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Sample records for analytical techniques based

  1. Membrane-based microextraction techniques in analytical chemistry: A review.

    PubMed

    Carasek, Eduardo; Merib, Josias

    2015-06-23

    The use of membrane-based sample preparation techniques in analytical chemistry has gained growing attention from the scientific community since the development of miniaturized sample preparation procedures in the 1990s. The use of membranes makes the microextraction procedures more stable, allowing the determination of analytes in complex and "dirty" samples. This review describes some characteristics of classical membrane-based microextraction techniques (membrane-protected solid-phase microextraction, hollow-fiber liquid-phase microextraction and hollow-fiber renewal liquid membrane) as well as some alternative configurations (thin film and electromembrane extraction) used successfully for the determination of different analytes in a large variety of matrices, some critical points regarding each technique are highlighted.

  2. Chaos based Analytical techniques for daily extreme hydrological observations

    NASA Astrophysics Data System (ADS)

    Ng, W. W.; Panu, U. S.; Lennox, W. C.

    2007-08-01

    SummaryThe existence of outliers in data sets affects the decision-making process related to design, operation, and management of water resources. Insufficient information on outliers limits our understanding and predictive ability of such extreme hydrologic phenomena. Hydrologic systems are complex and dynamic in nature where current state and future evolutions depend on numerous physical variables and their interactions. Such systems can be represented in a simplified form through chaotic approach. Chaotic approach can determine the level of complexity of a system that provides the required information and parameters for subsequent predictive analyses. This research focuses on the application of chaotic analytical techniques to daily hydrologic series comprising of outliers. Different techniques and concepts of chaotic theory are adopted to enhance our understanding of the phenomena of outliers. Employing the streamflow data of the Saugeen River in Ontario, Canada, this paper illustrates the use of the autocorrelation functions, mutual information, power spectrum analysis, phase space reconstruction, correlation dimension, surrogate tests, and Hurst coefficients for the analysis of chaotic systems. Based on the results of analyses, one can arrive at the following conclusions: (1) The analyzed series exhibited random-like fluctuations. However, by rejecting the hypothesis of a random process, the analyzed series were found to be non-random. (2) The existence of outliers was found to increase the complexity of the analyzed series. High embedding dimensionalities obtained from the correlation analysis of the analyzed series support our conclusion. (3) The differentiation of a highly complex system from a random process, and the impact of outliers on the complexity of a system were quantitatively as well as visually presented from a chaotic perspective.

  3. Analytical techniques: A compilation

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A compilation, containing articles on a number of analytical techniques for quality control engineers and laboratory workers, is presented. Data cover techniques for testing electronic, mechanical, and optical systems, nondestructive testing techniques, and gas analysis techniques.

  4. A novel analytical approximation technique for highly nonlinear oscillators based on the energy balance method

    NASA Astrophysics Data System (ADS)

    Hosen, Md. Alal; Chowdhury, M. S. H.; Ali, Mohammad Yeakub; Ismail, Ahmad Faris

    In the present paper, a novel analytical approximation technique has been proposed based on the energy balance method (EBM) to obtain approximate periodic solutions for the focus generalized highly nonlinear oscillators. The expressions of the natural frequency-amplitude relationship are obtained using a novel analytical way. The accuracy of the proposed method is investigated on three benchmark oscillatory problems, namely, the simple relativistic oscillator, the stretched elastic wire oscillator (with a mass attached to its midpoint) and the Duffing-relativistic oscillator. For an initial oscillation amplitude A0 = 100, the maximal relative errors of natural frequency found in three oscillators are 2.1637%, 0.0001% and 1.201%, respectively, which are much lower than the errors found using the existing methods. It is highly remarkable that an excellent accuracy of the approximate natural frequency has been found which is valid for the whole range of large values of oscillation amplitude as compared with the exact ones. Very simple solution procedure and high accuracy that is found in three benchmark problems reveal the novelty, reliability and wider applicability of the proposed analytical approximation technique.

  5. Photoelectrochemical sensor for pentachlorophenol on microfluidic paper-based analytical device based on the molecular imprinting technique.

    PubMed

    Sun, Guoqiang; Wang, Panpan; Ge, Shenguang; Ge, Lei; Yu, Jinghua; Yan, Mei

    2014-06-15

    Combining microfluidic paper-based analytical device (μ-PAD) and the molecular imprinting technique, a visible light photoelectrochemical (PEC) sensing platform for the detection of pentachlorophenol (PCP) was established on gold nanoparticles (AuNPs) decorated paper working electrode using polypyrrole-functionalized ZnO nanoparticles. Ascorbic acid (AA) was exploited as an efficient and nontoxic electron donor for scavenging photogenerated holes under mild solution medium and facilitating the generation of stable photocurrent. The microfluidic molecular imprinted polymer-based PEC analytical origami device is developed for the detection of PCP in the linear range from 0.01 ng mL(-1) to 100 ng mL(-1) with a low detection limit of 4 pg mL(-1). This disposable microfluidic PEC origami device would provide a new platform for sensitive, specific, and multiplex assay in public health, environmental monitoring, and the developing world.

  6. Sensitivity analysis of laboratory based mine overburden analytical techniques for the prediction of acidic mine drainage. Final report

    SciTech Connect

    Bradham, W.S.; Caruccio, F.T.

    1995-09-01

    A three part sensitivity analysis was conducted to evaluate commonly used mine overburden analytical techniques. The primary objectives of the study were: identify and evaluate the effects of variability in mine overburden geochemistry, as measured by pyrite weight percent and neutralization potential (NP), on variability of contaminant production; determine which acid/base accounting interpretation technique best predicts both qualitative and quantitative leachate quality in laboratory analytical testing; and identify the predominant factors of weathering cells, soxhlet extraction, and column leaching tests, and evaluate variability of contaminant production due to variations in; storage conditions, leachant temperature, particle size, particle sorting efficiency, and leaching interval.

  7. A general, cryogenically-based analytical technique for the determination of trace quantities of volatile organic compounds in the atmosphere

    NASA Technical Reports Server (NTRS)

    Coleman, R. A.; Cofer, W. R., III; Edahl, R. A., Jr.

    1985-01-01

    An analytical technique for the determination of trace (sub-ppbv) quantities of volatile organic compounds in air was developed. A liquid nitrogen-cooled trap operated at reduced pressures in series with a Dupont Nafion-based drying tube and a gas chromatograph was utilized. The technique is capable of analyzing a variety of organic compounds, from simple alkanes to alcohols, while offering a high level of precision, peak sharpness, and sensitivity.

  8. Flexible microfluidic cloth-based analytical devices using a low-cost wax patterning technique.

    PubMed

    Nilghaz, Azadeh; Wicaksono, Dedy H B; Gustiono, Dwi; Abdul Majid, Fadzilah Adibah; Supriyanto, Eko; Abdul Kadir, Mohammed Rafiq

    2012-01-07

    This paper describes the fabrication of microfluidic cloth-based analytical devices (μCADs) using a simple wax patterning method on cotton cloth for performing colorimetric bioassays. Commercial cotton cloth fabric is proposed as a new inexpensive, lightweight, and flexible platform for fabricating two- (2D) and three-dimensional (3D) microfluidic systems. We demonstrated that the wicking property of the cotton microfluidic channel can be improved by scouring in soda ash (Na(2)CO(3)) solution which will remove the natural surface wax and expose the underlying texture of the cellulose fiber. After this treatment, we fabricated narrow hydrophilic channels with hydrophobic barriers made from patterned wax to define the 2D microfluidic devices. The designed pattern is carved on wax-impregnated paper, and subsequently transferred to attached cotton cloth by heat treatment. To further obtain 3D microfluidic devices having multiple layers of pattern, a single layer of wax patterned cloth can be folded along a predefined folding line and subsequently pressed using mechanical force. All the fabrication steps are simple and low cost since no special equipment is required. Diagnostic application of cloth-based devices is shown by the development of simple devices that wick and distribute microvolumes of simulated body fluids along the hydrophilic channels into reaction zones to react with analytical reagents. Colorimetric detection of bovine serum albumin (BSA) in artificial urine is carried out by direct visual observation of bromophenol blue (BPB) colour change in the reaction zones. Finally, we show the flexibility of the novel microfluidic platform by conducting a similar reaction in a bent pinned μCAD.

  9. ARPEFS as an analytic technique

    SciTech Connect

    Schach von Wittenau, A.E.

    1991-04-01

    Two modifications to the ARPEFS technique are introduced. These are studied using p(2 {times} 2)S/Cu(001) as a model system. The first modification is the obtaining of ARPEFS {chi}(k) curves at temperatures as low as our equipment will permit. While adding to the difficulty of the experiment, this modification is shown to almost double the signal-to-noise ratio of normal emission p(2 {times} 2)S/Cu(001) {chi}(k) curves. This is shown by visual comparison of the raw data and by the improved precision of the extracted structural parameters. The second change is the replacement of manual fitting of the Fourier filtered {chi}(k) curves by the use of the simplex algorithm for parameter determination. Again using p(2 {times} 2)S/Cu(001) data, this is shown to result in better agreement between experimental {chi}(k) curves and curves calculated based on model structures. The improved ARPEFS is then applied to p(2 {times} 2)S/Ni(111) and ({radical}3 {times} {radical}3) R30{degree}S/Ni(111). For p(2 {times} 2)S/Cu(001) we find a S-Cu bond length of 2.26 {Angstrom}, with the S adatom 1.31 {Angstrom} above the fourfold hollow site. The second Cu layer appears to be corrugated. Analysis of the p(2 {times} 2)S/Ni(111) data indicates that the S adatom adatom adsorbs onto the FCC threefold hollow site 1.53 {Angstrom} above the Ni surface. The S-Ni bond length is determined to be 2.13 {Angstrom}, indicating an outwards shift of the first layer Ni atoms. We are unable to assign a unique structure to ({radical}3 {times} {radical}3)R30{degree}S/Ni(111). An analysis of the strengths and weaknesses of ARPEFS as an experimental and analytic technique is presented, along with a summary of problems still to be addressed.

  10. Analytical chemistry: Principles and techniques

    SciTech Connect

    Hargis, L.G.

    1988-01-01

    Although this text seems to have been intended for use in a one-semester course in undergraduate analytical chemistry, it includes the range of topics usually encountered in a two-semester introductory course in chemical analysis. The material is arranged logically for use in a two-semester course: the first 12 chapters contain the subjects most often covered in the first term, and the next 10 chapters pertain to the second (instrumental) term. Overall breadth and level of treatment are standards for an undergraduate text of this sort, and the only major omission is that of kinetic methods (which is a common omission in analytical texts). In the first 12 chapters coverage of the basic material is quite good. The emphasis on the underlying principles of the techniques rather than on specifics and design of instrumentation is welcomed. This text may be more useful for the instrumental portion of an analytical chemistry course than for the solution chemistry segment. The instrumental analysis portion is appropriate for an introductory textbook.

  11. Cost and schedule analytical techniques development

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This contract provided technical services and products to the Marshall Space Flight Center's Engineering Cost Office (PP03) and the Program Plans and Requirements Office (PP02) for the period of 3 Aug. 1991 - 30 Nov. 1994. Accomplishments summarized cover the REDSTAR data base, NASCOM hard copy data base, NASCOM automated data base, NASCOM cost model, complexity generators, program planning, schedules, NASA computer connectivity, other analytical techniques, and special project support.

  12. Quantitative elemental analysis of an industrial mineral talc, using accelerator-based analytical technique

    NASA Astrophysics Data System (ADS)

    Olabanji, S. O.; Ige, A. O.; Mazzoli, C.; Ceccato, D.; Ajayi, E. O. B.; De Poli, M.; Moschini, G.

    2005-10-01

    Accelerator-based technique of PIXE was employed for the determination of the elemental concentration of an industrial mineral, talc. Talc is a very versatile mineral in industries with several applications. Due to this, there is a need to know its constituents to ensure that the workers are not exposed to health risks. Besides, microscopic tests on some talc samples in Nigeria confirm that they fall within the BP British Pharmacopoeia standard for tablet formation. However, for these samples to become a local source of raw material for pharmaceutical grade talc, the precise elemental compositions should be established which is the focus of this work. Proton beam produced by the 2.5 MV AN 2000 Van de Graaff accelerator at INFN, LNL, Legnaro, Padova, Italy was used for the PIXE measurements. The results which show the concentration of different elements in the talc samples, their health implications and metabolic roles are presented and discussed.

  13. Hyphenated analytical techniques for materials characterisation

    NASA Astrophysics Data System (ADS)

    Armstrong, Gordon; Kailas, Lekshmi

    2017-09-01

    This topical review will provide a survey of the current state of the art in ‘hyphenated’ techniques for characterisation of bulk materials, surface, and interfaces, whereby two or more analytical methods investigating different properties are applied simultaneously to the same sample to better characterise the sample than can be achieved by conducting separate analyses in series using different instruments. It is intended for final year undergraduates and recent graduates, who may have some background knowledge of standard analytical techniques, but are not familiar with ‘hyphenated’ techniques or hybrid instrumentation. The review will begin by defining ‘complementary’, ‘hybrid’ and ‘hyphenated’ techniques, as there is not a broad consensus among analytical scientists as to what each term means. The motivating factors driving increased development of hyphenated analytical methods will also be discussed. This introduction will conclude with a brief discussion of gas chromatography-mass spectroscopy and energy dispersive x-ray analysis in electron microscopy as two examples, in the context that combining complementary techniques for chemical analysis were among the earliest examples of hyphenated characterisation methods. The emphasis of the main review will be on techniques which are sufficiently well-established that the instrumentation is commercially available, to examine physical properties including physical, mechanical, electrical and thermal, in addition to variations in composition, rather than methods solely to identify and quantify chemical species. Therefore, the proposed topical review will address three broad categories of techniques that the reader may expect to encounter in a well-equipped materials characterisation laboratory: microscopy based techniques, scanning probe-based techniques, and thermal analysis based techniques. Examples drawn from recent literature, and a concluding case study, will be used to explain the

  14. Accelerator-based analytical technique in the evaluation of some Nigeria’s natural minerals: Fluorite, tourmaline and topaz

    NASA Astrophysics Data System (ADS)

    Olabanji, S. O.; Ige, O. A.; Mazzoli, C.; Ceccato, D.; Akintunde, J. A.; De Poli, M.; Moschini, G.

    2005-10-01

    For the first time, the complementary accelerator-based analytical technique of PIXE and electron microprobe analysis (EMPA) were employed for the characterization of some Nigeria's natural minerals namely fluorite, tourmaline and topaz. These minerals occur in different areas in Nigeria. The minerals are mainly used as gemstones and for other scientific and technological applications and therefore are very important. There is need to characterize them to know the quality of these gemstones and update the geochemical data on them geared towards useful applications. PIXE analysis was carried out using the 1.8 MeV collimated proton beam from the 2.5 MV AN 2000 Van de Graaff accelerator at INFN, LNL, Legnaro, Padova, Italy. The novel results which show many elements at different concentrations in these minerals are presented and discussed.

  15. Novel Applications of Lanthanoides as Analytical or Diagnostic Tools in the Life Sciences by ICP-MS-based Techniques

    NASA Astrophysics Data System (ADS)

    Müller, Larissa; Traub, Heike; Jakubowski, Norbert

    2016-11-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is a well-established analytical method for multi-elemental analysis in particular for elements at trace and ultra-trace levels. It has found acceptance in various application areas during the last decade. ICP-MS is also more and more applied for detection in the life sciences. For these applications, ICP-MS excels by a high sensitivity, which is independent of the molecular structure of the analyte, a wide linear dynamic range and by excellent multi-element capabilities. Furthermore, methods based on ICP-MS offer simple quantification concepts, for which usually (liquid) standards are applied, low matrix effects compared to other conventional bioanalytical techniques, and relative limits of detection (LODs) in the low pg g-1 range and absolute LODs down to the attomol range. In this chapter, we focus on new applications where the multi-element capability of ICP-MS is used for detection of lanthanoides or rare earth elements, which are applied as elemental stains or tags of biomolecules and in particular of antibodies.

  16. Visual quantification of Hg on a microfluidic paper-based analytical device using distance-based detection technique

    NASA Astrophysics Data System (ADS)

    Cai, Longfei; Fang, Yanling; Mo, Yuanhui; Huang, Yongshi; Xu, Chunxiu; Zhang, Zhen; Wang, Maoxian

    2017-08-01

    We presented a distance-based detection method for visual quantification of mercury ions on a microfluidic paper-based analytical device (μPAD). Dithizone in NaOH solution was used as chromogenic reagent and deposited onto paper channel delimited by hydrophobic wax barrier. Reactions happened between mercury ions and dithizone to form an insoluble colored complex, producing colored precipitate on the paper channel. The length of colored precipitate could be readily measured using the printed ruler along each device. The length of precipitate increase linearly with the mercury concentrations, mercury in sample solution could be quantified by measuring the length of the colored precipitate. Being free of any electronic instruments, this method has the advantages of portability, ease of use, low cost and disposability. This presented method was used to detect mercury ions in a synthetic sample, demonstrating its potential in on-site and real time analysis.

  17. Improved seismic risk estimation for Bucharest, based on multiple hazard scenarios, analytical methods and new techniques

    NASA Astrophysics Data System (ADS)

    Toma-Danila, Dragos; Florinela Manea, Elena; Ortanza Cioflan, Carmen

    2014-05-01

    Bucharest, capital of Romania (with 1678000 inhabitants in 2011), is one of the most exposed big cities in Europe to seismic damage. The major earthquakes affecting the city have their origin in the Vrancea region. The Vrancea intermediate-depth source generates, statistically, 2-3 shocks with moment magnitude >7.0 per century. Although the focal distance is greater than 170 km, the historical records (from the 1838, 1894, 1908, 1940 and 1977 events) reveal severe effects in the Bucharest area, e.g. intensities IX (MSK) for the case of 1940 event. During the 1977 earthquake, 1420 people were killed and 33 large buildings collapsed. The nowadays building stock is vulnerable both due to construction (material, age) and soil conditions (high amplification, generated within the weak consolidated Quaternary deposits, their thickness is varying 250-500m throughout the city). A number of 373 old buildings, out of 2563, evaluated by experts are more likely to experience severe damage/collapse in the next major earthquake. The total number of residential buildings, in 2011, was 113900. In order to guide the mitigation measures, different studies tried to estimate the seismic risk of Bucharest, in terms of buildings, population or economic damage probability. Unfortunately, most of them were based on incomplete sets of data, whether regarding the hazard or the building stock in detail. However, during the DACEA Project, the National Institute for Earth Physics, together with the Technical University of Civil Engineering Bucharest and NORSAR Institute managed to compile a database for buildings in southern Romania (according to the 1999 census), with 48 associated capacity and fragility curves. Until now, the developed real-time estimation system was not implemented for Bucharest. This paper presents more than an adaptation of this system to Bucharest; first, we analyze the previous seismic risk studies, from a SWOT perspective. This reveals that most of the studies don't use

  18. Analytical techniques for ambient sulfate aerosols

    SciTech Connect

    Johnson, S.A.; Graczyk, D.G.; Kumar, R.; Cunningham, P.T.

    1981-06-01

    Work done to further develop the infrared spectroscopic analytical method for the analysis of atmospheric aerosol particles, as well as some exploratory work on a new procedure for determining proton acidity in aerosol samples is described. Earlier work had led to the successful use of infrared (ir) spectrophotometry for the analysis of nitrate, ammonium, and neutral and acidic sulfates in aerosol samples collected by an impactor on a Mylar-film substrate. In this work, a filter-extraction method was developed to prepare filter-collected aerosol samples for ir analysis. A study was made comparing the ir analytical results on filter-collected samples with impactor-collected samples. Also, the infrared analytical technique was compared in field studies with light-scattering techniques for aerosol analysis. A highly sensitive instrument for aerosol analysis using attenuated total internal reflection (ATR) infrared spectroscopy was designed, built, and tested. This instrument provides a measurement sensitivity much greater (by a factor of 6 for SO/sub 4//sup 2 -/) than that obtainable using the KBr-pellet method. This instrument collect size- and time-resolved samples and is potentially capable of providing automated, near real-time aerosol analysis. Exploratory work on a novel approach to the determination of proton acidity in filter- or impactor-collected aerosol samples is also described. In this technique, the acidic sample is reacted with an access of a tagged, vapor-phase base. The unreacted base is flushed off and the amount of the tag retained by the sample is a direct measure of the proton acidity of the sample. The base was tagged with Ge, which can be conveniently determined by the x-ray fluorescence technique.

  19. Analytical Applications of Monte Carlo Techniques.

    ERIC Educational Resources Information Center

    Guell, Oscar A.; Holcombe, James A.

    1990-01-01

    Described are analytical applications of the theory of random processes, in particular solutions obtained by using statistical procedures known as Monte Carlo techniques. Supercomputer simulations, sampling, integration, ensemble, annealing, and explicit simulation are discussed. (CW)

  20. Analytical techniques for characterizing enzymatic biofuel cells.

    PubMed

    Moehlenbrock, Michael J; Arechederra, Robert L; Sjöholm, Kyle H; Minteer, Shelley D

    2009-12-01

    Enzymatic biofuel cells, which replace expensive metal catalysts with enzymes, are still in an early stage of development. This article details the analytical techniques that are often employed for evaluating and characterizing enzymatic biofuel cells and their corresponding bioanodes and biocathodes. (To listen to a podcast about this feature, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html.).

  1. Analytic technique: a reconsideration of the concept.

    PubMed

    Grossman, Lee

    2014-06-01

    Lipton's 1977 paper on "The Advantages of Freud's Technique …" is taken as a starting point to reconsider the concept of analytic technique itself. How an analyst works may be construed in terms of rules of the analyst's behavior, of principles underlying the analyst's behavior, or of the analyst's attitude that shapes how he or she acts on technical principles. The author argues that the analyst's attitude while acting on technical principles is an integral part of analytic praxis, and that it is a function of the analyst's character. As such, it is not generalizable as a "technique," yet it is often the case that an analyst will rationalize his or her character traits and think of them as a reproducible "technique." This has important consequences for teaching and supervising. The author suggests that the very idea of a reproducible analytic technique may inhibit the analyst's development of his or her own analytic voice. Other aspects of theorizing may also represent a conceptual confusion between what is personal and characterological and what is generalizable.

  2. Thermal Measurement Techniques in Analytical Microfluidic Devices

    PubMed Central

    Davaji, Benyamin; Lee, Chung Hoon

    2015-01-01

    Thermal measurement techniques have been used for many applications such as thermal characterization of materials and chemical reaction detection. Micromachining techniques allow reduction of the thermal mass of fabricated structures and introduce the possibility to perform high sensitivity thermal measurements in the micro-scale and nano-scale devices. Combining thermal measurement techniques with microfluidic devices allows performing different analytical measurements with low sample consumption and reduced measurement time by integrating the miniaturized system on a single chip. The procedures of thermal measurement techniques for particle detection, material characterization, and chemical detection are introduced in this paper. PMID:26066563

  3. Trace Analytical Techniques for Nuclear Forensics

    SciTech Connect

    Halverson, J.E.

    1999-04-28

    Over the history of the Savannah River Site, the Savannah River Technology Center (SRTC) has developed high sensitivity analytical capabilities in support of the Site's Environmental Monitoring Program and nuclear material protection process. Many of these techniques are applicable to the developing need for nuclear forensic analysis capabilities. Radiological and critically control procedures are in place at the SRTC, as well as clean room practices, to minimize the potential for a radiological evidentiary sample to contaminate personnel and the facility, as well as to minimize contaminating the sample thus rendering it useless by law enforcement agencies. Some of the trace analytical techniques available at the SRTC include ultra-low-level gamma and alpha spectrometry, high-sensitivity thermal ionization mass spectrometry, time-of-flight secondary ion mass spectrometry and trace organic analyses. These techniques have been tested during a planned domestic smuggling exercise and in the analysis of an unknown sample.In the event of an interdiction involving the illegal use or movement of radioactive material by U.S. law enforcement agencies (local, state or federal) forensic analyses will be used in developing and building a legal case against the perpetrators. The Savannah River Technology Center (SRTC) at the U.S. Department of Energy's Savannah River Site, a former nuclear production site currently conducting nuclear material stabilization missions, located in Aiken South Carolina, has a long history of performing trace analytical analyses for environmental monitoring. Many of these techniques are also applicable to nuclear forensic analyses. A summary of the trace analytical techniques used at the SRTC, which are applicable to Nuclear Forensics, is presented in this paper.Contamination control, of facilities and personnel involved in the analytical analyses, as well as preventing contamination of the sample, is a unique challenge for nuclear forensic analyses

  4. Examination of the capability of the laser-induced breakdown spectroscopy (LIBS) technique as the emerging laser-based analytical tool for analyzing trace elements in coal

    NASA Astrophysics Data System (ADS)

    Idris, N.; Ramli, M.; Mahidin, Hedwig, R.; Lie, Z. S.; Kurniawan, K. H.

    2014-09-01

    Due to its superior advantageous over the conventional analytical tools, laser-induced breakdown spectroscopy (LIBS) technique nowadays is becoming an emerging analytical tools and it is expected to be new future super star of analytical tool. This technique is based on the use of optical emission from the laser-induced plasma for analyzing spectrochemically the constituent and content of the sampled object. The capability of this technique is examined on analysis of trace elements in coal sample. Coal is one difficult sample to analyze due to its complex chemical composition and physical properties. It is inherent that coal contains trace element including heavy metal, thus mining, beneficiation and utilization poses hazard to environment and to human beings. The LIBS apparatus used was composed by a laser system (Nd-YAG: Quanta Ray; LAB SERIES; 1,064 nm; 500 mJ; 8 ns) and optical detector (McPherson model 2061; 1,000 mm focal length; f/8.6 Czerny-Turner) equipped with Andor I*Star intensified CCD 1024×256 pixels. The emitted laser was focused onto coal sample with a focusing lens of +250 mm. The plasma emission was collected by a fiber optics and sent to the the spectrograph. The coal samples were taken from Province of Aceh. As the results, several trace elements including heavy metal (As, Mn, Pb) can surely be observed, implying the eventuality of LIBS technique to analysis the presence of trace element in coal.

  5. Differentiation of lemon essential oil based on volatile and non-volatile fractions with various analytical techniques: a metabolomic approach.

    PubMed

    Mehl, Florence; Marti, Guillaume; Boccard, Julien; Debrus, Benjamin; Merle, Philippe; Delort, Estelle; Baroux, Lucie; Raymo, Vilfredo; Velazco, Maria Inés; Sommer, Horst; Wolfender, Jean-Luc; Rudaz, Serge

    2014-01-15

    Due to the importance of citrus lemon oil for the industry, fast and reliable analytical methods that allow the authentication and/or classification of such oil, using the origin of production or extraction process, are necessary. To evaluate the potential of volatile and non-volatile fractions for classification purposes, volatile compounds of cold-pressed lemon oils were analyzed, using GC-FID/MS and FT-MIR, while the non-volatile residues were studied, using FT-MIR, (1)H-NMR and UHPLC-TOF-MS. 64 Lemon oil samples from Argentina, Spain and Italy were considered. Unsupervised and supervised multivariate analyses were sequentially performed on various data blocks obtained by the above techniques. Successful data treatments led to statistically significant models that discriminated and classified cold-pressed lemon oils according to their geographic origin, as well as their production processes. Studying the loadings allowed highlighting of important classes of discriminant variables that corresponded to putative or identified chemical functions and compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Cost and Schedule Analytical Techniques Development

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This Final Report summarizes the activities performed by Science Applications International Corporation (SAIC) under contract NAS 8-40431 "Cost and Schedule Analytical Techniques Development Contract" (CSATD) during Option Year 3 (December 1, 1997 through November 30, 1998). This Final Report is in compliance with Paragraph 5 of Section F of the contract. This CSATD contract provides technical products and deliverables in the form of parametric models, databases, methodologies, studies, and analyses to the NASA Marshall Space Flight Center's (MSFC) Engineering Cost Office (PP03) and the Program Plans and Requirements Office (PP02) and other user organizations. Detailed Monthly Reports were submitted to MSFC in accordance with the contract's Statement of Work, Section IV "Reporting and Documentation". These reports spelled out each month's specific work performed, deliverables submitted, major meetings conducted, and other pertinent information. Therefore, this Final Report will summarize these activities at a higher level. During this contract Option Year, SAIC expended 25,745 hours in the performance of tasks called out in the Statement of Work. This represents approximately 14 full-time EPs. Included are the Huntsville-based team, plus SAIC specialists in San Diego, Ames Research Center, Tampa, and Colorado Springs performing specific tasks for which they are uniquely qualified.

  7. Optimization of Welding Parameters of Submerged Arc Welding Using Analytic Hierarchy Process (AHP) Based on Taguchi Technique

    NASA Astrophysics Data System (ADS)

    Sarkar, A.; Roy, J.; Majumder, A.; Saha, S. C.

    2014-04-01

    The present paper reports a new procedure using an analytic hierarchy process (AHP) based Taguchi method for the selection of the best welding parameters to fabricate submerged arc welding of plain carbon steel. Selection of best welding parameters is an unstructured decision problem involving process parameters for multiple weldments. In the present investigation, three process parameter variables i.e. wire feed rate (Wf), stick out (So) and traverse speed (Ts) and the three response parameters i.e. penetration, bead width and bead reinforcement have been considered. The objective of the present work is thus to improve the quality of the welded elements by using AHP analysis based Taguchi method. Taguchi L16 orthogonal array is used to perform with less number of experimental runs. Taguchi approach is insufficient to solve a multi response optimization problem. In order to overcome this limitation, a multi criteria decision making method, AHP is applied in the present study. The optimal condition to have a quality weld (i.e. bead geometry) is found at 210 mm/min of wire feed rate, 15 mm of stick out and 0.75 m/min of traverse speed and also observed that the effect of wire feed rate on the overall bead geometry properties is more significant than other welding parameters. Finally, a confirmatory test has been carried out to verify the optimal setting so obtained.

  8. An extraction technique for analytical sample preparation in aqueous solution based on controlling dispersion of ionic surfactant assemblies in isotachophoretic migration.

    PubMed

    Wang, Tianlin; Qin, Yexin; He, Haibo; Lv, Jun; Fan, Yong

    2011-01-07

    An extraction technique for analytical sample preparation in aqueous solution has been developed based on controlling dispersion of ionic surfactant assemblies. An extraction technique was realized based on controlling dispersion of the ionic surfactant assemblies in their isotachophoretic migration during the extraction by arranging the solutions of leading electrolyte, ionic surfactant and terminating electrolyte in order and applying voltage. Potential of the technique for analytical sample preparation in aqueous solution has been demonstrated by extracting a model sample of four alkylphenones, which were analyzed by HPLC after the extraction. The extraction showed concentration effects on all the four alkylphenones of butyrophenone, valerophenone, hexanophenone and heptanophenone in the model sample. The enrichment factors were 5.29, 7.70, 7.25 and 7.49 for the four alkylphenones of butyrophenone, valerophenone, hexanophenone and heptanophenone, respectively. Linear relationship was obtained with all the four alkylphenones between their chromatographic peak areas before and after the extraction in the range of concentration from 0.05 ppm to 1.5 ppm. The RSD of the chromatographic peak areas in triplicate extractions was 7.97%, 3.75%, 2.91% and 4.45% for butyrophenone, valerophenone, hexanophenone and heptanophenone, respectively. Advantages of the extraction technique developed include ease of operation, low reagent cost, no consumption of organic solvents and no requirement for additional phase separation.

  9. Electroextraction and electromembrane extraction: Advances in hyphenation to analytical techniques

    PubMed Central

    Oedit, Amar; Ramautar, Rawi; Hankemeier, Thomas

    2016-01-01

    Electroextraction (EE) and electromembrane extraction (EME) are sample preparation techniques that both require an electric field that is applied over a liquid‐liquid system, which enables the migration of charged analytes. Furthermore, both techniques are often used to pre‐concentrate analytes prior to analysis. In this review an overview is provided of the body of literature spanning April 2012–November 2015 concerning EE and EME, focused on hyphenation to analytical techniques. First, the theoretical aspects of concentration enhancement in EE and EME are discussed to explain extraction recovery and enrichment factor. Next, overviews are provided of the techniques based on their hyphenation to LC, GC, CE, and direct detection. These overviews cover the compounds and matrices, experimental aspects (i.e. donor volume, acceptor volume, extraction time, extraction voltage, and separation time) and the analytical aspects (i.e. limit of detection, enrichment factor, and extraction recovery). Techniques that were either hyphenated online to analytical techniques or show high potential with respect to online hyphenation are highlighted. Finally, the potential future directions of EE and EME are discussed. PMID:26864699

  10. Analytical detection techniques for droplet microfluidics--a review.

    PubMed

    Zhu, Ying; Fang, Qun

    2013-07-17

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

  11. Analytical decoupling techniques for fully implicit reservoir simulation

    NASA Astrophysics Data System (ADS)

    Qiao, Changhe; Wu, Shuhong; Xu, Jinchao; Zhang, Chen-Song

    2017-05-01

    This paper examines linear algebraic solvers for a given general purpose compositional simulator. In particular, the decoupling stage of the constraint pressure residual (CPR) preconditioner for linear systems arising from the fully implicit scheme is evaluated. An asymptotic analysis of the convergence behavior is given when Δt approaches zero. Based on this analysis, we propose an analytical decoupling technique, from which the pressure equation is directly related to an elliptic equation and can be solved efficiently. We show that this method ensures good convergence behavior of the algebraic solvers in a two-stage CPR-type preconditioner. We also propose a semi-analytical decoupling strategy that combines the analytical method and alternate block factorization method. Numerical experiments demonstrate the superior performance of the analytical and semi-analytical decoupling methods compared to existing methods.

  12. Comparison of four analytical techniques based on atomic spectrometry for the determination of total tin in canned foodstuffs.

    PubMed

    Boutakhrit, K; Crisci, M; Bolle, F; Van Loco, J

    2011-02-01

    Different techniques for the determination of total tin in beverages and canned foods by atomic spectrometry were compared. The performance characteristics of inductively coupled plasma-mass spectrometry (ICP-MS), hydride generation-inductively coupled plasma-atomic emission spectrometry (HG-ICP-AES), electrothermal atomisation-atomic absorption spectrometry (ETA-AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were determined in terms of linearity, precision, recovery, limit of detection, decision limit (CCα) and detection capability (CCβ) (Decision 2002/657/EC). Calibration ranges were covered from ng l⁻¹ to mg l⁻¹ level. Limits of detection that ranged from 0.01, 0.05, 2.0 to 200 µg l⁻¹ were reached for ICP-MS; HG-ICP-AES; ETA-AAS and ICP-AES, respectively. Precision, calculated according to ISO 5725-2 for repeatability and within-laboratory reproducibility and expressed as relative standard deviation (RSD), ranged from 1.6% to 4.9%; and recovery, based on Decision 2002/657/EC, was found to be between 95% and 110%. Procedures for the mineralisation or extraction of total tin were compared. Wet digestion, sequentially, with nitric acid and hydrogen peroxide provided the best results. The influence of possible interferences present in canned food and beverage was studied, but no interference in the determination of tin was observed. Since maximum levels for tin established by European Union legislation vary from 50 mg kg⁻¹ in canned baby foods and infant foods up to 200 mg kg⁻¹ in canned food, ICP-AES was chosen as the preferred technique for routine analysis thanks to its good precision, reliability and ease of use. The accuracy of this routine method was confirmed by participation in six proficiency test schemes with z-scores ranging from -1.9 to 0.6. Several canned foodstuffs and beverage samples from a local market were analysed with this technique.

  13. Analytical solutions of the QCD⊗QED DGLAP evolution equations based on the Mellin transform technique in NLO approximation

    NASA Astrophysics Data System (ADS)

    Mottaghizadeh, Marzieh; Taghavi Shahri, Fatemeh; Eslami, Parvin

    2017-10-01

    In this paper we present a new and efficient analytical solutions for evolving the QCD⊗QED DGLAP evolution equations in Mellin space and obtain the parton distribution functions (PDFs) in perturbative QCD including the QED corrections. The validity of our analytical solutions, which have done in the next to leading order QCD and the leading order QED approximations, are checked with the initial parton distributions from newly released CT14QED global analysis code (Schmidt et al., 2016 [9]). The evolved parton distribution functions are in good agreement with CT14QED PDFs set and also with those from APFEL (Bertone et al., 2014 [7]) program. Finally, we derived the impact of the NLO QED corrections to the QCD⊗QED DGLAP evolution equations.

  14. Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques.

    PubMed

    Zhu, Yumin; Zhang, Hua; Shao, Liming; He, Pinjing

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW). In this study, we investigated fine particles of <2mm, which are small fractions in MSW but constitute a significant component of the total heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of <10 μm within the fine particles. Zn-Cu, Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution. The overlapped enrichment, spatial association, and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products. Copyright © 2014. Published by Elsevier B.V.

  15. Accelerator-based analytical technique in the study of some anti-diabetic medicinal plants of Nigeria

    NASA Astrophysics Data System (ADS)

    Olabanji, S. O.; Omobuwajo, O. R.; Ceccato, D.; Adebajo, A. C.; Buoso, M. C.; Moschini, G.

    2008-05-01

    Diabetes mellitus, a clinical syndrome characterized by hyperglycemia due to deficiency of insulin, is a disease involving the endocrine pancreas and causes considerable morbidity and mortality in the world. In Nigeria, many plants, especially those implicated in herbal recipes for the treatment of diabetes, have not been screened for their elemental constituents while information on phytochemistry of some of them is not available. There is therefore the need to document these constituents as some of these plants are becoming increasingly important as herbal drugs or food additives. The accelerator-based technique PIXE, using the 1.8 MeV collimated proton beam from the 2.5 MV AN 2000 Van de Graaff accelerator at INFN, LNL, Legnaro (Padova) Italy, was employed in the determination of the elemental constituents of these anti-diabetic medicinal plants. Leaves of Gardenia ternifolia, Caesalpina pulcherrima, Solemostenon monostachys, whole plant of Momordica charantia and leaf and stem bark of Hunteria umbellata could be taken as vegetables, neutraceuticals, food additives and supplements in the management of diabetes. However, Hexabolus monopetalus root should be used under prescription.

  16. Analytical techniques for determining bound ammonium

    SciTech Connect

    Altaner, S.P.; Krohn, M.D

    1985-01-01

    Ammonium (NH/sub 4//sup +/) has been found to substitute for alkali cations in feldspars, micas, smectites, and alunites several Hg/Au-bearing hot springs deposits and volcanogenic stratabound Pb/Zn deposits. The authors compared four analytical techniques for determining the NH/sub 4//sup +/ content in rocks from these types of deposit and in synthetic NH/sub 4//sup +/-bearing feldspars, micas, and alunites: 1) X-ray diffraction (XRD), 2) mid- and 3) near-infrared spectroscopy (MIR and NIR) and 4) ion chromatography (IC). MIR analysis of synthetic minerals indicates that 7 ..mu..m band depth depends upon mineral type but that, for a given mineral, band depth is directly proportional to NH/sub 4//sup +/ concentration. NIR reflectance spectroscopy gives a rapid qualitative determination of NH/sub 4//sup +/ and allows positive field identification of NH/sub 4//sup +/. 4) IC gives a measure of the percent of NH/sub 4//sup +/ substitution by determining NH/sub 4//sup +/, K/sup +/, and Na/sup +/ concentrations. The procedure involves sample dissolution by HCl and HF in a microwave oven followed by separation and detection by an ion chromatograph. They estimate the detection limits of these analytical techniques for NH/sub 4//sup +/ concentration to be: XRD, 10-20% NH/sub 4//sup +/; MIR, 1-5% NG/sub 4//sup +/; and IC, <1% NH/sub 4//sup +/. Determination of NH/sub 4//sup +/ abundance in rocks will help to delineate the relationship of NH/sub 4//sup +/-bearing minerals to mineralization in ore deposits and promises to be an excellent method for prospecting.

  17. 40 CFR 141.27 - Alternate analytical techniques.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Alternate analytical techniques. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Monitoring and Analytical Requirements § 141.27 Alternate analytical techniques. (a) With the written permission of the State, concurred in...

  18. 40 CFR 141.27 - Alternate analytical techniques.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Alternate analytical techniques. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Monitoring and Analytical Requirements § 141.27 Alternate analytical techniques. (a) With the written permission of the State, concurred in by...

  19. Analytical Electrochemistry: Methodology and Applications of Dynamic Techniques.

    ERIC Educational Resources Information Center

    Heineman, William R.; Kissinger, Peter T.

    1980-01-01

    Reports developments involving the experimental aspects of finite and current analytical electrochemistry including electrode materials (97 cited references), hydrodynamic techniques (56), spectroelectrochemistry (62), stripping voltammetry (70), voltammetric techniques (27), polarographic techniques (59), and miscellany (12). (CS)

  20. Analytical Electrochemistry: Methodology and Applications of Dynamic Techniques.

    ERIC Educational Resources Information Center

    Heineman, William R.; Kissinger, Peter T.

    1980-01-01

    Reports developments involving the experimental aspects of finite and current analytical electrochemistry including electrode materials (97 cited references), hydrodynamic techniques (56), spectroelectrochemistry (62), stripping voltammetry (70), voltammetric techniques (27), polarographic techniques (59), and miscellany (12). (CS)

  1. 40 CFR 141.27 - Alternate analytical techniques.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....27 Section 141.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Monitoring and Analytical Requirements... analytical technique shall not decrease the frequency of monitoring required by this part. ...

  2. Rapid Non-Linear Uncertainty Propagation via Analytical Techniques

    NASA Astrophysics Data System (ADS)

    Fujimoto, K.; Scheeres, D. J.

    2012-09-01

    pdfs also enable the use of quadrature techniques in a Bayesian estimator for non-linear orbit determination and conjunction assessment. Finally, model parameter uncertainty, such as those for atmospheric drag, is readily implemented with little additional computational burden by adding the parameters in the state vector. To exemplify the speed and practicality of analytical techniques, we present two examples. First, numerically propagated Monte Carlo (MC) sample points from an initial Gaussian distribution are compared against the analytically propagated 3-sigma bounds of said distribution. The numerical simulation includes the J2 zonal harmonics of the Earth gravity field and atmospheric drag based on the NRLMSISE-00 density model. Conversely, the analytical model incorporates secular J2 effects and King-Hele's solution for objects influenced by drag. We find that the MC results match the analytically propagated bounds well, which is expected as probability must be constant over any given volume for deterministic systems. Next, the mean and covariance of an initial Gaussian distribution are propagated with, again, both MC and analytical methods. Not only are the analytical results a good approximation of the MC, the computation time is reduced by several orders of magnitude.

  3. Analytical techniques and instrumentation: A compilation. [analytical instrumentation, materials performance, and systems analysis

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Technical information is presented covering the areas of: (1) analytical instrumentation useful in the analysis of physical phenomena; (2) analytical techniques used to determine the performance of materials; and (3) systems and component analyses for design and quality control.

  4. Ancient mercury-based plating methods: combined use of surface analytical techniques for the study of manufacturing process and degradation phenomena.

    PubMed

    Ingo, Gabriel Maria; Guida, Giuseppe; Angelini, Emma; Di Carlo, Gabriella; Mezzi, Alessio; Padeletti, Giuseppina

    2013-11-19

    Fire gilding and silvering are age-old mercury-based processes used to coat thesurface of less precious substrates with thin layers of gold or silver. In ancient times, these methods were used to produce and decorate different types of artefacts, such as jewels, statues, amulets, and commonly-used objects. Gilders performed these processes not only to decorate objects but also to simulate the appearance of gold or silver, sometimes fraudulently. From a technological point of view, the aim of these workmen over 2000 years ago was to make the precious metal coatings as thin and adherent as possible. This was in order to save expensive metals and to improve the resistance to the wear caused by continued use and circulation. Without knowledge about the chemical-physical processes, the ancient crafts-men systematically manipulated these metals to create functional and decorative artistic objects. The mercury-based methods were also fraudulently used in ancient times to produce objects such as jewels and coins that looked like they were made of silver or gold but actually had a less precious core. These coins were minted by counterfeiters but also by the official issuing authorities. The latter was probably because of a lack of precious metals, reflecting periods of severe economic conditions. In this Account, we discuss some representative cases of gold- and silver-coatedobjects, focusing on unique and valuable Roman and Dark Ages period works of art, such as the St. Ambrogio's altar (825 AD), and commonly used objects. We carried out the investigations using surface analytical methods, such as selected area X-ray photoelectron spectroscopy and scanning electron microscopy combined with energy-dispersive spectroscopy. We used these methods to investigate the surface and subsurface chemical features of these important examples of art and technology, interpreting some aspects of the manufacturing methods and of disclosing degradation agents and mechanisms. These findings

  5. Analysis of Cultural Heritage by Accelerator Techniques and Analytical Imaging

    NASA Astrophysics Data System (ADS)

    Ide-Ektessabi, Ari; Toque, Jay Arre; Murayama, Yusuke

    2011-12-01

    In this paper we present the result of experimental investigation using two very important accelerator techniques: (1) synchrotron radiation XRF and XAFS; and (2) accelerator mass spectrometry and multispectral analytical imaging for the investigation of cultural heritage. We also want to introduce a complementary approach to the investigation of artworks which is noninvasive and nondestructive that can be applied in situ. Four major projects will be discussed to illustrate the potential applications of these accelerator and analytical imaging techniques: (1) investigation of Mongolian Textile (Genghis Khan and Kublai Khan Period) using XRF, AMS and electron microscopy; (2) XRF studies of pigments collected from Korean Buddhist paintings; (3) creating a database of elemental composition and spectral reflectance of more than 1000 Japanese pigments which have been used for traditional Japanese paintings; and (4) visible light-near infrared spectroscopy and multispectral imaging of degraded malachite and azurite. The XRF measurements of the Japanese and Korean pigments could be used to complement the results of pigment identification by analytical imaging through spectral reflectance reconstruction. On the other hand, analysis of the Mongolian textiles revealed that they were produced between 12th and 13th century. Elemental analysis of the samples showed that they contained traces of gold, copper, iron and titanium. Based on the age and trace elements in the samples, it was concluded that the textiles were produced during the height of power of the Mongol empire, which makes them a valuable cultural heritage. Finally, the analysis of the degraded and discolored malachite and azurite demonstrates how multispectral analytical imaging could be used to complement the results of high energy-based techniques.

  6. Analytical techniques for steroid estrogens in water samples - A review.

    PubMed

    Fang, Ting Yien; Praveena, Sarva Mangala; deBurbure, Claire; Aris, Ahmad Zaharin; Ismail, Sharifah Norkhadijah Syed; Rasdi, Irniza

    2016-12-01

    In recent years, environmental concerns over ultra-trace levels of steroid estrogens concentrations in water samples have increased because of their adverse effects on human and animal life. Special attention to the analytical techniques used to quantify steroid estrogens in water samples is therefore increasingly important. The objective of this review was to present an overview of both instrumental and non-instrumental analytical techniques available for the determination of steroid estrogens in water samples, evidencing their respective potential advantages and limitations using the Need, Approach, Benefit, and Competition (NABC) approach. The analytical techniques highlighted in this review were instrumental and non-instrumental analytical techniques namely gas chromatography mass spectrometry (GC-MS), liquid chromatography mass spectrometry (LC-MS), enzyme-linked immuno sorbent assay (ELISA), radio immuno assay (RIA), yeast estrogen screen (YES) assay, and human breast cancer cell line proliferation (E-screen) assay. The complexity of water samples and their low estrogenic concentrations necessitates the use of highly sensitive instrumental analytical techniques (GC-MS and LC-MS) and non-instrumental analytical techniques (ELISA, RIA, YES assay and E-screen assay) to quantify steroid estrogens. Both instrumental and non-instrumental analytical techniques have their own advantages and limitations. However, the non-instrumental ELISA analytical techniques, thanks to its lower detection limit and simplicity, its rapidity and cost-effectiveness, currently appears to be the most reliable for determining steroid estrogens in water samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Hybrid analytical technique for the nonlinear analysis of curved beams

    NASA Technical Reports Server (NTRS)

    Noor, A. K.; Andersen, C. M.

    1992-01-01

    The application of a two-step hybrid technique to the geometrically nonlinear analysis of curved beams is used to demonstrate the potential of hybrid analytical techniques in nonlinear structural mechanics. The hybrid technique is based on successive use of the perturbation method and a classical direct variational procedure. The functions associated with the various-order terms in the perturbation expansion of the fundamental unknowns, and their sensitivity derivatives with respect to material and geometric parameters of the beam, are first obtained by using the perturbation method. These functions are selected as coordinate functions (or modes) and the classical direct variational technique is then used to compute their amplitudes. The potential of the proposed hybrid technique for nonlinear analysis of structures is discussed. The effectiveness of the hybrid technique is demonstrated by means of numerical examples. The symbolic computation system Mathematica is used in the present study. The tasks performed on Mathematica include: (1) generation of algebraic expressions for the perturbation functions of the different response quantities and their sensitivity derivatives: and (2) determination of the radius of convergence of the perturbation series.

  8. Using Analytical Techniques to Interpret Financial Statements.

    ERIC Educational Resources Information Center

    Walters, Donald L.

    1986-01-01

    Summarizes techniques for interpreting the balance sheet and the statement of revenues, expenditures, and changes-in-fund-balance sections of the comprehensive annual financial report required of all school districts. Uses three tables to show intricacies involved and focuses on analyzing favorable and unfavorable budget variances. (MLH)

  9. 40 CFR 141.27 - Alternate analytical techniques.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Alternate analytical techniques. 141.27 Section 141.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Monitoring and Analytical Requirements...

  10. 40 CFR 141.27 - Alternate analytical techniques.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Alternate analytical techniques. 141.27 Section 141.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Monitoring and Analytical Requirements...

  11. Analytical Techniques for Tracking Filter Implementation

    DTIC Science & Technology

    1988-12-01

    Gholson and Moose 11977] outline two adaptive state estimation techniques. Both estimates incorporate a semi-Markov modeling process for the target model...representative of real world target maneuvers. Ricker and Williams [1978] take an approach that is similar to Gholson et. al. [1977,1979] where they develop...Electronic Systems, Vol AES- 11, No. 4, p. 675, July 1975. Gelb, Arthur, ed. Applied Optimal Estimation, M.I.T. Press, Cambridge, 1974. 182 Gholson , Norman

  12. Nuclear and Related Analytical Techniques for Environmental and Life Sciences

    SciTech Connect

    Frontasyeva, Marina

    2010-01-05

    The role of nuclear analytical techniques (NATs) in Environmental and Life Sciences is discussed. Examples of radioanalytical investigations at the IBR-2 pulsed fast reactor in Dubna illustrate the environmental, biomedical, geochemical and industrial applications of instrumental neutron activation analysis.

  13. A novel analytical technique suitable for the identification of plastics.

    PubMed

    Nečemer, Marijan; Kump, Peter; Sket, Primož; Plavec, Janez; Grdadolnik, Jože; Zvanut, Maja

    2013-01-01

    The enormous development and production of plastic materials in the last century resulted in increasing numbers of such kinds of objects. Development of a simple and fast technique to classify different types of plastics could be used in many activities dealing with plastic materials such as packaging of food, sorting of used plastic materials, and also, if technique would be non-destructive, for conservation of plastic artifacts in museum collections, a relatively new field of interest since 1990. In our previous paper we introduced a non-destructive technique for fast identification of unknown plastics based on EDXRF spectrometry,1 using as a case study some plastic artifacts archived in the Museum in order to show the advantages of the nondestructive identification of plastic material. In order to validate our technique it was necessary to apply for this purpose the comparison of analyses with some of the analytical techniques, which are more suitable and so far rather widely applied in identifying some most common sorts of plastic materials.

  14. Analytical evaluation of two motion washout techniques

    NASA Technical Reports Server (NTRS)

    Young, L. R.

    1977-01-01

    Practical tools were developed which extend the state of the art of moving base flight simulation for research and training purposes. The use of visual and vestibular cues to minimize the actual motion of the simulator itself was a primary consideration. The investigation consisted of optimum programming of motion cues based on a physiological model of the vestibular system to yield 'ideal washout logic' for any given simulator constraints.

  15. Deriving Earth Science Data Analytics Tools/Techniques Requirements

    NASA Astrophysics Data System (ADS)

    Kempler, S. J.

    2015-12-01

    Data Analytics applications have made successful strides in the business world where co-analyzing extremely large sets of independent variables have proven profitable. Today, most data analytics tools and techniques, sometimes applicable to Earth science, have targeted the business industry. In fact, the literature is nearly absent of discussion about Earth science data analytics. Earth science data analytics (ESDA) is the process of examining large amounts of data from a variety of sources to uncover hidden patterns, unknown correlations, and other useful information. ESDA is most often applied to data preparation, data reduction, and data analysis. Co-analysis of increasing number and volume of Earth science data has become more prevalent ushered by the plethora of Earth science data sources generated by US programs, international programs, field experiments, ground stations, and citizen scientists. Through work associated with the Earth Science Information Partners (ESIP) Federation, ESDA types have been defined in terms of data analytics end goals. Goals of which are very different than those in business, requiring different tools and techniques. A sampling of use cases have been collected and analyzed in terms of data analytics end goal types, volume, specialized processing, and other attributes. The goal of collecting these use cases is to be able to better understand and specify requirements for data analytics tools and techniques yet to be implemented. This presentation will describe the attributes and preliminary findings of ESDA use cases, as well as provide early analysis of data analytics tools/techniques requirements that would support specific ESDA type goals. Representative existing data analytics tools/techniques relevant to ESDA will also be addressed.

  16. Analytical Techniques for Predicting Grounded Ship Response.

    DTIC Science & Technology

    1983-09-01

    50) through (53) must always be tempered with the notion that the constants are average values based upon conventional hull forms . Moreover, they...accommodated within any number of existing portable computers with self-contained sources of power and that other forms of portable or shipboard computational...severely limited. The creation of local stresses sufficient to cause additional hull structural damage depends upon the magnitude of the ground reaction

  17. Cost and Schedule Analytical Techniques Development

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This Final Report summarizes the activities performed by Science Applications International Corporation (SAIC) for the base contract year from December 1, 1994 through November 30, 1995. The Final Report is in compliance with Paragraph 5 of Section F of the contract. This CSATD contract provides technical services and products to the NASA Marshall Space Flight Center's (MSFC) Engineering Cost Office (PP03) and the Program Plans and Requirements Office (PP02). Detailed Monthly Progress Reports were submitted to MSFC in accordance with the contract's Statement of Work Section IV "Reporting and Documentation". These reports spelled out each month's specific work accomplishments, deliverables submitted, major meetings held, and other pertinent information. This Final Report will summarize these activities at a higher level.

  18. Analytical techniques for assaying nitric oxide bioactivity.

    PubMed

    Jiang, Hong; Parthasarathy, Deepa; Torregrossa, Ashley C; Mian, Asad; Bryan, Nathan S

    2012-06-18

    GMP-independent effects of NO and are likely just as important physiologically as activation of sGC by NO. A true understanding of NO in physiology is derived from in vivo experiments sampling multiple compartments simultaneously. Nitric oxide (NO) methodology is a complex and often confusing science and the focus of many debates and discussion concerning NO biochemistry. The elucidation of new mechanisms and signaling pathways involving NO hinges on our ability to specifically, selectively and sensitively detect and quantify NO and all relevant NO products and metabolites in complex biological matrices. Here, we present a method for the rapid and sensitive analysis of nitrite and nitrate by HPLC as well as detection of free NO in biological samples using in vitro ozone based chemiluminescence with chemical derivitazation to determine molecular source of NO as well as ex vivo with organ bath myography.

  19. Waste minimization in analytical chemistry through innovative sample preparation techniques.

    SciTech Connect

    Smith, L. L.

    1998-05-28

    Because toxic solvents and other hazardous materials are commonly used in analytical methods, characterization procedures result in significant and costly amount of waste. We are developing alternative analytical methods in the radiological and organic areas to reduce the volume or form of the hazardous waste produced during sample analysis. For the radiological area, we have examined high-pressure, closed-vessel microwave digestion as a way to minimize waste from sample preparation operations. Heated solutions of strong mineral acids can be avoided for sample digestion by using the microwave approach. Because reactivity increases with pressure, we examined the use of less hazardous solvents to leach selected contaminants from soil for subsequent analysis. We demonstrated the feasibility of this approach by extracting plutonium from a NET reference material using citric and tartaric acids with microwave digestion. Analytical results were comparable to traditional digestion methods, while hazardous waste was reduced by a factor often. We also evaluated the suitability of other natural acids, determined the extraction performance on a wider variety of soil types, and examined the extraction efficiency of other contaminants. For the organic area, we examined ways to minimize the wastes associated with the determination of polychlorinated biphenyls (PCBs) in environmental samples. Conventional methods for analyzing semivolatile organic compounds are labor intensive and require copious amounts of hazardous solvents. For soil and sediment samples, we have a method to analyze PCBs that is based on microscale extraction using benign solvents (e.g., water or hexane). The extraction is performed at elevated temperatures in stainless steel cells containing the sample and solvent. Gas chromatography-mass spectrometry (GC/MS) was used to quantitate the analytes in the isolated extract. More recently, we developed a method utilizing solid-phase microextraction (SPME) for natural

  20. Analytic technique measures aromatics in soil and water

    SciTech Connect

    Roy, K.A.

    1990-12-01

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

  1. Authentication of Kalix (N.E. Sweden) vendace caviar using inductively coupled plasma-based analytical techniques: evaluation of different approaches.

    PubMed

    Rodushkin, I; Bergman, T; Douglas, G; Engström, E; Sörlin, D; Baxter, D C

    2007-02-05

    Different analytical approaches for origin differentiation between vendace and whitefish caviars from brackish- and freshwaters were tested using inductively coupled plasma double focusing sector field mass spectrometry (ICP-SFMS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). These approaches involve identifying differences in elemental concentrations or sample-specific isotopic composition (Sr and Os) variations. Concentrations of 72 elements were determined by ICP-SFMS following microwave-assisted digestion in vendace and whitefish caviar samples from Sweden (from both brackish and freshwater), Finland and USA, as well as in unprocessed vendace roe and salt used in caviar production. This data set allows identification of elements whose contents in caviar can be affected by salt addition as well as by contamination during production and packaging. Long-term method reproducibility was assessed for all analytes based on replicate caviar preparations/analyses and variations in element concentrations in caviar from different harvests were evaluated. The greatest utility for differentiation was demonstrated for elements with varying concentrations between brackish and freshwaters (e.g. As, Br, Sr). Elemental ratios, specifically Sr/Ca, Sr/Mg and Sr/Ba, are especially useful for authentication of vendace caviar processed from brackish water roe, due to the significant differences between caviar from different sources, limited between-harvest variations and relatively high concentrations in samples, allowing precise determination by modern analytical instrumentation. Variations in the 87Sr/86Sr ratio for vendace caviar from different harvests (on the order of 0.05-0.1%) is at least 10-fold less than differences between caviar processed from brackish and freshwater roe. Hence, Sr isotope ratio measurements (either by ICP-SFMS or by MC-ICP-MS) have great potential for origin differentiation. On the contrary, it was impossible to

  2. Non-destructive micro-analytical differentiation of copper pigments in paint layers of works of art using laboratory-based techniques.

    PubMed

    Svarcová, Silvie; Cermáková, Zdeňka; Hradilová, Janka; Bezdička, Petr; Hradil, David

    2014-11-11

    An unambiguous identification of pigments in paint layers of works of art forms a substantial part of the description of a painting technique, which is essential for the evaluation of the work of art including determination of the period and/or region of its creation as well as its attribution to a workshop or an author. Copper pigments represent a significant group of materials used in historic paintings. Because of their substantial diversity and, on the other hand, similarity, their identification and differentiation is a challenging task. An analytical procedure for unambiguous determination of both mineral-type (azurite, malachite, posnjakite, atacamite, etc.) and verdigris-type (copper acetates) copper pigments in the paint layers is presented, including light microscopy under VIS and UV light, electron microscopy with elemental microanalysis, Fourier transformed infrared micro-spectroscopy (micro-FTIR), and X-ray powder micro-diffraction (micro-XRD). Micro-Raman measurements were largely hindered by fluorescence. The choice of the analytical methods meets the contemporary requirement of a detailed description of various components in heterogeneous and minute samples of paint layers without their destruction. It is beneficial to use the combination of phase sensitive methods such as micro-FTIR and micro-XRD, because it allows the identification of both mineral-type and verdigris-type copper pigments in one paint layer. In addition, preliminary results concerning the study of the loss of crystallinity of verdigris-type pigments in proteinaceous binding media and the effect of lead white and lead tin yellow as highly absorbing matrix on verdigris identification in paint layers are reported.

  3. Non-destructive micro-analytical differentiation of copper pigments in paint layers of works of art using laboratory-based techniques

    NASA Astrophysics Data System (ADS)

    Švarcová, Silvie; Čermáková, Zdeňka; Hradilová, Janka; Bezdička, Petr; Hradil, David

    2014-11-01

    An unambiguous identification of pigments in paint layers of works of art forms a substantial part of the description of a painting technique, which is essential for the evaluation of the work of art including determination of the period and/or region of its creation as well as its attribution to a workshop or an author. Copper pigments represent a significant group of materials used in historic paintings. Because of their substantial diversity and, on the other hand, similarity, their identification and differentiation is a challenging task. An analytical procedure for unambiguous determination of both mineral-type (azurite, malachite, posnjakite, atacamite, etc.) and verdigris-type (copper acetates) copper pigments in the paint layers is presented, including light microscopy under VIS and UV light, electron microscopy with elemental microanalysis, Fourier transformed infrared micro-spectroscopy (micro-FTIR), and X-ray powder micro-diffraction (micro-XRD). Micro-Raman measurements were largely hindered by fluorescence. The choice of the analytical methods meets the contemporary requirement of a detailed description of various components in heterogeneous and minute samples of paint layers without their destruction. It is beneficial to use the combination of phase sensitive methods such as micro-FTIR and micro-XRD, because it allows the identification of both mineral-type and verdigris-type copper pigments in one paint layer. In addition, preliminary results concerning the study of the loss of crystallinity of verdigris-type pigments in proteinaceous binding media and the effect of lead white and lead tin yellow as highly absorbing matrix on verdigris identification in paint layers are reported.

  4. Analytical technique characterizes all trace contaminants in water

    NASA Technical Reports Server (NTRS)

    Foster, J. N.; Lysyj, I.; Nelson, K. H.

    1967-01-01

    Properly programmed combination of advanced chemical and physical analytical techniques characterize critically all trace contaminants in both the potable and waste water from the Apollo Command Module. This methodology can also be applied to the investigation of the source of water pollution.

  5. Analytical Techniques and Pharmacokinetics of Gastrodia elata Blume and Its Constituents.

    PubMed

    Wu, Jinyi; Wu, Bingchu; Tang, Chunlan; Zhao, Jinshun

    2017-07-08

    Gastrodia elata Blume (G. elata), commonly called Tianma in Chinese, is an important and notable traditional Chinese medicine (TCM), which has been used in China as an anticonvulsant, analgesic, sedative, anti-asthma, anti-immune drug since ancient times. The aim of this review is to provide an overview of the abundant efforts of scientists in developing analytical techniques and performing pharmacokinetic studies of G. elata and its constituents, including sample pretreatment methods, analytical techniques, absorption, distribution, metabolism, excretion (ADME) and influence factors to its pharmacokinetics. Based on the reported pharmacokinetic property data of G. elata and its constituents, it is hoped that more studies will focus on the development of rapid and sensitive analytical techniques, discovering new therapeutic uses and understanding the specific in vivo mechanisms of action of G. elata and its constituents from the pharmacokinetic viewpoint in the near future. The present review discusses analytical techniques and pharmacokinetics of G. elata and its constituents reported from 1985 onwards.

  6. New and emerging analytical techniques for marine biotechnology.

    PubMed

    Burgess, J Grant

    2012-02-01

    Marine biotechnology is the industrial, medical or environmental application of biological resources from the sea. Since the marine environment is the most biologically and chemically diverse habitat on the planet, marine biotechnology has, in recent years delivered a growing number of major therapeutic products, industrial and environmental applications and analytical tools. These range from the use of a snail toxin to develop a pain control drug, metabolites from a sea squirt to develop an anti-cancer therapeutic, and marine enzymes to remove bacterial biofilms. In addition, well known and broadly used analytical techniques are derived from marine molecules or enzymes, including green fluorescence protein gene tagging methods and heat resistant polymerases used in the polymerase chain reaction. Advances in bacterial identification, metabolic profiling and physical handling of cells are being revolutionised by techniques such as mass spectrometric analysis of bacterial proteins. Advances in instrumentation and a combination of these physical advances with progress in proteomics and bioinformatics are accelerating our ability to harness biology for commercial gain. Single cell Raman spectroscopy and microfluidics are two emerging techniques which are also discussed elsewhere in this issue. In this review, we provide a brief survey and update of the most powerful and rapidly growing analytical techniques as used in marine biotechnology, together with some promising examples of less well known earlier stage methods which may make a bigger impact in the future. Copyright © 2012. Published by Elsevier Ltd.

  7. Analytical results from ground-water sampling using a direct-push technique at the Dover National Test Site, Dover Air Force Base, Delaware, June-July 2001

    USGS Publications Warehouse

    Guertal, William R.; Stewart, Marie; Barbaro, Jeffrey R.; McHale, Timthoy J.

    2004-01-01

    A joint study by the Dover National Test Site and the U.S. Geological Survey was conducted from June 27 through July 18, 2001 to determine the spatial distribution of the gasoline oxygenate additive methyl tert-butyl ether and selected water-quality constituents in the surficial aquifer underlying the Dover National Test Site at Dover Air Force Base, Delaware. The study was conducted to support a planned enhanced bio-remediation demonstration and to assist the Dover National Test Site in identifying possible locations for future methyl tert-butyl ether remediation demonstrations. This report presents the analytical results from ground-water samples collected during the direct-push ground-water sampling study. A direct-push drill rig was used to quickly collect 115 ground-water samples over a large area at varying depths. The ground-water samples and associated quality-control samples were analyzed for volatile organic compounds and methyl tert-butyl ether by the Dover National Test Site analytical laboratory. Volatile organic compounds were above the method reporting limits in 59 of the 115 ground-water samples. The concentrations ranged from below detection limits to maximum values of 12.4 micrograms per liter of cis-1,2-dichloroethene, 1.14 micrograms per liter of trichloroethene, 2.65 micrograms per liter of tetrachloroethene, 1,070 micrograms per liter of methyl tert-butyl ether, 4.36 micrograms per liter of benzene, and 1.8 micrograms per liter of toluene. Vinyl chloride, ethylbenzene, p,m-xylene, and o-xylene were not detected in any of the samples collected during this investigation. Methyl tert-butyl ether was detected in 47 of the 115 ground-water samples. The highest methyl tert-butyl ether concentrations were found in the surficial aquifer from -4.6 to 6.4 feet mean sea level, however, methyl tert-butyl ether was detected as deep as -9.5 feet mean sea level. Increased methane concentrations and decreased dissolved oxygen concentrations were found in

  8. The analytical representation of viscoelastic material properties using optimization techniques

    NASA Technical Reports Server (NTRS)

    Hill, S. A.

    1993-01-01

    This report presents a technique to model viscoelastic material properties with a function of the form of the Prony series. Generally, the method employed to determine the function constants requires assuming values for the exponential constants of the function and then resolving the remaining constants through linear least-squares techniques. The technique presented here allows all the constants to be analytically determined through optimization techniques. This technique is employed in a computer program named PRONY and makes use of commercially available optimization tool developed by VMA Engineering, Inc. The PRONY program was utilized to compare the technique against previously determined models for solid rocket motor TP-H1148 propellant and V747-75 Viton fluoroelastomer. In both cases, the optimization technique generated functions that modeled the test data with at least an order of magnitude better correlation. This technique has demonstrated the capability to use small or large data sets and to use data sets that have uniformly or nonuniformly spaced data pairs. The reduction of experimental data to accurate mathematical models is a vital part of most scientific and engineering research. This technique of regression through optimization can be applied to other mathematical models that are difficult to fit to experimental data through traditional regression techniques.

  9. Applications of surface analytical techniques in Earth Sciences

    NASA Astrophysics Data System (ADS)

    Qian, Gujie; Li, Yubiao; Gerson, Andrea R.

    2015-03-01

    This review covers a wide range of surface analytical techniques: X-ray photoelectron spectroscopy (XPS), scanning photoelectron microscopy (SPEM), photoemission electron microscopy (PEEM), dynamic and static secondary ion mass spectroscopy (SIMS), electron backscatter diffraction (EBSD), atomic force microscopy (AFM). Others that are relatively less widely used but are also important to the Earth Sciences are also included: Auger electron spectroscopy (AES), low energy electron diffraction (LEED) and scanning tunnelling microscopy (STM). All these techniques probe only the very top sample surface layers (sub-nm to several tens of nm). In addition, we also present several other techniques i.e. Raman microspectroscopy, reflection infrared (IR) microspectroscopy and quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) that penetrate deeper into the sample, up to several μm, as all of them are fundamental analytical tools for the Earth Sciences. Grazing incidence synchrotron techniques, sensitive to surface measurements, are also briefly introduced at the end of this review. (Scanning) transmission electron microscopy (TEM/STEM) is a special case that can be applied to characterisation of mineralogical and geological sample surfaces. Since TEM/STEM is such an important technique for Earth Scientists, we have also included it to draw attention to the capability of TEM/STEM applied as a surface-equivalent tool. While this review presents most of the important techniques for the Earth Sciences, it is not an all-inclusive bibliography of those analytical techniques. Instead, for each technique that is discussed, we first give a very brief introduction about its principle and background, followed by a short section on approaches to sample preparation that are important for researchers to appreciate prior to the actual sample analysis. We then use examples from publications (and also some of our known unpublished results) within the Earth Sciences

  10. Multi-methodological investigation of kunzite, hiddenite, alexandrite, elbaite and topaz, based on laser-induced breakdown spectroscopy and conventional analytical techniques for supporting mineralogical characterization

    NASA Astrophysics Data System (ADS)

    Rossi, Manuela; Dell'Aglio, Marcella; De Giacomo, Alessandro; Gaudiuso, Rosalba; Senesi, Giorgio Saverio; De Pascale, Olga; Capitelli, Francesco; Nestola, Fabrizio; Ghiara, Maria Rosaria

    2014-02-01

    Gem-quality alexandrite, hiddenite and kunzite, elbaite and topaz minerals were characterized through a multi-methodological investigation based on EMPA-WDS, LA-ICP-MS, and laser-induced breakdown spectroscopy (LIBS). With respect to the others, the latter technique enables a simultaneous multi-elemental composition without any sample preparation and the detection of light elements, such as Li, Be and B. The criteria for the choice of minerals were: (a) the presence of chromophore elements in minor contents and/or as traces; (b) the presence of light lithophile elements (Li, Be and B); (c) different crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification and characterization of minerals, and as a fast screening method to determine the chemical composition, including the chromophore and light lithophile elements.

  11. Analytical techniques of pilot scanning behavior and their application

    NASA Technical Reports Server (NTRS)

    Harris, R. L., Sr.; Glover, B. J.; Spady, A. A., Jr.

    1986-01-01

    The state of the art of oculometric data analysis techniques and their applications in certain research areas such as pilot workload, information transfer provided by various display formats, crew role in automated systems, and pilot training are documented. These analytical techniques produce the following data: real-time viewing of the pilot's scanning behavior, average dwell times, dwell percentages, instrument transition paths, dwell histograms, and entropy rate measures. These types of data are discussed, and overviews of the experimental setup, data analysis techniques, and software are presented. A glossary of terms frequently used in pilot scanning behavior and a bibliography of reports on related research sponsored by NASA Langley Research Center are also presented.

  12. Analytical techniques for the evaluation of liquid protein therapeutics.

    PubMed

    Tatford, Owen C; Gomme, Peter T; Bertolini, Joseph

    2004-08-01

    A common problem in the manufacture of liquid protein therapeutics is the tendency for aggregation and particle formation on extended storage. Analytical techniques are required to study the propensity of solutions to form aggregates and particles and to allow the investigation of the effect of conditions encountered during manufacture and storage. A key challenge is to utilize appropriate specific and sensitive techniques to allow the early detection of initial aggregation events, thereby avoiding the need to resort to extended stability trials. The present review evaluates a range of techniques for the detection of changes in protein conformation and the formation of aggregates and particles. It is hoped that the availability of this information will encourage and facilitate studies to resolve stability issues associated with protein therapeutics.

  13. Development of Impurity Profiling Methods Using Modern Analytical Techniques.

    PubMed

    Ramachandra, Bondigalla

    2017-01-02

    This review gives a brief introduction about the process- and product-related impurities and emphasizes on the development of novel analytical methods for their determination. It describes the application of modern analytical techniques, particularly the ultra-performance liquid chromatography (UPLC), liquid chromatography-mass spectrometry (LC-MS), high-resolution mass spectrometry (HRMS), gas chromatography-mass spectrometry (GC-MS) and high-performance thin layer chromatography (HPTLC). In addition to that, the application of nuclear magnetic resonance (NMR) spectroscopy was also discussed for the characterization of impurities and degradation products. The significance of the quality, efficacy and safety of drug substances/products, including the source of impurities, kinds of impurities, adverse effects by the presence of impurities, quality control of impurities, necessity for the development of impurity profiling methods, identification of impurities and regulatory aspects has been discussed. Other important aspects that have been discussed are forced degradation studies and the development of stability indicating assay methods.

  14. Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.

    PubMed

    Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

    2013-12-20

    Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including practical applications of these techniques and a critical discussion about their advantages and disadvantages. The proposed solutions fulfill the requirements resulting from the concept of sustainable development, and specifically from the implementation of green chemistry principles in analytical laboratories. Therefore, particular attention was paid to the description of possible uses of novel, selective stationary phases in extraction techniques, inter alia, polymeric ionic liquids, carbon nanotubes, and silica- and carbon-based sorbents. The methodological solutions, together with properly matched sampling devices for collecting analytes from samples with varying matrix composition, enable us to reduce the number of errors during the sample preparation prior to chromatographic analysis as well as to limit the negative impact of this analytical step on the natural environment and the health of laboratory employees.

  15. Toward greener analytical techniques for the absolute quantification of peptides in pharmaceutical and biological samples.

    PubMed

    Van Eeckhaut, Ann; Mangelings, Debby

    2015-09-10

    Peptide-based biopharmaceuticals represent one of the fastest growing classes of new drug molecules. New reaction types included in the synthesis strategies to reduce the rapid metabolism of peptides, along with the availability of new formulation and delivery technologies, resulted in an increased marketing of peptide drug products. In this regard, the development of analytical methods for quantification of peptides in pharmaceutical and biological samples is of utmost importance. From the sample preparation step to their analysis by means of chromatographic or electrophoretic methods, many difficulties should be tackled to analyze them. Recent developments in analytical techniques emphasize more and more on the use of green analytical techniques. This review will discuss the progresses in and challenges observed during green analytical method development for the quantification of peptides in pharmaceutical and biological samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Application of metabonomic analytical techniques in the modernization and toxicology research of traditional Chinese medicine

    PubMed Central

    Lao, Yong-Min; Jiang, Jian-Guo; Yan, Lu

    2009-01-01

    In the recent years, a wide range of metabonomic analytical techniques are widely used in the modern research of traditional Chinese medicine (TCM). At the same time, the international community has attached increasing importance to TCM toxicity problems. Thus, many studies have been implemented to investigate the toxicity mechanisms of TCM. Among these studies, many metabonomic-based methods have been implemented to facilitate TCM toxicity investigation. At present, the most prevailing methods for TCM toxicity research are mainly single analysis techniques using only one analytical means. These techniques include nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS), etc.; with these techniques, some favourable outcomes have been gained in the toxic reaction studies of TCM, such as the action target organs assay, the establishment of action pattern, the elucidation of action mechanism and the exploration of action material foundation. However, every analytical technique has its advantages and drawbacks, no existing analytical technique can be versatile. Multi-analysed techniques can partially overcome the shortcomings of single-analysed techniques. Combination of GC-MS and LC-MS metabolic profiling approaches has unravelled the pathological outcomes of aristolochic acid-induced nephrotoxicity, which can not be achieved by single-analysed techniques. It is believed that with the further development of metabonomic analytical techniques, especially multi-analysed techniques, metabonomics will greatly promote TCM toxicity research and be beneficial to the modernization of TCM in terms of extending the application of modern means in the TCM safety assessment, assisting the formulation of TCM safety norms and establishing the international standards indicators. PMID:19508399

  17. Analytical techniques in lipidomics: state of the art.

    PubMed

    Jurowski, Kamil; Kochan, Kamila; Walczak, Justyna; Barańska, Małgorzata; Piekoszewski, Wojciech; Buszewski, Bogusław

    2017-03-24

    Current studies related to lipid identification and determination, or lipidomics in biological samples, are one of the most important issues in modern bioanalytical chemistry. There are many articles dedicated to specific analytical strategies used in lipidomics in various kinds of biological samples. However, in such literature, there is lack of articles dedicated to a comprehensive review of the actual analytical methodologies used in lipidomics. The aim of this article is to characterize the lipidomics methods used in modern bioanalysis according to the methodological point of view: 1) chromatography/separation methods, 2) spectroscopic methods and 3) mass spectrometry and also hyphenated methods. In the first part we discussed thin layer chromatography (TLC), high-pressure liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE). The second part includes spectroscopic techniques such as: Raman spectroscopy (RS), fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). The third part is a synthetic review of mass spectrometry, matrix-assisted laser desorption/ionization (MALDI), hyphenated methods, which include liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and also multidimensional techniques. Other aspects are the possibilities of the application of the described methods in lipidomics studies. Due to the fact that the exploration of new methods of lipidomics analysis and their applications in clinical and medical studies are still challenging for researchers working in life science, we hope that this review article will be very useful, for readers.

  18. Macro elemental analysis of food samples by nuclear analytical technique

    NASA Astrophysics Data System (ADS)

    Syahfitri, W. Y. N.; Kurniawati, S.; Adventini, N.; Damastuti, E.; Lestiani, D. D.

    2017-06-01

    Energy-dispersive X-ray fluorescence (EDXRF) spectrometry is a non-destructive, rapid, multi elemental, accurate, and environment friendly analysis compared with other detection methods. Thus, EDXRF spectrometry is applicable for food inspection. The macro elements calcium and potassium constitute important nutrients required by the human body for optimal physiological functions. Therefore, the determination of Ca and K content in various foods needs to be done. The aim of this work is to demonstrate the applicability of EDXRF for food analysis. The analytical performance of non-destructive EDXRF was compared with other analytical techniques; neutron activation analysis and atomic absorption spectrometry. Comparison of methods performed as cross checking results of the analysis and to overcome the limitations of the three methods. Analysis results showed that Ca found in food using EDXRF and AAS were not significantly different with p-value 0.9687, whereas p-value of K between EDXRF and NAA is 0.6575. The correlation between those results was also examined. The Pearson correlations for Ca and K were 0.9871 and 0.9558, respectively. Method validation using SRM NIST 1548a Typical Diet was also applied. The results showed good agreement between methods; therefore EDXRF method can be used as an alternative method for the determination of Ca and K in food samples.

  19. Speciation and Characterization of E-Waste, Using Analytical Techniques

    NASA Astrophysics Data System (ADS)

    López, C. Cortés; Cruz, V. E. Reyes; Rodríguez, M. A. Veloz; Ávila, J. Hernández; Badillo, J. Flores; Murcia, J. A. Cobos

    Electronic waste (e-waste), have a high potential as a source of precious metals, since they can contain metals like silver, gold, platinum, copper, zinc, nickel, tin and others. In this paper some e-waste were characterized using several analytical techniques as Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and inductively coupled plasma (ICP) in addition to the thermodynamic study by Pourbaix diagrams of silver (Ag), gold (Au), platinum (Pt), copper (Cu), nickel (Ni), tin (Sn) and zinc (Zn); considering an average low concentration of HNO3 (10% v/v). With results of the characterization was determined that the e-waste is an ideal source for the recovery of valuable metals. Similarly, the thermodynamic studies showed that it is possible to obtain all metallic species except Pt, in a potential window of 1.45V to 2.0V vs SCE.

  20. Web-based Visual Analytics for Extreme Scale Climate Science

    SciTech Connect

    Steed, Chad A; Evans, Katherine J; Harney, John F; Jewell, Brian C; Shipman, Galen M; Smith, Brian E; Thornton, Peter E; Williams, Dean N.

    2014-01-01

    In this paper, we introduce a Web-based visual analytics framework for democratizing advanced visualization and analysis capabilities pertinent to large-scale earth system simulations. We address significant limitations of present climate data analysis tools such as tightly coupled dependencies, ineffi- cient data movements, complex user interfaces, and static visualizations. Our Web-based visual analytics framework removes critical barriers to the widespread accessibility and adoption of advanced scientific techniques. Using distributed connections to back-end diagnostics, we minimize data movements and leverage HPC platforms. We also mitigate system dependency issues by employing a RESTful interface. Our framework embraces the visual analytics paradigm via new visual navigation techniques for hierarchical parameter spaces, multi-scale representations, and interactive spatio-temporal data mining methods that retain details. Although generalizable to other science domains, the current work focuses on improving exploratory analysis of large-scale Community Land Model (CLM) and Community Atmosphere Model (CAM) simulations.

  1. Analytical Techniques for the Study of Polyphenol-protein Interactions.

    PubMed

    Ulrih, Nataša Poklar

    2015-11-13

    This mini review focuses on advances in biophysical techniques to study polyphenol interactions with proteins. Polyphenols have many beneficial pharmacological properties, as a result of which they have been the subject of intensive studies. The most conventional techniques described here can be divided into three groups: (i) methods used for screening (in-situ methods); (ii) methods used to gain insight into the mechanisms of polyphenol-protein interactions; and (iii) methods used to study protein aggregation and precipitation. All of these methods used to study polyphenol-protein interactions are based on modifications to the physicochemical properties of the polyphenols or proteins after binding/ complex formation in solution. To date, numerous review articles have been published in the field of polyphenols. This review will give a brif insight in computational metods and biosensors and cell-based methods, spectroscopic methods including fluorescence emission, UV-vis adsorption, circular dichroism, Fourier transform infrared and mass spectrometry, nuclear magnetic resonance, X-ray diffraction, and light scattering techniqes including small-angle X-ray scattering and small-angle neutron scattering), and calorimetric techniques (isothermal titration calorimetry and differentiall scanning calorimetry), microscopy, the techniques which have been successfully used for polyphenol-protein interactions. At the end the new methods based on single molecule detection with high potential to study polyphenol-protein interactions will be presented. The advantages and disadvantages of each technique will be discussed as well as the thermodynamic, kinetic or structural parameters, which can be obtained. The other relevant biophysical experimental techniques that have proven to be valuable, such electrochemical methods, hydrodynamic techniques and chromatographic techniques will not be described here.

  2. Product identification techniques used as training aids for analytical chemists

    NASA Technical Reports Server (NTRS)

    Grillo, J. P.

    1968-01-01

    Laboratory staff assistants are trained to use data and observations of routine product analyses performed by experienced analytical chemists when analyzing compounds for potential toxic hazards. Commercial products are used as examples in teaching the analytical approach to unknowns.

  3. Enhancing simulation of efficiency with analytical tools. [combining computer simulation and analytical techniques for cost reduction

    NASA Technical Reports Server (NTRS)

    Seltzer, S. M.

    1974-01-01

    Some means of combining both computer simulation and anlytical techniques are indicated in order to mutually enhance their efficiency as design tools and to motivate those involved in engineering design to consider using such combinations. While the idea is not new, heavy reliance on computers often seems to overshadow the potential utility of analytical tools. Although the example used is drawn from the area of dynamics and control, the principles espoused are applicable to other fields. In the example the parameter plane stability analysis technique is described briefly and extended beyond that reported in the literature to increase its utility (through a simple set of recursive formulas) and its applicability (through the portrayal of the effect of varying the sampling period of the computer). The numerical values that were rapidly selected by analysis were found to be correct for the hybrid computer simulation for which they were needed. This obviated the need for cut-and-try methods to choose the numerical values, thereby saving both time and computer utilization.

  4. Aerodynamic measurement techniques. [laser based diagnostic techniques

    NASA Technical Reports Server (NTRS)

    Hunter, W. W., Jr.

    1976-01-01

    Laser characteristics of intensity, monochromatic, spatial coherence, and temporal coherence were developed to advance laser based diagnostic techniques for aerodynamic related research. Two broad categories of visualization and optical measurements were considered, and three techniques received significant attention. These are holography, laser velocimetry, and Raman scattering. Examples of the quantitative laser velocimeter and Raman scattering measurements of velocity, temperature, and density indicated the potential of these nonintrusive techniques.

  5. New analytical technique for carbon dioxide absorption solvents

    SciTech Connect

    Pouryousefi, F.; Idem, R.O.

    2008-02-15

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

  6. Applications of nuclear analytical techniques to environmental studies

    NASA Astrophysics Data System (ADS)

    Freitas, M. C.; Pacheco, A. M. G.; Marques, A. P.; Barros, L. I. C.; Reis, M. A.

    2001-07-01

    A few examples of application of nuclear-analytical techniques to biological monitors—natives and transplants—are given herein. Parmelia sulcata Taylor transplants were set up in a heavily industrialized area of Portugal—the Setúbal peninsula, about 50 km south of Lisbon—where indigenous lichens are rare. The whole area was 10×15 km around an oil-fired power station, and a 2.5×2.5 km grid was used. In north-western Portugal, native thalli of the same epiphytes (Parmelia spp., mostly Parmelia sulcata Taylor) and bark from olive trees (Olea europaea) were sampled across an area of 50×50 km, using a 10×10 km grid. This area is densely populated and features a blend of rural, urban-industrial and coastal environments, together with the country's second-largest metro area (Porto). All biomonitors have been analyzed by INAA and PIXE. Results were put through nonparametric tests and factor analysis for trend significance and emission sources, respectively.

  7. Advanced nuclear analytical and related techniques for the growing challenges in nanotoxicology.

    PubMed

    Chen, Chunying; Li, Yu-Feng; Qu, Ying; Chai, Zhifang; Zhao, Yuliang

    2013-11-07

    Manufactured nanomaterials with novel physicochemical properties are an important basis for nanosciences and related technologies. Nanotoxicology, aiming to understand the principles of interactions at the nano-bio interface and the relationship between the physicochemical properties of nanomaterials and their toxicological profiles, has become a new frontier in nanoscience. Nearly one decade of nanotoxicology research has shown that the interactions between nanomaterials and proteins, cells, animals, humans and the environment as well as the underlying mechanisms of toxicity for nanomaterials are remarkably complicated, requiring dedicated analytical methodology and tools. Because of their advantages of absolute quantification, high sensitivity, excellent accuracy and precision, low matrix effects and non-destructiveness, nuclear analytical techniques have been playing important roles in the study of nanotoxicology. A systematic summary and comprehensive review of the advanced nuclear analytical and related techniques in nanotoxicology is greatly needed. In this review article, we present a comprehensive overview of nuclear analytical techniques applied to the physicochemical characterization of nanomaterials, structural analysis of bio-nano interactions, visualization of nanomaterials in vitro, quantification of bio-distribution, bio-accumulation, and transformation of nanomaterials in vivo. As important complementary tools, optical imaging technologies are also highlighted. Future directions regarding advanced nuclear analytical approaches for nanotoxicology are also discussed. The rapid development of advanced light source-based techniques will enable new high-throughput screening techniques and provide high sensitivity with low detection limits, which are required for the distribution, imaging, and structural analysis of nanomaterials, and the molecular information of biomarkers for all aspects of nanotoxicology.

  8. Analytical techniques for mechanistic characterization of EUV photoresists

    NASA Astrophysics Data System (ADS)

    Grzeskowiak, Steven; Narasimhan, Amrit; Murphy, Michael; Ackerman, Christian; Kaminsky, Jake; Brainard, Robert L.; Denbeaux, Greg

    2017-03-01

    Extreme ultraviolet (EUV, 13.5 nm) lithography is the prospective technology for high volume manufacturing by the microelectronics industry. Significant strides towards achieving adequate EUV source power and availability have been made recently, but a limited rate of improvement in photoresist performance still delays the implementation of EUV. Many fundamental questions remain to be answered about the exposure mechanisms of even the relatively well understood chemically amplified EUV photoresists. Moreover, several groups around the world are developing revolutionary metal-based resists whose EUV exposure mechanisms are even less understood. Here, we describe several evaluation techniques to help elucidate mechanistic details of EUV exposure mechanisms of chemically amplified and metal-based resists. EUV absorption coefficients are determined experimentally by measuring the transmission through a resist coated on a silicon nitride membrane. Photochemistry can be evaluated by monitoring small outgassing reaction products to provide insight into photoacid generator or metal-based resist reactivity. Spectroscopic techniques such as thin-film Fourier transform infrared (FTIR) spectroscopy can measure the chemical state of a photoresist system pre- and post-EUV exposure. Additionally, electrolysis can be used to study the interaction between photoresist components and low energy electrons. Collectively, these techniques improve our current understanding of photomechanisms for several EUV photoresist systems, which is needed to develop new, better performing materials needed for high volume manufacturing.

  9. Economic Risk Analysis: Using Analytical and Monte Carlo Techniques.

    ERIC Educational Resources Information Center

    O'Donnell, Brendan R.; Hickner, Michael A.; Barna, Bruce A.

    2002-01-01

    Describes the development and instructional use of a Microsoft Excel spreadsheet template that facilitates analytical and Monte Carlo risk analysis of investment decisions. Discusses a variety of risk assessment methods followed by applications of the analytical and Monte Carlo methods. Uses a case study to illustrate use of the spreadsheet tool…

  10. Degradation of glass artifacts: application of modern surface analytical techniques.

    PubMed

    Melcher, Michael; Wiesinger, Rita; Schreiner, Manfred

    2010-06-15

    A detailed understanding of the stability of glasses toward liquid or atmospheric attack is of considerable importance for preserving numerous objects of our cultural heritage. Glasses produced in the ancient periods (Egyptian, Greek, or Roman glasses), as well as modern glass, can be classified as soda-lime-silica glasses. In contrast, potash was used as a flux in medieval Northern Europe for the production of window panes for churches and cathedrals. The particular chemical composition of these potash-lime-silica glasses (low in silica and rich in alkali and alkaline earth components), in combination with increased levels of acidifying gases (such as SO(2), CO(2), NO(x), or O(3)) and airborne particulate matter in today's urban or industrial atmospheres, has resulted in severe degradation of important cultural relics, particularly over the last century. Rapid developments in the fields of microelectronics and computer sciences, however, have contributed to the development of a variety of nondestructive, surface analytical techniques for the scientific investigation and material characterization of these unique and valuable objects. These methods include scanning electron microscopy in combination with energy- or wavelength-dispersive spectrometry (SEM/EDX or SEM/WDX), secondary ion mass spectrometry (SIMS), and atomic force microscopy (AFM). In this Account, we address glass analysis and weathering mechanisms, exploring the possibilities (and limitations) of modern analytical techniques. Corrosion by liquid substances is well investigated in the glass literature. In a tremendous number of case studies, the basic reaction between aqueous solutions and the glass surfaces was identified as an ion-exchange reaction between hydrogen-bearing species of the attacking liquid and the alkali and alkaline earth ions in the glass, causing a depletion of the latter in the outermost surface layers. Although mechanistic analogies to liquid corrosion are obvious, atmospheric

  11. Hybrid Analytical Technique for Nonlinear Vibration Analysis of Thin-Walled Beams

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Hadian, Jafar M.; Andersen, Carl M.

    1993-01-01

    A two-step hybrid analytical technique is presented for the nonlinear vibration analysis of thin-walled beams. The first step involves the generation of various-order perturbation functions using the Linstedt-Poincare perturbation technique. The second step consists of using the perturbation functions as coordinate (or approximation) functions and then computing both the amplitudes of these functions and the nonlinear frequency of vibration via a direct variational procedure. The analytical formulation is based on a form of the geometrically nonlinear beam theory with the effects of in-plane inertia, rotatory inertia, and transverse shear deformation included. The effectiveness of the proposed technique is demonstrated by means of a numerical example of thin-walled beam with a doubly symmetric I-section. The solutions obtained using a single-spatial mode were compared with those obtained using multiple-spatial modes. The standard of comparison was taken to be the frequencies obtained by the direct integration/fast Fourier transform (FFT) technique. The nonlinear frequencies obtained by the hybrid technique were shown to converge to the corresponding ones obtained by the direct integration/fast Fourier transform (FFT) technique well beyond the range of applicability of the perturbation technique. The frequencies and total strain energy of the beam were overestimated by using a single-spatial mode.

  12. Coal liquefaction process streams characterization and evaluation. Novel analytical techniques for coal liquefaction: Fluorescence microscopy

    SciTech Connect

    Rathbone, R.F.; Hower, J.C.; Derbyshire, F.J.

    1991-10-01

    This study demonstrated the feasibility of using fluorescence and reflectance microscopy techniques for the examination of distillation resid materials derived from direct coal liquefaction. Resid, as defined here, is the 850{degrees}F{sup +} portion of the process stream, and includes soluble organics, insoluble organics and ash. The technique can be used to determine the degree of hydrogenation and the presence of multiple phases occurring within a resid sample. It can also be used to infer resid reactivity. The technique is rapid, requiring less than one hour for sample preparation and examination, and thus has apparent usefulness for process monitoring. Additionally, the technique can distinguish differences in samples produced under various process conditions. It can, therefore, be considered a potentially useful technique for the process developer. Further development and application of this analytical method as a process development tool is justified based on these results.

  13. Recent Developments in the Speciation and Determination of Mercury Using Various Analytical Techniques

    PubMed Central

    Suvarapu, Lakshmi Narayana; Baek, Sung-Ok

    2015-01-01

    This paper reviews the speciation and determination of mercury by various analytical techniques such as atomic absorption spectrometry, voltammetry, inductively coupled plasma techniques, spectrophotometry, spectrofluorometry, high performance liquid chromatography, and gas chromatography. Approximately 126 research papers on the speciation and determination of mercury by various analytical techniques published in international journals since 2013 are reviewed. PMID:26236539

  14. Analytical Electrochemistry: Theory and Instrumentation of Dynamic Techniques.

    ERIC Educational Resources Information Center

    Johnson, Dennis C.

    1980-01-01

    Emphasizes trends in the development of six topics concerning analytical electrochemistry, including books and reviews (34 references cited), mass transfer (59), charge transfer (25), surface effects (33), homogeneous reactions (21), and instrumentation (31). (CS)

  15. Analytical Electrochemistry: Theory and Instrumentation of Dynamic Techniques.

    ERIC Educational Resources Information Center

    Johnson, Dennis C.

    1980-01-01

    Emphasizes trends in the development of six topics concerning analytical electrochemistry, including books and reviews (34 references cited), mass transfer (59), charge transfer (25), surface effects (33), homogeneous reactions (21), and instrumentation (31). (CS)

  16. An Analytic Technique for Investigating Mode-Locked Lasers

    SciTech Connect

    Usechak, N.G.; Agrawal, G.P.

    2005-09-30

    We present an analytic theory capable of predicting pulse parameters in mode-locked lasers in the presence of dispersion and nonlinearity. Excellent agreement is obtained between this approach and full numerical solutions.

  17. Social Data Analytics Using Tensors and Sparse Techniques

    ERIC Educational Resources Information Center

    Zhang, Miao

    2014-01-01

    The development of internet and mobile technologies is driving an earthshaking social media revolution. They bring the internet world a huge amount of social media content, such as images, videos, comments, etc. Those massive media content and complicate social structures require the analytic expertise to transform those flood of information into…

  18. Microorganisms as Analytical Indicators. Experimental Methods and Techniques,

    DTIC Science & Technology

    1980-01-01

    analytic indicators: gram- negative and gram-positive sporiferous and nonsporiferous bacteria, yeasts, mycelial fungi, and actinomycetes (Refs. 4, 6-8...growing species of microorganisms, the cultivation period is appropriately increased. This factor is less important for actinomycetes , fungi and sporiferous

  19. Challenges of Using Learning Analytics Techniques to Support Mobile Learning

    ERIC Educational Resources Information Center

    Arrigo, Marco; Fulantelli, Giovanni; Taibi, Davide

    2015-01-01

    Evaluation of Mobile Learning remains an open research issue, especially as regards the activities that take place outside the classroom. In this context, Learning Analytics can provide answers, and offer the appropriate tools to enhance Mobile Learning experiences. In this poster we introduce a task-interaction framework, using learning analytics…

  20. Analytical balance-based Faraday magnetometer

    NASA Astrophysics Data System (ADS)

    Riminucci, Alberto; Uhlarz, Marc; De Santis, Roberto; Herrmannsdörfer, Thomas

    2017-03-01

    We introduce a Faraday magnetometer based on an analytical balance in which we were able to apply magnetic fields up to 0.14 T. We calibrated it with a 1 mm Ni sphere previously characterized in a superconducting quantum interference device (SQUID) magnetometer. The proposed magnetometer reached a theoretical sensitivity of 3 × 10-8 A m2. We demonstrated its operation on magnetic composite scaffolds made of poly(ɛ-caprolactone)/iron-doped hydroxyapatite. To confirm the validity of the method, we measured the same scaffold properties in a SQUID magnetometer. The agreement between the two measurements was within 5% at 0.127 T and 12% at 24 mT. With the addition, for a small cost, of a permanent magnet and computer controlled linear translators, we were thus able to assemble a Faraday magnetometer based on an analytical balance, which is a virtually ubiquitous instrument. This will make simple but effective magnetometry easily accessible to most laboratories, in particular, to life sciences ones, which are increasingly interested in magnetic materials.

  1. Comparison of a two-dimensional adaptive-wall technique with analytical wall interference correction techniques

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.

    1992-01-01

    A two dimensional airfoil model was tested in the adaptive wall test section of the NASA Langley 0.3 meter Transonic Cryogenic Tunnel (TCT) and in the ventilated test section of the National Aeronautical Establishment Two Dimensional High Reynold Number Facility (HRNF). The primary goal of the tests was to compare different techniques (adaptive test section walls and classical, analytical corrections) to account for wall interference. Tests were conducted over a Mach number range from 0.3 to 0.8 at chord Reynolds numbers of 10 x 10(exp 6), 15 x 10(exp 6), and 20 x 10(exp 6). The angle of attack was varied from about 12 degrees up to stall. Movement of the top and bottom test section walls was used to account for the wall interference in the HRNF tests. The test results are in good agreement.

  2. Synchrotron X-ray Analytical Techniques for Studying Materials Electrochemistry in Rechargeable Batteries

    DOE PAGES

    Lin, Feng; Liu, Yijin; Yu, Xiqian; ...

    2017-08-30

    Rechargeable battery technologies have ignited major breakthroughs in contemporary society, including but not limited to revolutions in transportation, electronics, and grid energy storage. The remarkable development of rechargeable batteries is largely attributed to in-depth efforts to improve battery electrode and electrolyte materials. There are, however, still intimidating challenges of lower cost, longer cycle and calendar life, higher energy density, and better safety for large scale energy storage and vehicular applications. Further progress with rechargeable batteries may require new chemistries (lithium ion batteries and beyond) and better understanding of materials electrochemistry in the various battery technologies. In the past decade, advancementmore » of battery materials has been complemented by new analytical techniques that are capable of probing battery chemistries at various length and time scales. Synchrotron X-ray techniques stand out as one of the most effective methods that allows for nearly nondestructive probing of materials characteristics such as electronic and geometric structures with various depth sensitivities through spectroscopy, scattering, and imaging capabilities. This article begins with the discussion of various rechargeable batteries and associated important scientific questions in the field, followed by a review of synchrotron X-ray based analytical tools (scattering, spectroscopy and imaging) and their successful applications (ex situ, in situ, and in operando) in gaining fundamental insights into these scientific questions. Furthermore, electron microscopy and spectroscopy complement the detection length scales of synchrotron X-ray tools, and are also discussed towards the end. We highlight the importance of studying battery materials by combining analytical techniques with complementary length sensitivities, such as the combination of X-ray absorption spectroscopy and electron spectroscopy with spatial resolution

  3. Paper-based analytical devices for environmental analysis.

    PubMed

    Meredith, Nathan A; Quinn, Casey; Cate, David M; Reilly, Thomas H; Volckens, John; Henry, Charles S

    2016-03-21

    The field of paper-based microfluidics has experienced rapid growth over the past decade. Microfluidic paper-based analytical devices (μPADs), originally developed for point-of-care medical diagnostics in resource-limited settings, are now being applied in new areas, such as environmental analyses. Low-cost paper sensors show great promise for on-site environmental analysis; the theme of ongoing research complements existing instrumental techniques by providing high spatial and temporal resolution for environmental monitoring. This review highlights recent applications of μPADs for environmental analysis along with technical advances that may enable μPADs to be more widely implemented in field testing.

  4. Analytic Syntax: A Technique for Advanced Level Reading

    ERIC Educational Resources Information Center

    Berman, Ruth

    1975-01-01

    The technique explained here can increase a foreign student's awareness of English grammatical and rhetorical structures. Structural paraphrase is a syntactic reformulation of difficult phrases with minimal vocabulary changes. The technique is illustrated and suggestions are given for class presentation. (CHK)

  5. Analysis of Volatile Compounds by Advanced Analytical Techniques and Multivariate Chemometrics.

    PubMed

    Lubes, Giuseppe; Goodarzi, Mohammad

    2017-05-10

    Smelling is one of the five senses, which plays an important role in our everyday lives. Volatile compounds are, for example, characteristics of food where some of them can be perceivable by humans because of their aroma. They have a great influence on the decision making of consumers when they choose to use a product or not. In the case where a product has an offensive and strong aroma, many consumers might not appreciate it. On the contrary, soft and fresh natural aromas definitely increase the acceptance of a given product. These properties can drastically influence the economy; thus, it has been of great importance to manufacturers that the aroma of their food product is characterized by analytical means to provide a basis for further optimization processes. A lot of research has been devoted to this domain in order to link the quality of, e.g., a food to its aroma. By knowing the aromatic profile of a food, one can understand the nature of a given product leading to developing new products, which are more acceptable by consumers. There are two ways to analyze volatiles: one is to use human senses and/or sensory instruments, and the other is based on advanced analytical techniques. This work focuses on the latter. Although requirements are simple, low-cost technology is an attractive research target in this domain; most of the data are generated with very high-resolution analytical instruments. Such data gathered based on different analytical instruments normally have broad, overlapping sensitivity profiles and require substantial data analysis. In this review, we have addressed not only the question of the application of chemometrics for aroma analysis but also of the use of different analytical instruments in this field, highlighting the research needed for future focus.

  6. High-performance thin layer chromatography: A powerful analytical technique in pharmaceutical drug discovery

    PubMed Central

    Attimarad, Mahesh; Ahmed, K. K. Mueen; Aldhubaib, Bandar E.; Harsha, Sree

    2011-01-01

    Analysis of pharmaceutical and natural compounds and newer drugs is commonly used in all the stages of drug discovery and development process. High-performance thin layer chromatography is one of the sophisticated instrumental techniques based on the full capabilities of thin layer chromatography. The advantages of automation, scanning, full optimization, selective detection principle, minimum sample preparation, hyphenation, and so on enable it to be a powerful analytical tool for chromatographic information of complex mixtures of pharmaceuticals, natural products, clinical samples, food stuffs, and so on. PMID:23781433

  7. Text-Displaying Colorimetric Paper-Based Analytical Device.

    PubMed

    Yamada, Kentaro; Suzuki, Koji; Citterio, Daniel

    2017-08-25

    This paper describes a paper-based analytical device allowing the direct semiquantitative interpretation of the result of a chemical assay in the form of "text". The combined use of a classical colorimetric indicator system and an additional inert colorant enables a versatile text-displaying detection mechanism on a paper device. For proof-of-concept, urinary protein has been selected as a model analytical target. The whole text-displaying paper device has been developed based on printing techniques including wax printing, inkjet printing, and 3D printing. The results of user tests performed with protein (human serum albumin) samples in aqueous standard solutions and human urine demonstrated that the accuracy was comparable for the elaborated paper device (74.7% for standard samples and 66.7% for urine) and a conventional colorimetric urine dipstick (67.2% for standard samples and 65.3% for urine). Storage stability as long as at least 117 days has been confirmed based on software-assisted quantitative color analysis. The developed text-displaying approach is proposed as an alternative simple detection motif for paper-based analytical devices.

  8. Highly time-resolved evaluation technique of instantaneous amplitude and phase difference using analytic signals for multi-channel diagnostics

    SciTech Connect

    Ohshima, S. Kobayashi, S.; Yamamoto, S.; Nagasaki, K.; Mizuuchi, T.; Kado, S.; Okada, H.; Minami, T.; Shi, N.; Konoshima, S.; Sano, F.; Lee, H. Y.; Zang, L.; Kenmochi, N.; Kasajima, K.; Ohtani, Y.; Nagae, Y.

    2014-11-15

    A fluctuation analysis technique using analytic signals is proposed. Analytic signals are suitable to characterize a single mode with time-dependent amplitude and frequency, such as an MHD mode observed in fusion plasmas since the technique can evaluate amplitude and frequency at a specific moment without limitations of temporal and frequency resolutions, which is problematic in Fourier-based analyses. Moreover, a concept of instantaneous phase difference is newly introduced, and error of the evaluated phase difference and its error reduction techniques using conditional/ensemble averaging are discussed. These techniques are applied to experimental data of the beam emission spectroscopic measurement in the Heliotron J device, which demonstrates that the technique can describe nonlinear evolution of MHD instabilities. This technique is widely applicable to other diagnostics having necessity to evaluate phase difference.

  9. Analytical techniques and method validation for the measurement of selected semivolatile and nonvolatile organofluorochemicals in air.

    PubMed

    Reagen, William K; Lindstrom, Kent R; Thompson, Kathy L; Flaherty, John M

    2004-09-01

    The widespread use of semi- and nonvolatile organofluorochemicals in industrial facilities, concern about their persistence, and relatively recent advancements in liquid chromatography/mass spectrometry (LC/MS) technology have led to the development of new analytical methods to assess potential worker exposure to airborne organofluorochemicals. Techniques were evaluated for the determination of 19 organofluorochemicals and for total fluorine in ambient air samples. Due to the potential biphasic nature of most of these fluorochemicals when airborne, Occupational Safety and Health Administration (OSHA) versatile sampler (OVS) tubes were used to simultaneously trap fluorochemical particulates and vapors from workplace air. Analytical methods were developed for OVS air samples to quantitatively analyze for total fluorine using oxygen bomb combustion/ion selective electrode and for 17 organofluorochemicals using LC/MS and gas chromatography/mass spectrometry (GC/MS). The experimental design for this validation was based on the National Institute of Occupational Safety and Health (NIOSH) Guidelines for Air Sampling and Analytical Method Development and Evaluation, with some revisions of the experimental design. The study design incorporated experiments to determine analytical recovery and stability, sampler capacity, the effect of some environmental parameters on recoveries, storage stability, limits of detection, precision, and accuracy. Fluorochemical mixtures were spiked onto each OVS tube over a range of 0.06-6 microg for each of 12 compounds analyzed by LC/MS and 0.3-30 microg for 5 compounds analyzed by GC/MS. These ranges allowed reliable quantitation at 0.001-0.1 mg/m3 in general for LC/MS analytes and 0.005-0.5 mg/m3 for GC/MS analytes when 60 L of air are sampled. The organofluorochemical exposure guideline (EG) is currently 0.1 mg/m3 for many analytes, with one exception being ammonium perfluorooctanoate (EG is 0.01 mg/m3). Total fluorine results may be used

  10. Nuclear analytical techniques with neutron beams at the Univ. of Texas at Austin

    SciTech Connect

    Uenlue, K.; Wehring, B.W.

    1996-12-31

    Neutron beams produced by nuclear research reactors can be used for analytical chemical analysis by measuring nuclear radiation produced by neutron capture. Prompt gamma activation analysis (PGAA) and neutron depth profiling (NDP) are two such analytical techniques. For the last three decades, these techniques have been applied at a number of research reactors around the world. Within the last 4 yr, we have developed NDP and PGAA facilities at The University of Texas at Austin research reactor, a 1-MW TRIGA Mark II reactor. Brief descriptions of the facilities and summaries of activities for these analytical techniques at the University of Texas at Austin are provided in this paper.

  11. Analytical Solution of the Two-Frequency Lidar Inversion Technique

    NASA Astrophysics Data System (ADS)

    Ackermann, Jrg

    1999-12-01

    A two-frequency lidar inversion on the assumptions of a range-independent relationship between the extinction coefficients of the two considered lidar wavelengths and of constant extinction-to-backscatter ratios was originally developed by Potter Appl. Opt. 26, 1250 (1987) . It is an iterative procedure to retrieve the boundary value for solution of the single-scatter lidar equation. This boundary value is expressed by the aerosol transmission along the evaluated lidar path. Recently, Kunz Appl. Opt. 38, 1015 (1999) stated that there is not enough information in the lidar signals of two wavelengths to obtain a unique solution for the boundary value and hence for the aerosol extinction profile. It is shown that a unique solution of the two-frequency lidar inversion exists, for which an analytical expression of the boundary value and, hence, the aerosol extinction profile, is given.

  12. Monitoring of the drinking Water using of alternative Analytical Techniques

    NASA Astrophysics Data System (ADS)

    Cimpoca, Gh. V.; Radulescu, C.; Popescu, I. V.; Dulama, I. D.; Bancuta, I.; Gheboianu, A. I.; Cimpoca, M.; Cernica, I.; Staicu, L.

    2010-01-01

    In this paper we study and monitoring the drinking waters with Quartz Crystal Microbalance (QCM) versus Atomic Absorption Spectrometry (AAS) and classical analytical methods (pH, conductivity/resistivity, TDS, salinity). Our studies present a new application of quartz crystal microbalance (QCM) for measure and identify trace quantities of metals and volatile organic compounds (VOC) in water. QCM was adapted for many different uses by developing electrodes that respond to different target molecules. For our experiences we use quartz crystal sensor with 1.25 cm2 sensitive area at 5 MHz resonance frequency and CrAu electrode (20 nm Cr and 200 nm Au).We monitoring in real time the quality of water by controlling the inorganic and organic impurities. We evaluate the utility of QCM sensors to detect a range of VOC contaminant which is complementary with AAS. Some polar VOC contaminants were tested: acetone, isopropanol and ethylene glycol.

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

    PubMed

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

    2017-03-01

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

  14. Analytic mind use and interpsychic communication: driving force in analytic technique, pathway to unconscious mental life.

    PubMed

    Diamond, Michael J

    2014-07-01

    Developed from established psychoanalytic knowledge among different psychoanalytic cultures concerning unconscious interpsychic communication, analysts' use of their receptive mental experience--their analytic mind use, including the somatic, unconscious, and less accessible derivatives--represents a significant investigative road to patients' unconscious mental life, particularly with poorly symbolized mental states. The author expands upon this tradition, exploring what happens when patients unconsciously experience and identify with the analyst's psychic functioning. The technical implications of the analyst's "instrument" are described, including the analyst's ego regression, creation of inner space, taking mind as object, bearing uncertainty and intense affect, and self-analysis. Brief case vignettes illustrate the structure and obstacles to this work.

  15. Long-term density evolution through semi-analytical and differential algebra techniques

    NASA Astrophysics Data System (ADS)

    Wittig, Alexander; Colombo, Camilla; Armellin, Roberto

    2017-08-01

    This paper introduces and combines for the first time two techniques to allow long-term density propagation in astrodynamics. First, we introduce an efficient method for the propagation of phase space densities based on differential algebra (DA) techniques. Second, this DA density propagator is used in combination with a DA implementation of the averaged orbital dynamics through semi-analytical methods. This approach combines the power of orbit averaging with the efficiency of DA techniques. While the DA-based method for the propagation of densities introduced in this paper is independent of the dynamical system under consideration, the particular combination of DA techniques with averaged equations of motion yields a fast and accurate technique to propagate large clouds of initial conditions and their associated probability density functions very efficiently for long time. This enables the study of the long-term behavior of particles subjected to the given dynamics. To demonstrate the effectiveness of the proposed approach, the evolution of a cloud of high area-to-mass objects in Medium Earth Orbit is reproduced considering the effects of solar radiation pressure, the Earth's oblateness and luni-solar perturbations. The method can propagate 10,000 random fragments and their density for 1 year within a few seconds on a common desktop PC.

  16. Long-term density evolution through semi-analytical and differential algebra techniques

    NASA Astrophysics Data System (ADS)

    Wittig, Alexander; Colombo, Camilla; Armellin, Roberto

    2017-02-01

    This paper introduces and combines for the first time two techniques to allow long-term density propagation in astrodynamics. First, we introduce an efficient method for the propagation of phase space densities based on differential algebra (DA) techniques. Second, this DA density propagator is used in combination with a DA implementation of the averaged orbital dynamics through semi-analytical methods. This approach combines the power of orbit averaging with the efficiency of DA techniques. While the DA-based method for the propagation of densities introduced in this paper is independent of the dynamical system under consideration, the particular combination of DA techniques with averaged equations of motion yields a fast and accurate technique to propagate large clouds of initial conditions and their associated probability density functions very efficiently for long time. This enables the study of the long-term behavior of particles subjected to the given dynamics. To demonstrate the effectiveness of the proposed approach, the evolution of a cloud of high area-to-mass objects in Medium Earth Orbit is reproduced considering the effects of solar radiation pressure, the Earth's oblateness and luni-solar perturbations. The method can propagate 10,000 random fragments and their density for 1 year within a few seconds on a common desktop PC.

  17. Methods and Techniques for Clinical Text Modeling and Analytics

    ERIC Educational Resources Information Center

    Ling, Yuan

    2017-01-01

    This study focuses on developing and applying methods/techniques in different aspects of the system for clinical text understanding, at both corpus and document level. We deal with two major research questions: First, we explore the question of "How to model the underlying relationships from clinical notes at corpus level?" Documents…

  18. Visual Analytics for Law Enforcement: Deploying a Service-Oriented Analytic Framework for Web-based Visualization

    SciTech Connect

    Dowson, Scott T.; Bruce, Joseph R.; Best, Daniel M.; Riensche, Roderick M.; Franklin, Lyndsey; Pike, William A.

    2009-04-14

    This paper presents key components of the Law Enforcement Information Framework (LEIF) that provides communications, situational awareness, and visual analytics tools in a service-oriented architecture supporting web-based desktop and handheld device users. LEIF simplifies interfaces and visualizations of well-established visual analytical techniques to improve usability. Advanced analytics capability is maintained by enhancing the underlying processing to support the new interface. LEIF development is driven by real-world user feedback gathered through deployments at three operational law enforcement organizations in the US. LEIF incorporates a robust information ingest pipeline supporting a wide variety of information formats. LEIF also insulates interface and analytical components from information sources making it easier to adapt the framework for many different data repositories.

  19. Electrical field-induced extraction and separation techniques: promising trends in analytical chemistry--a review.

    PubMed

    Yamini, Yadollah; Seidi, Shahram; Rezazadeh, Maryam

    2014-03-03

    Sample preparation is an important issue in analytical chemistry, and is often a bottleneck in chemical analysis. So, the major incentive for the recent research has been to attain faster, simpler, less expensive, and more environmentally friendly sample preparation methods. The use of auxiliary energies, such as heat, ultrasound, and microwave, is one of the strategies that have been employed in sample preparation to reach the above purposes. Application of electrical driving force is the current state-of-the-art, which presents new possibilities for simplifying and shortening the sample preparation process as well as enhancing its selectivity. The electrical driving force has scarcely been utilized in comparison with other auxiliary energies. In this review, the different roles of electrical driving force (as a powerful auxiliary energy) in various extraction techniques, including liquid-, solid-, and membrane-based methods, have been taken into consideration. Also, the references have been made available, relevant to the developments in separation techniques and Lab-on-a-Chip (LOC) systems. All aspects of electrical driving force in extraction and separation methods are too specific to be treated in this contribution. However, the main aim of this review is to provide a brief knowledge about the different fields of analytical chemistry, with an emphasis on the latest efforts put into the electrically assisted membrane-based sample preparation systems. The advantages and disadvantages of these approaches as well as the new achievements in these areas have been discussed, which might be helpful for further progress in the future.

  20. Facilitating the analysis of immunological data with visual analytic techniques.

    PubMed

    Shih, David C; Ho, Kevin C; Melnick, Kyle M; Rensink, Ronald A; Kollmann, Tobias R; Fortuno, Edgardo S

    2011-01-02

    Visual analytics (VA) has emerged as a new way to analyze large dataset through interactive visual display. We demonstrated the utility and the flexibility of a VA approach in the analysis of biological datasets. Examples of these datasets in immunology include flow cytometry, Luminex data, and genotyping (e.g., single nucleotide polymorphism) data. Contrary to the traditional information visualization approach, VA restores the analysis power in the hands of analyst by allowing the analyst to engage in real-time data exploration process. We selected the VA software called Tableau after evaluating several VA tools. Two types of analysis tasks analysis within and between datasets were demonstrated in the video presentation using an approach called paired analysis. Paired analysis, as defined in VA, is an analysis approach in which a VA tool expert works side-by-side with a domain expert during the analysis. The domain expert is the one who understands the significance of the data, and asks the questions that the collected data might address. The tool expert then creates visualizations to help find patterns in the data that might answer these questions. The short lag-time between the hypothesis generation and the rapid visual display of the data is the main advantage of a VA approach.

  1. Visual analytics techniques for large multi-attribute time series data

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Dayal, Umeshwar; Keim, Daniel A.

    2008-01-01

    Time series data commonly occur when variables are monitored over time. Many real-world applications involve the comparison of long time series across multiple variables (multi-attributes). Often business people want to compare this year's monthly sales with last year's sales to make decisions. Data warehouse administrators (DBAs) want to know their daily data loading job performance. DBAs need to detect the outliers early enough to act upon them. In this paper, two new visual analytic techniques are introduced: The color cell-based Visual Time Series Line Charts and Maps highlight significant changes over time in a long time series data and the new Visual Content Query facilitates finding the contents and histories of interesting patterns and anomalies, which leads to root cause identification. We have applied both methods to two real-world applications to mine enterprise data warehouse and customer credit card fraud data to illustrate the wide applicability and usefulness of these techniques.

  2. Chemometric classification techniques as a tool for solving problems in analytical chemistry.

    PubMed

    Bevilacqua, Marta; Nescatelli, Riccardo; Bucci, Remo; Magrì, Andrea D; Magrì, Antonio L; Marini, Federico

    2014-01-01

    Supervised pattern recognition (classification) techniques, i.e., the family of chemometric methods whose aim is the prediction of a qualitative response on a set of samples, represent a very important assortment of tools for solving problems in several areas of applied analytical chemistry. This paper describes the theory behind the chemometric classification techniques most frequently used in analytical chemistry together with some examples of their application to real-world problems.

  3. New analytical techniques for mycotoxins in complex organic matrices

    SciTech Connect

    Bicking, M.K.L.

    1982-01-01

    Air samples are collected for analysis from the Ames Solid Waste Recovery System. The high level of airborne fungi within the processing area is of concern due to the possible presence of toxic mycotoxins, and carcinogenic fungal metabolites. An analytical method has been developed to determine the concentration of aflatoxins B1, B2, G1, and G2 in the air of the plant which produces Refuse Derived Fuel (RDF). After extraction with methanol, some components in the matrix are precipitated by dissolving the samples in 30% acetonitrile/chloroform. An aliquot of this solution is injected onto a Styragel column where the sample components undergo simultaneous size exclusion and reverse phase partitioning. The Styragel column appears to have a useable lifetime of more than six months. After elution from Styragel, the sample is diverted to a second column containing Florisil which has been modified with oxalic acid and deactivated with water. Aflatoxins are eluted with 5% water/acetone. After removal of this solvent, the sample is dissolved in 150 ..mu..L of a spotting solvent and the entire sample applied to a thin layer chromatography (TLC) plate using a unique sample applicator developed here. The aflatoxins on the TLC plate are analyzed by laser fluorescence. A detection limit of 10 pg is possible for aflatoxin standards using a nitrogen laser as the excitation source. Sample concentrations are determined by comparing with an internal standard, a specially synthesized aflatoxin derivative. In two separate RDF samples, aflatoxin B1 was found at levels of 6.5 and 17.0 ppB. In a separate study, the spore pigment in Aspergillus flavus was isolated. The mass spectrum indicates a molecular weight in excess of 700. Only aliphatic hydrocarbons have been identified in the mass spectrum of products from a permanganate oxidation.

  4. New analytical techniques to facilitate preformulation screening in propellant systems.

    PubMed

    Mogalian, Erik; Kuehl, Philip J; Myrdal, Paul B

    2007-08-01

    The objective of these studies was to investigate the applicability of an online direct inject HPLC method for the preformulation screening of pharmaceutical agents in pressurized metered dose inhalers (MDIs). The technique was initially utilized for the solubility determination of solid solutes. This study explores the extension of the online direct inject method for the evaluation of drug stability in propellant systems as well as for the analysis of MDI vials crimped with metered valves. Through-life content analysis confirmed that a single vial may be repeatedly sampled, thus facilitating the stability evaluation of a single unit over time. The method was successfully used for evaluating the stability of a model drug, as a function of several different formulation configurations, with minimal sample numbers. Additionally, studies determined that after modifications were made to the injection coupler, the technique was also feasible for use with 50 and 100 microL metered valves, however further modifications are necessary for 25 microL valves.

  5. Analytic and interferometric techniques for the Laser Interferometer Space Antenna

    NASA Astrophysics Data System (ADS)

    Pollack, Scott E.

    The Laser Interferometer Space Antenna (LISA) is being designed to detect and study in detail gravitational waves from sources throughout the Universe such as massive black holes. The conceptual formulation of the LISA space-borne gravitational wave detector is now well developed. The interferometric measurements between the sciencecraft remain one of the most important technological and scientific design areas for the mission. Our work has concentrated on developing the interferometric technologies to create a LISA-like optical signal and to measure the phase of that signal using commercially available instruments. One of the most important goals of this research is to demonstrate the LISA phase timing and phase reconstruction for a LISA-like fringe signal, in the case of a high fringe rate and a low signal level. To this end we have constructed a table-top interferometer which produces LISA-like fringe signals. Over the past few years questions have been raised concerning the use of laser communications links between sciencecraft to transmit phase information crucial to the reduction of laser frequency noise in the LISA science measurement. The concern is that applying medium frequency phase modulations to the laser carrier could compromise the phase stability of the LISA fringe signal. We have modified our table-top interferometer by applying a phase modulation to the laser beam in order to evaluate the effects of such modulations on the LISA science fringe signal. We have demonstrated that the phase resolution of the science signal is not degraded by the presence of medium frequency phase modulations. Each spacecraft in LISA houses a proof mass which follows a geodesic through space. Disturbances that change the proof mass position, momentum, and acceleration will appear in the LISA data stream as additive quadratic functions. These data disturbances inhibit signal extraction and must be removed. Much of our analytical work has been focused on discussing the

  6. Effect of analytical techniques on measured ambient NO2 concentrations.

    PubMed

    Goyal, S K; Gavane, A G

    2005-06-01

    A study was carried out with specific reference to NO2 measurements in three countries (designated as A, B and C), which use three different manual methods; viz. Sodium Arsenite, Greiss Saltzman and TGS-ANSA for the determination of NO2 in ambient air. Significant deviation (up to 36 + %) was observed in measured NO, ion concentration when spiked samples were analyzed using these methods. Further, to make the data inter-comparable, exhaustive laboratory studies were carried out on these manual methods. Different concentration levels of NO2 were generated in the laboratory and analyzed by these methods simultaneously. The results were evaluated statistically. An interrelationship among the methods was established as method conversion factors (MCF). This would be useful in relating atmospheric concentration of NO2 among various countries, where different measurement techniques are adopted.

  7. Fabrication and Operation of Paper-Based Analytical Devices.

    PubMed

    Jiang, Xiao; Fan, Z Hugh

    2016-06-12

    This review focuses on the fabrication techniques and operational components of microfluidic paper-based analytical devices (μPADs). Being low-cost, user-friendly, fast, and simple, μPADs have seen explosive growth in the literature in the last decade. Many different materials and technologies have been employed to fabricate μPADs for various applications, including those that employ patterning, the creation of physical boundaries, and three-dimensional structures. In addition to fabrication techniques, flow control and other operational components in μPADs are of great interest. These components enable μPADs to control flow rates, direct flow paths via valves, sequentially deliver reagents automatically, and display test results, all of which will make μPADs more suitable for point-of-care applications.

  8. Analytical model for Transient Current Technique (TCT) signal prediction and analysis for thin interface characterization

    NASA Astrophysics Data System (ADS)

    Bronuzzi, J.; Mapelli, A.; Sallese, J. M.

    2016-12-01

    A silicon wafer bonding technique has been recently proposed for the fabrication of monolithic silicon radiation detectors. This new process would enable direct bonding of a read-out electronic chip wafer on a highly resistive silicon substrate wafer. Therefore, monolithic silicon detectors could be fabricated in this way which would allow the free choice of electronic chips and high resistive silicon bulk, even from different providers. Moreover, a monolithic detector with a high resistive bulk would also be available. Electrical properties of the bonded interface are then critical for this application. Indeed, mobile charges generated by radiation inside the bonded bulk are expected to transit through the interface to be collected by the read-out electronics. In order to characterize this interface, the concept of Transient Current Technique (TCT) has been explored by means of numerical simulations combined with a physics based analytical model. In this work, the analytical model giving insight into the physics behind the TCT dependence upon interface traps is validated using both TCAD simulations and experimental measurements.

  9. Integrating Organic Matter Structure with Ecosystem Function using Advanced Analytical Chemistry Techniques

    NASA Astrophysics Data System (ADS)

    Boot, C. M.

    2012-12-01

    Microorganisms are the primary transformers of organic matter in terrestrial and aquatic ecosystems. The structure of organic matter controls its bioavailability and researchers have long sought to link the chemical characteristics of the organic matter pool to its lability. To date this effort has been primarily attempted using low resolution descriptive characteristics (e.g. organic matter content, carbon to nitrogen ratio, aromaticity, etc .). However, recent progress in linking these two important ecosystem components has been advanced using advanced high resolution tools (e.g. nuclear magnetic resonance (NMR) spectroscopy, and mass spectroscopy (MS)-based techniques). A series of experiments will be presented that highlight the application of high resolution techniques in a variety of terrestrial and aquatic ecosystems with the focus on how these data explicitly provide the foundation for integrating organic matter structure into our concept of ecosystem function. The talk will highlight results from a series of experiments including: an MS-based metabolomics and fluorescence excitation emission matrix approach evaluating seasonal and vegetation based changes in dissolved organic matter (DOM) composition from arctic soils; Fourier transform ion cyclotron resonance (FTICR) MS and MS metabolomics analysis of DOM from three lakes in an alpine watershed; and the transformation of 13C labeled glucose track with NMR during a rewetting experiment from Colorado grassland soils. These data will be synthesized to illustrate how the application of advanced analytical techniques provides novel insight into our understanding of organic matter processing in a wide range of ecosystems.

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

    PubMed

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

    2015-12-01

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

  11. Analytical Bibliography for Water Supply and Conservation Techniques.

    DTIC Science & Technology

    1982-01-01

    variable percentage plan PERSONAL CONTACT per capita use speaker program prior use bases slide show Determination of priority uses booths at fairs...utility revenues may be useful in determining effectiveness of such a measure. 186 Marshall, Hubert . 1966. Politics and Efficiency in Water Development...Feineussen; (4) "Water Reuse in Industry," by L. K. Cecil ; (5) "Reuse of Water for Municipal Purposes," by G. J. Stander; (6) "Pressure-Driven

  12. Detection of irradiated chestnuts: preliminary study using three analytical techniques

    NASA Astrophysics Data System (ADS)

    Mangiacotti, Michele; Chiaravalle, Antonio Eugenio; Marchesani, Giuliana; De Sio, Antonio; Boniglia, Concetta; Bortolin, Emanuela; Onori, Sandro

    2009-07-01

    Irradiation of chestnuts has recently been considered as an alternative treatment to fumigation to reduce the considerable amount of the product normally lost during post-harvest period. The treatment is allowed in countries such as Korea and, in view of a possible extension to European countries, to permit the legal controls as required by the directive 1999/2/EC [ European Parliament and Council Directive, 1999/2/EC, on the approximation of the laws of the Member States concerning foods and food ingredients treated with ionising radiation. Official Journal of the European Communities. L 66/16 of 13.3.1999] and meet consumer consensus, reliable methods for detecting irradiated chestnuts have to be proposed. The aim of the present work was to test the efficacy of the European Standard EN 13751, EN 1788, EN 1787 and EN 13708 in detecting irradiated chestnuts. For this purpose, six sets of "Montella" chestnuts, a typical Italian variety recognized as a PGI (protected geographical indication), non-irradiated and irradiated at different doses in the 0.1-1 kGy range, were analysed by thermoluminescence (TL), photo-stimulated luminescence (PSL) (screening and calibrated PSL) and ESR techniques. PSL and TL analysis results revealed the low luminescence sensitivity of the chestnuts. Nevertheless, PSL screening data were in the intermediate band above the negative threshold (at all doses except at the lowest one) and TL analysis led to correct positive classifications even at the lowest dose tested (0.15 Gy). On the contrary, no radio-induced ESR signal could be registered with the irradiated samples of chestnut shell or pulp.

  13. Classroom Writing Tasks and Students' Analytic Text-Based Writing

    ERIC Educational Resources Information Center

    Matsumura, Lindsay Clare; Correnti, Richard; Wang, Elaine

    2015-01-01

    The Common Core State Standards emphasize students writing analytically in response to texts. Questions remain about the nature of instruction that develops students' text-based writing skills. In the present study, we examined the role that writing task quality plays in students' mastery of analytic text-based writing. Text-based writing tasks…

  14. Cost and Schedule Analytical Techniques Development: Option 2 Year

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This Final Report summarizes the activities performed by Science Applications International Corporation (SAIC) for the Option 2 Year from December 1, 1996 through November 30, 1997. The Final Report is in compliance with Paragraph 5 of Section F of the contract. This CSATD contract provides products and deliverable in the form of models, data bases, methodologies, studies and analyses for the NASA Marshall Space Flight Center's (MSFC) Engineering Cost Office (PPO3) the Program Plans and Requirements Officer (PP02), and other user organizations. Detailed Monthly Progress reports were submitted to MSFC in accordance with the contract's Statement of Work, Section TV "Reporting and Documentation". These reports spelled out each month's specific work accomplishments, deliverables submitted, major meetings held, and other pertinent information. This Final Report will summarize these activities at higher level. During this contract Option Year, SAIC expended 29,830 man-hours in tile performance of tasks called out in the Statement of Work and reported oil in this yearly Final Report. This represents approximately 16 full-time EPs. Included are the basis Huntsville-based team, plus SAIC specialists in San Diego, Ames Research Center, Chicago, and Colorado Springs performing specific tasks for which they are uniquely qualified.

  15. A novel visualization technique for electric power grid analytics.

    PubMed

    Wong, Pak Chung; Schneider, Kevin; Mackey, Patrick; Foote, Harlan; Chin, George; Guttromson, Ross; Thomas, Jim

    2009-01-01

    The application of information visualization holds tremendous promise for the electric power industry, but its potential has so far not been sufficiently exploited by the visualization community. Prior work on visualizing electric power systems has been limited to depicting raw or processed information on top of a geographic layout. Little effort has been devoted to visualizing the physics of the power grids, which ultimately determines the condition and stability of the electricity infrastructure. Based on this assessment, we developed a novel visualization system prototype, GreenGrid, to explore the planning and monitoring of the North American Electricity Infrastructure. The paper discusses the rationale underlying the GreenGrid design, describes its implementation and performance details, and assesses its strengths and weaknesses against the current geographic-based power grid visualization. We also present a case study using GreenGrid to analyze the information collected moments before the last major electric blackout in the Western United States and Canada, and a usability study to evaluate the practical significance of our design in simulated real-life situations. Our result indicates that many of the disturbance characteristics can be readily identified with the proper form of visualization.

  16. Cost and Schedule Analytical Techniques Development: Option 1

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This Final Report summarizes the activities performed by Science Applications International Corporation (SAIC) for the base contract year from December 1, 1995 through November 30, 1996. The Final Report is in compliance with Paragraph 5 of Section F of the contract. This CSATD contract provides technical services and products to the NASA Marshall Space Flight Center's (MSFC) Engineering Cost Office (PPO3) and the Program Plans and Requirements Officer (PPO2). Detailed Monthly Progress Reports were submitted to MSFC in accordance with the contract's Statement of Work Section IV "Reporting and Documentation". These reports spelled out each month's specific work accomplishments, deliverables submitted, major meetings held, and other pertinent information. This Final Report will summarize these activities at a higher level.

  17. An Example of a Hakomi Technique Adapted for Functional Analytic Psychotherapy

    ERIC Educational Resources Information Center

    Collis, Peter

    2012-01-01

    Functional Analytic Psychotherapy (FAP) is a model of therapy that lends itself to integration with other therapy models. This paper aims to provide an example to assist others in assimilating techniques from other forms of therapy into FAP. A technique from the Hakomi Method is outlined and modified for FAP. As, on the whole, psychotherapy…

  18. Data analytic techniques for treatment outcome studies with pretest/posttest measurements: an extensive primer.

    PubMed

    Sheeber, L B; Sorensen, E D; Howe, S R

    1996-01-01

    This paper discusses several data analytic technique, for examining treatment efficacy in pretest-posttest control group designs. The following approaches are described: ANOVA on post scores, ANOVA on difference scores, split-plot repeated measures ANOVA, profile analysis, and ANOCOVA with prescore as the co-variate. Guidelines for choosing between available techniques are provided; the primary focus here is on the nature of the null hypothesis, the assumptions underlying the approach, and the power of the procedure. The importance of examining the characteristics of the data set in selecting an analytic technique is illustrated.

  19. Using morphometric and analytical techniques to characterize elephant ivory.

    PubMed

    Singh, Rina Rani; Goyal, Surendra Prakash; Khanna, Param Pal; Mukherjee, Pulok Kumar; Sukumar, Raman

    2006-10-16

    There is a need to characterize Asian elephant ivory and compare with African ivory for controlling illegal trade and implementation of national and international laws. In this paper, we characterize ivory of Asian and African elephants using Schreger angle measurements, elemental analysis {X-ray fluorescence (XRF), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and inductively coupled plasma-mass spectroscopy (ICP-MS)} and isotopic analysis. We recorded Schreger angle characteristics of elephant ivory at three different zones in ivory samples of African (n=12) and Asian (n=28) elephants. The Schreger angle ranged from 32 degrees to 145 degrees and 30 degrees to 153 degrees in Asian and African ivory, respectively. Elemental analysis (for Asian and African ivory) by XRF, ICP-AES and ICP-MS provided preliminary data. We attempted to ascertain source of origin of Asian elephant ivory similarly as in African ivory based on isotopes of carbon, nitrogen and strontium. We determined isotopic ratios of carbon (n=31) and nitrogen (n=31) corresponding to diet and rainfall, respectively. Reference ivory samples from five areas within India were analyzed using collagen and powder sample and the latter was found more suitable for forensic analysis. During our preliminary analysis, the range of delta13C values (-13.6+/-0.15 per thousand and -25.6+/-0.15 per thousand) and delta15N values (10.2+/-0.15 per thousand and 3.5+/-0.15 per thousand) were noted.

  20. Uncovering category specificity of genital sexual arousal in women: The critical role of analytic technique.

    PubMed

    Pulverman, Carey S; Hixon, J Gregory; Meston, Cindy M

    2015-10-01

    Based on analytic techniques that collapse data into a single average value, it has been reported that women lack category specificity and show genital sexual arousal to a large range of sexual stimuli including those that both match and do not match their self-reported sexual interests. These findings may be a methodological artifact of the way in which data are analyzed. This study examined whether using an analytic technique that models data over time would yield different results. Across two studies, heterosexual (N = 19) and lesbian (N = 14) women viewed erotic films featuring heterosexual, lesbian, and gay male couples, respectively, as their physiological sexual arousal was assessed with vaginal photoplethysmography. Data analysis with traditional methods comparing average genital arousal between films failed to detect specificity of genital arousal for either group. When data were analyzed with smoothing regression splines and a within-subjects approach, both heterosexual and lesbian women demonstrated different patterns of genital sexual arousal to the different types of erotic films, suggesting that sophisticated statistical techniques may be necessary to more fully understand women's genital sexual arousal response. Heterosexual women showed category-specific genital sexual arousal. Lesbian women showed higher arousal to the heterosexual film than the other films. However, within subjects, lesbian women showed significantly different arousal responses suggesting that lesbian women's genital arousal discriminates between different categories of stimuli at the individual level. Implications for the future use of vaginal photoplethysmography as a diagnostic tool of sexual preferences in clinical and forensic settings are discussed.

  1. Analytical techniques and computer algorithms combined for the rapid characterization of structural peptide and protein features.

    PubMed

    Caporale, C

    1998-11-01

    The most recent algorithms based on the use of modern analytical techniques for the assessment of structural peptide and protein features have been reviewed. No algorithm devoted to the realization of predictive models or statistical analysis has been discussed, but only methods furnishing information on the real structure of the molecules. In particular, the procedures designed for handling sequence and mass spectrometric data obtained from the analysis of unfractionated digestion mixtures allow the user to get rapid information on the structure of the target polypeptide. Two classes of methods are illustrated: the first regards the determination of the amino acid sequence, whereas the second used its knowledge to supply data on the localization, function and three-dimensional structure of disulphides.

  2. Adsorptive micro-extraction techniques--novel analytical tools for trace levels of polar solutes in aqueous media.

    PubMed

    Neng, N R; Silva, A R M; Nogueira, J M F

    2010-11-19

    A novel enrichment technique, adsorptive μ-extraction (AμE), is proposed for trace analysis of polar solutes in aqueous media. The preparation, stability tests and development of the analytical devices using two geometrical configurations, i.e. bar adsorptive μ-extraction (BAμE) and multi-spheres adsorptive μ-extraction (MSAμE) is fully discussed. From the several sorbent materials tested, activated carbons and polystyrene divinylbenzene phases demonstrated the best stability, robustness and to be the most suitable for analytical purposes. The application of both BAμE and MSAμE devices proved remarkable performance for the determination of trace levels of polar solutes and metabolites (e.g. pesticides, disinfection by-products, drugs of abuse and pharmaceuticals) in water matrices and biological fluids. By comparing AμE techniques with stir bar sorptive extraction based on polydimethylsiloxane phase, great effectiveness is attained overcoming the limitations of the latter enrichment approach regarding the more polar solutes. Furthermore, convenient sensitivity and selectivity is reached through AμE techniques, since the great advantage of this new analytical technology is the possibility to choose the most suitable sorbent to each particular type of application. The enrichment techniques proposed are cost-effective, easy to prepare and work-up, demonstrating robustness and to be a remarkable analytical tool for trace analysis of priority solutes in areas of recognized importance such as environment, forensic and other related life sciences.

  3. Analytical impact time and angle guidance via time-varying sliding mode technique.

    PubMed

    Zhao, Yao; Sheng, Yongzhi; Liu, Xiangdong

    2016-05-01

    To concretely provide a feasible solution for homing missiles with the precise impact time and angle, this paper develops a novel guidance law, based on the nonlinear engagement dynamics. The guidance law is firstly designed with the prior assumption of a stationary target, followed by the practical extension to a moving target scenario. The time-varying sliding mode (TVSM) technique is applied to fulfill the terminal constraints, in which a specific TVSM surface is constructed with two unknown coefficients. One is tuned to meet the impact time requirement and the other one is targeted with a global sliding mode, so that the impact angle constraint as well as the zero miss distance can be satisfied. Because the proposed law possesses three guidance gain as design parameters, the intercept trajectory can be shaped according to the operational conditions and missile׳s capability. To improve the tolerance of initial heading errors and broaden the application, a new frame of reference is also introduced. Furthermore, the analytical solutions of the flight trajectory, heading angle and acceleration command can be totally expressed for the prediction and offline parameter selection by solving a first-order linear differential equation. Numerical simulation results for various scenarios validate the effectiveness of the proposed guidance law and demonstrate the accuracy of the analytic solutions.

  4. Environmental vulnerability assessment using Grey Analytic Hierarchy Process based model

    SciTech Connect

    Sahoo, Satiprasad; Dhar, Anirban; Kar, Amlanjyoti

    2016-01-15

    Environmental management of an area describes a policy for its systematic and sustainable environmental protection. In the present study, regional environmental vulnerability assessment in Hirakud command area of Odisha, India is envisaged based on Grey Analytic Hierarchy Process method (Grey–AHP) using integrated remote sensing (RS) and geographic information system (GIS) techniques. Grey–AHP combines the advantages of classical analytic hierarchy process (AHP) and grey clustering method for accurate estimation of weight coefficients. It is a new method for environmental vulnerability assessment. Environmental vulnerability index (EVI) uses natural, environmental and human impact related factors, e.g., soil, geology, elevation, slope, rainfall, temperature, wind speed, normalized difference vegetation index, drainage density, crop intensity, agricultural DRASTIC value, population density and road density. EVI map has been classified into four environmental vulnerability zones (EVZs) namely: ‘low’, ‘moderate’ ‘high’, and ‘extreme’ encompassing 17.87%, 44.44%, 27.81% and 9.88% of the study area, respectively. EVI map indicates that the northern part of the study area is more vulnerable from an environmental point of view. EVI map shows close correlation with elevation. Effectiveness of the zone classification is evaluated by using grey clustering method. General effectiveness is in between “better” and “common classes”. This analysis demonstrates the potential applicability of the methodology. - Highlights: • Environmental vulnerability zone identification based on Grey Analytic Hierarchy Process (AHP) • The effectiveness evaluation by means of a grey clustering method with support from AHP • Use of grey approach eliminates the excessive dependency on the experience of experts.

  5. Analytical techniques for measuring the effects of acid deposition on coatings on wood

    SciTech Connect

    Balik, C.M.; Fornes, R.E.; Gilbert, R.D.

    1988-11-01

    Preliminary experiments were carried out to characterize the potential deleterious effects of acidic deposition on three representative paints: an oil alkyd paint and two acrylic latex formulations. The base-polymer latex common to both latex paints was also studied individually. Free films of paint were exposed to relatively high levels of gaseous SO2 and ultraviolet light, and were immersed in aqueous SO2 at pH 2.0. Several analytical techniques were used to assess the resulting chemical and physical changes in the paint films, including sorption and diffusion measurements, attenuated total-reflectance infrared spectroscopy, dynamic mechanical analysis, sol-gel analysis, contact-angle measurements, differential scanning calorimetry, and electron spin resonance. All techniques show promise for characterizing the early stages of damage to paint films caused by acidic deposition. The major effects noted include leaching of acid-soluble extender components upon immersion in aqueous SO2, and enhanced degradation of the base polymer upon exposure to gaseous SO2, and ultraviolet light.

  6. A review of analytical techniques for determination of oxicams, nimesulide and nabumetone.

    PubMed

    Starek, Małgorzata; Krzek, Jan

    2009-01-15

    Non-steroidal anti-inflammatory drugs (NSAIDs) are the group most often used in human health care, since they are available without prescription for treatment of fever and minor pain. The present review submitted the use of various analytical techniques for the determination of oxicams, nimesulide and nabumetone. This review covers the time period from 1990 to 2008 during which over 200 analytical methods including all types of chromatographic, spectrophotometric and voltammetric techniques were reported. Presented application concerns analysis of chosen NSAIDs from pharmaceutical formulations and biological samples.

  7. Simple, distance-based measurement for paper analytical devices.

    PubMed

    Cate, David M; Dungchai, Wijitar; Cunningham, Josephine C; Volckens, John; Henry, Charles S

    2013-06-21

    Paper-based analytical devices (PADs) represent a growing class of elegant, yet inexpensive chemical sensor technologies designed for point-of-use applications. Most PADs, however, still utilize some form of instrumentation such as a camera for quantitative detection. We describe here a simple technique to render PAD measurements more quantitative and straightforward using the distance of colour development as a detection motif. The so-called distance-based detection enables PAD chemistries that are more portable and less resource intensive compared to classical approaches that rely on the use of peripheral equipment for quantitative measurement. We demonstrate the utility and broad applicability of this technique with measurements of glucose, nickel, and glutathione using three different detection chemistries: enzymatic reactions, metal complexation, and nanoparticle aggregation, respectively. The results show excellent quantitative agreement with certified standards in complex sample matrices. This work provides the first demonstration of distance-based PAD detection with broad application as a class of new, inexpensive sensor technologies designed for point-of-use applications.

  8. Field analytical techniques for mercury in soils technology evaluation. Topical report, November 1994--March 1997

    SciTech Connect

    Solc, J.; Harju, J.A.; Grisanti, A.A.

    1998-02-01

    This report presents the evaluation of the four field analytical techniques for mercury detection in soils, namely (1) an anodic stripping voltametry technique (ASV) developed and tested by General Electric Corporation; (2) a static headspace analysis (SHSA) technique developed and tested by Dr. Ralph Turner of Oak Ridge National Laboratory; (3) the BiMelyze{reg_sign} Mercury Immunoassay (Bio) developed and tested by BioNebraska, Inc.; and (4) a transportable x-ray fluorescence (XRF) instrument/technique developed and tested by Spectrace, Inc.

  9. An analytic reconstruction method for PET based on cubic splines

    NASA Astrophysics Data System (ADS)

    Kastis, George A.; Kyriakopoulou, Dimitra; Fokas, Athanasios S.

    2014-03-01

    PET imaging is an important nuclear medicine modality that measures in vivo distribution of imaging agents labeled with positron-emitting radionuclides. Image reconstruction is an essential component in tomographic medical imaging. In this study, we present the mathematical formulation and an improved numerical implementation of an analytic, 2D, reconstruction method called SRT, Spline Reconstruction Technique. This technique is based on the numerical evaluation of the Hilbert transform of the sinogram via an approximation in terms of 'custom made' cubic splines. It also imposes sinogram thresholding which restricts reconstruction only within object pixels. Furthermore, by utilizing certain symmetries it achieves a reconstruction time similar to that of FBP. We have implemented SRT in the software library called STIR and have evaluated this method using simulated PET data. We present reconstructed images from several phantoms. Sinograms have been generated at various Poison noise levels and 20 realizations of noise have been created at each level. In addition to visual comparisons of the reconstructed images, the contrast has been determined as a function of noise level. Further analysis includes the creation of line profiles when necessary, to determine resolution. Numerical simulations suggest that the SRT algorithm produces fast and accurate reconstructions at realistic noise levels. The contrast is over 95% in all phantoms examined and is independent of noise level.

  10. [Evidence-based TEP technique].

    PubMed

    Köckerling, F

    2017-01-13

    The guidelines of all international hernia societies recommend as procedures of choice the laparoendoscopic techniques total extraperitoneal patch plasty (TEP) and transabdominal preperitoneal patch plasty (TAPP) as well as the open Lichtenstein operation for elective inguinal hernia repair. The learning curve associated with the laparoendoscopic techniques, in particular TEP, is longer than that for the open Lichtenstein technique due to the complexity of the procedures. Accordingly, for laparoendoscopic techniques it is particularly important that the operations are conducted in a standardized manner in compliance with the evidence-based recommendations given for the technical details. When procedures are carried out in strict compliance with the guidelines of the international hernia societies, low rates of perioperative complications, complication-related reoperations, recurrences and chronic pain can be expected for TEP. Compliance with the guidelines can also positively impact mastery of the learning curve for TEP. The technical guidelines on TEP are based on study results and on the experiences of numerous experts; therefore, it is imperative that they are implemented in routine surgical practice.

  11. A new multi-step technique with differential transform method for analytical solution of some nonlinear variable delay differential equations.

    PubMed

    Benhammouda, Brahim; Vazquez-Leal, Hector

    2016-01-01

    This work presents an analytical solution of some nonlinear delay differential equations (DDEs) with variable delays. Such DDEs are difficult to treat numerically and cannot be solved by existing general purpose codes. A new method of steps combined with the differential transform method (DTM) is proposed as a powerful tool to solve these DDEs. This method reduces the DDEs to ordinary differential equations that are then solved by the DTM. Furthermore, we show that the solutions can be improved by Laplace-Padé resummation method. Two examples are presented to show the efficiency of the proposed technique. The main advantage of this technique is that it possesses a simple procedure based on a few straight forward steps and can be combined with any analytical method, other than the DTM, like the homotopy perturbation method.

  12. The analytical investigations of ancient pottery from Kaveripakkam, Vellore dist, Tamilnadu by spectroscopic techniques.

    PubMed

    Ravisankar, R; Naseerutheen, A; Annamalai, G Raja; Chandrasekaran, A; Rajalakshmi, A; Kanagasabapathy, K V; Prasad, M V R; Satpathy, K K

    2014-01-01

    Analytical investigations using Fourier Transform infrared spectroscopy (FT-IR), Powder X-ray Diffraction (PXRD), Thermal Analysis (TG-DTA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) were carried out on ancient pottery fragments from Kaveripakkam, in order to outline manufacturing skills, technology information, firing condition and temperature of potteries. The whole set of data showed the firing temperature in the range of 800-900°C. The analytical characterization of the potsherds, by different complimentary techniques has allowed to identifying the raw materials and technology applied by the ancient artisans.

  13. The analytical investigations of ancient pottery from Kaveripakkam, Vellore dist, Tamilnadu by spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Ravisankar, R.; Naseerutheen, A.; Raja Annamalai, G.; Chandrasekaran, A.; Rajalakshmi, A.; Kanagasabapathy, K. V.; Prasad, M. V. R.; Satpathy, K. K.

    2014-03-01

    Analytical investigations using Fourier Transform infrared spectroscopy (FT-IR), Powder X-ray Diffraction (PXRD), Thermal Analysis (TG-DTA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) were carried out on ancient pottery fragments from Kaveripakkam, in order to outline manufacturing skills, technology information, firing condition and temperature of potteries. The whole set of data showed the firing temperature in the range of 800-900 °C. The analytical characterization of the potsherds, by different complimentary techniques has allowed to identifying the raw materials and technology applied by the ancient artisans.

  14. Evaluation of analytical performance based on partial order methodology.

    PubMed

    Carlsen, Lars; Bruggemann, Rainer; Kenessova, Olga; Erzhigitov, Erkin

    2015-01-01

    Classical measurements of performances are typically based on linear scales. However, in analytical chemistry a simple scale may be not sufficient to analyze the analytical performance appropriately. Here partial order methodology can be helpful. Within the context described here, partial order analysis can be seen as an ordinal analysis of data matrices, especially to simplify the relative comparisons of objects due to their data profile (the ordered set of values an object have). Hence, partial order methodology offers a unique possibility to evaluate analytical performance. In the present data as, e.g., provided by the laboratories through interlaboratory comparisons or proficiency testings is used as an illustrative example. However, the presented scheme is likewise applicable for comparison of analytical methods or simply as a tool for optimization of an analytical method. The methodology can be applied without presumptions or pretreatment of the analytical data provided in order to evaluate the analytical performance taking into account all indicators simultaneously and thus elucidating a "distance" from the true value. In the present illustrative example it is assumed that the laboratories analyze a given sample several times and subsequently report the mean value, the standard deviation and the skewness, which simultaneously are used for the evaluation of the analytical performance. The analyses lead to information concerning (1) a partial ordering of the laboratories, subsequently, (2) a "distance" to the Reference laboratory and (3) a classification due to the concept of "peculiar points". Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Ultramicroelectrode Array Based Sensors: A Promising Analytical Tool for Environmental Monitoring

    PubMed Central

    Orozco, Jahir; Fernández-Sánchez, César; Jiménez-Jorquera, Cecilia

    2010-01-01

    The particular analytical performance of ultramicroelectrode arrays (UMEAs) has attracted a high interest by the research community and has led to the development of a variety of electroanalytical applications. UMEA-based approaches have demonstrated to be powerful, simple, rapid and cost-effective analytical tools for environmental analysis compared to available conventional electrodes and standardised analytical techniques. An overview of the fabrication processes of UMEAs, their characterization and applications carried out by the Spanish scientific community is presented. A brief explanation of theoretical aspects that highlight their electrochemical behavior is also given. Finally, the applications of this transducer platform in the environmental field are discussed. PMID:22315551

  16. SERS-based application in food analytics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Cialla-May, Dana; Radu, Andreea; Jahn, Martin; Weber, Karina; Popp, Jürgen

    2017-02-01

    To establish detection schemes in life science applications, specific and sensitive methods allowing for fast detection times are required. Due to the interaction of molecules with strong electromagnetic fields excited at metallic nanostructures, the molecular fingerprint specific Raman spectrum is increased by several orders of magnitude. This effect is described as surface-enhanced Raman spectroscopy (SERS) and became a very powerful analytical tool in many fields of application. Within this presentation, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer. To do so, the food colorant Sudan III, an indirect carcinogen substance found in chili powder, palm oil or spice mixtures, is detected quantitatively in the background of the competitor riboflavin as well as paprika powder extracts. The SERS-based detection of azorubine (E122) in commercial available beverages with different complexity (e.g. sugar content, alcohol concentration) illustrates the strong potential of SERS as a qualitative as well as semiquantitative prescan method in food analytics. Here, a good agreement between the estimated concentration employing SERS as well as the gold standard technique HPLC, a highly laborious method, is found. Finally, SERS is applied to detect vitamin B2 and B12 in cereals as well as the estimate the ratio of lycopene and β-carotene in tomatoes. Acknowledgement: Funding the projects "QuantiSERS" and "Jenaer Biochip Initiative 2.0" within the framework "InnoProfile Transfer - Unternehmen Region" the Federal Ministry of Education and Research, Germany (BMBF) is gratefully acknowledged.

  17. Heat and mass transfer in combustion - Fundamental concepts and analytical techniques

    NASA Technical Reports Server (NTRS)

    Law, C. K.

    1984-01-01

    Fundamental combustion phenomena and the associated flame structures in laminar gaseous flows are discussed on physical bases within the framework of the three nondimensional parameters of interest to heat and mass transfer in chemically-reacting flows, namely the Damkoehler number, the Lewis number, and the Arrhenius number which is the ratio of the reaction activation energy to the characteristic thermal energy. The model problems selected for illustration are droplet combustion, boundary layer combustion, and the propagation, flammability, and stability of premixed flames. Fundamental concepts discussed include the flame structures for large activation energy reactions, S-curve interpretation of the ignition and extinctin states, reaction-induced local-similarity and non-similarity in boundary layer flows, the origin and removal of the cold boundary difficulty in modeling flame propagation, and effects of flame stretch and preferential diffusion on flame extinction and stability. Analytical techniques introduced include the Shvab-Zeldovich formulation, the local Shvab-Zeldovich formulation, flame-sheet approximation and the associated jump formulation, and large activation energy matched asymptotic analysis. Potentially promising research areas are suggested.

  18. Heat and mass transfer in combustion - Fundamental concepts and analytical techniques

    NASA Technical Reports Server (NTRS)

    Law, C. K.

    1984-01-01

    Fundamental combustion phenomena and the associated flame structures in laminar gaseous flows are discussed on physical bases within the framework of the three nondimensional parameters of interest to heat and mass transfer in chemically-reacting flows, namely the Damkoehler number, the Lewis number, and the Arrhenius number which is the ratio of the reaction activation energy to the characteristic thermal energy. The model problems selected for illustration are droplet combustion, boundary layer combustion, and the propagation, flammability, and stability of premixed flames. Fundamental concepts discussed include the flame structures for large activation energy reactions, S-curve interpretation of the ignition and extinctin states, reaction-induced local-similarity and non-similarity in boundary layer flows, the origin and removal of the cold boundary difficulty in modeling flame propagation, and effects of flame stretch and preferential diffusion on flame extinction and stability. Analytical techniques introduced include the Shvab-Zeldovich formulation, the local Shvab-Zeldovich formulation, flame-sheet approximation and the associated jump formulation, and large activation energy matched asymptotic analysis. Potentially promising research areas are suggested.

  19. Assessment of analytical techniques for predicting solid propellant exhaust plumes and plume impingement environments

    NASA Technical Reports Server (NTRS)

    Tevepaugh, J. A.; Smith, S. D.; Penny, M. M.

    1977-01-01

    An analysis of experimental nozzle, exhaust plume, and exhaust plume impingement data is presented. The data were obtained for subscale solid propellant motors with propellant Al loadings of 2, 10 and 15% exhausting to simulated altitudes of 50,000, 100,000 and 112,000 ft. Analytical predictions were made using a fully coupled two-phase method of characteristics numerical solution and a technique for defining thermal and pressure environments experienced by bodies immersed in two-phase exhaust plumes.

  20. Analytical evaluation of jet noise source location technique utilizing an acoustically hard baffle with aperture

    NASA Technical Reports Server (NTRS)

    Norum, T. D.; Mcdaid, E. P.

    1972-01-01

    An analytical investigation was conducted on the experimental technique that uses shielding by an acoustically hard baffle to determine the location of noise sources in a jet. The jet exhausts through a circular hole in the baffle and the radiated acoustic power is considered to be generated by a distributed source along the jet axis. It is found that the effect of the baffle on the radiated power can be neglected only when the size of the source is on the order of a wavelength of the emitted sound or larger. Since noise sources in a jet are compact, the experimental technique is insufficient to identify these sources.

  1. A review of analytical techniques for gait data. Part 1: Fuzzy, statistical and fractal methods.

    PubMed

    Chau, T

    2001-02-01

    In recent years, several new approaches to gait data analysis have been explored, including fuzzy systems, multivariate statistical techniques and fractal dynamics. Through a critical survey of recent gait studies, this paper reviews the potential of these methods to strengthen the gait laboratory's analytical arsenal. It is found that time-honoured multivariate statistical methods are the most widely applied and understood. Although initially promising, fuzzy and fractal analyses of gait data remain largely unknown and their full potential is yet to be realized. The trend towards fusing multiple techniques in a given analysis means that additional research into the application of these two methods will benefit gait data analysis.

  2. New test techniques and analytical procedures for understanding the behavior of advanced propellers

    NASA Technical Reports Server (NTRS)

    Stefko, G. L.; Bober, L. J.; Neumann, H. E.

    1983-01-01

    Analytical procedures and experimental techniques were developed to improve the capability to design advanced high speed propellers. Some results from the propeller lifting line and lifting surface aerodynamic analysis codes are compared with propeller force data, probe data and laser velocimeter data. In general, the code comparisons with data indicate good qualitative agreement. A rotating propeller force balance demonstrated good accuracy and reduced test time by 50 percent. Results from three propeller flow visualization techniques are shown which illustrate some of the physical phenomena occurring on these propellers.

  3. A Meta-Analytic Review of School-Based Prevention for Cannabis Use

    ERIC Educational Resources Information Center

    Porath-Waller, Amy J.; Beasley, Erin; Beirness, Douglas J.

    2010-01-01

    This investigation used meta-analytic techniques to evaluate the effectiveness of school-based prevention programming in reducing cannabis use among youth aged 12 to 19. It summarized the results from 15 studies published in peer-reviewed journals since 1999 and identified features that influenced program effectiveness. The results from the set of…

  4. A Meta-Analytic Review of the Role of Instructional Support in Game-Based Learning

    ERIC Educational Resources Information Center

    Wouters, Pieter; van Oostendorp, Herre

    2013-01-01

    Computer games can be considered complex learning environments in which players require instructional support to engage in cognitive processes such as selecting and actively organizing/integrating new information. We used meta-analytical techniques to test if instructional support enhances learning in game-based learning (k = 107, N[subscript adj]…

  5. Role of Knowledge Management and Analytical CRM in Business: Data Mining Based Framework

    ERIC Educational Resources Information Center

    Ranjan, Jayanthi; Bhatnagar, Vishal

    2011-01-01

    Purpose: The purpose of the paper is to provide a thorough analysis of the concepts of business intelligence (BI), knowledge management (KM) and analytical CRM (aCRM) and to establish a framework for integrating all the three to each other. The paper also seeks to establish a KM and aCRM based framework using data mining (DM) techniques, which…

  6. Role of Knowledge Management and Analytical CRM in Business: Data Mining Based Framework

    ERIC Educational Resources Information Center

    Ranjan, Jayanthi; Bhatnagar, Vishal

    2011-01-01

    Purpose: The purpose of the paper is to provide a thorough analysis of the concepts of business intelligence (BI), knowledge management (KM) and analytical CRM (aCRM) and to establish a framework for integrating all the three to each other. The paper also seeks to establish a KM and aCRM based framework using data mining (DM) techniques, which…

  7. A Meta-Analytic Review of School-Based Prevention for Cannabis Use

    ERIC Educational Resources Information Center

    Porath-Waller, Amy J.; Beasley, Erin; Beirness, Douglas J.

    2010-01-01

    This investigation used meta-analytic techniques to evaluate the effectiveness of school-based prevention programming in reducing cannabis use among youth aged 12 to 19. It summarized the results from 15 studies published in peer-reviewed journals since 1999 and identified features that influenced program effectiveness. The results from the set of…

  8. SIFT - A Component-Based Integration Architecture for Enterprise Analytics

    SciTech Connect

    Thurman, David A.; Almquist, Justin P.; Gorton, Ian; Wynne, Adam S.; Chatterton, Jack

    2007-02-01

    Architectures and technologies for enterprise application integration are relatively mature, resulting in a range of standards-based and proprietary middleware technologies. In the domain of complex analytical applications, integration architectures are not so well understood. Analytical applications such as those used in scientific discovery, emergency response, financial and intelligence analysis exert unique demands on their underlying architecture. These demands make existing integration middleware inappropriate for use in enterprise analytics environments. In this paper we describe SIFT (Scalable Information Fusion and Triage), a platform designed for integrating the various components that comprise enterprise analytics applications. SIFT exploits a common pattern for composing analytical components, and extends an existing messaging platform with dynamic configuration mechanisms and scaling capabilities. We demonstrate the use of SIFT to create a decision support platform for quality control based on large volumes of incoming delivery data. The strengths of the SIFT solution are discussed, and we conclude by describing where further work is required to create a complete solution applicable to a wide range of analytical application domains.

  9. Various extraction and analytical techniques for isolation and identification of secondary metabolites from Nigella sativa seeds.

    PubMed

    Liu, X; Abd El-Aty, A M; Shim, J-H

    2011-10-01

    Nigella sativa L. (black cumin), commonly known as black seed, is a member of the Ranunculaceae family. This seed is used as a natural remedy in many Middle Eastern and Far Eastern countries. Extracts prepared from N. sativa have, for centuries, been used for medical purposes. Thus far, the organic compounds in N. sativa, including alkaloids, steroids, carbohydrates, flavonoids, fatty acids, etc. have been fairly well characterized. Herein, we summarize some new extraction techniques, including microwave assisted extraction (MAE) and supercritical extraction techniques (SFE), in addition to the classical method of hydrodistillation (HD), which have been employed for isolation and various analytical techniques used for the identification of secondary metabolites in black seed. We believe that some compounds contained in N. sativa remain to be identified, and that high-throughput screening could help to identify new compounds. A study addressing environmentally-friendly techniques that have minimal or no environmental effects is currently underway in our laboratory.

  10. Combination of electrochemical, spectrometric and other analytical techniques for high throughput screening of pharmaceutically active compounds.

    PubMed

    Suzen, Sibel; Ozkan, Sibel A

    2010-08-01

    Recently, use of electrochemistry and combination of this method with spectroscopic and other analytical techniques are getting one of the important approaches in drug discovery and research as well as quality control, drug stability, determination of physiological activity, measurement of neurotransmitters. Many fundamental physiological processes are depending on oxido-reduction reactions in the body. Therefore, it may be possible to find connections between electrochemical and biochemical reactions concerning electron transfer pathways. Applications of electrochemical techniques to redox-active drug development and studies are one of the recent interests in drug discovery. In this review, the latest developments related to the use of electrochemical techniques in drug research in order to evaluate possible combination spectrometric methods with electrochemical techniques.

  11. Insight into Metalized Interfaces in Nano Devices by Surface Analytical Techniques.

    PubMed

    Xiang, Qing-Yun; Zhang, Kai; Wang, Yu; Lou, Xiao-Jie; Yao, Wen-Qing; Bai, Yang; Duan, Da-Wei; Hu, Xiao-Pei; Wang, Jie; Luo, Zheng-Dong; Wang, Huan-Hua; Zhang, Lin-Xing; Klemradt, Uwe; Cao, Jiang-Li

    2015-12-16

    Connections between metals and heterogeneous solid state materials form buried interfaces. These ubiquitous structures play an essential role in determining the performances of many nano- and microdevices. However, the information about the chemistry, structure, and properties of these real interfaces is intrinsically difficult to extract by traditional techniques. Therefore, approaches to efficiently discovering metalized interfaces are in high demand. Here, we demonstrate the transformation of nanoscale metal/oxide interface problems into surface problems through a novel metal-hydrogenation detaching method. We applied this technique to study the thickness dependence in Pb(Zr,Ti)O3 (PZT) ferroelectric thin films, a long-standing interface problem in a model metal/insulator device, and this allowed comprehensive surface analytical techniques to be adapted. A nonstoichiometric interfacial layer of 4.1 nm thick with low mass density, low permittivity, and weak ferroelectricity was quantified at the Pt/PZT interface and attributed to the preferential diffusions among the compositional elements. Targeted interface engineering by Pb rebalance led to a substantial recovery of ferroelectric properties. Our results therefore pave the way to a better understanding of metallized interface in ferroelectric and dielectric nanodevices. We hope that more useful information about metalized interfaces of other solid materials could, analogously, be accessed by surface analytical techniques.

  12. Process analytical techniques for hot-melt extrusion and their application to amorphous solid dispersions.

    PubMed

    Hitzer, Patrick; Bäuerle, Tim; Drieschner, Tobias; Ostertag, Edwin; Paulsen, Katharina; van Lishaut, Holger; Lorenz, Günter; Rebner, Karsten

    2017-07-01

    Newly developed active pharmaceutical ingredients (APIs) are often poorly soluble in water. As a result the bioavailability of the API in the human body is reduced. One approach to overcome this restriction is the formulation of amorphous solid dispersions (ASDs), e.g., by hot-melt extrusion (HME). Thus, the poorly soluble crystalline form of the API is transferred into a more soluble amorphous form. To reach this aim in HME, the APIs are embedded in a polymer matrix. The resulting amorphous solid dispersions may contain small amounts of residual crystallinity and have the tendency to recrystallize. For the controlled release of the API in the final drug product the amount of crystallinity has to be known. This review assesses the available analytical methods that have been recently used for the characterization of ASDs and the quantification of crystalline API content. Well-established techniques like near- and mid-infrared spectroscopy (NIR and MIR, respectively), Raman spectroscopy, and emerging ones like UV/VIS, terahertz, and ultrasonic spectroscopy are considered in detail. Furthermore, their advantages and limitations are discussed with regard to general practical applicability as process analytical technology (PAT) tools in industrial manufacturing. The review focuses on spectroscopic methods which have been proven as most suitable for in-line and on-line process analytics. Further aspects are spectroscopic techniques that have been or could be integrated into an extruder.

  13. Hyphenated techniques: The next generation of field-portable analytical instruments?

    SciTech Connect

    Meuzelaar, H.L.C.; McClennen, W.H.; Dworzanski, J.P.; Sheya, S.A.; Snyder, A.P.; Harden, C.S.; Arnold, N.S.

    1995-12-31

    The first field-portable (i.e., transportable) hyphenated analytical instruments, including commercially available MS/MS and GC/MS systems as well as a specially built GC/MS{sup n} introduced during the past seven years. Since then further miniaturization and ruggedization of hyphenated systems by several laboratories has resulted in fully man-portable (backpack and briefcase style) GC/MS systems and a hand portable GC/IMS prototype. The main pitfall to be avoided in developing hyphenated, field portable system is incompatibility between the coupled techniques. Carefully designed hyphenated techniques incorporating compatible methods such as GC and MS can provide dramatic increases in resolution and chemical specificity which may be traded for speed or sensitivity gains, if needed. Novel developments currently underway in the laboratory include roving GC/MS platforms, personalized GC/IMS devices, high speed GC/GC methods and, last but not least, Virtual Reality techniques.

  14. In Situ Ion-Transmission Mass Spectrometry for Paper-Based Analytical Devices.

    PubMed

    Zhao, Yaoyao; Wei, Zhenwei; Zhao, Hansen; Jia, Jia; Chen, Zhenzhen; Zhang, Sichun; Ouyang, Zheng; Ma, Xiaoxiao; Zhang, Xinrong

    2016-11-15

    Current detection methods for paper-based analytical devices (PADs) rely on spectroscopic and electrochemical properties, which place special requirements on the analyte or need analyte labeling. Here, ion-transmission mass spectrometry (MS) was proposed for coupling with PADs to enable rapid in situ MS analysis of the sample on paper. The sample was analyzed directly on paper via analyte ionization by ions transmitted through the paper, generated by a low-temperature plasma probe. Prior to MS analysis, the sample can be separated by paper electrophoresis or by paper chromatography, among a variety of other features offered by PADs. The versatility of this technique was demonstrated by MS analysis of a paper microarray, a mixture of amino acids, and whole blood doped with drugs on PADs.

  15. Prompt nuclear analytical techniques for material research in accelerator driven transmutation technologies: Prospects and quantitative analyses

    NASA Astrophysics Data System (ADS)

    Vacík, J.; Hnatowicz, V.; Červená, J.; Peřina, V.; Mach, R.; Peka, I.

    1998-04-01

    Accelerator driven transmutation technology (ADTT) is a promissing way toward liquidation of spent nuclear fuel, nuclear wastes and weapon grade Pu. The ADTT facility comprises a high current (proton) accelerator supplying a subcritical reactor assembly with spallation neutrons. The reactor part is supposed to be cooled by molten fluorides or metals which serve, at the same time, as a carrier of nuclear fuel. Assumed high working temperature (400-600°C) and high radiation load in the subcritical reactor and spallation neutron source put forward the problem of optimal choice of ADTT construction materials, especially from the point of their radiation and corrosion resistance when in contact with liquid working media. The use of prompt nuclear analytical techniques in ADTT related material research is considered and examples of preliminary analytical results obtained using neutron depth profiling method are shown for illustration.

  16. A comparison of analytical techniques for evaluating food waste degradation by anaerobic digestion.

    PubMed

    Gómez, X; Cuetos, M J; Tartakovsky, B; Martínez-Núñez, M F; Morán, A

    2010-05-01

    Organic matter contained in food waste was degraded by anaerobic digestion under mesophilic and thermophilic conditions at two hydraulic retention times. Evolution of the digestion process was followed by thermogravimetry analysis, fluorescence spectroscopy and (1)H nuclear magnetic resonance. All analytical methods suggested that longer retention times might be required for food waste stabilization under mesophilic conditions as compared to thermophilic stabilization. All the analytical methods showed that the stabilization process consisted of two steps, where complex organic molecules were formed during initial stabilization and then digested providing sufficient hydraulic retention time. Longer hydraulic retention times were required for food waste stabilization under mesophilic conditions. Overall, thermal and (1)H NMR analyses of the digestate samples might be recommended if more detailed analysis is required, while fluorescence measurements can be used as a fast screening technique, which provides qualitative assessment of the stabilization process.

  17. MS-based analytical methodologies to characterize genetically modified crops.

    PubMed

    García-Cañas, Virginia; Simó, Carolina; León, Carlos; Ibáñez, Elena; Cifuentes, Alejandro

    2011-01-01

    The development of genetically modified crops has had a great impact on the agriculture and food industries. However, the development of any genetically modified organism (GMO) requires the application of analytical procedures to confirm the equivalence of the GMO compared to its isogenic non-transgenic counterpart. Moreover, the use of GMOs in foods and agriculture faces numerous criticisms from consumers and ecological organizations that have led some countries to regulate their production, growth, and commercialization. These regulations have brought about the need of new and more powerful analytical methods to face the complexity of this topic. In this regard, MS-based technologies are increasingly used for GMOs analysis to provide very useful information on GMO composition (e.g., metabolites, proteins). This review focuses on the MS-based analytical methodologies used to characterize genetically modified crops (also called transgenic crops). First, an overview on genetically modified crops development is provided, together with the main difficulties of their analysis. Next, the different MS-based analytical approaches applied to characterize GM crops are critically discussed, and include "-omics" approaches and target-based approaches. These methodologies allow the study of intended and unintended effects that result from the genetic transformation. This information is considered to be essential to corroborate (or not) the equivalence of the GM crop with its isogenic non-transgenic counterpart. Copyright © 2010 Wiley Periodicals, Inc.

  18. A physically based analytical spatial air temperature and humidity model

    Treesearch

    Yang Yang; Theodore A. Endreny; David J. Nowak

    2013-01-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat...

  19. An overview to nano-scale analytical techniques: Nano-liquid chromatography and capillary electrochromatography.

    PubMed

    Fanali, Salvatore

    2017-08-01

    Nano-liquid chromatography (nano-LC) and CEC are microfluidic techniques mainly used for analytical purposes. They have been applied to the separation and analysis of a large number of compounds, e.g., peptides, proteins, drugs, enantiomers, antibiotics, pesticides, nutraceutical, etc. Analytes separation is carried out into capillaries containing selected stationary phase. The mobile phase is moved either by a pump (nano-LC) or by an EOF, respectively. The two tools can offer some advantages over conventional techniques, e.g., high selectivity, separation efficiency, resolution, short analysis time and consumption of low volumes of mobile phase. Flow rates in the range 50-800 nL/min are usually applied. The low flow rate reduces the chromatographic dilution increasing the mass sensitivity. Special attention must be paid in avoiding peak dispersion selecting the appropriate detector, injector and tube connection. Finally due to the low flow rate these microfluidic techniques can be easily coupled with mass spectrometry. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Comparison of analytical techniques for purity evaluation of single-walled carbon nanotubes.

    PubMed

    Itkis, Mikhail E; Perea, Daniel E; Jung, Richard; Niyogi, Sandip; Haddon, Robert C

    2005-03-16

    We compare popular analytical techniques, including scanning and transmission electron microscopy (SEM and TEM), thermogravimetric analysis (TGA), and Raman and near-infrared (NIR) spectroscopy, for the evaluation of the purity of bulk quantities of single-walled carbon nanotubes (SWNTs). Despite their importance as imaging techniques, SEM and TEM are not capable of quantitatively evaluating the purity of typical inhomogeneous bulk SWNT samples because the image frame visualizes less than 1 pg of SWNT material; furthermore, there is no published algorithm to convert such images into numerical data. The TGA technique is capable of measuring the amount of metal catalyst in an SWNT sample, but does not provide an unambiguous separation between the content of SWNTs and carbonaceous impurities. We discuss the utilization of solution-phase near-infrared spectroscopy and solution-phase Raman spectroscopy to quantitatively compare arbitrary samples of bulk SWNT materials of different purities. The primary goal of this paper is to provide the chemical community with a realistic evaluation of current analytical tools for the purity evaluation of a bulk sample of SWNTs. The secondary goal is to draw attention to the growing crisis in the SWNT industry as a result of the lack of quality control and the misleading advertising by suppliers of this material.

  1. Recent progress on fully analytic mesh based computer-generated holography

    NASA Astrophysics Data System (ADS)

    Park, Jae-Hyeung

    2016-10-01

    Computer generated holography plays a main role in the contents generation for holographic displays and digital archiving of three-dimensional objects. The fully analytic mesh based computer generated holography finds exact complex optical field for each triangular mesh of the three-dimensional objects for given sampling interval in the hologram plane without any approximation, enhancing the quality of the reconstruction. The mesh based processing rather than conventional point based one makes it compatible with most computer graphics techniques and efficient especially for large objects. In this paper, we present a few recent progress on fully analytic mesh based computer generated holography techniques including the dark line artifact removal, continuous shading of each mesh surface, the implementation of the angular reflectance distribution of the object surface and application of the texture map.

  2. A Study on Gravimetric Geoid Determination Using Analytical Downward Continuation Technique

    NASA Astrophysics Data System (ADS)

    Sezen, Erdinç; Doǧan, Uǧur; Yıldız, Hasan

    2016-04-01

    The Stokes' formula requires the gravity anomaly on the Earth's surface be downward continued to the geoid and the mass above the geoid be removed. Although the Earth Gravity Field Models (EGMs) are used to compute quasi geoid models, gravimetric geoid determination is possible taking into account the topographic effects. Analytical or harmonic downward continuation of external gravity potential of the Earth into the topographic masses results in "analytical downward continuation error" or "topographic bias". One of the alternatives to compute topographic bias is spherical harmonic expansion of reciprocal distance including functional coefficients of Earth's radius and topographic height depending on the position. Spherical harmonic coefficients are then expanded into binomial series to compute the difference between the topographical potential and its downward continuation. On any coordinates on the Earth, topographic bias can easily be computed using these coefficients. Topographic bias provides a practical way to compute a regional geoid model transforming height anomalies computed from EGMs to geoid undulations. Using this technique, regional geoid models are determined in two test areas, the Auvergne, France and New Mexico, U.S.A, and compared with the GNSS/levelling geoid undulations and the regional geoid models computed using Least Squares Modification of Stokes' Formula (KTH method). Keywords: Analytical downward continuation, topographic bias, geoid determination, Earth Gravity Model, Least Squares Modification of Stokes' Formula (KTH method).

  3. Evaluation of available analytical techniques for monitoring the quality of space station potable water

    NASA Technical Reports Server (NTRS)

    Geer, Richard D.

    1989-01-01

    To assure the quality of potable water (PW) on the Space Station (SS) a number of chemical and physical tests must be conducted routinely. After reviewing the requirements for potable water, both direct and indirect analytical methods are evaluated that could make the required tests and improvements compatible with the Space Station operation. A variety of suggestions are made to improve the analytical techniques for SS operation. The most important recommendations are: (1) the silver/silver chloride electrode (SB) method of removing I sub 2/I (-) biocide from the water, since it may interfere with analytical procedures for PW and also its end uses; (2) the orbital reactor (OR) method of carrying out chemistry and electrochemistry in microgravity by using a disk shaped reactor on an orbital table to impart artificial G force to the contents, allowing solution mixing and separation of gases and liquids; and (3) a simple ultra low volume highly sensitive electrochemical/conductivity detector for use with a capillary zone electrophoresis apparatus. It is also recommended, since several different conductivity and resistance measurements are made during the analysis of PW, that the bipolar pulse measuring circuit be used in all these applications for maximum compatibility and redundancy of equipment.

  4. Selenoproteins: the key factor in selenium essentiality. State of the art analytical techniques for selenoprotein studies.

    PubMed

    Lopez Heras, Isabel; Palomo, Maria; Madrid, Yolanda

    2011-06-01

    Selenium is an essential element for human health. The benefits of selenium are many including protection against cancer, heart diseases and other cardiovascular and muscle disorders. Selenium is also helpful in controlling gastrointestinal disorders, enhancing immunity of the human body and reducing age-related diseases. The health-promoting properties of Se are due to vital functions of selenoproteins in which selenium is present as selenocysteine, the 21st amino acid. To date, dozens of selenoprotein families have been described though many have roles that have not been fully elucidated. Selenoproteins research has attracted tremendous interest from different scientific areas. Analytical chemists have not remained indifferent to the attractive features of these unique proteins. Different analytical techniques, such as multidimensional chromatography-inductively coupled plasma mass spectrometry (ICPMS), electrospray (tandem) mass spectrometry (ESI-MS/MS), matrix-assisted laser desorption ionization time-of flight (MALDI-TOF) and sodium dodecyl sulphate polyacrylamide gel electrophoresis-laser ablation inductively coupled plasma mass spectrometry (SDS-PAGE-LA-ICPMS), have been applied to the determination of selenoproteins and selenium-containing proteins. This review describes the best-characterized selenoproteins to date in addition to the major contributions of analytical chemistry to the field of selenoproteins. The article also highlights the challenges of combining elemental and molecular mass spectrometry for the determination of selenoproteins and selenium-containing proteins.

  5. Standardization of chemical analytical techniques for pyrolysis bio-oil: history, challenges, and current status of methods: Bio-oil Analytical Standardization

    SciTech Connect

    Ferrell, Jack R.; Olarte, Mariefel V.; Christensen, Earl D.; Padmaperuma, Asanga B.; Connatser, Raynella M.; Stankovikj, Filip; Meier, Dietrich; Paasikallio, Ville

    2016-07-05

    In this perspective, we discuss the standardization of analytical techniques for pyrolysis bio-oils, including the current status of methods, and our opinions on future directions. First, the history of past standardization efforts is summarized, and both successful and unsuccessful validation of analytical techniques highlighted. The majority of analytical standardization studies to-date has tested only physical characterization techniques. Here, we present results from an international round robin on the validation of chemical characterization techniques for bio-oils. Techniques tested included acid number, carbonyl titrations using two different methods (one at room temperature and one at 80 degrees C), 31P NMR for determination of hydroxyl groups, and a quantitative gas chromatography-mass spectrometry (GC-MS) method. Both carbonyl titration and acid number methods have yielded acceptable inter-laboratory variabilities. 31P NMR produced acceptable results for aliphatic and phenolic hydroxyl groups, but not for carboxylic hydroxyl groups. As shown in previous round robins, GC-MS results were more variable. Reliable chemical characterization of bio-oils will enable upgrading research and allow for detailed comparisons of bio-oils produced at different facilities. Reliable analytics are also needed to enable an emerging bioenergy industry, as processing facilities often have different analytical needs and capabilities than research facilities. We feel that correlations in reliable characterizations of bio-oils will help strike a balance between research and industry, and will ultimately help to determine metrics for bio-oil quality. Finally, the standardization of additional analytical methods is needed, particularly for upgraded bio-oils.

  6. Application of nuclear analytical techniques to biological and environmental research in the Czech Republic

    SciTech Connect

    Kucera, J.

    1996-12-31

    There is a long tradition in radiochemistry in the present Czech Republic that dates from 1856. However, the modern history of nuclear analytical techniques (NAT) development started after installation of the first experimental nuclear reactor and Van de Graaff accelerator in the mid-sixties at Rez. Since then, the NAT, such as neutron activation analysis (NAA) both instrumental (INAA) and radiochemical (RNAA), gamma activation analysis, particle-induced X-ray and gamma-ray emission (PIXE and PIGE, respectively), Rutherford backscattering, and neutron depth profiling have been continuously developed and applied in various scientific and technological fields. The radiochemical approach has always had a strong position in these investigations and resulted in the discovery of the substoichiometry separation principle in NAA and isotope dilution techniques and extensive utilization of RNAA. The use of INAA and RNAA in the evaluation of biological and environmental materials as well as plants is described.

  7. Recent trends in analytical methods and separation techniques for drugs of abuse in hair.

    PubMed

    Baciu, T; Borrull, F; Aguilar, C; Calull, M

    2015-01-26

    Hair analysis of drugs of abuse has been a subject of growing interest from a clinical, social and forensic perspective for years because of the broad time detection window after intake in comparison to urine and blood analysis. Over the last few years, hair analysis has gained increasing attention and recognition for the retrospective investigation of drug abuse in a wide variety of contexts, shown by the large number of applications developed. This review aims to provide an overview of the state of the art and the latest trends used in the literature from 2005 to the present in the analysis of drugs of abuse in hair, with a special focus on separation analytical techniques and their hyphenation with mass spectrometry detection. The most recently introduced sample preparation techniques are also addressed in this paper. The main strengths and weaknesses of all of these approaches are critically discussed by means of relevant applications.

  8. An analytical technique for approximating unsteady aerodynamics in the time domain

    NASA Technical Reports Server (NTRS)

    Dunn, H. J.

    1980-01-01

    An analytical technique is presented for approximating unsteady aerodynamic forces in the time domain. The order of elements of a matrix Pade approximation was postulated, and the resulting polynomial coefficients were determined through a combination of least squares estimates for the numerator coefficients and a constrained gradient search for the denominator coefficients which insures stable approximating functions. The number of differential equations required to represent the aerodynamic forces to a given accuracy tends to be smaller than that employed in certain existing techniques where the denominator coefficients are chosen a priori. Results are shown for an aeroelastic, cantilevered, semispan wing which indicate a good fit to the aerodynamic forces for oscillatory motion can be achieved with a matrix Pade approximation having fourth order numerator and second order denominator polynomials.

  9. Analytical techniques for characterization of raw materials in cell culture media.

    PubMed

    Sharma, Chandana; Drew, Barry; Head, Kevin; Pusuluri, Rani; Caple, Matthew V

    2011-01-01

    Raw materials are a critical part of any cell culture medium; therefore, it is of utmost importance to understand and characterize them for high-quality product. The raw material characterization (RMC) program at SAFC focuses on individual screening of raw materials both analytically and biologically. The goal of the program is to develop the best-in-class knowledge base of the raw materials used in SAFC's media formulations and their impact on performance of products.

  10. Analytical techniques for characterization of raw materials in cell culture media

    PubMed Central

    2011-01-01

    Raw materials are a critical part of any cell culture medium; therefore, it is of utmost importance to understand and characterize them for high-quality product. The raw material characterization (RMC) program at SAFC focuses on individual screening of raw materials both analytically and biologically. The goal of the program is to develop the best-in-class knowledge base of the raw materials used in SAFC’s media formulations and their impact on performance of products. PMID:22373443

  11. Analytical characterization of cyclodextrins: History, official methods and recommended new techniques.

    PubMed

    Szente, Lajos; Szemán, Julianna; Sohajda, Tamás

    2016-10-25

    The main goal of this review is to provide a comprehensive overview on the methods used for analysis of cyclodextrins (CDs) and CD-derivatives. The paper intends to act as a guide for the readers in looking around the classical and modern instrumental analytical methods suitable for identification, characterization and determination of CDs themselves, CDs in finished products or even in biological samples. At present, in the European and United States Pharmacopoeias, the three parent CDs and two synthetic derivatives, namely the (2-hydroxypropyl)-beta-CD and sulfobutylether-beta-CD Na salt are official. Besides these modified CDs, two other derivatives are approved as excipients in human pharmaceutical products: the (2-hydroxypropyl)-gamma-CD and the randomly methylated-beta-CD. Although most of the official analysis methods in the pharmacopoeias have been well used for decades, new aspects of the functional excipient CD characterization suggest a need to revisit compendial methods. Comparison of strengths and weaknesses of current official methods with new improved techniques intends to help analysts to decide on changing traditional analytical methods with improved new ones. This review also deals with the analytical aspects of the first single isomer CD derivative approved as a drug active (Sugammadex/Bridion(®)) as well as analytical considerations of using CDs themselves as active pharmaceutical ingredients. Stability-indicating instrumental methods suitable to adequately follow chemical- and enzymatic degradation of CDs will also be discussed. Challenges in the determination of CDs in different biological matrices will be illustrated on real pharmaco- and toxicokinetic studies of CD-enabled drug formulations.

  12. Does leaf chemistry differentially affect breakdown in tropical vs temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Treesearch

    Marcelo Ard& #243; n; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to measure leaf chemistry. We used standardized analytical techniques to measure chemistry and breakdown rate of leaves from common riparian tree species at 2 sites, 1...

  13. New analytical expressions of the Rossiter-McLaughlin effect adapted to different observation techniques

    NASA Astrophysics Data System (ADS)

    Boué, G.; Montalto, M.; Boisse, I.; Oshagh, M.; Santos, N. C.

    2013-02-01

    The Rossiter-McLaughlin (hereafter RM) effect is a key tool for measuring the projected spin-orbit angle between stellar spin axes and orbits of transiting planets. However, the measured radial velocity (RV) anomalies produced by this effect are not intrinsic and depend on both instrumental resolution and data reduction routines. Using inappropriate formulas to model the RM effect introduces biases, at least in the projected velocity Vsini⋆ compared to the spectroscopic value. Currently, only the iodine cell technique has been modeled, which corresponds to observations done by, e.g., the HIRES spectrograph of the Keck telescope. In this paper, we provide a simple expression of the RM effect specially designed to model observations done by the Gaussian fit of a cross-correlation function (CCF) as in the routines performed by the HARPS team. We derived a new analytical formulation of the RV anomaly associated to the iodine cell technique. For both formulas, we modeled the subplanet mean velocity vp and dispersion βp accurately taking the rotational broadening on the subplanet profile into account. We compare our formulas adapted to the CCF technique with simulated data generated with the numerical software SOAP-T and find good agreement up to Vsini⋆ ≲ 20 km s-1. In contrast, the analytical models simulating the two different observation techniques can disagree by about 10σ in Vsini⋆ for large spin-orbit misalignments. It is thus important to apply the adapted model when fitting data. A public code implementing the expressions derived in this paper is available at http://www.astro.up.pt/resources/arome. A copy of the code is also available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/550/A53

  14. Comparison of analytical techniques for the determination of aldehydes in test chambers.

    PubMed

    Salthammer, Tunga; Mentese, Sibel

    2008-11-01

    The level of carbonyl compounds in indoor air is crucial due to possible health effects and the high prevalence of their potential sources. Therefore, selecting a convenient and rapid analytical technique for the reliable detection of carbonyl compound concentrations is important. The acetyl acetone (acac) method is a widely used standard procedure for detecting gaseous formaldehyde. For measuring formaldehyde along with other carbonyl compounds, the DNPH-method is commonly applied. The recommended procedure for measuring volatile organic compounds (VOCs) is sampling on Tenax TA, followed by thermal desorption and GC/MS analysis. In this study, different analytical techniques for the quantification of formaldehyde, pentanal, and hexanal are critically compared. It was found that the acac- and DNPH-method are in very good agreement for formaldehyde. In contrast, the DNPH-method significantly underestimates indoor air concentrations of the higher aldehydes in comparison to sampling on Tenax TA, although both methods are strongly correlated. The reported results are part of the EURIMA-WKI study on levels of indoor air pollutants resulting from construction, building materials and interior decoration.

  15. Microextraction techniques at the analytical laboratory: an efficient way for determining low amounts of residual insecticides in soils

    NASA Astrophysics Data System (ADS)

    Viñas, Pilar; Navarro, Tania; Campillo, Natalia; Fenoll, Jose; Garrido, Isabel; Cava, Juana; Hernandez-Cordoba, Manuel

    2017-04-01

    Microextraction techniques allow sensitive measurements of pollutants to be carried out by means of instrumentation commonly available at the analytical laboratory. This communication reports our studies focused to the determination of pyrethroid insecticides in polluted soils. These chemicals are synthetic analogues of pyrethrum widely used for pest control in agricultural and household applications. Because of their properties, pyrethroids tend to strongly absorb to soil particles and organic matter. Although they are considered as pesticides with a low toxicity for humans, long times exposure to them may cause damage in immune system and in the neurological system. The procedure here studied is based on dispersive liquid-liquid microextraction (DLLME), and permits the determination of fifteen pyrethroid compounds (allethrin, resmethrin, tetramethrin, bifenthrin, fenpropathrin, cyhalothrin, acrinathrin, permethrin, λ-cyfluthrin, cypermethrin, flucythrinate, fenvalerate, esfenvalerate, τ-fluvalinate, and deltamethrin) in soil samples using gas chromatography with mass spectrometry (GC-MS). The analytes were first extracted from the soil samples (4 g) by treatment with 2 mL of acetonitrile, 2 mL of water and 0.5 g of NaCl. The enriched organic phase (approximately 0.8 mL) was separated by centrifugation, and this solution used as the dispersant in a DLLME process. The analytes did not need to be derivatized before their injection into the chromatographic system, due to their volatility and thermal stability. The identification of the different pyrethroids was carried out based on their retention times and mass spectra, considering the m/z values of the different fragments and their relative abundances. The detection limits were in the 0.2-23 ng g-1 range, depending on the analyte and the sample under analysis. The authors are grateful to the Comunidad Autonóma de la Región de Murcia, Spain (Fundación Séneca, 19888/GERM/15) and to the Spanish MINECO (Project

  16. Differential linear scan voltammetry: analytical performance in comparison with pulsed voltammetry techniques.

    PubMed

    Sheth, Disha B; Gratzl, Miklós

    2013-06-01

    We report here on differential linear scan voltammetry, DLSV, that combines the working principles of linear scan voltammetry, LSV, and the numerous existing pulsed voltammetry techniques. DLSV preserves the information from continuous interrogation in voltage and high accuracy that LSV provides about electrochemical processes, and the much better sensitivity of differential pulsed techniques. DLSV also minimizes the background current compared to both LSV and pulsed voltammetry. An early version of DLSV, derivative stationary electrode polarography, DSEP, had been proposed in the 1960s but soon abandoned in favor of the emerging differential pulsed techniques. Relative to DSEP, DLSV takes advantage of the flexibility of discrete smoothing differentiation that was not available to early investigators. Also, DSEP had been explored in pure solutions and with reversible electrochemical reactions. DLSV is tested in this work in more challenging experimental contexts: the measurement of oxygen with a carbon fiber microelectrode in buffer, and with a gold microdisc electrode exposed to a live biological preparation. This work compares the analytical performance of DLSV and square wave voltammetry, the most popular pulsed voltammetry technique.

  17. Characterization and source identification of hydrocarbons in water samples using multiple analytical techniques.

    PubMed

    Wang, Zhendi; Li, K; Fingas, M; Sigouin, L; Ménard, L

    2002-09-20

    This paper describes a case study in which multiple analytical techniques were used to identify and characterize trace petroleum-related hydrocarbons and other volatile organic compounds in groundwater samples collected in a bedrock aquifer exploited for drinking water purposes. The objective of the study was to confirm the presence of gasoline and other petroleum products or other volatile organic pollutants in those samples in order to assess the respective implication of each of the potentially responsible parties to the contamination of the aquifer. In addition, the degree of contamination at different depths in the aquifer was also of interest. The analytical techniques used for analyses of water samples included gas chromatography-mass spectrometry (GC-MS) and capillary GC with flame-ionization detection, solid-phase microextraction and headspace GC-MS techniques. Chemical characterization results revealed the following: (1) The hydrocarbons in sample A (near-surface groundwater, 0-5 m) were clearly of two types, one being gasoline and the other a heavy petroleum product. The significant distribution of five target petroleum-characteristic alkylkated polycyclic aromatic hydrocarbon homologues and biomarkers confirmed the presence of another heavy petroleum product. The concentrations of the TPHs (total petroleum hydrocarbons) and BTEX (collective name of benzene, toluene, ethylbenzene, and p-, m-, and o-xylenes) were determined to be 1070 and 155 microg/kg of water for sample A, respectively. (2) The deepest groundwater (sample B, collected at a depth ranging between 15 and 60 m) was also contaminated, but to a much lesser degree. The concentrations of the TPH and BTEX were determined to be only 130 and 2.6 microg/kg of water for sample B, respectively. (3) The presence of a variety of volatile chlorinated compounds to the groundwater was also clearly identified.

  18. Big data analytics in immunology: a knowledge-based approach.

    PubMed

    Zhang, Guang Lan; Sun, Jing; Chitkushev, Lou; Brusic, Vladimir

    2014-01-01

    With the vast amount of immunological data available, immunology research is entering the big data era. These data vary in granularity, quality, and complexity and are stored in various formats, including publications, technical reports, and databases. The challenge is to make the transition from data to actionable knowledge and wisdom and bridge the knowledge gap and application gap. We report a knowledge-based approach based on a framework called KB-builder that facilitates data mining by enabling fast development and deployment of web-accessible immunological data knowledge warehouses. Immunological knowledge discovery relies heavily on both the availability of accurate, up-to-date, and well-organized data and the proper analytics tools. We propose the use of knowledge-based approaches by developing knowledgebases combining well-annotated data with specialized analytical tools and integrating them into analytical workflow. A set of well-defined workflow types with rich summarization and visualization capacity facilitates the transformation from data to critical information and knowledge. By using KB-builder, we enabled streamlining of normally time-consuming processes of database development. The knowledgebases built using KB-builder will speed up rational vaccine design by providing accurate and well-annotated data coupled with tailored computational analysis tools and workflow.

  19. Analytics4Action Evaluation Framework: A Review of Evidence-Based Learning Analytics Interventions at the Open University UK

    ERIC Educational Resources Information Center

    Rienties, Bart; Boroowa, Avinash; Cross, Simon; Kubiak, Chris; Mayles, Kevin; Murphy, Sam

    2016-01-01

    There is an urgent need to develop an evidence-based framework for learning analytics whereby stakeholders can manage, evaluate, and make decisions about which types of interventions work well and under which conditions. In this article, we will work towards developing a foundation of an Analytics4Action Evaluation Framework (A4AEF) that is…

  20. General Analytical Schemes for the Characterization of Pectin-Based Edible Gelled Systems

    PubMed Central

    Haghighi, Maryam; Rezaei, Karamatollah

    2012-01-01

    Pectin-based gelled systems have gained increasing attention for the design of newly developed food products. For this reason, the characterization of such formulas is a necessity in order to present scientific data and to introduce an appropriate finished product to the industry. Various analytical techniques are available for the evaluation of the systems formulated on the basis of pectin and the designed gel. In this paper, general analytical approaches for the characterization of pectin-based gelled systems were categorized into several subsections including physicochemical analysis, visual observation, textural/rheological measurement, microstructural image characterization, and psychorheological evaluation. Three-dimensional trials to assess correlations among microstructure, texture, and taste were also discussed. Practical examples of advanced objective techniques including experimental setups for small and large deformation rheological measurements and microstructural image analysis were presented in more details. PMID:22645484

  1. Lignocellulose-based analytical devices: bamboo as an analytical platform for chemical detection

    PubMed Central

    Kuan, Chen-Meng; York, Roger L.; Cheng, Chao-Min

    2015-01-01

    This article describes the development of lignocellulose-based analytical devices (LADs) for rapid bioanalysis in low-resource settings. LADs are constructed using either a single lignocellulose or a hybrid design consisting of multiple types of lignocellulose. LADs are simple, low-cost, easy to use, provide rapid response, and do not require external instrumentation during operation. Here, we demonstrate the implementation of LADs for food and water safety (i.e., nitrite assay in hot-pot soup, bacterial detection in water, and resazurin assay in milk) and urinalysis (i.e., nitrite, urobilinogen, and pH assays in human urine). Notably, we created a unique approach using simple chemicals to achieve sensitivity similar to that of commercially available immunochromatographic strips that is low-cost, and provides on-site, rapid detection, for instance, of Eschericia coli (E. coli) in water. PMID:26686576

  2. Review of recent advances in analytical techniques for the determination of neurotransmitters

    PubMed Central

    Perry, Maura; Li, Qiang; Kennedy, Robert T.

    2009-01-01

    Methods and advances for monitoring neurotransmitters in vivo or for tissue analysis of neurotransmitters over the last five years are reviewed. The review is organized primarily by neurotransmitter type. Transmitter and related compounds may be monitored by either in vivo sampling coupled to analytical methods or implanted sensors. Sampling is primarily performed using microdialysis, but low-flow push-pull perfusion may offer advantages of spatial resolution while minimizing the tissue disruption associated with higher flow rates. Analytical techniques coupled to these sampling methods include liquid chromatography, capillary electrophoresis, enzyme assays, sensors, and mass spectrometry. Methods for the detection of amino acid, monoamine, neuropeptide, acetylcholine, nucleoside, and soluable gas neurotransmitters have been developed and improved upon. Advances in the speed and sensitivity of these methods have enabled improvements in temporal resolution and increased the number of compounds detectable. Similar advances have enabled improved detection at tissue samples, with a substantial emphasis on single cell and other small samples. Sensors provide excellent temporal and spatial resolution for in vivo monitoring. Advances in application to catecholamines, indoleamines, and amino acids have been prominent. Improvements in stability, sensitivity, and selectivity of the sensors have been of paramount interest. PMID:19800472

  3. Applications of MEMS-based biochemical analytical instrumentation

    SciTech Connect

    Morse, J. D., LLNL

    1997-05-21

    The MicroTechnology Center at Lawrence Livermore National Laboratory is developing a variety of MEMS-Based analytical instrumentation systems in support of programmatic needs, along with numerous external customers. Several of the applications of interest are in the area of biochemical identification and analysis. These applications range from DNA fragment analysis and collection in support of the Human Genome Project, to detection of viruses or biological warfare agents. Each of the applications of interest has focused in micro-machined MEMS technology for reduced cost, higher throughput, and faster results. Development of these analytical instrumentation systems will have long term benefits for the medical community as well. The following describes the technologies several specific applications.

  4. Comparison of Analytic Hierarchy Process, Catastrophe and Entropy techniques for evaluating groundwater prospect of hard-rock aquifer systems

    NASA Astrophysics Data System (ADS)

    Jenifer, M. Annie; Jha, Madan K.

    2017-05-01

    Groundwater is a treasured underground resource, which plays a central role in sustainable water management. However, it being hidden and dynamic in nature, its sustainable development and management calls for precise quantification of this precious resource at an appropriate scale. This study demonstrates the efficacy of three GIS-based multi-criteria decision analysis (MCDA) techniques, viz., Analytic Hierarchy Process (AHP), Catastrophe and Entropy in evaluating groundwater potential through a case study in hard-rock aquifer systems. Using satellite imagery and relevant field data, eight thematic layers (rainfall, land slope, drainage density, soil, lineament density, geology, proximity to surface water bodies and elevation) of the factors having significant influence on groundwater occurrence were prepared. These thematic layers and their features were assigned suitable weights based on the conceptual frameworks of AHP, Catastrophe and Entropy techniques and then they were integrated in the GIS environment to generate an integrated raster layer depicting groundwater potential index of the study area. The three groundwater prospect maps thus yielded by these MCDA techniques were verified using a novel approach (concept of 'Dynamic Groundwater Potential'). The validation results revealed that the groundwater potential predicted by the AHP technique has a pronounced accuracy of 87% compared to the Catastrophe (46% accuracy) and Entropy techniques (51% accuracy). It is concluded that the AHP technique is the most reliable for the assessment of groundwater resources followed by the Entropy method. The developed groundwater potential maps can serve as a scientific guideline for the cost-effective siting of wells and the effective planning of groundwater development at a catchment or basin scale.

  5. Role of nuclear analytical probe techniques in biological trace element research

    SciTech Connect

    Jones, K.W.; Pounds, J.G.

    1985-01-01

    Many biomedical experiments require the qualitative and quantitative localization of trace elements with high sensitivity and good spatial resolution. The feasibility of measuring the chemical form of the elements, the time course of trace elements metabolism, and of conducting experiments in living biological systems are also important requirements for biological trace element research. Nuclear analytical techniques that employ ion or photon beams have grown in importance in the past decade and have led to several new experimental approaches. Some of the important features of these methods are reviewed here along with their role in trace element research, and examples of their use are given to illustrate potential for new research directions. It is emphasized that the effective application of these methods necessitates a closely integrated multidisciplinary scientific team. 21 refs., 4 figs., 1 tab.

  6. Margo and Me. II. The role of narrative building in child analytic technique.

    PubMed

    Knight, Rona

    2003-01-01

    Practicing child and adolescent psychoanalysis requires an understanding of the interdependence of analytic and developmental processes. Child analysts work with children whose organizing and regulating systems are still developing, allowing the analyst and her patient to tap the child's transformational potential as new hierarchies evolve and consolidate in the course of an analysis. The use of the narrative building technique is helpful to that process and is informed by and makes clinically applicable recent research data in development and therapeutic process. Narrative building can help the child develop phase specific organization that has been impeded by conflictual and non-conflictual elements in the child's inner and outer world, promote the developmental process, provide more flexible regulatory systems for emotional and cognitive development, lead to innovative views of people and relationships, and facilitate the organization of emerging structures necessary for progressive development.

  7. Screening of synthetic PDE-5 inhibitors and their analogues as adulterants: analytical techniques and challenges.

    PubMed

    Patel, Dhavalkumar Narendrabhai; Li, Lin; Kee, Chee-Leong; Ge, Xiaowei; Low, Min-Yong; Koh, Hwee-Ling

    2014-01-01

    The popularity of phosphodiesterase type 5 (PDE-5) enzyme inhibitors for the treatment of erectile dysfunction has led to the increase in prevalence of illicit sexual performance enhancement products. PDE-5 inhibitors, namely sildenafil, tadalafil and vardenafil, and their unapproved designer analogues are being increasingly used as adulterants in the herbal products and health supplements marketed for sexual performance enhancement. To date, more than 50 unapproved analogues of prescription PDE-5 inhibitors were found as adulterants in the literature. To avoid detection of such adulteration by standard screening protocols, the perpetrators of such illegal products are investing time and resources to synthesize exotic analogues and devise novel means for adulteration. A comprehensive review of conventional and advance analytical techniques to detect and characterize the adulterants is presented. The rapid identification and structural elucidation of unknown analogues as adulterants is greatly enhanced by the wide myriad of analytical techniques employed, including high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), liquid chromatography mass-spectrometry (LC-MS), nuclear magnetic resonance (NMR) spectroscopy, vibrational spectroscopy, liquid chromatography-Fourier transform ion cyclotron resonance-mass spectrometry (LC-FT-ICR-MS), liquid chromatograph-hybrid triple quadrupole linear ion trap mass spectrometer with information dependent acquisition, ultra high performance liquid chromatography-time of flight-mass spectrometry (UHPLC-TOF-MS), ion mobility spectroscopy (IMS) and immunoassay methods. The many challenges in detecting and characterizing such adulterants, and the need for concerted effort to curb adulteration in order to safe guard public safety and interest are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Nine-analyte detection using an array-based biosensor

    NASA Technical Reports Server (NTRS)

    Taitt, Chris Rowe; Anderson, George P.; Lingerfelt, Brian M.; Feldstein, s. Mark. J.; Ligler, Frances S.

    2002-01-01

    A fluorescence-based multianalyte immunosensor has been developed for simultaneous analysis of multiple samples. While the standard 6 x 6 format of the array sensor has been used to analyze six samples for six different analytes, this same format has the potential to allow a single sample to be tested for 36 different agents. The method described herein demonstrates proof of principle that the number of analytes detectable using a single array can be increased simply by using complementary mixtures of capture and tracer antibodies. Mixtures were optimized to allow detection of closely related analytes without significant cross-reactivity. Following this facile modification of patterning and assay procedures, the following nine targets could be detected in a single 3 x 3 array: Staphylococcal enterotoxin B, ricin, cholera toxin, Bacillus anthracis Sterne, Bacillus globigii, Francisella tularensis LVS, Yersiniapestis F1 antigen, MS2 coliphage, and Salmonella typhimurium. This work maximizes the efficiency and utility of the described array technology, increasing only reagent usage and cost; production and fabrication costs are not affected.

  9. Probabilistic capture zone delineation based on an analytic solution.

    PubMed

    Jacobson, Elizabeth; Andricevic, Roko; Morrice, Joseph

    2002-01-01

    A major tool used in the design of wellhead protection areas is the delineation of a capture zone for a pumping well by use of a simple, steady-state analytic solution. This simple approach has been useful for many small municipalities because of the high costs associated with obtaining the hydrogeologic information needed for detailed numerical modeling. This analytic solution, however, is deterministic, and uncertainty in the mean value estimates of the hydraulic parameters used in this model can be a major source of error in predicting capture zones. To address this problem, a statistical theory was developed for including the uncertainty in the transmissivity and the magnitude and direction of the hydraulic head gradient in the analytic solution for both the ultimate and time-dependent capture zone for an arbitrary reliability level. To demonstrate the method and investigate the effect of varying magnitudes of uncertainty on time-dependent capture zones, the method is applied to three synthetic data sets based on data from the Borden Aquifer in Ontario, Canada. In general, the results show that uncertainty in the length of the time-dependent capture zone at a given reliability level is dependent on the uncertainty in the magnitude of the mean regional flow, which is equal to the transmissivity multiplied by the hydraulic head gradient; uncertainty in the maximum width of the capture zone is dependent primarily on the uncertainty in the mean direction of the regional flow.

  10. Nine-analyte detection using an array-based biosensor

    NASA Technical Reports Server (NTRS)

    Taitt, Chris Rowe; Anderson, George P.; Lingerfelt, Brian M.; Feldstein, s. Mark. J.; Ligler, Frances S.

    2002-01-01

    A fluorescence-based multianalyte immunosensor has been developed for simultaneous analysis of multiple samples. While the standard 6 x 6 format of the array sensor has been used to analyze six samples for six different analytes, this same format has the potential to allow a single sample to be tested for 36 different agents. The method described herein demonstrates proof of principle that the number of analytes detectable using a single array can be increased simply by using complementary mixtures of capture and tracer antibodies. Mixtures were optimized to allow detection of closely related analytes without significant cross-reactivity. Following this facile modification of patterning and assay procedures, the following nine targets could be detected in a single 3 x 3 array: Staphylococcal enterotoxin B, ricin, cholera toxin, Bacillus anthracis Sterne, Bacillus globigii, Francisella tularensis LVS, Yersiniapestis F1 antigen, MS2 coliphage, and Salmonella typhimurium. This work maximizes the efficiency and utility of the described array technology, increasing only reagent usage and cost; production and fabrication costs are not affected.

  11. Algal Biomass Analysis by Laser-Based Analytical Techniques—A Review

    PubMed Central

    Pořízka, Pavel; Prochazková, Petra; Prochazka, David; Sládková, Lucia; Novotný, Jan; Petrilak, Michal; Brada, Michal; Samek, Ota; Pilát, Zdeněk; Zemánek, Pavel; Adam, Vojtěch; Kizek, René; Novotný, Karel; Kaiser, Jozef

    2014-01-01

    Algal biomass that is represented mainly by commercially grown algal strains has recently found many potential applications in various fields of interest. Its utilization has been found advantageous in the fields of bioremediation, biofuel production and the food industry. This paper reviews recent developments in the analysis of algal biomass with the main focus on the Laser-Induced Breakdown Spectroscopy, Raman spectroscopy, and partly Laser-Ablation Inductively Coupled Plasma techniques. The advantages of the selected laser-based analytical techniques are revealed and their fields of use are discussed in detail. PMID:25251409

  12. Setting analytical performance specifications based on outcome studies - is it possible?

    PubMed

    Horvath, Andrea Rita; Bossuyt, Patrick M M; Sandberg, Sverre; John, Andrew St; Monaghan, Phillip J; Verhagen-Kamerbeek, Wilma D J; Lennartz, Lieselotte; Cobbaert, Christa M; Ebert, Christoph; Lord, Sarah J

    2015-05-01

    The 1st Strategic Conference of the European Federation of Clinical Chemistry and Laboratory Medicine proposed a simplified hierarchy for setting analytical performance specifications (APS). The top two levels of the 1999 Stockholm hierarchy, i.e., evaluation of the effect of analytical performance on clinical outcomes and clinical decisions have been proposed to be replaced by one outcome-based model. This model can be supported by: (1a) direct outcome studies; and (1b) indirect outcome studies investigating the impact of analytical performance of the test on clinical classifications or decisions and thereby on the probability of patient relevant clinical outcomes. This paper reviews the need for outcome-based specifications, the most relevant types of outcomes to be considered, and the challenges and limitations faced when setting outcome-based APS. The methods of Model 1a and b are discussed and examples are provided for how outcome data can be translated to APS using the linked evidence and simulation or decision analytic techniques. Outcome-based APS should primarily reflect the clinical needs of patients; should be tailored to the purpose, role and significance of the test in a well defined clinical pathway; and should be defined at a level that achieves net health benefit for patients at reasonable costs. Whilst it is acknowledged that direct evaluations are difficult and may not be possible for all measurands, all other forms of setting APS should be weighed against that standard, and regarded as approximations. Better definition of the relationship between the analytical performance of tests and health outcomes can be used to set analytical performance criteria that aim to improve the clinical and cost-effectiveness of laboratory tests.

  13. [Clinical Application of Analytical and Medical Instruments Mainly Using MS Techniques].

    PubMed

    Tanaka, Koichi

    2016-02-01

    Analytical instruments for clinical use are commonly required to confirm the compounds and forms related to diseases with the highest possible sensitivity, quantitative performance, and specificity and minimal invasiveness within a short time, easily, and at a low cost. Advancements of technical innovation for Mass Spectrometer (MS) have led to techniques that meet such requirements. Besides confirming known substances, other purposes and advantages of MS that are not fully known to the public are using MS as a tool to discover unknown phenomena and compounds. An example is clarifying the mechanisms of human diseases. The human body has approximately 100 thousand types of protein, and there may be more than several million types of protein and their metabolites. Most of them have yet to be discovered, and their discovery may give birth to new academic fields and lead to the clarification of diseases, development of new medicines, etc. For example, using the MS system developed under "Contribution to drug discovery and diagnosis by next generation of advanced mass spectrometry system," one of the 30 projects of the "Funding Program for World-Leading Innovative R&D on Science and Technology" (FIRST program), and other individual basic technologies, we succeeded in discovering new disease biomarker candidates for Alzheimer's disease, cancer, etc. Further contribution of MS to clinical medicine can be expected through the development and improvement of new techniques, efforts to verify discoveries, and communications with the medical front.

  14. Balloon-based interferometric techniques

    NASA Technical Reports Server (NTRS)

    Rees, David

    1985-01-01

    A balloon-borne triple-etalon Fabry-Perot Interferometer, observing the Doppler shifts of absorption lines caused by molecular oxygen and water vapor in the far red/near infrared spectrum of backscattered sunlight, has been used to evaluate a passive spaceborne remote sensing technique for measuring winds in the troposphere and stratosphere. There have been two successful high altitude balloon flights of the prototype UCL instrument from the National Scientific Balloon Facility at Palestine, TE (May 80, Oct. 83). The results from these flights have demonstrated that an interferometer with adequate resolution, stability and sensitivity can be built. The wind data are of comparable quality to those obtained from operational techniques (balloon and rocket sonde, cloud-top drift analysis, and from the gradient wind analysis of satellite radiance measurements). However, the interferometric data can provide a regular global grid, over a height range from 5 to 50 km in regions of clear air. Between the middle troposphere (5 km) and the upper stratosphere (40 to 50 km), an optimized instrument can make wind measurements over the daylit hemisphere with an accuracy of about 3 to 5 m/sec (2 sigma). It is possible to obtain full height profiles between altitudes of 5 and 50 km, with 4 km height resolution, and a spatial resolution of about 200 km, along the orbit track. Below an altitude of about 10 km, Fraunhofer lines of solar origin are possible targets of the Doppler wind analysis. Above an altitude of 50 km, the weakness of the backscattered solar spectrum (decreasing air density) is coupled with the low absorption crosssection of all atmospheric species in the spectral region up to 800 nm (where imaging photon detectors can be used), causing the along-the-track resolution (or error) to increase beyond values useful for operational purposes. Within the region of optimum performance (5 to 50 km), however, the technique is a valuable potential complement to existing wind

  15. Toner and paper-based fabrication techniques for microfluidic applications.

    PubMed

    Coltro, Wendell Karlos Tomazelli; de Jesus, Dosil Pereira; da Silva, José Alberto Fracassi; do Lago, Claudimir Lucio; Carrilho, Emanuel

    2010-08-01

    The interest in low-cost microfluidic platforms as well as emerging microfabrication techniques has increased considerably over the last years. Toner- and paper-based techniques have appeared as two of the most promising platforms for the production of disposable devices for on-chip applications. This review focuses on recent advances in the fabrication techniques and in the analytical/bioanalytical applications of toner and paper-based devices. The discussion is divided in two parts dealing with (i) toner and (ii) paper devices. Examples of miniaturized devices fabricated by using direct-printing or toner transfer masking in polyester-toner, glass, PDMS as well as conductive platforms as recordable compact disks and printed circuit board are presented. The construction and the use of paper-based devices for off-site diagnosis and bioassays are also described to cover this emerging platform for low-cost diagnostics.

  16. Disc-based microarrays: principles and analytical applications.

    PubMed

    Morais, Sergi; Puchades, Rosa; Maquieira, Ángel

    2016-07-01

    The idea of using disk drives to monitor molecular biorecognition events on regular optical discs has received considerable attention during the last decade. CDs, DVDs, Blu-ray discs and other new optical discs are universal and versatile supports with the potential for development of protein and DNA microarrays. Besides, standard disk drives incorporated in personal computers can be used as compact and affordable optical reading devices. Consequently, a CD technology, resulting from the audio-video industry, has been used to develop analytical applications in health care, environmental monitoring, food safety and quality assurance. The review presents and critically evaluates the current state of the art of disc-based microarrays with illustrative examples, including past, current and future developments. Special mention is made of the analytical developments that use either chemically activated or raw standard CDs where proteins, oligonucleotides, peptides, haptens or other biological probes are immobilized. The discs are also used to perform the assays and must maintain their readability with standard optical drives. The concept and principle of evolving disc-based microarrays and the evolution of disk drives as optical detectors are also described. The review concludes with the most relevant uses ordered chronologically to provide an overview of the progress of CD technology applications in the life sciences. Also, it provides a selection of important references to the current literature. Graphical Abstract High density disc-based microarrays.

  17. Analysis of hydroponic fertilizer matrixes for perchlorate: comparison of analytical techniques.

    PubMed

    Collette, Timothy W; Williams, Ted L; Urbansky, Edward T; Magnuson, Matthew L; Hebert, Gretchen N; Strauss, Steven H

    2003-01-01

    Seven retail hydroponic nitrate fertilizer products, two liquid and five solid, were comparatively analyzed for the perchlorate anion (ClO4-) by ion chromatography (IC) with suppressed conductivity detection, complexation electrospray ionization mass spectrometry (cESI-MS), normal Raman spectroscopy, and infrared spectroscopy using an attenuated total reflectance crystal (ATR-FTIR) coated with a thin film of an organometallic ion-exchange compound. Three of the five solid products were found by all techniques to contain perchlorate at the level of approximately 100-350 mg kg(-1). The remaining products did not contain perchlorate above the detection level of any of the techniques. Comparative analysis using several analytical techniques that depend on different properties of perchlorate allow for a high degree of certainty in both the qualitative and quantitative determinations. This proved particularly useful for these samples, due to the complexity of the matrix. Analyses of this type, including multiple spectroscopic confirmations, may also be useful for other complicated matrixes (e.g., biological samples) or in forensic/regulatory frameworks where data are likely to be challenged. While the source of perchlorate in these hydroponic products is not known, the perchlorate-to-nitrate concentration ratio (w/w) in the aqueous extracts is generally consistent with the historical weight percent of water soluble components in caliche, a nitrate-bearing ore found predominantly in Chile. This ore, which is the only well-established natural source of perchlorate, is mined and used, albeit minimally, as a nitrogen source in some fertilizer products.

  18. Employing socially driven techniques for framing, contextualization, and collaboration in complex analytical threads

    NASA Astrophysics Data System (ADS)

    Wollocko, Arthur; Danczyk, Jennifer; Farry, Michael; Jenkins, Michael; Voshell, Martin

    2015-05-01

    The proliferation of sensor technologies continues to impact Intelligence Analysis (IA) work domains. Historical procurement focus on sensor platform development and acquisition has resulted in increasingly advanced collection systems; however, such systems often demonstrate classic data overload conditions by placing increased burdens on already overtaxed human operators and analysts. Support technologies and improved interfaces have begun to emerge to ease that burden, but these often focus on single modalities or sensor platforms rather than underlying operator and analyst support needs, resulting in systems that do not adequately leverage their natural human attentional competencies, unique skills, and training. One particular reason why emerging support tools often fail is due to the gap between military applications and their functions, and the functions and capabilities afforded by cutting edge technology employed daily by modern knowledge workers who are increasingly "digitally native." With the entry of Generation Y into these workplaces, "net generation" analysts, who are familiar with socially driven platforms that excel at giving users insight into large data sets while keeping cognitive burdens at a minimum, are creating opportunities for enhanced workflows. By using these ubiquitous platforms, net generation analysts have trained skills in discovering new information socially, tracking trends among affinity groups, and disseminating information. However, these functions are currently under-supported by existing tools. In this paper, we describe how socially driven techniques can be contextualized to frame complex analytical threads throughout the IA process. This paper focuses specifically on collaborative support technology development efforts for a team of operators and analysts. Our work focuses on under-supported functions in current working environments, and identifies opportunities to improve a team's ability to discover new information and

  19. Analytical techniques for sesquiterpene emission rate studies in vegetation enclosure experiments

    NASA Astrophysics Data System (ADS)

    Helmig, Detlev; Bocquet, Florence; Pollmann, Jan; Revermann, Tobias

    Sesquiterpene (SQT) compounds (C 15H 24) and their oxygenated alcohol and ketone derivatives are biogenic volatile organic compounds that have been identified in emissions from vegetation. SQT emission rates and landscape flux estimates are highly uncertain. Reliable ambient flux measurements have not been possible because of low-ambient concentrations, rapid atmospheric reactions (prohibiting ambient tower flux measurements), and analytical challenges and uncertainties that stem from the low volatility of SQT. Standards from an in situ capillary diffusion system with 18 SQT compounds and four other organic compounds (geranylacetone, 1,3,5-tri-isopropylbenzene, diphenylmethane, nonylbenzene) were used to thoroughly investigate experimental procedures for SQT emission rate studies by vegetation enclosure techniques. Recovery rates in tubing materials, sampling bags, leaf cuvettes, on six solid adsorbent materials (Tenax TA, Tenax GR, Carbotrap, Carbotrap C, Unibeads, Glass Beads) for gas chromatography analysis, and gas chromatography retention indices and mass spectral fragmentation patterns were determined. SQT compounds were found to exhibit a high degree of stickiness to all materials tested. However, the non-oxygenated SQT can be recovered in enclosure experiments for quantitative emission rate determination after careful consideration of the analytical conditions. It is utmost important to allow sufficient purging and equilibration times for all materials in contact with the sample air. In contrast oxygenated SQT were irreversibly lost in enclosure experiments which made their quantitative measurement prohibitive. Results for the other organic compounds were similar and indicate that these data mostly stem from the volatility of these compounds. Consequently, the findings of this study provide guidelines for the analysis of a wide range of volatile organic compounds in the ˜C13-C17 volatility range.

  20. Analytic calculation of physiological acid-base parameters in plasma.

    PubMed

    Wooten, E W

    1999-01-01

    Analytic expressions for plasma total titratable base, base excess (DeltaCB), strong-ion difference, change in strong-ion difference (DeltaSID), change in Van Slyke standard bicarbonate (DeltaVSSB), anion gap, and change in anion gap are derived as a function of pH, total buffer ion concentration, and conditional molar equilibrium constants. The behavior of these various parameters under respiratory and metabolic acid-base disturbances for constant and variable buffer ion concentrations is considered. For constant noncarbonate buffer concentrations, DeltaSID = DeltaCB = DeltaVSSB, whereas these equalities no longer hold under changes in noncarbonate buffer concentration. The equivalence is restored if the reference state is changed to include the new buffer concentrations.

  1. An analytic function approach to weak mutually unbiased bases

    NASA Astrophysics Data System (ADS)

    Olupitan, T.; Lei, C.; Vourdas, A.

    2016-08-01

    Quantum systems with variables in Z(d) are considered, and three different structures are studied. The first is weak mutually unbiased bases, for which the absolute value of the overlap of any two vectors in two different bases is 1 /√{ k } (where k | d) or 0. The second is maximal lines through the origin in the Z(d) × Z(d) phase space. The third is an analytic representation in the complex plane based on Theta functions, and their zeros. It is shown that there is a correspondence (triality) that links strongly these three apparently different structures. For simplicity, the case where d =p1 ×p2, where p1 ,p2 are odd prime numbers different from each other, is considered.

  2. Multidimensional metrics of niche space for use with diverse analytical techniques

    PubMed Central

    Bowes, Rachel E.; Thorp, James H.; Reuman, Daniel C.

    2017-01-01

    Multidimensional data are integral to many community-ecological studies and come in various forms, such as stable isotopes, compound specific analyses (e.g., amino acids and fatty acids), and both biodiversity and life history traits. Scientists employing such data often lack standardized metrics to evaluate communities in niche space where more than 2 dimensions are involved. To alleviate this problem, we developed a graphing and analytical approach for use with more than two variables, based on previously established stable isotope bi-plot metrics. We introduce here our community metrics as R scripts. By extending the original metrics to multiple dimensions, we created n-dimensional plots and metrics to characterize any set of quantitative measurements of a community. We demonstrate the utility of these metrics using stable isotope data; however, the approaches are applicable to many types of data. The resulting metrics provide more and better information compared to traditional analytic frameworks. The approach can be applied in many branches of community ecology, and it offers accessible metrics to quantitatively analyze the structure of communities across ecosystems and through time. PMID:28145524

  3. Development of analytical techniques for ultra trace amounts of nuclear materials in environmental samples using ICP-MS for safeguards

    PubMed

    Magara; Hanzawa; Esaka; Miyamoto; Yasuda; Watanabe; Usuda; Nishimura; Adachi

    2000-07-01

    The authors have begun to develop analytical techniques for ultra trace amounts of nuclear materials and to prepare a clean chemistry laboratory for environmental sample analyses. The analytical techniques include bulk and particle analyses. For the bulk analysis, concentrations and isotopic ratios of U and/or Pu are determined by inductively-coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS). In the particle analysis, isotopic ratios of U and/or Pu in each particle will be measured by secondary ion mass spectrometry (SIMS). This paper reports on the outline for the development of analytical techniques and the current situation of the development of the bulk analysis using ICP-MS is described.

  4. Physics-based analytical model for ferromagnetic single electron transistor

    NASA Astrophysics Data System (ADS)

    Jamshidnezhad, K.; Sharifi, M. J.

    2017-03-01

    A physically based compact analytical model is proposed for a ferromagnetic single electron transistor (FSET). This model is based on the orthodox theory and solves the master equation, spin conservation equation, and charge neutrality equation simultaneously. The model can be applied to both symmetric and asymmetric devices and does not introduce any limitation on the applied bias voltages. This feature makes the model suitable for both analog and digital applications. To verify the accuracy of the model, its results regarding a typical FSET in both low and high voltage regimes are compared with the existing numerical results. Moreover, the model's results of a parallel configuration FSET, where no spin accumulation exists in the island, are compared with the results obtained from a Monte Carlo simulation using SIMON. These two comparisons show that our model is valid and accurate. As another comparison, the model is compared analytically with an existing model for a double barrier ferromagnetic junction (having no gate). This also verifies the accuracy of the model.

  5. Analytical phase-tracking-based strain estimation for ultrasound elasticity.

    PubMed

    Yuan, Lili; Pedersen, Peder C

    2015-01-01

    A new strain estimator for quasi-static elastography is presented, based on tracking of the analytical signal phase as a function of the external force. Two implementations are introduced: zero-phase search with moving window (SMW) and zero-phase band tracking using connected component labeling (CCL). Low analytical signal amplitude caused by local destructive interference is associated with large error in the phase trajectories, and amplitude thresholding can thus be used to terminate the phase tracking along a particular path. Interpolation is then applied to estimate displacement in the eliminated path. The paper describes first a mathematical analysis based on 1-D multi-scatter modeling, followed by a statistical study of the displacement and strain error. Simulation and experiment with an inhomogeneous phantom indicate that SMW and CCL are capable of reliably estimating tissue displacement and strain over a larger range of deformation than standard timedomain cross-correlation (SCC). Results also show that SMW is roughly 40 times faster than SCC with comparable or even better accuracy. CCL is slower than SMW, but more noise robust. Simulation assessment at compression level 3% and 6% with SNR 20 dB demonstrates average strain error for SMW and CCL of 10%, whereas SCC achieves 18%.

  6. Multiplexed Paper Analytical Device for Quantification of Metals using Distance-Based Detection

    PubMed Central

    Cate, David M.; Noblitt, Scott D.; Volckens, John; Henry, Charles S.

    2015-01-01

    Exposure to metal-containing aerosols has been linked with adverse health outcomes for almost every organ in the human body. Commercially available techniques for quantifying particulate metals are time-intensive, laborious, and expensive; often sample analysis exceeds $100. We report a simple technique, based upon a distance-based detection motif, for quantifying metal concentrations of Ni, Cu, and Fe in airborne particulate matter using microfluidic paper-based analytical devices. Paper substrates are used to create sensors that are self-contained, self-timing, and require only a drop of sample for operation. Unlike other colorimetric approaches in paper microfluidics that rely on optical instrumentation for analysis, with distance-based detection, analyte is quantified visually based on the distance of a colorimetric reaction, similar to reading temperature on a thermometer. To demonstrate the effectiveness of this approach, Ni, Cu, and Fe were measured individually in single-channel devices; detection limits as low as 0.1, 0.1, and 0.05 µg were reported for Ni, Cu, and Fe. Multiplexed analysis of all three metals was achieved with detection limits of 1, 5, and 1 µg for Ni, Cu, and Fe. We also extended the dynamic range for multi-analyte detection by printing concentration gradients of colorimetric reagents using an off the shelf inkjet printer. Analyte selectivity was demonstrated for common interferences. To demonstrate utility of the method, Ni, Cu, and Fe were measured from samples of certified welding fume; levels measured with paper sensors matched known values determined gravimetrically. PMID:26009988

  7. Multiplexed paper analytical device for quantification of metals using distance-based detection.

    PubMed

    Cate, David M; Noblitt, Scott D; Volckens, John; Henry, Charles S

    2015-07-07

    Exposure to metal-containing aerosols has been linked with adverse health outcomes for almost every organ in the human body. Commercially available techniques for quantifying particulate metals are time-intensive, laborious, and expensive; often sample analysis exceeds $100. We report a simple technique, based upon a distance-based detection motif, for quantifying metal concentrations of Ni, Cu, and Fe in airborne particulate matter using microfluidic paper-based analytical devices. Paper substrates are used to create sensors that are self-contained, self-timing, and require only a drop of sample for operation. Unlike other colorimetric approaches in paper microfluidics that rely on optical instrumentation for analysis, with distance-based detection, analyte is quantified visually based on the distance of a colorimetric reaction, similar to reading temperature on a thermometer. To demonstrate the effectiveness of this approach, Ni, Cu, and Fe were measured individually in single-channel devices; detection limits as low as 0.1, 0.1, and 0.05 μg were reported for Ni, Cu, and Fe. Multiplexed analysis of all three metals was achieved with detection limits of 1, 5, and 1 μg for Ni, Cu, and Fe. We also extended the dynamic range for multi-analyte detection by printing concentration gradients of colorimetric reagents using an off-the-shelf inkjet printer. Analyte selectivity was demonstrated for common interferences. To demonstrate utility of the method, Ni, Cu, and Fe were measured from samples of certified welding fume; levels measured with paper sensors matched known values determined gravimetrically.

  8. Evaluation of a wind-tunnel gust response technique including correlations with analytical and flight test results

    NASA Technical Reports Server (NTRS)

    Redd, L. T.; Hanson, P. W.; Wynne, E. C.

    1979-01-01

    A wind tunnel technique for obtaining gust frequency response functions for use in predicting the response of flexible aircraft to atmospheric turbulence is evaluated. The tunnel test results for a dynamically scaled cable supported aeroelastic model are compared with analytical and flight data. The wind tunnel technique, which employs oscillating vanes in the tunnel throat section to generate a sinusoidally varying flow field around the model, was evaluated by use of a 1/30 scale model of the B-52E airplane. Correlation between the wind tunnel results, flight test results, and analytical predictions for response in the short period and wing first elastic modes of motion are presented.

  9. Recent developments in computer vision-based analytical chemistry: A tutorial review.

    PubMed

    Capitán-Vallvey, Luis Fermín; López-Ruiz, Nuria; Martínez-Olmos, Antonio; Erenas, Miguel M; Palma, Alberto J

    2015-10-29

    Chemical analysis based on colour changes recorded with imaging devices is gaining increasing interest. This is due to its several significant advantages, such as simplicity of use, and the fact that it is easily combinable with portable and widely distributed imaging devices, resulting in friendly analytical procedures in many areas that demand out-of-lab applications for in situ and real-time monitoring. This tutorial review covers computer vision-based analytical (CVAC) procedures and systems from 2005 to 2015, a period of time when 87.5% of the papers on this topic were published. The background regarding colour spaces and recent analytical system architectures of interest in analytical chemistry is presented in the form of a tutorial. Moreover, issues regarding images, such as the influence of illuminants, and the most relevant techniques for processing and analysing digital images are addressed. Some of the most relevant applications are then detailed, highlighting their main characteristics. Finally, our opinion about future perspectives is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Dynamic fragmentation of brittle materials: analytical mechanics-based models

    NASA Astrophysics Data System (ADS)

    Drugan, W. J.

    2001-06-01

    Two analytical mechanics-based models of dynamic fragmentation in brittle materials are proposed and solved to predict fragment size and time to fragmentation onset in terms of fundamental material properties and the applied strain rate. Previous widely adopted analytical models of dynamic fragmentation are based on relatively simple energy balance arguments, and assume that the fragmentation event occurs instantaneously. The present models account for the actual time-varying dynamic deformation that occurs prior to fragmentation onset. One of the models treats the fragmenting material as initially flaw-free, and determines the minimum fragment size predicted by a dynamic instability analysis. The second model accounts for initial flaw spacing (which may correlate physically with, for example, grain size), and a dynamic instability analysis is employed to determine which flaws become critical. The fragment size predictions of the present models and two previous energy-based models are found to agree at extremely high strain rates (≈5×10 7/s for dense alumina), but the present, more realistic analysis indicates that the regime of validity of the energy-based models is rather restricted. The predictions of the present models are also shown to agree with those of a recent numerical finite element simulation of dynamic fragmentation which applies to a lower strain rate regime. Comparisons of the two new models show that if a material contains initial flaws whose spacing is smaller than the predicted fragment size of an equivalent "unflawed" material, the fragment size of the preflawed material will be smaller in general, but usually not as small as the initial flaw spacing. The analysis also permits determination of the evolution of the strain rate distribution in a prospective fragment before and after fragmentation initiation; results are presented for some example cases. Finally, closed-form analytical results are derived for minimum fragment size and time to

  11. Chemical and mineralogical characterizations of LD converter steel slags: A multi-analytical techniques approach

    SciTech Connect

    Waligora, J.; Bulteel, D.; Degrugilliers, P.; Damidot, D.; Potdevin, J.L.; Measson, M.

    2010-01-15

    The use of LD converter steel slags (coming from Linz-Donawitz steelmaking process) as aggregates in road construction can in certain cases lead to dimensional damage due to a macroscopic swelling that is the consequence of chemical reactions. The aim of this study was to couple several analytical techniques in order to carefully undertake chemical and mineralogical characterizations of LD steel slags and identify the phases that are expected to be responsible for their instability. Optical microscopy, scanning electron microscopy and electron probe microanalyses revealed that LD steel slags mainly contain calcium silicates, dicalcium ferrites, iron oxides and lime. However, as a calcium silicate phase is heterogeneous, Raman microspectrometry and transmitted electron microscopy had to be used to characterize it more precisely. Results showed that lime is present under two forms in slag grains: some nodules observed in the matrix whose size ranges from 20 to 100 {mu}m and some micro-inclusions, enclosed in the heterogeneous calcium silicate phase whose size ranges from 1 to 3 {mu}m. It was also established that without the presence of magnesia, lime is expected to be the only phase responsible for LD steel slags instability. Nevertheless, the distribution of lime between nodules and micro-inclusions may play a major role and could explain that similar amounts of lime can induce different instabilities. Thus, it appears that lime content of LD steel slags is not the only parameter to explain their instability.

  12. Development of rocket electrophoresis technique as an analytical tool in preformulation study of tetanus vaccine formulation.

    PubMed

    Ahire, V J; Sawant, K K

    2006-08-01

    Rocket Electrophoresis (RE) technique relies on the difference in charges of the antigen and antibodies at the selected pH. The present study involves optimization of RE run conditions for Tetanus Toxoid (TT). Agarose gel (1% w/v, 20 ml, pH 8.6), anti-TT IgG - 1 IU/ml, temperature 4-8 degrees C and run duration of 18 h was found to be optimum. Height of the rocket-shaped precipitate was proportional to TT concentration. The RE method was found to be linear in the concentration range of 2.5 to 30 Lf/mL. The method was validated and found to be accurate, precise, and reproducible when analyzed statistically using student's t-test. RE was used as an analytical method for analyzing TT content in plain and marketed formulations as well as for the preformulation study of vaccine formulation where formulation additives were tested for compatibility with TT. The optimized RE method has several advantages: it uses safe materials, is inexpensive, and easy to perform. RE results are less prone to operator's bias as compared to flocculation test and can be documented by taking photographs and scanned by densitometer; RE can be easily standardized for the required antigen concentration by changing antitoxin concentration. It can be used as a very effective tool for qualitative and quantitative analysis and in preformulation studies of antigens.

  13. Processing of calamine with modern analytical techniques: Processed with Huanglian Decoction () and Sanhuang Decoction ().

    PubMed

    Meng, Xiang-Long; Ma, Jun-Nan; Guo, Xiao-Hui; Liu, Bing-Chen; Cui, Nan-Nan; Li, Kun; Zhang, Shuo-Sheng

    2017-07-28

    To determine the pyrolysis characteristics of calcined and processed calamine, qualitatively and quantitatively compare the contents of related elements, morphology and functional groups of the pyrolysis products dried at different heating temperatures and explore the critical temperature and the optimal drying temperature for the process of calamine with Huanglian Decoction (HLD, ) and San Huang Decoction (SHD, ). Pyrolysis products were prepared by programmable and constantly heating the calcined and processed calamine to or at different heating temperatures. Thermogravimetry (TG) was used to test their pyrolysis characteristics. Fourier transform infrared spectroscopy and scanning electron microscopeenergy dispersive spectrometer were used to determine their morphology, functional groups and element contents. Page model was used to investigate the constant drying kinetics of processed calamine. The adding of HLD or SHD to calcined calamine (CC) can slow its weight loss in drying pyrolysis process. The temperature ranges where HLD and SHD can affect its weight loss were 65-150 °C and 74-180 °C, respectively. The drying temperature was optimized as 90 °C. The drying kinetic for the processed calamine fits Page model shows good linearity. The critical temperature and the optimal drying temperature where HLD and SHD can affect the weight loss rate in the process of calamine were explored using the theories and methods of both biophysical chemistry and processing of Chinese materia medica. This work provides a good example for the study of the process of other Chinese medicines using modern analytical techniques.

  14. Discrimination between biologically relevant calcium phosphate phases by surface-analytical techniques

    NASA Astrophysics Data System (ADS)

    Kleine-Boymann, Matthias; Rohnke, Marcus; Henss, Anja; Peppler, Klaus; Sann, Joachim; Janek, Juergen

    2014-08-01

    The spatially resolved phase identification of biologically relevant calcium phosphate phases (CPPs) in bone tissue is essential for the elucidation of bone remodeling mechanisms and for the diagnosis of bone diseases. Analytical methods with high spatial resolution for the discrimination between chemically quite close phases are rare. Therefore the applicability of state-of-the-art ToF-SIMS, XPS and EDX as chemically specific techniques was investigated. The eight CPPs hydroxyapatite (HAP), β-tricalcium phosphate (β-TCP), α-tricalcium phosphate (α-TCP), octacalcium phosphate (OCP), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate (DCP), monocalcium phosphate (MCP) and amorphous calcium phosphate (ACP) were either commercial materials in high purity or synthesized by ourselves. The phase purity was proven by XRD analysis. All of the eight CPPs show different mass spectra and the phases can be discriminated by applying the principal component analysis method to the mass spectrometric data. The Ca/P ratios of all phosphates were determined by XPS and EDX. With both methods some CPPs can be distinguished, but the obtained Ca/P ratios deviate systematically from their theoretical values. It is necessary in any case to determine a calibration curve, respectively the ZAF values, from appropriate standards. In XPS also the O(1s)-satellite signals are correlated to the CPPs composition. Angle resolved and long-term XPS measurements of HAP clearly prove that there is no phosphate excess at the surface. Decomposition due to X-ray irradiation has not been observed.

  15. Evaluation of Various Hybrid Analytical Techniques for Resolving Arsenic Species in Soils and Natural Waters from Korea

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Yoon, H.; Shin, M.; Yoon, C.; Woo, N.

    2005-12-01

    The importance of arsenic detection in terms of different chemical species is becoming nowadays environmental concern. The analytical technique for true separation of different arsenic species has been challenging in many environmental samples. Achieving correct analytical results and resolving the lowest detection limit of each species is also desirable. However arsenic species can be transformed rapidly by slight changes in redox condition during experimental manipulation. It has been documented by USEPA for standard analytical technique for arsenic from many samples. However the previously documented techniques concerns only total arsenic concentration. Many analytical techniques for analyzing arsenic species are being suggested and hybrid analytical technique is regarded as essential method to resolve arsenic species. In this study, various hybrid techniques using ICP were tested to separate arsenic species in different type of samples. The anion exchange cartridge (Accell Plus QMA, Waters) or column (PRP X-100, Hamilton) in the part for separation and (HG)-ICP-AES or (HG)-ICP-MS in the part for detection coupled. Hydride generation (HG) method is used to improve detection limits. In addition, it can prevent from interference of 75 ArCl which is a significant problem of ICP-MS application to arsenic analysis. Anion exchange cartridge is only applicable in separation of inorganic arsenic species, typically available to acid mine drainage and groundwater samples in which arsenic mainly exists inorganic form. LC-(HG)-ICP-MS techenique is profitable to natural surface water samples which have a small fraction of various arsenic species. The leachate from soil samples should be treated carefully because high content of transition metals cause interferences. If there were a probability of leaching considerable amount of organic matter and transition metals during soil extraction, HG technique with purification procedure and use of masking agent must be applied to

  16. Analytical modeling of glucose biosensors based on carbon nanotubes

    PubMed Central

    2014-01-01

    In recent years, carbon nanotubes have received widespread attention as promising carbon-based nanoelectronic devices. Due to their exceptional physical, chemical, and electrical properties, namely a high surface-to-volume ratio, their enhanced electron transfer properties, and their high thermal conductivity, carbon nanotubes can be used effectively as electrochemical sensors. The integration of carbon nanotubes with a functional group provides a good and solid support for the immobilization of enzymes. The determination of glucose levels using biosensors, particularly in the medical diagnostics and food industries, is gaining mass appeal. Glucose biosensors detect the glucose molecule by catalyzing glucose to gluconic acid and hydrogen peroxide in the presence of oxygen. This action provides high accuracy and a quick detection rate. In this paper, a single-wall carbon nanotube field-effect transistor biosensor for glucose detection is analytically modeled. In the proposed model, the glucose concentration is presented as a function of gate voltage. Subsequently, the proposed model is compared with existing experimental data. A good consensus between the model and the experimental data is reported. The simulated data demonstrate that the analytical model can be employed with an electrochemical glucose sensor to predict the behavior of the sensing mechanism in biosensors. PMID:24428818

  17. Standardization of chemical analytical techniques for pyrolysis bio-oil: history, challenges, and current status of methods

    DOE PAGES

    Ferrell, Jack R.; Olarte, Mariefel V.; Christensen, Earl D.; ...

    2016-07-05

    Here, we discuss the standardization of analytical techniques for pyrolysis bio-oils, including the current status of methods, and our opinions on future directions. First, the history of past standardization efforts is summarized, and both successful and unsuccessful validation of analytical techniques highlighted. The majority of analytical standardization studies to-date has tested only physical characterization techniques. In this paper, we present results from an international round robin on the validation of chemical characterization techniques for bio-oils. Techniques tested included acid number, carbonyl titrations using two different methods (one at room temperature and one at 80 °C), 31P NMR for determination ofmore » hydroxyl groups, and a quantitative gas chromatography–mass spectrometry (GC-MS) method. Both carbonyl titration and acid number methods have yielded acceptable inter-laboratory variabilities. 31P NMR produced acceptable results for aliphatic and phenolic hydroxyl groups, but not for carboxylic hydroxyl groups. As shown in previous round robins, GC-MS results were more variable. Reliable chemical characterization of bio-oils will enable upgrading research and allow for detailed comparisons of bio-oils produced at different facilities. Reliable analytics are also needed to enable an emerging bioenergy industry, as processing facilities often have different analytical needs and capabilities than research facilities. We feel that correlations in reliable characterizations of bio-oils will help strike a balance between research and industry, and will ultimately help to -determine metrics for bio-oil quality. Lastly, the standardization of additional analytical methods is needed, particularly for upgraded bio-oils.« less

  18. Standardization of chemical analytical techniques for pyrolysis bio-oil: history, challenges, and current status of methods

    SciTech Connect

    Ferrell, Jack R.; Olarte, Mariefel V.; Christensen, Earl D.; Padmaperuma, Asanga B.; Connatser, Raynella M.; Stankovikj, Filip; Meier, Dietrich; Paasikallio, Ville

    2016-07-05

    Here, we discuss the standardization of analytical techniques for pyrolysis bio-oils, including the current status of methods, and our opinions on future directions. First, the history of past standardization efforts is summarized, and both successful and unsuccessful validation of analytical techniques highlighted. The majority of analytical standardization studies to-date has tested only physical characterization techniques. In this paper, we present results from an international round robin on the validation of chemical characterization techniques for bio-oils. Techniques tested included acid number, carbonyl titrations using two different methods (one at room temperature and one at 80 °C), 31P NMR for determination of hydroxyl groups, and a quantitative gas chromatography–mass spectrometry (GC-MS) method. Both carbonyl titration and acid number methods have yielded acceptable inter-laboratory variabilities. 31P NMR produced acceptable results for aliphatic and phenolic hydroxyl groups, but not for carboxylic hydroxyl groups. As shown in previous round robins, GC-MS results were more variable. Reliable chemical characterization of bio-oils will enable upgrading research and allow for detailed comparisons of bio-oils produced at different facilities. Reliable analytics are also needed to enable an emerging bioenergy industry, as processing facilities often have different analytical needs and capabilities than research facilities. We feel that correlations in reliable characterizations of bio-oils will help strike a balance between research and industry, and will ultimately help to -determine metrics for bio-oil quality. Lastly, the standardization of additional analytical methods is needed, particularly for upgraded bio-oils.

  19. Standardization of chemical analytical techniques for pyrolysis bio-oil: history, challenges, and current status of methods

    SciTech Connect

    Ferrell, Jack R.; Olarte, Mariefel V.; Christensen, Earl D.; Padmaperuma, Asanga B.; Connatser, Raynella M.; Stankovikj, Filip; Meier, Dietrich; Paasikallio, Ville

    2016-07-05

    Here, we discuss the standardization of analytical techniques for pyrolysis bio-oils, including the current status of methods, and our opinions on future directions. First, the history of past standardization efforts is summarized, and both successful and unsuccessful validation of analytical techniques highlighted. The majority of analytical standardization studies to-date has tested only physical characterization techniques. In this paper, we present results from an international round robin on the validation of chemical characterization techniques for bio-oils. Techniques tested included acid number, carbonyl titrations using two different methods (one at room temperature and one at 80 °C), 31P NMR for determination of hydroxyl groups, and a quantitative gas chromatography–mass spectrometry (GC-MS) method. Both carbonyl titration and acid number methods have yielded acceptable inter-laboratory variabilities. 31P NMR produced acceptable results for aliphatic and phenolic hydroxyl groups, but not for carboxylic hydroxyl groups. As shown in previous round robins, GC-MS results were more variable. Reliable chemical characterization of bio-oils will enable upgrading research and allow for detailed comparisons of bio-oils produced at different facilities. Reliable analytics are also needed to enable an emerging bioenergy industry, as processing facilities often have different analytical needs and capabilities than research facilities. We feel that correlations in reliable characterizations of bio-oils will help strike a balance between research and industry, and will ultimately help to -determine metrics for bio-oil quality. Lastly, the standardization of additional analytical methods is needed, particularly for upgraded bio-oils.

  20. Novel concept of washing for microfluidic paper-based analytical devices based on capillary force of paper substrates.

    PubMed

    Mohammadi, Saeed; Busa, Lori Shayne Alamo; Maeki, Masatoshi; Mohamadi, Reza M; Ishida, Akihiko; Tani, Hirofumi; Tokeshi, Manabu

    2016-11-01

    A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported. Liquids can flow through a porous medium (such as paper) in the absence of external pressure as a result of capillary action. Uniform results were achieved when washing a paper substrate in a PDMS holder which was integrated with a cartridge absorber acting as a porous medium. Our study demonstrated that applying this washing technique would allow μPADs to become the least expensive microfluidic device platform with high reproducibility and sensitivity. In a model μPAD assay that utilized this novel washing technique, C-reactive protein (CRP) was detected with a limit of detection (LOD) of 5 μg mL(-1). Graphical Abstract A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported.

  1. Assessing the Value of Structured Analytic Techniques in the U.S. Intelligence Community

    DTIC Science & Technology

    2016-01-01

    aim to make the analytic process conscious and transparent, thus reducing the probability of errors caused by numerous cognitive biases that go...SUMMARY ■ The Intelligence Community (IC) is strongly emphasizing the use of structured analytic tech- niques (SATs) to promote rigorous analysis...the attainment of IC analytic quality standards, and which specific SATs are most effective. RAND’s preliminary SAT review of a limited sample of

  2. Validation of SERT 2 thermal analytical techniques by thermal vacuum testing of the prototype satellite

    NASA Technical Reports Server (NTRS)

    Smolak, G. R.; Stevens, N. J.

    1971-01-01

    The thermal protection system for the flight configuration of the SERT 2 satellite was designed using an analytical thermal network to represent the satellite and its environment. A large part of this digital analytical network was adjusted and calibrated by comparing predicted temperatures with experimental measurements made with the prototype SERT 2 satellite in an extended thermal vacuum test. The procedures used in adjusting and calibrating the analytical network are outlined.

  3. Markov-CA model using analytical hierarchy process and multiregression technique

    NASA Astrophysics Data System (ADS)

    Omar, N. Q.; Sanusi, S. A. M.; Hussin, W. M. W.; Samat, N.; Mohammed, K. S.

    2014-06-01

    The unprecedented increase in population and rapid rate of urbanisation has led to extensive land use changes. Cellular automata (CA) are increasingly used to simulate a variety of urban dynamics. This paper introduces a new CA based on an integration model built-in multi regression and multi-criteria evaluation to improve the representation of CA transition rule. This multi-criteria evaluation is implemented by utilising data relating to the environmental and socioeconomic factors in the study area in order to produce suitability maps (SMs) using an analytical hierarchical process, which is a well-known method. Before being integrated to generate suitability maps for the periods from 1984 to 2010 based on the different decision makings, which have become conditioned for the next step of CA generation. The suitability maps are compared in order to find the best maps based on the values of the root equation (R2). This comparison can help the stakeholders make better decisions. Thus, the resultant suitability map derives a predefined transition rule for the last step for CA model. The approach used in this study highlights a mechanism for monitoring and evaluating land-use and land-cover changes in Kirkuk city, Iraq owing changes in the structures of governments, wars, and an economic blockade over the past decades. The present study asserts the high applicability and flexibility of Markov-CA model. The results have shown that the model and its interrelated concepts are performing rather well.

  4. Assessing the service quality of Iran military hospitals: Joint Commission International standards and Analytic Hierarchy Process (AHP) technique

    PubMed Central

    Bahadori, Mohammadkarim; Ravangard, Ramin; Yaghoubi, Maryam; Alimohammadzadeh, Khalil

    2014-01-01

    Background: Military hospitals are responsible for preserving, restoring and improving the health of not only armed forces, but also other people. According to the military organizations strategy, which is being a leader and pioneer in all areas, providing quality health services is one of the main goals of the military health care organizations. This study was aimed to evaluate the service quality of selected military hospitals in Iran based on the Joint Commission International (JCI) standards and comparing these hospitals with each other and ranking them using the analytic hierarchy process (AHP) technique in 2013. Materials and Methods: This was a cross-sectional and descriptive study conducted on five military hospitals, selected using the purposive sampling method, in 2013. Required data collected using checklists of accreditation standards and nominal group technique. AHP technique was used for prioritizing. Furthermore, Expert Choice 11.0 was used to analyze the collected data. Results: Among JCI standards, the standards of access to care and continuity of care (weight = 0.122), quality improvement and patient safety (weight = 0.121) and leadership and management (weight = 0.117) had the greatest importance, respectively. Furthermore, in the overall ranking, BGT (weight = 0.369), IHM (0.238), SAU (0.202), IHK (weight = 0.125) and SAB (weight = 0.066) ranked first to fifth, respectively. Conclusion: AHP is an appropriate technique for measuring the overall performance of hospitals and their quality of services. It is a holistic approach that takes all hospital processes into consideration. The results of the present study can be used to improve hospitals performance through identifying areas, which are in need of focus for quality improvement and selecting strategies to improve service quality. PMID:25250364

  5. Techniques for Enhancing Web-Based Education.

    ERIC Educational Resources Information Center

    Barbieri, Kathy; Mehringer, Susan

    The Virtual Workshop is a World Wide Web-based set of modules on high performance computing developed at the Cornell Theory Center (CTC) (New York). This approach reaches a large audience, leverages staff effort, and poses challenges for developing interesting presentation techniques. This paper describes the following techniques with their…

  6. Functionality of empirical model-based predictive analytics for the early detection of hemodynamic instabilty.

    PubMed

    Summers, Richard L; Pipke, Matt; Wegerich, Stephan; Conkright, Gary; Isom, Kristen C

    2014-01-01

    Background. Monitoring cardiovascular hemodynamics in the modern clinical setting is a major challenge. Increasing amounts of physiologic data must be analyzed and interpreted in the context of the individual patient’s pathology and inherent biologic variability. Certain data-driven analytical methods are currently being explored for smart monitoring of data streams from patients as a first tier automated detection system for clinical deterioration. As a prelude to human clinical trials, an empirical multivariate machine learning method called Similarity-Based Modeling (“SBM”), was tested in an In Silico experiment using data generated with the aid of a detailed computer simulator of human physiology (Quantitative Circulatory Physiology or “QCP”) which contains complex control systems with realistic integrated feedback loops. Methods. SBM is a kernel-based, multivariate machine learning method that that uses monitored clinical information to generate an empirical model of a patient’s physiologic state. This platform allows for the use of predictive analytic techniques to identify early changes in a patient’s condition that are indicative of a state of deterioration or instability. The integrity of the technique was tested through an In Silico experiment using QCP in which the output of computer simulations of a slowly evolving cardiac tamponade resulted in progressive state of cardiovascular decompensation. Simulator outputs for the variables under consideration were generated at a 2-min data rate (0.083Hz) with the tamponade introduced at a point 420 minutes into the simulation sequence. The functionality of the SBM predictive analytics methodology to identify clinical deterioration was compared to the thresholds used by conventional monitoring methods. Results. The SBM modeling method was found to closely track the normal physiologic variation as simulated by QCP. With the slow development of the tamponade, the SBM model are seen to disagree while the

  7. An overview of analytical techniques and methods for the study and preservation of artistic and archaeological bronzes.

    NASA Astrophysics Data System (ADS)

    Mazzeo, Rocco; Prati, Silvia; Quaranta, Marta; Sciutto, Giorgia

    The present review intends to give an overview on the type of information that is possible to gather from the application of different non-invasive and micro-destructive analytical techniques. Typically, methods that require the withdrawal of a sample, such as metallography, SEM-EDS, AAS, FTIR and Py-GC-MS are employed. Through their use, it is possible to identify the material constitution, to evaluate the degradation behavior and the state of conservation of excavated bronze artefacts. It is also underlined how a non-invasive approach might be used whenever no sampling is allowed, though some limitation should be considered. Furthermore, analytical techniques play an important role in the characterisation and evaluation of the effectiveness of protective coatings and corrosion inhibitors before and after restoration procedures. An interesting aspect is the implication of science for the recognition of forgeries, when analytical studies provide evidences able to prove or deny objects' authenticity.

  8. Standardisation of elemental analytical techniques applied to provenance studies of archaeological ceramics: an inter laboratory calibration study.

    PubMed

    Hein, A; Tsolakidou, A; Iliopoulos, I; Mommsen, H; Buxeda i Garrigós, J; Montana, G; Kilikoglou, V

    2002-04-01

    Chemical analysis is a well-established procedure for the provenancing of archaeological ceramics. Various analytical techniques are routinely used and large amounts of data have been accumulated so far in data banks. However, in order to exchange results obtained by different laboratories, the respective analytical procedures need to be tested in terms of their inter-comparability. In this study, the schemes of analysis used in four laboratories that are involved in archaeological pottery studies on a routine basis were compared. The techniques investigated were neutron activation analysis (NAA), X-ray fluorescence analysis (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). For this comparison series of measurements on different geological standard reference materials (SRM) were carried out and the results were statistically evaluated. An attempt was also made towards the establishment of calibration factors between pairs of analytical setups in order to smooth the systematic differences among the results.

  9. A Decision Analytic Approach to Exposure-Based Chemical ...

    EPA Pesticide Factsheets

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. The National Exposure Research Laboratory′s (NERL′s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in suppor

  10. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    PubMed Central

    Mitchell, Jade; Pabon, Nicolas; Collier, Zachary A.; Egeghy, Peter P.; Cohen-Hubal, Elaine; Linkov, Igor; Vallero, Daniel A.

    2013-01-01

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. PMID:23940664

  11. Solid analyte and aqueous solutions sensing based on a flexible terahertz dual-band metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Yan, Xin; Liang, Lan-Ju; Ding, Xin; Yao, Jian-Quan

    2017-02-01

    A high-sensitivity sensing technique was demonstrated based on a flexible terahertz dual-band metamaterial absorber. The absorber has two perfect absorption peaks, one with a fundamental resonance (f1) of the structure and another with a high-order resonance (f2) originating from the interactions of adjacent unit cells. The quality factor (Q) and figure of merit of f2 are 6 and 14 times larger than that of f1, respectively. For the solid analyte, the changes in resonance frequency are monitored upon variation of analyte thickness and index; a linear relation between the amplitude absorption with the analyte thickness is achieved for f2. The sensitivity (S) is 31.2% refractive index units (RIU-1) for f2 and 13.7% RIU-1 for f1. For the aqueous solutions, the amplitude of absorption decreases linearly with increasing the dielectric constant for the ethanol-water mixture of f1. These results show that the designed absorber cannot only identify a solid analyte but also characterize aqueous solutions through the frequency shift and amplitude absorption. Therefore, the proposed absorber is promising for future applications in high-sensitivity monitoring biomolecular, chemical, ecological water systems, and aqueous biosystems.

  12. Rapid detection of transition metals in welding fumes using paper-based analytical devices.

    PubMed

    Cate, David M; Nanthasurasak, Pavisara; Riwkulkajorn, Pornpak; L'Orange, Christian; Henry, Charles S; Volckens, John

    2014-05-01

    Metals in particulate matter (PM) are considered a driving factor for many pathologies. Despite the hazards associated with particulate metals, personal exposures for at-risk workers are rarely assessed due to the cost and effort associated with monitoring. As a result, routine exposure assessments are performed for only a small fraction of the exposed workforce. The objective of this research was to evaluate a relatively new technology, microfluidic paper-based analytical devices (µPADs), for measuring the metals content in welding fumes. Fumes from three common welding techniques (shielded metal arc, metal inert gas, and tungsten inert gas welding) were sampled in two welding shops. Concentrations of acid-extractable Fe, Cu, Ni, and Cr were measured and independently verified using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results from the µPAD sensors agreed well with ICP-OES analysis; the two methods gave statistically similar results in >80% of the samples analyzed. Analytical costs for the µPAD technique were ~50 times lower than market-rate costs with ICP-OES. Further, the µPAD method was capable of providing same-day results (as opposed several weeks for ICP laboratory analysis). Results of this work suggest that µPAD sensors are a viable, yet inexpensive alternative to traditional analytic methods for transition metals in welding fume PM. These sensors have potential to enable substantially higher levels of hazard surveillance for a given resource cost, especially in resource-limited environments.

  13. Rapid Detection of Transition Metals in Welding Fumes Using Paper-Based Analytical Devices

    PubMed Central

    Volckens, John

    2014-01-01

    Metals in particulate matter (PM) are considered a driving factor for many pathologies. Despite the hazards associated with particulate metals, personal exposures for at-risk workers are rarely assessed due to the cost and effort associated with monitoring. As a result, routine exposure assessments are performed for only a small fraction of the exposed workforce. The objective of this research was to evaluate a relatively new technology, microfluidic paper-based analytical devices (µPADs), for measuring the metals content in welding fumes. Fumes from three common welding techniques (shielded metal arc, metal inert gas, and tungsten inert gas welding) were sampled in two welding shops. Concentrations of acid-extractable Fe, Cu, Ni, and Cr were measured and independently verified using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results from the µPAD sensors agreed well with ICP-OES analysis; the two methods gave statistically similar results in >80% of the samples analyzed. Analytical costs for the µPAD technique were ~50 times lower than market-rate costs with ICP-OES. Further, the µPAD method was capable of providing same-day results (as opposed several weeks for ICP laboratory analysis). Results of this work suggest that µPAD sensors are a viable, yet inexpensive alternative to traditional analytic methods for transition metals in welding fume PM. These sensors have potential to enable substantially higher levels of hazard surveillance for a given resource cost, especially in resource-limited environments. PMID:24515892

  14. Analytical and knowledge-based redundancy for fault diagnosis in process plants

    SciTech Connect

    Fathi, Z.; Ramirez, W.F. ); Korbicz, J. )

    1993-01-01

    The increasing complexity of process plants and their reliability have necessitated the development of more powerful methods for detecting and diagnosing process abnormalities. Among the underlying strategies, analytical redundancy and knowledge-based system techniques offer viable solutions. In this work, the authors consider the adaptive inclusion of analytical redundancy models (state and parameter estimation modules) in the diagnostic reasoning loop of a knowledge-based system. This helps overcome the difficulties associated with each category. The design method is a new layered knowledge base that houses compiled/qualitative knowledge in the high levels and process-general estimation knowledge in the low levels of a hierarchical knowledge structure. The compiled knowledge is used to narrow the diagnostic search space and provide an effective way of employing estimation modules. The estimation-based methods that resort to fundamental analysis provide the rationale for a qualitatively-guided reasoning process. The overall structure of the fault detection and isolation system based on the combined strategy is discussed focusing on the model-based redundancy methods which create the low levels of the hierarchical knowledge base. The system has been implemented using the condensate-feedwater subsystem of a coal-fired power plant. Due to the highly nonlinear and mixed-mode nature of the power plant dynamics, the modified extended Kalman filter is used in designing local detection filters.

  15. A physically based analytical model of flood frequency curves

    NASA Astrophysics Data System (ADS)

    Basso, S.; Schirmer, M.; Botter, G.

    2016-09-01

    Predicting magnitude and frequency of floods is a key issue in hydrology, with implications in many fields ranging from river science and geomorphology to the insurance industry. In this paper, a novel physically based approach is proposed to estimate the recurrence intervals of seasonal flow maxima. The method links the extremal distribution of streamflows to the stochastic dynamics of daily discharge, providing an analytical expression of the seasonal flood frequency curve. The parameters involved in the formulation embody climate and landscape attributes of the contributing catchment and can be estimated from daily rainfall and streamflow data. Only one parameter, which is linked to the antecedent wetness condition in the watershed, needs to be calibrated on the observed maxima. The performance of the method is discussed through a set of applications in four rivers featuring heterogeneous daily flow regimes. The model provides reliable estimates of seasonal maximum flows in different climatic settings and is able to capture diverse shapes of flood frequency curves emerging in erratic and persistent flow regimes. The proposed method exploits experimental information on the full range of discharges experienced by rivers. As a consequence, model performances do not deteriorate when the magnitude of events with return times longer than the available sample size is estimated. The approach provides a framework for the prediction of floods based on short data series of rainfall and daily streamflows that may be especially valuable in data scarce regions of the world.

  16. Analytical investigation of bilayer lipid biosensor based on graphene.

    PubMed

    Akbari, Elnaz; Buntat, Zolkafle; Shahraki, Elmira; Parvaz, Ramtin; Kiani, Mohammad Javad

    2016-01-01

    Graphene is another allotrope of carbon with two-dimensional monolayer honeycomb. Owing to its special characteristics including electrical, physical and optical properties, graphene is known as a more suitable candidate compared to other materials to be used in the sensor application. It is possible, moreover, to use biosensor by using electrolyte-gated field effect transistor based on graphene (GFET) to identify the alterations in charged lipid membrane properties. The current article aims to show how thickness and charges of a membrane electric can result in a monolayer graphene-based GFET while the emphasis is on the conductance variation. It is proposed that the thickness and electric charge of the lipid bilayer (LLP and QLP) are functions of carrier density, and to find the equation relating these suitable control parameters are introduced. Artificial neural network algorithm as well as support vector regression has also been incorporated to obtain other models for conductance characteristic. The results comparison between analytical models, artificial neural network and support vector regression with the experimental data extracted from previous work show an acceptable agreement.

  17. What if Learning Analytics Were Based on Learning Science?

    ERIC Educational Resources Information Center

    Marzouk, Zahia; Rakovic, Mladen; Liaqat, Amna; Vytasek, Jovita; Samadi, Donya; Stewart-Alonso, Jason; Ram, Ilana; Woloshen, Sonya; Winne, Philip H.; Nesbit, John C.

    2016-01-01

    Learning analytics are often formatted as visualisations developed from traced data collected as students study in online learning environments. Optimal analytics inform and motivate students' decisions about adaptations that improve their learning. We observe that designs for learning often neglect theories and empirical findings in learning…

  18. What if Learning Analytics Were Based on Learning Science?

    ERIC Educational Resources Information Center

    Marzouk, Zahia; Rakovic, Mladen; Liaqat, Amna; Vytasek, Jovita; Samadi, Donya; Stewart-Alonso, Jason; Ram, Ilana; Woloshen, Sonya; Winne, Philip H.; Nesbit, John C.

    2016-01-01

    Learning analytics are often formatted as visualisations developed from traced data collected as students study in online learning environments. Optimal analytics inform and motivate students' decisions about adaptations that improve their learning. We observe that designs for learning often neglect theories and empirical findings in learning…

  19. Two Analyte Calibration From The Transient Response Of Potentiometric Sensors Employed With The SIA Technique

    SciTech Connect

    Cartas, Raul; Mimendia, Aitor; Valle, Manel del; Legin, Andrey

    2009-05-23

    Calibration models for multi-analyte electronic tongues have been commonly built using a set of sensors, at least one per analyte under study. Complex signals recorded with these systems are formed by the sensors' responses to the analytes of interest plus interferents, from which a multivariate response model is then developed. This work describes a data treatment method for the simultaneous quantification of two species in solution employing the signal from a single sensor. The approach used here takes advantage of the complex information recorded with one electrode's transient after insertion of sample for building the calibration models for both analytes. The departure information from the electrode was firstly processed by discrete wavelet for transforming the signals to extract useful information and reduce its length, and then by artificial neural networks for fitting a model. Two different potentiometric sensors were used as study case for simultaneously corroborating the effectiveness of the approach.

  20. Toward Theoretical Techniques for Measuring the Use of Human Effort in Visual Analytic Systems.

    PubMed

    Crouser, R Jordan; Franklin, Lyndsey; Endert, Alex; Cook, Kris

    2017-01-01

    Visual analytic systems have long relied on user studies and standard datasets to demonstrate advances to the state of the art, as well as to illustrate the efficiency of solutions to domain-specific challenges. This approach has enabled some important comparisons between systems, but unfortunately the narrow scope required to facilitate these comparisons has prevented many of these lessons from being generalized to new areas. At the same time, advanced visual analytic systems have made increasing use of human-machine collaboration to solve problems not tractable by machine computation alone. To continue to make progress in modeling user tasks in these hybrid visual analytic systems, we must strive to gain insight into what makes certain tasks more complex than others. This will require the development of mechanisms for describing the balance to be struck between machine and human strengths with respect to analytical tasks and workload. In this paper, we argue for the necessity of theoretical tools for reasoning about such balance in visual analytic systems and demonstrate the utility of the Human Oracle Model for this purpose in the context of sensemaking in visual analytics. Additionally, we make use of the Human Oracle Model to guide the development of a new system through a case study in the domain of cybersecurity.

  1. Formal specification of requirements for analytical redundancy-based fault-tolerant flight control systems

    NASA Astrophysics Data System (ADS)

    Del Gobbo, Diego

    2000-10-01

    Flight control systems are undergoing a rapid process of automation. The use of Fly-By-Wire digital flight control systems in commercial aviation (Airbus 320 and Boeing FBW-B777) is a clear sign of this trend. The increased automation goes in parallel with an increased complexity of flight control systems with obvious consequences on reliability and safety. Flight control systems must meet strict fault-tolerance requirements. The standard solution to achieving fault tolerance capability relies on multi-string architectures. On the other hand, multi-string architectures further increase the complexity of the system inducing a reduction of overall reliability. In the past two decades a variety of techniques based on analytical redundancy have been suggested for fault diagnosis purposes. While research on analytical redundancy has obtained desirable results, a design methodology involving requirements specification and feasibility analysis of analytical redundancy based fault tolerant flight control systems is missing. The main objective of this research work is to describe within a formal framework the implications of adopting analytical redundancy as a basis to achieve fault tolerance. The research activity involves analysis of the analytical redundancy approach, analysis of flight control system informal requirements, and re-engineering (modeling and specification) of the fault tolerance requirements. The USAF military specification MIL-F-9490D and supporting documents are adopted as source for the flight control informal requirements. The De Havilland DHC-2 general aviation aircraft equipped with standard autopilot control functions is adopted as pilot application. Relational algebra is adopted as formal framework for the specification of the requirements. The detailed analysis and formalization of the requirements resulted in a better definition of the fault tolerance problem in the framework of analytical redundancy. Fault tolerance requirements and related

  2. Experimental and analytical temperature distributions during oven-based convection heating.

    PubMed

    McCarthy, Kathryn L; McCarthy, Michael J; Rakesh, Vineet; Datta, Ashim K

    2010-01-01

    Mathematical models, combined with experimental evaluation, provide an approach to understand, design, and optimize food process operations. Magnetic resonance imaging (MRI), as an experimental technique, is used extensively in both medical and engineering applications to measure and quantify transport processes. Magnetic resonance (MR) was used in this study to assess a mathematical model based on Fourier's second law. The objective was to compare analytical solutions for the prediction of internal temperature distributions in foods during oven-based convective heating to experimental temperature measurements and determine at what point during the heating process a coupled heat and mass transport process should be considered. Cylindrical samples of a model food gel, Russet potato and rehydrated mashed potato were heated in a convection oven for specified times. Experimentally measured internal temperatures were compared to the internal temperatures predicted by the analytical model. Temperatures distributions in the axial direction compared favorably for the gel and acceptably for the Russet and mashed potato samples. The MR-acquired temperatures in the radial direction for the gel resulted in a shallower gradient than predicted but followed the expected trend. For the potato samples, the MR-acquired temperatures in the radial direction were not qualitatively similar to the analytical predictions due to moisture loss during heating. If temperature resolution is required in the radial direction, moisture losses merit the use of transport models that couple heat and mass transfer.

  3. A smog chamber comparison of a microfluidic derivatisation measurement of gas-phase glyoxal and methylglyoxal with other analytical techniques

    NASA Astrophysics Data System (ADS)

    Pang, xiaobing; Lewis, Alastair; Rickard, Andrew R.; Baeza-Romero, Maria Teresa; Adams, Thomas J.; Ball, Stephen M.; Goodall, Iain C. A.; Monks, Paul S.; Peppe, Salvatore; Ródenas García, Milagros; Sánchez, Pilar; Muñoz, Amalia

    2014-05-01

    A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation reagent and a microfabricated planar glass micro-reactor comprising an inlet, gas and fluid splitting and combining channels, mixing junctions, and a heated capillary reaction microchannel. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the micro-reactor result in a fast and highly efficient derivatisation reaction, generating an effluent stream ready for direct introduction to a gas chromatograph-mass spectrometer (GC-MS). A linear response for GLY was observed over a calibration range 0.7 to 400 ppbV, and for MGLY of 1.2 to 300 ppbV, when derivatised under optimal reaction conditions. The analytical performance shows good accuracy (6.6 % for GLY and 7.5 % for MGLY), suitable precision (< 12.0 %) and method detection limits (MDLs) (75 pptV for GLY and 185 pptV for MGLY) with a time resolution of 30 minutes. These MDLs are below or close to typical concentrations of these compounds observed in ambient air. The microfluidic derivatisation technique would be appropriate for ambient α-dicarbonyl measurements in a range of field environments based on its performance in a large-scale outdoor atmospheric simulation chamber (EUPHORE). The feasibility of the technique was assessed by applying the methodology to quantify of α-dicarbonyls formed during the photo-oxidation of isoprene in the EUPHORE chamber. Good correlations were found between microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR) with the correlation coefficient (r2) of 0.84, Broad Band Cavity Enhanced Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro extraction (SPME) (r2 = 0.89), and a

  4. Electrochemiluminescence detection in microfluidic cloth-based analytical devices.

    PubMed

    Guan, Wenrong; Liu, Min; Zhang, Chunsun

    2016-01-15

    This work describes the first approach at combining microfluidic cloth-based analytical devices (μCADs) with electrochemiluminescence (ECL) detection. Wax screen-printing is employed to make cloth-based microfluidic chambers which are patterned with carbon screen-printed electrodes (SPEs) to create truly disposable, simple, inexpensive sensors which can be read with a low-cost, portable charge coupled device (CCD) imaging sensing system. And, the two most commonly used ECL systems of tris(2,2'-bipyridyl)ruthenium(II)/tri-n-propylamine (Ru(bpy)3(2+)/TPA) and 3-aminophthalhydrazide/hydrogen peroxide (luminol/H2O2) are applied to demonstrate the quantitative ability of the ECL μCADs. In this study, the proposed devices have successfully fulfilled the determination of TPA with a linear range from 2.5 to 2500μM with a detection limit of 1.265μM. In addition, the detection of H2O2 can be performed in the linear range of 0.05-2.0mM, with a detection limit of 0.027mM. It has been shown that the ECL emission on the wax-patterned cloth device has an acceptable sensitivity, stability and reproducibility. Finally, the applicability of cloth-based ECL is demonstrated for determination of glucose in phosphate buffer solution (PBS) and artificial urine (AU) samples, with the detection limits of 0.032mM and 0.038mM, respectively. It can be foreseen, therefore, that μCADs with ECL detection could provide a new sensing platform for point-of-care testing, public health, food safety detection and environmental monitoring in remote regions, developing or developed countries.

  5. Fault detection and isolation of PEM fuel cell system based on nonlinear analytical redundancy. An application via parity space approach

    NASA Astrophysics Data System (ADS)

    Aitouche, A.; Yang, Q.; Ould Bouamama, B.

    2011-05-01

    This paper presents a procedure dealing with the issue of fault detection and isolation (FDI) using nonlinear analytical redundancy (NLAR) technique applied in a proton exchange membrane (PEM) fuel cell system based on its mathematic model. The model is proposed and simplified into a five orders state space representation. The transient phenomena captured in the model include the compressor dynamics, the flow characteristics, mass and energy conservation and manifold fluidic mechanics. Nonlinear analytical residuals are generated based on the elimination of the unknown variables of the system by an extended parity space approach to detect and isolate actuator and sensor faults. Finally, numerical simulation results are given corresponding to a faults signature matrix.

  6. Loading of red blood cells with an analyte-sensitive dye for development of a long-term monitoring technique

    NASA Astrophysics Data System (ADS)

    Ritter, Sarah C.; Meissner, Kenith E.

    2012-03-01

    Measurement of blood analytes, such as pH and glucose, provide crucial information about a patient's health. Some such analytes, such as glucose in the case of diabetes, require long-term or near-continuous monitoring for proper disease management. However, current monitoring techniques are far from ideal: multiple-per-day finger stick tests are inconvenient and painful for the patient; implantable sensors have short functional life spans (i.e., 3-7 days). Red blood cells serve as an attractive alternative for carriers of analyte sensors. Once reintroduced to the blood stream, these carriers may continue to live for the remainder of their life span (120 days for humans). They are also biodegradable and biocompatible, thereby eliminating the immune system response common for many implanted devices. The proposed carrier system takes advantage of the ability of the red blood cells to swell in response to a decrease in the osmolarity of the extracellular solution. Just before the membranes lyse, they develop small pores on the scale of tens of nanometers. Analyte-sensitive dyes in the extracellular solution may then diffuse into the perforated red blood cells and become entrapped upon restoration of physiological temperature and osmolarity. Because the membranes contain various analyte transporters, intracellular analyte levels rapidly equilibrate to those of the extracellular solution. A fluorescent dye has been loaded inside of red blood cells using a preswelling technique. Alterations in preparation parameters have been shown to affect characteristics of the resulting dye-loaded red blood cells (e.g., intensity of fluorescence).

  7. Multi-technique surface analytical studies of automotive anti-wear films

    NASA Astrophysics Data System (ADS)

    Smith, G. C.; Bell, J. C.

    1999-04-01

    A multi-technique study of model automotive anti-wear films using SEM with quantitative electron microprobe analysis, reflection-absorption IR spectroscopy, SIMS imaging and XPS depth profiling is described. Constrained simulation of the XPS depth profiles allowed model cross-sections of the film structures to be constructed. With zinc dialkyl dithiophosphate as an anti-wear additive, the anti-wear films were found to have a thin inorganic mixed sulphide/oxide layer immediately above the Fe substrate. This formed the base for a thicker Zn-containing polyphosphate-like overlayer. Addition of detergent and dispersant to the lubricant formulation resulted in thicker, more patchy films, with a clearer differentiation between film and substrate.

  8. Insulator-based DEP with impedance measurements for analyte detection

    DOEpatents

    Davalos, Rafael V.; Simmons, Blake A.; Crocker, Robert W.; Cummings, Eric B.

    2010-03-16

    Disclosed herein are microfluidic devices for assaying at least one analyte specie in a sample comprising at least one analyte concentration area in a microchannel having insulating structures on or in at least one wall of the microchannel which provide a nonuniform electric field in the presence of an electric field provided by off-chip electrodes; and a pair of passivated sensing electrodes for impedance detection in a detection area. Also disclosed are assay methods and methods of making.

  9. Inspiraling black-hole binary spacetimes: Challenges in transitioning from analytical to numerical techniques

    NASA Astrophysics Data System (ADS)

    Zlochower, Yosef; Nakano, Hiroyuki; Mundim, Bruno C.; Campanelli, Manuela; Noble, Scott; Zilhão, Miguel

    2016-06-01

    We explore how a recently developed analytical black-hole binary spacetime can be extended using numerical simulations to go beyond the slow-inspiral phase. The analytic spacetime solves the Einstein field equations approximately, with the approximation error becoming progressively smaller the more separated the binary. To continue the spacetime beyond the slow-inspiral phase, we need to transition. Such a transition was previously explored at smaller separations. Here, we perform this transition at a separation of D =20 M (large enough that the analytical metric is expected to be accurate), and evolve for six orbits. We find that small constraint violations can have large dynamical effects, but these can be removed by using a constraint-damping system like the conformal covariant formulation of the Z4 system. We find agreement between the subsequent numerical spacetime and the predictions of post-Newtonian theory for the waveform and inspiral rate that is within the post-Newtonian truncation error.

  10. Chemical and process mineralogical characterizations of spent lithium-ion batteries: an approach by multi-analytical techniques.

    PubMed

    Zhang, Tao; He, Yaqun; Wang, Fangfang; Ge, Linhan; Zhu, Xiangnan; Li, Hong

    2014-06-01

    Mineral processing operation is a critical step in any recycling process to realize liberation, separation and concentration of the target parts. Developing effective recycling methods to recover all the valuable parts from spent lithium-ion batteries is in great necessity. The aim of this study is to carefully undertake chemical and process mineralogical characterizations of spent lithium-ion batteries by coupling several analytical techniques to provide basic information for the researches on effective mechanical crushing and separation methods in recycling process. The results show that the grade of Co, Cu and Al is fairly high in spent lithium ion batteries and up to 17.62 wt.%, 7.17 wt.% and 21.60 wt.%. Spent lithium-ion batteries have good selective crushing property, the crushed products could be divided into three parts, they are Al-enriched fraction (+2 mm), Cu and Al-enriched fraction (-2+0.25 mm) and Co and graphite-enriched fraction (-0.25 mm). The mineral phase and chemical state analysis reveal the electrode materials recovered from -0.25 mm size fraction keep the original crystal forms and chemical states in lithium-ion batteries, but the surface of the powders has been coated by a certain kind of hydrocarbon. Based on these results a flowsheet to recycle spent LiBs is proposed.

  11. An evaluation of analytical methods, air sampling techniques, and airborne occupational exposure of metalworking fluids.

    PubMed

    Verma, Dave K; Shaw, Don S; Shaw, M Lorraine; Julian, Jim A; McCollin, Shari-Ann; des Tombe, Karen

    2006-02-01

    This article summarizes an assessment of air sampling and analytical methods for both oil and water-based metalworking fluids (MWFs). Three hundred and seventy-four long-term area and personal airborne samples were collected at four plants using total (closed-face) aerosol samplers and thoracic samplers. A direct-reading device (DustTrak) was also used. The processes sampled include steel tube making, automotive component manufacturing, and small part manufacturing in a machine shop. The American Society for Testing and Materials (ASTM) Method PS42-97 of analysis was evaluated in the laboratory. This evaluation included sample recovery, determination of detection limits, and stability of samples during storage. Results of the laboratory validation showed (a) the sample recovery to be about 87%, (b) the detection limit to be 35 microg, and (c) sample stability during storage at room temperature to decline rapidly within a few days. To minimize sample loss, the samples should be stored in a freezer and analyzed within a week. The ASTM method should be the preferred method for assessing metalworking fluids (MWFs). The ratio of thoracic aerosol to total aerosol ranged from 0.6 to 0.7. A similar relationship was found between the thoracic extractable aerosol and total extractable aerosol. The DustTrak, with 10-microm sampling head, was useful in pinpointing the areas of potential exposure. MWF exposure at the four plants ranged from 0.04 to 3.84 mg/m3 with the geometric mean ranging between 0.22 to 0.59 mg/m3. Based on this data and the assumption of log normality, MWF exposures are expected to exceed the National Institute for Occupational Safety and Health recommended exposure limit of 0.5 mg/m3 as total mass and 0.4 mg/m3 as thoracic mass about 38% of the time. In addition to controlling airborne MWF exposure, full protection of workers would require the institution of programs for fluid management and dermal exposure prevention.

  12. Experimental, computational, and analytical techniques for diagnosing breast cancer using optical spectroscopy

    NASA Astrophysics Data System (ADS)

    Palmer, Gregory M.

    This dissertation presents the results of an investigation into experimental, computational, and analytical methodologies for diagnosing breast cancer using fluorescence and diffuse reflectance spectroscopy. First, the optimal experimental methodology for tissue biopsy studies was determined using an animal study. It was found that the use of freshly excised tissue samples preserved the original spectral line shape and magnitude of the fluorescence and diffuse reflectance. Having established the optimal experimental methodology, a clinical study investigating the use of fluorescence and diffuse reflectance spectroscopy for the diagnosis of breast cancer was undertaken. In addition, Monte Carlo-based models of diffuse reflectance and fluorescence were developed and validated to interpret these data. These models enable the extraction of physically meaningful information from the measured spectra, including absorber concentrations, and scattering and intrinsic fluorescence properties. The model was applied to the measured spectra, and using a support vector machine classification algorithm based on physical features extracted from the diffuse reflectance spectra, it was found that breast cancer could be diagnosed with a cross-validated sensitivity and specificity of 82% and 92%, respectively, which are substantially better than that obtained using a conventional, empirical algorithm. It was found that malignant tissues had lower hemoglobin oxygen saturation, were more scattering, and had lower beta-carotene concentration, relative to the non-malignant tissues. It was also found that the fluorescence model could successfully extract the intrinsic fluorescence line shape from tissue samples. One limitation of the previous study is that a priori knowledge of the tissue's absorbers and scatterers is required. To address this limitation, and to improve upon the method with which fiber optic probes are designed, an alternate approach was developed. This method used a

  13. Solution of prey-predator problem by numeric-analytic technique

    NASA Astrophysics Data System (ADS)

    Chowdhury, M. S. H.; Hashim, I.; Mawa, S.

    2009-04-01

    In this paper, an analytical expression for the solution of the prey-predator problem by an adaptation of the classical Adomian decomposition method (ADM). The ADM is treated as an algorithm for approximating the solution of the problem in a sequence of time intervals, i.e. the classical ADM is converted into a hybrid numeric-analytic method called the multistage ADM (MADM). Numerical comparisons with the classical ADM, and the classical fourth-order Rungge-Kutta (RK4) methods are presented.

  14. The Studies of Archaeological Pottery with the Use of Selected Analytical Techniques.

    PubMed

    Kałużna-Czaplińska, Joanna; Rosiak, Angelina; Grams, Jacek; Chałupka, Karolina; Makarowicz, Przemysław; Maniukiewicz, Waldemar; Szubiakiewicz, Elżbieta

    2017-05-25

    Modern analytical methods play an important role in archaeological objects, including ceramics. This review focuses on the use of analytical methods such as: gas chromatography coupled mass spectrometry, Fourier transform infrared spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), powder X-ray diffraction with thermal analysis to study the chemical and mineralogical composition of archaeological samples and organic residues preserved inside. In this paper, special attention was paid to the ToF-SIMS method, which allows the determination of characteristic ions on the surface of ceramic samples.

  15. Rapid Late Holocene glacier fluctuations reconstructed from South Georgia lake sediments using novel analytical and numerical techniques

    NASA Astrophysics Data System (ADS)

    van der Bilt, Willem; Bakke, Jostein; Werner, Johannes; Paasche, Øyvind; Rosqvist, Gunhild

    2016-04-01

    synchronous bi-polar Little Ice Age (LIA). In conclusion, our work shows the potential of novel analytical and numerical tools to improve the robustness and resolution of lake sediment-based paleoclimate reconstructions beyond the current state-of-the-art.

  16. An Analytical Model of Wave-Induced Longshore Current Based on Power Law Wave Height Decay.

    DTIC Science & Technology

    1988-01-01

    34I ANALYtTICAL MODEL OF NAVE-INDUCED LON6SHORE CURRENT BASED ON PONE* LAW.. (U) COASTAL ENG INEERING RESEAKNH CENTER VICKSBURG NS J N SMITH ET AL...j . - .L .V . : ; * AN ANALYTICAL MODEL OF WAVE-INDUCED ~ z * LONGSHORE CURRENT BASED ON POWER LAW * - WAVE HEIGHT DECAY by Jane McKee...I_ I IF 31592 11. TITLE (Include Security Classfication) • An Analytical Model of Wave-Induced Longshore Current Based on Power Law . Wave

  17. The use of surface analytical techniques to measure the loadings of uranium and plutonium sorbed simultaneously from solution onto rocks

    SciTech Connect

    Berry, J.A.; Bishop, H.E.; Cowper, M.M.; Fozard, P.R.; McMillan, J.W.

    1995-12-31

    Small polished blocks of granite, diorite and dolerite were immersed in solutions containing uranium and plutonium at equal initial concentration.The samples were analyzed by the advanced surface analytical techniques of secondary ion mass spectrometry (SIMS) and nuclear microprobe analysis. The results show that both actinides sorb onto the same minerals in the three rocks. However, SIMS data show that significantly more uranium was sorbed than plutonium.

  18. Analytical techniques for the study of some parameters of multispectral scanner systems for remote sensing

    NASA Technical Reports Server (NTRS)

    Wiswell, E. R.; Cooper, G. R. (Principal Investigator)

    1978-01-01

    The author has identified the following significant results. The concept of average mutual information in the received spectral random process about the spectral scene was developed. Techniques amenable to implementation on a digital computer were also developed to make the required average mutual information calculations. These techniques required identification of models for the spectral response process of scenes. Stochastic modeling techniques were adapted for use. These techniques were demonstrated on empirical data from wheat and vegetation scenes.

  19. A Content Analytic Technique for Measuring the Sexiness of Women's Business Attire in Media Presentations.

    ERIC Educational Resources Information Center

    White, Sylvia E.

    1995-01-01

    Describes development of an objective content analytic category scheme for measuring the sexiness of women's business attire in media presentations. Finds women's business attire in television soap operas significantly more provocative than real-world attire. Finds a significant positive correlation between the degree of sexiness as measured by…

  20. Implementation of IAEA /1/INT/054 Project in Nuclear Analytical Techniques Group of Argentina: Current State

    SciTech Connect

    Sara, Resnizky; Rita, Pla; Alba, Zaretzky

    2008-08-14

    This paper presents the implementation of the training received through the IAEA Project 'Preparation of Reference Materials and Organization of Proficiency Tests Rounds' in the Nuclear Analytical (NAT) Group of CNEA. Special emphasis is done on those activities related to the first Proficiency Test being carried out by the NAT Group.

  1. Implementation of IAEA /1/INT/054 Project in Nuclear Analytical Techniques Group of Argentina: Current State

    NASA Astrophysics Data System (ADS)

    Sara, Resnizky; Rita, Plá; Alba, Zaretzky

    2008-08-01

    This paper presents the implementation of the training received through the IAEA Project "Preparation of Reference Materials and Organization of Proficiency Tests Rounds" in the Nuclear Analytical (NAT) Group of CNEA. Special emphasis is done on those activities related to the first Proficiency Test being carried out by the NAT Group.

  2. Blood separation on microfluidic paper-based analytical devices.

    PubMed

    Songjaroen, Temsiri; Dungchai, Wijitar; Chailapakul, Orawon; Henry, Charles S; Laiwattanapaisal, Wanida

    2012-09-21

    A microfluidic paper-based analytical device (μPAD) for the separation of blood plasma from whole blood is described. The device can separate plasma from whole blood and quantify plasma proteins in a single step. The μPAD was fabricated using the wax dipping method, and the final device was composed of a blood separation membrane combined with patterned Whatman No.1 paper. Blood separation membranes, LF1, MF1, VF1 and VF2 were tested for blood separation on the μPAD. The LF1 membrane was found to be the most suitable for blood separations when fabricating the μPAD by wax dipping. For blood separation, the blood cells (both red and white) were trapped on blood separation membrane allowing pure plasma to flow to the detection zone by capillary force. The LF1-μPAD was shown to be functional with human whole blood of 24-55% hematocrit without dilution, and effectively separated blood cells from plasma within 2 min when blood volumes of between 15-22 μL were added to the device. Microscopy was used to confirm that the device isolated plasma with high purity with no blood cells or cell hemolysis in the detection zone. The efficiency of blood separation on the μPAD was studied by plasma protein detection using the bromocresol green (BCG) colorimetric assay. The results revealed that protein detection on the μPAD was not significantly different from the conventional method (p > 0.05, pair t-test). The colorimetric measurement reproducibility on the μPAD was 2.62% (n = 10) and 5.84% (n = 30) for within-day and between day precision, respectively. Our proposed blood separation on μPAD has the potential for reducing turnaround time, sample volume, sample preparation and detection processes for clinical diagnosis and point-of care testing.

  3. Project-Based Curriculum for Teaching Analytical Design to Freshman Engineering Students via Reconfigurable Trebuchets

    ERIC Educational Resources Information Center

    Herber, Daniel R.; Deshmukh, Anand P.; Mitchell, Marlon E.; Allison, James T.

    2016-01-01

    This paper presents an effort to revitalize a large introductory engineering course for incoming freshman students that teaches them analytical design through a project-based curriculum. This course was completely transformed from a seminar-based to a project-based course that integrates hands-on experimentation with analytical work. The project…

  4. Terracotta polychrome sculptures examined before and after their conservation work: contributions from non-invasive in situ analytical techniques.

    PubMed

    Colombo, C; Bevilacqua, F; Brambilla, L; Conti, C; Realini, M; Striova, J; Zerbi, G

    2011-08-01

    The potential of non-invasive in situ analytical techniques such as portable Raman, portable X-ray fluorescence, portable optical microscope and fibre optics reflectance spectroscopy has been shown studying painted layers of Renaissance terracotta polychrome sculptures belonging to the statuary of Santo Sepolcro Church in Milan. The results obtained allowed pointing out the contribution of these techniques to the compositional diagnostic, providing complete information, in some cases, better than micro-destructive techniques, on the kind of pigments used on the external painted layers. Moreover, a comparison with the results obtained before the last conservation work (2009) with micro-destructive techniques allowed ascertaining the removal of the external painted layers during the conservation operations.

  5. Interrogating Bronchoalveolar Lavage Samples via Exclusion-Based Analyte Extraction.

    PubMed

    Tokar, Jacob J; Warrick, Jay W; Guckenberger, David J; Sperger, Jamie M; Lang, Joshua M; Ferguson, J Scott; Beebe, David J

    2017-06-01

    Although average survival rates for lung cancer have improved, earlier and better diagnosis remains a priority. One promising approach to assisting earlier and safer diagnosis of lung lesions is bronchoalveolar lavage (BAL), which provides a sample of lung tissue as well as proteins and immune cells from the vicinity of the lesion, yet diagnostic sensitivity remains a challenge. Reproducible isolation of lung epithelia and multianalyte extraction have the potential to improve diagnostic sensitivity and provide new information for developing personalized therapeutic approaches. We present the use of a recently developed exclusion-based, solid-phase-extraction technique called SLIDE (Sliding Lid for Immobilized Droplet Extraction) to facilitate analysis of BAL samples. We developed a SLIDE protocol for lung epithelial cell extraction and biomarker staining of patient BALs, testing both EpCAM and Trop2 as capture antigens. We characterized captured cells using TTF1 and p40 as immunostaining biomarkers of adenocarcinoma and squamous cell carcinoma, respectively. We achieved up to 90% (EpCAM) and 84% (Trop2) extraction efficiency of representative tumor cell lines. We then used the platform to process two patient BAL samples in parallel within the same sample plate to demonstrate feasibility and observed that Trop2-based extraction potentially extracts more target cells than EpCAM-based extraction.

  6. Wavelet-based technique for target segmentation

    NASA Astrophysics Data System (ADS)

    Sadjadi, Firooz A.

    1995-07-01

    Segmentation of targets embedded in clutter obtained by IR imaging sensors is one of the challenging problems in automatic target recognition (ATR). In this paper a new texture-based segmentation technique is presented that uses the statistics of 2D wavelet decomposition components of the lcoal sections of the image. A measure of statistical similarity is then used to segment the image and separate the target from the background. This technique is applied on a set of real sequential IR imagery and has shown to produce a high degree of segmentation accuracy across varying ranges.

  7. Analysis of low molecular weight metabolites in tea using mass spectrometry-based analytical methods.

    PubMed

    Fraser, Karl; Harrison, Scott J; Lane, Geoff A; Otter, Don E; Hemar, Yacine; Quek, Siew-Young; Rasmussen, Susanne

    2014-01-01

    Tea is the second most consumed beverage in the world after water and there are numerous reported health benefits as a result of consuming tea, such as reducing the risk of cardiovascular disease and many types of cancer. Thus, there is much interest in the chemical composition of teas, for example; defining components responsible for contributing to reported health benefits; defining quality characteristics such as product flavor; and monitoring for pesticide residues to comply with food safety import/export requirements. Covered in this review are some of the latest developments in mass spectrometry-based analytical techniques for measuring and characterizing low molecular weight components of tea, in particular primary and secondary metabolites. The methodology; more specifically the chromatography and detection mechanisms used in both targeted and non-targeted studies, and their main advantages and disadvantages are discussed. Finally, we comment on the latest techniques that are likely to have significant benefit to analysts in the future, not merely in the area of tea research, but in the analytical chemistry of low molecular weight compounds in general.

  8. Laboratory Techniques in Geology: Embedding Analytical Methods into the Undergraduate Curriculum

    NASA Astrophysics Data System (ADS)

    Baedke, S. J.; Johnson, E. A.; Kearns, L. E.; Mazza, S. E.; Gazel, E.

    2014-12-01

    Paid summer REU experiences successfully engage undergraduate students in research and encourage them to continue to graduate school and scientific careers. However these programs only accommodate a limited number of students due to funding constraints, faculty time commitments, and limited access to needed instrumentation. At JMU, the Department of Geology and Environmental Science has embedded undergraduate research into the curriculum. Each student fulfilling a BS in Geology or a BA in Earth Science completes 3 credits of research, including a 1-credit course on scientific communication, 2 credits of research or internship, followed by a presentation of that research. Our department has successfully acquired many analytical instruments and now has an XRD, SEM/EDS, FTIR, handheld Raman, AA, ion chromatograph, and an IRMS. To give as many students as possible an overview to the scientific uses and operation methods for these instruments, we revived a laboratory methods course that includes theory and practical use of instrumentation at JMU, plus XRF sample preparation and analysis training at Virginia Tech during a 1-day field trip. In addition to practical training, projects included analytical concepts such as evaluating analytical vs. natural uncertainty, determining error on multiple measurements, signal-to-noise ratio, and evaluating data quality. State funding through the 4-VA program helped pay for analytical supplies and support for students to complete research projects over the summer or during the next academic year using instrumentation from the course. This course exemplifies an alternative path to broadening participation in undergraduate research and creating stronger partnerships between PUI's and research universities.

  9. General technique for analytical derivatives of post-projected Hartree-Fock

    NASA Astrophysics Data System (ADS)

    Tsuchimochi, Takashi; Ten-no, Seiichiro

    2017-02-01

    In electronic structure theory, the availability of an analytical derivative is one of the desired features for a method to be useful in practical applications, as it allows for geometry optimization as well as computation of molecular properties. With the recent advances in the development of symmetry-projected Hartree-Fock (PHF) methods, we here aim at further extensions by devising the analytic gradients of post-PHF approaches with a special focus on spin-extended (spin-projected) configuration interaction with single and double substitutions (ECISD). Just like standard single-reference methods, the mean-field PHF part does not require the corresponding coupled-perturbed equation to be solved, while the correlation energy term needs the orbital relaxation effect to be accounted for, unless the underlying molecular orbitals are variationally optimized in the presence of the correlation energy. We present a general strategy for post-PHF analytical gradients, which closely parallels that for single-reference methods, yet addressing the major difference between them. The similarity between ECISD and multi-reference CI not only in the energy but also in the optimized geometry is clearly demonstrated by the numerical examples of ozone and cyclobutadiene.

  10. General technique for analytical derivatives of post-projected Hartree-Fock.

    PubMed

    Tsuchimochi, Takashi; Ten-No, Seiichiro

    2017-02-21

    In electronic structure theory, the availability of an analytical derivative is one of the desired features for a method to be useful in practical applications, as it allows for geometry optimization as well as computation of molecular properties. With the recent advances in the development of symmetry-projected Hartree-Fock (PHF) methods, we here aim at further extensions by devising the analytic gradients of post-PHF approaches with a special focus on spin-extended (spin-projected) configuration interaction with single and double substitutions (ECISD). Just like standard single-reference methods, the mean-field PHF part does not require the corresponding coupled-perturbed equation to be solved, while the correlation energy term needs the orbital relaxation effect to be accounted for, unless the underlying molecular orbitals are variationally optimized in the presence of the correlation energy. We present a general strategy for post-PHF analytical gradients, which closely parallels that for single-reference methods, yet addressing the major difference between them. The similarity between ECISD and multi-reference CI not only in the energy but also in the optimized geometry is clearly demonstrated by the numerical examples of ozone and cyclobutadiene.

  11. Prediction of Torque Pulsations in Brushless Permanent-Magnet Motors Using Improved Analytical Technique

    NASA Astrophysics Data System (ADS)

    Kiyoumarsi, Arash

    2010-01-01

    Torque pulsations have prominent effects on the performance of brushless permanent- magnet (PM) machines. There are different sources of torque ripples in PM motors. These torque pulsations depend on the shape of the flux density distribution in the airgap region. For predicting the open-circuit airgap field distribution in brushless PM motors, a two dimensional (2-D) analytical method, in which the direction of magnetization, either radial or parallel and the effect of the stator slot-openings are taken into account, is used. The method uses an improved 2-D permeance model. In order to evaluate the accuracy of this method, a 2-D time-stepping FEM coupled with the two motion equations is used. A 3-phase, 36-slot, 4-pole, 5 HP, brushless PM motor is modeled by two methods. In this analysis both, the radial and parallel magnetization of the brushless motor are considered. The results obtained by the analytical method are compared with those obtained by FE analysis that shows the valuable accuracy of the analytical method for performance calculations in design and optimization processes.

  12. Evaluation of Analytical Techniques for the Determination of Trace Elements in Marine Waters.

    DTIC Science & Technology

    capability of multielemental determination, and cost of analysis. The techniques are atomic absorption spectroscopy , neutron activation analysis, and x ray fluorescence analysis. (Modified author abstract)

  13. Exploring the Efficacy of Behavioral Skills Training to Teach Basic Behavior Analytic Techniques to Oral Care Providers

    ERIC Educational Resources Information Center

    Graudins, Maija M.; Rehfeldt, Ruth Anne; DeMattei, Ronda; Baker, Jonathan C.; Scaglia, Fiorella

    2012-01-01

    Performing oral care procedures with children with autism who exhibit noncompliance can be challenging for oral care professionals. Previous research has elucidated a number of effective behavior analytic procedures for increasing compliance, but some procedures are likely to be too time consuming and expensive for community-based oral care…

  14. Exploring the Efficacy of Behavioral Skills Training to Teach Basic Behavior Analytic Techniques to Oral Care Providers

    ERIC Educational Resources Information Center

    Graudins, Maija M.; Rehfeldt, Ruth Anne; DeMattei, Ronda; Baker, Jonathan C.; Scaglia, Fiorella

    2012-01-01

    Performing oral care procedures with children with autism who exhibit noncompliance can be challenging for oral care professionals. Previous research has elucidated a number of effective behavior analytic procedures for increasing compliance, but some procedures are likely to be too time consuming and expensive for community-based oral care…

  15. Video-Based Big Data Analytics in Cyberlearning

    ERIC Educational Resources Information Center

    Wang, Shuangbao; Kelly, William

    2017-01-01

    In this paper, we present a novel system, inVideo, for video data analytics, and its use in transforming linear videos into interactive learning objects. InVideo is able to analyze video content automatically without the need for initial viewing by a human. Using a highly efficient video indexing engine we developed, the system is able to analyze…

  16. Controlled Space Radiation concept for mesh-free semi-analytical technique to model wave fields in complex geometries.

    PubMed

    Banerjee, Sourav; Das, Samik; Kundu, Tribikram; Placko, Dominique

    2009-12-01

    Numerical modelling of the ultrasonic wave propagation is important for Structural Heath Monitoring and System Prognosis problems. In order to develop intelligent and adaptive structures with embedded damage detector and classifier mechanisms, detailed understanding of scattered wave fields due to anomaly in the structure is inevitably required. A detailed understanding of the problem demands a good modelling of the wave propagation in the problem geometry in virtual form. Therefore, efficient analytical, semi-analytical or numerical modelling techniques are required. In recent years a semi-analytical mesh-free technique called Distributed Point Source Method (DPSM) is being used for modelling various ultrasonic, electrostatic and electromagnetic wave field problems. In the conventional DPSM approach point sources are placed along the transducer faces, problem boundaries and interfaces to model incident and scattered fields. Every point source emits energy in all directions uniformly. Source strengths of these 360 degrees radiation sources are obtained by satisfying interface and boundary conditions of the problem. In conventional DPSM modelling approach it is assumed that the shadow zone does not require any special consideration. 360 degrees Radiation point sources should be capable of properly modelling shadow zones because all boundary and interface conditions are satisfied. In this paper it is investigated how good this assumption is by introducing the 'shadow zone' concept at the point source level and comparing the results generated by the conventional DPSM and by this modified approach where the conventional 360 degrees radiation point sources are replaced by the Controlled Space Radiation (CSR) sources.

  17. A combined analytical-experimental tensile test technique for brittle materials

    NASA Technical Reports Server (NTRS)

    Chu, M. L.; Scavuzzo, R. J.; Srivatsan, T. S.

    1992-01-01

    A semiconventional tensile test technique is developed for impact ices and other brittle materials. Accurate results have been obtained on ultimate strength and modulus of elasticity in a refrigerated ice test. It is noted that the technique can be used to determine the physical properties of impact ices accreted inside icing wind tunnels or other brittle materials.

  18. A New Project-Based Lab for Undergraduate Environmental and Analytical Chemistry

    ERIC Educational Resources Information Center

    Adami, Gianpiero

    2006-01-01

    A new project-based lab was developed for third year undergraduate chemistry students based on real world applications. The experience suggests that the total analytical procedure (TAP) project offers a stimulating alternative for delivering science skills and developing a greater interest for analytical chemistry and environmental sciences and…

  19. Multiview video codec based on KTA techniques

    NASA Astrophysics Data System (ADS)

    Seo, Jungdong; Kim, Donghyun; Ryu, Seungchul; Sohn, Kwanghoon

    2011-03-01

    Multi-view video coding (MVC) is a video coding standard developed by MPEG and VCEG for multi-view video. It showed average PSNR gain of 1.5dB compared with view-independent coding by H.264/AVC. However, because resolutions of multi-view video are getting higher for more realistic 3D effect, high performance video codec is needed. MVC adopted hierarchical B-picture structure and inter-view prediction as core techniques. The hierarchical B-picture structure removes the temporal redundancy, and the inter-view prediction reduces the inter-view redundancy by compensated prediction from the reconstructed neighboring views. Nevertheless, MVC has inherent limitation in coding efficiency, because it is based on H.264/AVC. To overcome the limit, an enhanced video codec for multi-view video based on Key Technology Area (KTA) is proposed. KTA is a high efficiency video codec by Video Coding Expert Group (VCEG), and it was carried out for coding efficiency beyond H.264/AVC. The KTA software showed better coding gain than H.264/AVC by using additional coding techniques. The techniques and the inter-view prediction are implemented into the proposed codec, which showed high coding gain compared with the view-independent coding result by KTA. The results presents that the inter-view prediction can achieve higher efficiency in a multi-view video codec based on a high performance video codec such as HEVC.

  20. Earth Science Data Analytics: Bridging Tools and Techniques with the Co-Analysis of Large, Heterogeneous Datasets

    NASA Technical Reports Server (NTRS)

    Kempler, Steve; Mathews, Tiffany

    2016-01-01

    The continuum of ever-evolving data management systems affords great opportunities to the enhancement of knowledge and facilitation of science research. To take advantage of these opportunities, it is essential to understand and develop methods that enable data relationships to be examined and the information to be manipulated. This presentation describes the efforts of the Earth Science Information Partners (ESIP) Federation Earth Science Data Analytics (ESDA) Cluster to understand, define, and facilitate the implementation of ESDA to advance science research. As a result of the void of Earth science data analytics publication material, the cluster has defined ESDA along with 10 goals to set the framework for a common understanding of tools and techniques that are available and still needed to support ESDA.

  1. Visualizing metal ions in cells: an overview of analytical techniques, approaches, and probes

    PubMed Central

    Dean, Kevin M.; Qin, Yan; Palmer, Amy E.

    2012-01-01

    Quantifying the amount and defining the location of metal ions in cells and organisms are critical steps in understanding metal homeostasis and how dyshomeostasis causes or is a consequence of disease. A number of recent advances have been made in the development and application of analytical methods to visualize metal ions in biological specimens. Here, we briefly summarize these advances before focusing in more depth on probes for examining transition metals in living cells with high spatial and temporal resolution using fluorescence microscopy. PMID:22521452

  2. Biomedical microelectromechanical systems (BioMEMS): Revolution in drug delivery and analytical techniques

    PubMed Central

    Jivani, Rishad R.; Lakhtaria, Gaurang J.; Patadiya, Dhaval D.; Patel, Laxman D.; Jivani, Nurrudin P.; Jhala, Bhagyesh P.

    2013-01-01

    Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures. PMID:26903763

  3. Approximate reanalysis based on the exact analytic expressions

    NASA Astrophysics Data System (ADS)

    Fuchs, Moshe B.; Maslovitz, Gilad

    1992-06-01

    Fuchs has recently given the exact analytic expressions of the inverse of the stiffness matrix, the nodal displacements, and the stress resultants in linear elastic structures composed of prismatic elements. For structures of constant geometry, the expressions are explicit in terms of the unimodal stiffnesses of the components of the structures. However, the expressions are intractable in their exact form due to their inordinate length. It all has to do with the number of statically determinate substructures embedded in common engineering structures. This paper describes some preliminary results obtained from approximate analysis models for the internal forces using truncated expressions that are similar in form to the exact analytic ones. The approach is illustrated with numerical examples.

  4. Field-flow fractionation as analytical technique for the characterization of dry yeast: correlation with wine fermentation activity.

    PubMed

    Sanz, Ramsés; Galceran, Ma Teresa; Puignou, Lluís

    2003-01-01

    Important oenological properties of wine depend on the winemaking yeast used in the fermentation process. There is considerable controversy about the quality of yeast, and a simple and cheap analytical methodology for quality control of yeast is needed. Gravitational field flow fractionation (GFFF) was used to characterize several commercial active dry wine yeasts from Saccharomyces cerevisiae and Saccharomyces bayanus and to assess the quality of the raw material before use. Laboratory-scale fermentations were performed using two different S. cerevisiae strains as inocula, and GFFF was used to follow the behavior of yeast cells during alcoholic fermentation. The viable/nonviable cell ratio was obtained by flow cytometry (FC) using propidium iodide as fluorescent dye. In each experiment, the amount of dry wine yeast to be used was calculated in order to provide the same quantity of viable cells. Kinetic studies of the fermentation process were performed controlling the density of the must, from 1.071 to 0.989 (20/20 density), and the total residual sugars, from 170 to 3 g/L. During the wine fermentation process, differences in the peak profiles obtained by GFFF between the two types of commercial yeasts that can be related with the unlike cell growth were observed. Moreover, the strains showed different fermentation kinetic profiles that could be correlated with the corresponding fractograms monitored by GFFF. These results allow optimism that sedimentation FFF techniques could be successfully used for quality assessment of the raw material and to predict yeast behavior during yeast-based bioprocesses such as wine production.

  5. Microfluidic paper-based analytical devices for potential use in quantitative and direct detection of disease biomarkers in clinical analysis.

    PubMed

    Lim, Wei Yin; Goh, Boon Tong; Khor, Sook Mei

    2017-08-15

    Clinicians, working in the health-care diagnostic systems of developing countries, currently face the challenges of rising costs, increased number of patient visits, and limited resources. A significant trend is using low-cost substrates to develop microfluidic devices for diagnostic purposes. Various fabrication techniques, materials, and detection methods have been explored to develop these devices. Microfluidic paper-based analytical devices (μPADs) have gained attention for sensing multiplex analytes, confirming diagnostic test results, rapid sample analysis, and reducing the volume of samples and analytical reagents. μPADs, which can provide accurate and reliable direct measurement without sample pretreatment, can reduce patient medical burden and yield rapid test results, aiding physicians in choosing appropriate treatment. The objectives of this review are to provide an overview of the strategies used for developing paper-based sensors with enhanced analytical performances and to discuss the current challenges, limitations, advantages, disadvantages, and future prospects of paper-based microfluidic platforms in clinical diagnostics. μPADs, with validated and justified analytical performances, can potentially improve the quality of life by providing inexpensive, rapid, portable, biodegradable, and reliable diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. From Data to Knowledge – Promising Analytical Tools and Techniques for Capture and Reuse of Corporate Knowledge and to Aid in the State Evaluation Process

    SciTech Connect

    Danielson, Gary R.; Augustenborg, Elsa C.; Beck, Andrew E.

    2010-10-29

    The IAEA is challenged with limited availability of human resources for inspection and data analysis while proliferation threats increase. PNNL has a variety of IT solutions and techniques (at varying levels of maturity and development) that take raw data closer to useful knowledge, thereby assisting with and standardizing the analytical processes. This paper highlights some PNNL tools and techniques which are applicable to the international safeguards community, including: • Intelligent in-situ triage of data prior to reliable transmission to an analysis center resulting in the transmission of smaller and more relevant data sets • Capture of expert knowledge in re-usable search strings tailored to specific mission outcomes • Image based searching fused with text based searching • Use of gaming to discover unexpected proliferation scenarios • Process modeling (e.g. Physical Model) as the basis for an information integration portal, which links to data storage locations along with analyst annotations, categorizations, geographic data, search strings and visualization outputs.

  7. COMPARISON OF ANALYTICAL TECHNIQUES FOR MEASURING HYDROCARBON EMISSIONS FROM THE MANUFACTURE OF FIBERGLASS-REINFORCED PLASTICS

    EPA Science Inventory

    The paper discusses several projects to measure hydrocarbon emissions associated with the manufacture of fiberglass-reinforced plastics. The main purpose of the projects was to evaluate pollution prevention techniques to reduce emissions by altering raw materials, application equ...

  8. COMPARISON OF ANALYTICAL TECHNIQUES FOR MEASURING HYDROCARBON EMISSIONS FROM THE MANUFACTURE OF FIBERGLASS-REINFORCED PLASTICS

    EPA Science Inventory

    The paper discusses several projects to measure hydrocarbon emissions associated with the manufacture of fiberglass-reinforced plastics. The main purpose of the projects was to evaluate pollution prevention techniques to reduce emissions by altering raw materials, application equ...

  9. Transcription factor-based biosensors enlightened by the analyte

    PubMed Central

    Fernandez-López, Raul; Ruiz, Raul; de la Cruz, Fernando; Moncalián, Gabriel

    2015-01-01

    Whole cell biosensors (WCBs) have multiple applications for environmental monitoring, detecting a wide range of pollutants. WCBs depend critically on the sensitivity and specificity of the transcription factor (TF) used to detect the analyte. We describe the mechanism of regulation and the structural and biochemical properties of TF families that are used, or could be used, for the development of environmental WCBs. Focusing on the chemical nature of the analyte, we review TFs that respond to aromatic compounds (XylS-AraC, XylR-NtrC, and LysR), metal ions (MerR, ArsR, DtxR, Fur, and NikR) or antibiotics (TetR and MarR). Analyzing the structural domains involved in DNA recognition, we highlight the similitudes in the DNA binding domains (DBDs) of these TF families. Opposite to DBDs, the wide range of analytes detected by TFs results in a diversity of structures at the effector binding domain. The modular architecture of TFs opens the possibility of engineering TFs with hybrid DNA and effector specificities. Yet, the lack of a crisp correlation between structural domains and specific functions makes this a challenging task. PMID:26191047

  10. Neutron capture radiography: a technique for isotopic labelling and analytical imaging with a few stable isotopes.

    PubMed

    Thellier, Michel; Ripoll, Camille

    2006-06-19

    NCR (neutron capture radiography) may be used successfully for the imaging of one of the stable isotopes of a few chemical elements (especially 6Li and 10B, possibly also 14N, 17O, and others) and for labelling experiments using these stable isotopes. Other physical techniques compete with NCR. However, NCR can remain extremely useful in a certain number of cases, because it is usually more easily done and is less expensive than the other techniques.

  11. Development of an analytical technique for the detection of alteration minerals formed in bentonite by reaction with alkaline solutions

    NASA Astrophysics Data System (ADS)

    Sakamoto, H.; Shibata, M.; Owada, H.; Kaneko, M.; Kuno, Y.; Asano, H.

    A multibarrier system consisting of cement-based backfill, structures and support materials, and a bentonite-based buffer material has been studied for the TRU waste disposal concept being developed in Japan, the aim being to restrict the migration of radionuclides. Concern regarding bentonite-based materials in this disposal environment relates to long-term alteration under hyper-alkaline conditions due to the presence of cementitious materials. In tests simulating the interaction between bentonite and cement, formation of secondary minerals due to alteration reactions under the conditions expected for geological disposal of TRU waste (equilibrated water with cement at low liquid/solid ratio) has not been observed, although alteration was observed under extremely hyper-alkaline conditions with high temperatures. This was considered to be due to the fact that analysis of C-S-H gel formed at the interface as a secondary mineral was difficult using XRD, because of its low crystallinity and low content. This paper describes an analytical technique for the characterization of C-S-H gel using a heavy liquid separation method which separates C-S-H gel from Kunigel V1 bentonite (bentonite produced in Japan) based on the difference in specific gravity between the crystalline minerals constituting Kunigel V1 and the secondary C-S-H gel. For development of C-S-H gel separation methods, simulated alteration samples were prepared by mixing 990 mg of unaltered Kunigel V1 and 10 mg of C-S-H gel synthesized using pure chemicals at a ratio of Ca/Si = 1.2. The simulated alteration samples were dispersed in bromoform-methanol mixtures with specific gravities ranging from 2.00 to 2.57 g/cm 3 and subjected to centrifuge separation to recover the light density fraction. Subsequent XRD analysis to identify the minerals was complemented by dissolution in 0.6 N hydrochloric acid to measure the Ca and Si contents. The primary peak (2 θ = 29.4°, Cu Kα) and secondary peaks (2 θ = 32.1

  12. multiplex gas chromatography: A novel analytical technique for future planetary studies

    NASA Technical Reports Server (NTRS)

    Valentin, J. R.; Carle, G. C.; Phillips, J. B.

    1986-01-01

    Determination of molecular species comprised of the biogenic elements in the atmospheres of planets and moons of the solar system is one the foremost requirements of the exobiologist studying chemical evolution and the origin of life. Multiplex chromatography is a technique where many samples are pseudo-randomly introduced to the chromatograph without regard to elution of preceding components. The resulting data are then reduced using mathematical techniques such as cross correlation or Fourier Transforms. To demonstrate the utility of this technique for future solar system exploration, chemical modulators were developed. Several advantages were realized from this technique in combination with these modulators: improvement in detection limits of several orders of magnitude, improvement in the analysis of complex mixtures by selectively modulating some of the components present in the sample, increase in the number of analyses that can be conducted in a given period of time, and reduction in the amount of expendables needed to run an analysis. In order to apply this technique in a real application, methane in ambient air was monitored continuously over a period of one week. By using ambient air as its own carrier all expendables beyond power were eliminated.

  13. Insight into Sam Francis' painting techniques through the analytical study of twenty-eight artworks made between 1946 and 1992

    NASA Astrophysics Data System (ADS)

    Defeyt, Catherine; Mazurek, Joy; Zebala, Aneta; Burchett-Lere, Debra

    2016-11-01

    The present paper proposes an overview of the painting materials experimented with over the years by Sam Francis, leading figure of the post-World War II American painting, through the analytical study of an extended number of paint samples supplied by the Sam Francis Foundation. In total, 279 samples taken from twenty-eight artworks made between 1946 and 1992, were analyzed by Raman, FTIR and Py-GC/MS techniques. The obtained results revealed the Francis' preference in terms of pigments, i.e., phthalocyanine blues and greens, and outlined unconventional combination of binder media.

  14. Analytical-scale separations of lanthanides : a review of techniques and fundamentals.

    SciTech Connect

    Nash, K. L.; Jensen, M. P.

    1999-10-27

    Separations chemistry is at the heart of most analytical procedures to determine the rare earth content of both man-made and naturally occurring materials. Such procedures are widely used in mineral exploration, fundamental geology and geochemistry, material science, and in the nuclear industry. Chromatographic methods that rely on aqueous solutions containing complexing agents sensitive to the lanthanide cationic radius and cation-exchange phase transfer reactions (using a variety of different solid media) have enjoyed the greatest success for these procedures. In this report, they will briefly summarize the most important methods for completing such analyses. they consider in some detail the basic aqueous (and two-phase) solution chemistry that accounts for separations that work well and offer explanations for why others are less successful.

  15. [Advance of studies on metabolic fingerprinting analytical techniques and data processing methods].

    PubMed

    Gao, Jian; Yang, Geng-liang; Yang, Hong-jun; Xu, Hai-yu; Li, Shao-jing

    2012-09-01

    Metabolomics is an emerging discipline subsequent to genomics, transcriptomics and proteomics, aiming for systematically studying the regularity of changes in metabolite to revealing organism's nature of movement and metabolism. It is especially important in modern pharmacological studies. Metabolic fingerprinting analysis is a method for metabolic analysis on high throughput of all metabolites, studying changes in drugs, organisms and endogenic metabolites caused by drugs and finding out related biomarkers to reflect dynamic changes inside organisms more directly and explain the mechanism of drugs and their effects on diseases. This essay summarizes some new metabolic fingerprint analytical methods and data processing methods used for metabolic fingerprint, elaborates their advantages and disadvantages and looks ahead to their combination with studies on traditional Chinese medicines, providing room for the development of new methods and new approaches for studies on complexity theory system of traditional Chinese medicines.

  16. Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques.

    PubMed

    Le Brech, Yann; Ghislain, Thierry; Leclerc, Sébastien; Bouroukba, Mohammed; Delmotte, Luc; Brosse, Nicolas; Snape, Colin; Chaimbault, Patrick; Dufour, Anthony

    2016-04-21

    Complementary analytical methods have been used to study the effect of potassium on the pyrolysis mechanisms of cellulose and lignocellulosic biomasses. Thermogravimetry, calorimetry, high-temperature (1) H NMR spectroscopy (in situ and real-time analysis of the fluid phase formed during pyrolysis), and water extraction of quenched char followed by size-exclusion chromatography coupled with mass spectrometry have been combined. Potassium impregnated in cellulose suppresses the formation of anhydrosugars, reduces the formation of mobile protons, and gives rise to a mainly exothermic signal. The evolution of mobile protons formed from K-impregnated cellulose has a very similar pattern to the evolution of the mass loss rate. This methodology has been also applied to analyze miscanthus, demineralized miscanthus, miscanthus re-impregnated with potassium after demineralization, raw oak, and Douglas fir. Hydrogen mobility and transfer are of high importance in the mechanisms of biomass pyrolysis.

  17. An analytic technique for statistically modeling random atomic clock errors in estimation

    NASA Technical Reports Server (NTRS)

    Fell, P. J.

    1981-01-01

    Minimum variance estimation requires that the statistics of random observation errors be modeled properly. If measurements are derived through the use of atomic frequency standards, then one source of error affecting the observable is random fluctuation in frequency. This is the case, for example, with range and integrated Doppler measurements from satellites of the Global Positioning and baseline determination for geodynamic applications. An analytic method is presented which approximates the statistics of this random process. The procedure starts with a model of the Allan variance for a particular oscillator and develops the statistics of range and integrated Doppler measurements. A series of five first order Markov processes is used to approximate the power spectral density obtained from the Allan variance.

  18. Modern analytical techniques in the assessment of the authenticity of Serbian honey.

    PubMed

    Milojković Opsenica, Dušanka; Lušić, Dražen; Tešić, Živoslav

    2015-12-01

    Food authenticity in a broader sense means fulfilling chemical and physical criteria prescribed by the proposed legislation. In the case of honey authenticity, two aspects are of major concern: the manufacturing process and the labelling of final products in terms of their geographical and botanical origin. A reliable assessment of honey authenticity has been a longterm preoccupation of chemists-analysts and it usually involves the use of several criteria and chemical markers, as well as a combination of analytical and statistical (chemometric) methods. This paper provides an overview of different criteria and modern methods for the assessment of honey authenticity in the case of a statistically significant number of authentic honey samples of several botanical types from various regions of Serbia.

  19. Advanced Analytical Techniques for the Measurement of Nanomaterials in Food and Agricultural Samples: A Review

    PubMed Central

    Bandyopadhyay, Susmita; Peralta-Videa, Jose R.; Gardea-Torresdey, Jorge L.

    2013-01-01

    Abstract Nanotechnology offers substantial prospects for the development of state-of-the-art products and applications for agriculture, water treatment, and food industry. Profuse use of nanoproducts will bring potential benefits to farmers, the food industry, and consumers, equally. However, after end-user applications, these products and residues will find their way into the environment. Therefore, discharged nanomaterials (NMs) need to be identified and quantified to determine their ecotoxicity and the levels of exposure. Detection and characterization of NMs and their residues in the environment, particularly in food and agricultural products, have been limited, as no single technique or method is suitable to identify and quantify NMs. In this review, we have discussed the available literature concerning detection, characterization, and measurement techniques for NMs in food and agricultural matrices, which include chromatography, flow field fractionation, electron microscopy, light scattering, and autofluorescence techniques, among others. PMID:23483065

  20. A Review on Microfluidic Paper-Based Analytical Devices for Glucose Detection

    PubMed Central

    Liu, Shuopeng; Su, Wenqiong; Ding, Xianting

    2016-01-01

    Glucose, as an essential substance directly involved in metabolic processes, is closely related to the occurrence of various diseases such as glucose metabolism disorders and islet cell carcinoma. Therefore, it is crucial to develop sensitive, accurate, rapid, and cost effective methods for frequent and convenient detections of glucose. Microfluidic Paper-based Analytical Devices (μPADs) not only satisfying the above requirements but also occupying the advantages of portability and minimal sample consumption, have exhibited great potential in the field of glucose detection. This article reviews and summarizes the most recent improvements in glucose detection in two aspects of colorimetric and electrochemical μPADs. The progressive techniques for fabricating channels on μPADs are also emphasized in this article. With the growth of diabetes and other glucose indication diseases in the underdeveloped and developing countries, low-cost and reliably commercial μPADs for glucose detection will be in unprecedentedly demand. PMID:27941634

  1. Analytical and experimental evaluation of techniques for the fabrication of thermoplastic hologram storage devices

    NASA Technical Reports Server (NTRS)

    Rogers, J. W.

    1975-01-01

    The results of an experimental investigation on recording information on thermoplastic are given. A description was given of a typical fabrication configuration, the recording sequence, and the samples which were examined. There are basically three configurations which can be used for the recording of information on thermoplastic. The most popular technique uses corona which furnishes free charge. The necessary energy for deformation is derived from a charge layer atop the thermoplastic. The other two techniques simply use a dc potential in place of the corona for deformation energy.

  2. Analytical method for the identification and assay of 12 phthalates in cosmetic products: application of the ISO 12787 international standard "Cosmetics-Analytical methods-Validation criteria for analytical results using chromatographic techniques".

    PubMed

    Gimeno, Pascal; Maggio, Annie-Françoise; Bousquet, Claudine; Quoirez, Audrey; Civade, Corinne; Bonnet, Pierre-Antoine

    2012-08-31

    Esters of phthalic acid, more commonly named phthalates, may be present in cosmetic products as ingredients or contaminants. Their presence as contaminant can be due to the manufacturing process, to raw materials used or to the migration of phthalates from packaging when plastic (polyvinyl chloride--PVC) is used. 8 phthalates (DBP, DEHP, BBP, DMEP, DnPP, DiPP, DPP, and DiBP), classified H360 or H361, are forbidden in cosmetics according to the European regulation on cosmetics 1223/2009. A GC/MS method was developed for the assay of 12 phthalates in cosmetics, including the 8 phthalates regulated. Analyses are carried out on a GC/MS system with electron impact ionization mode (EI). The separation of phthalates is obtained on a cross-linked 5%-phenyl/95%-dimethylpolysiloxane capillary column 30 m × 0.25 mm (i.d.) × 0.25 mm film thickness using a temperature gradient. Phthalate quantification is performed by external calibration using an internal standard. Validation elements obtained on standard solutions, highlight a satisfactory system conformity (resolution>1.5), a common quantification limit at 0.25 ng injected, an acceptable linearity between 0.5 μg mL⁻¹ and 5.0 μg mL⁻¹ as well as a precision and an accuracy in agreement with in-house specifications. Cosmetic samples ready for analytical injection are analyzed after a dilution in ethanol whereas more complex cosmetic matrices, like milks and creams, are assayed after a liquid/liquid extraction using ter-butyl methyl ether (TBME). Depending on the type of cosmetics analyzed, the common limits of quantification for the 12 phthalates were set at 0.5 or 2.5 μg g⁻¹. All samples were assayed using the analytical approach described in the ISO 12787 international standard "Cosmetics-Analytical methods-Validation criteria for analytical results using chromatographic techniques". This analytical protocol is particularly adapted when it is not possible to make reconstituted sample matrices. Copyright © 2012

  3. Classification of user interfaces for graph-based online analytical processing

    NASA Astrophysics Data System (ADS)

    Michaelis, James R.

    2016-05-01

    In the domain of business intelligence, user-oriented software for conducting multidimensional analysis via Online- Analytical Processing (OLAP) is now commonplace. In this setting, datasets commonly have well-defined sets of dimensions and measures around which analysis tasks can be conducted. However, many forms of data used in intelligence operations - deriving from social networks, online communications, and text corpora - will consist of graphs with varying forms of potential dimensional structure. Hence, enabling OLAP over such data collections requires explicit definition and extraction of supporting dimensions and measures. Further, as Graph OLAP remains an emerging technique, limited research has been done on its user interface requirements. Namely, on effective pairing of interface designs to different types of graph-derived dimensions and measures. This paper presents a novel technique for pairing of user interface designs to Graph OLAP datasets, rooted in Analytic Hierarchy Process (AHP) driven comparisons. Attributes of the classification strategy are encoded through an AHP ontology, developed in our alternate work and extended to support pairwise comparison of interfaces. Specifically, according to their ability, as perceived by Subject Matter Experts, to support dimensions and measures corresponding to Graph OLAP dataset attributes. To frame this discussion, a survey is provided both on existing variations of Graph OLAP, as well as existing interface designs previously applied in multidimensional analysis settings. Following this, a review of our AHP ontology is provided, along with a listing of corresponding dataset and interface attributes applicable toward SME recommendation structuring. A walkthrough of AHP-based recommendation encoding via the ontology-based approach is then provided. The paper concludes with a short summary of proposed future directions seen as essential for this research area.

  4. An uncovered XIII century icon: particular use of organic pigments and gilding techniques highlighted by analytical methods.

    PubMed

    Daveri, Alessia; Doherty, Brenda; Moretti, Patrizia; Grazia, Chiara; Romani, Aldo; Fiorin, Enrico; Brunetti, Brunetto Giovanni; Vagnini, Manuela

    2015-01-25

    The restoration of a panel painting depicting a Madonna and Child listed as an unknown Tuscan artist of the nineteenth century, permitted the hidden original version, a XIII century Medieval icon to be uncovered. It is discovery provided the opportunity for an extensive in situ campaign of non-invasive analytical investigations by portable imaging and spectroscopic techniques (infrared, X-ray fluorescence and diffraction, UV-Vis absorption and emission), followed by aimed micro-destructive investigations (Raman and SEM-EDS). This approach permitted characterization of the original ground and paint layers by complementary techniques. Furthermore, this protocol allowed supplementary particularities of great interest to be highlighted. Namely, numerous original gilding techniques have been accentuated in diverse areas and include the use of surrogate gold (disulphur tin), orpiment as a further false gold and an area with an original silver rich layer. Moreover, pigments including azurite mixed with indigo have been non-invasively identified. Micro-invasive analyses also allowed the diagnosis of organic colorants, namely, an animal anthraquinone lake, kermes and an unusual vegetal chalcone pigment, possibly safflower. The identification of the latter is extremely rare as a painting pigment and has been identified using an innovative adaption to surface enhanced Raman techniques on a cross-section. The resulting data contributes new hypotheses to the historic and artistic knowledge of materials and techniques utilized in XIII century icon paintings and ultimately provides scientific technical support of the recent restoration.

  5. An uncovered XIII century icon: Particular use of organic pigments and gilding techniques highlighted by analytical methods

    NASA Astrophysics Data System (ADS)

    Daveri, Alessia; Doherty, Brenda; Moretti, Patrizia; Grazia, Chiara; Romani, Aldo; Fiorin, Enrico; Brunetti, Brunetto Giovanni; Vagnini, Manuela

    2015-01-01

    The restoration of a panel painting depicting a Madonna and Child listed as an unknown Tuscan artist of the nineteenth century, permitted the hidden original version, a XIII century Medieval icon to be uncovered. It is discovery provided the opportunity for an extensive in situ campaign of non-invasive analytical investigations by portable imaging and spectroscopic techniques (infrared, X-ray fluorescence and diffraction, UV-Vis absorption and emission), followed by aimed micro-destructive investigations (Raman and SEM-EDS). This approach permitted characterization of the original ground and paint layers by complementary techniques. Furthermore, this protocol allowed supplementary particularities of great interest to be highlighted. Namely, numerous original gilding techniques have been accentuated in diverse areas and include the use of surrogate gold (disulphur tin), orpiment as a further false gold and an area with an original silver rich layer. Moreover, pigments including azurite mixed with indigo have been non-invasively identified. Micro-invasive analyses also allowed the diagnosis of organic colorants, namely, an animal anthraquinone lake, kermes and an unusual vegetal chalcone pigment, possibly safflower. The identification of the latter is extremely rare as a painting pigment and has been identified using an innovative adaption to surface enhanced Raman techniques on a cross-section. The resulting data contributes new hypotheses to the historic and artistic knowledge of materials and techniques utilized in XIII century icon paintings and ultimately provides scientific technical support of the recent restoration.

  6. Use of the Relaxometry Technique for Quantification of Paramagnetic Ions in Aqueous Solutions and a Comparison with Other Analytical Methods

    PubMed Central

    Burato, Juliana Soares da Silva; Silva Lobo, Carlos Manuel; Colnago, Luiz Alberto

    2016-01-01

    We have demonstrated that the relaxometry technique is very efficient to quantify paramagnetic ions during in situ electrolysis measurements. Therefore, the goal of this work was to validate the relaxometry technique in the determination of the concentration of the ions contained in electrolytic solutions, Cu2+, Ni2+, Cr3+, and Mn2+, and compare it with other analytical methods. Two different NMR spectrometers were used: a commercial spectrometer with a homogeneous magnetic field and a home-built unilateral sensor with an inhomogeneous magnetic field. Without pretreatment, manganese ions do not have absorption bands in the UV-Visible region, but it is possible to quantify them using relaxometry (the limit of quantification is close to 10−5 mol L−1). Therefore, since the technique does not require chemical indicators and is a cheap and robust method, it can be used as a replacement for some conventional quantification techniques. The relaxometry technique could be applied to evaluate the corrosion of metallic surfaces. PMID:27293437

  7. A fluorescent microsphere-based method for assay of multiple analytes in plasma.

    PubMed

    Bernhard, Oliver K; Mathias, Rommel A; Barnes, Thomas W; Simpson, Richard J

    2011-01-01

    Measurement of multiple analytes can provide increased sensitivity and specificity for the detection and management of disease. The enzyme-linked immunosorbent assay (ELISA) is currently the "gold standard" for protein quantification; however, individual assays for each analyte must be performed, placing demand on sample volume. On the contrary, multiplex assays using microsphere-based technologies allow for multiple analytes to be simultaneously assayed within a single sample. Here, we present a protocol for the preparation and development of a multiple-analyte assay in human plasma using the BioPlex 200 platform (Bio-Rad), which incorporates xMAP technology (Luminex).

  8. A genetic algorithm-based job scheduling model for big data analytics.

    PubMed

    Lu, Qinghua; Li, Shanshan; Zhang, Weishan; Zhang, Lei

    Big data analytics (BDA) applications are a new category of software applications that process large amounts of data using scalable parallel processing infrastructure to obtain hidden value. Hadoop is the most mature open-source big data analytics framework, which implements the MapReduce programming model to process big data with MapReduce jobs. Big data analytics jobs are often continuous and not mutually separated. The existing work mainly focuses on executing jobs in sequence, which are often inefficient and consume high energy. In this paper, we propose a genetic algorithm-based job scheduling model for big data analytics applications to improve the efficiency of big data analytics. To implement the job scheduling model, we leverage an estimation module to predict the performance of clusters when executing analytics jobs. We have evaluated the proposed job scheduling model in terms of feasibility and accuracy.

  9. The influence of surface chemistry on GSR particles: using XPS to complement SEM/EDS analytical techniques

    NASA Astrophysics Data System (ADS)

    Schwoeble, A. J.; Strohmeier, Brian R.; Piasecki, John D.

    2010-06-01

    Gunshot residue particles (GSR) were examined using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) to illustrate the size, shape, morphology, and elemental composition normally observed in particulate resulting from a discharged firearm. Determining the presence of lead (Pb), antimony (Sb), and barium (Ba), barring other elemental tags, fused together in a single particle with the correct morphology, is all that is required for the positive identification of GSR. X-ray photoelectron spectroscopy (XPS), however, can reveal more detailed information on surface chemistry than SEM/EDS. XPS is a highly surface-sensitive (<= ~10 nm), non-destructive, analytical technique that provides qualitative information for all elements except hydrogen and helium. Nanometer-scale sampling depth and its ability to provide unique chemical state information make XPS a potential technique for providing important knowledge on the surface chemistry of GSR that complements results obtained from SEM/EDS analysis.

  10. Diagnostics for the developing world: microfluidic paper-based analytical devices.

    PubMed

    Martinez, Andres W; Phillips, Scott T; Whitesides, George M; Carrilho, Emanuel

    2010-01-01

    Microfluidic paper-based analytical devices (microPADs) are a new class of point-of-care diagnostic devices that are inexpensive, easy to use, and designed specifically for use in developing countries. (To listen to a podcast about this feature, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html.).

  11. Development of a Quasi-Steady Flow Electrochemical Paper-Based Analytical Device.

    PubMed

    Adkins, Jaclyn A; Noviana, Eka; Henry, Charles S

    2016-11-01

    An electrochemical paper-based analytical device (ePAD) was developed for quasi-steady flow detection at microwire electrodes, for the first time. The device implements a fan shaped geometry connected to an analysis channel whereby solution is pulled from an inlet, through a channel, and into the steadily increasing capillary network of the fan. The network counteracts the decrease in solution flow rate associated with increasing viscosity within the channel, generating quasi-steady flow within the analysis channel. Microwire electrodes were embedded between two paper layers within the analysis channel, such that solution flow occurred on both sides of the wire electrodes. The quasi-steady flow ePAD increased the current by 2.5 times and 0.7 times from a saturated channel with no flow and from a single-layer paper device with flow, respectively. Amperometric detection was used for flow injection analysis (FIA) of multiple analytes at both Au and Pt microwire working electrodes, both of which provided similar sensitivity (ca. 0.2 mM(-1)) when normalized to the same standard. The two-layer paper devices provided a detection limit of 31 μM for p-aminophenol (PAP) using Pt electrodes and was also used to detect enzyme activity for the reaction of β-galactosidase with p-aminophenyl-galactopyranoside (PAPG). Measured enzyme kinetics provided similar Vmax (0.079 mM/min) and Km (0.36 mM) values as those found in the literature. This device shows great promise toward use in enzyme-linked immunosorbent assays or other analytical techniques where flow or washing steps are necessary. The developed sensor provides a simple and inexpensive device capable of performing multiple injection analysis with steady-flow and online detection that would normally require an external pump to perform.

  12. Analytical techniques for identification and study of organic matter in returned lunar samples

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.

    1974-01-01

    The results of geochemical research are reviewed. Emphasis is placed on the contribution of mass spectrometric data to the solution of specific structural problems. Information on the mass spectrometric behavior of compounds of geochemical interest is reviewed and currently available techniques of particular importance to geochemistry, such as gas chromatograph-mass spectrometer coupling, modern sample introduction methods, and computer application in high resolution mass spectrometry, receive particular attention.

  13. Sampling and analytical techniques for an interim survey in the South Carolina lowcountry

    Treesearch

    Richard L. Welch; Robert A. Cathey

    1976-01-01

    Remeasurement of 675 permanent sample locations in the South Carolina Lowcountry using modified sampling techniques showed that net growth of pine for the 6 years 1968-1974 was 637.0 million cubic feet while removals were slightly over 390.6 million cubic feet. In 1974, there were 1,533.5 million cubic feet of pine in the area with that portion in sawtimber size...

  14. Computational Diagnostic Techniques for Electromagnetic Scattering: Analytical Imaging, Near Fields, and Surface Currents

    NASA Technical Reports Server (NTRS)

    Hom, Kam W.; Talcott, Noel A., Jr.; Shaeffer, John

    1997-01-01

    This paper presents three techniques and the graphics implementations which can be used as diagnostic aides in the design and understanding of scattering structures: Imaging, near fields, and surface current displays. The imaging analysis is a new bistatic k space approach which has potential for much greater information than standard experimental approaches. The near field and current analysis are implementations of standard theory while the diagnostic graphics displays are implementations exploiting recent computer engineering work station graphics libraries.

  15. An analytical investigation of NO sub x control techniques for methanol fueled spark ignition engines

    NASA Technical Reports Server (NTRS)

    Browning, L. H.; Argenbright, L. A.

    1983-01-01

    A thermokinetic SI engine simulation was used to study the effects of simple nitrogen oxide control techniques on performance and emissions of a methanol fueled engine. As part of this simulation, a ring crevice storage model was formulated to predict UBF emissions. The study included spark retard, two methods of compression ratio increase and EGR. The study concludes that use of EGR in high turbulence, high compression engines will both maximize power and thermal efficiency while minimizing harmful exhaust pollutants.

  16. Multi analytical technique study of human bones from an archaeological discovery.

    PubMed

    Lachowicz, J I; Palomba, S; Meloni, P; Carboni, M; Sanna, G; Floris, R; Pusceddu, V; Sarigu, M

    2017-03-01

    In 1953, during the building restoration of San Michele church (Bono, Sardinia, 16th-19th Century), a high number of disarticulated skeletons were recovered. From a group of 412 hip bones, two of these, affected by several pathological lesions, were analysed. The two coxal bones can be referred to the same individual, an adult man. A multi-analytical study, started with the purpose of investigating the bone pathology, was extended to characterize the mineral components of a large representative set of bones from the same ossuary, all attributed to adult men who lived in the region four-two centuries ago. A quantitative ICP-AES analysis for Ca, Fe, Mg, Mn, Na, Pb and Zn was executed, and a chemometric investigation on the results was performed. This approach gave evidence of the effects of diagenesis, allowed some hypothesis of the incidence of the known dietary habits on bone composition, and completely differentiated the pathological bones from those of a normal population on the basis of the mineral composition. Moreover, porosity, crystallinity and FT-IR analysis were conducted on both non- and pathological sample. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Re-Paying Attention to Visitor Behavior: A Re-Analysis using Meta-Analytic Techniques.

    PubMed

    Castro, Yone; Botella, Juan; Asensio, Mikel

    2016-06-20

    The present study describes a meta-analytic review of museum visitors' behavior. Although there is a large number of visitor studies available, their cumulative importance has not been determined due to the lack of rigorous methods to determine common causes of visitors' behaviors. We analyzed Serrell's (1998) database of 110 studies, defining a number of variables that measure visitors' behaviors in exhibition spaces which exceeded the most typical and obvious ones. We defined four indexes of effect size and obtained their combined estimates: average time per feature [ATF● = 0.43 (0.49; 0.37)], percentage of diligent visitors [dv● = 30% (0.39; 0.23)], inverse of velocity [Iv● = 4.07 min/100m2 (4.55; 3.59)], and stops per feature [SF● = 0.35 (0.38; 0.33)], and we analyzed the role of relevant moderating variables. Key findings indicate, for example, that the visiting time for each display element relates to the size of the exhibition and its newness, and visitor walking speed is higher in large exhibit areas. The indexes obtained in this study can be understood as references to be used for comparison with new evaluations. They may help to predict people's behavior and appreciation of new exhibitions, identifying important problems in museum designs, and providing new research tools for this field.

  18. Mass Spectrometry as a Powerful Analytical Technique for the Structural Characterization of Synthesized and Natural Products

    NASA Astrophysics Data System (ADS)

    Es-Safi, Nour-Eddine; Essassi, El Mokhtar; Massoui, Mohamed; Banoub, Joseph

    Mass spectrometry is an important tool for the identification and structural elucidation of natural and synthesized compounds. Its high sensitivity and the possibility of coupling liquid chromatography with mass spectrometry detection make it a technique of choice for the investigation of complex mixtures like raw natural extracts. The mass spectrometer is a universal detector that can achieve very high sensitivity and provide information on the molecular mass. More detailed information can be subsequently obtained by resorting to collision-induced dissociation tandem mass spectrometry (CID-MS/MS). In this review, the application of mass spectrometric techniques for the identification of natural and synthetic compounds is presented. The gas-phase fragmentation patterns of a series of four natural flavonoid glycosides, three synthesized benzodiazepines and two synthesized quinoxalinone derivatives were investigated using electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry techniques. Exact accurate masses were measured using a modorate resolution quadrupole orthogonal time-of-flight QqTOF-MS/MS hybrid mass spectrometer instrument. Confirmation of the molecular masses and the chemical structures of the studied compounds were achieved by exploring the gas-phase breakdown routes of the ionized molecules. This was rationalized by conducting low-energy collision CID-MS/MS analyses (product ion- and precursor ion scans) using a conventional quadrupole hexapole-quadrupole (QhQ) tandem mass spectrometer.

  19. UPb ages of zircon rims: A new analytical method using the air-abrasion technique

    USGS Publications Warehouse

    Aleinikoff, J.N.; Winegarden, D.L.; Walter, M.

    1990-01-01

    We present a new technique for directly dating, by conventional techniques, the rims of zircons. Several circumstances, such as a xenocrystic or inherited component in igneous zircon and metamorphic overgrowths on igneous cores, can result in grains with physically distinct age components. Pneumatic abrasion has been previously shown by Krogh to remove overgrowths and damaged areas of zircon, leaving more resistant and isotopically less disturbed parts available for analysis. A new abrader design, which is capable of very gently grinding only tips and interfacial edges of even needle-like grains, permits easy collection of abraded material for dating. Five examples demonstrate the utility of the "dust-collecting" technique, including two studies that compare conventional, ion microprobe and abrader data. Common Pb may be strongly concentrated in the outermost zones of many zircons and this Pb is not easily removed by leaching (even in weak HF). Thus, the benefit of removing only the outermost zones (and avoiding mixing of age components) is somewhat compromised by the much higher common Pb contents which result in less precise age determinations. A very brief abrasion to remove the high common Pb zones prior to collection of material for dating is selected. ?? 1990.

  20. Analytical Modelling of the Effects of Different Gas Turbine Cooling Techniques on Engine Performance =

    NASA Astrophysics Data System (ADS)

    Uysal, Selcuk Can

    In this research, MATLAB SimulinkRTM was used to develop a cooled engine model for industrial gas turbines and aero-engines. The model consists of uncooled on-design, mean-line turbomachinery design and a cooled off-design analysis in order to evaluate the engine performance parameters by using operating conditions, polytropic efficiencies, material information and cooling system details. The cooling analysis algorithm involves a 2nd law analysis to calculate losses from the cooling technique applied. The model is used in a sensitivity analysis that evaluates the impacts of variations in metal Biot number, thermal barrier coating Biot number, film cooling effectiveness, internal cooling effectiveness and maximum allowable blade temperature on main engine performance parameters of aero and industrial gas turbine engines. The model is subsequently used to analyze the relative performance impact of employing Anti-Vortex Film Cooling holes (AVH) by means of data obtained for these holes by Detached Eddy Simulation-CFD Techniques that are valid for engine-like turbulence intensity conditions. Cooled blade configurations with AVH and other different external cooling techniques were used in a performance comparison study. (Abstract shortened by ProQuest.).

  1. Boron isotope determinations in waters and other geological materials: analytical techniques and inter-calibration of measurements.

    PubMed

    Tonarini, Sonia; Pennisi, Maddalena; Gonfiantini, Roberto

    2009-06-01

    The (11)B/(10)B ratio exhibits wide variations in nature; thus, boron isotopes have found numerous applications in geochemistry, hydrology, and environmental studies. The main analytical techniques used are as follows: positive thermal ionisation mass spectrometry is the most precise (about 0.2 per thousand of the boron isotope ratio), but requires complex and laborious sample preparation; negative thermal ionisation mass spectrometry is less precise (about 0.5 per thousand), but rapid and suitable for water samples, whereas total evaporation-NTIMS allows for identification of the precise boron isotope composition of marine carbonates. It is expected that multi-collection system inductively coupled plasma mass spectrometry (MC-ICPMS) will eventually combine high precision with simple analytical procedures. Secondary ion mass spectrometry and laser ablation (LA)-MC-ICPMS allow in situ determinations on solid samples, but require the availability of calibration materials which are chemically and mineralogically similar to samples. These features of boron isotope measurement techniques were confirmed by the results of the first inter-laboratory comparison of measurements, organised by the Istituto di Geoscienze e Georisorse in Pisa. Finally, two examples of boron isotope applications in groundwater investigations are reported.

  2. A three-dimensional finite-element thermal/mechanical analytical technique for high-performance traveling wave tubes

    NASA Technical Reports Server (NTRS)

    Bartos, Karen F.; Fite, E. Brian; Shalkhauser, Kurt A.; Sharp, G. Richard

    1991-01-01

    Current research in high-efficiency, high-performance traveling wave tubes (TWT's) has led to the development of novel thermal/ mechanical computer models for use with helical slow-wave structures. A three-dimensional, finite element computer model and analytical technique used to study the structural integrity and thermal operation of a high-efficiency, diamond-rod, K-band TWT designed for use in advanced space communications systems. This analysis focused on the slow-wave circuit in the radiofrequency section of the TWT, where an inherent localized heating problem existed and where failures were observed during earlier cold compression, or 'coining' fabrication technique that shows great potential for future TWT development efforts. For this analysis, a three-dimensional, finite element model was used along with MARC, a commercially available finite element code, to simulate the fabrication of a diamond-rod TWT. This analysis was conducted by using component and material specifications consistent with actual TWT fabrication and was verified against empirical data. The analysis is nonlinear owing to material plasticity introduced by the forming process and also to geometric nonlinearities presented by the component assembly configuration. The computer model was developed by using the high efficiency, K-band TWT design but is general enough to permit similar analyses to be performed on a wide variety of TWT designs and styles. The results of the TWT operating condition and structural failure mode analysis, as well as a comparison of analytical results to test data are presented.

  3. A three-dimensional finite-element thermal/mechanical analytical technique for high-performance traveling wave tubes

    NASA Technical Reports Server (NTRS)

    Shalkhauser, Kurt A.; Bartos, Karen F.; Fite, E. B.; Sharp, G. R.

    1992-01-01

    Current research in high-efficiency, high-performance traveling wave tubes (TWT's) has led to the development of novel thermal/mechanical computer models for use with helical slow-wave structures. A three-dimensional, finite element computer model and analytical technique used to study the structural integrity and thermal operation of a high-efficiency, diamond-rod, K-band TWT designed for use in advanced space communications systems. This analysis focused on the slow-wave circuit in the radiofrequency section of the TWT, where an inherent localized heating problem existed and where failures were observed during earlier cold compression, or 'coining' fabrication technique that shows great potential for future TWT development efforts. For this analysis, a three-dimensional, finite element model was used along with MARC, a commercially available finite element code, to simulate the fabrication of a diamond-rod TWT. This analysis was conducted by using component and material specifications consistent with actual TWT fabrication and was verified against empirical data. The analysis is nonlinear owing to material plasticity introduced by the forming process and also to geometric nonlinearities presented by the component assembly configuration. The computer model was developed by using the high efficiency, K-band TWT design but is general enough to permit similar analyses to be performed on a wide variety of TWT designs and styles. The results of the TWT operating condition and structural failure mode analysis, as well as a comparison of analytical results to test data are presented.

  4. Integrated analytical techniques with high sensitivity for studying brain translocation and potential impairment induced by intranasally instilled copper nanoparticles.

    PubMed

    Bai, Ru; Zhang, Lili; Liu, Ying; Li, Bai; Wang, Liming; Wang, Peng; Autrup, Herman; Beer, Christiane; Chen, Chunying

    2014-04-07

    Health impacts of inhalation exposure to engineered nanomaterials have attracted increasing attention. In this paper, integrated analytical techniques with high sensitivity were used to study the brain translocation and potential impairment induced by intranasally instilled copper nanoparticles (CuNPs). Mice were exposed to CuNPs in three doses (1, 10, 40 mg/kg bw). The body weight of mice decreased significantly in the 10 and 40 mg/kg group (p<0.05) but recovered slightly within exposure duration. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that CuNPs could enter the brain. Altered distribution of some important metal elements was observed by synchrotron radiation X-ray fluorescence (SRXRF). H&E staining and immunohistochemical analysis showed that CuNPs produced damages to nerve cells and astrocyte might be the one of the potential targets of CuNPs. The changes of neurotransmitter levels in different brain regions demonstrate that the dysfunction occurred in exposed groups. These data indicated that CuNPs could enter the brain after nasal inhalation and induced damages to the central nervous system (CNS). Integration of effective analytical techniques for systematic investigations is a promising direction to better understand the biological activities of nanomaterials. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Artificial Intelligence based technique for BTS placement

    NASA Astrophysics Data System (ADS)

    Alenoghena, C. O.; Emagbetere, J. O.; Aibinu, A. M.

    2013-12-01

    The increase of the base transceiver station (BTS) in most urban areas can be traced to the drive by network providers to meet demand for coverage and capacity. In traditional network planning, the final decision of BTS placement is taken by a team of radio planners, this decision is not fool proof against regulatory requirements. In this paper, an intelligent based algorithm for optimal BTS site placement has been proposed. The proposed technique takes into consideration neighbour and regulation considerations objectively while determining cell site. The application will lead to a quantitatively unbiased evaluated decision making process in BTS placement. An experimental data of a 2km by 3km territory was simulated for testing the new algorithm, results obtained show a 100% performance of the neighbour constrained algorithm in BTS placement optimization. Results on the application of GA with neighbourhood constraint indicate that the choices of location can be unbiased and optimization of facility placement for network design can be carried out.

  6. Analytical protocols based on LC-MS, GC-MS and CE-MS for nontargeted metabolomics of biological tissues.

    PubMed

    Naz, Shama; Moreira dos Santos, Délia Chaves; García, Antonia; Barbas, Coral

    2014-01-01

    Invasive, site-specific metabolite information could be better obtained from tissues. Hence, highly sensitive mass spectrometry-based metabolomics coupled with separation techniques are increasingly in demand in clinical research for tissue metabolomics application. Applying these techniques to nontargeted tissue metabolomics provides identification of distinct metabolites. These findings could help us to understand alterations at the molecular level, which can also be applied in clinical practice as screening markers for early disease diagnosis. However, tissues as solid and heterogeneous samples pose an additional analytical challenge that should be considered in obtaining broad, reproducible and representative analytical profiles. This manuscript summarizes the state of the art in tissue (human and animal) treatment (quenching, homogenization and extraction) for nontargeted metabolomics with mass spectrometry.

  7. Analytical technique to address terrorist threats by chemical weapons of mass destruction

    NASA Astrophysics Data System (ADS)

    Dempsey, Patrick M.

    1997-01-01

    Terrorism is no longer an issue without effect on the American mind. We now live with the same concerns and fears that have been commonplace in other developed and third world countries for a long time. Citizens of other countries have long lived with the specter of terrorism and now the U.S. needs to be concerned and prepared for terrorist activities.T he terrorist has the ability to cause great destructive effects by focusing their effort on unaware and unprepared civilian populations. Attacks can range from simple explosives to sophisticated nuclear, chemical and biological weapons. Intentional chemical releases of hazardous chemicals or chemical warfare agents pose a great threat because of their ready availability and/or ease of production, and their ability to cause widespread damage. As this battlefront changes from defined conflicts and enemies to unnamed terrorists, we must implement the proper analytical tools to provide a fast and efficient response. Each chemical uses in a terrorists weapon leaves behind a chemical signature that can be used to identify the materials involved and possibly lead investigators to the source and to those responsible. New tools to provide fast and accurate detection for battlefield chemical and biological agent attack are emerging. Gas chromatography/mass spectrometry (GC/MS) is one of these tools that has found increasing use by the military to respond to chemical agent attacks. As the technology becomes smaller and more portable, it can be used by law enforcement personnel to identify suspected terrorist releases and to help prepare the response; define contaminated areas for evacuation and safety concerns, identify the proper treatment of exposed or affected civilians, and suggest decontamination and cleanup procedures.

  8. Metabolomic analysis using porcine skin: a pilot study of analytical techniques.

    PubMed

    Wu, Julie; Fiehn, Oliver; Armstrong, April W

    2014-06-15

    Metabolic byproducts serve as indicators of the chemical processes and can provide valuable information on pathogenesis by measuring the amplified output. Standardized techniques for metabolome extraction of skin samples serve as a critical foundation to this field but have not been developed. We sought to determine the optimal cell lysage techniques for skin sample preparation and to compare GC-TOF-MS and UHPLC-QTOF-MS for metabolomic analysis. Using porcine skin samples, we pulverized the skin via various combinations of mechanical techniques for cell lysage. After extraction, the samples were subjected to GC-TOF-MS and/or UHPLC-QTOF-MS. Signal intensities from GC-TOF-MS analysis showed that ultrasonication (2.7x107) was most effective for cell lysage when compared to mortar-and-pestle (2.6x107), ball mill followed by ultrasonication (1.6x107), mortar-and-pestle followed by ultrasonication (1.4x107), and homogenization (trial 1: 8.4x106; trial 2: 1.6x107). Due to the similar signal intensities, ultrasonication and mortar-and-pestle were applied to additional samples and subjected to GC-TOF-MS and UHPLC-QTOF-MS. Ultrasonication yielded greater signal intensities than mortar-and-pestle for 92% of detected metabolites following GC-TOF-MS and for 68% of detected metabolites following UHPLC-QTOF-MS. Overall, ultrasonication is the preferred method for efficient cell lysage of skin tissue for both metabolomic platforms. With standardized sample preparation, metabolomic analysis of skin can serve as a powerful tool in elucidating underlying biological processes in dermatological conditions.

  9. An accelerated photo-magnetic imaging reconstruction algorithm based on an analytical forward solution and a fast Jacobian assembly method

    NASA Astrophysics Data System (ADS)

    Nouizi, F.; Erkol, H.; Luk, A.; Marks, M.; Unlu, M. B.; Gulsen, G.

    2016-10-01

    We previously introduced photo-magnetic imaging (PMI), an imaging technique that illuminates the medium under investigation with near-infrared light and measures the induced temperature increase using magnetic resonance thermometry (MRT). Using a multiphysics solver combining photon migration and heat diffusion, PMI models the spatiotemporal distribution of temperature variation and recovers high resolution optical absorption images using these temperature maps. In this paper, we present a new fast non-iterative reconstruction algorithm for PMI. This new algorithm uses analytic methods during the resolution of the forward problem and the assembly of the sensitivity matrix. We validate our new analytic-based algorithm with the first generation finite element method (FEM) based reconstruction algorithm previously developed by our team. The validation is performed using, first synthetic data and afterwards, real MRT measured temperature maps. Our new method accelerates the reconstruction process 30-fold when compared to a single iteration of the FEM-based algorithm.

  10. A polarization-based Thomson scattering technique for burning plasmas

    NASA Astrophysics Data System (ADS)

    Parke, E.; Mirnov, V. V.; Den Hartog, D. J.

    2014-02-01

    The traditional Thomson scattering diagnostic is based on measurement of the wavelength spectrum of scattered light, where electron temperature measurements are inferred from thermal broadening of the spectrum. At sufficiently high temperatures, especially those predicted for ITER and other burning plasmas, relativistic effects cause a change in the degree of polarization (P) of the scattered light; for fully polarized incident laser light, the scattered light becomes partially polarized. The resulting reduction of polarization is temperature dependent and has been proposed by other authors as a potential alternative to the traditional spectral decomposition technique. Following the previously developed Stokes vector approach, we analytically calculate the degree of polarization for incoherent Thomson scattering. For the first time, we obtain exact results valid for the full range of incident laser polarization states, scattering angles, and electron temperatures. While previous work focused only on linear polarization, we show that circularly polarized incident light optimizes the degree of depolarization for a wide range of temperatures relevant to burning plasmas. We discuss the feasibility of a polarization based Thomson scattering diagnostic for ITER-like plasmas with both linearly and circularly polarized light and compare to the traditional technique.

  11. Comparison of analytical techniques for detection of geosmin and 2-methylisoborneol in aqueous samples.

    PubMed

    Hurlburt, Barry; Lloyd, Steven W; Grimm, Casey C

    2009-09-01

    Geosmin and 2-methylisoborneol are secondary metabolites expressed by a variety of organisms that are responsible for off-flavors in public water supplies, aquaculture, and a host of other important products. Hence, there is continuing research into the causes for their expression and methods to mitigate it, which require sensitive and accurate detection methods. In recent years, several new techniques for collecting and concentrating volatile and semi-volatile compounds have been automated and commercialized, making them available for use in most laboratories. In this study, we compared solid-phase microextraction (SPME) and membrane-assisted solvent extraction (MASE) for the detection of 2-methylisoborneol and geosmin in aqueous samples. SPME is the most sensitive of these techniques with a limit of detection of 25 parts-per-trillion for 2-methylisoborneol and 10 parts-per-trillion for geosmin but with a large relative standard deviation. MASE is less sensitive, but provides a greater level of precision, as well as the ability for multiple injections from the same sample.

  12. Studies of ferroelectric heterostructure thin films and interfaces via in situ analytical techniques.

    SciTech Connect

    Auciello, O.; Dhote, A.; Gao, Y.; Gruen, D. M.; Im, J.; Irene, E. A.; Krauss, A. R.; Mueller, A. H.; Ramesh, R.

    1999-08-30

    The science and technology of ferroelectric thin films has experienced an explosive development during the last ten years. Low-density non-volatile ferroelectric random access memories (NVFRAMs) are now incorporated in commercial products such as ''smart cards'', while high permittivity capacitors are incorporated in cellular phones. However, substantial work is still needed to develop materials integration strategies for high-density memories. We have demonstrated that the implementation of complementary in situ characterization techniques is critical to understand film growth and interface processes, which play critical roles in film microstructure and properties. We are using uniquely integrated time of flight ion scattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry (SE) techniques to perform in situ, real-time studies of film growth processes in the high background gas pressure required to growth ferroelectric thin films. TOF-ISARS provides information on surface processes, while SE permits the investigation of buried interfaces as they are being formed. Recent studies on SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub x}Sr{sub 1{minus}x}TiO{sub 3} (BST) film growth and interface processes are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    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?

  14. Fluorescence assay based on preconcentration by a self-ordered ring using berberine as a model analyte.

    PubMed

    Liu, Ying; Huang, Cheng Zhi; Li, Yuan Fang

    2002-11-01

    A novel assay for trace amounts of fluorescent analytes is proposed based on the assembly of a self-ordered ring (SOR) through capillary flow in a sessile droplet on a glass slide support. After solvent evaporation of the sessile droplet containing a fluorescent analyte on a hydrophobic-treated glass slide, an outward capillary flow of the solvent from the interior of the droplet occurs. The resultant outward capillary flow then carries the analyte to the perimeter of the droplet spot where the analyte deposits and forms a fluorescent SOR. For the model analyte of berberine, SORs with outer diameter less than 1.2 mm and ring belt width less than 19 microm can be obtained depending on the droplet volume of the berberine solution. Data analysis for the digitally imaged SOR by using a CCD camera showed that the berberine molecules across the SOR belt section follow a Gaussian distribution, and the maximum fluorescent intensity (Imax) was found to be proportional to berberine content at the femtomole level. With the proposed technique, the content in tablets and the average excretion rates of berberine through human urine after oral administration could be satisfactorily monitored.

  15. Enabling big geoscience data analytics with a cloud-based, MapReduce-enabled and service-oriented workflow framework.

    PubMed

    Li, Zhenlong; Yang, Chaowei; Jin, Baoxuan; Yu, Manzhu; Liu, Kai; Sun, Min; Zhan, Matthew

    2015-01-01

    Geoscience observations and model simulations are generating vast amounts of multi-dimensional data. Effectively analyzing these data are essential for geoscience studies. However, the tasks are challenging for geoscientists because processing the massive amount of data is both computing and data intensive in that data analytics requires complex procedures and multiple tools. To tackle these challenges, a scientific workflow framework is proposed for big geoscience data analytics. In this framework techniques are proposed by leveraging cloud computing, MapReduce, and Service Oriented Architecture (SOA). Specifically, HBase is adopted for storing and managing big geoscience data across distributed computers. MapReduce-based algorithm framework is developed to support parallel processing of geoscience data. And service-oriented workflow architecture is built for supporting on-demand complex data analytics in the cloud environment. A proof-of-concept prototype tests the performance of the framework. Results show that this innovative framework significantly improves the efficiency of big geoscience data analytics by reducing the data processing time as well as simplifying data analytical procedures for geoscientists.

  16. Enabling Big Geoscience Data Analytics with a Cloud-Based, MapReduce-Enabled and Service-Oriented Workflow Framework

    PubMed Central

    Li, Zhenlong; Yang, Chaowei; Jin, Baoxuan; Yu, Manzhu; Liu, Kai; Sun, Min; Zhan, Matthew

    2015-01-01

    Geoscience observations and model simulations are generating vast amounts of multi-dimensional data. Effectively analyzing these data are essential for geoscience studies. However, the tasks are challenging for geoscientists because processing the massive amount of data is both computing and data intensive in that data analytics requires complex procedures and multiple tools. To tackle these challenges, a scientific workflow framework is proposed for big geoscience data analytics. In this framework techniques are proposed by leveraging cloud computing, MapReduce, and Service Oriented Architecture (SOA). Specifically, HBase is adopted for storing and managing big geoscience data across distributed computers. MapReduce-based algorithm framework is developed to support parallel processing of geoscience data. And service-oriented workflow architecture is built for supporting on-demand complex data analytics in the cloud environment. A proof-of-concept prototype tests the performance of the framework. Results show that this innovative framework significantly improves the efficiency of big geoscience data analytics by reducing the data processing time as well as simplifying data analytical procedures for geoscientists. PMID:25742012

  17. A quality control technique based on UV-VIS absorption spectroscopy for tequila distillery factories

    NASA Astrophysics Data System (ADS)

    Barbosa Garcia, O.; Ramos Ortiz, G.; Maldonado, J. L.; Pichardo Molina, J.; Meneses Nava, M. A.; Landgrave, Enrique; Cervantes, M. J.

    2006-02-01

    A low cost technique based on the UV-VIS absorption spectroscopy is presented for the quality control of the spirit drink known as tequila. It is shown that such spectra offer enough information to discriminate a given spirit drink from a group of bottled commercial tequilas. The technique was applied to white tequilas. Contrary to the reference analytic methods, such as chromatography, for this technique neither special personal training nor sophisticated instrumentations is required. By using hand-held instrumentation this technique can be applied in situ during the production process.

  18. Active alkaline traps to determine acidic-gas ratios in volcanic plumes: Sampling techniques and analytical methods

    NASA Astrophysics Data System (ADS)

    Wittmer, J.; Bobrowski, N.; Liotta, M.; Giuffrida, G.; Calabrese, S.; Platt, U.

    2014-07-01

    In situ measurements have been the basis for monitoring volcanic gas emissions for many years and—being complemented by remote sensing techniques—still play an important role to date. Concerning in situ techniques for sampling a dilute plume, an increase in accuracy and a reduction of detection limits are still necessary for most gases (e.g., CO2, SO2, HCl, HF, HBr, HI). In this work, the Raschig-Tube technique (RT) is modified and utilized for application on volcanic plumes. The theoretical and experimental absorption properties of the RT and the Drechsel bottle (DB) setups are characterized and both are applied simultaneously to the well-established Filter packs technique (FP) in the field (on Stromboli Island and Mount Etna). The comparison points out that FPs are the most practical to apply but the results are error-prone compared to RT and DB, whereas the RT results in up to 13 times higher analyte concentrations than the DB in the same sampling time. An optimization of the analytical procedure, including sample pretreatment and analysis by titration, Ion Chromatography, and Inductively Coupled Plasma Mass Spectrometry, led to a comprehensive data set covering a wide range of compounds. In particular, less abundant species were quantified more accurately and iodine was detected for the first time in Stromboli's plume. Simultaneously applying Multiaxis Differential Optical Absorption Spectroscopy (MAX-DOAS) the chemical transformation of emitted bromide into bromine monoxide (BrO) from Stromboli and Etna was determined to 3-6% and 7%, respectively, within less than 5 min after the gas release from the active vents.

  19. Predicting oil quality from sidewall cores using PFID, TEC, and NIR analytical techniques in sandstone reservoirs, Offshore Cameroon

    SciTech Connect

    Bement, W.O.; McNeil, R.I.; Lippincott, R.G.

    1996-08-01

    Cameroon reservoirs contain oil and gas that have migrated vertically from deeper buried thermally mature marine shales. Several shallow reservoirs also contain biogenic gas. Generally, lower gravity oils found in the shallow reservoirs have undergone various degrees of biodegradation. Deeper accumulations are higher gravity {open_quote}primary{close_quote} oils. The biodegraded oils are characterized by lower gravities, higher acid numbers, higher sulfur contents, and higher viscosities than their non-biodegraded counterparts. Oil quality (API gravity and acid number) has a significant impact on the development economics. It is important to obtain as much geochemical information as possible from the limited volume of oil contained in conventional sidewall samples because borehole conditions often preclude the possibility of running a wireline test tool (the MDT) to obtain a fluid sample. An analytical program of PFID (Pyrolysis Flame Ionization Detection), TEC (Thermal Extraction Chromatography) and NIR (Near Infra-Red spectroscopy) was conducted on a set of {open_quote}calibration{close_quote} oils and the data were used to develop both empirical and quantitative predictive criteria for estimating crude oil properties of gravity, acid number, sulfur content, and viscosity. Sidewall samples provide sufficient material for these micro-analytical techniques. The individual sidewalls were split for geochemical analysis with the remaining material available for petrographic analysis. The PFID and TEC techniques were run on the {open_quote}rock{close_quote} sample containing the oil. For the NIR technique, the oil was extracted from the sample with an organic solvent and the extract evaluated. Results will be presented for sidewall core samples obtained from four oil sands encountered during a two well exploratory program.

  20. New Insights into Amino Acid Preservation in the Early Oceans Using Modern Analytical Techniques

    NASA Technical Reports Server (NTRS)

    Parker, Eric T.; Brinton, Karen L.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.; Bada, Jeffrey L.

    2015-01-01

    Protein- and non-protein-amino acids likely occupied the oceans at the time of the origin and evolution of life. Primordial soup-, hydrothermal vent-, and meteoritic-processes likely contributed to this early chemical inventory. Prebiotic synthesis and carbonaceous meteorite studies suggest that non-protein amino acids were likely more abundant than their protein-counterparts. Amino acid preservation before abiotic and biotic destruction is key to biomarker availability in paleoenvironments and remains an important uncertainty. To constrain primitive amino acid lifetimes, a 1992 archived seawater/beach sand mixture was spiked with D,L-alanine, D,L-valine (Val), alpha-aminoisobutyric acid (alpha-AIB), D,L-isovaline (Iva), and glycine (Gly). Analysis by high performance liquid chromatography with fluorescence detection (HPLC-FD) showed that only D-Val and non-protein amino acids were abundant after 2250 days. The mixture was re-analyzed in 2012 using HPLC-FD and a triple quadrupole mass spectrometer (QqQ-MS). The analytical results 20 years after the inception of the experiment were strikingly similar to those after 2250 days. To confirm that viable microorganisms were still present, the mixture was re-spiked with Gly in 2012. Aliquots were collected immediately after spiking, and at 5- and 9-month intervals thereafter. Final HPLC-FD/QqQ-MS analyses were performed in 2014. The 2014 analyses revealed that only alpha-AIB, D,L-Iva, and D-Val remained abundant. The disappearance of Gly indicated that microorganisms still lived in the mixture and were capable of consuming protein amino acids. These findings demonstrate that non-protein amino acids are minimally impacted by biological degradation and thus have very long lifetimes under these conditions. Primitive non-protein amino acids from terrestrial synthesis, or meteorite in-fall, likely experienced great-er preservation than protein amino acids in paleo-oceanic environments. Such robust molecules may have reached a

  1. New Insights into Amino Acid Preservation in the Early Oceans using Modern Analytical Techniques

    NASA Astrophysics Data System (ADS)

    Parker, E. T.; Brinton, K. L.; Burton, A. S.; Glavin, D. P.; Dworkin, J. P.; Bada, J.

    2015-12-01

    Protein- and non-protein-amino acids likely occupied the oceans at the time of the origin and evolution of life. Primordial soup-, hydrothermal vent-, and meteoritic-processes likely contributed to this early chemical inventory. Prebiotic synthesis and carbonaceous meteorite studies suggest that non-protein amino acids were likely more abundant than their protein-counterparts. Amino acid preservation before abiotic and biotic destruction is key to biomarker availability in paleoenvironments and remains an important uncertainty. To constrain primitive amino acid lifetimes, a 1992 archived seawater/beach sand mixture was spiked with D,L-alanine, D,L-valine (Val), α-aminoisobutyric acid (α-AIB), D,L-isovaline (Iva), and glycine (Gly). Analysis by high performance liquid chromatography with fluorescence detection (HPLC-FD) showed that only D-Val and non-protein amino acids were abundant after 2250 days. The mixture was re-analyzed in 2012 using HPLC-FD and a triple quadrupole mass spectrometer (QqQ-MS). The analytical results 20 years after the inception of the experiment were strikingly similar to those after 2250 days. To confirm that viable microorganisms were still present, the mixture was re-spiked with Gly in 2012. Aliquots were collected immediately after spiking, and at 5- and 9-month intervals thereafter. Final HPLC-FD/QqQ-MS analyses were performed in 2014. The 2014 analyses revealed that only α-AIB, D,L-Iva, and D-Val remained abundant. The disappearance of Gly indicated that microorganisms still lived in the mixture and were capable of consuming protein amino acids. These findings demonstrate that non-protein amino acids are minimally impacted by biological degradation and thus have very long lifetimes under these conditions. Primitive non-protein amino acids from terrestrial synthesis, or meteorite in-fall, likely experienced greater preservation than protein amino acids in paleo-oceanic environments. Such robust molecules may have reached a steady

  2. Analytical techniques for estimation of heavy metals in soil ecosystem: a tabulated review.

    PubMed

    Soodan, Rajneet Kour; Pakade, Yogesh B; Nagpal, Avinash; Katnoria, Jatinder Kaur

    2014-07-01

    Soil, an important environmental medium, is exposed to a number of pollutants including toxic heavy metals by various natural and anthropogenic activities. Consequently heavy metal contaminated soil has the potential to pose severe health risks and hazards to humans as well as other living creatures of the ecosystem through various routes of exposure such as direct ingestion, contaminated drinking ground water, food crops, contact with contaminated soil and through food chain. Therefore, it is mandatory to explore various techniques that could efficiently determine the occurrence of heavy metals in soil. A number of methods have been developed by several regulatory agencies and private laboratories and are applied routinely for the quantification and monitoring of soil matrices. The present review is an initiative to summarize the work on pollution levels of soil ecosystem and thus pertains to various extraction and quantification procedures used worldwide to analyze heavy metals in soil.

  3. A comparison of smooth specimen and analytical simulation techniques for notched members at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Martin, J. F.

    1985-01-01

    Experimental strain measurements have been made at the highly strained regions on notched plate specimens that were made of Hastelloy X. Tests were performed at temperatures up to 1,600 F. Variable load patterns were chosen so as to produce plastic and creep strains. Were appropriate, notch root stresses were experimentally estimated by subjecting a smooth specimen to the measured notch root strains. The results of three analysis techniques are presented and compared to the experimental data. The most accurate results were obtained from an analysis procedure that used a smooth specimen and the Neuber relation to simulate the notch root stress-strain response. When a generalized constitutive relation was used with the Neuber relation, good results were also obtained, however, these results were not as accurate as those obtained when the smooth specimen was used directly. Finally, a general finite element program, ANYSIS, was used which resulted in acceptable solutions, but, these were the least accurate predictions.

  4. Development of analytical techniques to study H2s poisoning of PEMFCs and components

    SciTech Connect

    Brosha, Eric L; Rockward, Tommy; Uribe, Francisco A; Garzon, Fernando H

    2008-01-01

    Polymer electrolyte membrane fuel cells are sensitive to impurities that may be present in either the oxidizer or fuel. H{sub 2}S, even at the ppb level, will have a dramatic and adverse affect on fuel cell performance. Not only is it important to know a particular material's affinity to adsorb H{sub 2}S, when considering materials for PEMFC applications, issues such as permeation and crossover rates also become extremely important Several experimental methods have been developed to quantify H{sub 2}S adsorption onto surfaces and to quantify H{sub 2}S permeation through Nafion(reg.) membranes using readily available and inexpensive Ag/AgS ion probes. In addition to calculating the H{sub 2}S uptake on commonly used XC-72 carbon supports and PtlXC-72 catalysts, the H{sub 2}S permeability through dry and humidified Nafion(reg.) PEMFC membranes was also studied using these specialized techniques. In each ion probe experiment performed, a sulfide anti-oxidant buffer solution was used to trap and concentrate trace quantities of H{sub 2}S during the course of the measurement. Crossover experiments were conducted for up to 24 hours in order to achieve sulfide ion concentrations high enough to be precisely determined by subsequent titration with Pb(NO{sub 3}){sub 2}. By using these techniques, we have confirmed H{sub 2}S crossover in Nafion(reg.) membranes and have calculated preliminary rates of H{sub 2}S crossover.

  5. The role of VTIQ as a new tissue strain analytics measurement technique in testicular lesions.

    PubMed

    Trottmann, M; Marcon, J; D'Anastasi, M; Karl, A; Stief, C G; Reiser, M; Clevert, D A

    2014-01-01

    Virtual touch tissue imaging quantification (VTIQ) is a newly developed technique for the sonographic quantification of tissue elasticity. It has been used in the assessment of breast lesions. The purpose of this study was to determine the diagnostic performance of VTIQ in indeterminate testicular lesions. Twenty patients with known testicular pathology underwent conventional B-mode sonography with additional VTIQ of the testicular lesions using a Siemens Acuson S2000™ and S3000™ (Siemens Medical Solutions, Mountain View, CA, USA) system. Tissue mechanical properties were analysed in the VTIQ examination. The pathologic diagnosis was established after surgery or in the follow-up examination for suspected benign lesions. Over 36 months, 22 focal testicular lesions (median lesion size, 18 mm; range, 4-36 mm in 20 patients (median age, 43 years; range, 22-81 years) were examined. Lesions were hyperechoic (n = 1), hypoechoic (n = 14), isoechoic (n = 1), of mixed echogenicity (n = 3) or anechoic (n = 3). Histological examination showed one benign lesion (6.25%) with a mean size of 7 mm and 15 malignant lesions (93.75%) with a mean size of 20 mm. Mean shear wave velocity for normal testicular tissue was 1.17 m/s. No shear wave velocity could be measured in cystic lesions. The rest of the benign lesions showed a mean shear wave velocity of 2.37 m/s. The value of the shear wave velocity in germ cell tumours showed a mean shear wave velocity of 1.94 m/s and for seminoma it showed a mean shear wave velocity of 2.42 m/s. VTIQ is a reliable new method for measuring qualitative and quantitative stiffness of testicular lesions and tissue. The qualitative shear-wave elastography features were highly reproducible and showed good diagnostic performance in unclear testicular lesions. The VTIQ technique is also useful in assessing small testicular nodules and pseudolesions.

  6. An Experiential Research-Focused Approach: Implementation in a Nonlaboratory-Based Graduate-Level Analytical Chemistry Course

    ERIC Educational Resources Information Center

    Toh, Chee-Seng

    2007-01-01

    A project is described which incorporates nonlaboratory research skills in a graduate level course on analytical chemistry. This project will help students to grasp the basic principles and concepts of modern analytical techniques and also help them develop relevant research skills in analytical chemistry.

  7. An Experiential Research-Focused Approach: Implementation in a Nonlaboratory-Based Graduate-Level Analytical Chemistry Course

    ERIC Educational Resources Information Center

    Toh, Chee-Seng

    2007-01-01

    A project is described which incorporates nonlaboratory research skills in a graduate level course on analytical chemistry. This project will help students to grasp the basic principles and concepts of modern analytical techniques and also help them develop relevant research skills in analytical chemistry.

  8. Integration of Environmental Analytical Chemistry with Environmental Law: The Development of a Problem-Based Laboratory.

    ERIC Educational Resources Information Center

    Cancilla, Devon A.

    2001-01-01

    Introduces an undergraduate level problem-based analytical chemistry laboratory course integrated with an environmental law course. Aims to develop an understanding among students on the use of environmental indicators for environmental evaluation. (Contains 30 references.) (YDS)

  9. Integration of Environmental Analytical Chemistry with Environmental Law: The Development of a Problem-Based Laboratory.

    ERIC Educational Resources Information Center

    Cancilla, Devon A.

    2001-01-01

    Introduces an undergraduate level problem-based analytical chemistry laboratory course integrated with an environmental law course. Aims to develop an understanding among students on the use of environmental indicators for environmental evaluation. (Contains 30 references.) (YDS)

  10. Behavior-Based Budget Management Using Predictive Analytics

    SciTech Connect

    Troy Hiltbrand

    2013-03-01

    Historically, the mechanisms to perform forecasting have primarily used two common factors as a basis for future predictions: time and money. While time and money are very important aspects of determining future budgetary spend patterns, organizations represent a complex system of unique individuals with a myriad of associated behaviors and all of these behaviors have bearing on how budget is utilized. When looking to forecasted budgets, it becomes a guessing game about how budget managers will behave under a given set of conditions. This becomes relatively messy when human nature is introduced, as different managers will react very differently under similar circumstances. While one manager becomes ultra conservative during periods of financial austerity, another might be un-phased and continue to spend as they have in the past. Both might revert into a state of budgetary protectionism masking what is truly happening at a budget holder level, in order to keep as much budget and influence as possible while at the same time sacrificing the greater good of the organization. To more accurately predict future outcomes, the models should consider both time and money and other behavioral patterns that have been observed across the organization. The field of predictive analytics is poised to provide the tools and methodologies needed for organizations to do just this: capture and leverage behaviors of the past to predict the future.

  11. Web-Based Visual Analytics for Social Media

    SciTech Connect

    Best, Daniel M.; Bruce, Joseph R.; Dowson, Scott T.; Love, Oriana J.; McGrath, Liam R.

    2012-05-20

    Social media provides a rich source of data that reflects current trends and public opinion on a multitude of topics. The data can be harvested from Twitter, Facebook, Blogs, and other social applications. The high rate of adoption of social media has created a domain that has an ever expanding volume of data that make it difficult to use the raw data for analysis. Information visual analytics is key in drawing out features of interest in social media. The Scalable Reasoning System is an application that couples a back end server performing analysis algorithms and an intuitive front end visualization to allow for investigation. We provide a componentized system that can be rapidly adapted to customer needs such that the information they are most interested in is brought to their attention through the application. To this end, we have developed a social media application for use by emergency operations for the city of Seattle to show current weather and traffic trends which is important for their tasks.

  12. Monsoon Forecasting based on Imbalanced Classification Techniques

    NASA Astrophysics Data System (ADS)

    Ribera, Pedro; Troncoso, Alicia; Asencio-Cortes, Gualberto; Vega, Inmaculada; Gallego, David

    2017-04-01

    Monsoonal systems are quasiperiodic processes of the climatic system that control seasonal precipitation over different regions of the world. The Western North Pacific Summer Monsoon (WNPSM) is one of those monsoons and it is known to have a great impact both over the global climate and over the total precipitation of very densely populated areas. The interannual variability of the WNPSM along the last 50-60 years has been related to different climatic indices such as El Niño, El Niño Modoki, the Indian Ocean Dipole or the Pacific Decadal Oscillation. Recently, a new and longer series characterizing the monthly evolution of the WNPSM, the WNP Directional Index (WNPDI), has been developed, extending its previous length from about 50 years to more than 100 years (1900-2007). Imbalanced classification techniques have been applied to the WNPDI in order to check the capability of traditional climate indices to capture and forecast the evolution of the WNPSM. The problem of forecasting has been transformed into a binary classification problem, in which the positive class represents the occurrence of an extreme monsoon event. Given that the number of extreme monsoons is much lower than the number of non-extreme monsoons, the resultant classification problem is highly imbalanced. The complete dataset is composed of 1296 instances, where only 71 (5.47%) samples correspond to extreme monsoons. Twenty predictor variables based on the cited climatic indices have been proposed, and namely, models based on trees, black box models such as neural networks, support vector machines and nearest neighbors, and finally ensemble-based techniques as random forests have been used in order to forecast the occurrence of extreme monsoons. It can be concluded that the methodology proposed here reports promising results according to the quality parameters evaluated and predicts extreme monsoons for a temporal horizon of a month with a high accuracy. From a climatological point of view

  13. Conductivity-Based Detection Techniques in Nanofluidic Devices

    PubMed Central

    Harms, Zachary D.; Haywood, Daniel G.; Kneller, Andrew R.

    2016-01-01

    This review covers conductivity detection in fabricated nanochannels and nanopores. Improvements in nanoscale sensing are a direct result of advances in fabrication techniques, which produce devices with channels and pores with reproducible dimensions and in a variety of materials. Analytes of interest are detected by measuring changes in conductance as the analyte accumulates in the channel or passes transiently through the pore. These detection methods take advantage of phenomena enhanced at the nanoscale, such as ion current rectification, surface conductance, and dimensions comparable to the analytes of interest. The end result is the development of sensing technologies for a broad range of analytes, e.g., ions, small molecules, proteins, nucleic acids, and particles. PMID:25988434

  14. Zinc phthalocyanine thin film and chemical analyte interaction studies by density functional theory and vibrational techniques.

    PubMed

    Saini, G S S; Singh, Sukhwinder; Kaur, Sarvpreet; Kumar, Ranjan; Sathe, Vasant; Tripathi, S K

    2009-06-03

    Thin films of zinc phthalocyanine have been deposited on KBr and glass substrates by the thermal evaporation method and characterized by the x-ray diffraction, optical, infrared and Raman techniques. The observed x-ray diffraction and infrared absorption spectra of as-deposited thin films suggest the presence of an α crystalline phase. Infrared and Raman spectra of thin films after exposure to vapours of ammonia and methanol have also been recorded. Shifts in the position of some IR and Raman bands in the spectra of exposed films have been observed. Some bands also show changes in their intensity on exposure. Increased charge on the phthalocyanine ring and out-of-plane distortion of the core due to interaction between zinc phthalocyanine and vapour molecules involving the fifth coordination site of the central metal ion may be responsible for the band shifts. Changes in the intensity of bands are interpreted in terms of the lowering of molecular symmetry from D(4h) to C(4v) due to doming of the core. Molecular parameters and Mulliken atomic charges of zinc phthalocyanine and its complexes with methanol and ammonia have been calculated from density functional theory. The binding energy of the complexes have also been calculated. Calculated values of the energy for different complexes suggest that axially coordinated vapour molecules form the most stable complex. Calculated Mulliken atomic charges show net charge transfer from vapour molecules to the phthalocyanine ring for the most stable complex.

  15. INSTRUMENTS MEASURING PERCEIVED RACISM/RACIAL DISCRIMINATION: REVIEW AND CRITIQUE OF FACTOR ANALYTIC TECHNIQUES

    PubMed Central

    Atkins, Rahshida

    2015-01-01

    Several compendiums of instruments that measure perceived racism and/or discrimination are present in the literature. Other works have reviewed the psychometric properties of these instruments in terms of validity and reliability and have indicated if the instrument was factor analyzed. However, little attention has been given to the quality of the factor analysis performed. The aim of this study was to evaluate the exploratory factor analyses done on instruments measuring perceived racism/racial discrimination using guidelines from experts in psychometric theory. The techniques used for factor analysis were reviewed and critiqued and the adequacy of reporting was evaluated. Internet search engines and four electronic abstract databases were used to identify 16 relevant instruments that met the inclusion/exclusion criteria. Principal component analysis was the most frequent method of extraction (81%). Sample sizes were adequate for factor analysis in 81 percent of studies. The majority of studies reported appropriate criteria for the acceptance of un-rotated factors (81%) and justified the rotation method (75%). Exactly 94 percent of studies reported partially acceptable criteria for the acceptance of rotated factors. The majority of articles (69%) reported adequate coefficient alphas for the resultant subscales. In 81 percent of the studies, the conceptualized dimensions were supported by factor analysis. PMID:25626225

  16. Instruments measuring perceived racism/racial discrimination: review and critique of factor analytic techniques.

    PubMed

    Atkins, Rahshida

    2014-01-01

    Several compendiums of instruments that measure perceived racism and/or discrimination are present in the literature. Other works have reviewed the psychometric properties of these instruments in terms of validity and reliability and have indicated if the instrument was factor analyzed. However, little attention has been given to the quality of the factor analysis performed. The aim of this study was to evaluate the exploratory factor analyses done on instruments measuring perceived racism/racial discrimination using guidelines from experts in psychometric theory. The techniques used for factor analysis were reviewed and critiqued and the adequacy of reporting was evaluated. Internet search engines and four electronic abstract databases were used to identify 16 relevant instruments that met the inclusion/exclusion criteria. Principal component analysis was the most frequent method of extraction (81%). Sample sizes were adequate for factor analysis in 81 percent of studies. The majority of studies reported appropriate criteria for the acceptance of un-rotated factors (81%) and justified the rotation method (75%). Exactly 94 percent of studies reported partially acceptable criteria for the acceptance of rotated factors. The majority of articles (69%) reported adequate coefficient alphas for the resultant subscales. In 81 percent of the studies, the conceptualized dimensions were supported by factor analysis.

  17. Air pollution study in Croatia using moss biomonitoring and ICP-AES and AAS analytical techniques.

    PubMed

    Špirić, Zdravko; Vučković, Ivana; Stafilov, Trajče; Kušan, Vladimir; Frontasyeva, Marina

    2013-07-01

    Moss biomonitoring technique was applied in a heavy-metal pollution study of Croatia in 2006 when this country participated in the European moss survey for the first time. This survey was repeated in 2010, and the results are presented in this study. For this purpose, 121 moss samples were collected during summer and autumn 2010. The content of 21 elements was determined by inductively coupled plasma-atomic emission spectrometry and atomic absorption spectrometry. Principal component analyses was applied to show the association between the elements. Six factors (F1-F6) were determined, of which two are anthropogenic (F3 and F6), two are mixed geogenic-anthropogenic (F1 and F5), and two are geogenic factors (F2 and F4). Geographical distribution maps of the elements over the sampled territory were constructed using geographic information systems technology. Comparison of the median values of some of the anthropogenic elements-such as arsenic, cadmium, chromium, copper, mercury, nickel, lead, vanadium, and zinc-with those from the 2006 study shows that anthropogenic pollution has changed insignificantly during the last 5 years. The data obtained in the investigation in Norway are taken for comparison with pristine area, which indicates that Croatia is somewhat polluted but still, shows a more favourable picture when compared with two neighbouring countries.

  18. An environmental pressure index proposal for urban development planning based on the analytic network process

    SciTech Connect

    Gomez-Navarro, Tomas; Diaz-Martin, Diego

    2009-09-15

    This paper introduces a new approach to prioritize urban planning projects according to their environmental pressure in an efficient and reliable way. It is based on the combination of three procedures: (i) the use of environmental pressure indicators, (ii) the aggregation of the indicators in an Environmental Pressure Index by means of the Analytic Network Process method (ANP) and (iii) the interpretation of the information obtained from the experts during the decision-making process. The method has been applied to a proposal for urban development of La Carlota airport in Caracas (Venezuela). There are three options which are currently under evaluation. They include a Health Club, a Residential Area and a Theme Park. After a selection process the experts chose the following environmental pressure indicators as ANP criteria for the project life cycle: used land area, population density, energy consumption, water consumption and waste generation. By using goal-oriented questionnaires designed by the authors, the experts determined the importance of the criteria, the relationships among criteria, and the relationships between the criteria and the urban development alternatives. The resulting data showed that water consumption is the most important environmental pressure factor, and the Theme Park project is by far the urban development alternative which exerts the least environmental pressure on the area. The participating experts coincided in appreciating the technique proposed in this paper is useful and, for ranking ordering these alternatives, an improvement from traditional techniques such as environmental impact studies, life-cycle analysis, etc.

  19. Quantification of residual crystallinity in ball milled commercially sourced lactose monohydrate by thermo-analytical techniques and terahertz spectroscopy.

    PubMed

    Smith, Geoff; Hussain, Amjad; Bukhari, Nadeem Irfan; Ermolina, Irina

    2015-05-01

    The quantification of crystallinity is necessary in order to be able to control the milling process. The use of thermal analysis for this assessment presents certain challenges, particularly in the case of crystal hydrates. In this study, the residual crystallinity on ball milling of lactose monohydrate (LMH), for periods up to 90min, was evaluated by thermo-analytical techniques (TGA, DSC) and terahertz spectroscopy (THz). In general, the results from one of the DSC analysis and the THz measurements agree showing a monotonous decrease in relative residual crystallinity with milling time (∼80% reduction after 60min milling) and a slight increase at the 90min time point. However, the estimates from TGA and two other methods of analyzing DSC curve do not agree with the former techniques and show variability with significantly higher estimates for crystallinity. It was concluded that, the thermal techniques require more complex treatment of the data in the evaluation of changes in crystallinity of a milled material (in particular to account for the de-vitrification and mutarotation of the material that inevitably occurs during the measurement cycle) while the analysis of THz data is more straightforward, with the measurement having no impact on the native state of the material. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Reliable screening of various foodstuffs with respect to their irradiation status: A comparative study of different analytical techniques

    NASA Astrophysics Data System (ADS)

    Ahn, Jae-Jun; Akram, Kashif; Kwak, Ji-Young; Jeong, Mi-Seon; Kwon, Joong-Ho

    2013-10-01

    Cost-effective and time-efficient analytical techniques are required to screen large food lots in accordance to their irradiation status. Gamma-irradiated (0-10 kGy) cinnamon, red pepper, black pepper, and fresh paprika were investigated using photostimulated luminescence (PSL), direct epifluorescent filter technique/the aerobic plate count (DEFT/APC), and electronic-nose (e-nose) analyses. The screening results were also confirmed with thermoluminescence analysis. PSL analysis discriminated between irradiated (positive, >5000 PCs) and non-irradiated (negative, <700 PCs) cinnamon and red peppers. Black pepper had intermediate results (700-5000 PCs), while paprika had low sensitivity (negative results) upon irradiation. The DEFT/APC technique also showed clear screening results through the changes in microbial profiles, where the best results were found in paprika, followed by red pepper and cinnamon. E-nose analysis showed a dose-dependent discrimination in volatile profiles upon irradiation through principal component analysis. These methods can be used considering their potential applications for the screening analysis of irradiated foods.

  1. Incorporating Students' Self-Designed, Research-Based Analytical Chemistry Projects into the Instrumentation Curriculum

    ERIC Educational Resources Information Center

    Gao, Ruomei

    2015-01-01

    In a typical chemistry instrumentation laboratory, students learn analytical techniques through a well-developed procedure. Such an approach, however, does not engage students in a creative endeavor. To foster the intrinsic motivation of students' desire to learn, improve their confidence in self-directed learning activities and enhance their…

  2. Incorporating Students' Self-Designed, Research-Based Analytical Chemistry Projects into the Instrumentation Curriculum

    ERIC Educational Resources Information Center

    Gao, Ruomei

    2015-01-01

    In a typical chemistry instrumentation laboratory, students learn analytical techniques through a well-developed procedure. Such an approach, however, does not engage students in a creative endeavor. To foster the intrinsic motivation of students' desire to learn, improve their confidence in self-directed learning activities and enhance their…

  3. Towards a green analytical laboratory: microextraction techniques as a useful tool for the monitoring of polluted soils

    NASA Astrophysics Data System (ADS)

    Lopez-Garcia, Ignacio; Viñas, Pilar; Campillo, Natalia; Hernandez Cordoba, Manuel; Perez Sirvent, Carmen

    2016-04-01

    Microextraction techniques are a valuable tool at the analytical laboratory since they allow sensitive measurements of pollutants to be carried out by means of easily available instrumentation. There is a large number of such procedures involving miniaturized liquid-liquid or liquid-solid extractions with the common denominator of using very low amounts (only a few microliters) or even none of organic solvents. Since minimal amounts of reagents are involved, and the generation of residues is consequently minimized, the approach falls within the concept of Green Analytical Chemistry. This general methodology is useful both for inorganic and organic pollutants. Thus, low amounts of metallic ions can be measured without the need of using ICP-MS since this instrument can be replaced by a simple AAS spectrometer which is commonly present in any laboratory and involves low acquisition and maintenance costs. When dealing with organic pollutants, the microextracts obtained can be introduced into liquid or gas chromatographs equipped with common detectors and there is no need for the most sophisticated and expensive mass spectrometers. This communication reports an overview of the advantages of such a methodology, and gives examples for the determination of some particular contaminants in soil and water samples The authors are grateful to the Comunidad Autonóma de la Región de Murcia , Spain (Fundación Séneca, 19888/GERM/15) for financial support

  4. An analytic study of near terminal area optimal sequencing and flow control techniques

    NASA Technical Reports Server (NTRS)

    Park, S. K.; Straeter, T. A.; Hogge, J. E.

    1973-01-01

    Optimal flow control and sequencing of air traffic operations in the near terminal area are discussed. The near terminal area model is based on the assumptions that the aircraft enter the terminal area along precisely controlled approach paths and that the aircraft are segregated according to their near terminal area performance. Mathematical models are developed to support the optimal path generation, sequencing, and conflict resolution problems.

  5. A rapid analytical technique for the determination of energy expenditure by the doubly labelled water method.

    PubMed

    Barrie, A; Coward, W A

    1985-09-01

    The doubly labelled water method involves the administration of water enriched in 2H and 18O followed by determination of the turnover rates of these isotopes. Since 18O is eliminated from the body as both CO2 and water, while 2H leaves only as water, the difference between the two turnover rates provides a measure of CO2 production and hence energy expenditure. Isotopic analysis by conventional stable isotope ratio analysis (SIRA) is labour intensive and time consuming, as it requires off-line conversion of water samples to gases (H2 and CO2) followed by sequential analysis for each of the two isotopes using the mass spectrometer. Lack of suitable automated instrumentation with the ability to process large numbers of samples has prevented routine application of the method. We describe here an automated technique in which body water samples (urine, saliva, breath water or milk) are analysed simultaneously for 2H and 18O. The single bench system comprises two mass spectrometer analysers, one for measuring 2H from H2 gas, the other for measuring 18O from the water vapour (masses 18, 20). Both analysers share a common heated inlet system into which microlitre quantities of the body fluids are injected from an autosampler (102 samples). The water vapour flows both directly to one analyser for 18O measurement and into a uranium reduction furnace for conversion to H2, prior to 2H measurement by the second analyser. Both analysers also share vacuum and electronic components, enabling savings in both space and cost. In this paper we present results illustrating performance characteristics and procedures for routine application to human subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. On the control of propagating acoustic waves in sonic crystals: analytical, numerical and optimization techniques

    NASA Astrophysics Data System (ADS)

    Garcia, D. Vincent Romero

    The control of the acoustical properties of the sonic crystals (SC) needs the study of both the distribution of the scatterers in the structure and the intrinsic acoustical properties of the scatterers. In this work an exhaustive analysis of the distribution of the scatterers as well as the improvement of the acoustical properties of the SC made of scatterers with absorbent and/or resonant properties is presented. Both procedures, working together or independently, provide real possibilities to control the propagation of acoustic waves through SC. From the theoretical point of view, the wave propagation through periodic and quasiperiodic structures has been analysed by means of the multiple scattering theory, the plane wave expansion and the finite elements method. A novel extension of the plane wave expansion allowing the complex relation dispersion for SC is presented in this work. This technique complements the provided information using the classical methods and it allows us to analyse the evanescent behaviour of the modes inside of the band gaps as well as the evanescent behaviour of localized modes around the point defects in SC. The necessity of accurate measurements of the acoustical properties of the SC has motivated the development of a novel three-dimensional acquisition system that synchronises the motion of the receiver and acquisition of the temporal signals. A good agreement between the theoretical and experimental data is shown in this work. The joint work between the optimized structures of scatterers and the intrinsic properties of the scatterers themselves is applied to generate devices that present wide ranges of attenuated frequencies. These systems are presented as an alternative to the classic acoustic barrier where the propagation of waves through SC can be controlled. The results help to correctly understand the behaviour of SC for the localization of sound and for the design of both wave guides and acoustic filters.

  7. Electrospray Ionization Mass Spectrometry: A Technique to Access the Information beyond the Molecular Weight of the Analyte

    PubMed Central

    Banerjee, Shibdas; Mazumdar, Shyamalava

    2012-01-01

    The Electrospray Ionization (ESI) is a soft ionization technique extensively used for production of gas phase ions (without fragmentation) of thermally labile large supramolecules. In the present review we have described the development of Electrospray Ionization mass spectrometry (ESI-MS) during the last 25 years in the study of various properties of different types of biological molecules. There have been extensive studies on the mechanism of formation of charged gaseous species by the ESI. Several groups have investigated the origin and implications of the multiple charge states of proteins observed in the ESI-mass spectra of the proteins. The charged analytes produced by ESI can be fragmented by activating them in the gas-phase, and thus tandem mass spectrometry has been developed, which provides very important insights on the structural properties of the molecule. The review will highlight recent developments and emerging directions in this fascinating area of research. PMID:22611397

  8. 2,4-Toluene diamines--their carcinogenicity, biodegradation, analytical techniques and an approach towards development of biosensors.

    PubMed

    Shanmugam, K; Subrahmanyam, S; Tarakad, S V; Kodandapani, N; Stanly, D F

    2001-12-01

    2,4-Toluene diamine (TDA), a class A carcinogen, is a major raw material for the production of toluene diisocyanate (TDI), which is one of the precursors for the production of polyurethane foams (PU). This review deals with 2,4-toluene diamine's (TDA) carcinogenicity, analytical techniques, biodegradation and use as a biosensor for biogenic and synthetic amines, emphasizing various carcinogenicity studies by 2,4-TDA on animals and humans. This review reports some publications of the analysis of body fluid samples of workers from a PU producing factory for presence of TDA and TDI, since TDI gets absorbed into the worker's body, getting metabolized into TDA. Biodegradations of 2,4-TDA by various researchers are reported and also our own research experience with biodegradation of 2,4-TDA using Aspergillus nidulans isolated from soil site at a polyurethane foam dumping site have been discussed in this review. Biosensors for various biogenic and synthetic amines are discussed.

  9. Determination and identification of synthetic cannabinoids and their metabolites in different matrices by modern analytical techniques - a review.

    PubMed

    Znaleziona, Joanna; Ginterová, Pavlína; Petr, Jan; Ondra, Peter; Válka, Ivo; Ševčík, Juraj; Chrastina, Jan; Maier, Vítězslav

    2015-05-18

    Synthetic cannabinoids have gained popularity due to their easy accessibility and psychoactive effects. Furthermore, they cannot be detected in urine by routine drug monitoring. The wide range of active ingredients in analyzed matrices hinders the development of a standard analytical method for their determination. Moreover, their possible side effects are not well known which increases the danger. This review is focused on the sample preparation and the determination of synthetic cannabinoids in different matrices (serum, urine, herbal blends, oral fluid, hair) published since 2004. The review includes separation and identification techniques, such as thin layer chromatography, gas and liquid chromatography and capillary electrophoresis, mostly coupled with mass spectrometry. The review also includes results by spectral methods like infrared spectroscopy, nuclear magnetic resonance or direct-injection mass spectrometry.

  10. Painted Fiberglass-Reinforced Contemporary Sculpture: Investigating Composite Materials, Techniques and Conservation Using a Multi-Analytical Approach.

    PubMed

    Salvadori, Barbara; Cantisani, Emma; Colombini, Maria Perla; Tognon, Cecilia Gaia Rachele

    2016-01-01

    A multi-analytical approach was used to study the constituent materials, manufacturing technique, and state of conservation of a contemporary sculpture. This sculpture, entitled Nuredduna, was created by Aligi Sassu in 1995 and is located in the "Bellariva garden" in Florence (Italy). Fourier transform infrared spectroscopy (FT-IR), optical and electronic microscopy (OM and SEM-EDS), X-ray diffraction (XRD), and portable X-ray fluorescence (XRF) highlighted the multi-layered structure of the statue: fiberglass and an overlay of different layers (gel coat) applied with an unsaturated polyester resin added with aggregate materials and bromine compounds. A top-coat in acrylic black varnish, used as a finish, was also found. The combination of these materials with their different compositions, environmental impact, and even vandalism have negatively affected the state of conservation of Nuredduna, causing the loss of strata in its lower parts (legs and feet).

  11. Advanced analytical techniques for the extraction and characterization of plant-derived essential oils by gas chromatography with mass spectrometry.

    PubMed

    Waseem, Rabia; Low, Kah Hin

    2015-02-01

    In recent years, essential oils have received a growing interest because of the positive health effects of their novel characteristics such as antibacterial, antifungal, and antioxidant activities. For the extraction of plant-derived essential oils, there is the need of advanced analytical techniques and innovative methodologies. An exhaustive study of hydrodistillation, supercritical fluid extraction, ultrasound- and microwave-assisted extraction, solid-phase microextraction, pressurized liquid extraction, pressurized hot water extraction, liquid-liquid extraction, liquid-phase microextraction, matrix solid-phase dispersion, and gas chromatography (one- and two-dimensional) hyphenated with mass spectrometry for the extraction through various plant species and analysis of essential oils has been provided in this review. Essential oils are composed of mainly terpenes and terpenoids with low-molecular-weight aromatic and aliphatic constituents that are particularly important for public health. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Investigation of Stainless Steel Corrosion in Ultrahigh-Purity Water and Steam Systems by Surface Analytical Techniques

    NASA Astrophysics Data System (ADS)

    Dong, Xia; Iacocca, Ronald G.; Bustard, Bethany L.; Kemp, Craig A. J.

    2010-02-01

    Stainless steel pipes with different degrees of rouging and a Teflon®-coated rupture disc with severe corrosion were thoroughly investigated by combining multiple surface analytical techniques. The surface roughness and iron oxide layer thickness increase with increasing rouge severity, and the chromium oxide layer coexists with the iron oxide layer in samples with various degrees of rouging. Unlike the rouging observed for stainless steel pipes, the fast degradation of the rupture disc was caused by a crevice corrosion environment created by perforations in the protective Teflon coating. This failure analysis clearly shows the highly corrosive nature of ultrapure water used in the manufacture of pharmaceutical products, and demonstrates some of the unexpected corrosion mechanisms that can be encountered in these environments.

  13. Observer-based controller for nonlinear analytical systems

    NASA Astrophysics Data System (ADS)

    Elloumi, S.; Belhouane, M. M.; Benhadj Braiek, N.

    2016-06-01

    In this paper, we propose to design a polynomial observer-based control for nonlinear systems and to determine sufficient linear matrix inequality (LMI) global stabilisation conditions of the polynomial controlled system augmented by its observer. The design of the observer-based control leverages some notations from the Kronecker product and the power of matrices properties for the state space description of polynomial systems. The stability study of the polynomial controlled system augmented by its observer is based on the Lyapunov stability direct method. Intensive simulations are performed to illustrate the validity and the effectiveness of the polynomial approach used to design the control.

  14. Fully automated analytical procedure for propofol determination by sequential injection technique with spectrophotometric and fluorimetric detections.

    PubMed

    Šrámková, Ivana; Amorim, Célia G; Sklenářová, Hana; Montenegro, Maria C B M; Horstkotte, Burkhard; Araújo, Alberto N; Solich, Petr

    2014-01-01

    In this work, an application of an enzymatic reaction for the determination of the highly hydrophobic drug propofol in emulsion dosage form is presented. Emulsions represent a complex and therefore challenging matrix for analysis. Ethanol was used for breakage of a lipid emulsion, which enabled optical detection. A fully automated method based on Sequential Injection Analysis was developed, allowing propofol determination without the requirement of tedious sample pre-treatment. The method was based on spectrophotometric detection after the enzymatic oxidation catalysed by horseradish peroxidase and subsequent coupling with 4-aminoantipyrine leading to a coloured product with an absorbance maximum at 485 nm. This procedure was compared with a simple fluorimetric method, which was based on the direct selective fluorescence emission of propofol in ethanol at 347 nm. Both methods provide comparable validation parameters with linear working ranges of 0.005-0.100 mg mL(-1) and 0.004-0.243 mg mL(-1) for the spectrophotometric and fluorimetric methods, respectively. The detection and quantitation limits achieved with the spectrophotometric method were 0.0016 and 0.0053 mg mL(-1), respectively. The fluorimetric method provided the detection limit of 0.0013 mg mL(-1) and limit of quantitation of 0.0043 mg mL(-1). The RSD did not exceed 5% and 2% (n=10), correspondingly. A sample throughput of approx. 14 h(-1) for the spectrophotometric and 68 h(-1) for the fluorimetric detection was achieved. Both methods proved to be suitable for the determination of propofol in pharmaceutical formulation with average recovery values of 98.1 and 98.5%.

  15. Investigating dissolved organic matter decomposition in northern peatlands using complimentary analytical techniques

    NASA Astrophysics Data System (ADS)

    Tfaily, Malak M.; Hamdan, Rasha; Corbett, Jane E.; Chanton, Jeffrey P.; Glaser, Paul H.; Cooper, William T.

    2013-07-01

    The chemical transformations that govern storage, degradation, and loss of organic matter in northern peatlands are poorly characterized, despite the significance of these peat deposits as pivotal reservoirs in the global carbon cycle. One of the most challenging problems concerns the character of dissolved organic matter (DOM) in peat porewaters, particularly higher-molecular weight compounds that may function either as non-reactive sinks or reactive intermediates for organic byproducts of microbial decay. The complexity of these large molecules has defied attempts to characterize their molecular structure in bulk samples with a high degree of precision. We therefore determined the composition and reactivity of DOM from representative bog and fen sites in the Glacial Lake Agassiz Peatlands (GLAP) in northern Minnesota, USA. We applied four complementary techniques: electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS), proton nuclear magnetic resonance spectroscopy (1H NMR), specific UV absorbance (SUVA) and excitation-emission matrix (EEM) fluorescence spectroscopy. We observed that the vast majority (>80%) of molecular formulas that appear in the surface bog DOM are also present at 2.9 m depth, indicating that much of DOM in the bog is resistant to microbial degradation. In contrast to bog samples, a considerable number of new compounds with low O/C and high H/C elemental ratios were observed in the 3 m fen horizon relative to surface samples. These results indicate a more pronounced difference in the composition of surface and deep DOM in the fen. SUVA, determined at 254 nm, indicated significantly lower aromaticity in deep fen samples relative to deep bog samples. This trend was verified by 1H NMR. Aromatic and carbohydrate components represented up to 70% of deep bog DOM but comprised a much smaller proportion of deep fen DOM, which was dominated by functionalized and non-functionalized aliphatics. Molecular

  16. Analytical Tools for Investigating and Modeling Agent-Based Systems

    DTIC Science & Technology

    2005-06-01

    to be high. For example, the binomial distribution can be used to derive the expected number of objects x1 in sample A with a matching object x2 in B...6] and development of models that select attribute estimators based on data characteristics. 7. Acknowledgments We thank Ross Fairgrieve for his...best pre- diction of tomorrow’s stock prices is based on today’s prices (Wooldrige, 2003). 1 If a conventional linear regression model is used to

  17. The pH-dependant attachment of ceria nanoparticles to silica using surface analytical techniques

    NASA Astrophysics Data System (ADS)

    Dawkins, K.; Rudyk, B. W.; Xu, Z.; Cadien, K.

    2015-08-01

    The adhesion and removal of ceria particles to a silica surface was investigated with the use of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and auger electron spectroscopy (AES) measurements. A model is presented based on electrophoretic mobility measurements of ceria slurry and silica particles at different pH's. XPS results show that at acidic pH values, ceria is present on silica surfaces, but at alkaline pH values, far less ceria is present, or no ceria is present in the extreme case. SEM results corroborated the XPS results showing uniform distribution of ceria particles on silica surface at pH 6 while a clean silica surface is observed at pH 12. However, SEM images show agglomeration of ceria particles occurring at the isoelectric point of ceria at ∼pH 9.6. High resolution Ce 3d XPS analysis indicates that ceria present on the surface is composed ∼31% Ce(III) and ∼69% Ce(IV). AES mapping done at specific points on the silica surface validated both XPS and SEM results. Based on XPS, SEM and AES analyses, it is clear that an alkaline pH is necessary to minimize particulate contamination of silica surface by ceria.

  18. Applications of Fractal Analytical Techniques in the Estimation of Operational Scale

    NASA Technical Reports Server (NTRS)

    Emerson, Charles W.; Quattrochi, Dale A.

    2000-01-01

    The observational scale and the resolution of remotely sensed imagery are essential considerations in the interpretation process. Many atmospheric, hydrologic, and other natural and human-influenced spatial phenomena are inherently scale dependent and are governed by different physical processes at different spatial domains. This spatial and operational heterogeneity constrains the ability to compare interpretations of phenomena and processes observed in higher spatial resolution imagery to similar interpretations obtained from lower resolution imagery. This is a particularly acute problem, since longterm global change investigations will require high spatial resolution Earth Observing System (EOS), Landsat 7, or commercial satellite data to be combined with lower resolution imagery from older sensors such as Landsat TM and MSS. Fractal analysis is a useful technique for identifying the effects of scale changes on remotely sensed imagery. The fractal dimension of an image is a non-integer value between two and three which indicates the degree of complexity in the texture and shapes depicted in the image. A true fractal surface exhibits self-similarity, a property of curves or surfaces where each part is indistinguishable from the whole, or where the form of the curve or surface is invariant with respect to scale. Theoretically, if the digital numbers of a remotely sensed image resemble an ideal fractal surface, then due to the self-similarity property, the fractal dimension of the image will not vary with scale and resolution, and the slope of the fractal dimension-resolution relationship would be zero. Most geographical phenomena, however, are not self-similar at all scales, but they can be modeled by a stochastic fractal in which the scaling properties of the image exhibit patterns that can be described by statistics such as area-perimeter ratios and autocovariances. Stochastic fractal sets relax the self-similarity assumption and measure many scales and

  19. Analytical modeling of structure-soil systems for lunar bases

    NASA Technical Reports Server (NTRS)

    Macari-Pasqualino, Jose Emir

    1989-01-01

    The study of the behavior of granular materials in a reduced gravity environment and under low effective stresses became a subject of great interest in the mid 1960's when NASA's Surveyor missions to the Moon began the first extraterrestrial investigation and it was found that Lunar soils exhibited properties quite unlike those on Earth. This subject gained interest during the years of the Apollo missions and more recently due to NASA's plans for future exploration and colonization of Moon and Mars. It has since been clear that a good understanding of the mechanical properties of granular materials under reduced gravity and at low effective stress levels is of paramount importance for the design and construction of surface and buried structures on these bodies. In order to achieve such an understanding it is desirable to develop a set of constitutive equations that describes the response of such materials as they are subjected to tractions and displacements. This presentation examines issues associated with conducting experiments on highly nonlinear granular materials under high and low effective stresses. The friction and dilatancy properties which affect the behavior of granular soils with low cohesion values are assessed. In order to simulate the highly nonlinear strength and stress-strain behavior of soils at low as well as high effective stresses, a versatile isotropic, pressure sensitive, third stress invariant dependent, cone-cap elasto-plastic constitutive model was proposed. The integration of the constitutive relations is performed via a fully implicit Backward Euler technique known as the Closest Point Projection Method. The model was implemented into a finite element code in order to study nonlinear boundary value problems associated with homogeneous as well as nonhomogeneous deformations at low as well as high effective stresses. The effect of gravity (self-weight) on the stress-strain-strength response of these materials is evaluated. The calibration

  20. Analytical modeling of structure-soil systems for lunar bases

    NASA Technical Reports Server (NTRS)

    Macari-Pasqualino, Jose Emir

    1989-01-01

    The study of the behavior of granular materials in a reduced gravity environment and under low effective stresses became a subject of great interest in the mid 1960's when NASA's Surveyor missions to the Moon began the first extraterrestrial investigation and it was found that Lunar soils exhibited properties quite unlike those on Earth. This subject gained interest during the years of the Apollo missions and more recently due to NASA's plans for future exploration and colonization of Moon and Mars. It has since been clear that a good understanding of the mechanical properties of granular materials under reduced gravity and at low effective stress levels is of paramount importance for the design and construction of surface and buried structures on these bodies. In order to achieve such an understanding it is desirable to develop a set of constitutive equations that describes the response of such materials as they are subjected to tractions and displacements. This presentation examines issues associated with conducting experiments on highly nonlinear granular materials under high and low effective stresses. The friction and dilatancy properties which affect the behavior of granular soils with low cohesion values are assessed. In order to simulate the highly nonlinear strength and stress-strain behavior of soils at low as well as high effective stresses, a versatile isotropic, pressure sensitive, third stress invariant dependent, cone-cap elasto-plastic constitutive model was proposed. The integration of the constitutive relations is performed via a fully implicit Backward Euler technique known as the Closest Point Projection Method. The model was implemented into a finite element code in order to study nonlinear boundary value problems associated with homogeneous as well as nonhomogeneous deformations at low as well as high effective stresses. The effect of gravity (self-weight) on the stress-strain-strength response of these materials is evaluated. The calibration

  1. A measurement-based analytical approach to the bioluminescence tomography problem

    NASA Astrophysics Data System (ADS)

    Erkol, Hakan; Demirkiran, Aytac; Kipergil, Esra-Aytac; Uluc, Nasire; Unlu, Mehmet B.

    2014-03-01

    This work presents an analytical approach for the solution of the tissue diffusion equation based on the bound- ary measurements. We consider a bioluminescent point source in both homogeneous and heterogeneous circular turbid media. The point source is described by the Dirac delta function. Analytical expressions for the strength and position of the point source are obtained introducing boundary measurements and then applying appropriate boundary conditions. In addition, numerical simulations are performed for the position of the source. Calculations show that that the analytical results are in a good accordance with the numerical results.

  2. Recent applications of carbon-based nanomaterials in analytical chemistry: critical review.

    PubMed

    Scida, Karen; Stege, Patricia W; Haby, Gabrielle; Messina, Germán A; García, Carlos D

    2011-04-08

    The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of nanomaterials on the development of novel analytical applications, developments reported in the 2005-2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry.

  3. Recent Applications of Carbon-Based Nanomaterials in Analytical Chemistry: Critical Review

    PubMed Central

    Scida, Karen; Stege, Patricia W.; Haby, Gabrielle; Messina, Germán A.; García, Carlos D.

    2011-01-01

    The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of nanomaterials on the development of novel analytical applications, developments reported in the 2005–2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry. PMID:21458626

  4. Moving beyond regression techniques in cardiovascular risk prediction: applying machine learning to address analytic challenges.

    PubMed

    Goldstein, Benjamin A; Navar, Ann Marie; Carter, Rickey E

    2016-07-19

    Risk prediction plays an important role in clinical cardiology research. Traditionally, most risk models have been based on regression models. While useful and robust, these statistical methods are limited to using a small number of predictors which operate in the same way on everyone, and uniformly throughout their range. The purpose of this review is to illustrate the use of machine-learning methods for development of risk prediction models. Typically presented as black box approaches, most machine-learning methods are aimed at solving particular challenges that arise in data analysis that are not well addressed by typical regression approaches. To illustrate these challenges, as well as how different methods can address them, we consider trying to predicting mortality after diagnosis of acute myocardial infarction. We use data derived from our institution's electronic health record and abstract data on 13 regularly measured laboratory markers. We walk through different challenges that arise in modelling these data and then introduce different machine-learning approaches. Finally, we discuss general issues in the application of machine-learning methods including tuning parameters, loss functions, variable importance, and missing data. Overall, this review serves as an introduction for those working on risk modelling to approach the diffuse field of machine learning.

  5. Dynamics-based Nondestructive Structural Monitoring Techniques

    DTIC Science & Technology

    2012-06-21

    analytical model. Cesnik and his colleagues have developed wedge-shaped guided wave SHM transducers with interdigital sector elements, called CLoVER...finished electrodes are shown in Figure 4.2. Two 42 mm diameter disks and two 30 mm diameter disks were used in the fabrication. The electrode ...on one small disk. The other small disk has 4 segments with each segment having 4 fan- shaped electrodes . All individual electrode elements of the 4

  6. Analytic Solutions for the Spectral Responses of RCA-Grating-Based Waveguide Devices

    NASA Astrophysics Data System (ADS)

    Zeng, Xiang-Kai; Wei, Lai

    2012-12-01

    Analytic solutions (ASs) for the spectral responses of waveguide devices with raised-cosine-apodized (RCA) gratings are presented. The waveguide devices include short- and long-period RCA-gratings, RCA-grating-based interferometers as Fabry—Perot, Mach—Zehnder and Michelson interferometers. The calculations based on the analytic solutions are demonstrated and compared with those based on the transfer matrix (TM) method preferred, which has confirmed that the AS-based analysis is with enough accuracy and several thousands times the efficiency of the TM method.

  7. Downstream processing and chromatography based analytical methods for production of vaccines, gene therapy vectors, and bacteriophages

    PubMed Central

    Kramberger, Petra; Urbas, Lidija; Štrancar, Aleš

    2015-01-01

    Downstream processing of nanoplexes (viruses, virus-like particles, bacteriophages) is characterized by complexity of the starting material, number of purification methods to choose from, regulations that are setting the frame for the final product and analytical methods for upstream and downstream monitoring. This review gives an overview on the nanoplex downstream challenges and chromatography based analytical methods for efficient monitoring of the nanoplex production. PMID:25751122

  8. Downstream processing and chromatography based analytical methods for production of vaccines, gene therapy vectors, and bacteriophages.

    PubMed

    Kramberger, Petra; Urbas, Lidija; Štrancar, Aleš

    2015-01-01

    Downstream processing of nanoplexes (viruses, virus-like particles, bacteriophages) is characterized by complexity of the starting material, number of purification methods to choose from, regulations that are setting the frame for the final product and analytical methods for upstream and downstream monitoring. This review gives an overview on the nanoplex downstream challenges and chromatography based analytical methods for efficient monitoring of the nanoplex production.

  9. A novel non-imaging optics based Raman spectroscopy device for transdermal blood analyte measurement

    PubMed Central

    Kong, Chae-Ryon; Barman, Ishan; Dingari, Narahara Chari; Kang, Jeon Woong; Galindo, Luis; Dasari, Ramachandra R.; Feld, Michael S.

    2011-01-01

    Due to its high chemical specificity, Raman spectroscopy has been considered to be a promising technique for non-invasive disease diagnosis. However, during Raman excitation, less than one out of a million photons undergo spontaneous Raman scattering and such weakness in Raman scattered light often require highly efficient collection of Raman scattered light for the analysis of biological tissues. We present a novel non-imaging optics based portable Raman spectroscopy instrument designed for enhanced light collection. While the instrument was demonstrated on transdermal blood glucose measurement, it can also be used for detection of other clinically relevant blood analytes such as creatinine, urea and cholesterol, as well as other tissue diagnosis applications. For enhanced light collection, a non-imaging optical element called compound hyperbolic concentrator (CHC) converts the wide angular range of scattered photons (numerical aperture (NA) of 1.0) from the tissue into a limited range of angles accommodated by the acceptance angles of the collection system (e.g., an optical fiber with NA of 0.22). A CHC enables collimation of scattered light directions to within extremely narrow range of angles while also maintaining practical physical dimensions. Such a design allows for the development of a very efficient and compact spectroscopy system for analyzing highly scattering biological tissues. Using the CHC-based portable Raman instrument in a clinical research setting, we demonstrate successful transdermal blood glucose predictions in human subjects undergoing oral glucose tolerance tests. PMID:22125761

  10. A novel non-imaging optics based Raman spectroscopy device for transdermal blood analyte measurement

    NASA Astrophysics Data System (ADS)

    Kong, Chae-Ryon; Barman, Ishan; Dingari, Narahara Chari; Kang, Jeon Woong; Galindo, Luis; Dasari, Ramachandra R.; Feld, Michael S.

    2011-09-01

    Due to its high chemical specificity, Raman spectroscopy has been considered to be a promising technique for non-invasive disease diagnosis. However, during Raman excitation, less than one out of a million photons undergo spontaneous Raman scattering and such weakness in Raman scattered light often require highly efficient collection of Raman scattered light for the analysis of biological tissues. We present a novel non-imaging optics based portable Raman spectroscopy instrument designed for enhanced light collection. While the instrument was demonstrated on transdermal blood glucose measurement, it can also be used for detection of other clinically relevant blood analytes such as creatinine, urea and cholesterol, as well as other tissue diagnosis applications. For enhanced light collection, a non-imaging optical element called compound hyperbolic concentrator (CHC) converts the wide angular range of scattered photons (numerical aperture (NA) of 1.0) from the tissue into a limited range of angles accommodated by the acceptance angles of the collection system (e.g., an optical fiber with NA of 0.22). A CHC enables collimation of scattered light directions to within extremely narrow range of angles while also maintaining practical physical dimensions. Such a design allows for the development of a very efficient and compact spectroscopy system for analyzing highly scattering biological tissues. Using the CHC-based portable Raman instrument in a clinical research setting, we demonstrate successful transdermal blood glucose predictions in human subjects undergoing oral glucose tolerance tests.

  11. Analytic parallel-polarized light imaging technique using various light-emitting diodes: a comparison with skin conductance values.

    PubMed

    Kim, D H; Choi, J E; Ryu, H J; Seo, S H; Kye, Y C; Ahn, H H

    2015-05-01

    The quantitative difference of the light reflected from a skin surface can be analyzed using parallel-polarized light (PPL) photography when combined with an analytic technique similar to colorimetric photography. To improve the PPL photography technique as an assessment tool for the evaluation of skin condition using light-emitting diodes (LED) of different colors. Parallel-polarized light images were taken using white and green LED illuminators. The acquired images were transformed to CIELAB coordinates. An in-house skin conductance meter was constructed to assess skin hydration level. A dermatologist evaluated the clinical grading of dryness and glossiness. These clinical severities were also compared statistically with the CIELAB values. As with the green illuminator, the correlation analysis of whole sites showed that the L* value positively correlated with age (r = 0.18677, P < 0.05), and that the a* value has negative and positive relationships with age (r = -0.20528, P < 0.05) and glossiness (r = 0.20885, P < 0.05) respectively. The correlations between CIELAB values and multiple characteristics of skin were more significant when green LED was applied than when white light was applied. In addition, coherent relationships between the grade of dryness and skin conductance values showed that visual assessment could be appropriate for the study as with objective measurement. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Nuclear based techniques for detection of contraband

    SciTech Connect

    Gozani, T.

    1993-12-31

    The detection of contraband such as explosives and drugs concealed in luggage or other container can be quite difficult. Nuclear techniques offer capabilities which are essential to having effective detection devices. This report describes the features of various nuclear techniques and instrumentation.

  13. Analytical Devices Based on Direct Synthesis of DNA on Paper.

    PubMed

    Glavan, Ana C; Niu, Jia; Chen, Zhen; Güder, Firat; Cheng, Chao-Min; Liu, David; Whitesides, George M

    2016-01-05

    This paper addresses a growing need in clinical diagnostics for parallel, multiplex analysis of biomarkers from small biological samples. It describes a new procedure for assembling arrays of ssDNA and proteins on paper. This method starts with the synthesis of DNA oligonucleotides covalently linked to paper and proceeds to assemble microzones of DNA-conjugated paper into arrays capable of simultaneously capturing DNA, DNA-conjugated protein antigens, and DNA-conjugated antibodies. The synthesis of ssDNA oligonucleotides on paper is convenient and effective with 32% of the oligonucleotides cleaved and eluted from the paper substrate being full-length by HPLC for a 32-mer. These ssDNA arrays can be used to detect fluorophore-linked DNA oligonucleotides in solution, and as the basis for DNA-directed assembly of arrays of DNA-conjugated capture antibodies on paper, detect protein antigens by sandwich ELISAs. Paper-anchored ssDNA arrays with different sequences can be used to assemble paper-based devices capable of detecting DNA and antibodies in the same device and enable simple microfluidic paper-based devices.

  14. Grandmaster: Interactive text-based analytics of social media

    SciTech Connect

    Fabian, Nathan D.; Davis, Warren Leon,; Raybourn, Elaine M.; Lakkaraju, Kiran; Whetzel, Jonathan

    2015-11-01

    People use social media resources like Twitter, Facebook, forums etc. to share and discuss various activities or topics. By aggregating topic trends across many individuals using these services, we seek to construct a richer profile of a person’s activities and interests as well as provide a broader context of those activities. This profile may then be used in a variety of ways to understand groups as a collection of interests and affinities and an individual’s participation in those groups. Our approach considers that much of these data will be unstructured, free-form text. By analyzing free-form text directly, we may be able to gain an implicit grouping of individuals with shared interests based on shared conversation, and not on explicit social software linking them. In this paper, we discuss a proof-of-concept application called Grandmaster built to pull short sections of text, a person’s comments or Twitter posts, together by analysis and visualization to allow a gestalt understanding of the full collection of all individuals: how groups are similar and how they differ, based on their text inputs.

  15. Analytical Approaches Based on Gas Chromatography Mass Spectrometry (GC/MS) to Study Organic Materials in Artworks and Archaeological Objects.

    PubMed

    Bonaduce, Ilaria; Ribechini, Erika; Modugno, Francesca; Colombini, Maria Perla

    2016-02-01

    Gas chromatography/mass spectrometry (GC/MS), after appropriate wet chemical sample pre-treatments or pyrolysis, is one of the most commonly adopted analytical techniques in the study of organic materials from cultural heritage objects. Organic materials in archaeological contexts, in classical art objects, or in modern and contemporary works of art may be the same or belong to the same classes, but can also vary considerably, often presenting different ageing pathways and chemical environments. This paper provides an overview of the literature published in the last 10 years on the research based on the use of GC/MS for the analysis of organic materials in artworks and archaeological objects. The latest progresses in advancing analytical approaches, characterising materials and understanding their degradation, and developing methods for monitoring their stability are discussed. Case studies from the literature are presented to examine how the choice of the working conditions and the analytical approaches is driven by the analytical and technical question to be answered, as well as the nature of the object from which the samples are collected.

  16. A Vocal-Based Analytical Method for Goose Behaviour Recognition

    PubMed Central

    Steen, Kim Arild; Therkildsen, Ole Roland; Karstoft, Henrik; Green, Ole

    2012-01-01

    Since human-wildlife conflicts are increasing, the development of cost-effective methods for reducing damage or conflict levels is important in wildlife management. A wide range of devices to detect and deter animals causing conflict are used for this purpose, although their effectiveness is often highly variable, due to habituation to disruptive or disturbing stimuli. Automated recognition of behaviours could form a critical component of a system capable of altering the disruptive stimuli to avoid this. In this paper we present a novel method to automatically recognise goose behaviour based on vocalisations from flocks of free-living barnacle geese (Branta leucopsis). The geese were observed and recorded in a natural environment, using a shielded shotgun microphone. The classification used Support Vector Machines (SVMs), which had been trained with labeled data. Greenwood Function Cepstral Coefficients (GFCC) were used as features for the pattern recognition algorithm, as they can be adjusted to the hearing capabilities of different species. Three behaviours are classified based in this approach, and the method achieves a good recognition of foraging behaviour (86–97% sensitivity, 89–98% precision) and a reasonable recognition of flushing (79–86%, 66–80%) and landing behaviour(73–91%, 79–92%). The Support Vector Machine has proven to be a robust classifier for this kind of classification, as generality and non-linear capabilities are important. We conclude that vocalisations can be used to automatically detect behaviour of conflict wildlife species, and as such, may be used as an integrated part of a wildlife management system. PMID:22737037

  17. A dual analyte fluorescent chemosensor based on a furan-pyrene conjugate for Al3 + & HSO3-

    NASA Astrophysics Data System (ADS)

    Don, Derin; Velmurugan, K.; Prabhu, J.; Bhuvanesh, N.; Thamilselvan, A.; Nandhakumar, R.

    2017-03-01

    A simple chalcone based dual analyte fluorescent probe FPC for Al3 + and HSO3- ions was developed. FPC detects both the analytes through a "turn off-on" approach and by the PET and ICT mechanism. FPC showed high selectivity and sensitivity for Al3 + and HSO3- ions detection over other interfering and competing metal ions. In addition, the LOD of FPC for sensing Al3 + and HSO3- ions was found to be 1.60 × 10- 7 M and 0.17 × 10- 6 M respectively. An electrochemical desalination technique was employed for the complete removal of Al3 + ions from the environmental water samples by using the probe FPC.

  18. Multivariate control charts based on net analyte signal (NAS) and Raman spectroscopy for quality control of carbamazepine.

    PubMed

    Rocha, Werickson Fortunato de Carvalho; Poppi, Ronei Jesus

    2011-10-31

    Raman spectroscopy and control charts based on the net analyte signal (NAS) were applied to polymorphic characterization of carbamazepine. Carbamazepine presents four polymorphic forms: I-IV (dihydrate). X-ray powder diffraction was used as a reference technique. The control charts were built generating three charts: the NAS chart that corresponds to the analyte of interest (form III in this case), the interference chart that corresponds to the contribution of other compounds in the sample and the residual chart that corresponds to nonsystematic variations. For each chart, statistical limits were developed using samples within the quality specifications. It was possible to identify the different polymorphic forms of carbamazepine present in pharmaceutical formulations. Thus, an alternative method for the quality monitoring of the carbamazepine polymorphic forms after the crystallization process is presented.

  19. Establishment of a trimodality analytical platform for tracing, imaging and quantification of gold nanoparticles in animals by radiotracer techniques.

    PubMed

    Chen, Chien-Hung; Lin, Fong-Sian; Liao, Wei-Neng; Liang, Sanching L; Chen, Min-Hua; Chen, Yo-Wen; Lin, Wan-Yu; Hsu, Ming-Hua; Wang, Mei-Ya; Peir, Jinn-Jer; Chou, Fong-In; Chen, Ching-Ya; Chen, Sih-Yu; Huang, Su-Chin; Yang, Mo-Hsiung; Hueng, Dueng-Yuan; Hwu, Yeukuang; Yang, Chung-Shi; Chen, Jen-Kun

    2015-01-06

    This study aims to establish a (198)Au-radiotracer technique for in vivo tracing, rapid quantification, and ex vivo visualization of PEGylated gold nanoparticles (GNPs) in animals, organs and tissue dissections. The advantages of GNPs lie in its superior optical property, biocompatibility and versatile conjugation chemistry, which are promising to develop diagnostic probes and drug delivery systems. (198)Au is used as a radiotracer because it simultaneously emits beta and gamma radiations with proper energy and half-life; therefore, (198)Au can be used for bioanalytical purposes. The (198)Au-tagged radioactive gold nanoparticles ((198)Au-GNPs) were prepared simply by irradiating the GNPs in a nuclear reactor through the (197)Au(n,γ)(198)Au reaction and subsequently the (198)Au-GNPs were subjected to surface modification with polyethylene glycol to form PEGylated (198)Au-GNPs. The (198)Au-GNPs retained physicochemical properties that were the same as those of GNP before neutron irradiation. Pharmacokinetic and biodisposition studies were performed by intravenously injecting three types of (198)Au-GNPs with or without PEGylation into mice; the γ radiation in blood specimens and dissected organs was then measured. The (198)Au-radiotracer technique enables rapid quantification freed from tedious sample preparation and shows more than 95% recovery of injected GNPs. Clinical gamma scintigraphy was proved feasible to explore spatial- and temporal-resolved biodisposition of (198)Au-GNPs in living animals. Moreover, autoradiography, which recorded beta particles from (198)Au, enabled visualizing the heterogeneous biodisposition of (198)Au-GNPs in different microenvironments and tissues. In this study, the (198)Au-radiotracer technique facilitated creating a trimodality analytical platform for tracing, quantifying and imaging GNPs in animals.

  20. The Impact of Chemical Abrasion on Trace Element Analysis of Zircon by In Situ Micro-Analytical Techniques

    NASA Astrophysics Data System (ADS)

    Romanoski, A.; Coint, N.; Cottle, J. M.; Hetherington, C. J.; Barnes, C. G.

    2011-12-01

    Introduction of the chemical abrasion technique has significantly increased the precision and accuracy of ID-TIMS U-Pb dating of zircon. The chemical abrasion technique, coupled with thermal annealing, removes inclusions and metamict domains from zircon reducing the impact of Pb-loss leading to more concordant analyses.In this study, zircon from the Red Bluff Granitic Suite (TX) (ID-TIMS age 1120 ± 35 Ma) has been thermally annealed and chemically abraded prior to SHRIMP-RG and LA-MC-ICP-MS analysis.Chemically abraded zircon gives a date of 1109 ± 22 Ma with an average of 3% discordancy. This compares with dates of 1137 ± 48 Ma with an average of 39% discordancy for non-abraded zircon from the same sample. The dates overlap within uncertainty, but the age from chemically abraded zircon has a lower population uncertainty. Other petrographic and analytical observations of the chemically abraded zircon include brighter CL intensity, lower REE abundances, more consistent (smaller scatter) negative Eu/Eu* anomalies, less scatter in the chondrite-normalized LREE values, and a slightly less-steep chondrite normalized HREE slope. The data show that thermal annealing and chemical abrasion of zircon prior to analysis by in situ ion-beam or laser ablation techniques may result in better accuracy and greater concordance in U-Pb analysis of zircon. However, while improving the quality of some components of the trace element dataset (e.g. Eu anomalies) the process may prejudice the interpretation of zircon trace element data (e.g. HREECN slopes).

  1. Analytical transmissibility based transfer path analysis for multi-energy-domain systems using four-pole parameter theory

    NASA Astrophysics Data System (ADS)

    Mashayekhi, Mohammad Jalali; Behdinan, Kamran

    2017-10-01

    The increasing demand to minimize undesired vibration and noise levels in several high-tech industries has generated a renewed interest in vibration transfer path analysis. Analyzing vibration transfer paths within a system is of crucial importance in designing an effective vibration isolation strategy. Most of the existing vibration transfer path analysis techniques are empirical which are suitable for diagnosis and troubleshooting purpose. The lack of an analytical transfer path analysis to be used in the design stage is the main motivation behind this research. In this paper an analytical transfer path analysis based on the four-pole theory is proposed for multi-energy-domain systems. Bond graph modeling technique which is an effective approach to model multi-energy-domain systems is used to develop the system model. In this paper an electro-mechanical system is used as a benchmark example to elucidate the effectiveness of the proposed technique. An algorithm to obtain the equivalent four-pole representation of a dynamical systems based on the corresponding bond graph model is also presented in this paper.

  2. Biological Matrix Effects in Quantitative Tandem Mass Spectrometry-Based Analytical Methods: Advancing Biomonitoring

    PubMed Central

    Panuwet, Parinya; Hunter, Ronald E.; D’Souza, Priya E.; Chen, Xianyu; Radford, Samantha A.; Cohen, Jordan R.; Marder, M. Elizabeth; Kartavenka, Kostya; Ryan, P. Barry; Barr, Dana Boyd

    2015-01-01

    The ability to quantify levels of target analytes in biological samples accurately and precisely, in biomonitoring, involves the use of highly sensitive and selective instrumentation such as tandem mass spectrometers and a thorough understanding of highly variable matrix effects. Typically, matrix effects are caused by co-eluting matrix components that alter the ionization of target analytes as well as the chromatographic response of target analytes, leading to reduced or increased sensitivity of the analysis. Thus, before the desired accuracy and precision standards of laboratory data are achieved, these effects must be characterized and controlled. Here we present our review and observations of matrix effects encountered during the validation and implementation of tandem mass spectrometry-based analytical methods. We also provide systematic, comprehensive laboratory strategies needed to control challenges posed by matrix effects in order to ensure delivery of the most accurate data for biomonitoring studies assessing exposure to environmental toxicants. PMID:25562585

  3. DCT-based cyber defense techniques

    NASA Astrophysics Data System (ADS)

    Amsalem, Yaron; Puzanov, Anton; Bedinerman, Anton; Kutcher, Maxim; Hadar, Ofer

    2015-09-01

    With the increasing popularity of video streaming services and multimedia sharing via social networks, there is a need to protect the multimedia from malicious use. An attacker may use steganography and watermarking techniques to embed malicious content, in order to attack the end user. Most of the attack algorithms are robust to basic image processing techniques such as filtering, compression, noise addition, etc. Hence, in this article two novel, real-time, defense techniques are proposed: Smart threshold and anomaly correction. Both techniques operate at the DCT domain, and are applicable for JPEG images and H.264 I-Frames. The defense performance was evaluated against a highly robust attack, and the perceptual quality degradation was measured by the well-known PSNR and SSIM quality assessment metrics. A set of defense techniques is suggested for improving the defense efficiency. For the most aggressive attack configuration, the combination of all the defense techniques results in 80% protection against cyber-attacks with PSNR of 25.74 db.

  4. A structurally based analytic model of growth and biomass dynamics in single species stands of conifers

    Treesearch

    Robin J. Tausch

    2015-01-01

    A theoretically based analytic model of plant growth in single species conifer communities based on the species fully occupying a site and fully using the site resources is introduced. Model derivations result in a single equation simultaneously describes changes over both, different site conditions (or resources available), and over time for each variable for each...

  5. Approaching near real-time biosensing: microfluidic microsphere based biosensor for real-time analyte detection.

    PubMed

    Cohen, Noa; Sabhachandani, Pooja; Golberg, Alexander; Konry, Tania

    2015-04-15

    In this study we describe a simple lab-on-a-chip (LOC) biosensor approach utilizing well mixed microfluidic device and a microsphere-based assay capable of performing near real-time diagnostics of clinically relevant analytes such cytokines and antibodies. We were able to overcome the adsorption kinetics reaction rate-limiting mechanism, which is diffusion-controlled in standard immunoassays, by introducing the microsphere-based assay into well-mixed yet simple microfluidic device with turbulent flow profiles in the reaction regions. The integrated microsphere-based LOC device performs dynamic detection of the analyte in minimal amount of biological specimen by continuously sampling micro-liter volumes of sample per minute to detect dynamic changes in target analyte concentration. Furthermore we developed a mathematical model for the well-mixed reaction to describe the near real time detection mechanism observed in the developed LOC method. To demonstrate the specificity and sensitivity of the developed real time monitoring LOC approach, we applied the device for clinically relevant analytes: Tumor Necrosis Factor (TNF)-α cytokine and its clinically used inhibitor, anti-TNF-α antibody. Based on the reported results herein, the developed LOC device provides continuous sensitive and specific near real-time monitoring method for analytes such as cytokines and antibodies, reduces reagent volumes by nearly three orders of magnitude as well as eliminates the washing steps required by standard immunoassays.

  6. Nasal base narrowing: the combined alar base excision technique.

    PubMed

    Foda, Hossam M T

    2007-01-01

    To evaluate the role of the combined alar base excision technique in narrowing the nasal base and correcting excessive alar flare. The study included 60 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined an external alar wedge resection with an internal vestibular floor excision. All cases were followed up for a mean of 32 (range, 12-144) months. Nasal tip modification and correction of any preexisting caudal septal deformities were always completed before the nasal base narrowing. The mean width of the external alar wedge excised was 7.2 (range, 4-11) mm, whereas the mean width of the sill excision was 3.1 (range, 2-7) mm. Completing the internal excision first resulted in a more conservative external resection, thus avoiding any blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid formation were encountered, and the external alar wedge excision healed with an inconspicuous scar that was well hidden in the depth of the alar-facial crease. Finally, the risk of notching of the alar rim, which can occur at the junction of the external and internal excisions, was significantly reduced by adopting a 2-layered closure of the vestibular floor (P = .01). The combined alar base excision resulted in effective narrowing of the nasal base with elimination of excessive alar flare. Commonly feared complications, such as blunting of the alar-facial crease or notching of the alar rim, were avoided by using simple modifications in the technique of excision and closure.

  7. Pre-analytic and analytic sources of variations in thiopurine methyltransferase activity measurement in patients prescribed thiopurine-based drugs: A systematic review.

    PubMed

    Loit, Evelin; Tricco, Andrea C; Tsouros, Sophia; Sears, Margaret; Ansari, Mohammed T; Booth, Ronald A

    2011-07-01

    Low thiopurine S-methyltransferase (TPMT) enzyme activity is associated with increased thiopurine drug toxicity, particularly myelotoxicity. Pre-analytic and analytic variables for TPMT genotype and phenotype (enzyme activity) testing were reviewed. A systematic literature review was performed, and diagnostic laboratories were surveyed. Thirty-five studies reported relevant data for pre-analytic variables (patient age, gender, race, hematocrit, co-morbidity, co-administered drugs and specimen stability) and thirty-three for analytic variables (accuracy, reproducibility). TPMT is stable in blood when stored for up to 7 days at room temperature, and 3 months at -30°C. Pre-analytic patient variables do not affect TPMT activity. Fifteen drugs studied to date exerted no clinically significant effects in vivo. Enzymatic assay is the preferred technique. Radiochemical and HPLC techniques had intra- and inter-assay coefficients of variation (CVs) below 10%. TPMT is a stable enzyme, and its assay is not affected by age, gender, race or co-morbidity. Copyright © 2011. Published by Elsevier Inc.

  8. Single-step Reagentless Laser Scribing Fabrication of Electrochemical Paper-based Analytical Devices.

    PubMed

    de Araujo, William Reis; Frasson, Carolina M R; Ameku, Wilson A; Silva, José R; Angnes, Lúcio; Paixão, Thiago Rlc

    2017-10-05

    Herein we describe the use of a single-step laser scribing process to pattern nanostructured electrodes on paper-based devices. This facile and low-cost technique eliminates the need for chemical reagents or controlled conditions. Our process involves the use of a CO2 laser to pyrolyze the surface of the paperboard, producing a conductive porous non-graphitizing carbon material composed of graphene sheets and composites with aluminosilicate nanoparticles. The new electrode material was extensively characterized, and it exhibited high conductivity and an enhanced of active/geometric area ratio, because of which it was well suited for electrochemical purposes. Hence, as proof-of-concept, the devices were successfully employed for different analytical applications in the clinical, pharmaceutical, food, and forensic fields. The scalable and green fabrication method associated with the features of the new material is highly promising for the development of portable electrochemical devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Sensor Based on Aptamer Folding to Detect Low-Molecular Weight Analytes.

    PubMed

    Osypova, Alina; Thakar, Dhruv; Dejeu, Jérôme; Bonnet, Hugues; Van der Heyden, Angéline; Dubacheva, Galina V; Richter, Ralf P; Defrancq, Eric; Spinelli, Nicolas; Coche-Guérente, Liliane; Labbé, Pierre

    2015-08-04

    Aptamers have emerged as promising biorecognition elements in the development of biosensors. The present work focuses on the application of quartz crystal microbalance with dissipation monitoring (QCM-D) for the enantioselective detection of a low molecular weight target molecule (less than 200 Da) by aptamer-based sensors. While QCM-D is a powerful technique for label-free, real-time characterization and quantification of molecular interactions at interfaces, the detection of small molecules interacting with immobilized receptors still remains a challenge. In the present study, we take advantage of the aptamer conformational changes upon the target binding that induces displacement of water acoustically coupled to the sensing layer. As a consequence, this phenomenon leads to a significant enhancement of the detection signal. The methodology is exemplified with the enantioselective recognition of a low molecular weight model compound, L-tyrosinamide (L-Tym). QCM-D monitoring of L-Tym interaction with the aptamer monolayer leads to an appreciable signal that can be further exploited for analytical purposes or thermodynamics studies. Furthermore, in situ combination of QCM-D with spectroscopic ellipsometry unambiguously demonstrates that the conformational change induces a nanometric decrease of the aptamer monolayer thickness. Since QCM-D is sensitive to the whole mass of the sensing layer including water that is acoustically coupled, a decrease in thickness of the highly hydrated aptamer layer induces a sizable release of water that can be easily detected by QCM-D.

  10. A Microfluidic Paper-Based Analytical Device for Rapid Quantification of Particulate Chromium

    PubMed Central

    Rattanarat, Poomrat; Dungchai, Wijitar; Cate, David M.; Siangproh, Weena; Volckens, John; Chailapakul, Orawon; Henry, Charles S.

    2013-01-01

    Occupational exposure to Cr is concerning because of its myriad of health effects. Assessing chromium exposure is also cost and resource intensive because the analysis typically uses sophisticated instrumental techniques like Inductively-Coupled Plasma-Mass Spectrometry (ICP-MS). Here, we report a novel, simple, inexpensive microfluidic paper-based analytical device (µPAD) for measuring total Cr in airborne particulate matter. In the µPAD, tetravalent cerium (Ce(IV)) was used in a pretreatment zone to oxidize all soluble Cr to Cr(VI). After elution to the detection zone, Cr(VI) reacts with 1,5-diphenylcarbazide (1,5- DPC) forming 1,5-diphenylcarbazone (DPCO) and Cr(III). The resulting Cr(III) forms a distinct purple colored complex with the DPCO. As proof-of-principle, particulate matter (PM) collected on a sample filter was analyzed with the µPAD to quantify the mass of total Cr. A log-linear working range (0.23–3.75 µg; r2=0.998) between Cr and color intensity was obtained with a detection limit of 0.12 µg. For validation, a certified reference containing multiple competing metals was analyzed. Quantitative agreement was obtained between known Cr levels in the sample and the Cr measured using the µPAD. PMID:24120167

  11. Reliability-based structural optimization: A proposed analytical-experimental study

    NASA Technical Reports Server (NTRS)

    Stroud, W. Jefferson; Nikolaidis, Efstratios

    1993-01-01

    An analytical and experimental study for assessing the potential of reliability-based structural optimization is proposed and described. In the study, competing designs obtained by deterministic and reliability-based optimization are compared. The experimental portion of the study is practical because the structure selected is a modular, actively and passively controlled truss that consists of many identical members, and because the competing designs are compared in terms of their dynamic performance and are not destroyed if failure occurs. The analytical portion of this study is illustrated on a 10-bar truss example. In the illustrative example, it is shown that reliability-based optimization can yield a design that is superior to an alternative design obtained by deterministic optimization. These analytical results provide motivation for the proposed study, which is underway.

  12. Selection of a base serum for the preparation of quality control pools containing environmental analytes

    SciTech Connect

    Burse, V.W.; Korver, M.P.; McClure, P.M.; Phillips, D.L.; Head, S.L.; Miller, D.T. ); Buckley, D.J.; Nassif, J.; Timperi, R.J. )

    1992-01-01

    At two laboratories, an analytical method to determine polychlorinated biphenyls (PCBs) in serum was evaluated for its ability to recover in vitro-spiked PCBs from bovine and human serum. Statistically significant differences were found in the results obtained for the two matrices at both laboratories. Previously an interlaboratory bias between the laboratories of + 3.3% had been established by using bovine serum; however, with human serum the average interlaboratory bias was {minus}9.5% resulting in a change in absolute bias of approximately 13%. The analytes determined in the base materials before they were in vitro-spiked with PCBs were dichlorodiphenyldichloroethylene (p,p{prime}-DDE), PCBs, and serum lipids. The concentration of analytes and lipids was higher in base human serum than in base bovine serum.

  13. Selection of a base serum for the preparation of quality-control pools containing environment analytes

    SciTech Connect

    Burse, V.W.; Korver, M.P.; McClure, P.M.; Buckley, D.J.; Nassif, J.

    1992-01-01

    At two laboratories, an analytical method to determine polychlorinated biphenyls (PCBs) in serum was evaluated for its ability to recover in vitro-spiked PCBs from bovine and human serum. Statistically significant differences (p < 0.05) were found in the results obtained for the two matrices at both laboratories. Previously an interlaboratory bias between the laboratories of +3.3% had been established by using bovine serum; however, with human serum the average interlaboratory bias was -9.5% resulting in a change in absolute bias of approximately 13%. The analytes determined in the base materials before they were in vitro-spiked with PCBs were dichlorodiphenyldichloroethylene (p,p'-DDE), PCBs, and serum lipids (i.e., total cholesterol, triglycerides, free cholesterol and phospholipids). The concentration of analytes and lipids was higher in base human serum than in base bovine serum. (Copyright (c) 1992 by Marcel Dekker, Inc.)

  14. Applying knowledge compilation techniques to model-based reasoning

    NASA Technical Reports Server (NTRS)

    Keller, Richard M.

    1991-01-01

    Researchers in the area of knowledge compilation are developing general purpose techniques for improving the efficiency of knowledge-based systems. In this article, an attempt is made to define knowledge compilation, to characterize several classes of knowledge compilation techniques, and to illustrate how some of these techniques can be applied to improve the performance of model-based reasoning systems.

  15. Development of a fast analytical tool to identify oil spillages employing infrared spectral indexes and pattern recognition techniques.

    PubMed

    Fresco-Rivera, P; Fernández-Varela, R; Gómez-Carracedo, M P; Ramírez-Villalobos, F; Prada, D; Muniategui, S; Andrade, J M

    2007-11-30

    A fast analytical tool based on attenuated total reflectance mid-IR spectrometry is presented to evaluate the origin of spilled hydrocarbons and to monitor their fate on the environment. Ten spectral band ratios are employed in univariate and multivariate studies (principal components analysis, cluster analysis, density functions - potential curves - and Kohonen self organizing maps). Two indexes monitor typical photooxidation processes, five are related to aromatic characteristics and three study aliphatic and branched chains. The case study considered here comprises 45 samples taken on beaches (from 2002 to 2005) after the Prestige carrier accident off the Galician coast and 104 samples corresponding to weathering studies deployed for the Prestige's fuel, four typical crude oils and a fuel oil. The univariate studies yield insightful views on the gross chemical evolution whereas the multivariate studies allow for simple and straightforward elucidations on whether the unknown samples match the Prestige's fuel. Besides, a good differentiation on the weathering patterns of light and heavy products is obtained.

  16. State of practice and emerging application of analytical techniques of nuclear forensic analysis: highlights from the 4th Collaborative Materials Exercise of the Nuclear Forensics International Technical Working Group (ITWG)

    DOE PAGES

    Schwantes, Jon M.; Marsden, Oliva; Pellegrini, Kristi L.

    2016-09-16

    The Nuclear Forensics International Technical Working Group (ITWG) recently completed its fourth Collaborative Materials Exercise (CMX-4) in the 21 year history of the Group. This was also the largest materials exercise to date, with participating laboratories from 16 countries or international organizations. Moreover, exercise samples (including three separate samples of low enriched uranium oxide) were shipped as part of an illicit trafficking scenario, for which each laboratory was asked to conduct nuclear forensic analyses in support of a fictitious criminal investigation. In all, over 30 analytical techniques were applied to characterize exercise materials, for which ten of those techniques weremore » applied to ITWG exercises for the first time. We performed an objective review of the state of practice and emerging application of analytical techniques of nuclear forensic analysis based upon the outcome of this most recent exercise is provided.« less

  17. State of practice and emerging application of analytical techniques of nuclear forensic analysis: highlights from the 4th Collaborative Materials Exercise of the Nuclear Forensics International Technical Working Group (ITWG)

    SciTech Connect

    Schwantes, Jon M.; Marsden, Oliva; Pellegrini, Kristi L.

    2016-09-16

    The Nuclear Forensics International Technical Working Group (ITWG) recently completed its fourth Collaborative Materials Exercise (CMX-4) in the 21 year history of the Group. This was also the largest materials exercise to date, with participating laboratories from 16 countries or international organizations. Moreover, exercise samples (including three separate samples of low enriched uranium oxide) were shipped as part of an illicit trafficking scenario, for which each laboratory was asked to conduct nuclear forensic analyses in support of a fictitious criminal investigation. In all, over 30 analytical techniques were applied to characterize exercise materials, for which ten of those techniques were applied to ITWG exercises for the first time. We performed an objective review of the state of practice and emerging application of analytical techniques of nuclear forensic analysis based upon the outcome of this most recent exercise is provided.

  18. State of practice and emerging application of analytical techniques of nuclear forensic analysis: highlights from the 4th Collaborative Materials Exercise of the Nuclear Forensics International Technical Working Group (ITWG)

    SciTech Connect

    Schwantes, Jon M.; Marsden, Oliva; Pellegrini, Kristi L.

    2016-09-16

    The Nuclear Forensics International Technical Working Group (ITWG) recently completed its fourth Collaborative Materials Exercise (CMX-4) in the 21 year history of the Group. This was also the largest materials exercise to date, with participating laboratories from 16 countries or international organizations. Moreover, exercise samples (including three separate samples of low enriched uranium oxide) were shipped as part of an illicit trafficking scenario, for which each laboratory was asked to conduct nuclear forensic analyses in support of a fictitious criminal investigation. In all, over 30 analytical techniques were applied to characterize exercise materials, for which ten of those techniques were applied to ITWG exercises for the first time. We performed an objective review of the state of practice and emerging application of analytical techniques of nuclear forensic analysis based upon the outcome of this most recent exercise is provided.

  19. A smog chamber comparison of a microfluidic derivatisation measurement of gas-phase glyoxal and methylglyoxal with other analytical techniques

    NASA Astrophysics Data System (ADS)

    Pang, X.; Lewis, A. C.; Rickard, A. R.; Baeza-Romero, M. T.; Adams, T. J.; Ball, S. M.; Daniels, M. J. S.; Goodall, I. C. A.; Monks, P. S.; Peppe, S.; Ródenas García, M.; Sánchez, P.; Muñoz, A.

    2014-02-01

    A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o-(2, 3, 4, 5, 6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation reagent and a microfabricated planar glass micro-reactor comprising an inlet, gas and fluid splitting and combining channels, mixing junctions, and a heated capillary reaction microchannel. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the micro-reactor resulted in a fast and highly efficient derivatisation reaction, generating an effluent stream ready for direct introduction to a gas chromatograph-mass spectrometer (GC-MS). A linear response for GLY was observed over a calibration range 0.7 to 400 ppbV, and for MGLY of 1.2 to 300 ppbV, when derivatised under optimal reaction conditions. The analytical performance shows good accuracy (6.6% for GLY and 7.5% for MGLY), suitable precision (<12.0%) with method detection limits (MDLs) of 75 pptV for GLY and 185 pptV for MGLY, with a time resolution of 30 min. These MDLs are below or close to typical concentrations of these compounds observed in ambient air. The feasibility of the technique was assessed by applying the methodology to quantify α-dicarbonyls formed during the photo-oxidation of isoprene in the EUPHORE chamber. Good correlations were found between microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR) with a correlation coefficient (r2) of 0.84, Broadband Cavity Enhanced Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro extraction (SPME) (r2 = 0.89), and a photochemical chamber box modelling calculation (r2 = 0.79) for GLY measurements. For MGLY measurements, the microfluidic technique showed good agreement with BBCEAS (r2 = 0.87), SPME (r2 = 0.76), and the modeling simulation (r2 = 0.83), FTIR

  20. Flood alert system based on bayesian techniques

    NASA Astrophysics Data System (ADS)

    Gulliver, Z.; Herrero, J.; Viesca, C.; Polo, M. J.

    2012-04-01

    The problem of floods in the Mediterranean regions is closely linked to the occurrence of torrential storms in dry regions, where even the water supply relies on adequate water management. Like other Mediterranean basins in Southern Spain, the Guadalhorce River Basin is a medium sized watershed (3856 km2) where recurrent yearly floods occur , mainly in autumn and spring periods, driven by cold front phenomena. The torrential character of the precipitation in such small basins, with a concentration time of less than 12 hours, produces flash flood events with catastrophic effects over the city of Malaga (600000 inhabitants). From this fact arises the need for specific alert tools which can forecast these kinds of phenomena. Bayesian networks (BN) have been emerging in the last decade as a very useful and reliable computational tool for water resources and for the decision making process. The joint use of Artificial Neural Networks (ANN) and BN have served us to recognize and simulate the two different types of hydrological behaviour in the basin: natural and regulated. This led to the establishment of causal relationships between precipitation, discharge from upstream reservoirs, and water levels at a gauging station. It was seen that a recurrent ANN model working at an hourly scale, considering daily precipitation and the two previous hourly values of reservoir discharge and water level, could provide R2 values of 0.86. BN's results slightly improve this fit, but contribute with uncertainty to the prediction. In our current work to Design a Weather Warning Service based on Bayesian techniques the first steps were carried out through an analysis of the correlations between the water level and rainfall at certain representative points in the basin, along with the upstream reservoir discharge. The lower correlation found between precipitation and water level emphasizes the highly regulated condition of the stream. The autocorrelations of the variables were also

  1. Refractive index sensor based on photonic crystal fiber: effect of analyte channel diameter

    NASA Astrophysics Data System (ADS)

    Lopez-Bautista, Maria C.; Martynyuk, Alexander E.; Khotiaintsev, Sergei

    2017-01-01

    We analyzed the resonant coupling in the low-refractive-index sensor based on a directional coupler implemented in a microstructured optical fiber with a composite core and the parallel analyte channel in the form of a hollow-core waveguide. We showed the possibility of an 8-fold increase in the analyte channel radius that is equivalent to a 64-fold increase in its cross section, in comparison to the existing design. With an increase in the analyte channel radius, the resonance frequencies of the composite core mode and the satellite waveguide modes shift to longer wavelengths, while the dispersion curves of the high-order modes of the satellite waveguide tend to merge and their resonances become less pronounced than the resonances of the low-order modes. With an increase in the analyte channel radius from 2 to 16 μm, the sensor sensitivity increases by 40% and the detection limit becomes lower by a factor of 2. Such an increase in the analyte channel radius also eliminates the need in a high-pressure pump for filling the channel with analyte and thus makes this sensor much more practical than was previously thought.

  2. Steady-state protein focusing in carrier ampholyte based isoelectric focusing: Part I-Analytical solution.

    PubMed

    Shim, Jaesool; Yoo, Kisoo; Dutta, Prashanta

    2017-03-01

    The determination of an analytical solution to find the steady-state protein concentration distribution in IEF is very challenging due to the nonlinear coupling between mass and charge conservation equations. In this study, approximate analytical solutions are obtained for steady-state protein distribution in carrier ampholyte based IEF. Similar to the work of Svensson, the final concentration profile for proteins is assumed to be Gaussian, but appropriate expressions are presented in order to obtain the effective electric field and pH gradient in the focused protein band region. Analytical results are found from iterative solutions of a system of coupled algebraic equations using only several iterations for IEF separation of three plasma proteins: albumin, cardiac troponin I, and hemoglobin. The analytical results are compared with numerically predicted results for IEF, showing excellent agreement. Analytically obtained electric field and ionic conductivity distributions show significant deviation from their nominal values, which is essential in finding the protein focusing behavior at isoelectric points. These analytical solutions can be used to determine steady-state protein concentration distribution for experiment design of IEF considering any number of proteins and ampholytes. Moreover, the model presented herein can be used to find the conductivity, electric field, and pH field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. The Ophidia framework: toward cloud-based data analytics for climate change

    NASA Astrophysics Data System (ADS)

    Fiore, Sandro; D'Anca, Alessandro; Elia, Donatello; Mancini, Marco; Mariello, Andrea; Mirto, Maria; Palazzo, Cosimo; Aloisio, Giovanni

    2015-04-01

    The Ophidia project is a research effort on big data analytics facing scientific data analysis challenges in the climate change domain. It provides parallel (server-side) data analysis, an internal storage model and a hierarchical data organization to manage large amount of multidimensional scientific data. The Ophidia analytics platform provides several MPI-based parallel operators to manipulate large datasets (data cubes) and array-based primitives to perform data analysis on large arrays of scientific data. The most relevant data analytics use cases implemented in national and international projects target fire danger prevention (OFIDIA), interactions between climate change and biodiversity (EUBrazilCC), climate indicators and remote data analysis (CLIP-C), sea situational awareness (TESSA), large scale data analytics on CMIP5 data in NetCDF format, Climate and Forecast (CF) convention compliant (ExArch). Two use cases regarding the EU FP7 EUBrazil Cloud Connect and the INTERREG OFIDIA projects will be presented during the talk. In the former case (EUBrazilCC) the Ophidia framework is being extended to integrate scalable VM-based solutions for the management of large volumes of scientific data (both climate and satellite data) in a cloud-based environment to study how climate change affects biodiversity. In the latter one (OFIDIA) the data analytics framework is being exploited to provide operational support regarding processing chains devoted to fire danger prevention. To tackle the project challenges, data analytics workflows consisting of about 130 operators perform, among the others, parallel data analysis, metadata management, virtual file system tasks, maps generation, rolling of datasets, import/export of datasets in NetCDF format. Finally, the entire Ophidia software stack has been deployed at CMCC on 24-nodes (16-cores/node) of the Athena HPC cluster. Moreover, a cloud-based release tested with OpenNebula is also available and running in the private

  4. Long base line interferometry: a new technique.

    PubMed

    Broten, N W; Legg, T H; Locke, J L; McLeish, C W; Richards, R S; Chisholm, R M; Gush, H P; Yen, J L; Galt, J A

    1967-06-23

    The technique of using magnetic-tape recorders and atomic frequency standards to operate two widely separated radio telescopes as a phase-coherent interferometer when the stations have no radio-frequency connecting link has been successfully tested at the National Research Council of Canada's Algonquin Radio Observatory.

  5. Characterization of the Aerosol-based Synthesis of Uranium Particles as a Potential Reference Material for Micro Analytical Methods.

    PubMed

    Middendorp, Ronald; Dürr, Martin; Knott, Alexander; Pointurier, Fabien; Ferreira Sanchez, Dario; Samson, Valerie Ann; Grolimund, Daniel

    2017-03-27

    A process for production of micrometer-sized particles composed of uranium oxide using aerosol spray pyrolysis is characterized with respect to the various production parameters. The aerosol is generated using a vibrating orifice aerosol generator providing monodisperse droplets, which are oxidized in a subsequent heat treatment. The final particles are characterized with micro analytical methods to determine size, shape, internal morphology, chemical and structural properties in order to assess the suitability of the produced particles as a reference material for micro analytical methods, in particular for mass-spectrometry. It is demonstrated that physico-chemical processes during particle formation and the heat treatment to chemically transform particles into an oxide strongly influence the particle shape and the internal morphology. Synchrotron μ-X-ray based techniques combined with μ-Raman spectroscopy have been applied to demonstrate that the obtained micro particles consist of a triuranium octoxide phase. Our studies demonstrate that the process is capable of delivering spherical particles with determined uniform size and ele-mental as well as chemical composition. The particles therefore represent a suitable base material to fulfill the homogeneity and stability requirements of a reference material for micro analytical methods applied in, for example, international safeguards or nuclear forensics.

  6. Simultaneous determination of antazoline and naphazoline by the net analyte signal standard addition method and spectrophotometric technique.

    PubMed

    Asadpour-Zeynali, Karim; Ghavami, Raoof; Esfandiari, Roghayeh; Soheili-Azad, Payam

    2010-01-01

    A novel net analyte signal standard addition method (NASSAM) was used for simultaneous determination of the drugs anthazoline and naphazoline. The NASSAM can be applied for determination of analytes in the presence of known interferents. The proposed method is used to eliminate the calibration and prediction steps of multivariate calibration methods; the determination is carried out in a single step for each analyte. The accuracy of the predictions against the H-point standard addition method is independent of the shape of the analyte and interferent spectra. The net analyte signal concept was also used to calculate multivariate analytical figures of merit, such as LOD, selectivity, and sensitivity. The method was successfully applied to the simultaneous determination of anthazoline and naphazoline in a commercial eye drop sample.

  7. Chemometric experimental design based optimization techniques in capillary electrophoresis: a critical review of modern applications.

    PubMed

    Hanrahan, Grady; Montes, Ruthy; Gomez, Frank A

    2008-01-01

    A critical review of recent developments in the use of chemometric experimental design based optimization techniques in capillary electrophoresis applications is presented. Current advances have led to enhanced separation capabilities of a wide range of analytes in such areas as biological, environmental, food technology, pharmaceutical, and medical analysis. Significant developments in design, detection methodology and applications from the last 5 years (2002-2007) are reported. Furthermore, future perspectives in the use of chemometric methodology in capillary electrophoresis are considered.

  8. Creating analytically divergence-free velocity fields from grid-based data

    NASA Astrophysics Data System (ADS)

    Ravu, Bharath; Rudman, Murray; Metcalfe, Guy; Lester, Daniel R.; Khakhar, Devang V.

    2016-10-01

    We present a method, based on B-splines, to calculate a C2 continuous analytic vector potential from discrete 3D velocity data on a regular grid. A continuous analytically divergence-free velocity field can then be obtained from the curl of the potential. This field can be used to robustly and accurately integrate particle trajectories in incompressible flow fields. Based on the method of Finn and Chacon (2005) [10] this new method ensures that the analytic velocity field matches the grid values almost everywhere, with errors that are two to four orders of magnitude lower than those of existing methods. We demonstrate its application to three different problems (each in a different coordinate system) and provide details of the specifics required in each case. We show how the additional accuracy of the method results in qualitatively and quantitatively superior trajectories that results in more accurate identification of Lagrangian coherent structures.

  9. Effects of Mountain Ultra-Marathon Running on ROS Production and Oxidative Damage by Micro-Invasive Analytic Techniques

    PubMed Central

    Mrakic-Sposta, Simona; Gussoni, Maristella; Moretti, Sarah; Pratali, Lorenza; Giardini, Guido; Tacchini, Philippe; Dellanoce, Cinzia; Tonacci, Alessandro; Mastorci, Francesca; Borghini, Andrea; Montorsi, Michela; Vezzoli, Alessandra

    2015-01-01

    Purpose Aiming to gain a detailed insight into the physiological mechanisms involved under extreme conditions, a group of experienced ultra-marathon runners, performing the mountain Tor des Géants® ultra-marathon: 330 km trail-run in Valle d’Aosta, 24000 m of positive and negative elevation changes, was monitored. ROS production rate, antioxidant capacity, oxidative damage and inflammation markers were assessed, adopting micro-invasive analytic techniques. Methods Forty-six male athletes (45.04±8.75 yr, 72.6±8.4 kg, 1.76±0.05 m) were tested. Capillary blood and urine were collected before (Pre-), in the middle (Middle-) and immediately after (Post-) Race. Samples were analyzed for: Reactive Oxygen Species (ROS) production by Electron Paramagnetic Resonance; Antioxidant Capacity by Electrochemistry; oxidative damage (8-hydroxy-2-deoxy Guanosine: 8-OH-dG; 8-isoprostane: 8-isoPGF2α) and nitric oxide metabolites by enzymatic assays; inflammatory biomarkers (plasma and urine interleukin-6: IL-6-P and IL-6-U) by enzyme-linked immunosorbent assays (ELISA); Creatinine and Neopterin by HPLC, hematologic (lactate, glucose and hematocrit) and urine parameters by standard analyses. Results Twenty-five athletes finished the race, while twenty-one dropped out of it. A significant increase (Post-Race vs Pre) of the ROS production rate (2.20±0.27 vs 1.65±0.22 μmol.min-1), oxidative damage biomarkers (8-OH-dG: 6.32±2.38 vs 4.16±1.25 ng.mg-1 Creatinine and 8-isoPGF2α: 1404.0±518.30 vs 822.51±448.91 pg.mg-1Creatinine), inflammatory state (IL-6-P: 66.42±36.92 vs 1.29±0.54 pg.mL-1 and IL-6-U: 1.33±0.56 vs 0.71±0.17 pg.mL1) and lactate production (+190%), associated with a decrease of both antioxidant capacity (-7%) and renal function (i.e. Creatinine level +76%) was found. Conclusions The used micro-invasive analytic methods allowed us to perform most of them before, during and immediately after the race directly in the field, by passing the need of storing and

  10. Surface plasmon resonance based biosensor technique: a review.

    PubMed

    Guo, Xiaowei

    2012-07-01

    Optical Surface plasmon resonance (SPR) biosensors represent the most advanced and developed optical label-free biosensor technology. Optical SPR biosensors are a powerful detection and analysis tool that has vast applications in environmental protection, biotechnology, medical diagnostics, drug screening, food safety and security. This article reviews the recent development of SPR biosensor techniques, including bulk SPR and localized SPR (LSPR) biosensors, for detecting interactions between an analyte of interest in solution and a biomolecular recognition. The concepts of bulk and localized SPs and the working principles of both sensing techniques are introduced. Major sensing advances on biorecognition elements, measurement formats, and sensing platforms are presented. Finally, the discussions on both biosensor techniques as well as comparison of both SPR sensing techniques are made.

  11. On Bitstream Based Edge Detection Techniques

    DTIC Science & Technology

    2009-01-01

    IEEE Transactions on, vol. 38, no. 1, pp. xviii– iv, Feb 1992. [5] Rafael C. Gonzalez and Richard E. Woods, Digital Image Processing, Addison-Wesley...Carmona-Poyato, R. Medina- Carnicer, and F. J. Madrid- Cuevas , “Automatic genera- tion of consensus ground truth for the comparison of edge detection techniques,” Image Vision Comput., vol. 26, no. 4, pp. 496–511, 2008.

  12. Parametric analysis and optimized torque characteristics of a coaxial magnetic gear based on the subdomain analytical model

    NASA Astrophysics Data System (ADS)

    Shin, Kyung-Hun; Park, Hyung-Il; Cho, Han-Wook; Choi, Jang-Young

    2017-05-01

    This paper presents the torque calculation and parametric analysis of a coaxial magnetic gear (CMG). We obtained analytical magnetic field solutions produced by permanent magnets based on a magnetic vector potential. Then, the analytical solutions for magnetic torque were obtained. All analytical results were extensively validated with nonlinear two-dimensional finite element analysis. Finally, using the derived analytical magnetic torque solutions, we carried out parametric analysis to determine the influence of the design parameters on the CMG's behavior.

  13. Efficiency of analytical and sampling-based uncertainty propagation in intensity-modulated proton therapy.

    PubMed

    Wahl, N; Hennig, P; Wieser, H P; Bangert, M

    2017-06-26

    The sensitivity of intensity-modulated proton therapy (IMPT) treatment plans to uncertainties can be quantified and mitigated with robust/min-max and stochastic/probabilistic treatment analysis and optimization techniques. Those methods usually rely on sparse random, importance, or worst-case sampling. Inevitably, this imposes a trade-off between computational speed and accuracy of the uncertainty propagation. Here, we investigate analytical probabilistic modeling (APM) as an alternative for uncertainty propagation and minimization in IMPT that does not rely on scenario sampling. APM propagates probability distributions over range and setup uncertainties via a Gaussian pencil-beam approximation into moments of the probability distributions over the resulting dose in closed form. It supports arbitrary correlation models and allows for efficient incorporation of fractionation effects regarding random and systematic errors. We evaluate the trade-off between run-time and accuracy of APM uncertainty computations on three patient datasets. Results are compared against reference computations facilitating importance and random sampling. Two approximation techniques to accelerate uncertainty propagation and minimization based on probabilistic treatment plan optimization are presented. Runtimes are measured on CPU and GPU platforms, dosimetric accuracy is quantified in comparison to a sampling-based benchmark (5000 random samples). APM accurately propagates range and setup uncertainties into dose uncertainties at competitive run-times (GPU [Formula: see text] min). The resulting standard deviation (expectation value) of dose show average global [Formula: see text] pass rates between 94.2% and 99.9% (98.4% and 100.0%). All investigated importance sampling strategies provided less accuracy at higher run-times considering only a single fraction. Considering fractionation, APM uncertainty propagation and treatment plan optimization was proven to be possible at constant time

  14. Efficiency of analytical and sampling-based uncertainty propagation in intensity-modulated proton therapy

    NASA Astrophysics Data System (ADS)

    Wahl, N.; Hennig, P.; Wieser, H. P.; Bangert, M.

    2017-07-01

    The sensitivity of intensity-modulated proton therapy (IMPT) treatment plans to uncertainties can be quantified and mitigated with robust/min-max and stochastic/probabilistic treatment analysis and optimization techniques. Those methods usually rely on sparse random, importance, or worst-case sampling. Inevitably, this imposes a trade-off between computational speed and accuracy of the uncertainty propagation. Here, we investigate analytical probabilistic modeling (APM) as an alternative for uncertainty propagation and minimization in IMPT that does not rely on scenario sampling. APM propagates probability distributions over range and setup uncertainties via a Gaussian pencil-beam approximation into moments of the probability distributions over the resulting dose in closed form. It supports arbitrary correlation models and allows for efficient incorporation of fractionation effects regarding random and systematic errors. We evaluate the trade-off between run-time and accuracy of APM uncertainty computations on three patient datasets. Results are compared against reference computations facilitating importance and random sampling. Two approximation techniques to accelerate uncertainty propagation and minimization based on probabilistic treatment plan optimization are presented. Runtimes are measured on CPU and GPU platforms, dosimetric accuracy is quantified in comparison to a sampling-based benchmark (5000 random samples). APM accurately propagates range and setup uncertainties into dose uncertainties at competitive run-times (GPU ≤slant {5} min). The resulting standard deviation (expectation value) of dose show average global γ{3% / {3}~mm} pass rates between 94.2% and 99.9% (98.4% and 100.0%). All investigated importance sampling strategies provided less accuracy at higher run-times considering only a single fraction. Considering fractionation, APM uncertainty propagation and treatment plan optimization was proven to be possible at constant time complexity

  15. An Analytical Technique to Elucidate Field Impurities From Manufacturing Uncertainties of an Double Pancake Type HTS Insert for High Field LTS/HTS NMR Magnets.

    PubMed

    Hahn, Seung-Yong; Ahn, Min Cheol; Bobrov, Emanuel Saul; Bascuñán, Juan; Iwasa, Yukikazu

    2009-06-01

    This paper addresses adverse effects of dimensional uncertainties of an HTS insert assembled with double-pancake coils on spatial field homogeneity. Each DP coil was wound with Bi2223 tapes having dimensional tolerances larger than one order of magnitude of those accepted for LTS wires used in conventional NMR magnets. The paper presents: 1) dimensional variations measured in two LTS/HTS NMR magnets, 350 MHz (LH350) and 700 MHz (LH700), both built and operated at the Francis Bitter Magnet Laboratory; and 2) an analytical technique and its application to elucidate the field impurities measured with the two LTS/HTS magnets. Field impurities computed with the analytical model and those measured with the two LTS/HTS magnets agree quite well, demonstrating that this analytical technique is applicable to design a DP-assembled HTS insert with an improved field homogeneity for a high-field LTS/HTS NMR magnet.

  16. An Analytical Technique to Elucidate Field Impurities From Manufacturing Uncertainties of an Double Pancake Type HTS Insert for High Field LTS/HTS NMR Magnets

    PubMed Central

    Hahn, Seung-yong; Ahn, Min Cheol; Bobrov, Emanuel Saul; Bascuñán, Juan; Iwasa, Yukikazu

    2010-01-01

    This paper addresses adverse effects of dimensional uncertainties of an HTS insert assembled with double-pancake coils on spatial field homogeneity. Each DP coil was wound with Bi2223 tapes having dimensional tolerances larger than one order of magnitude of those accepted for LTS wires used in conventional NMR magnets. The paper presents: 1) dimensional variations measured in two LTS/HTS NMR magnets, 350 MHz (LH350) and 700 MHz (LH700), both built and operated at the Francis Bitter Magnet Laboratory; and 2) an analytical technique and its application to elucidate the field impurities measured with the two LTS/HTS magnets. Field impurities computed with the analytical model and those measured with the two LTS/HTS magnets agree quite well, demonstrating that this analytical technique is applicable to design a DP-assembled HTS insert with an improved field homogeneity for a high-field LTS/HTS NMR magnet. PMID:20407595

  17. Research and development of LANDSAT-based crop inventory techniques

    NASA Technical Reports Server (NTRS)

    Horvath, R.; Cicone, R. C.; Malila, W. A. (Principal Investigator)

    1982-01-01

    A wide spectrum of technology pertaining to the inventory of crops using LANDSAT without in situ training data is addressed. Methods considered include Bayesian based through-the-season methods, estimation technology based on analytical profile fitting methods, and expert-based computer aided methods. Although the research was conducted using U.S. data, the adaptation of the technology to the Southern Hemisphere, especially Argentina was considered.

  18. Island Explorations: Discovering Effects of Environmental Research-Based Lab Activities on Analytical Chemistry Students

    ERIC Educational Resources Information Center

    Tomasik, Janice Hall; LeCaptain, Dale; Murphy, Sarah; Martin, Mary; Knight, Rachel M.; Harke, Maureen A.; Burke, Ryan; Beck, Kara; Acevedo-Polakovich, I. David

    2014-01-01

    Motivating students in analytical chemistry can be challenging, in part because of the complexity and breadth of topics involved. Some methods that help encourage students and convey real-world relevancy of the material include incorporating environmental issues, research-based lab experiments, and service learning projects. In this paper, we…

  19. A structurally based analytic model for estimation of biomass and fuel loads of woodland trees

    Treesearch

    Robin J. Tausch

    2009-01-01

    Allometric/structural relationships in tree crowns are a consequence of the physical, physiological, and fluid conduction processes of trees, which control the distribution, efficient support, and growth of foliage in the crown. The structural consequences of these processes are used to develop an analytic model based on the concept of branch orders. A set of...

  20. Island Explorations: Discovering Effects of Environmental Research-Based Lab Activities on Analytical Chemistry Students

    ERIC Educational Resources Information Center

    Tomasik, Janice Hall; LeCaptain, Dale; Murphy, Sarah; Martin, Mary; Knight, Rachel M.; Harke, Maureen A.; Burke, Ryan; Beck, Kara; Acevedo-Polakovich, I. David

    2014-01-01

    Motivating students in analytical chemistry can be challenging, in part because of the complexity and breadth of topics involved. Some methods that help encourage students and convey real-world relevancy of the material include incorporating environmental issues, research-based lab experiments, and service learning projects. In this paper, we…

  1. Reliability Generalization of Curriculum-Based Measurement Reading Aloud: A Meta-Analytic Review

    ERIC Educational Resources Information Center

    Yeo, Seungsoo

    2011-01-01

    The purpose of this study was to employ the meta-analytic method of Reliability Generalization to investigate the magnitude and variability of reliability estimates obtained across studies using Curriculum-Based Measurement reading aloud. Twenty-eight studies that met the inclusion criteria were used to calculate the overall mean reliability of…

  2. Effects of Computer Based Learning on Students' Attitudes and Achievements towards Analytical Chemistry

    ERIC Educational Resources Information Center

    Akcay, Hüsamettin; Durmaz, Asli; Tüysüz, Cengiz; Feyzioglu, Burak

    2006-01-01

    The aim of this study was to compare the effects of computer-based learning and traditional method on students' attitudes and achievement towards analytical chemistry. Students from Chemistry Education Department at Dokuz Eylul University (D.E.U) were selected randomly and divided into three groups; two experimental (Eg-1 and Eg-2) and a control…

  3. Merging Old and New: An Instrumentation-Based Introductory Analytical Laboratory

    ERIC Educational Resources Information Center

    Jensen, Mark B.

    2015-01-01

    An instrumentation-based laboratory curriculum combining traditional unknown analyses with student-designed projects has been developed for an introductory analytical chemistry course. In the first half of the course, students develop laboratory skills and instrumental proficiency by rotating through six different instruments performing…

  4. The Effect of Brain Based Learning on Academic Achievement: A Meta-Analytical Study

    ERIC Educational Resources Information Center

    Gozuyesil, Eda; Dikici, Ayhan

    2014-01-01

    This study's aim is to measure the effect sizes of the quantitative studies that examined the effectiveness of brain-based learning on students' academic achievement and to examine with the meta-analytical method if there is a significant difference in effect in terms of the factors of education level, subject matter, sampling size, and the…

  5. Merging Old and New: An Instrumentation-Based Introductory Analytical Laboratory

    ERIC Educational Resources Information Center

    Jensen, Mark B.

    2015-01-01

    An instrumentation-based laboratory curriculum combining traditional unknown analyses with student-designed projects has been developed for an introductory analytical chemistry course. In the first half of the course, students develop laboratory skills and instrumental proficiency by rotating through six different instruments performing…

  6. Analytical Derivation: An Epistemic Game for Solving Mathematically Based Physics Problems

    ERIC Educational Resources Information Center

    Bajracharya, Rabindra R.; Thompson, John R.

    2016-01-01

    Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the "analytical derivation" game. This game involves deriving an…

  7. Reliability Generalization of Curriculum-Based Measurement Reading Aloud: A Meta-Analytic Review

    ERIC Educational Resources Information Center

    Yeo, Seungsoo

    2011-01-01

    The purpose of this study was to employ the meta-analytic method of Reliability Generalization to investigate the magnitude and variability of reliability estimates obtained across studies using Curriculum-Based Measurement reading aloud. Twenty-eight studies that met the inclusion criteria were used to calculate the overall mean reliability of…

  8. Effects of Computer Based Learning on Students' Attitudes and Achievements towards Analytical Chemistry

    ERIC Educational Resources Information Center

    Akcay, Husamettin; Durmaz, Asli; Tuysuz, Cengiz; Feyzioglu, Burak

    2006-01-01

    The aim of this study was to compare the effects of computer-based learning and traditional method on students' attitudes and achievement towards analytical chemistry. Students from Chemistry Education Department at Dokuz Eylul University (D.E.U) were selected randomly and divided into three groups; two experimental (Eg-1 and Eg-2) and a control…

  9. Enterprise Systems Value-Based R&D Portfolio Analytics: Methods, Processes, and Tools

    DTIC Science & Technology

    2014-01-14

    in database and data warehousing, data mining and machine learning, risk analysis and optimization, as well as applied analytics. Practitioners...analyzing historical time series data to provide insights regarding future decisions. • Data mining – which involves mining transactional data bases...reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of

  10. Analytical Derivation: An Epistemic Game for Solving Mathematically Based Physics Problems

    ERIC Educational Resources Information Center

    Bajracharya, Rabindra R.; Thompson, John R.

    2016-01-01

    Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the "analytical derivation" game. This game involves deriving an…

  11. Uses of Multivariate Analytical Techniques in Online and Blended Business Education: An Assessment of Current Practice and Recommendations for Future Research

    ERIC Educational Resources Information Center

    Arbaugh, J. B.; Hwang, Alvin

    2013-01-01

    Seeking to assess the analytical rigor of empirical research in management education, this article reviews the use of multivariate statistical techniques in 85 studies of online and blended management education over the past decade and compares them with prescriptions offered by both the organization studies and educational research communities.…

  12. Uses of Multivariate Analytical Techniques in Online and Blended Business Education: An Assessment of Current Practice and Recommendations for Future Research

    ERIC Educational Resources Information Center

    Arbaugh, J. B.; Hwang, Alvin

    2013-01-01

    Seeking to assess the analytical rigor of empirical research in management education, this article reviews the use of multivariate statistical techniques in 85 studies of online and blended management education over the past decade and compares them with prescriptions offered by both the organization studies and educational research communities.…

  13. Rapid and alternative fabrication method for microfluidic paper based analytical devices.

    PubMed

    Malekghasemi, Soheil; Kahveci, Enver; Duman, Memed

    2016-10-01

    A major application of microfluidic paper-based analytical devices (µPADs) includes the field of point-of-care (POC) diagnostics. It is important for POC diagnostics to possess properties such as ease-of-use and low cost. However, µPADs need multiple instruments and fabrication steps. In this study, two different chemicals (Hexamethyldisilazane and Tetra-ethylorthosilicate) were used, and three different methods (heating, plasma treatment, and microwave irradiation) were compared to develop µPADs. Additionally, an inkjet-printing technique was used for generating a hydrophilic channel and printing certain chemical agents on different regions of a modified filter paper. A rapid and effective fabrication method to develop µPADs within 10min was introduced using an inkjet-printing technique in conjunction with a microwave irradiation method. Environmental scanning electron microscope (ESEM) and x-ray photoelectron spectroscopy (XPS) were used for morphology characterization and determining the surface chemical compositions of the modified filter paper, respectively. Contact angle measurements were used to fulfill the hydrophobicity of the treated filter paper. The highest contact angle value (141°±1) was obtained using the microwave irradiation method over a period of 7min, when the filter paper was modified by TEOS. Furthermore, by using this method, the XPS results of TEOS-modified filter paper revealed Si2p (23%) and Si-O bounds (81.55%) indicating the presence of Si-O-Si bridges and Si(OEt) groups, respectively. The ESEM results revealed changes in the porous structures of the papers and decreases in the pore sizes. Washburn assay measurements tested the efficiency of the generated hydrophilic channels in which similar water penetration rates were observed in the TEOS-modified filter paper and unmodified (plain) filter paper. The validation of the developed µPADs was performed by utilizing the rapid urease test as a model test system. The detection limit of

  14. Liquid Tunable Microlenses based on MEMS techniques

    PubMed Central

    Zeng, Xuefeng; Jiang, Hongrui

    2013-01-01

    The recent rapid development in microlens technology has provided many opportunities for miniaturized optical systems, and has found a wide range of applications. Of these microlenses, tunable-focus microlenses are of special interest as their focal lengths can be tuned using micro-scale actuators integrated with the lens structure. Realization of such tunable microlens generally relies on the microelectromechanical system (MEMS) technologies. Here, we review the recent progress in tunable liquid microlenses. The underlying physics relevant to these microlenses are first discussed, followed by description of three main categories of tunable microlenses involving MEMS techniques, mechanically driven, electrically driven, and those integrated within microfluidic systems. PMID:24163480

  15. PIE: A Dynamic Failure-Based Technique

    NASA Technical Reports Server (NTRS)

    Voas, Jeffrey M.

    1990-01-01

    This paper presents a dynamic technique for statistically estimating three program characteristics that affect a program's computational behavior: (1) the probability that a particular section of a program is executed, (2) the probability that the particular section affects the data state, and (3) the probability that a data state produced by that section has an effect on program output. These three characteristics can be used to predict whether faults are likely to be uncovered by software testing. Index Terms: Software testing, data state, fault, failure, testability. 1 Introduction

  16. Nanostructured silicon-based biosensors for the selective identification of analytes of social interest

    NASA Astrophysics Data System (ADS)

    D'Auria, Sabato; de Champdoré, Marcella; Aurilia, Vincenzo; Parracino, Antonietta; Staiano, Maria; Vitale, Annalisa; Rossi, Mosè; Rea, Ilaria; Rotiroti, Lucia; Rossi, Andrea M.; Borini, Stefano; Rendina, Ivo; DeStefano, Luca

    2006-08-01

    Small analytes such as glucose, L-glutamine (Gln), and ammonium nitrate are detected by means of optical biosensors based on a very common nanostructured material, porous silicon (PSi). Specific recognition elements, such as protein receptors and enzymes, were immobilized on hydrogenated PSi wafers and used as probes in optical sensing systems. The binding events were optically transduced as wavelength shifts of the porous silicon reflectivity spectrum or were monitored via changes of the fluorescence emission. The biosensors described in this article suggest a general approach for the development of new sensing systems for a wide range of analytes of high social interest.

  17. Nondestructive atomic compositional analysis of BeMgZnO quaternary alloys using ion beam analytical techniques

    NASA Astrophysics Data System (ADS)

    Zolnai, Z.; Toporkov, M.; Volk, J.; Demchenko, D. O.; Okur, S.; Szabó, Z.; Özgür, Ü.; Morkoç, H.; Avrutin, V.; Kótai, E.

    2015-02-01

    The atomic composition with less than 1-2 atom% uncertainty was measured in ternary BeZnO and quaternary BeMgZnO alloys using a combination of nondestructive Rutherford backscattering spectrometry with 1 MeV He+ analyzing ion beam and non-Rutherford elastic backscattering experiments with 2.53 MeV energy protons. An enhancement factor of 60 in the cross-section of Be for protons has been achieved to monitor Be atomic concentrations. Usually the quantitative analysis of BeZnO and BeMgZnO systems is challenging due to difficulties with appropriate experimental tools for the detection of the light Be element with satisfactory accuracy. As it is shown, our applied ion beam technique, supported with the detailed simulation of ion stopping, backscattering, and detection processes allows of quantitative depth profiling and compositional analysis of wurtzite BeZnO/ZnO/sapphire and BeMgZnO/ZnO/sapphire layer structures with low uncertainty for both Be and Mg. In addition, the excitonic bandgaps of the layers were deduced from optical transmittance measurements. To augment the measured compositions and bandgaps of BeO and MgO co-alloyed ZnO layers, hybrid density functional bandgap calculations were performed with varying the Be and Mg contents. The theoretical vs. experimental bandgaps show linear correlation in the entire bandgap range studied from 3.26 eV to 4.62 eV. The analytical method employed should help facilitate bandgap engineering for potential applications, such as solar blind UV photodetectors and heterostructures for UV emitters and intersubband devices.

  18. Using Analytic Techniques to Resolve Numerical Issues in a Pseudo Spectral Solver for a Black Hole Scalar Field

    NASA Astrophysics Data System (ADS)

    Munro, Eugene

    2013-12-01

    In this paper, we will solve the Hamiltonian constraint describing a curved general relativistic spacetime to find initial data describing how a black hole exists in vacuum. This has been done before by other researchers [Ansorg, 2004], and we will be adapting our own methods to an existing pseudo spectral Poisson solver [Gourgoulhon, 2001]. The need for this adaptation arises from improper numerical handling, done by pseudo spectral-methods, of a large part the Hamiltonian constraint equation due to the presence of the black hole singularity. To resolve a portion of this issue up to a given order, we will determine irregularities by executing a polynomial expansion on the Hamiltonian constraint, analytically solving the troublesome components of the equation and subtracting those out of the numerical process. This technique will increase the equation's differentiability and allow the numerical solver to run more efficiently. We will cover all the calculations needed to describe one black hole with arbitrary spin and linear momentum. Our process is easily expanded into cases with n black holes [Brandt, 1997], which we will show in chapter 2. We will implement a spherical harmonic decomposition of the black hole conformal factor, using them as basis functions by which to further expand and dissect the Hamiltonian Constraint equation. In the end, the expansion and subtraction method will be done out to the order of r4, where r is the spherical radius assuming the black hole is at the coordinate origin, making the Hamiltonian equation, which, unaltered, is a C 2 equation, become a C7 equation. Smoothing the Hamiltonian improves numerical precision, especially near the BH where the most interesting physics occurs. The method used in this paper can be further implemented to higher orders of r to yield even smoother conditions. We will test the numerical results of using this method against the existing solver that uses the publicly available Lorene numerical libraries

  19. Aptamer- and nucleic acid enzyme-based systems for simultaneous detection of multiple analytes

    DOEpatents

    Lu, Yi [Champaign, IL; Liu, Juewen [Albuquerque, NM

    2011-11-15

    The present invention provides aptamer- and nucleic acid enzyme-based systems for simultaneously determining the presence and optionally the concentration of multiple analytes in a sample. Methods of utilizing the system and kits that include the sensor components are also provided. The system includes a first reactive polynucleotide that reacts to a first analyte; a second reactive polynucleotide that reacts to a second analyte; a third polynucleotide; a fourth polynucleotide; a first particle, coupled to the third polynucleotide; a second particle, coupled to the fourth polynucleotide; and at least one quencher, for quenching emissions of the first and second quantum dots, coupled to the first and second reactive polynucleotides. The first particle includes a quantum dot having a first emission wavelength. The second particle includes a second quantum dot having a second emission wavelength different from the first emission wavelength. The third polynucleotide and the fourth polynucleotide are different.

  20. Acid-base titrations using microfluidic paper-based analytical devices.

    PubMed

    Karita, Shingo; Kaneta, Takashi

    2014-12-16

    Rapid and simple acid-base titration was accomplished using a novel microfluidic paper-based analytical device (μPAD). The μPAD was fabricated by wax printing and consisted of ten reservoirs for reaction and detection. The reaction reservoirs contained various amounts of a primary standard substance, potassium hydrogen phthalate (KHPth), whereas a constant amount of phenolphthalein was added to all the detection reservoirs. A sample solution containing NaOH was dropped onto the center of the μPAD and was allowed to spread to the reaction reservoirs where the KHPth neutralized it. When the amount of NaOH exceeded that of the KHPth in the reaction reservoirs, unneutralized hydroxide ion penetrated the detection reservoirs, resulting in a color reaction from the phenolphthalein. Therefore, the number of the detection reservoirs with no color change determined the concentration of the NaOH in the sample solution. The titration was completed within 1 min by visually determining the end point, which required neither instrumentation nor software. The volumes of the KHPth and phenolphthalein solutions added to the corresponding reservoirs were optimized to obtain reproducible and accurate results for the concentration of NaOH. The μPADs determined the concentration of NaOH at orders of magnitude ranging from 0.01 to 1 M. An acid sample, HCl, was also determined using Na2CO3 as a primary standard substance instead of KHPth. Furthermore, the μPAD was applicable to the titrations of nitric acid, sulfuric acid, acetic acid, and ammonia solutions. The μPADs were stable for more than 1 month when stored in darkness at room temperature, although this was reduced to only 5 days under daylight conditions. The analysis of acidic hot spring water was also demonstrated in the field using the μPAD, and the results agreed well with those obtained by classic acid-base titration.

  1. Noise-immune cavity-enhanced analytical atomic spectrometry - NICE-AAS - A technique for detection of elements down to zeptogram amounts

    NASA Astrophysics Data System (ADS)

    Axner, Ove; Ehlers, Patrick; Hausmaninger, Thomas; Silander, Isak; Ma, Weiguang

    2014-10-01

    Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) is a powerful technique for detection of molecular compounds in gas phase that is based on a combination of two important concepts: frequency modulation spectroscopy (FMS) for reduction of noise, and cavity enhancement, for prolongation of the interaction length between the light and the sample. Due to its unique properties, it has demonstrated unparalleled detection sensitivity when it comes to detection of molecular constituents in the gas phase. However, despite these, it has so far not been used for detection of atoms, i.e. for elemental analysis. The present work presents an assessment of the expected performance of Doppler-broadened (Db) NICE-OHMS for analytical atomic spectrometry, then referred to as noise-immune cavity-enhanced analytical atomic spectrometry (NICE-AAS). After a description of the basic principles of Db-NICE-OHMS, the modulation and detection conditions for optimum performance are identified. Based on a previous demonstrated detection sensitivity of Db-NICE-OHMS of 5 × 10- 12 cm- 1 Hz- 1/2 (corresponding to a single-pass absorbance of 7 × 10- 11 over 10 s), the expected limits of detection (LODs) of Hg and Na by NICE-AAS are estimated. Hg is assumed to be detected in gas phase directly while Na is considered to be atomized in a graphite furnace (GF) prior to detection. It is shown that in the absence of spectral interferences, contaminated sample compartments, and optical saturation, it should be feasible to detect Hg down to 10 zg/cm3 (10 fg/m3 or 10- 5 ng/m3), which corresponds to 25 atoms/cm3, and Na down to 0.5 zg (zg = zeptogram = 10- 21 g), representing 50 zg/mL (parts-per-sextillion, pps, 1:1021) in liquid solution (assuming a sample of 10 μL) or solely 15 atoms injected into the GF, respectively. These LODs are several orders of magnitude lower (better) than any previous laser-based absorption technique previously demonstrated under atmospheric

  2. Apprenticeship Learning Techniques for Knowledge Based Systems

    DTIC Science & Technology

    1988-12-01

    domain, such as medicine. The Odysseus explanation-based learning program constructs explanations of problem-solving actions in the domain of medical...theories and empirical methods so as to allow construction of an explanation. The Odysseus learning program provides the first demonstration of using the... Odysseus explanation-based learning program is presfuted, which constructs explanations of human problem-solving actions in the domain of medical di

  3. A Generalized Pivotal Quantity Approach to Analytical Method Validation Based on Total Error.

    PubMed

    Yang, Harry; Zhang, Jianchun

    2015-01-01

    The primary purpose of method validation is to demonstrate that the method is fit for its intended use. Traditionally, an analytical method is deemed valid if its performance characteristics such as accuracy and precision are shown to meet prespecified acceptance criteria. However, these acceptance criteria are not directly related to the method's intended purpose, which is usually a gurantee that a high percentage of the test results of future samples will be close to their true values. Alternate "fit for purpose" acceptance criteria based on the concept of total error have been increasingly used. Such criteria allow for assessing method validity, taking into account the relationship between accuracy and precision. Although several statistical test methods have been proposed in literature to test the "fit for purpose" hypothesis, the majority of the methods are not designed to protect the risk of accepting unsuitable methods, thus having the potential to cause uncontrolled consumer's risk. In this paper, we propose a test method based on generalized pivotal quantity inference. Through simulation studies, the performance of the method is compared to five existing approaches. The results show that both the new method and the method based on β-content tolerance interval with a confidence level of 90%, hereafter referred to as the β-content (0.9) method, control Type I error and thus consumer's risk, while the other existing methods do not. It is further demonstrated that the generalized pivotal quantity method is less conservative than the β-content (0.9) method when the analytical methods are biased, whereas it is more conservative when the analytical methods are unbiased. Therefore, selection of either the generalized pivotal quantity or β-content (0.9) method for an analytical method validation depends on the accuracy of the analytical method. It is also shown that the generalized pivotal quantity method has better asymptotic properties than all of the current

  4. Trends and Techniques for Space Base Electronics

    NASA Technical Reports Server (NTRS)

    Trotter, J. D.; Wade, T. E.; Gassaway, J. D.

    1979-01-01

    Simulations of various phosphorus and boron diffusions in SOS were completed and a sputtering system, furnaces, and photolithography related equipment were set up. Double layer metal experiments initially utilized wet chemistry techniques. By incorporating ultrasonic etching of the vias, premetal cleaning a modified buffered HF, phosphorus doped vapox, and extended sintering, yields of 98% were obtained using the standard test pattern. A two dimensional modeling program was written for simulating short channel MOSFETs with nonuniform substrate doping. A key simplifying assumption used is that the majority carriers can be represented by a sheet charge at the silicon dioxide silicon interface. Although the program is incomplete, the two dimensional Poisson equation for the potential distribution was achieved. The status of other Z-D MOSFET simulation programs is summarized.

  5. A simple analytical platform based on thin-layer chromatography coupled with paper-based analytical device for determination of total capsaicinoids in chilli samples.

    PubMed

    Dawan, Phanphruk; Satarpai, Thiphol; Tuchinda, Patoomratana; Shiowatana, Juwadee; Siripinyanond, Atitaya

    2017-01-01

    A new analytical platform based on the use of thin-layer chromatography (TLC) coupled with paper-based analytical device (PAD) was developed for the determination of total capsaicinoids in chilli samples. This newly developed TLC-PAD is simple and low-cost without any requirement of special instrument or skillful person. The analysis consisted of two steps, i.e., extraction of capsaicinoids from chilli samples by using ethanol as solvent and separation of capsaicinoids by thin-layer chromatography (TLC) and elution of capsaicinoids from the TLC plate with in situ colorimetric detection of capsaicinoids on the PAD. For colorimetric detection, Folin-Ciocalteu reagent was used to detect phenolic functional group of capsaicinoids yielding the blue color. The blue color on the PAD was imaged by a scanner followed by evaluation of its grayscale intensity value by ImageJ program. This newly developed TLC-PAD method provided a linear range from 50 to 1000mgL(-1) capsaicinoids with the limit of detection as low as 50mgL(-1) capsaicinoids. The proposed method was applied to determine capsaicinoids in dried chilli and seasoning powder samples and the results were in good agreement with those obtained by HPLC method.

  6. Studies of ferroelectric heterostructure thin films, interfaces, and device-related processes via in situ analytical techniques.

    SciTech Connect

    Aggarwal, S.; Auciello, O.; Dhote, A. M.; Gao, Y.; Gruen, D. M.; Im, J.; Irene, E. A.; Krauss, A. R.; Muller, A. H.; Ramesh, R.

    1999-06-29

    The science and technology of ferroelectric thin films has experienced an explosive development during the last ten years. Low-density non-volatile ferroelectric random access memories (NVFRAMS) are now incorporated in commercial products such as ''smart cards'', while high permittivity capacitors are incorporated in cellular phones. However, substantial work is still needed to develop materials integration strategies for high-density memories. We have demonstrated that the implementation of complementary in situ characterization techniques is critical to understand film growth and device processes relevant to device development. We are using uniquely integrated time of flight ion scattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry (SE) techniques to perform in situ, real-time studies of film growth processes in the high background gas pressure required to growth ferroelectric thin films. TOF-ISARS provides information on surface processes, while SE permits the investigation of buried interfaces as they are being formed. Recent studies on SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub x}Sr{sub 1{minus}x}TiO{sub 3} (BST) film growth and interface processes are discussed. Direct imaging of ferroelectric domains under applied electric fields can provide valuable information to understand domain dynamics in ferroelectric films. We discuss results of piezoresponse scanning force microscopy (SFM) imaging for nanoscale studies of polarization reversal and retention loss in Pb(Zr{sub x}Ti{sub 1{minus}x})O{sub 3} (PZT)-based capacitors. Another powerful technique suitable for in situ, real-time characterization of film growth processes and ferroelectric film-based device operation is based on synchrotrons X-ray scattering, which is currently being implemented at Argonne National Laboratory.

  7. Analytical Approach to Ballistic Dispersion of Projectile Weapons Based on Variant Launch Velocity

    DTIC Science & Technology

    2013-04-01

    projectiles , the coefficient of variation of vz0 is as small as 0.5% through rigorous studies of 225 distinct barrel shapes and varying in-bore pressure due to...Analytical Approach to Ballistic Dispersion of Projectile Weapons Based on Variant Launch Velocity by Michael M. Chen ARL-RP-437 April... Projectile Weapons Based on Variant Launch Velocity Michael M. Chen Weapons and Materials Research Directorate, ARL A reprint from

  8. Understanding wax screen-printing: a novel patterning process for microfluidic cloth-based analytical devices.

    PubMed

    Liu, Min; Zhang, Chunsun; Liu, Feifei

    2015-09-03

    In this work, we first introduce the fabrication of microfluidic cloth-based analytical devices (μCADs) using a wax screen-printing approach that is suitable for simple, inexpensive, rapid, low-energy-consumption and high-throughput preparation of cloth-based analytical devices. We have carried out a detailed study on the wax screen-printing of μCADs and have obtained some interesting results. Firstly, an analytical model is established for the spreading of molten wax in cloth. Secondly, a new wax screen-printing process has been proposed for fabricating μCADs, where the melting of wax into the cloth is much faster (∼5 s) and the heating temperature is much lower (75 °C). Thirdly, the experimental results show that the patterning effects of the proposed wax screen-printing method depend to a certain extent on types of screens, wax melting temperatures and melting time. Under optimized conditions, the minimum printing width of hydrophobic wax barrier and hydrophilic channel is 100 μm and 1.9 mm, respectively. Importantly, the developed analytical model is also well validated by these experiments. Fourthly, the μCADs fabricated by the presented wax screen-printing method are used to perform a proof-of-concept assay of glucose or protein in artificial urine with rapid high-throughput detection taking place on a 48-chamber cloth-based device and being performed by a visual readout. Overall, the developed cloth-based wax screen-printing and arrayed μCADs should provide a new research direction in the development of advanced sensor arrays for detection of a series of analytes relevant to many diverse applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. An Multivariate Distance-Based Analytic Framework for Connectome-Wide Association Studies

    PubMed Central

    Shehzad, Zarrar; Kelly, Clare; Reiss, Philip T.; Craddock, R. Cameron; Emerson, John W.; McMahon, Katie; Copland, David A.; Castellanos, F. Xavier; Milham, Michael P.

    2014-01-01

    The identification of phenotypic associations in high-dimensional brain connectivity data represents the next frontier in the neuroimaging connectomics era. Exploration of brain-phenotype relationships remains limited by statistical approaches that are computationally intensive, depend on a priori hypotheses, or require stringent correction for multiple comparisons. Here, we propose a computationally efficient, data-driven technique for connectome-wide association studies (CWAS) that provides a comprehensive voxel-wise survey of brain-behavior relationships across the connectome; the approach identifies voxels whose whole-brain connectivity patterns vary significantly with a phenotypic variable. Using resting state fMRI data, we demonstrate the utility of our analytic framework by identifying significant connectivity-phenotype relationships for full-scale IQ and assessing their overlap with existent neuroimaging findings, as synthesized by openly available automated meta-analysis (www.neurosynth.org). The results appeared to be robust to the removal of nuisance covariates (i.e., mean connectivity, global signal, and motion) and varying brain resolution (i.e., voxelwise results are highly similar to results using 800 parcellations). We show that CWAS findings can be used to guide subsequent seed-based correlation analyses. Finally, we demonstrate the applicability of the approach by examining CWAS for three additional datasets, each encompassing a distinct phenotypic variable: neurotypical development, Attention-Deficit/Hyperactivity Disorder diagnostic status, and L-dopa pharmacological manipulation. For each phenotype, our approach to CWAS identified distinct connectome-wide association profiles, not previously attainable in a single study utilizing traditional univariate approaches. As a computationally efficient, extensible, and scalable method, our CWAS framework can accelerate the discovery of brain-behavior relationships in the connectome. PMID:24583255

  10. School-based friendship networks and children's physical activity: A spatial analytical approach.

    PubMed

    Macdonald-Wallis, Kyle; Jago, Russell; Page, Angie S; Brockman, Rowan; Thompson, Janice L

    2011-07-01

    Despite the known health benefits, the majority of children do not meet physical activity guidelines, with past interventions to increase physical activity yielding little success. Social and friendship networks have been shown to influence obesity, smoking and academic achievement, and peer-led interventions have successfully reduced the uptake of adolescent smoking. However, the role of social networks on physical activity is not clear. This paper investigates the extent to which friendship networks influence children's physical activity, and attempts to quantify the association using spatial analytical techniques to account for the social influence. Physical activity data were collected for 986 children, aged 10-11 years old, from 40 schools in Bristol, UK. Data from 559 children were used for analysis. Mean accelerometer counts per minute (CPM) and mean minutes of moderate to vigorous physical activity per day (MVPA) were calculated as objective measures of physical activity. Children nominated up to 4 school-friends, and school-based friendship networks were constructed from these nominations. Networks were tested to assess whether physical activity showed spatial dependence (in terms of social proximity in social space) using Moran's I statistic. Spatial autoregressive modelling was then used to assess the extent of spatial dependence, whilst controlling for other known predictors of physical activity. This model was compared with linear regression models for improvement in goodness-of-fit. Results indicated spatial autocorrelation of both mean MVPA (I = .346) and mean CPM (I = .284) in the data, indicating that children clustered in friendship groups with similar activity levels. Spatial autoregressive modelling of mean MVPA concurred that spatial dependence was present (ρ = .26, p < .001), and improved model fit by 31% on the linear regression model. These results demonstrate an association between physical activity levels of children and their

  11. Studying pigments on painted plaster in Minoan, Roman and early Byzantine Crete. A multi-analytical technique approach.

    PubMed

    Westlake, Polly; Siozos, Panayiotis; Philippidis, Aggelos; Apostolaki, Chryssa; Derham, Brendan; Terlixi, Agni; Perdikatsis, Vasilios; Jones, Richard; Anglos, Demetrios

    2012-02-01

    Wall paintings spanning two millennia of Cretan painting history and technology were analysed in an effort to determine similarities and evolutions of painting materials and technology. A multi-technique approach was employed that combined the use of (a) laser-induced breakdown spectroscopy (LIBS) and Raman microspectroscopy, based on mobile instrumentation, appropriate for rapid, routine-level object characterization, and (b) non-destructive X-ray diffractometry (XRD), performed directly on the wall painting fragment, which provides detailed information on the minerals constituting the paint. Elemental analysis data obtained through LIBS were compared with molecular and crystal structure information from Raman spectroscopy and XRD. Cross-sections from selected samples were also investigated by means of optical microscopy and scanning electron microscopy coupled to micro-probe analysis and X-ray mapping that enabled identification of several mineral components of the paint confirming the results of the XRD analysis. In parallel, replica wall paintings, created with known pigments and binding media for reference purposes, were examined with optical microscopy and stain tested for organic materials. The overall study shows that the LIBS and Raman techniques offer key advantages, such as instrument mobility and speed of data collection and interpretation that are particularly important when dealing with on-site investigations. Thus, they are capable of providing important compositional information in an effective manner that enables quick surveying of wall paintings and permit targeted sample selection for further analysis by advanced laboratory techniques.

  12. Information fusion based techniques for HEVC

    NASA Astrophysics Data System (ADS)

    Fernández, D. G.; Del Barrio, A. A.; Botella, Guillermo; Meyer-Baese, Uwe; Meyer-Baese, Anke; Grecos, Christos

    2017-05-01

    Aiming at the conflict circumstances of multi-parameter H.265/HEVC encoder system, the present paper introduces the analysis of many optimizations' set in order to improve the trade-off between quality, performance and power consumption for different reliable and accurate applications. This method is based on the Pareto optimization and has been tested with different resolutions on real-time encoders.

  13. A Visual Analytics Based Decision Support Methodology For Evaluating Low Energy Building Design Alternatives

    NASA Astrophysics Data System (ADS)

    Dutta, Ranojoy

    The ability to design high performance buildings has acquired great importance in recent years due to numerous federal, societal and environmental initiatives. However, this endeavor is much more demanding in terms of designer expertise and time. It requires a whole new level of synergy between automated performance prediction with the human capabilities to perceive, evaluate and ultimately select a suitable solution. While performance prediction can be highly automated through the use of computers, performance evaluation cannot, unless it is with respect to a single criterion. The need to address multi-criteria requirements makes it more valuable for a designer to know the "latitude" or "degrees of freedom" he has in changing certain design variables while achieving preset criteria such as energy performance, life cycle cost, environmental impacts etc. This requirement can be met by a decision support framework based on near-optimal "satisficing" as opposed to purely optimal decision making techniques. Currently, such a comprehensive design framework is lacking, which is the basis for undertaking this research. The primary objective of this research is to facilitate a complementary relationship between designers and computers for Multi-Criterion Decision Making (MCDM) during high performance building design. It is based on the application of Monte Carlo approaches to create a database of solutions using deterministic whole building energy simulations, along with data mining methods to rank variable importance and reduce the multi-dimensionality of the problem. A novel interactive visualization approach is then proposed which uses regression based models to create dynamic interplays of how varying these important variables affect the multiple criteria, while providing a visual range or band of variation of the different design parameters. The MCDM process has been incorporated into an alternative methodology for high performance building design referred to as

  14. Accelerator based techniques for contraband detection

    NASA Astrophysics Data System (ADS)

    Vourvopoulos, George

    1994-05-01

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

  15. Chemical speciation of arsenic-accumulating mineral in a sedimentary iron deposit by synchrotron radiation multiple X-ray analytical techniques.

    PubMed

    Endo, Satoshi; Terada, Yasuko; Kato, Yasuhiro; Nakai, Izumi

    2008-10-01

    The comprehensive characterization of As(V)-bearing iron minerals from the Gunma iron deposit, which were probably formed by biomineralization, was carried out by utilizing multiple synchrotron radiation (SR)-based analytical techniques at BL37XU at SPring-8. SR microbeam X-ray fluorescence (SR-mu-XRF) imaging showed a high level of arsenic accumulation in the iron ore as dots of ca. 20 microm. Based on SEM observations and SR X-ray powder diffraction (SR-XRD) analysis, it was found that arsenic is selectively accumulated in strengite (FePO4 x 2H2O) with a concentric morphology, which may be produced by a biologically induced process. Furthermore, the X-ray absorption fine structure (XAFS) analysis showed that arsenic in strengite exists in the arsenate (AsO4(3-)) form and is coordinated by four oxygen atoms at 1.68 angstroms. The results suggest that strengite accumulates arsenic by isomorphous substitution of AsO4(3-) for PO4(3-) to form a partial solid-solution of strengite and scorodite (FeAsO4 x 2H2O). The specific correlation between the distribution of As and biominerals indicates that microorganisms seems to play an important role in the mineralization of strengite in combination with an arsenic-accumulating process.

  16. Entry guidance with real-time planning of reference based on analytical solutions

    NASA Astrophysics Data System (ADS)

    Yu, Wenbin; Chen, Wanchun

    2015-05-01

    In this paper, first, we develop new analytical solutions to hypersonic gliding problem. In the derivation of these solutions, we propose an innovative method based on spectral decomposition for solving a special type of linear system with variable coefficients, where the system matrix can be expressed as the product of a scale function and a constant matrix. Next, we design an entry guidance based on these analytical solutions. In the guidance, the downrange analytical expression is used to plan the longitudinal reference profile satisfying the downrange requirement in real time. Two bank reversals are needed to eliminate the crossrange error. The first is planned by the crossrange analytical expression such that the second is at a specified point near the end of the flight. After the first bank reversal is performed, the second is slightly corrected using the trajectory simulation. Because the longitudinal reference profile and bank reversals are planned onboard, the entry guidance can handle various urgent tasks and deal well with large dispersions in the initial conditions, aerodynamic model and atmospheric model.

  17. OLED-based sensor array for simultaneous monitoring of multiple analytes

    NASA Astrophysics Data System (ADS)

    Cai, Yuankun; Shinar, Ruth; Zhou, Zhaoqun; Shinar, Joseph

    2007-09-01

    A compact, photoluminescence (PL)-based sensor array, utilizing tris(quinolinolate) Al OLED pixels as the excitation sources, for sequential or simultaneous monitoring of dissolved oxygen (DO), glucose, lactate, and alcohol, is described. The DO is monitored through its effect on the PL lifetime of the oxygen-sensitive dye Pt octaethylporphyrin (PtOEP) embedded in a polystyrene film. The other analytes are monitored through their oxidation, catalyzed by an appropriate oxidase, which reduces the amount of DO in their vicinity. The OLED pixels are fabricated on a glass substrate; each pixel is typically 2×2 mm2, with a 2 mm gap between the pixels. Two OLED pixels are associated with the detection of each of the analytes. The pixels are individually addressable, enabling consecutive detection of the different analytes within a few minutes utilizing a single photodetector (PD). Simultaneous detection is achieved by using an array of PDs. The OLED-based sensing array is compact and uniquely simple in its ease of fabrication and integration. Its performance attributes are comparable to those obtained for a single analyte using any excitation source. The potential of small-size, multi-color OLED pixel arrays for multianalyte detection is also discussed.

  18. Scattering by a zero-thickness PEC disk: A new analytically regularizing procedure based on Helmholtz decomposition and Galerkin method

    NASA Astrophysics Data System (ADS)

    Lucido, Mario; Panariello, Gaetano; Schettino, Fulvio

    2017-01-01

    The aim of this paper is the introduction of a new analytically regularizing procedure, based on Helmholtz decomposition and Galerkin method, successfully employed to analyze the electromagnetic scattering by zero-thickness perfectly electrically conducting circular disk. After expanding the fields in cylindrical harmonics, the problem is formulated as an electric field integral equation in the vector Hankel transform domain. Assuming as unknowns the surface curl-free and divergence-free contributions of the surface current density, a second-kind Fredholm infinite matrix-operator equation is obtained by means of Galerkin method with expansion functions reconstructing the expected physical behavior of the surface current density and with closed-form spectral domain counterparts, which form a complete set of orthogonal eigenfunctions of the most singular part of the integral operator. The coefficients of the scattering matrix are single improper integrals which can be quickly computed by means of analytical asymptotic acceleration technique. Comparisons with the literature have been provided in order to show the accuracy and efficiency of the presented technique.

  19. Does leaf chemistry differentially affect breakdown in tropical versus temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Treesearch

    Marcelo Ardon; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to...

  20. ICL-Based OF-CEAS: A Sensitive Tool for Analytical Chemistry.

    PubMed

    Manfred, Katherine M; Hunter, Katharine M; Ciaffoni, Luca; Ritchie, Grant A D

    2017-01-03

    Optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) using mid-infrared interband cascade lasers (ICLs) is a sensitive technique for trace gas sensing. The setup of a V-shaped optical cavity operating with a 3.29 μm cw ICL is detailed, and a quantitative characterization of the injection efficiency, locking stability, mode matching, and detection sensitivity is presented. The experimental data are supported by a model to show how optical feedback affects the laser frequency as it is scanned across several longitudinal modes of the optical cavity. The model predicts that feedback enhancement effects under strongly absorbing conditions can cause underestimations in the measured absorption, and these predictions are verified experimentally. The technique is then used in application to the detection of nitrous oxide as an exemplar of the utility of this technique for analytical gas phase spectroscopy. The analytical performance of the spectrometer, expressed as noise equivalent absorption coefficient, was estimated as 4.9 × 10(-9) cm (-1) Hz(-1/2), which compares well with recently reported values.