions were examined. Regarding the phased array TOFP technique, the detectability and quantification characteristics were investigated, and comparisons with those of the TOFD technique and the phased array UT technique were made. From the viewpoint of securing long-term corrosion resistance for an overpack, the ways of thinking for ensuring the quality and long-term integrity of the final sealing area of a disposal container were examined. This study stresses that identifying and defining the defects that are harmful to corrosion allowance is important as well as achieving improvements in the welding and testing techniques, and that the question to solve in particular from now on is how to establish effective means to detect defects on the weld surface and the near surface and how to approach the level of tolerance concerning the defects on and near the surface. (orig.)

Separation of arsenic species by capillary electrophoresis with sample-stacking techniques

Energy Technology Data Exchange (ETDEWEB)

Chen, Zu Liang; Naidu, Ravendra [Adelaide Laboratory, CSIRO Land and Water, PMB2, 5064, Glen Osmond, SA (Australia); Lin, Jin-Ming [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 100085, Beijing (China)

2003-03-01

A simple capillary zone electrophoresis procedure was developed for the separation of arsenic species (AsO{sub 2}{sup 2-}, AsO{sub 4}{sup 2-}, and dimethylarsinic acid, DMA). Both counter-electroosmotic and co-electroosmotic (EOF) modes were investigated for the separation of arsenic species with direct UV detection at 185 nm using 20 mmol L{sup -1} sodium phosphate as the electrolyte. The separation selectivity mainly depends on the separation modes and electrolyte pH. Inorganic anions (Cl{sup -}, NO{sub 2}{sup -}, NO{sub 3}{sup -} and SO{sub 4}{sup 2-}) presented in real samples did not interfere with arsenic speciation in either separation mode. To improve the detection limits, sample-stacking techniques, including large-volume sample stacking (LVSS) and field-amplified sample injection (FASI), were investigated for the preconcentration of As species in co-CZE mode. Less than 1 {mu}mol L{sup -1} of detection limits for As species were achieved using FASI. The proposed method was demonstrated for the separation and detection of As species in water. (orig.)

Decomposition and (importance) sampling techniques for multi-stage stochastic linear programs

Energy Technology Data Exchange (ETDEWEB)

Infanger, G.

1993-11-01

The difficulty of solving large-scale multi-stage stochastic linear programs arises from the sheer number of scenarios associated with numerous stochastic parameters. The number of scenarios grows exponentially with the number of stages and problems get easily out of hand even for very moderate numbers of stochastic parameters per stage. Our method combines dual (Benders) decomposition with Monte Carlo sampling techniques. We employ importance sampling to efficiently obtain accurate estimates of both expected future costs and gradients and right-hand sides of cuts. The method enables us to solve practical large-scale problems with many stages and numerous stochastic parameters per stage. We discuss the theory of sharing and adjusting cuts between different scenarios in a stage. We derive probabilistic lower and upper bounds, where we use importance path sampling for the upper bound estimation. Initial numerical results turned out to be promising.

Studies of matrix diffusion in gas phase

International Nuclear Information System (INIS)

Hartikainen, K.; Timonen, J.; Vaeaetaeinen, K.; Pietarila, H.

1994-03-01

The diffusion of solutes from fractures into rock matrix is an important factor in the safety analysis of disposal of radioactive waste. Laboratory measurements are needed to complement field investigations for a reliable determination of the necessary transport parameters. Measurements of diffusion coefficients in tight rock samples are usually time consuming because the diffusion processes are slow. On the other hand it is well known that diffusion coefficients in the gas phase are roughly four orders of magnitude larger than those in the liquid phase. Therefore, for samples whose structures do not change much upon drying, it is possible to estimate the diffusion properties of the liquid phase when the properties of the gas phase are known. Advantages of the gas method are quick and easy measurements. In the measurements nitrogen was used as the carrier gas and helium as the tracer gas, and standard techniques have been used for helium detection. Techniques have been developed for both channel flow and through-diffusion measurements. The breakthrough curves have been measured in every experiment and all measurements have been modelled by using appropriate analytical models. As a result matrix porosities and effective diffusion coefficients in the gas phase have been determined. (12 refs., 21 figs., 6 tabs.)

Prompt Gamma Activation Analysis (PGAA): Technique of choice for nondestructive bulk analysis of returned comet samples

International Nuclear Information System (INIS)

Lindstrom, D.J.; Lindstrom, R.M.

1989-01-01

Prompt gamma activation analysis (PGAA) is a well-developed analytical technique. The technique involves irradiation of samples in an external neutron beam from a nuclear reactor, with simultaneous counting of gamma rays produced in the sample by neutron capture. Capture of neutrons leads to excited nuclei which decay immediately with the emission of energetic gamma rays to the ground state. PGAA has several advantages over other techniques for the analysis of cometary materials: (1) It is nondestructive; (2) It can be used to determine abundances of a wide variety of elements, including most major and minor elements (Na, Mg, Al, Si, P, K, Ca, Ti, Cr, Mn, Fe, Co, Ni), volatiles (H, C, N, F, Cl, S), and some trace elements (those with high neutron capture cross sections, including B, Cd, Nd, Sm, and Gd); and (3) It is a true bulk analysis technique. Recent developments should improve the technique's sensitivity and accuracy considerably

Alternative sample-introduction technique to avoid breakthrough in gradient-elution liquid chromatography of polymers

NARCIS (Netherlands)

Reingruber, E.; Bedani, F.; Buchberger, W.; Schoenmakers, P.

2010-01-01

Gradient-elution liquid chromatography (GELC) is a powerful tool for the characterization of synthetic polymers. However, gradient-elution chromatograms often suffer from breakthrough phenomena. Breakthrough can be averted by using a sample solvent as weak as the mobile phase. However, this approach

An improved algorithm of image processing technique for film thickness measurement in a horizontal stratified gas-liquid two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Kuntoro, Hadiyan Yusuf, E-mail: hadiyan.y.kuntoro@mail.ugm.ac.id; Majid, Akmal Irfan; Deendarlianto, E-mail: deendarlianto@ugm.ac.id [Center for Energy Studies, Gadjah Mada University, Sekip K-1A Kampus UGM, Yogyakarta 55281 (Indonesia); Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika 2, Yogyakarta 55281 (Indonesia); Hudaya, Akhmad Zidni; Dinaryanto, Okto [Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika 2, Yogyakarta 55281 (Indonesia)

2016-06-03

Due to the importance of the two-phase flow researches for the industrial safety analysis, many researchers developed various methods and techniques to study the two-phase flow phenomena on the industrial cases, such as in the chemical, petroleum and nuclear industries cases. One of the developing methods and techniques is image processing technique. This technique is widely used in the two-phase flow researches due to the non-intrusive capability to process a lot of visualization data which are contain many complexities. Moreover, this technique allows to capture direct-visual information data of the flow which are difficult to be captured by other methods and techniques. The main objective of this paper is to present an improved algorithm of image processing technique from the preceding algorithm for the stratified flow cases. The present algorithm can measure the film thickness (h{sub L}) of stratified flow as well as the geometrical properties of the interfacial waves with lower processing time and random-access memory (RAM) usage than the preceding algorithm. Also, the measurement results are aimed to develop a high quality database of stratified flow which is scanty. In the present work, the measurement results had a satisfactory agreement with the previous works.

Calibrating passive sampling and passive dosing techniques to lipid based concentrations

DEFF Research Database (Denmark)

Mayer, Philipp; Schmidt, Stine Nørgaard; Annika, A.

2011-01-01

Equilibrium sampling into various formats of the silicone polydimethylsiloxane (PDMS) is increasingly used to measure the exposure of hydrophobic organic chemicals in environmental matrices, and passive dosing from silicone is increasingly used to control and maintain their exposure in laboratory...... coated vials and with Head Space Solid Phase Microextraction (HS-SPME) yielded lipid based concentrations that were in good agreement with each other, but about a factor of two higher than measured lipid-normalized concentrations in the organisms. Passive dosing was applied to bioconcentration...

Differential phase-contrast dark-field electron holography for strain mapping

Energy Technology Data Exchange (ETDEWEB)

Denneulin, Thibaud, E-mail: thibaud.denneulin@cemes.fr; Houdellier, Florent, E-mail: florent.houdellier@cemes.fr; Hÿtch, Martin, E-mail: martin.hytch@cemes.fr

2016-01-15

Strain mapping is an active area of research in transmission electron microscopy. Here we introduce a dark-field electron holographic technique that shares several aspects in common with both off-axis and in-line holography. Two incident and convergent plane waves are produced in front of the specimen thanks to an electrostatic biprism in the condenser system of a transmission electron microscope. The interference of electron beams diffracted by the illuminated crystal is then recorded in a defocused plane. The differential phase recovered from the hologram is directly proportional to the strain in the sample. The strain can be quantified if the separation of the images due to the defocus is precisely determined. The present technique has the advantage that the derivative of the phase is measured directly which allows us to avoid numerical differentiation. The distribution of the noise in the reconstructed strain maps is isotropic and more homogeneous. This technique was used to investigate different samples: a Si/SiGe superlattice, transistors with SiGe source/drain and epitaxial PZT thin films. - Highlights: • DPC dark-field electron holography is set up with a condenser biprism. • The DPC phase is directly proportional to the lattice deformation. • The technique is illustrated with epitaxial SiGe and Pb(Zr,Ti)O{sub 3} samples. • The defocus allows us to control the strain sensitivity and the spatial resolution. • A solution is proposed to setup this technique with a post-specimen biprism.